TY - JOUR
T1 - Very Large Telescope/X-shooter Spectroscopy of the Candidate Black Hole X-Ray Binary MAXI J1659-152 in Outburst
AU - Kaur, R.
AU - Kaper, L.
AU - Ellebroek, L.E.
AU - Russell, D.M.
AU - Altmirano, D.
AU - Wijnands, R.
AU - Yang, Yi-Jung
AU - D'Avanzo, P.
AU - Fynbo, Johan Peter Uldall
AU - Ugarte Postigo, Antonio de
AU - Thöne, Christina
AU - Goldoni, P.
PY - 2012/2/20
Y1 - 2012/2/20
N2 - We present the optical to near-infrared spectrum of MAXI J1659-152 during the onset of its 2010 X-ray outburst. The spectrum was obtained with X-shooter on the ESO Very Large Telescope early in the outburst simultaneous with high-quality observations at both shorter and longer wavelengths. At the time of the observations, the source was in the low-hard state. The X-shooter spectrum includes many broad (∼2000kms-1), double-peaked emission profiles of H, He I, and He II, characteristic signatures of a low-mass X-ray binary during outburst. We detect no spectral signatures of the low-mass companion star. The strength of the diffuse interstellar bands results in a lower limit to the total interstellar extinction of AV ≃ 0.4mag. Using the neutral hydrogen column density obtained from the X-ray spectrum we estimate AV ≃ 1mag. The radial velocity structure of the interstellar Na I D and Ca II H&K lines results in a lower limit to the distance of ∼4± 1kpc, consistent with previous estimates. With this distance and AV, the dereddened spectral energy distribution represents a flat disk spectrum. The two 10 minute X-shooter spectra show significant variability in the red wing of the emission-line profiles, indicating a global change in the density structure of the disk, though on a timescale much shorter than the typical viscous timescale of the disk.
AB - We present the optical to near-infrared spectrum of MAXI J1659-152 during the onset of its 2010 X-ray outburst. The spectrum was obtained with X-shooter on the ESO Very Large Telescope early in the outburst simultaneous with high-quality observations at both shorter and longer wavelengths. At the time of the observations, the source was in the low-hard state. The X-shooter spectrum includes many broad (∼2000kms-1), double-peaked emission profiles of H, He I, and He II, characteristic signatures of a low-mass X-ray binary during outburst. We detect no spectral signatures of the low-mass companion star. The strength of the diffuse interstellar bands results in a lower limit to the total interstellar extinction of AV ≃ 0.4mag. Using the neutral hydrogen column density obtained from the X-ray spectrum we estimate AV ≃ 1mag. The radial velocity structure of the interstellar Na I D and Ca II H&K lines results in a lower limit to the distance of ∼4± 1kpc, consistent with previous estimates. With this distance and AV, the dereddened spectral energy distribution represents a flat disk spectrum. The two 10 minute X-shooter spectra show significant variability in the red wing of the emission-line profiles, indicating a global change in the density structure of the disk, though on a timescale much shorter than the typical viscous timescale of the disk.
U2 - 10.1088/2041-8205/746/2/L23
DO - 10.1088/2041-8205/746/2/L23
M3 - Journal article
SN - 0004-637X
VL - 746
SP - L23
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -