Starship Asterisk*

Chandra images of 56 elliptical galaxies have revealed evidence for unsuspected turmoil. As this sample gallery of X-ray (blue & white) and optical (gray & white) images shows, the shapes of the massive clouds of hot gas that produce X-ray light in these galaxies differ markedly from the distribution of stars that produce the optical light.

Except for rare cases, most violent activity in isolated elliptical galaxies was thought to have stopped long ago. Elliptical galaxies contain very little cool gas and dust, and far fewer massive young stars which explode as supernovas. Thus it was expected that the hot interstellar gas would have settled into an equilibrium shape similar to, but rounder than that of the stars.

Surprisingly, this study of elliptical galaxies shows that the distribution of hot gas has no correlation with the optical shape. A powerful source of energy must be pushing the hot gas around and stirring it up every hundred million years or so.

Although supernovas are a possible energy source, a more probable cause has been identified. The scientists detected a correlation between the shape of the hot gas clouds and the power produced at radio wavelengths by high-energy electrons. This power source can be traced back to the supermassive black hole in the galaxies' central regions.

Repetitive explosive activity fueled by the infall of gas into the central supermassive black hole is known to occur in giant elliptical galaxies located in galaxy clusters. Scientists' analysis of the Chandra data indicates that the same phenomena are occurring in isolated elliptical galaxies as well.

mudman wrote:APOD 5/8/2009 seems to show a barred elliptical ringed galaxy. It is on the right side just above center.

JAlanScott wrote:a good closeup of this galaxy

harry wrote:This link is quite interesting about NGC1275
http://apod.nasa.gov/apod/ap080822.html

Fermi Discovery of Gamma-Ray Emission from NGC 1275

Authors: The Fermi/LAT Collaboration: A. A. Abdo, et al, H.D. Aller, M.F. Aller, K.I. Kellermann, Y.Y. Kovalev, Y.A. Kovalev, M. L. Lister, A. B. Pushkarev

These filaments are caused by a single point source that eliminates the probability of disc influence. This maybe evidence for the ability of blackholes to release matter at a huge rate. Just a thought.

Abstract: We report the discovery of high-energy (E>100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the Fermi Gamma ray Space Telescope. The positional center of the gamma-ray source is only ~3' away from the NGC 1275 nucleus, well within the 95% LAT error circle of ~5'.The spatial distribution of gamma-ray photons is consistent with a point source. The average flux and power-law photon index measured with the LAT from 2008 August 4 to 2008 December 5 are F_gamma = (2.10+-0.23)x 10^{-7} ph (>100 MeV) cm^{-2} s^{-1} and Gamma = 2.17+-0.05, respectively. The measurements are statistically consistent with constant flux during the four-month LAT observing period.Previous EGRET observations gave an upper limit of F_gamma < 3.72x 10 ^{-8} ph (>100 MeV) cm^{-2} s^{-1} to the gamma-ray flux from NGC 1275. This indicates that the source is variable on timescales of years to decades, and therefore restricts the fraction of emission that can be produced in extended regions of the galaxy cluster. Contemporaneous and historical radio observations are also reported. The broadband spectrum of NGC 1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.