Morehead State University
Searching for Time Variability in the X-ray Emission from the Discrete Source Population of the Nearby Galaxy NGC 55 as Revealed by the Chandra X-ray Observatory
Institution
Morehead State University
Faculty Advisor/ Mentor
Thomas Pannuti
Abstract
X-ray observations of nearby galaxies reveal classes of sources - such as x-ray binaries, galactic nuclei, and background galaxies - that are known to exhibit time dependence in their x-ray emission. To help characterize the discrete x-ray sources detected toward the nearby galaxy NGC55 by the ChandraX-Ray Observatory we have searched for evidence of time variability using the standard tool "glvary", the Gregory-Loredo algorithm based in Bayesian statistics. We have identified two sources which show robust evidence for variability during the sixty kilosecond observation: one source (CXOU J001502.2-391425,0) appears to be physcially associated with the galaxy and may be a resident X-ray binary while the other source (CXOU J001438.5-391241) appears to be seen outside of NGC 55 and is likely to be a background galaxy. We describe our analysis and methods as well as our initial results.
Searching for Time Variability in the X-ray Emission from the Discrete Source Population of the Nearby Galaxy NGC 55 as Revealed by the Chandra X-ray Observatory
X-ray observations of nearby galaxies reveal classes of sources - such as x-ray binaries, galactic nuclei, and background galaxies - that are known to exhibit time dependence in their x-ray emission. To help characterize the discrete x-ray sources detected toward the nearby galaxy NGC55 by the ChandraX-Ray Observatory we have searched for evidence of time variability using the standard tool "glvary", the Gregory-Loredo algorithm based in Bayesian statistics. We have identified two sources which show robust evidence for variability during the sixty kilosecond observation: one source (CXOU J001502.2-391425,0) appears to be physcially associated with the galaxy and may be a resident X-ray binary while the other source (CXOU J001438.5-391241) appears to be seen outside of NGC 55 and is likely to be a background galaxy. We describe our analysis and methods as well as our initial results.