Hubble observes tiny galaxy with big heart

Hubble observes tiny galaxy with big heart
Nestled within this field of bright foreground stars lies ESO 495-21, a tiny galaxy with a big heart. ESO 495-21 is just 3000 light-years across, a fraction of the size of the Milky Way, but that is not stopping the galaxy from furiously forming huge numbers of stars. Credit: ESA/Hubble, NASA

Nestled within this field of bright foreground stars lies ESO 495-21, a tiny galaxy with a big heart. ESO 495-21 may be just 3000 light-years across, but that is not stopping the galaxy from furiously forming huge numbers of stars. It may also host a supermassive black hole; this is unusual for a galaxy of its size, and may provide intriguing hints as to how galaxies form and evolve.

Located about 30 million light-years away in the constellation of Pyxis (The Compass), ESO 495-21 is a dwarf starburst galaxy—this means that it is small in size, but ablaze with rapid bursts of star formation. Starburst galaxies form stars at exceptionally , creating stellar newborns of up to 1000 times faster than the Milky Way.

Hubble has studied the bursts of activity within ESO 495-21 several times. Notably, the has explored the galaxy's multiple super star clusters, very dense regions only a few million years old and packed with . These spectacular areas can have a huge impact on their . Studying them allows astronomers to investigate the earliest stages of their evolution, in a bid to understand how massive stars form and change throughout the Universe.

As well as hosting the cosmic fireworks that are super star clusters, ESO 495-21 also may harbour a at its core. Astronomers know that almost every large galaxy hosts such an object at its centre, and, in general, the bigger the galaxy, the more massive the black hole. Our home galaxy, the Milky Way, houses a supermassive black hole, Sagittarius A*, which is over four million times as massive as the Sun. ESO 495-21, also known as Henize 2-10) is a dwarf galaxy, only three percent the size of the Milky Way, and yet there are indications that the black hole at its core is over a million times as massive as the Sun—an extremely unusual scenario.

This black hole may offer clues as to how and galaxies evolved in the early Universe. The origin of the central supermassive black holes in galaxies is still a matter of debate—do the galaxies form first and then crush material at their centres into black holes, or do pre-existing black holes gather galaxies around them? Do they evolve together—or could the answer be something else entirely?

With its , indistinct shape, and rapid starburst activity, astronomers think ESO 495-21 may be an analogue for some of the first galaxies to have formed in the cosmos. Finding a black hole at the galaxy's heart is therefore a strong indication that black holes may have formed first, with galaxies later developing and evolving around them.

The data comprising this image were gathered by two of the instruments aboard the NASA/ESA Hubble Space Telescope: the Advanced Camera for Surveys and already decommissioned Wide Field Planetary Camera 2/.


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Citation: Hubble observes tiny galaxy with big heart (2019, June 13) retrieved 18 July 2019 from https://phys.org/news/2019-06-hubble-tiny-galaxy-big-heart.html
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Jun 13, 2019
If I am reading this correctly, the dwarf galaxy has 1/30 our total mass yet 1/4 our black hole mass. But then Andromeda has about the same total mass as us but their black hole is 60 times larger. Hmmm, what is the normal length of a piece of string?
The new space telescope going up next year will be explaining so much it will become extremely difficult even staying current with the highlights. Too cool.

Jun 13, 2019
@etherair
Hmmm, what is the normal length of a piece of string?

Depends on how long it is.

Jun 13, 2019
There are some very complicated issues of galaxy formation. Unfortunately, here is the same problem as with the stars. The origin of galaxies remains unclear, in spite of huge activity in the field. What the "formation" means? It means that we have the material that is assembling into galaxies.
https://www.acade...ome_From

Jun 13, 2019
I like how the end of the video creates an optical illusion that seems to stay in motion after the video stops.

Jun 13, 2019
the constant improvement of observation technology & confirming analysis?
is a big problem for people who expect natural phenomena to obey rigid rules & regulations.

this Universe,variations in galaxies as certainly as proto-planetary disks of unpredictable space junk.
malleable biological organisms as well as uncertain outcomes of sexual reproduction.

all have stochastic processes in common.

this all is propelled by the irrational reality of Pi & Phi.

all you can accurately predict is that some unpredictable event is going to surprise you.

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