ChaMPlane, Bulge Windows and Bulge Latitude Surveys
A major survey using Chandra archival data as well as optical imaging
and spectroscopy for source identifications has been underway since
2001. The Chandra Multi-wavelength Plane (ChaMPlane) Survey uses
archival ACIS-I and -S images from Chandra pointings within |b| < 11
deg and exposure times T > 10 ksec, in order to make an unbiased
survey for the low-luminosity point source population of X-ray sources
in the Galaxy. Only images without bright point sources, clusters or
diffuse emission for their original targets, are selected. The
primary objective is to measure or constrain the various populations
of accretion-powered sources: accreting white dwarfs (cataclysmic
variables), neutron stars and black holes (quiescent low-mass X-ray
binaries) and the most numerous high-mass X-ray binaries containing Be
stars as mass donors. The principal secondary objective is to study
the populations of stellar coronal sources in the Galaxy. With the
remarkable Chandra sensitivity and spatial resolution, ChaMPlane is
able to discover and locate sources with Lx ~1031 erg/s at distances
~3-10 kpc (depending on exposure) so that source populations on
Galactic scales can be studied for the first time.
ChaMPlane has now accumulated some 125 distinct fields (observed in
more than 200 pointings) that are observed with deep optical (V, R, I
and Halpha) images from a parallel Long Term Survey program supported
by NOAO (2001-2006). Deep near-infrared images (J, H and K) and
follow-up spectroscopy supported by a second NOAO Long Term Survey
(ChaMPlane-II) will be obtained beginning in 2007.
Three low-extinction Windows in the Galactic Bulge have been targeted
by the ChaMPlane Team to do deeper exposures together with HST/ACS
imaging (of the central 6.7 x 6.7 arcmin2 of the ACIS field). Baade's
Window was observed in 2003, "Stanek's Window" in 2004, and a
"Limiting Window" (the moderate extinction window closest to the
Galactic Center) in 2005.
Finally, the ChaMPlane Team is conducting a "Bulge Latitude Survey"
(BLS) to measure the latitude distribution of faint point sources in
the region |b| = ±1.5 deg, l = ±0.4deg centered at l = 0deg to
complement the previous survey of Wang et al. for the
longitude distribution of sources in the central Bulge.
Jonathan Grindlay (PI), Jaesub Hong, Silas Laycock,
Maureen van den Berg, Ping Zhao