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M31: Black Hole Bonanza Turns up in Galaxy Next Door

  • Twenty-six black hole candidates have been identified in Andromeda, aka M31, adding to 9 previously found.

  • This is the largest number of possible black holes to date ever found in a galaxy outside of our own Milky Way.

  • These are stellar-mass black holes, which are formed by the collapse of a giant star and have masses between five and 10 times the Sun's.

  • Researchers used over 150 separate Chandra observations spread over 13 years to obtain these results.

Data from NASA's Chandra X-ray Observatory have been used to discover 26 black hole candidates in the Milky Way's galactic neighbor, Andromeda, as described in our latest press release. This is the largest number of possible black holes found in a galaxy outside of our own.

A team of researchers, led by Robin Barnard of the Harvard-Smithsonian Center for Astrophysics, used 152 observations of Chandra spanning over 13 years to find the 26 new black hole candidates. Nine were known from earlier work. These black holes belong to the stellar-mass black hole category, which means they were created when a massive star collapsed and are about 5 to 10 times the mass of the Sun.

This wide-field view of Andromeda contains optical data from the Burrell Schmidt telescope of the Warner and Swansey Observatory on Kitt Peak in Arizona. Additional detail of the core and dust in the spiral arms comes from an image taken by astrophotographer Vicent Peris using data from two of his personal telescopes. In this combined optical image, red, green, and blue show different bands from the visible light portion of the electromagnetic spectrum.

The inset contains X-ray data from multiple Chandra observations of the central region of Andromeda. This Chandra image shows 28 of the 35 black hole candidates in this view, visible by mousing over the image. The other seven candidates can be seen in this Chandra image with a larger field of view.

X-ray close-up
Chandra X-ray close-up of M31's core, with sources circled.

Seven of the 35 black hole candidates are within only 1,000 light years of the Andromeda Galaxy's center (mouse over the image for the dotted circle enclosing these sources). This is more than the number of black hole candidates with similar properties located near the center of our own Galaxy. This, however, does not take astronomers by surprise, since the bulge of stars in the middle of Andromeda is bigger, allowing more black holes to form.

Eight of the nine black hole candidates that were previously identified are associated with globular clusters, the ancient concentrations of stars distributed in a spherical pattern about the center of the galaxy. This also differentiates Andromeda from the Milky Way as astronomers have yet to find a similar black hole in one of the Milky Way's globular clusters.

Andromeda, also known as Messier 31 (M31), is a spiral galaxy located about 2.5 million light years away. It is thought that the Milky Way and Andromeda will collide several billion years from now. The black holes located in both galaxies will then reside in the large, elliptical galaxy that results from this merger.

These results are available online and will be published in the June 20th issue of The Astrophysical Journal. Many of the Andromeda observations were made within Chandra's Guaranteed Time Observer program.


Fast Facts for M31:
Credit  X-ray (NASA/CXC/SAO/R.Barnard, Z.Lee et al.), Optical (NOAO/AURA/NSF/REU Prog./B.Schoening, V.Harvey; Descubre Fndn./CAHA/OAUV/DSA/V.Peris)
Release Date  June 12, 2013
Scale  Optical image is 2 degrees across (about 100,000 light years); inset image is 14 arcmin across (about 12,000 light years)
Category  Normal Galaxies & Starburst Galaxies, Black Holes
Coordinates (J2000)  RA 00h 40m 27s | Dec 40° 40´ 12"
Constellation  Andromeda
Observation Date  152 pointings between 1999 and 2012
Observation Time  55 hours 30 min (2 days 7 hours 30 min)
Instrument  ACIS
Also Known As Andromeda
References Barnard, R. et al, 2013, ApJ 770, 148; arXiv:1304.7780
Color Code  X-ray (Purple); Optical (Red, Green, Blue)
Distance Estimate  About 2.5 million light years
distance arrow
Visitor Comments (22)

I agree with Ron's post on 6-13-13 at 8 58 am. Since energy cannot be created or destroyed, I believe the big bang is the result of a expired universe or maybe somehow black holes are involved in creating a big bang.

Posted by Mark on Tuesday, 06.6.17 @ 10:39am

A black hole in any of the pictures shown of any galaxy looks white... Strange misnomer.

Posted by Yathiender Sridharan on Friday, 11.27.15 @ 06:39am

The image of Andromeda galaxy is super. I appreciate all the information allied with Andromeda. I was surprised to learn that it has 35 black holes candidates which were caused by the collapse of a giant star. The collapse of one massive star may create many black holes is what I learned afresh. well, how many black hole candidates are in our Milky Way galaxy?

Posted by Dravida shaan on Saturday, 08.22.15 @ 11:10am

This is an amazing experience, I only see it in my imagination.

Posted by DUNCAN WOLF on Wednesday, 10.22.14 @ 12:53pm

This information is really great. But my question has nothing to do with the above. If someone happen to read my comment and could answer my question, please don t hesitate to write an e-mail to me. Anyway, my question is Are there anti-matter swirling in black holes?

Posted by Ricki Warmheart on Monday, 07.21.14 @ 12:39pm

It's always amazing and incredible. Thanks a lot. I could never imagine that our neighbor will have a such number of black holes near its center. I am really fascinated with that, but I need more, it is like a part is missing to explain more this phenomenon.

Posted by NASAFan on Tuesday, 07.15.14 @ 08:18am

More info please. I had to write a 3 paragraph essay about this but I did not have enough info. Thanks so much.

Posted by hinksdt heart on Tuesday, 04.1.14 @ 22:19pm

This includes grate information, but I need more.

Posted by Manage on Friday, 12.27.13 @ 14:09pm

It urges you to go out there and observe them from the nearest possible distance these pictures. I hope we develop the technology, in my life time, to get to all these stars we see or may be get out of our solar system in one life time or may be less, it will be fascinating.

Posted by Lovish on Thursday, 11.14.13 @ 16:15pm

I see where scientists say "galaxies with black holes", does that mean that there are some galaxies without black holes? if there are, then what the heck is keeping all those stars spiraling together? I know its a mystery how the black holes are affecting the stars at the edges of galaxies, but just wondering about those without black holes. Fascinating universe. AWESOME

Posted by chad on Monday, 11.4.13 @ 02:10am

Beautiful photographs and really great observation.

Posted by kalpesh on Sunday, 07.28.13 @ 00:41am

Black hole is important projection for future.

Posted by elsanosse on Saturday, 07.13.13 @ 15:14pm

Kolya's theory of black holes forming one big black hole is fascinating. What do you suppose is the time scale of the first BANG to the second BANG? Are we in a never ending cycle?

Posted by John F Gans on Monday, 06.24.13 @ 11:20am

If a supernova explodes, does the amount of matter emitted from the explosion equal the original mass, or is there something missing? Unless we physically see one happening and know what was there before, is it possible that all we are seeing is the sudden emission from super massive black hole?

Posted by Andy on Monday, 06.17.13 @ 06:24am

Fantastic imagery. Thank you!

Posted by Phil Huff on Saturday, 06.15.13 @ 10:11am

Black holes are very interesting to read and see in NASA's Chandra X-ray Observatory. 26 of black hole candidate is not so few.

Posted by Heljo Valter on Friday, 06.14.13 @ 12:28pm

Wow, and where do we keep going?

Posted by rick moll on Friday, 06.14.13 @ 04:11am

I think all of the black hole is time to unite and map of the galaxy. It will give scientists time to monitor their dynamics and location.

Posted by Alex Kulay on Thursday, 06.13.13 @ 23:50pm

I appreciate this and other articles from NASA.
I wish we could travel faster than light, but I believe Dr. Einstein ruled that out many years ago. Always wonder what these distant objects look like now.

Posted by Steve Webb on Thursday, 06.13.13 @ 12:23pm

Want to see more.

Posted by gray kolya on Thursday, 06.13.13 @ 09:00am

It appears to me, that, eventually all the black holes will join up
in every galaxy, with gravity being so powerful, all the galaxies
will be attracted to each other, and all the black holes will eventually
join together to form one black hole, and then BANG a new Universe.

Posted by RON on Thursday, 06.13.13 @ 08:58am

Very important information &great photos

Posted by Rajika RUwini on Thursday, 06.13.13 @ 02:49am

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