Distribution And Nature Of The Accretion-powered Binaries In The Galactic Center Region From The Chandra BLS
Abstract
We have completed the analysis of the Chandra Bulge Latitude Survey (BLS), a close-tiled mosaic of 36 ACIS-I fields obtained with Chandra in cycles 7 - 9 and covering (l, b) +/-0.3, +/-1.4deg. With 15ksec exposures per field, some 2500 sources are detected, with luminosities Lx(0.3-8keV) > 10^32 erg/s. This survey maps the latitude distribution of the galactic center region (GCR) sources for comparison with the longitude distribution of the Wang et al (2002) survey. The BLS extends below the plane to (just) include the "Limiting Window" field (b = -1.3deg, the closest low extinction window to SgrA* with Av 4) we originally observed in a 100ksec pointing and which was recently observed in a much deeper pointing by Revnivtsev et al to study the Galactic Ridge. From our optical (VRI; CTIO-4m/Mosaic) and nIR (JHK; CTIO-4m/ISPI) images, we identify foreground sources and constrain the Bulge sources to not be wind-fed high mass systems. By selecting on sources detected in the Hard (>2keV) but not in the Soft (<2keV) bands, we can reject foreground sources and measure the latitude and projected radial distributions of the hard sources in the GCR that are likely dominated by accreting white dwarfs (CVs) but also include quiescent low mass X-ray binaries (qLMXBs). And from comparison with the Wang survey, the combined radial distribution of Lx 10^32-33 erg/s hard sources in the GCR, which are dominated by accreting compact objects in binaries, is derived for comparison with models of the Bulge and its formation history.
- Publication:
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American Astronomical Society Meeting Abstracts #218
- Pub Date:
- May 2011
- Bibcode:
- 2011AAS...21812206G