Chasing the Identification of ASCA Galactic Objects (ChIcAGO) - An X-ray Survey of Unidentified Sources in the Galactic Plane I: Source Sample and Initial Results

Abstract

We present the Chasing the Identification of ASCA Galactic Objects (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the F_x ~ 10^-13 to 10^-11 erg cm^-2 s^-1 X-ray flux range. In ChIcAGO, the subarcsecond localization capabilities of Chandra have been combined with a detailed multi-wavelength follow-up program, with the ultimate goal of classifying the >100 unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have been detected in these Chandra observations within 3' of the original ASCA positions. We have identified infrared and optical counterparts to the majority of these sources, using both new observations and catalogs from existing Galactic plane surveys. X-ray and infrared population statistics for the X-ray point sources detected in the Chandra observations reveal that the primary populations of Galactic plane X-ray sources that emit in the F_x ~ 10^-13 to 10^-11 erg cm^-2 s^-1 flux range are active stellar coronae, massive stars with strong stellar winds that are possibly in colliding-wind binaries, X-ray binaries, and magnetars. There is also a fifth population that is still unidentified but, based on its X-ray and infrared properties, likely comprise partly of Galactic sources and partly of active galactic nuclei.

52 pages, 20 figures, Accepted for publication in ApJ

References in corpus (35)

• The ATNF Pulsar Catalogue
• Fermi Large Area Telescope Bright Gamma-ray Source List
• The XMM-Newton Serendipitous Survey. V. The Second XMM-Newton Serendipitous Source Catalogue
• The VLA Galactic Plane Survey
• Catalogue of high-mass X-ray binaries in the Galaxy ($4^{th}$ edition)
• Search for Associations Containing Young stars (SACY): I. Sample & Searching Method
• The 3rd IBIS/ISGRI soft gamma-ray survey catalog
• The Molonglo Galactic Plane Survey (MGPS-2): Compact Source Catalogue
• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• Unveiling supergiant fast X-ray transient sources with INTEGRAL
• INTEGRAL/IBIS all-sky survey in hard X-rays
• An XMM-Newton view of the young open cluster NGC 6231 -- II. The OB star population
• The young stellar population in M17 revealed by Chandra
• The Southern Galactic Plane Survey: Polarized Radio Continuum Observations and Analysis
• The Compact X-ray Source 1E 1547.0-5408 and the Radio Shell G327.24-0.13: A New Proposed Association between a Candidate Magnetar and a Candidate Supernova Remnant
• Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2
• A Chandra Search for Coronal X Rays from the Cool White Dwarf GD 356
• High precision X-ray logN-logS distributions: implications for the obscured AGN population
• Pulsar Timing for the Fermi Gamma-ray Space Telescope
• IGR J16194-2810: a new symbiotic X-ray binary
• The Anatomy of a Magnetar: XMM Monitoring of the Transient Anomalous X-ray Pulsar XTE J1810-197
• XMM-Newton observations of the Small Magellanic Cloud: Be/X-ray binary pulsars active between October 2006 and June 2007
• A search for counterparts to massive X-ray binaries using photometric catalogues
• Searching for hidden Wolf-Rayet stars in the Galactic Plane - 15 new Wolf-Rayet stars
• X-ray emission from PSR J1809-1917 and its pulsar wind nebula, possibly associated with the TeV gamma-ray source HESS J1809-193
• XMM-Newton observations reveal the X-ray counterpart of the very-high-energy gamma-ray source HESSJ1640-465
• The (Re-)Discovery of G350.1-0.3: A Young, Luminous Supernova Remnant and Its Neutron Star
• Chandra monitoring of the very massive binary WR20a and the young massive cluster Westerlund2
• Discovery of a Young, Energetic 70.5 ms Pulsar Associated with the TeV Gamma-ray Source HESS J1837-069
• Orbital Parameters for the X-ray Pulsar IGR J16393-4643
• AX J1910.7+0917 and three newly discovered INTEGRAL sources
• XMM-Newton Discovery of the X-ray Transient XMMU J181227.8-181234 in the Galactic Plane
• XMM detection of the supernova remnant G337.2+0.1
• The nature of the compact HII region Sh 2-89 and its stellar content
• The nature of the ASCA/INTEGRAL source AX J183039-1002: a new Compton-thick AGN?

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