Analysis of Off-Nuclear X-Ray Sources in Galaxy NGC 4945

Harrison, Sarah M. ; /SLAC, /MIT

Stanford Linear Accelerator Center

关键词: Bremsstrahlung;    Quasars;    Energy Spectra;    Neutron Stars;    Galaxies;   

DOI  :  10.2172/908225
RP-ID  :  SLAC-TN-06-019
RP-ID  :  AC02-76SF00515
RP-ID  :  908225

美国|英语

来源: UNT Digital Library

【 摘 要 】

Recently, X-ray astronomy has been used to investigate objects such as galaxies, clusters of galaxies, Active Galactic Nuclei (AGN), quasars, starburst superbubbles of hot gas, X-ray binary systems, stars, supernova remnants, and interstellar and intergalactic material. By studying the x-ray emission patterns of these objects, we can gain a greater understanding of their structure and evolution. We analyze X-ray emission from the galaxy NGC 4945 using data taken by the Chandra X-ray Observatory. The Chandra Interactive Analysis of Observations (CIAO) software package was used to extract and fit energy spectra and to extract light curves for the brightest off-nuclear sources in two different observations of NGC 4945 (January, 2000 and May, 2004). A majority of sources were closely fit by both absorbed power law and absorbed bremsstrahlung models, with a significantly poorer {chi}{sup 2}/dof for the absorbed blackbody model, and most sources had little variability. This indicates that the sources are accreting binary systems with either a neutron star or black hole as the compact object. The calculated luminosities were about 10{sup 38} erg/s, which implies that the mass of the accreting object is close to 10 solar masses and must be a black hole.