From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “Astronomers observe potential magnetic flip around a supermassive black hole”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

05/05/2022 [Just now in social media.]

Contacts at the IAC:
José Acosta,
jose.acosta@iac.es

Josefa Becerra,
josefa.becerra.gonzalez@iac.es

Artist’s impression of the unusual eruption of the galaxy 1ES 1927+654. A sudden reversal of the magnetic field around its million-solar-mass black hole may have triggered the outburst. Credit: NASA.

An international research, in which a team from the Instituto de Astrofísica de Canarias (IAC) has participated, has provided new evidence for an enigmatic outburst from a galaxy 216 million light-years away, proposing a new interpretation based on a spontaneous flip of the magnetic field surrounding its central black hole. The study has used joint data from different satellites and telescopes, including the Telescopio Nazionale Galileo (TNG) [below] and the Gran Telescopio Canarias (GTC)[below], both located at the Roque de los Muchachos Observatory (Garafía, La Palma). The results will be published in the coming days in The Astrophysical Journal.

In early March 2018, the All-Sky Automated Survey for Supernovae alerted astronomers that a galaxy called 1ES 1927+654 had brightened by nearly 100 times in visible light. A search for earlier detection by the NASA-funded Asteroid Terrestrial-impact Last Alert System showed that the eruption had begun months earlier, at the end of 2017. Three months after the discovery the X-ray emission from the galaxy disappeared.

“Rapid changes in visible and ultraviolet light have been seen in a few dozen galaxies similar to this one,” says Sibasish Laha, a research scientist at the University of Maryland and NASA’s Goddard Space Flight Center in the United States. “But this event marks the first time we’ve seen X-rays dropping out completely while the other wavelengths brighten.”

“An earlier interpretation of the eruption suggested that it was triggered by a star that passed so close to the black hole it was torn apart, disrupting the flow of gas,” says Josefa Becerra, researcher at the IAC and co-author of the article. “However, such an event would fade out more rapidly than this outburst.”

The research team analyzed new and archival observations across the spectrum. NASA’s Neil Gehrels Swift Observatory and ESA’s (European Space Agency) XMM-Newton satellite provided UV and X-ray measurements.

National Aeronautics and Space Administration Neil Gehrels Swift X-ray, and UV/Visible light Observatory.

The European Space Agency [La Agencia Espacial Europea] [Agencia Espacial Europea][Agence spatiale européenne][Europäische Weltraumorganisation](EU) XMM Newton X-ray Telescope.

Visible light observations came from the Telescopio Nazionale Galileo (TNG) and the Gran Telescopio Canarias (GTC or Grantecan), both located at the Roque de los Muchachos Observatory on the island of La Palma. Radio measurements were acquired from the Very Long Baseline Array, a network of 10 radio telescopes located across the United States; the Very Large Array in New Mexico; and the European VLBI Network.

NRAO Very Long Baseline Array(US)-Very Long Baseline Array-USA

National Radio Astronomy Observatory(US)Karl G Jansky Very Large Array located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes.

European Very Long Baseline Interferometry Network

“The high quality of the GTC/OSIRIS spectrum allows us to disentangle the stellar contribution from that of the active core,” says José Acosta, IAC researcher and co-author of the paper. “The stellar population of the host galaxy is dominated by young stars and the nuclear spectrum is dominated by strong emission lines,” he says.

Most big galaxies, including our own Milky Way, host a supermassive black hole weighing millions to billions of times the Sun’s mass. When matter falls toward one, it first collects into a vast, flattened structure called an accretion disk. As the material slowly swirls inward, it heats up and emits visible, UV, and lower-energy X-ray light. Near the black hole, a cloud of extremely hot particles – called the corona – produces higher-energy X-rays. The brightness of these emissions depends on how much material streams toward the black hole.

The unique disappearance of the X-ray emission provides astronomers with an important clue. They suspect the black hole’s magnetic field creates and sustains the corona, so any magnetic change could impact its X-ray properties. “A magnetic reversal, where the north pole becomes south and vice versa, seems to best fit the observations,” says co-author Mitchell Begelman, a professor in the department of astrophysical and planetary sciences at the University of Colorado-Boulder who developed the model. “The field initially weakens at the outskirts of the accretion disk, leading to greater heating and brightening in visible and UV light,” he explains.

As the flip progresses, the field becomes so weak that it can no longer support the corona and the X-ray emission vanishes. The magnetic field then gradually strengthens in its new orientation. In Oct 2018, about 3-4 months after they disappeared, the X-rays came back, indicating that the corona had been fully restored.

Magnetic reversals are likely to be common events in the cosmos. The geologic record shows that Earth’s field flips unpredictably, averaging a few reversals every million years in the recent past. The Sun, by contrast, undergoes a magnetic reversal as part of its normal cycle of activity, switching north and south poles roughly every 11 years.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES) via Manu Garcia-a friend from IAC : “An atlas of active galaxies shows that superwinds are common even in the most dormant”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

via

Manu Garcia, a friend from IAC-Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias](ES).

The universe around us.
Astronomy, everything you wanted to know about our local universe and never dared to ask.

4.27.22
Silbia López de Lacalle
sll@iaa.es

Color image of NGC4321 at a large scale, combining three images with different wide filters. Source: IAA-CSIC, Nordic Optical Telescope.

Nordic Optical Telescope [funded by Denmark, Sweden, Norway, Finland, and (since 1997) Iceland], at IAC Institute of Astrophysics of the Canary Islands[Instituto de Astrofísica de Canarias](ES) The Roque de los Muchachos Observatory on La Palma in The Canary Islands[Instituto de Astrofísica de Canarias ](ES) Altitude 2,396 m (7,861 ft).

The Institute of Astrophysics of Andalusia (IAA-CSIC) is studying in depth a sample of LINERs, the least luminous type of active galaxy, and finds that galactic superwinds occur in half of them

Galactic superwinds, capable of generating large amounts of energy and transporting gas over great distances, play a fundamental role in the evolution of galaxies. In the case of active galaxies, whose brightness is attributed to the existence of a supermassive black hole surrounded by a disk of matter that feeds it, it is common to observe superwinds produced by the black hole. However, the properties of these phenomena have yet to be characterized in detail, and in the less bright active galaxies they are hardly known. A study carried out by researchers at the Institute of Astrophysics of Andalusia (IAA-CSIC) has published the most complete atlas of superwinds in a type of low-power active galaxies that are the most abundant in the local universe.

“It is believed that all galaxies with an active nucleus in their center generate the presence of so-called galactic winds, which are nothing more than dust and gas from the host galaxy that are expelled out at high speeds,” says Laura Hermosa, a researcher at the IAA-CSIC that leads the work–. Until now, it had not been verified whether the existence of these winds was also common in the less active nuclei that exist, the so-called LINERs”.

LINERs, an acronym for “low ionization nuclear emission line region”, represent about a third of the galaxies in our environment. Its nucleus emits a specific type of radiation (the emission of weakly ionized or neutral atoms), and its energy shows an intensity greater than galaxies whose energy only comes from stars, but less than those in which supermassive black holes are consuming material very actively.

In the latter, galactic superwinds generate feedback processes that can even stop star formation, but until now it was not even known how frequent they are in LINER galaxies. This could be due to the fact that the particularities of these objects prevent their formation or to an observation bias: these phenomena tend to be found in very powerful active nuclei, where they are easily identified, since the fluxes usually show a scale proportional to the luminosity of the nucleus. active.

Combination of the central regions of three galaxies in the sample (NGC5813, NGC5363 and NGC0266), showing continuous red and extended emission from ionized gas in blue-green. All are superwind candidates, although in the third the emission in the spiral arms by star-forming regions stands out. Source: IAA-CSIC, NOT telescope.

“In this work we have obtained images of the ionized gas of a sample of seventy LINER galaxies, becoming the largest sample in this type of study carried out to date. The winds are visible in the images as an extended emission emerging from the galactic core. Combining the information from the images with existing spectroscopic information in the literature, we have quantified for the first time how common winds are in these types of active galaxies and found that approximately 50% of all LINERs in the local universe show galactic superwinds.” , points out Laura Hermosa (IAA-CSIC).

The work has also made it possible to divide the sample into four different types of wind configurations depending on how the emission is distributed: “nucleus-halo” for unresolved nuclear emission, “disk” for structures similar to small spiral arms or disks, ” bubble” for the biconical, filamentary, or bubble-shaped structures emerging from the nucleus that the team identifies as superwind candidates, and “dusty” when large amounts of dust obscure the nuclear emission.

“Furthermore, combining the optical information with the X-rays, we see a correlation between both emissions for 60% of the sample, which indicates that both emissions are generated in the same spatial region of the active galaxies (LINER type), as shown. has already seen in others of greater luminosity”, concludes Laura Hermosa (IAA-CSIC).

Science paper:
Astronomy & Astrophysics

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “Astronomers discover a four-planet system with a peculiar migration process”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

5.2.22
Contact at the IAC:

Hans J. Deeg
hdeeg@iac.es

Felipe Murgas
fmurgas@iac.es

Enric Pallé
epalle@iac.es

Artist’s impression of a planetary system composed of rocky, low-mass planets orbiting their star. Credit: Gabriel Pérez Díaz (IAC).

An international research, in which the Instituto de Astrofísica de Canarias (IAC) participates, has discovered a new planetary system comprised of 4 planets orbiting the star TOI-500. This is the first system known to host an Earth analogue with a period shorter than one day and 3 additional low-mass planets whose orbital configuration can be explained via a non-violent and smooth migration scenario. The study is published in the journal Nature Astronomy.

The inner planet, dubbed TOI-500b, is a so-called ultra-short period (USP) planet, as its orbital period is only 13 hours. It is regarded as an Earth analogue, that is, an Earth-like rocky planet with radius, mass, and density comparable to those of our planet. “In contrast to Earth, though, its proximity to the star makes it so hot (about 1350 °C) that its surface is most likely an immense expanse of lava,” says Luisa Maria Serrano, researcher at the of the Physics Department of The University of Turin [Università degli Studi di Torino](IT) and first author of the paper. The new planet could be a true reflection of what the Earth will look like in the future, when the Sun becomes a red giant star, much bigger and brighter than it is now.

TOI-500b was initially identified as a planet candidate by NASA’s Transiting Exoplanet Survey Satellite (TESS), a space telescope designed to look for planets in orbit around nearby bright stars using the transit method.

Planet transit. NASA/Ames.

The National Aeronautics and Space Agency Massachusetts Institute of Technology TESS – Transiting Exoplanet Survey Satellite replaced the Kepler Space Telescope in search for exoplanets. TESS is a NASA Astrophysics Explorer mission led and operated by The Massachusetts Institute of Technology , and managed by NASA’s Goddard Space Flight Center.

This method measures the minute decrease of the brightness of a star as the planet crosses the stellar disk as seen from the telescope. TOI-500b was subsequently confirmed thanks to a one-year-long observing campaign carried out by the University of Turin with the HARPS spectrograph at The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europaiche Sûdsternwarte] (EU)(CL).

ESO/HARPS spectrograph at Cerro La Silla.

3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

The analysis of the TESS and HARPS data has provided precise measurements of the mass; radius and orbital parameters of the inner ultra-short period planet TOI-500b. “The HARPS measurements have also allowed us to detect 3 additional low-mass planets orbiting TOI-500 every 6.6, 26.2, and 61.3 days. TOI-500 is a remarkable planetary system, important for understanding the dynamical fate of planets,” says Davide Gandolfi, researcher at the of the Physics Department of the University of Turin and co-author of the paper.

The novelty presented by the newly published paper lies in the migration process that led the planetary system to its current configuration. “It is commonly accepted that ultra-short period planets did not form in their current-day orbits, as the innermost regions of their natal protoplanetary disk have inadequate density and temperature to form planets. They must have originated further out and then migrated inwards close to their host star,” says Hans J. Deeg, researcher at the IAC who participated in the study.

Although there is no consensus on the migration process, it is often believed to occur via a violent process, involving planet-planet scattering, which would shrink and excite the orbits of the planets. In their study the authors show that the planets orbiting TOI-500 may have always been on nearly circular orbits, and then migrated inwards following a so-called secular and quasi-static migration process that lasted about 2 billion years. “This is a quiet migration pattern, in which planets move slowly on orbits closer and closer to their star, without bumping into each other and without exiting their orbits,” explains Felipe Murgas, researcher at the IAC and co-author of the paper.

“This paper demonstrates the importance of coupling the discovery of systems hosting USP planets with numerical simulations to test possible migratory processes that may have led them to their current orbital configuration,” says Enric Pallé, researcher at the IAC and co-author of the article. “Acquiring data across a long time baseline makes it possible to unveil the inner architecture of systems similar to TOI-500 and understand how planets have settled into their orbits”, conclude.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “IAC scientists obtain one of the most general validations of Einstein’s Principle of Equivalence”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

4.11.22
Carlos M. Gutiérrez
cgc@iac.es

Nataliya Ramos Chernenko
nataliya.ramos.chernenko@iac.es

The figure shows a cluster of stars like the ones analysed in this work. The emitted light loses energy as it escapes the gravitational field of each star. This energy loss manifests itself as a reddening that is larger for main-sequence stars with relatively small radii (right) than for giant-phase stars with larger radii (left). Credit: Gabriel Pérez Díaz (IAC). Background image: ESA/Hubble and NASA. Magnifiers based in an illustration by freepic.es.

The study shows the potential of major astronomical observatories to test the laws of physics and to show their universal character. The results are published in The Astrophysical Journal.

The General Theory of Relativity is one of the basic pillars of modern physics. One of the bases which support Einstein`s theory is the Principle of Equivalence. Using this principle one can infer that light which escapes from a region with a strong gravitational field loses energy as it travels, so that its wavelength shifts to the red. This phenomenon is known as the gravitational redshift, and measuring it gives a fundamental test of gravitation.

Although astrophysics offers a wide variety of physical conditions where this reshift should be measurable, until quite recently observational evidence for this was limited to the light emitted by the Sun, white dwarfs, and quasars. Now a new study led by researchers at the Instituto de Astrofísica de Canarias (IAC) and The University of La Laguna [Universidad de La Laguna](ES) have managed to measure the gravitational redshift for several thousand stars on the main sequence (where most stars spend 90% of their lifetimes) and in giant stars, all of them in around one hundred open star clusters.

The study stems from the idea of using astrophysical observations to test the validity of physical laws, extending the tests in space and time on cosmic scales and in situations outside the scope of laboratories, such as gravitational fields orders of magnitude stronger than those on Earth. “The aim of our work has been to measure the effect of the gravity of the stars on the light we receive, and to see whether the results of our measurements are in agreement with the predictions of theory, and in particular with the Principle of Equivalence” explains the IAC/ULL researcher Carlos M. Guitérrez, who is the first author of the article.

The researchers have studied stars which belong to open star clusters in the Milky Way, and which therefore share the same motions, and have measured the differences in the energies of the photons received, depending on the type of stars from which they were emitted. “This effect is bigger the greater the mass of the star, but small the greater its radius” points out Gutiérrez so that the photons emitted hy stars similar to the Sun lose two parts in a million of their energies, while stars in the giant phase, with much larger radii, show a much smaller comparative effect.

To carry out this study the authors have taken a large sample of stars from the catalogue of 7 million stars provided by ESA’s Gaia mission, selecting around 100 open clusters with 8,000 stars distributed around the whole of the Galaxy.

European Space Agency [La Agencia Espacial Europea][Agence spatiale européenne][Europäische Weltraumorganisation](EU) GAIA satellite.

For IAC and ULL researcher Nataliya Ramos Chernenko, co-author of the article, “This study entails an important advance, because there have been very few previous studies of “normal” stars, apart from the Sun. It is also one of the first studies based on stars which are not degenerate, that is to say which are not in their final phases of existance, and which includes dwarfs and giants in open clusters”.

As well as obtaining one of the most general confirmations of a basic physical concept, the study has also shown that estimates of the masses and radii of stars based on theoretical models are correct. “Testing the predictions of General Relativity allows us to rule out other theories of gravity which have been proposed as alternatives to explain the domination of dark matter and dark energy in the universe, as well as to verify systems for positioning and navigation such as GPS; which would not work if Einstein’s theory were not taken into account” concludes Gutiérrez.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES) via Manu Garcia-a friend from IAC: “Caught in the act- the winds driven by supermassive black holes directly impact star formation”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

3.21.22 [Just now in email from From Manu Garcia, a friend from IAC-Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias](ES).

Patricia Bessiere
pbessiere@iac.es

Cristina Ramos Almeida
cra@iac.es

Winds launched by a supermassive black hole impact the formation of new stars in the galaxy Markarian 34. The fraction of light coming from a young stellar population (YSP) increases at the edges of the approaching side of the wind (blue contours) compared to the rest of the galaxy. The receding side of the wind, faster and more turbulent (red contours), might be preventing star formation. Credits: G. Pérez Díaz/NASA/ESA Hubble/Mikulki Archives for Space Telescopes Archive .

Patricia Bessiere, a researcher at the Instituto de Astrofísica de Canarias (IAC), has led research which has used data from the KECK telescope in Hawaii to understand the impact that active galactic nuclei have on star formation in their host galaxies.

W.M. Keck Observatory two ten meter telescopes operated by California Institute of Technology and The University of California, at Mauna Kea Observatory, Hawaii, altitude 4,207 m (13,802 ft). Credit: Caltech.

Keck Laser Guide Star Adaptive Optics on two 10 meter Keck Observatory telescopes, at Maunakea Observatory, Hawaii, altitude 4,207 m (13,802 ft).

The results are published today in the journal MNRAS Letters.

One of the key questions that astronomers are trying to answer is ‘Why do galaxies look the way they do?’. Computer simulations of how galaxies formed and evolved suggest that there should be many more very large galaxies than we actually observe, so what is the missing ingredient in these simulations? What is the process within galaxies that stops too many stars from forming?

We now know that all massive galaxies harbour a super massive black hole at their heart, which is millions or billions of times heavier than our own sun. When the amount of gas from within the galaxy falling onto the black hole abruptly increases, it becomes incredibly hot and vast amounts of energy are released into the galaxy. When a black hole is going through such a phase, it is known as an Active Galactic Nucleus or AGN and astronomers believe that this phenomenon may be the missing ingredient they have been searching for. Some of the energy released by the AGN will have the effect of pushing the gas out of the galaxy, a process known as ‘AGN driven winds’ or ‘AGN feedback’, which means that there will be less gas from which to form new stars.

A team of scientists at the IAC have been trying to catch this process in action. Using integral field spectroscopy (IFS) from the KCWI instrument on the Keck telescope in Hawaii, which allows astronomers to simultaneously take many spectra at different locations in the galaxy, they have been able to map both the AGN driven winds and the ages of stars across the inner region of the well studied active galaxy Markarian 34.

Keck Cosmic Web Imager on Keck 2.

Taking this approach, they hoped to understand if these winds were having a direct impact on star formation. The results of this study are published today in MNRAS Letters as part of the “QSOFEED” project (http://research.iac.es/galeria/cra/qsofeed/) whose aim is to understand how supermassive black holes affect the galaxies that host them.

What the team found shows that that AGN and the winds that they drive have a complex impact on their host galaxies. On one side of the galaxy, they have shown that ahead and at the edges of the wind, new stars are being formed. Patricia Bessiere, who led the study, explains why this may be happening. “Some theoretical studies and computer simulations suggest that, as the AGN driven wind passes through the galaxy, the denser, cooler gas ahead and to the sides is compressed, making the conditions for star formation more favourable. This means that the wind is actually triggering star formation rather than suppressing it.”

However, on the other side of the galaxy, the rate of star formation is found to be unaffected by the passage of the wind. The team suggest that this might be because the wind here is faster and more turbulent meaning Ground based Optical Astronomythat the conditions for star formation are not similarly enhanced. Cristina Ramos Almeida, an IAC researcher and co-author of the study, explains that “what we are seeing here may be evidence of ‘preventive’ feedback, meaning that the wind is disrupting the gas in the galaxy so that it can’t collapse to form new stars”.

“This study demonstrates that the relationship between AGN and their host galaxies is complex and can impact different regions in different ways. The findings of this observational investigation will be important in informing future modelling of galaxy evolution and the role played by AGN”, explains Patricia Bessiere.

To expand our understanding of this relationship, the team now plan to extend their study by observing a larger sample of AGN using the MEGARA instrument, installed on the 10 m Gran Telecopio CANARIAS (GTC).

MEGARA instrument, installed on the 10 m Gran Telecopio CANARIAS (GTC)

This will allow the team to obtain IFS data which they will use to characterise the spatial distribution of both the winds and the stellar populations. This will help astronomers to understand the details of the relationship between the AGN and star formation and, importantly, how common such interactions are.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “A cold wind during the discovery outburst of a black hole”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

3.15.22

Daniel Mata Sánchez
Teodoro Muñoz Darias
Virginia Anahi Cúneo
Montserrat Armas Padilla
JavierSánchez Sierras
María Guayente Panizo Espinar
Jorge Casares Velázquez
J. M. Corral-Santana
The European Southern Observatory [La Observatorio Europeo Austral][Observatoire européen austral][Europäische Südsternwarte](EU)(CL)

Normalized spectra of the GTC-1 (blue) and GTC-2 epochs (black) at Hα. Telluric bands and diffuse interstellar bands, as well as reference velocities (1000 and 1250 km/s) have been marked to highlight the blue-shifted absorption produced by the wind.

We present 12 epochs of optical spectroscopy taken across the discovery outburst of the black hole (BH) candidate MAXI J1803-298 with the Gran Telescopio Canarias [below] and the ESO Very Large Telescope.

The European Southern Observatory [La Observatorio Europeo Austral][Observatoire européen austral][Europäische Südsternwarte](EU)(CL), Very Large Telescope at Cerro Paranal in the Atacama Desert •ANTU (UT1; The Sun ) •KUEYEN (UT2; The Moon ) •MELIPAL (UT3; The Southern Cross ), and •YEPUN (UT4; Venus – as evening star). Elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

The source followed a standard outburst evolution. This means it passed through the so-called “hard” and “soft” states, defined in terms of the relative contribution of high to low energy X-rays. The system displays a “triangular” shape in the hardness intensity diagram, consistent with that seen in high-inclination BH transients and the previously reported detection of X-ray dips. The two epochs observed during the initial “hard” state exhibited asymmetric emission-line profiles, including a P-Cygni profile simultaneously detected in Hα and He I 6678 Å. This type of profile, described as a blue-shifted absorption and a red-shifted emission, has been previously seen in a number of objects (e.g., massive stars and supernovae), and provides conclusive proof for the presence of winds. The remaining spectra, obtained during the transition to the soft state and the subsequent decay, are instead characterized by narrower, double-peaked emission lines embedded into broad absorption components. One epoch (intermediate state) also includes near-infrared coverage, revealing complex line profiles in the hydrogen Paschen and Bracket series, which suggests that the outflow is still present during the outburst decay through the soft state. The growing list of low-mass X-ray binaries with optical and near-infrared outflow signatures indicates that these are common features. Furthermore, we use the correlation previously introduced by some of us to constrain the mass of the compact object. Using the lowest luminosity spectrum, together with previous constraints on the binary parameters, allows us to favour a compact object mass of ~3-10 solar masses, further supporting its BH nature.

Science paper:
The Astrophysical Journal

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “Astronomers develop new method for taking the temperature of black holes”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

3.15.22
Almudena Prieto
aprieto@iac.es

Artist’s illustration of a cold, heavy black hole at the centre of a galaxy, with 100 million times the mass of our Sun, heating its surroundings to thousands of degrees, compared to a smaller, superheated stellar black hole, with 10 times the mass of our Sun, but capable of heating its surroundings to millions of degrees. Credit: Gabriel Pérez Diaz, SMM-IAC.

An international research team led by researchers at the Instituto de Astrofísica de Canarias (IAC) has found a new method for measuring the masses of black holes based on the temperature of the gas which surrounds them when they are active. The results of the work have recently been published in the journal MNRAS.

The confirmation of the existence of black holes is one of the most basic results in astrophysics. There is a wide range of masses of black holes, from stellar-mass black holes, which are the result of the catastrophic final phase of very massive stars and have masses comparable to stars, to the supermassive black holes at the centres of most galaxies.

The mass of a black hole is for the moment the only parameter which scientists are able to measure. A recent article led by the researcher at the Instituto de Astrofísica de Canarias (IAC) Almudena Prieto, has shown an original method for measuring the mases of black holes, from those of stellar mass to the supermassive variety, based on a simple measurement of the emission spectrum of the ionized gas which is produced in the surroundings of a black hole when it is active, i.e. when it is “smallowing” the matter which falls into its gravitational field.

This new method is based on a theory first proposed in 1973, applied to binary stars which emit X-rays, each of which contain a compact object, usually a black hole, and a companion star. “This method opens a new possibility to measure black hole masses, for black holes of stellar mass, and also for intermediate mass and supermassive black holes” explains the researcher. “At the same time, thanks to its theoretical basis, the new method offers the possibility of determining the spin of a black hole as well as its mass.”

The smaller the hotter – the larger the cooler

The research has also given some results which surprised the researchers. “A curious result of this work, perhaps counterintuitive, is that the more massive the black hole, the more inactive it becomes and the cooler is the medium which surrounds it” explains Alberto Rodríguez Ardilla, a researcher at the Pico dos Dias Observatory [Observatório Pico dos Dias](BR), and co-author of the article. “The opposite occurs when they have less mass, in which case they are able to heat the material around them to millions of degrees, although only when they are active” adds Rodríguez Ardilla

Rodríguez Ardilla was an invited researcher at the IAC on the Severo Ochoa Programme in 2014, and carried out a large part of the research which is published in this recent article during a second stay of a year, funded by the Government of Brazil in 2018. This study is part of the project PARSEC which studies, at multiple wavelengths, the nuclei of local galaxies and the accretion processes onto their central black holes. The data for the project were obtained with the Gemini South Telescope and at the SOAR observatory in Chile, thanks to the participation of Brazil in these observatories.

The National Science Foundation NOIRLab National Optical Astronomy Observatory Gemini South telescope on the summit of Cerro Pachón at an altitude of 7200 feet. There are currently two telescopes commissioned on Cerro Pachón, Gemini South and the SOAR Telescope — Southern Astrophysics Research Telescope. A third, the Vera C. Rubin Observatory, is under construction.

NSF NOIRLab NOAO Southern Astrophysical Research [SOAR] telescope, situated on Cerro Pachón, just to the southeast of Cerro Tololo, on the NOIRLab NOAO AURA site at an altitude of 2,700 meters (8,775 feet) above sea level.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES) via Manu Garcia-a friend from IAC. : “They glimpse the structure of the supermassive black hole at the center of our galaxy”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

via

Manu Garcia, a friend from IAC.

The universe around us.
Astronomy, everything you wanted to know about our local universe and never dared to ask.

3.11.2022
Silbia López de Lacalle
sll@iaa.es

The IAA-CSIC leads a study that reveals the almost circular shape of Sagittarius A* (Sgr A*), the supermassive black hole located in the center of the Milky Way. The shape indicates that the axis of rotation of the flow of matter surrounding the black hole (or a possible jet) may be pointing toward Earth.

They glimpse the structure of the supermassive black hole at the center of our galaxy. Credit: IAA.

We know that most galaxies harbor a supermassive black hole at their center, and that these objects can influence both their immediate environment and the evolution of galaxies. And ours, the Milky Way, is no exception: in its central regions, 26,000 light years from Earth, is Sagittarius A* , a black hole with a mass of about four million suns. Sagittarius A* (Sgr A*) is the closest supermassive black hole to Earth, and is the ideal candidate to study what happens in the vicinity of these objects. A study published today [The Astrophysical Journal] reveals that its intrinsic structure is almost circular.

In 2020, the Nobel Prize in Physics was awarded for studies of Sgr A* , which have shown that the compact object at the center of our galaxy is a supermassive black hole. However, Sgr A* also shows different properties from other supermassive black holes. For example, its emission is very weak and its ability to convert matter into energy is up to hundreds of times less than in other more massive black holes. And there is still no clear evidence that it has a jet, or a flow of material that emerges from both poles at very high speed, as it happens in the brightest active galaxies.

“There is a long debate about the origin of the energy that we observe in Sgr A*: some studies suggest that its dominant radio emission is due to the accretion flow, while others indicate that it comes from a jet”, says Ilje Cho, researcher of the Institute of Astrophysics of Andalusia (IAA-CSIC) that leads the work.

But the study of Sagittarius A*, despite its proximity, is not easy: our Solar System is in the plane of the Milky Way, and in that direction there are large amounts of gas and dust. Dust limits observations to radio, infrared, and X-ray waves, which can pass through it, but still suffer from scattering from gas clouds.

Left, galactic center region observed with MeerKAT and SARAO. On the right, the results of EAVN observations at wavelengths of 1.3 and 0.7 centimeters showing the nearly circular structure of Sagittarius A*. Credit: SARAO.

SKA SARAO Meerkat Telescope (SA), 90 km outside the small Northern Cape town of Carnarvon, SA.

To resolve the fine structure of Sgr A*, the scientific team used the VLBI technique, which involves the synchronized use of numerous geographically separated radio telescopes, creating a virtual telescope the size of the distance between the telescopes. In addition, to correct for dispersion, they applied a model based on historical observations with the East Asia VLBI Network (EAVN).

East Asian VLBI Network. Credit EAVN.

“Before correcting for the effect of scattering from the interstellar medium, the structure of Sgr A* was elongated in an east-west direction. Previous studies also pointed to a similar structure, but with our work we show that the elongation comes mainly from the effect of dispersion. Three independent methods confirm that Sagittarius A* has a circular structure”, says Ilje Cho (IAA-CSIC).

The circular shape of Sgr A* would imply that the axis of rotation of the flow is almost pointing towards us (although the current data does not completely rule out the possibility that the dominant energy of Sagittarius A* comes from a jet). In addition, the team has found that, in addition to thermal energy, produced by the fall and heating of material towards the black hole, non-thermal energy is also produced, emitted by accelerated particles, perhaps by the magnetic field. “Although the mechanism of the non-thermal process has not been investigated in this study, it is important to take it into account in order to build a reliable theoretical model of how SgrA* absorbs matter,” says Ilje Cho (IAA-CSIC).

This work has also found a relationship between the size and brightness of Sgr A* and the wavelength of observation. Assuming the same relationship at shorter wavelengths, the size and brightness of Sgr A* at a wavelength of 1.3 millimeters is predicted. “This could be of great help for the analysis of data from the Event Horizon Telescope (EHT) with the aim of making the first image of the shadow of the Sagittarius A black hole, ” says Guang-Yao Zhao, a researcher at the IAA-CSIC that participates in the work. “Obtaining high-resolution images of Sgr A* is a challenge in many aspects, so the results at lower frequencies are really essential to overcome the difficulties,” adds José Luis Gómez, researcher at the IAA-CSIC and head of the group. EHT at the IAA.

AV network. Credit: IAA.

The study has been developed with the East Asia VLBI Network (EAVN), which consists of twenty-one radio telescopes: six in China, eleven in Japan and four in Korea. For this study, eighteen of them have been used to observe at wavelengths of 1.3 centimeters and 7 millimeters, respectively. The observations were carried out in April 2017, as part of the program of the Scientific Working Group on Active Galactic Nuclei of the EAVN consortium. In addition, they are part of the multi-wavelength campaign of the Event Horizon Telescope (EHT), which produced the first image of a black hole, that of the galaxy M87.

EHT map.

Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via The Event Horizon Telescope Collaboration released on 10 April 2019 via National Science Foundation(US).

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “The start of the birth of planets in a binary star system observed”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

3.10.22

Silbia López de Lacalle
Instituto de Astrofísica de Andalucía (IAA-CSIC)
Unidad de Divulgación y Comunicación
sll@iaa.es

The Institute of Astrophysics of Andalusia (IAA-CSIC) leads the study of the binary star SVS 13, still in its embryonic phase. Astronomers have observed primordial material that may be giving birth to three planetary systems around a binary star.

Models of planet formation suggest that planets form by the slow aggregation of ice and dust particles in protoplanetary disks around forming stars. Usually these models consider only single stars, such as the Sun. However, most stars form binary systems, in which two stars rotate around a common centre. Very little is yet known about how planets are born around these important twin star systems, in which the gravitational interaction between the two stars plays an essential role.

“Our results have revealed that each star has a disk of gas and dust around it and that, in addition, a larger disk is forming around both stars,” says Ana Karla Díaz-Rodríguez, a researcher at the IAA-CSIC and the UK ALMA Regional Centre (UK-ARC) at The University of Manchester, who leads the work.

Atacama Large Millimeter/submillimeter Array(CL) observations of dust in the disks around SVS13.

The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europäische Südsternwarte](EU)(CL)/National Radio Astronomy Observatory(US)/National Astronomical Observatory of Japan(JP) ALMA Observatory (CL).

The outer disk shows a spiral structure that is feeding matter into the individual disks, and in all of them planetary systems could form in the future. This is clear evidence for the presence of disks around both stars and the existence of a common disk in a binary system.

The binary system SVS 13, consisting of two stellar embryos with a total mass similar to that of the Sun, is relatively close to us, about 980 light-years away in the Perseus molecular cloud allowing its detailed study. The two stars in the system are very close to each other, with a distance of only about ninety times that between the Earth and the Sun.

The work has made it possible to study the composition of gas, dust and ionized matter in the system. In addition, nearly thirty different molecules have been identified around both protostars, including thirteen complex organic molecules precursors of life (seven of them detected for the first time in this system). “This means that when planets begin to form around these two suns, the building blocks of life will be there,” says Ana Karla Díaz-Rodríguez (IAA-CSIC / UK-ARC).

The scientific team has used the observations of SVS 13 obtained by the VLA over thirty years, together with new data from ALMA, and has followed the motion of both stars over this period, which has allowed their orbit to be traced, as well as the geometry and orientation of the system, along with many fundamental parameters, such as the mass of the protostars, the mass of the disks, and their temperature.

National Radio Astronomy Observatory(US)Karl G Jansky Very Large Array located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes.

“At the IAA we began studying this system twenty-five years ago. We were surprised when we discovered that SVS 13 was a radio binary, because only one star is seen in the optical. Normally, stellar embryos are detected in radio, but they only become visible at the end of the gestation process. It was very strange to discover a pair of twin stars where one of them seemed to have evolved much faster than the other. We designed several experiments to get more details and to find out if in such a case either of the stars could form planets. Now we have seen that both stars are very young, and that both can form planets,” says Guillem Anglada, a researcher at the Instituto de Astrofísica de Andalucía (IAA-CSIC) who is coordinating the studies of SVS 13.

SVS 13 has generated much debate in the scientific literature, as some studies consider it to be extremely young and others consider it to be in a later stage. This new study, probably the most complete study of a binary star system in formation, not only sheds light on the nature of the two protostars and their environment, but also provides crucial parameters for testing numerical simulations of the early stages of binary and multiple system formation.

Science paper:
The Astrophysical Journal

See the full article here .

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Please help promote STEM in your local schools.

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IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES): “Powerful warm winds discovered during a neutron star eruption”

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias](ES)

3.2.22

Artist’s impression of the X-ray binary Swift J1858. We see how the neutron star feeds, via an accretion disk, on the material it has stripped from the accompanying star, and how some of that material is ejected in the form of a warm wind. Credits: Gabriel Pérez Díaz, SMM (IAC).

Using the most powerful telescopes on Earth and in space, a team of astronomers has found for the first time blasts of hot, warm and cold winds from a neutron star whilst it consumes matter from a nearby star. The discovery provides new insight into the behaviors of some of the most extreme objects in the universe.

Low-mass X-ray binaries (LMXBs) are systems containing a neutron star or black hole. They are fuelled by material ripped from a neighboring star, a process known as accretion. Most accretion occurs during violent eruptions where the systems brighten dramatically. At the same time, some of the material that spirals in is propelled back into space in the form of disk winds and jets.

The most common signs of outflowing material from astronomical objects are associated with “warm” gas. Despite this, only winds of “hot” or “cold” gas have been observed in transient X-ray binaries, until now.

In this new study, a team of researchers from eleven countries, led by the University of Southampton, studied the recent eruption of the X-ray binary known as Swift J1858. They used a combination of telescopes, including NASA’s Hubble Space Telescope (HST), the European Space Agency’s XMM-Newton satellite, the European Southern Observatory Organization’s Very Large Telescope (VLT) and the Spanish Gran Telescopio Canarias (GTC)[below].

National Aeronautics and Space Administration(US)/The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Hubble Space Telescope.

The European Space Agency [La Agencia Espacial Europea] [Agencia Espacial Europea][Agence spatiale européenne][Europäische Weltraumorganisation](EU) XMM Newton X-ray Telescope.

The European Southern Observatory [La Observatorio Europeo Austral][Observatoire européen austral][Europäische Südsternwarte](EU)(CL), Very Large Telescope at Cerro Paranal in the Atacama Desert •ANTU (UT1; The Sun ) •KUEYEN (UT2; The Moon ) •MELIPAL (UT3; The Southern Cross ), and •YEPUN (UT4; Venus – as evening star). Elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

The results, published in the journal Nature, showed persistent signatures of a warm wind at ultraviolet wavelengths occurring at the same time as signatures of a cold wind at optical wavelengths. This is the first time that winds from such a system have been seen across different bands of the electromagnetic spectrum.

Lead author Dr. Noel Castro Segura, of the University of Southampton said: “Eruptions like this are rare, and each of them is unique. Normally they are heavily obscured by interstellar dust, which makes observing them really difficult. Swift J1858 was special, because even though it is located on the other side of our galaxy, the obscuration was small enough to allow for a full multiwavelength study.”

“Only one other system—the black hole X-ray binary, V404 Cyg—has shown similar properties. However, our attempt to perform the same experiment on that system was unsuccessful, because the eruption ended before we could get the ground-based and space-based telescopes to observe it simultaneously,” co-Author Dr. Hernández Santisteban from University of St Andrews said.

Swift J1858 is a newly discovered X-ray transient event that displays extreme variability across the electromagnetic spectrum, which presented a rare opportunity.

“All the astronomers in the field were incredibly excited, to the point that we combined our efforts to cover the full spectrum, from radio to X-ray using state-of-art observatories on Earth and in space,” Dr. Castro Segura continued.

Co-author Nathalie Degenaar, from the University of Amsterdam added, “Neutron stars have an immensely strong gravitational pull that allows them to gobble up gas from other stars. The stellar cannibals are, however, messy eaters and much of the gas that neutron stars pull towards them is not consumed, but flung into space at high speed. This behavior has a large impact both on the neutron star itself, and on its immediate surroundings. In this paper we report on a new discovery that provides key information about the messy eating patterns of these cosmic cookie monsters.”

“This time we had cosmic luck on our side, as we were able to co-ordinate ten telescopes and point them towards the J1858, all while it was fully active. This allows us to obtain much more information, since we can use different techniques at different wavelengths,” Dr. Hernández Santisteban said.

Dr. Degenaar added, “designing such an ambitious observing campaign—built around the best telescopes on Earth and in space—was a huge challenge. So, it is incredibly exciting that all this work has paid off and allowed us to make a key discovery that would not have been possible otherwise.”

As well as discovering the different types of winds, the team were able to study the temporal evolution of the gas that flows out. They found that the warm wind was not affected by the strong variations in the brightness of the system. The absence of such a response had previously been an unconfirmed theoretical prediction based on sophisticated simulations.

“In this research we combined the unique capabilities of the HST with the best ground-based telescopes, such as the VLT and GTC, to obtain a complete picture of the dynamics of the gas in the system, from the near-infrared to ultraviolet wavelengths. This allowed us to unveil for first time the true nature of these powerful outflows,” Dr. Castro Segura said.

“The new insights provided by our results are key to understanding how these objects interact with their environment. By shedding energy and matter into the galaxy, they contribute to the formation of new generations of stars, and to the evolution of the galaxy itself,” Dr. Castro Segura concluded.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

Roque de los Muchachos Observatory on La Palma
Teide Observatory on Tenerife.

The Instituto de Astrofísica the headquarters, which is in La Laguna (Tenerife).

Observatorio del Roque de los Muchachos at La Palma (ES) at an altitude of 2400m.

The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).

The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009; the Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope; the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

Telescopio Nazionale Galileo (IT) (ES) a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) on the island of La Palma in the Canary Islands, Altitude 2,396 m (7,861 ft).

Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft).

The Swedish 1m Solar Telescope SST at the Roque de los Muchachos observatory on La Palma Spain, Altitude 2,360 m (7,740 ft).

The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

Tiede Observatory, Tenerife, Canary Islands (ES)

Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.