A remote galaxy has actually been captured in the act of closing down.

The galaxy, called CQ 4479, is still forming lots of new stars. However it also has an actively feeding supermassive black hole at its center that will bring star development to a halt within a couple of hundred million years, astronomers reported January 11 at the virtual meeting of the American Astronomical Society. Studying this galaxy and others like it will assist astronomers find out precisely how such shutdowns occur.

” How galaxies precisely die is an open question,” says astrophysicist Allison Kirkpatrick of the University of Kansas in Lawrence. “This might offer us a great deal of insight into that process.”

Astronomers think galaxies usually begin making new stars with a passion. The stars form from pockets of cold gas that contract under their own gravity and fire up atomic combination in their centers. At some point, something disrupts the cold star-forming fuel and sends it toward the supermassive black hole at the galaxy’s core. That great void gobbles the gas, warming it white-hot. An actively feeding great void can be seen from billions of light-years away and is called a quasar. Radiation from the hot gas pumps extra energy into the rest of the galaxy, blowing away or heating up the staying gas up until the star-forming factory closes for great ( SN: 3/5/14).

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That image fits with the types of galaxies astronomers typically see in the universe: “blue and brand-new” star formers, and “red and dead” dormant galaxies. While analyzing data from large surveys of the sky, Kirkpatrick and colleagues discovered another type. The team discovered about 2 lots galaxies that emit energetic X-rays characteristic of an actively gobbling great void, however also shine in low-energy infrared light, revealing that there is still cold gas someplace in the galaxies. Kirkpatrick and colleagues called these galaxies “cold quasars” in a paper in the Sept. 1 Astrophysical Journal

” When you see a black hole actively accreting material, you anticipate that star development has actually already shut down,” states coauthor and astrophysicist Kevin Cooke, also of the University of Kansas, who presented the research study at the conference. “However cold quasars are in a weird time when the black hole in the center has actually just started to feed.”

To investigate individual cold quasars in more detail, Kirkpatrick and Cooke used SOFIA, an airplane equipped with a telescope that can see in a variety of infrared wavelengths that the original cold quasar observations didn’t cover.

The observations showed that CQ 4479 has about 20 billion times the mass of the sun in stars, and it’s adding about 95 suns per year. In terms of percentage of their total mass, the stars and the black hole are growing at the very same rate, Kirkpatrick states.

cold quasar CQ 4479
The cold quasar CQ 4479, the blue fuzzy dot at the center of this image, appeared in images taken by the Sloan Digital Sky Study. The red dot nearby may be another galaxy engaging with CQ 4479, or it might be unrelated. K.C. Cooke et al/ 2020, Sloan Digital Sky Survey

That sort of “lockstep development” runs counter to theories of how galaxies wax and wane. “You ought to have all your stars finish growing initially, and after that your black hole grows,” Kirkpatrick says. “This [galaxy] shows there’s a period that they actually do grow together.”

Cooke and coworkers estimated that in half a billion years, the galaxy will host 100 billion solar masses of stars, but its black hole will be passive and peaceful. All the cold star-forming gas will have heated up or blown away.

The observations of CQ 4479 support the broad concepts of how galaxies die, says astronomer Alexandra Pope of the University of Massachusetts Amherst, who was not involved in the new work. Given that galaxies ultimately change off their star development, it makes sense that there ought to be a period of shift.


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