A Transient Black-Hole Low-Mass X-Ray Binary Candidate in Centaurus A

Abstract

We report the discovery of a bright transient X-ray source, CXOU J132518.2-430304, towards Centaurus A (Cen A) using six new Chandra X-Ray Observatory observations in 2007 March--May. Between 2003 and 2007, its flux has increased by a factor of >770. The source is likely a low-mass X-ray binary in Cen A with unabsorbed 0.3-10 keV band luminosities of (2-3) x 10^{39} erg s^-1 and a transition from the steep-power law state to the thermal state during our observations. CXOU J132518.2-430304 is the most luminous X-ray source in an early-type galaxy with extensive timing information that reveals transience and a spectral state transition. Combined with its luminosity, these properties make this source one of the strongest candidates to date for containing a stellar-mass black hole in an early-type galaxy. Unless this outburst lasts many years, the rate of luminous transients in Cen A is anomalously high compared to other early-type galaxies.

Corrected Minor Typo in Figure. Accepted by Astrophysical Journal Letters, 4 pages, 1 Color Figures, 2 B & W Figures (1 degraded): Full resolution paper available at http://www.astronomy.ohio-state.edu/~sivakoff/CenA/CenA_Transient_BH_LMXB.pdf

References in corpus (16)

• X-ray Properties of Black-Hole Binaries
• The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances
• Catalogue of high-mass X-ray binaries in the Galaxy ($4^{th}$ edition)
• The distances to Galactic low-mass X-ray binaries: consequences for black hole luminosities and kicks
• Resolving the Mystery of X-ray Faint Elliptical Galaxies: Chandra X-ray Observations of NGC 4697
• The Low-Mass X-ray Binary and Globular Cluster Connection in Virgo Cluster Early-type Galaxies: Optical Properties
• The Discovery of Cepheids and a Distance to NGC 5128
• The Lack of Very Ultraluminous X-ray Sources in Early-type Galaxies
• New results on particle acceleration in the Centaurus A jet and counterjet from a deep Chandra observation
• A study of the population of LMXBs in the bulge of M31
• Low-Mass X-ray Binaries and Globular Clusters in Centaurus A
• A Catalog of Transient X-ray Sources in M31
• Where Centaurus A gets its X-ray knottiness
• The Remarkable Stability of Probable Black Hole Low-Mass X-ray Binaries in Nearby Galaxies
• Bright X-ray Transients in M31: 2004 July XMM-Newton Observations
• On the nature of the ultraluminous X-ray transient in Cen~A (NGC 5128)

Cited by in corpus (20)

• Innovations in the Analysis of Chandra-ACIS Observations
• High-energy particle acceleration at the radio-lobe shock of Centaurus A
• The X-ray Jets of Active Galaxies
• Optical counterparts of the nearest ultraluminous X-ray sources
• The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source
• The Birth of an Ultra-Luminous X-ray Source in M83
• Long Term Monitoring of the Dynamics and Particle Acceleration of Knots in the Jet of Centaurus A
• Near-infrared counterparts of ultraluminous X-ray sources
• A Variable Black Hole X-Ray Source in a NGC 1399 Globular Cluster
• Luminosity functions of LMXBs in Centaurus A: globular clusters versus the field
• NGC 2276: a remarkable galaxy with a large number of ULXs
• Uncovering Red and Dusty Ultraluminous X-ray Sources with Spitzer
• A new Ultraluminous X-ray source in the galaxy NGC 5907
• Discovery of a 6.4 h black hole binary in NGC 4490
• Discovery of a transient ultraluminous X-ray source in the elliptical galaxy M86
• Swift observations of the ultraluminous X-ray source XMMU J004243.6+412519 in M31
• Spectral transitions of an ultraluminous X-ray source, NGC 2403 Source 3
• The fading of two transient ULXs to below the stellar mass Eddington limit
• Spectral Properties of X-ray Binaries in Centaurus A
• A Transient Sub-Eddington Black Hole X-ray Binary Candidate in the Dust Lanes of Centaurus A