eBASCS: disentangling overlapping astronomical sources II, using
spatial, spectral, and temporal information
spatial, spectral, and temporal information
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The analysis of individual X-ray sources that appear in a crowded field can easily be compromised by the misallocation of recorded events to their originating sources. Even with a small number of sources, which none the less have overlapping point spread functions, the allocation of events to sources is a complex task that is subject to uncertainty. We develop a Bayesian method designed to sift high-energy photon events from multiple sources with overlapping point spread functions, leveraging the differences in their spatial, spectral, and temporal signatures. The method probabilistically assigns each event to a given source. Such a disentanglement allows more detailed spectral or temporal analysis to focus on the individual component in isolation, free of contamination from other sources or the background. We are also able to compute source parameters of interest like their locations, relative brightness, and background contamination, while accounting for the uncertainty in event assignments. Simulation studies that include event arrival time information demonstrate that the temporal component improves event disambiguation beyond using only spatial and spectral information. The proposed methods correctly allocate up to 65 per cent more events than the corresponding algorithms that ignore event arrival time information. We apply our methods to two stellar X-ray binaries, UV Cet and HBC 515 A, observed with Chandra. We demonstrate that our methods are capable of removing the contamination due to a strong flare on UV Cet B in its companion ≈40× weaker during that event, and that evidence for spectral variability at times-scales of a few ks can be determined in HBC 515 Aa and HBC 515 Ab.
Date Issued
2021-10-01
Date Acceptance
2021-05-18
Citation
Monthly Notices of the Royal Astronomical Society, 2021, 506 (4), pp.6160-6180
ISSN
0035-8711
Publisher
Royal Astronomical Society
Start Page
6160
End Page
6180
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
506
Issue
4
Copyright Statement
©The Author(s) 2021.Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium,provided the original work is properly cited
License URL
Sponsor
National Science Foundation (US)
European Commission
Identifier
http://arxiv.org/abs/2105.08606v1
Grant Number
DMS 15-13484
H2020-MSCA-RISE-2015-691164
Subjects
astro-ph.IM
astro-ph.IM
stat.AP
Publication Status
Published
Date Publish Online
2021-06-07