Related papers: X-ray Scattering Halos from the Galactic Center: I…
The supermassive black hole at the Galactic center, Sagittarius A*, has experienced periods of higher activity in the past. The reflection of these past outbursts is observed in the molecular material surrounding the black hole but…
In a recent study (Maoz and Grindlay 1995) we have found that a number of previously recognized anomalies in the diffuse x-ray background at soft energies (\sim 0.5-2 keV) can be understood if about 20-30% of the diffuse flux arises from a…
We present a catalog of 34 diffuse features identified in X-ray images of the Galactic center taken with the Chandra X-ray Observatory. Several of the features have been discussed in the literature previously, including 7 that are…
Using Chandra observations we have measured the energy-resolved dust-scattered X-ray halo around the low-mass X-ray binary GX5-1, which shows signs of both singly- and multiply-scattered X-rays. We compared the observed X-ray halo at…
A new study of the diffuse Galactic gamma-ray continuum radiation is presented, using a cosmic-ray propagation model which includes nucleons, antiprotons, electrons, positrons, and synchrotron radiation. Our treatment of the inverse Compton…
The Galactic Center provides a unique opportunity to observe a galactic core, objects in close proximity to a supermassive black hole (SMBH), and star formation channels that exhibit imprints of this peculiar environment. This habitat…
Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), we have carried out a deep hard X-ray observation of the Galactic plane region at (l,b) ~ (28.5, 0.0), where no discrete X-ray source had been reported previously.…
The 10 by 10 degrees region around dynamic center of our Galaxy is known to host a large number of bright X-ray sources, most of which are low mass binary systems. While high luminosity Z-sources are especially bright in the standard X-ray…
Daily X-ray flaring represents an enigmatic phenomenon of Sgr A$^{\star}$ --- the supermassive black hole at the center of our Galaxy. We report initial results from a systematic X-ray study of this phenomenon, based on extensive {\it…
We analyze deep near-IR adaptive optics imaging as well as new proper motion data of the nuclear star cluster of the Milky Way. The surface density distribution of faint stars peaks within 0.2" of the black hole candidate SgrA*. The radial…
For a decade now, evidence has accumulated that giant molecular clouds located within the central molecular zone of our Galaxy reflect X-rays coming from past outbursts of the supermassive black hole Sgr A*. However, the number of…
GALEX has detected ultraviolet halos extending as far as 5$^{\circ}$ around four bright stars (Murthy et al. (2011)). These halos are produced by scattering of starlight by dust grains in thin foreground clouds that are not physically…
We report new simultaneous near-infrared/sub-millimeter/X-ray observations of the SgrA* counterpart associated with the massive 3-4x10**6 solar mass black hole at the Galactic Center. The main aim is to investigate the physical processes…
Continuum low-frequency radio observations of the Galactic Center reveal the presence of two prominent radio sources, Sgr A East and its surrounding Halo, containing non-thermal particle distributions with power-law indices around 2.5-3.3…
The surface brightness produced by synchrotron radiation in Clusters of Galaxies with a radio-halo sets a degenerate constraint on the magnetic field strength, the relativistic electron density and their spatial distributions. Using the…
The ~1 Ms Chandra Deep Field North observation is used to study the extended X-ray sources in the region surrounding the Hubble Deep Field North (HDF-N), yielding the most sensitive probe of extended X-ray emission at cosmological distances…
I review radiatively inefficient accretion flow models for the 2.6 million solar mass black hole (BH) in the Galactic Center. I argue for a 'concordance model' of Sgr A*: both theory and observations suggest that hot ambient gas around the…
We observed several nearby face-on spiral galaxies with the ROSAT PSPC to study their 0.1-2.0 keV diffuse emission. After the exclusion of resolved discrete sources, there is unresolved X-ray emission in all the galaxies observed. Since…
Here we review our current knowledge on diffuse gamma-rays from galactic halos. Estimates of the relative contribution of the various emission processes at low and high latitudes are compared to the data over 6 decades in energy. The…
The supermassive black hole at the centre of the Galaxy flares at least daily in the infrared (IR) and X-ray bands, yet the process driving these flares is still unknown. So far detailed analysis has only been performed on a few bright…