Supermassive black holes manage star formation in large galaxies

Astronomers find a close correlation between the mass of a galaxy's central black hole and its star formation history.


Youthful galaxies blast with splendid new stars framing at a quick rate, yet star development, in the long run, close down as a cosmic system advances. A recent study by the UC Santa Cruz shows that the mass of the black hole in the center of the galaxy determines how soon this “quenching” of star formation occurs.

Each enormous world has a focal supermassive black hole, more than a million times more gigantic than the sun, uncovering its quality through its gravitational impacts on the universe’s stars and in some cases driving the lively radiation from a dynamic galactic core (AGN). The vitality filling a world from a dynamic galactic core is thought to kill star arrangement by warming and scattering the gas that would some way or another consolidate into stars as it cooled.

This thought has been around for quite a long time, and astrophysicists have discovered that recreations of world advancement must join criticism from the black hole so as to duplicate the watched properties of systems. Be that as it may, observational confirmation of an association between supermassive black holes and star development has been missing, as of not long ago.

Jean Brodie, professor of astronomy and astrophysics at UC Santa Cruz said, “We’ve been dialing in the feedback to make the simulations work out, without really knowing how it happens. This is the first direct observational evidence where we can see the effect of the black hole on the star formation history of the galaxy.”

Scientists mainly focused on massive galaxies for which the mass of the central black hole had been measured in previous studies by analyzing the motions of stars near the center of the galaxy. To determine the star formation histories of the galaxies, Martín-Navarro analyzed detailed spectra of their light obtained by the Hobby-Eberly Telescope Massive Galaxy Survey.

Spectroscopy empowers cosmologists to isolated and measures the distinctive wavelengths of light from an object. Martín-Navarro utilized computational methods to break down the range of every cosmic system and recuperate its star development history by finding the best mix of stellar populaces to fit the spectroscopic information.

Comparing the star formation histories of galaxies with black holes of different masses, they found striking differences. These differences only correlated with black hole mass and not with galactic morphology, size, or other properties.

Martín-Navarro said, “For galaxies with the same mass of stars but different black hole mass in the center, those galaxies with bigger black holes were quenched earlier and faster than those with smaller black holes. So star formation lasted longer in those galaxies with smaller central black holes.”

“We used black hole mass as a proxy for the energy put into the galaxy by the AGN, because accretion onto more massive black holes leads to more energetic feedback from active galactic nuclei, which would quench star formation faster.”

Romanowsky said, “There are different ways a black hole can put energy out into the galaxy, and theorists have all kinds of ideas about how quenching happens, but there’s more work to be done to fit these new observations into the models.”

The study is published January 1, 2018, in Nature.


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