Details

Autor(en) / Beteiligte

• DEN BERG, Maureen Van
• PENNER, Kyle
• HONG, Jaesub
• GRINDLAY, Jonathan E
• PING ZHAO
• LAYCOCK, Silas
• SERVILLAT, Mathieu

Titel

THE ChaMPlane BRIGHT X-RAY SOURCES—GALACTIC LONGITUDES l = 2°-358

Ist Teil von

• The Astrophysical journal, 2012-03, Vol.748 (1), p.1-15

Ort / Verlag

Bristol: IOP

Erscheinungsjahr

2012

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• The Chandra Multi-wavelength Plane (ChaMPlane) survey aims to constrain the Galactic population of mainly accretion-powered, but also coronal, low-luminosity X-ray sources (L sub(X) [< ~] 10 super(33) erg s super(-1)). To investigate the X-ray source content in the plane at fluxes F sub(X) [> ~] 3 x 10 super(-14) erg s super(-1) cm super(-2), we study 21 of the brightest ChaMPlane sources, viz., those with >250 net counts (0.3-8 keV). By excluding the heavily obscured central part of the plane, our optical/near-infrared follow-up puts useful constraints on their nature. We have discovered two likely accreting white dwarf binaries. CXOPS J154305.5-522709 (CBS 7) is a cataclysmic variable showing periodic X-ray flux modulations on 1.2 hr and 2.4 hr; given its hard spectrum the system is likely magnetic. We identify CXOPS J175900.8-334548 (CBS 17) with a late-type giant; if the X-rays are indeed accretion powered, it belongs to the small but growing class of symbiotic binaries lacking strong optical nebular emission lines. CXOPS J171340.5-395213 (CBS 14) is an X-ray transient that brightened [> ~]100 times. We tentatively classify it as a very late type (>M7) dwarf, of which few have been detected in X-rays. The remaining sources are (candidate) active galaxies, normal stars and active binaries, and a plausible young T Tauri star. The derived cumulative number density versus flux (log N-log S) relation for the Galactic sources appears flatter than expected for an isotropic distribution, indicating that we are seeing a non-local sample of mostly coronal sources. Our findings define source templates that we can use, in part, to classify the > 10 super(4) fainter sources in ChaMPlane.