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Chandra Multiwavelength Plane Survey


The Chandra Multiwavelength Plane (ChaMPlane) Survey is designed to measure or constrain the populations of low-luminosity (LX > ~1031 ergs s-1) accreting white dwarfs, neutron stars, and stellar mass black holes in the Galactic plane and bulge. ChaMPlane incorporates two surveys, X-ray (Chandra) and optical (NOAO 4-m Mosaic imaging), and a follow-up spectroscopy and IR identification program. The survey extends through the first 6 yr of Chandra data using serendipitous sources detected in 105 distinct ACIS-I and ACIS-S fields observed in 154 pointings and covered by 65 deep Mosaic images in V, R, I, and Hα. ChaMPlane incorporates fields with Galactic latitude b < ~12° and selected to be devoid of bright point or diffuse sources, with exposure time > ~20 ks and (where possible) minimum NH.

The optical image portion of ChaMPlane was an NOAO Survey project to conduct the optical identification survey for ChaMPlane sources with a deep imaging survey using the NOAO 4-m telescopes at CTIO and KPNO. The target fields were observed with the MOSAIC imager (36' x36'), so that the entire Chandra ACIS-I (or ACIS-S) field was covered. The NOAO optical survey for ChaMPlane is the deepest Hα survey of portions of the galactic plane, and covers ~ 4 x the area of the enclosed Chandra ChaMPlane survey for which it provides the primary identifications. The ChaMPlane NOAO imaging survey serves two purposes:

  1. provide images for identifying the optical counterparts of Chandra sources and measure their V, R, I, Hα magnitudes to enable approximate spectral classification and constraints on reddening
  2. identify Hα emission objects (by comparison of their magnitudes in Hα vs. R filters) as well as to measure their V, R, and I magnitudes. Deep (R ~ 24) 4-m Mosaic images are obtained to identify CVs and qLMXBs by their ubiquitous Hα excess as “blue” objects in the R vs. (Hα - R) diagram.

ChaMPlane at a Glance

PI(s) Josh Grindlay
Proposal ID 2000B-0036
Years of Observation 2000-2004
Area covered: 65 fields within 12° of the galactic plane
Bands V, Hα, R, I
Median Depth (5σ) (V, Hα, R, I) = (22.8, 22.2, 22.7, 20.9)
Median Seeing (V, Hα, R, I) = (1.4, 1.2, 1.3, 1.3) arcsec
Number of images 1429