The Infrared Counterpart of the X-Ray Nova XTE J1720-318

Abstract

We report on the discovery of an infrared counterpart to the X-ray transient XTE J1720-318 on 2003 January 18, nine days after an X-ray outburst, and the infrared light curve during the first 130 days after the outburst. The infrared light curve shows a decline of about 1.2 mag from the peak magnitude of Ks about 15.3 over the observation period, and a secondary maximum, about 40 days after the outburst. Another small increase in the flux was also recorded about 20 days after the outburst. These increases were also detected in the X-ray light curve. The J H Ks colors are consistent with an X-ray irradiated accretion disk suffering an extinction of Av about 8, which is also inferred from its X-ray spectrum and the extinction map constructed from far-infrared dust emission of this line of sight. These J, H, and Ks observations demonstrate that useful data can be obtained even for such an object, which suffers heavy optical extinction, possibly located beyond the Galactic center.

5 pages, 2 figures, to appear in PASJ

References in corpus (2)

• Extinction within 10 degrees of the Galactic Centre using 2MASS
• The origin of the rebrightening in soft X-ray transient outbursts

Cited by in corpus (7)

• BlackCAT: A catalogue of stellar-mass black holes in X-ray transients
• Global optical/infrared - X-ray correlations in X-ray binaries: quantifying disc and jet contributions
• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Variable Star Network: World Center for Transient Object Astronomy and Variable Stars
• The INTEGRAL view on Black Hole X-ray Binaries
• Optical/near-infrared observations of the black hole candidate XTE J1720-318: from high-soft to low-hard state
• A thin diffuse component of the Galactic Ridge X-ray emission and heating of the interstellar medium contributed by the radiation of Galactic X-ray binaries