SAUNAS. I. Searching for Low Surface Brightness X-Ray Emission with Chandra/ACIS
Abstract
Abstract We present Selective Amplification of Ultra Noisy Astronomical Signal (SAUNAS), a pipeline designed for detecting diffuse X-ray emission in the data obtained with the Advanced CCD Imaging Spectrometer (ACIS) of the Chandra X-ray Observatory. SAUNAS queries the available observations in the Chandra archive and performs photometric calibration, point-spread function modeling and deconvolution, point-source removal, adaptive smoothing, and background correction. This pipeline builds on existing and well-tested software including CIAO, VorBin, and LIRA. We characterize the performance of SAUNAS through several quality performance tests and demonstrate the broad applications and capabilities of SAUNAS using two galaxies already known to show X-ray-emitting structures. SAUNAS successfully detects the 30 kpc X-ray superwind of NGC 3079 using Chandra/ACIS data sets, matching the spatial distribution detected with more sensitive XMM-Newton observations. The analysis performed by SAUNAS reveals an extended low surface brightness source in the field of UGC 5101 in the 0.3–1.0 keV and 1.0–2.0 keV bands. This source is potentially a background galaxy cluster or a hot gas plume associated with UGC 5101. SAUNAS demonstrates its ability to recover previously undetected structures in archival data, expanding exploration into the low surface brightness X-ray Universe with Chandra/ACIS.
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
The authors thank the anonymous referee for input that helped to improve this publication significantly. The SAUNAS X-ray surface brightness and signal-to-noise maps of NGC 3079 and UGC 5101 are publicly available in Zenodo in FITS format: DOI:10.5281/zenodo.10892485. This research has made use of data obtained from the Chandra Data Archive and the Chandra Source Catalog and software provided by the Chandra X-ray Center (CXC) in the application packages CIAO (Fruscione et al. 2006) and Sherpa (Freeman et al. 2001). The list of Chandra data sets, obtained by the Chandra X-ray Observatory, is contained in DOI:10.25574/cdc.225. A.B. acknowledges the tireless support from Nicholas Lee, Tara Gokas, Kenny Glotfelty, Catherine Cranmer, and the rest of the CXC Helpdesk team. Without your dedication, this project would have not been possible. A.S. acknowledges support from NASA contract to the Chandra X-ray Center NAS8-03060. The work conducted at NASA Ames Research Center was funded through NASA's NNH22ZDA001N Astrophysics Data and Analysis Program under award 22-ADAP22-0118. This work was authored by an employee of Caltech/IPAC under contract No. 80GSFC21R0032 with the National Aeronautics and Space Administration. This paper represents the views of the authors only and should not be interpreted as representing the views of ConstructConnect, Inc.
Facilities
CXO - Chandra X-ray Observatory satellite, HST - Hubble Space Telescope satellite
Software References
Matplotlib (Hunter 2007), CIAO, astropy (Astropy Collaboration et al. 2013, 2018, 2022), LIRA (Donath et al. 2022a), 27 VorBin (Cappellari & Copin 2003)
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Additional details
- ISSN
- 1538-4357
- National Aeronautics and Space Administration
- NAS8-03060
- National Aeronautics and Space Administration
- NNH22ZDA001N
- National Aeronautics and Space Administration
- 22-ADAP22-0118
- National Aeronautics and Space Administration
- 80GSFC21R0032
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)