Chandra Multiwavelength Project X-ray Point Source Number Counts and the Cosmic X-ray Background

Simple item page
dc.creatorKim, Minsun
dc.creatorWilkes, Belinda J.
dc.creatorKim, Dong-Woo
dc.creatorGreen, Paul J.
dc.creatorBarkhouse, Wayne A.
dc.creatorLee, Myung Gyoon
dc.creatorSilverman, John D.
dc.creatorTananbaum, Harvey D.
dc.date2006-11-28
dc.date.accessioned2026-07-07T11:42:40Z
dc.date.available2026-07-07T11:42:40Z
dc.descriptionWe present the Chandra Multiwavelength Project (ChaMP) X-ray point source number counts and the cosmic X-ray background (CXRB) flux densities in multiple energy bands. From the ChaMP X-ray point source catalog, ~5,500 sources are selected covering 9.6 deg^2 in sky area. To quantitatively characterize the sensitivity and completeness of the ChaMP sample, we perform extensive simulations. We also include the ChaMP+CDFs (Chandra Deep Fields) number counts to cover large flux ranges from 2x10^{-17} to 2.4x10^{-12} (0.5-2 keV) and from 2x10^{-16} to 7.1x10^{-12} (2-8 keV) erg/cm^2/sec. The ChaMP and the ChaMP+CDFs differential number counts are well fitted with a broken power law. The best fit faint and bright power indices are 1.49^{+0.02}_{-0.02} and 2.36^{+0.05}_{-0.05} (0.5-2 keV), and 1.58^{+0.01}_{-0.01} and 2.59^{+0.06}_{-0.05} (2-8 keV), respectively. We detect breaks in the differential number counts and they appear at different fluxes in different energy bands. Assuming a single power law model for a source spectrum, we find that the same population(s) of soft X-ray sources causes the break in the differential number counts for all energy bands. We measure the resolved CXRB flux densities from the ChaMP and the ChaMP+CDFs number counts with and without bright target sources. Adding the known unresolved CXRB to the ChaMP+CDF resolved CXRB, we also estimate total CXRB flux densities. The fractions of the resolved CXRB without target sources are 78^{+1}_{-1}% and 81^{+2}_{-2}% in the 0.5-2 keV and 2-8 keV bands, respectively, somewhat lower, though generally consistent with earlier numbers since their large errors. These fractions increase by ~1% when target sources are included.
dc.description54 pages, 21 figures, accepted for publication in ApJ, Full resolution version is available at http://hea-www.cfa.harvard.edu/CHAMP/RESULTS_PAPERS/ChaMP_ncounts.pdf
dc.identifierhttps://arxiv.org/abs/astro-ph/0611841
dc.identifierhttp://arxiv.org/abs/astro-ph/0611841
dc.identifierAstrophys.J.659:29-51,2007
dc.identifierdoi:10.1086/511630
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/200966
dc.subjectAstrophysics
dc.titleChandra Multiwavelength Project X-ray Point Source Number Counts and the Cosmic X-ray Background
dc.typetext

Files

Collections

arXiv