TY - JOUR
T1 - Parallel tracks in infrared versus X-ray emission in black hole X-ray transient outbursts
T2 - A hysteresis effect?
AU - Russell, David M.
AU - MacCarone, Thomas J.
AU - Körding, Elmar G.
AU - Homan, Jeroen
PY - 2007/8
Y1 - 2007/8
N2 - We report the discovery of a new hysteresis effect in black hole X-ray binary state transitions, that of the near-infrared (NIR) flux (which most likely originates in the jets) versus X-ray flux. We find, looking at existing data sets, that the IR emission of black hole X-ray transients appears to be weaker in the low/hard state rise of an outburst than the low/hard state decline of an outburst at a given X-ray luminosity. We discuss how this effect may be caused by a shift in the radiative efficiency of the inflowing or outflowing matter, or variations in the disc viscosity or the spectrum/power of the jet. In addition we show that there is a correlation (in slope but not in normalization) between IR and X-ray luminosities on the rise and decline, for all three low-mass black hole X-ray binaries with well-sampled IR and X-ray coverage: LNIR ∝ L0.5-0.7X. In the high/soft state this slope is much shallower; LNIR ∝ L0.1-0.2X, and we find that the NIR emission in this state is most likely dominated by the viscously heated (as opposed to X-ray heated) accretion disc in all three sources.
AB - We report the discovery of a new hysteresis effect in black hole X-ray binary state transitions, that of the near-infrared (NIR) flux (which most likely originates in the jets) versus X-ray flux. We find, looking at existing data sets, that the IR emission of black hole X-ray transients appears to be weaker in the low/hard state rise of an outburst than the low/hard state decline of an outburst at a given X-ray luminosity. We discuss how this effect may be caused by a shift in the radiative efficiency of the inflowing or outflowing matter, or variations in the disc viscosity or the spectrum/power of the jet. In addition we show that there is a correlation (in slope but not in normalization) between IR and X-ray luminosities on the rise and decline, for all three low-mass black hole X-ray binaries with well-sampled IR and X-ray coverage: LNIR ∝ L0.5-0.7X. In the high/soft state this slope is much shallower; LNIR ∝ L0.1-0.2X, and we find that the NIR emission in this state is most likely dominated by the viscously heated (as opposed to X-ray heated) accretion disc in all three sources.
KW - Accretion, accretion discs
KW - Black hole physics
KW - X-rays: binaries
UR - http://www.scopus.com/inward/record.url?scp=34547761779&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2007.11996.x
DO - 10.1111/j.1365-2966.2007.11996.x
M3 - Article
AN - SCOPUS:34547761779
SN - 0035-8711
VL - 379
SP - 1401
EP - 1408
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -