Optical and infrared monitoring of SWIFT J1753.3-0127

ATel #566; M. A.P. Torres, D. Steeghs, C. Blake, P. G.Jonker, M. R.Garcia, J. E.McClintock, J. Miller, P. Zhao, M. Calkins, P. Berlind, E. Falco (Harvard-Smithsonian), J. Bloom (UCB), P. Callanan (Univ. Cork), P. Rodriguez-Gil (IAC)
on 14 Jul 2005; 20:05 UT
Credential Certification: Danny Steeghs (dsteeghs@cfa.harvard.edu)

Tweet

We report preliminary optical/infrared photometry and spectroscopy of the SWIFT J1753.3-0127 transient (ATEL #546, #549) obtained at Fred Whipple Observatory (FLWO), Mt. Hopkins, AZ.

Nightly R-band photometry was acquired with the FLWO 1.2m telescope between July 2-11 2005 UT achieving a PSF FWHM of 1.8-2.8 arcsec and typically using 60s exposure times. The images were calibrated using Landolt standard stars. The counterpart showed night to night variability at a level of 0.05-0.1 mag, ranging between 15.6 < R < 15.8 mag during the July 2-11 interval. On top of this variability, a slow decline is suggested at a level of ~0.1 mag per week.

Optical spectroscopy was acquired on July 7,10,11,12 2005 UT with the FAST spectrograph attached to the 1.5m telescope, covering 3700-7500 Angstrom with a resolution of <4.5 Angstrom. Broad, double-peaked Halpha emission was detected each night with mean EW of 3 Angstrom, mean double-peak separation of 1200 km/s and FWHM~2000 km/s (see also ATEL #551). HeII4686 emission was highly variable both in terms of strength and profile shape ranging between ~3 and ~5 Angstrom in EW.

Near-infrared photometry was acquired using the 1.3m robotic Pairitel telescope on July 11 2005 UT. A point source was detected at the position of the optical counterpart with J=15.1, H=14.8, K=14.3 based on nearby 2MASS sources. No source is present in the 2MASS archive at this position.