Is M85 missing a black hole?

Oct 17, 2011 By Jon Voisey, Universe Today
Galaxy M85. Image credit: NOAO/AURA/NSF

The conventional wisdom of galaxies is that they should have a central massive black hole (CMBH). The presence of such objects has been confirmed in our own galaxy as well as numerous other galaxies, including the Andromeda galaxy (M31) and even some dwarf galaxies. The mass of these objects, several million times the mass of the Sun, has been found to be related to many properties of galaxies as a whole, indicating that their presence may be critical in the formation and evolution of galaxies as a whole. As such, finding a massive galaxy without a central black hole would be quite surprising. Yet a recent study by astronomers from the University of Michigan Ann Arbor seems to have found an exception: The well known M85.

To determine the mass of the CMBH, the team used the spectrograph on board the to examine the pull the central object had on stars in the nearby vicinity. The higher this mass is, the more quickly the stars should orbit. This is detected as a shift in the color of the light, blue as the stars move towards us, red as they move away. The amount the light is shifted is dependent on just how fast they move.

This technique has been used previously in other galaxies, including another large elliptical of similar brightness in the Messier catalog, M84. This galaxy had its CMBH probed by Hubble in 1997 and was determined to have a mass of 300 million .

Doppler shift of gas and dust caused by M84's supermassive black hole. Image Credit: Gary Bower, Richard Green (NOAO), the STIS Instrument Definition Team, and NASA

When this method was applied to M85 the team did not discover a shift that would be indicative of a black hole with a mass expected for a galaxy of such size. Using another, indirect method of determining the CMBH mass by looking at the the amount of overall light from the galaxy, which is generally correlated with black hole mass, would indicate that M85 should contain a black hole of 300 million to 2 billion solar masses. Yet this study indicates that, if M85 contains a central black hole at all, the upper limit for the black hole would be around 65 million solar masses.

This study is not the first to report a non-detection for the galaxy, a 2009 study led by Alessandro Capetti from Osservatorio Astronoimco di Torino in Italy, searched M85 for signs of radio emission from the black hole region. Their study was unable to detect any significant radio waves from the core which, if M85 had a significant black hole, should be present, even with a small amount of gas feeding into the core.

Overall, these studies demonstrate a significant shortcoming in secondary methods of black hole mass estimation. Such indirect methods have been previously used with confidence and have even been the basis for studies drawing the connection between galaxy evolution and black hole mass. If cases like M85 are more common that previously thought, it may prompt astronomers to rethink just how connected black holes and a galaxies properties really are.

Explore further: Witnessing the early growth of a giant

add to favorites email to friend print save as pdf

Related Stories

Astronomers calculate mass of largest black hole yet

Jan 14, 2011

(PhysOrg.com) -- Weighing 6.6 billion solar masses, the black hole at the center of galaxy M87 is the most massive black hole for which a precise mass has been measured. Using the Frederick C. Gillett Gemini ...

Measuring galaxy black hole masses

May 27, 2011

(PhysOrg.com) -- Black holes, one of the most amazing and bizarre predictions of Einstein's theory of gravity, are irresistible sinks for matter and energy. They are so dense that not even light can escape ...

Image: A supermassive black hole

Jan 24, 2011

(PhysOrg.com) -- In a single exposure, astronomers were able to confirm the existence of a supermassive black hole in the center of galaxy M84.

Cosmic weight watching reveals black hole-galaxy history

Sep 30, 2011

(PhysOrg.com) -- Using state-of-the-art technology and sophisticated data analysis tools, a team of astronomers from the Max Planck Institute for Astronomy has developed a new and powerful technique to directly ...

Surprise: Dwarf galaxy harbors supermassive black hole

Jan 09, 2011

(PhysOrg.com) -- The surprising discovery of a supermassive black hole in a small nearby galaxy has given astronomers a tantalizing look at how black holes and galaxies may have grown in the early history ...

Chandra finds nearest pair of supermassive black holes

Aug 31, 2011

(PhysOrg.com) -- Astronomers have used NASA's Chandra X-ray Observatory to discover the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way. At a distance of 160 million light ...

Recommended for you

Witnessing the early growth of a giant

13 hours ago

Astronomers have uncovered for the first time the earliest stages of a massive galaxy forming in the young Universe. The discovery was made possible through combining observations from the NASA/ESA Hubble ...

Evidence for supernovas near Earth

20 hours ago

Once every 50 years, more or less, a massive star explodes somewhere in the Milky Way. The resulting blast is terrifyingly powerful, pumping out more energy in a split second than the sun emits in a million ...

What lit up the universe?

Aug 27, 2014

New research from UCL shows we will soon uncover the origin of the ultraviolet light that bathes the cosmos, helping scientists understand how galaxies were built.

Eta Carinae: Our Neighboring Superstars

Aug 26, 2014

(Phys.org) —The Eta Carinae star system does not lack for superlatives. Not only does it contain one of the biggest and brightest stars in our galaxy, weighing at least 90 times the mass of the Sun, it ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
1.3 / 5 (12) Oct 17, 2011
these studies demonstrate a significant shortcoming in secondary methods of black hole mass estimation. Such indirect methods have been previously used with confidence and have even been the basis for studies drawing the connection between galaxy evolution and black hole mass. If cases like M85 are common, it may prompt astronomers to rethink just how connected black holes and a galaxies properties really are.


Astronomers have a lot of rethinking to do, beginning with the nearby star that is the model for others:

Strange xenon, extinct super-heavy elements and the solar neutrino puzzle, Science 195, 208-209 (1977)

www.omatumr.com/a...enon.pdf

Isotopes of tellurium, xenon, and krypton in Allende meteorite retain record of nucleosynthesis, Nature 277, 615-620 (1979)

http://www.nature...5a0.html

"Is the Sun a pulsar?" Nature 270, 159-160 (1977)

www.nature.com/na...9a0.html

O. Manuel


Tuxford
1 / 5 (3) Oct 17, 2011
Likely more homogeneous-appearing galaxies without significant structure lack a significant core 'grey'-hole star which periodically ejects new matter in superwaves, seeding the galaxy from the inside-out. Instead, the primary mechanism forming these types of galaxies would be condensation of pre-existing gas clouds, as conventionally believed for all galaxies.
rawa1
5 / 5 (2) Oct 17, 2011
Some black holes could get ejected from parent galaxy with gravitational slingshot mechanism. http://prints.iia...galaxies
Pyle
not rated yet Oct 17, 2011
Zephyr, what is even better is that SMBH's have a very large local effect, but really don't play too much into the overall structure of galaxies later in their development. Per current theory, dark matter is the glue, not the CBH.

And better than that, while the ejected BH might grab a few stars, they could be very difficult to detect out in the inter galactic medium, owing to the decrease in food consumption and resulting reduction in radiation generated.

(No original thoughts here, all is shared from original article discussion on UT.)

All this is just ideas. I claim no explanation for M85.
hush1
1 / 5 (2) Oct 19, 2011
I'm a 'no black hole' fanboy.
I'm against the math describing black holes. In other words a closet Crothers - à la Stephen J. Crothers.

I like it when my team scores a physical point.
It's no fluke.