From IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “Dust in the central parsecs of unobscured AGN provide more challenges to the torus”

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

04/09/2021

M Almudena, Prieto Escudero, J. Nadolny
Instituto de Astrofísica de Canarias (IAC)

J. A. Fernández-Ontiveros
Istituto di Astrofisica e Planetologia Spaziali (IT)

M. Mezcua
Institute of Space Studies of Catalonia [Institut d’Estudis Espacials de Catalunya](ES)

The image shows the process of nuclear feeding of a black hole in the galaxy NGC 1566, and how the dust filaments – seen in white-blue colors- are trapped and rotating in a spiral around the black hole until the black hole swallows them. Credit: ESO.

The black holes at the centres of galaxies are the most mysterious objects in the Universe, not only because of the huge quantities of material within them, millions of times the mass of the Sun, but because of the incredibly dense concentration of matter in a volume no bigger than that of our Solar System. When they capture matter from their surroundings they become active, eventually giving rise to the ejection of huge amounts of energy. It is however difficult to detect the black hole during these capture episodes because the event is rare. We detected long and narrow dust filaments surrounding and feeding the black hole in the centres of several galaxies. These filaments could furthermore be the natural cause of the darkening of the centre of many galaxies when their nuclear black holes become active. The discovery of these filaments and the understanding of their nature have been made possible by using extremely sharp images obtained with the Hubble Space Telescope, the Very Large Telescope (VLT) at the European Southern Observatory (ESO), and the Atacama Large Millimetre Array (ALMA) in Chile.

National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU) Hubble Space Telescope

European Southern Observatory(EU) , 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.

[Observatoire européen austral][Europäische Südsternwarte] (EU)/National Radio Astronomy Observatory(US)/National Astronomical Observatory of Japan(JP) ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

Each of these images provides us with a different view of the various states of the interstellar medium in which these filaments reside. Their combined analysis led to a direct visualisation of filaments feeding the black hole. A first estimate of the amount of matter in the filaments indicates an inflow equivalent to the mass of the Sun per year.

Science paper:
MNRAS

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 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 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.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “Anatomy of the impact of a protostellar jet in the Orion Nebula”

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

02/09/2021

View of HH204-a Herbig-Haro object in the Orion Nebula. The left panel shows the Orion Nebula observed with the Hubble Space Telescope, picking out the area around HH204. In the right panel, we can see in detail the structure of HH204 and of its apparent companion, HH203. In this panel, the images by the Hubble Space Telescope taken during 20 years and artificially highlighted with different colours show the advance of the jets of gas through the Orion Nebula. Credit: Gabriel Pérez Díaz, SMM (IAC).

An international team led by researchers from the Instituto de Astrofísica de Canarias (IAC) has uncovered, with an new high degree of detail, the physical and chemical effects of the impact of a protostellar jet in the interior of the Orion Nebula. The study was made using observations with the Very Large Telescope (VLT) and 20 years of images with the NASA/ESA Hubble Space Telescope (HST).

European Southern Observatory(EU) , 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.

National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU) Hubble Space Telescope

The observations show evidence of compression and heating produced by the shock front, and the destruction of dust grains, which cause a dramatic increase in the gas phase abundance of the atoms of iron, nickel, and other heavy elements in the Orion Nebula. The results were recently published in The Astrophysical Journal.

The Orion Nebula, one of the known and brightest objects in the night sky, is the nearest region of massive star formation to Earth, and it has a complex and extensive gas structure.

In one of the most detailed astronomical images ever produced, NASA ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope.

Orion Nebula ESO/VLT

Some of the newborn stars within it emit jets of gas at high speed which, when they impact their surroudings, produce shock fronts which compress and heat the nebular gas. These impact zones are bow-shaped, and are called Herbig-Haro objects, after their discoverers, the US astonomer George Herbig, and the Mexican astronomer Guillermo Haro.

These objects have been observed previously in many dark nebulae, where the cold gas is neutral, and its main source of energy is the heat generated by the shock. However, the jets of gas in the Orion Nebula are immersed in a large radiation field produced by the most massive stars in the Trapezium of Orion, situated at the centre of the nebula. Due to this radiation the gas within the shock front and also the gas compressed after it has passed through, is warm and ionized, and this allows us to measure precisely the physical conditions and the chemical composition of the jet.

The research carried out by a team of astronomers in Spain, Mexico and the United States, led by José Eduardo Méndez Delgado, a doctoral student at the IAC and the University of La Laguna [Universidad de La Laguna](ES), has uncovered the complex relations between the ionic abundances of the gas and its physical conditions in HH204, one of the most prominent Herbig-Haro objects in the Orion Nebula.

“Our work shows that the in the shock front of HH204 the gas abundances of heavy elements such as iron and nickel are increased by up to 350% compared to the values usually found in the Orion Nebula, and this allows us to determine the proportion of other chemical elements more accurately, which contributes to an improved knowledge of the chemical evolution in the solar neighbourhood”, explains José Eduardo Méndez Delgado, the first author of the article.

“As well as the heavy element enrichment in the gas phase, we have observed a heated post-shock zone which comprises a very small fraction of the gas, and which lets us understand the different layers of the structure of the Herbig-Haro object generated by the impact of the shock front”, says César Esteban, and IAC researcher and a co-author of the article.

“The origin of HH204 appears to be associated with one of the most brilliant and star formation rich zones of the Orion Nebula, the regions called Orion South, although there are many interactions of gas which appear to feed it from several directions”, adds William Henney, a researcher at the Institute of Radioastronomy and Astrophysics at the The National Autonomous University of Mexico [Universidad Nacional Autónoma de México](MX), and a co-author of the article.

“Thanks to the images of the Hubble Space Telescope we have shown that HH204 is propagating at an angle of 32º with the plane of the sky, which lets us observe the compression of the gas transversely as we approach the shock front”, points out Karla Arellano Córdova, a researcher at The University of Texas-Austin (US), and a co-author of the article.

“We have seen that the impact of these objects can be important when determining the local physical conditions in ionized nebulae. In fact, if we don’t take these effects into account we can make incorrect determinations of the chemical composition of the ionized nebulae, which are fundamental techniques for understanding the chemical evolution of the Universe”, sums up Jorge García Rojas, an IAC researcher and a co-author of the article.

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 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 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.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “IRSOL and IAC scientists solve a complex paradox in solar physics”

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

18/08/2021

Image of the solar atmosphere showing a coronal mass ejection. Credit: National Aeronautics Space Agency (US)/SDO.

NASA Solar Dynamics Observatory

In 1998, the journal Nature published a seminal letter concluding that the mysterious polarization signal that had been recently discovered in the light emitted by the sodium atoms of the solar atmosphere implies that the solar chromosphere (a very important layer of the solar atmosphere) is practically unmagnetized, in sharp contradiction with common wisdom. This paradox motivated laboratory experiments and theoretical investigations, which instead of providing a solution, raised new issues and even led some scientists to question the quantum theory of radiation-matter interaction. In an article published and highlighted today by the prestigious Physical Review Letters, Ernest Alsina Ballester (IRSOL and IAC), Luca Belluzzi (IRSOL) and Javier Trujillo Bueno (IAC) show the solution to such intriguing paradox, which has puzzled solar physicists over the last decades. This research opens up a new window for exploring the elusive magnetic fields of the solar chromosphere in the present new era of large-aperture solar telescopes.

Twenty-five years ago, an enigmatic signal was discovered while analyzing the polarization of sunlight with a new instrument, the Zurich Imaging Polarimeter (ZIMPOL) [Nature]. This mysterious linear polarization signal appears at the 5896 Å wavelength of the D1 line of neutral sodium where, according to the line’s quantum numbers, no linear polarization due to scattering processes should be present. This polarization signal was therefore totally unexpected, and its interpretation immediately opened an intense scientific debate. The mystery further increased two years later, when the journal Nature published a letter with an explanation, which required that the sublevels of the lower level of the D1 line are not equally populated. In that theoretical work, the enigmatic polarization signal of the D1 line was reproduced remarkably well. However, the proposed explanation implied that the region of the solar atmosphere known as the chromosphere is completely unmagnetized, in apparent contradiction with established results, which instead indicate that the quiet regions (outside sunspots) of the solar chromosphere are permeated by magnetic fields in the gauss range. This opened a serious paradox, which has challenged solar physicists for many years, and even led some scientists to question the quantum theory of atom-photon interactions.

A first breakthrough towards the resolution of the paradox was achieved in 2013 at the IAC, when Luca Belluzzi and Javier Trujillo Bueno theoretically discovered a new mechanism through which linear polarization can be produced in the sodium D1 line without the need of population imbalances in the lower level of the D1 line. However, that important step given by these researchers was for the idealized case of a solar atmosphere model without magnetic fields.

Figure 1: Variation with wavelength of the linear polarization (Q/I) of sunlight across the solar sodium D1 and D2 spectral lines (left panel) and across D1 (right panel). The black curves indicate the observed signals (the measurements were carried out at IRSOL with the ZIMPOL instrument). The red and blue curves show the results of theoretical calculations carried out neglecting (red) and including (blue) magnetic fields. An excellent agreement between the observation and the theoretical modeling is obtained when assuming that the quiet regions (outside sunspots) of the solar chromosphere are permeated by a magnetic field of 15 gauss.

In an article published today by Physical Review Letters, the prestigious scientific journal of the American Physical Society, Ernest Alsina Ballester, Luca Belluzzi, and Javier Trujillo Bueno show the solution to this intriguing paradox, which has puzzled solar physicists since 1998. As shown in figure 1, this team of researchers has been able to reproduce the enigmatic observations of the D1 line polarization, in the presence of magnetic fields in the gauss range. To achieve this result, it was necessary to carry out the most complete theoretical modeling of this polarization signal ever attempted, accounting for the joint action of very complex physical mechanisms. This required three years of work, carried out through a close cooperation between the Istituto Ricerche Solari (IRSOL) in Locarno-Monti (affiliated to the Università della Svizzera italiana) and the POLMAG group of the Instituto de Astrofísica de Canarias (IAC) in Tenerife (see http://research.iac.es/proyecto/polmag/).

This result has very important consequences. Linear polarization signals, like the one observed in the D1 line of sodium, are extremely interesting because they encode unique information on the elusive magnetic fields present in the solar chromosphere. This key interface layer of the solar atmosphere, located between the underlying cooler photosphere and the overlying million-degree corona, is at the core of several enduring problems in solar physics, including the understanding and prediction of the eruptive phenomena that may strongly impact our technology-dependent society. The magnetic field is known to be the main driver of the spectacular dynamical activity of the solar chromosphere, but our empirical knowledge of its intensity and geometry is still largely unsatisfactory. The solution of the long-standing paradox of solar D1 line polarization proves the validity of the present quantum theory of spectral line polarization, and opens up a new window to explore the magnetism of the solar atmosphere in the present new era of large-aperture solar telescopes.

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 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 William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

[caption id="attachment_72536" align="alignnone" width="632"] Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “A nonlinear damping mechanism for waves in the solar corona”

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

17/08/2021

Scatter plot of oscillation amplitude and damping ratio values for 101 loop oscillation cases. The symbols and their colors indicate the levels of evidence obtained for the nonlinear (NL) and the linear resonant absorption (RA) models.

The solar coronal heating problem originated almost 80 years ago and remains unsolved. A plausible explanation lies in mechanisms based on magnetic wave energy dissipation. Currently, several linear and nonlinear wave damping models have been proposed. The advent of space instrumentation has led to the creation of catalogues containing the properties of a large number of loop oscillation events. When the damping ratio of the oscillations is plotted against their oscillation amplitude, the data are scattered forming a cloud with a triangular shape. Larger amplitudes correspond in general to smaller damping ratio values and vice versa. Here, a Bayesian model comparison analysis has quantified the evidence for a nonlinear damping model relative to the evidence for linear resonant absorption in explaining the observed damping of coronal loop oscillations. The results indicate that there is qualitative agreement between the regions of high marginal likelihood and Bayes factor for the nonlinear damping model and the arrangement of observed data. A quantitative application to 101 loop oscillation cases observed with the Solar Dynamics Observatory (SDO, NASA) results in the marginal likelihood for the nonlinear model being larger in the majority of them. Moreover, the cases with conclusive evidence for the nonlinear model outnumber considerably those in favor of linear resonant absorption. Nonlinear damping is therefore a plausible explanation for the observed damping of solar coronal waves.

Science paper:
The Astrophysical Journal Letters

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 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 William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

[caption id="attachment_72536" align="alignnone" width="632"] Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “Astronomers discover how to feed a black hole”

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

29/07/2021

The image shows the process of nuclear feeding of a black hole in the galaxy NGC 1566, and how the dust filaments, which surround the active nucleus, are trapped and rotate in a spiral around the black hole until it swallows them. Credit: European Southern Observatory [Observatoire européen austral][Europäische Südsternwarte] (EU) (CL).

The black holes at the centres of galaxies are the most mysterious objects in the Universe, not only because of the huge quantities of material within them, millions of times the mass of the Sun, but because of the incredibly dense concentration of matter in a volume no bigger than that of our Solar System. When they capture matter from their surroundings they become active, and can send out enormous quantities of energy from the capture process, although it is not easy to detect the black hole during these capture episodes, which are not frequent.

However, a study led by the researcher Almudena Prieto, of the Instituto de Astrofísica de Canarias (IAC), has discovered long narrow dust filaments which surround and feed these black holes in the centres of galaxies, and which could be the natural cause of the darkening of the centres of many galaxies when their nuclear black holes are active. The results of this study have recently been published in the journal MNRAS.

Using images from the Hubble Space Telescope, the Very Large Telescope (VLT) at the European Southern Observatory (ESO), and the Atacama Large Millimetre Array (ALMA) in Chile, the scientists have been able to obtain a direct visualization of the process of nuclear feeding of a black hole in the galaxy NGC 1566 by these filaments. The combined images show a snapshot in which one can see how the dust filaments separate, and then go directly towards the centre of the galaxy, where they circulate and rotate in a spiral around the black hole before being swallowed by it.

National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU) Hubble Space Telescope

European Southern Observatory(EU) , 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.

European Southern Observatory [Observatoire européen austral][Europäische Südsternwarte] (EU)/National Radio Astronomy Observatory(US)/National Astronomical Observatory of Japan(JP) ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

“This group of telescopes has given us a completely new perspective of a supermassive black hole, thanks to the imaging at high angular resolution and the panoramic visualization of its surroundings, because it lets us follow the disappearance of the dust filaments as they fall into the black hole”, explains Almudena Prieto, the first author on the paper.

The study is the result of the long-term PARSEC project of the IAC, which aims to understand how supermassive black holes wake up from their long lives of hibernation, and after a process in which they accrete material from their surroundings, they become the most powerful objects in the Universe.

Part of this work was carried out within the Master’s thesis in Astrophysics of the University of La Laguna [Universidad de La Laguna](ES) of Jakub Nadolny, carried out at the IAC within the PARSEC project. Researchers Mar Mezcua and Juan A. Fernández Ontiveros were also advisers to this work, while they had PARSEC postdoctoral contracts at the IAC.

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 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 William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

[caption id="attachment_72536" align="alignnone" width="632"] Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “Three dwarf spheroidal galaxies are found to rotate”

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

27/07/2021
Alberto Manuel Martínez-García
ammtnez@iac.es

Fornax dwarf spheroidal galaxy. Credit: European Southern Observatory [Observatoire européen austral][Europäische Südsternwarte] (EU) (CL)/Digitized Sky Survey 2.

An international team of astrophysicists from the Instituto de Astrofísica de Canarias (IAC), the University of La Laguna [Universidad de La Laguna](ES) and the Space Telescope Science Institute (US) has discovered the presence of transverse rotation (in the plane of the sky) in three dwarf spheroidal galaxies, a very faint type of galaxies and difficult to observe, which are orbiting round the Milky Way; this helps to trace their evolutionary history. The finding was made using the most recent data from the GAIA satellite of the European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU).

European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) GAIA satellite

Carina Dwarf Galaxy.The image was made using observations from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at La Silla, and from the Victor M. Blanco 4-metre telescope at the Cerro Tololo Inter-American Observatory.

Wide Field Imager on the 2.2 meter MPG/ESO telescope at Cerro LaSilla (CL)

MPG Institute for Astronomy [Max-Planck-Institut für Astronomie](DE)European Southern Observatory(EU)2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

European Southern Observatory [Observatoire européen austral][Europäische Südsternwarte](EU) (CL)La Silla_Observatory 600 km north of Santiago de Chile at an altitude of 2400 metres.

NOIRLab National Optical Astronomy Observatory(US) Cerro Tololo Inter-American Observatory(CL) Victor M Blanco 4m Telescope which houses the Dark-Energy-Camera – DECam at Cerro Tololo, Chile at an altitude of 7200 feet

NSF NOIRLab NOAO (US) Cerro Tololo Inter-American Observatory(CL) approximately 80 km to the East of La Serena, Chile, at an altitude of 2200 meters.

PGC 621 (Sculptor Dwarf Irregular Galaxy). NASA/ESA Hubble.

National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU) Hubble Space Telescope

The results of the study have just been published in the journal MNRAS.

Dwarf galaxies have a particular interest for cosmology. The standard cosmological model suggests that this type of galaxies was the first to form. Many of them, the majority, have been destroyed and cannibalized by large galaxies such as the Milky Way. However, those that remain can be studied and contain valuable information about the early Universe.

One subclass of dwarf galaxies are the dwarf spheroidals. They are very diffuse, with low luminosity, they contain large proportions of dark matter and little or no gas. Since their discovery they have been deeply studied. However, their internal kinematics are still little known, due to the technical difficulties needed for their detailed study.

Various previous studies have shown that the dwarf spheroidals do not have patterns of internal rotation, but their stars move on random orbits predominantly towards and away from the centre of the galaxy. But the galaxies within the other major sub-class of dwarfs, the irregulars, have large quantites of gas, and in some cases do have internal rotation. These differences suggest a different origin for the two types of dwarfs, or to a very different evolutionary history in which interactions with large galaxies, in our case with the Milky Way, have played a crucial role in eliminating the internal rotation of the spheroidals.

To carry out their present research, the team of astrophysicists form the IAC and the STScI have used the latest data from ESA’s Gaia to study the internal kinematics of six dwarf spheroidal galaxies, satellites of the Milky Way, and have discovered the presence of transverse rotation (in the plane of the sky) in three of them: Carina, Fornax, and Sculptor. These are the first detections of this type of rotation in dwarf spheroidal galaxies, except for the Sagittarius spheroidal, which is strongly distorted by the gravitational potential of the Milky Way, and is therefore not representative of its type.

“The importance of this result is because, in general, the internal kinematics of galaxies, in this case their rotation, is an important tracer of their evolutionary history, and of the conditions in which the system was formed”, explains Alberto Manuel Martínez-García, doctoral student at the IAC and the ULL, and first author of the article.

“Although the standard model of cosmology assumes that the dwarf galaxies were the first to form, it is not clear if they are simple systems or whether those we observe are formed by the agglomeration of other even simpler systems, smaller and older. The presence of rotation suggests the second option. It also suggests a common origin for all dwarf galaxies, those that are at present rich in gas (the irregulars) and those which are not (the spheroidals)”, explains Andrés del Pino, researcher at the STScI and a co-author of the article.

“The Gaia satellite has revolutionised our knowledge of the Milky Way and its neighbourhood, giving us very precise measurements of the positions and motions of almost two thousand million stars. Although the data from Gaia are used mainly to study our Galaxy, this ESA mission has also opened a new window on the study of the satellite galaxies of the Milky Way, giving specific access to their internal kinematics”, says Antonio Aparicio, a researcher at the IAC and the ULL and a co-author of the article.

Even so, according to the researchers, studies based on Gaia data entail many technical difficulties. In the first place, one must determine which of the stars in the database really belong to the satellite galaxies, and which to the Milky Way itself, as the latter tend to contaminate the sample. The problem is that although the data to be analysed are limited to the region and the angular size of the spheroidal under study, which is the equivalent of one quarter of the angular diameter of the Moon, the vast majority of the stars detected in this area belong to the Milky Way and therefore indeed contaminate the sample.

In addition, the distance of the spheroidals studied, which is up to some half a million light-years, and the low intrinsic luminosity of their stars, imply that the measurements are affected by a considerable level of noise. For all these reasons the analysis of the data requires a thorough filtration and a deep analysis of the different observational parameters to be able to reach reliable conclusions.

Members of the research team involved in this study, which forms a part of the doctoral thesis of Alberto Manuel Martínez-García, include Andrés del Pino Molina (STScI, director of the thesis), Antonio Aparicio Juan (IAC-ULL, director of the thesis), Roeland P. van der Marel (STScI, Center for Astrophysical Sciences, at the Johns Hopkins University (US)) and Laura L. Watkins (ESA mission to Association of Universities for Research in Astronomy (US), STScI).

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 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 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.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “WEAVE is ready to start operating in La Palma”

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

22/07/2021

All the main components of the new multiobject spectrograph WEAVE on the William Herschel Telescope (WHT) in the Roque de los Muchachos Observatory (Garafía, La Palma) have arrived on the island.

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

The Instituto de Astrofísica de Canarias (IAC) has played an outstanding role in the design and production of the parts of this instrument, the work of an international collaboration, which will start its commissioning after immediate integration on the telescope.

WEAVE’s fibre positioner after being unpacked at the William Herschel Telescope (WHT). Credit: Isaac Newton Group of Telescopes (ING), La Palma.

WEAVE’s spectrograph installed at the WHT. Credit: NOVA.

The WEAVE (William Herschel Telescope Enhanced Area Velocity Explorer) spectrograph, will widen the field of view of the telescope to two degrees on the sky, four times the apparent diameter of the Moon, which will allow it to observe up to a thousand astronomical objects at a time during night-time observations; these will be carried out for the next five years. It will also allow scientists to follow the sources observed in the Gaia space mission of the European Space Agency (ESA) and study objects from white dwarfs close to the Sun to the host galaxies of sources of gravitational waves.

Scott Trager, researcher at the Kapteyn Astronomical Institute, University of Groningen [Rijksuniversiteit Groningen] (NL) and project scientist on the WEAVE Survey Consortium expressed his satisfaction at reaching this important milestone: “WEAVE will give tens of millions of spectra of stars and galaxies during the next five years, and its survey will yield data which will help to answer questions such as the formation of the galaxies, including the Milky Way and its stars, and about the nature of dark matter and dark energy”.

WEAVE has been designed and developed by a large team of technicians and scientists in Spain; the United Kingdom; the Netherlands; France; Italy; Hungary; and Mexico. Gavin Dalton, Principal Investigator on Weave, from the University of Oxford (UK) and of the Science and Technology Facilities Council‘s RAL Space (UK), says: “It is most exciting to see the sustained efforts of so many people united at the telescope, and at last to be able to set working the positioning system. WEAVE has required ten years of development, with many complex moving pars, and components developed in laboratories throughout Europe. As a result, at the Roque de los Muchachos Observatory we are about to offer astronomers a new and improved way to look at the stars”.

The Instituto de Astrofísica de Canarias is a member of the WEAVE consortium from the start, and has taken charge of supplying important instrumental packages for the full instrument. The main components of WEAVE provided by the Instituto de Astrofísica de Canarias have been the field rotator, designed and made in collaboration with the IDOM company (Spain) and the prime focus corrector, designed in collaboration with the Isaac Newton Group of Telescopes (ING) with the support of the Konkoly Observatory of the Hungarian Academy of Sciences [ Konkoly Thege Miklós Csillagászati Intézet](HU), and manufactured by the SENER aerospace company (Spain). In addition, the IAC has given its support to the development of the fibres positioner and the spectrograph, as well as the development of software for the analysis of the data from WEAVE.

According to José Alfonso López Aguerri, the Principal Investigator for WEAVE in the IAC, “the WEAVE project has permitted Spanish companies to obtain know-how in front-line technologies which will let them opt for contracts in major future scientific projects. It has been a pleasure to work with a great technical team to complete the instrumental packages which we were assigned within the consortium”.

Commissioning WEAVE will start after the instrument has been integrated and will last between two and three months, after which there will be observations for science verification, followed by routine observations and open time. The first assignations of open time have already been awarded. They are part of an International Time Project (ITP) and an announcement of opportunity for open time will be published once the commissioning of the instrument has been completed.

For Marc Balcells, the Director of the Isaac Newton Group of Telescopes (ING), “the ING initiated the project to build WEAVE after a wide consultation of the international community which used the observatory. Our vision is to guarantee that the WHT will continue to supply the astronomers with the data they need to answer some of the most pressing current problems about the Universe. It has been exciting to build some of the parts of WEAVE, with the strong support of the STFC, and to start the tests, now that the hardware is being set up and made ready. We really want to use it on the sky and to start scientific research with it in a few months”.

The Spanish astronomical community has been interested from the beginning of the project in the capacities and in the science which WEAVE will produce. In particular, some 60 Spanish astronomers from different institutions have been active in the design of the astronomical surveys which WEAVE will carry out in the next five years. Several of these surveys will be led by IAC researchers.

For Jesús Falcón Barroso, Principal Investigator of the WEAVE-Aperif survey, “WEAVE opens a unique window to explore the Universe. The large surveys of stars and galaxies which will be made will give a radically different view, not only of our own Galaxy but of tens of thousands of galaxies at cosmological distances. This will let us tackle some key problems in Astrophysics, such as the formation and evolution of the Milky Way, or the effects of environment in the transformation and the evolution of galaxies in general. WEAVE represents the best laboratory to unveil the physical mechanisms which govern the formation of structures on different scales in the Universe”.

More information can be found in the press release from the Isaac Newton Group of Telescopes (ING): http://www.ing.iac.es/PR/press/weave_july_2021.html

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 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 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.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “A large tidal stream observed in the Sombrero galaxy”

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

21/07/2021

Sombrero galaxy. Credits: National Aeronautics Space Agency (US) and the Hubble Heritage Team (Space Telescope Science Institute (US)/ Association of Universities for Research in Astronomy (US) (US))

According to the latest cosmological models, large spiral galaxies such as the Milky Way grew by absorbing smaller galaxies, by a sort of galactic cannibalism. Evidence for this is given by very large structures, the tidal stellar streams, which are observed around them, which are the remains of these satellite galaxies. But the full histories of the majority of these cases are hard to study, because these flows of stars are very faint, and only the remains of the most recent mergers have been detected.

A study led by the Institute of Astrophysics of Andalusia [Instituto de Astrofísica de Andalucía] (ES), with the participation of the Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias] (ES), has made detailed observations of a large tidal flow around the Sombrero galaxy, whose strange morphology has still not been definitively explained. The results are published today in the journal MNRAS.

The Sombrero galaxy (Messier 104) is a galaxy some thirty million light years away, which is part of the Local Supercluster (a group of galaxies which includes the Virgo cluster and the Local Group containing the Milky Way).

Local Group. Andrew Z. Colvin 3 March 2011

It has roughly one third of the diameter of the Milky Way, and shows characteristics of both of the dominant types of galaxies in the Universe, the spirals and the ellipticals. It has spiral arms, and a very large bright central bulge, which makes it look like a hybrid of the two types.

“Our motive for obtaining these very deep images of the Sombrero galaxy (Messier 104) was to look for the remains of its merger with a very massive galaxy. This possible collision was recently suggested on the basis of studies of the stellar population of its strange halo obtained with the Hubble Space Telescope”, says David Martínez-Delgado, a researcher at the IAA-CSIC and first author of the paper reporting the work.

National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU) Hubble Space Telescope

The observations with the Hubble, in 2020, showed that the halo, an extensive and faint region surrounding the Sombrero galaxy, shows many stars rich in metals, elements heavier than hydrogen and helium. This is a feature typical of new generations of stars, which are normally found in the discs of galaxies, and are quite unusual in galactic halos, which are populated by old stars. To explain their presence astronomers suggested what is known as “a wet merger”, a scenario in which a large elliptical galaxy is rejuvenated by large quantities of gas and dust from another massive galaxy, which went into the formation of the disc which we now observe.

“In our images we have not found any evidence to support this hypothesis, although we cannot rule out that it could have happened several thousand million years ago, and the debris is completely dissipated by now -explains David Martínez-Delgado-. In our search we have in fact been able to trace for the first time the complete tidal stream which surrounds the disc of this galaxy, and our theoretical simulations have let us reconstruct its formation in the last three thousand million years, by cannibalism of a satellite dwarf galaxy”.

“Observational techniques in present day Astrophysics need advanced image processing. Our modelling of the bright stars around the Sombrero galaxy, and at the same time of the halo light of the galaxy itself has enabled us to unveil the nature of this tidal stream. It is remarkable that thanks to these advanced photometric techniques we have been able to do front line science with a Messier object using only an 18 cm (diameter) telescope”, explains Javier Román, a postdoctoral researcher at the IAC and a co-author of the study.

The research team rejects the idea that the large stellar tidal stream, known for more than three decades, could be related to the event which produced the strange morphology of the Sombrero galaxy which, if it was caused by a wet merger, would need the interaction of two galaxies with large masses.

The work has been possible thanks to the collaboration between professional and amateur astronomers. “We have collaborated with the Spanish astrophotographer Manuel Jiménez, who took the images with a robotic telescope of 18 centimetre diameter, and the well-known australian astrophotographer David Malin, who discovered this tidal stream on photographic plates taken in the 90’s of the last century. This collaboration shows the potential of amateur telescopes to take deep images of nearby galaxies which give important clues about the process of their assembly which is continuing until the present epoch”, concludes Martínez-Delgado.

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 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 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.

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 Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “CARMENES instrument finds two new planetary systems formed by Earths and super-Earths”

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

30/06/2021

The Institute of Astrophysics of Andalusia (IAA-CSIC) leads the detection of what, according to the data, is the most common type of planetary systems around dwarf stars, the most common in the Milky Way.

The era of the detection of planets outside our Solar System, which began less than three decades ago, has so far yielded more than four thousand detected planets. Their astonishing variety has shown that the structure of our Solar System, with rocky planets in the inner regions and gaseous icy planets in the outer regions, is not as typical as previously thought, and that other configurations appear more common, such as gas giant planets very close to their stars or systems with several super-Earths around dwarf stars. In this context, a new detection of two planetary systems by the CARMENES instrument, operating at Calar Alto Observatory (CAHA, Almería), reinforces the idea that dwarf stars tend to harbour rocky planets.

CARMENES spectrograph, mounted on the Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres.

The 3.5-metre telescope at Calar Alto Observatory, where the CARMENES instrument operates.

Calar Alto Astronomical Observatory 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres(ES)

“Our current understanding of the formation of low-mass planets in orbits very close to small stars suggests that they are very abundant, with an average of at least one planet per star. Despite this abundance, we hardly have any data on the density of these planets that would allow us to deduce their composition,” says Pedro J. Amado, a researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) who heads the study.

In our Solar System, Earth, Mars, Mercury and Venus are categorised as terrestrial or rocky planets. For extrasolar planets, those between half and twice the size of Earth are considered to be terrestrial, while those up to ten times the mass of Earth are classified as super-Earths, terms that have no implications for surface conditions or habitability. In fact, while the composition of Earth-like exoplanets may be similar to that of the rocky planets in the Solar System, the composition of super-Earths may also include other combinations of gas, rock, ice or water.

The newly detected systems are found around the red dwarf (or M-dwarf) stars G 264-012 and Gl 393. Two planets with a minimum mass of 2.5 and 3.8 times that of the Earth have been found around the former, orbiting their star every 2.3 and 8.1 days. The planet in Gl 393 has a minimum mass of 1.7 Earth masses and orbits its star every seven days. All three planets fall into the category of hot earths and super-earths, and reach temperatures that preclude the presence of liquid water on the surface.

“To understand how the different planetary systems we are observing form and evolve, we need robust statistics on the number of planets that exist, as well as information on the architecture of the systems and the density of the planets. This will allow us to explain those that do not fit the known mechanisms, such as the GJ 3512 system that we also found with CARMENES, which has a giant planet around a dwarf star, or to confirm the tendency of dwarf stars to host multiple systems,” says Pedro J. Amado (IAA-CSIC).

In this sense, this work has also made it possible to detect a new factor that seems to influence the detections, since the planet around the star Gl 393 had gone unnoticed in previous campaigns with highly efficient planet-hunting instruments. Red dwarf stars show intense activity in the form of flares that can mask the signal from potential planets, and the research team noted that the non-detection of Gl 393’s planet could be due to the fact that previous observations were carried out during a peak of activity. They concluded that planets can most easily be detected in dwarf stars with moderate activity or outside the peaks of the star’s activity cycle.

“The CARMENES work is focused on extending the available data to compose a global picture of the planetary systems. The three planets in these two systems are among the smallest in mass, and therefore in the amplitude of the radial velocity they instill in their stars, which accounts for the quality of the instrument,” concludes Pedro J. Amado (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 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 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.

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 Manu Garcia- a friend from IAC via IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “Discovering the hidden black holes”

From Manu Garcia- a friend from IAC.

via

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

Artist’s illustration depicting a black hole engulfed in a donut-shaped or toroidal cocoon of gas and dust. Viewed from the edge as in this illustration, the cocoon protects our view from the hot disk of matter falling onto the black hole, as well as the associated fast-moving material that is ejected from the disk. The low-energy, visible X-ray light from the central region is almost completely hidden, while the high-energy X-rays seen by NuSTAR are more penetrating and detectable. Viewed from the front, such as from above or below, the central region is visible in all energies. In this illustration, a part of the cocoon is cut out to show the very darkened black hole. Understanding the geometry and properties of this darkening region has important implications for understanding how supermassive black holes, and the galaxies in which they reside, grow, and evolve over cosmic time.
(Credit: M.Weiss/ National Aeronautics Space Agency (US) /Chandra X-ray Center (US).

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

In a recent paper published in The Astrophysical Journal, Elias Kammoun and his collaborators used NuSTAR to study a carefully selected sample of 19 nearby galaxies with faint evidence of supermassive black holes actively accumulating at their centers.

National Aeronautics and Space Administration(US),Technical University of Denmark [Danmarks Tekniske Universite](DK),ASI Italian Space Agency [Agenzia Spaziale Italiana](IT) NuSTAR X-ray telescope .

Like the insect census worker trying to understand the firefly population in a small part of his backyard, Kammoun and his collaborators used NuSTAR to understand whether their sample of nearby galaxies was weak because their black holes were inherently faint or whether Instead, they were intrinsically luminous. black holes shrouded behind thick curtains of gas and dust.

See the full article here .

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much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.

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

The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

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

Roque de los Muchachos Observatory | Instituto de Astrofísica de Canarias • IAC(ES)

Tiede Observatory, Tenerife, Canary Islands (ES)

These centres, with all the facilities they bring together, make up the European Northern Observatory (EU).

The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna [Universidad de La Laguna](ES) and Spanish National Research Council [Consejo Superior de Investigaciones Científicas] (ES) (CSIC).

The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

The IAC’s research programme includes astrophysical research and technological development projects.

The IAC is also involved in researcher training, university teaching and outreach activities.

The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.