6 research outputs found
A Possible Detection of M31* with Chandra
Two independent sets of Chandra and HST images of the nuclear region of M31
allow registration of X-ray and optical images to 0.1''. This registration
shows that none of the bright (10^{37} erg/s) X-ray sources near the nucleus is
coincident with the central super-massive black hole, M31*. A 50ks Chandra HRC
image shows 2.5 sigma evidence for a faint (3 x 10^{35} erg/s), apparently
resolved source which is consistent with the position of the M31*. The Bondi
radius of M31* is 0.9'', making it one of the few super-massive black holes
with a resolvable accretion flow. This large radius and the previous detections
of diffuse, X-ray emitting gas in the nuclear region make M31* one of the most
secure cases for a radiatively inefficient accretion flow and place some of the
most severe constraints on the radiative processes in such a flow.Comment: 14 pages, 5 figures, submitted to Ap
The X-ray Polarization Probe mission concept
The X-ray Polarization Probe (XPP) is a second generation X-ray polarimeter
following up on the Imaging X-ray Polarimetry Explorer (IXPE). The XPP will
offer true broadband polarimetery over the wide 0.2-60 keV bandpass in addition
to imaging polarimetry from 2-8 keV. The extended energy bandpass and
improvements in sensitivity will enable the simultaneous measurement of the
polarization of several emission components. These measurements will give
qualitatively new information about how compact objects work, and will probe
fundamental physics, i.e. strong-field quantum electrodynamics and strong
gravity.Comment: submitted to Astrophysics Decadal Survey as a State of the Profession
white pape
Science Highlight: Chandra Observations of Ultra-luminous Sources in Starbursts -- Mid-Mass Black Holes or Microquasars?
The Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA), a unified worldwide effort and the sole proposed implementation of the "Advanced Cherenkov Telescope Array" recommended by the Astro2010 survey, is a ground-based instrument for studies of very-high-energy gamma rays from 20 GeV to 300 TeV. This white paper summarizes the CTA project and its science goals