233 X-ray sources in omega Centauri Virtual Observatory Resource

Authors
  1. Henleywillis S.
  2. Cool A.M.
  3. Haggard D.
  4. Heinke C.
  5. Callanan P.
  6. Zhao Y.
  7. Published by
    CDS
Abstract

We identify 233 X-ray sources, of which 95 are new, in a 222ks exposure of omega Centauri with the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer detector. The limiting unabsorbed flux in the core is fX(0.5-6.0keV)~=3x10^-16^erg/s/cm^2^ (Lx~=1x10^30^erg/s at 5.2kpc). We estimate that ~60+/-20 of these are cluster members, of which ~30 lie within the core (r_c_=155-arcsec), and another ~30 between 1-2 core radii. We identify four new optical counterparts, for a total of 45 likely identifications. Probable cluster members include 18 cataclysmic variables (CVs) and CV candidates, one quiescent low-mass X-ray binary, four variable stars, and five stars that are either associated with omega Cen's anomalous red giant branch or are sub-subgiants. We estimate that the cluster contains 40+/-10 CVs with Lx>10^31^erg/s, confirming that CVs are underabundant in omega Cen relative to the field. Intrinsic absorption is required to fit X-ray spectra of six of the nine brightest CVs, suggesting magnetic CVs, or high-inclination systems. Though no radio millisecond pulsars (MSPs) are currently known in omega Cen, more than 30 unidentified sources have luminosities and X-ray colours like those of MSPs found in other globular clusters; these could be responsible for the Fermi-detected gamma-ray emission from the cluster. Finally, we identify a CH star as the counterpart to the second brightest X-ray source in the cluster and argue that it is a symbiotic star. This is the first such giant/white dwarf binary to be identified in a globular cluster.

Keywords
  1. globular-star-clusters
  2. x-ray-sources
Bibliographic source Bibcode
2018MNRAS.479.2834H
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/479/2834
IVOA Identifier IVOID
ivo://CDS.VizieR/J/MNRAS/479/2834

Access

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http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/479/2834
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/479/2834
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/479/2834
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Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
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http://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/479/2834/table1?
https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/479/2834/table1?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/479/2834/table1?

History

2019-03-15T12:28:54Z
Resource record created
2019-03-15T12:28:54Z
Created
2019-03-26T14:40:17Z
Updated

Contact

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CDS support team
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