Raucous Active Galaxy Destroys Own Environment


One of the best things about modern astronomy is that we can “see” with our instruments a whole lot that our eyes could never see. This very cool new image from the Chandra X-Ray Observatory, along with a radio image from the Very Large Array, shows the galaxy-altering power of the active supermassive black hole in the center of M87.

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M87 is a massive elliptical galaxy at the center of the nearby Virgo Cluster. The Virgo Cluster of galaxies is like the nearby metropolis to which our galaxy resides in the distant suburbs.

Known for a long time to be a powerful radio source, it was found to have a supermassive black hole that was feeding on surrounding gas. Although a few billion times the mass of the sun — which is HUGE to us — it is just a tiny fraction of the mass of the galaxy. And yet, its actions influence the entire galaxy, as well as the cluster around it.

Whereas the radio emission comes from jets of material that are flung away from the black hole’s vicinity at speeds nearing that of light, the x-ray emission comes from the hot soup of particles that pervade the galactic cluster. These interact as the radio jets appear to blow “bubbles” or cavities into the x-ray gas.

Zooming in on a monster with the VLA and VLBA, two of my favorite telescopes.

Enter the newest studies led by Norbert Werner and Evan Million. They stared at M87 with Chandra for almost 160 hours and combined that with data from XMM-Newton and high-resolution optical images and spectra. Putting the pieces together provided observational evidence of the physical link between the actions of the supermassive black hole and what is going on the in the rest of the galaxy.

Such active black holes, called AGNs or active galactic nuclei, were thought to be oddities as astronomers began to piece together their story in the 1960s. Now, however, astronomers think that most galaxies go through an AGN phase at some point during their development and that the consequences of this phase profoundly affect the galaxies’ future development.

In this case, the incredible AGN at the center of M87 is stirring-up and heating the gas in the galaxy so much that it cannot collapse and form new stars. Without the AGN to do this, this massive galaxy at the center of a large cluster would have gas raining down on it from all directions, likely sparking an incredible starburst. Yet, the AGN keeps the system regulated. The press release likens this to similar processes in the Eyjafjallajokull volcano eruption earlier this year.

We live in a seriously powerful and strange universe. Though the picture of the evolution of galaxies is fuzzy at best, astronomers will keep pointing incredible telescopes at them to gain a better understanding.

Image Credits: Top – X-ray (NASA/CXC/KIPAC/N. Werner, E. Million et al), Radio (NRAO/AUI/NSF/F. Owen); Middle – NRAO/AUI (F. Owen, J. Biretta, J. Eilek, & N. Kassim); Bottom – same as X-Ray on top.

Preprints part 1 and part 2 are available on arxiv.org.

Thanks to Jeff Carlin with helping my analogies, even though I bugged him while he was trying to finish his thesis!

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