Optical observations of Swift J1822.3-1606 with the 10.4m Gran Telescopio Canarias
ATel #3515; N. Rea (CSIC-IEEC, Barcelona), R. P. Mignani (MSSL-UCL), G. L. Israel (INAF-OARoma), P. Esposito (INAF-OACagliari) report on behalf of a larger collaboration
on 28 Jul 2011; 09:23 UT
Credential Certification: Nanda Rea (rea@ieec.uab.es)
Subjects: Optical, X-ray, Soft Gamma-ray Repeater, Transient
Referred to by ATel #: 3518
We observed the field of the new Soft Gamma-ray Repeater (SGR), Swift J1822.3-1606 (Cummings et al., Atel #3488) with the 10.4m Gran Telescopio Canarias (GranTeCan). Images have been taken with the OSIRIS camera, a two-chip CCD with a nominal 7.8'x7.8' arcmin field of view and a pixel size of 0.125". Observations have been taken in the z-Sloan-band on 2011 July 21st (unfortunately in bright lunar time, with a large sky background and a seeing ranging from 1-2.5") with exposure times of 54-108s. We confirmed the detection of the three objects (S1, S2, S3) within or close to the XRT error circle, as reported by Gorosabel et al. (Atel #3496). They had z-magnitudes of S1=18.13+/-0.16, S2=20.05 +/-0.04, and S3= 19.94 +/- 0.04 . No other dim object has been detected consistent with the refined X-ray position of Swift 1822.3-1606 (Pagani et al., Atel #3493), down to a 3-sigma limiting magnitude of z=22.2 +/-0.2 . Given their bright optical magnitudes, we doubt any of those objects being the optical counterpart to this SGR.
We acknowledge the extraordinary support of the GTC staff, and in particular Rene Rutten and Carlos Alvarez for the prompt reaction to our ToO trigger.
