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”
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.
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.
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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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.
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.
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