Messier 84 - the NGC Elliptical Galaxy

Description:

"The presence of a nuclear gas disk in M84 is especially interesting. If the gas exhibits Keplerian motion about the nucleus, then a straightfoward application of Newton’s laws to the dynamics of this gas disk would provide an estimate of the mass of the putative supermassive black hole (BH) in M84’s nucleus."

"We find an excess in the number of sources centered on M84 with a spatial distribution closely corresponding to the M84 stellar light. Given an absence of recent star formation, accreting binaries are the only candidates for the M84 X-ray sources. The most luminous sources, which we attribute to accreting black holes, exhibit X-ray colors typical of a blackbody spectrum. We also identify the sources whose X-ray colors match the expectations for constituents of the cosmic X-ray background."

“During the course of an investigation of the interaction of the radio galaxy M84 and its ambient cluster gas, we found excess X-ray emission aligned with the northern radio jet. The emission extends from the X-ray core of the host galaxy as a weak bridge and then brightens to a local peak coincident with the first detectable radio knot at ˜2.5" from the core. The second radio knot at 3.3" is brighter in both radio and X-rays. Although all the evidence suggests that Doppler favoritism augments the emission of the northern jet, it is unlikely that the excess X-ray emission is produced by inverse Compton emission. We find many similarities between the M84 X-ray jet and recent jet detections from Chandra data of low luminosity radio galaxies. For most of these current detections synchrotron emission is the favored explanation for the observed X-rays."

History of Observation:

"The number of compound nebulae that have been noticed in the foregoing three articles [on multiple nebulae] being so considerable, it will follow, that it they owe their origin to the breaking up of some former extensive nebulosities of the same nature with those which have been shewn to exist at present, we might expect that the number of separate nebulae should far exceed the former, and that moreover these scattered nebulae should be found not only in great abundance, but also in proximity or continuity of each other, according to the different extents and situations of the former diffusions of such nebulous matter. Now this is exactly what by observation, we find to be the state of the heavens."

Locating Messier 84: