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Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Six captive galaxies undergoing sudden, dramatic transitions

Six captive galaxies undergoing sudden, dramatic transitions



  Low-ion nuclear emission galaxies

A new study led by astronomers at the University of Maryland documents six sleepy low-ion nuclear emission galaxies (LINERs above) suddenly transformed into quasi-transformative images below), home to the brightest of all active galactic nuclei. The researchers suggest that they have discovered a whole new type of black hole activity at the centers of these six LINER galaxies. Infrared and Visible Light Images: ESA / Hubble, NASA, and S. Smartt (Queen & # 39; s University Belfast)

Observations of the Zwick transition mechanism reveal surprising transformations from sleep galaxies LINER to flaming quasars within months.

Galaxies are available in a wide variety of shapes, sizes and brightness, ranging from ordinary galaxies to luminous active galaxies. While an ordinary galaxy is visible mainly because of the light from its stars, an active galaxy shines brightest at its center or nucleus, where a supermassive black hole emits a constant burst of bright light as it persistently consumes gas and dust nearby.

  Flaming Quasars

The Concept of the Flaming Quasar Artist Credit: NASA / JPL-Caltech

Sitting somewhere in the spectrum between ordinary and active galaxies is another class known as low-ionic nuclear emission galaxies (EIN). Although LINERs are relatively common and represent approximately one-third of all nearby galaxies, astronomers are keen to discuss the main light-emitting source of LINERs. Some argue that poorly active galactic nuclei are responsible, while others argue that star-forming regions outside the galactic nucleus produce the most light.

A team of astronomers observe 6 suddenly and surprisingly six LINER galaxies, surprisingly and surprisingly transforming into raven quasars. to the brightest of all active galactic nuclei. The team reported their observations, which could help demystify the nature of both LINERs and quasars while answering some hot questions about galactic evolution, on The Astrophysical Journal on September 18, 2019. in their analysis, the researchers suggest they discovered a whole new type of black hole activity at the centers of these six galaxies LINER.

"For one of the six sites, we initially thought we were witnessing an ebb and flow event, which happens when a star goes too close to a supermassive black hole and splits," said Sarah Frederick, a student at the University of the Department. in Maryland Astronomy and lead author of scientific work. "But we found out later that this was a dead black hole, which had undergone a transition that astronomers call a 'changing species', leading to a vivid quasar. Observing six of these transitions, all in the relatively quiet LINER galaxies, suggests that we have identified a whole new class of active galactic nucleus. ”

All six of the surprising transitions were observed during the first nine months of the Zwick Transition Facility (ZTF), an automated sky survey project based at the Caltech Palomar Observatory near San Diego, California, which began observations in March 2018 UMD is a partner in the ZTF effort, aided by the Joint Space Science Institute (JSI), a partnership between UMD and NASA's Godard Space Center.

Changes in external transitions have been documented in other galaxies – most commonly in the class of active galaxies known as Seifert galaxies. By definition, all Seyfert galaxies have a bright, active galactic nucleus, but type 1 and type 2 Seyfert galaxies differ in the amount of light they emit at certain wavelengths. According to Frederick, many astronomers suspect that the difference is the result of the angle at which astronomers look at galaxies.

Seyfert Type 1 galaxies are thought to face the Earth with their heads down, giving an unobstructed view of their nuclei, while Type 2 Seyfert galaxies are tilted so that their nuclei are partially obscured by a ring in the shape of a donut made of thick, dusty gas clouds. Thus, the changing transitions between these two classes are a mystery to astronomers, since the orientation of a galaxy to Earth is not expected to change.

The new observations of Frederick and her colleagues may call into question these assumptions.

"We began to try to understand the changing transformations of appearance in Seyfert galaxies. But instead, we have discovered a whole new class of active galactic nucleus capable of transforming a galaxy of wisdom into a luminous quasar, "said Suvi Gesari, associate professor of astronomy at UMD, co-director of JSI and co-author of a research paper. "The theory suggests that the quasar may take thousands of years, but these observations suggest that it can happen very quickly. This tells us that the theory is wrong. We thought the main mystery was Seifert's transformation. But now we have a bigger problem to solve. "

Frederick and her colleagues want to understand how a previously quiet galaxy with a calm nucleus can suddenly switch to a bright beacon of galactic radiation. To learn more, they made follow-up observations on objects with the Discovery Channel telescope, operated by Lowell Observatory in partnership with UMD, Boston University, the University of Toledo and the University of Northern Arizona. These observations helped clarify aspects of the transitions, including how rapidly transforming galactic nuclei interact with their hosts.

"Our findings confirm that LINERs can actually host active supermassive black holes in their centers," says Frederick. "But these six transitions were so sudden and dramatic, it tells us that something completely different is happening in these galaxies. We want to know how so much gas and dust can suddenly fall into a black hole. As we captured these transitions in the act, it opens many opportunities to compare how the nuclei looked before and after the transformation. ”

Unlike most quasars, which illuminate the surrounding gas and dust clouds far beyond the galactic nucleus, the researchers found that only gas and dust closest to the nucleus were included. Frederick, Gesari, and their associates suspect that this activity is gradually spreading from the galactic nucleus – and may provide an opportunity to map the development of a newborn quasar.

"It is surprising that any galaxy can change its appearance on a human time scale. These changes happen much faster than we can explain with the current quasar theory, "says Frederick. "It will take some work to figure out what might disrupt the galaxy's buildup structure and cause these changes in such a short order. The forces that play must be very extreme and very dramatic. ”

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In addition to Frederick and Gesari, the co-authors of the UMD co-authored the research paper, including Associate Professor of Astronomy Bradley Cenko, formerly Neal

Research Paper,“ New Class Leaders with Variables ", Sarah Frederick, Suvi Gesari, Matthew Graham, Bradley Tsenko, Short Van Welzen, Daniel Stern, Mr. Erin Kara and Astronomy graduate student Charlotte Ward

Nadezhda Blagorodnova, Srinivas Kulkarni, Lin Kryngm, Lin Kryngm, Lin Kryngm , Tiara Hung, Erin Kara, David Shupe, Charlotte Ward, Eric Belm, Richard Decani, Dmitry Dou in, Ulrich Feynde, Matteo Jommy, Thomas Kupfer, Russ Laher, Frank Masks, Adam Miller, James Neal, Chow-Chong Ngeou, Maria Patterson, Michael Porter, Ben Ruslm, Jesper Solerman and Richard Walters901ical4ys Journal on September 18, 2019 . [19659022] (function (d, s, id) {
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