{"id":5248,"date":"2024-06-18T18:30:31","date_gmt":"2024-06-18T18:30:31","guid":{"rendered":"https:\/\/astronomia.udp.cl\/?p=5248"},"modified":"2024-11-12T17:31:45","modified_gmt":"2024-11-12T17:31:45","slug":"chilean-astronomers-see-a-massive-black-hole-awaken-in-real-time-claudio-ricci-and-roberto-assef-participated","status":"publish","type":"post","link":"https:\/\/astronomia.udp.cl\/en\/chilean-astronomers-see-a-massive-black-hole-awaken-in-real-time-claudio-ricci-and-roberto-assef-participated\/","title":{"rendered":"Chilean Astronomers see a massive black hole awaken in real time – Claudio Ricci and Roberto Assef participated."},"content":{"rendered":"\n
In late 2019 the previously unremarkable galaxy SDSS1335+0728 suddenly started shining brighter than ever before. To understand why, astronomers have used data from several space and ground-based observatories, including the European Southern Observatory\u2019s Very Large Telescope (ESO\u2019s VLT), to track how the galaxy\u2019s brightness has varied. In a study out today, they conclude that they are witnessing changes never seen before in a galaxy \u2014 likely the result of the sudden awakening of the massive black hole at its core.<\/h6>\n\n\n\n
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ESO SDSS1335+0728 CLAUDIO RICCI UDP – 1<\/figcaption><\/figure>\n\n\n\n

18 of June 2024<\/p>\n\n\n\n

\u201cImagine you\u2019ve been observing a distant galaxy for years, and it always seemed calm and inactive,<\/em>\u201d says Paula S\u00e1nchez S\u00e1ez, an astronomer at ESO in Germany and lead author of the study accepted for publication in Astronomy & Astrophysics. \u201cSuddenly, its [core] starts showing dramatic changes in brightness, unlike any typical events we’ve seen before.\u201d This is what happened to SDSS1335+0728, which is now classified as having an \u2018active galactic nucleus\u2019 (AGN) \u2014 a bright compact region powered by a massive black hole \u2014 after it brightened dramatically in December 2019 [1]<\/a>.<\/p>\n\n\n\n

Some phenomena, like supernova explosions or tidal disruption events \u2014 when a star gets too close to a black hole and is torn apart \u2014 can make galaxies suddenly light up. But these brightness variations typically last only a few dozen or, at most, a few hundreds of days. SDSS1335+0728 is still growing brighter today, more than four years after it was first seen to \u2018switch on\u2019. Moreover, the variations detected in the galaxy, which is located 300 million light-years away in the constellation Virgo, are unlike any seen before, pointing astronomers towards a different explanation.<\/p>\n\n\n\n

The team tried to understand these brightness variations using a combination of archival data and new observations from several facilities, including the X-shooter<\/a> instrument on ESO\u2019s VLT<\/a> in Chile\u2019s Atacama Desert [2]<\/a>. Comparing the data taken before and after December 2019, they found that SDSS1335+0728 is now radiating much more light at ultraviolet, optical, and infrared wavelengths. The galaxy also started emitting X-rays in February 2024. \u201cThis behaviour is unprecedented,\u201d says S\u00e1nchez S\u00e1ez, who is also affiliated with the Millennium Institute of Astrophysics (MAS) in Chile.<\/p>\n\n\n\n

\u201cThe most tangible option to explain this phenomenon is that we are seeing how the [core] of the galaxy is beginning to show (…) activity<\/em>,\u201d says co-author Lorena Hern\u00e1ndez Garc\u00eda, from MAS and the University of Valpara\u00edso in Chile. \u201cIf so, this would be the first time that we see the activation of a massive black hole in real time.<\/em>\u201d<\/p>\n\n\n\n

Massive black holes \u2014 with masses over one hundred thousand times that of our Sun \u2014 exist at the centre of most galaxies, including the Milky Way. \u201cThese giant monsters usually are sleeping and not directly visible<\/em>,\u201d explains co-author Claudio Ricci, from the Diego Portales University, also in Chile. \u201cIn the case of SDSS1335+0728, we were able to observe the awakening of the massive black hole, [which] suddenly started to feast on gas available in its surroundings, becoming very bright.<\/em>\u201d<\/p>\n\n\n\n

\u201c[This] process (…) has never been observed before<\/em>,\u201d Hern\u00e1ndez Garc\u00eda says. Previous studies reported inactive galaxies becoming active after several years, but this is the first time the process itself \u2014 the awakening of the black hole \u2014 has been observed in real time. Ricci, who is also affiliated with the Kavli Institute for Astronomy and Astrophysics at Peking University, China, adds: \u201cThis is something that could happen also to our own Sgr A*, the massive black hole (…) located at the centre of our galaxy<\/em>,” but it is unclear how likely this is to happen. <\/p>\n\n\n\n

Follow-up observations are still needed to rule out alternative explanations. Another possibility is that we are seeing an unusually slow tidal disruption event, or even a new phenomenon. If it is in fact a tidal disruption event, this would be the longest and faintest such event ever observed. \u201cRegardless of the nature of the variations, [this galaxy] provides valuable information on how black holes grow and evolve<\/em>,\u201d S\u00e1nchez S\u00e1ez says. \u201cWe expect that instruments like [MUSE on the VLT or those on the upcoming Extremely Large Telescope (ELT)] will be key in understanding [why the galaxy is brightening<\/em>].\u201d  <\/p>\n\n\n\n

Notes<\/strong><\/p>\n\n\n\n

[1] The SDSS1335+0728 galaxy\u2019s unusual brightness variations were detected by the Zwicky Transient Facility (ZTF) telescope in the US. Following that, the Chilean-led Automatic Learning for the Rapid Classification of Events (ALeRCE) broker classified SDSS1335+0728 as an active galactic nucleus.<\/p>\n\n\n\n

<\/a>[2] The team collected archival data from NASA\u2019s Wide-field Infrared Survey Explorer (WISE) and Galaxy Evolution Explorer (GALEX), the Two Micron All Sky Survey (2MASS), the Sloan Digital Sky Survey (SDSS), and the eROSITA instrument on IKI and DLR\u2019s Spektr-RG space observatory. Besides ESO\u2019s VLT, the follow-up observations were conducted with the Southern Astrophysical Research Telescope (SOAR), the W. M. Keck Observatory, and NASA\u2019s Neil Gehrels Swift Observatory and Chandra X-ray Observatory.<\/p>\n\n\n\n

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