The First Low-Mass Black Hole X-Ray Binary Identified in Quiscence Outside of a Globular Cluster
Artikel i vetenskaplig tidskrift, 2016

The observed relation between the X-ray and radio properties of low-luminosity accreting black holes (BHs) has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters (GCs). Here, we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al., as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a - + 2.2 0.30.5 kpc distance, which identifies it as lying in the foreground of the GC M15. We determine the radio characteristics of this source and place a deep limit on the X-ray luminosity of ∼4 × 1029 erg s.1. Furthermore, we astrometrically identify a faint red stellar counterpart in archival Hubble images with colors consistent with a foreground star; at 2.2 kpc, its inferred mass is 0.1-0.2Me. We rule out that this object is a pulsar, neutron star X-ray binary, cataclysmic variable, or planetary nebula, concluding that VLA J213002.08+120904 is the first accreting BHXB candidate discovered in quiescence outside of a GC. Given the relatively small area over which parallax studies of radio sources have been performed, this discovery suggests a much larger population of quiescent BHXBs in our Galaxy, 2.6 ± 104-1.7 × 108 BHXBs at 3× confidence, than has been previously estimated (∼102-104) through population synthesis.The observed relation between the X-ray and radio properties of low-luminosity accreting black holes (BHs) has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters (GCs). Here, we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al., as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a - + 2.2 0.30.5 kpc distance, which identifies it as lying in the foreground of the GC M15. We determine the radio characteristics of this source and place a deep limit on the X-ray luminosity of ∼4 × 1029 erg s.1. Furthermore, we astrometrically identify a faint red stellar counterpart in archival Hubble images with colors consistent with a foreground star; at 2.2 kpc, its inferred mass is 0.1-0.2Me. We rule out that this object is a pulsar, neutron star X-ray binary, cataclysmic variable, or planetary nebula, concluding that VLA J213002.08+120904 is the first accreting BHXB candidate discovered in quiescence outside of a GC. Given the relatively small area over which parallax studies of radio sources have been performed, this discovery suggests a much larger population of quiescent BHXBs in our Galaxy, 2.6 ± 104-1.7 × 108 BHXBs at 3× confidence, than has been previously estimated (∼102-104) through population synthesis.

black hole physics

stars: individual (VLA J213002.08+120904)

X-rays: binaries

radio continuum: general

Författare

B. E. Tetarenko

University of Alberta

A. Bahramian

University of Alberta

R. M. Arnason

Western University

University of Alberta

J. C. A. Miller-Jones

Curtin University

S. Repetto

Technion – Israel Institute of Technology

Radboud Universiteit

C. O. Heinke

University of Alberta

T. J. Maccarone

Texas Tech University at Lubbock

L. Chomiuk

Michigan State University

G. R. Sivakoff

University of Alberta

J. Strader

Michigan State University

F. Kirsten

Curtin University

Wouter Vlemmings

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 825 1 10

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.3847/0004-637X/825/1/10