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NGC 1291 Chandra X-Ray Point Source Catalog

Metadata Updated: April 10, 2026

This table contains some of the results from a study of the X-ray binary (XRB) populations in the bulge and ring regions of the ring galaxy NGC 1291. Utilizing the four available Chandra observations totaling an effective exposure of 179 ks, the authors detect 169 X-ray point sources in the galaxy in the full band (0.3 - 8.0 keV) with a false-positive probability threshold of 10<sup>-6</sup> (implying approximately 2 false detections given the size of the image). Of these sources, 75 are in the bulge and 71 are in the ring. The authors report photometric properties of these sources in a point-source catalog. There are ~ 40% of the bulge sources and ~ 25% of the ring sources showing > 3-sigma long-term variability in their X-ray count rate. The X-ray colors suggest that a significant fraction of the bulge (~ 75%) and ring (~ 65%) sources are likely low-mass X-ray binaries (LMXBs). The spectra of the nuclear source indicate that it is a low-luminosity active galactic nucleus (AGN) with moderate obscuration; spectral variability is observed between individual observations. The authors construct 0.3-8.0 keV X-ray luminosity functions (XLFs) for the bulge and ring XRB populations, taking into account the detection incompleteness and background AGN contamination. They reach 90% completeness limits of ~ 1.5 x 10<sup>37</sup> and ~ 2.2 x 10<sup>37</sup> erg s<sup>-1</sup> for the bulge and ring populations, respectively. Both XLFs can be fit with a broken power-law model, and the shapes are consistent with those expected for populations dominated by LMXBs. In the paper, the authors perform detailed population synthesis modeling of the XRB populations in NGC 1291, which suggests that the observed combined XLF is dominated by an old LMXB population. They compare the bulge and ring XRB populations, and argue that the ring XRBs are associated with a younger stellar population than the bulge sources, based on the relative overdensity of X-ray sources in the ring, the generally harder X-ray color of the ring sources, the overabundance of luminous sources in the combined XLF, and the flatter shape of the ring XLF. This table was created by the HEASARC in May 2012 based on an electronic version of Table 2 from the reference paper obtained from the ApJ website. This is a service provided by NASA HEASARC .

Access & Use Information

Public: This dataset is intended for public access and use. License: See this page for license information.

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Dates

Metadata Created Date April 11, 2025
Metadata Updated Date April 10, 2026

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date April 10, 2026
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/ngc1291cxo
Data Last Modified 2026-04-06
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id af278792-70d0-4f57-8826-971e596a242b
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL ivo://nasa.heasarc/ngc1291cxo
License https://www.usa.gov/government-works
Program Code 026:000
Source Datajson Identifier True
Source Hash 62569148b0f7d66e916e37804854cbd44372780e0d5a855c3690f6d0193a68f9
Source Schema Version 1.1

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