GRB 061122: Optical Afterglow

GCN Circular #5849 GRB 061122: Candidate Optical Afterglow

J. P. Halpern & E. Armstrong (Columbia U.) report on behalf of the MDM Observatory GRB follow-up team: "We obtained R-band observations of the field of INTEGRAL GRB 061122 (Mereghetti et al., GCN 5834) on two consecutive nights using the MDM 2.4m telescope. Within 1" of the Swift XRT candidate X-ray afterglow (Beardmore et al., GCN 5842), we find a fading object at (J2000) R.A.=20h15m19.84s, Decl.=+15d31'02.5" with positional uncertainty ~0.5", and the following magnitudes: ------------------------------------------------ Date(UT) Mid-time(UT) t-t0(hr) R(mag) +/- ------------------------------------------------ Nov. 23 01:52 17.9 22.61 0.05 Nov. 24 02:26 42.5 23.41 0.15 ------------------------------------------------ We propose this as the optical afterglow of GRB 061122. Magnitudes are referenced to the USNO B1.0 star at (J2000) R.A.=20h15m18.48s, Decl.= +15d31'05.5" with R=17.61, and are not corrected for Galactic extinction, A_R=0.49 mag in this direction (Schlegel et al. 1998). MDM images of the field are posted at http://www.astro.columbia.edu/~jules/grb/061122/ This message may be cited."

(J2000) 20h 15m 19.8s, +15° 31′ 03″ (XRT 4&Prime radius)

MDM 2.4m R-band Nov. 23.08 UT

MDM 2.4m R-band Nov. 24.10 UT

GCN Circular #5852 GRB 061122: Confirmation of X-ray/ Optical Afterglow

DATE: 06/11/24 23:20:51 GMT FROM: Jules Halpern at Columbia U. In follow-up Swift XRT observations of INTEGRAL GRB 061122 (Mereghetti et al.,GCN 5834,5836) the X-ray source reported by Beardmore et al. (GCN 5842) as having 0.065 counts/s at 7 hr after the burst, has faded to 0.0047 counts/s averaged over the interval 18-55 hr post burst. Therefore, I regard this as confirmation of the X-ray afterglow as well as the coincident optical afterglow reported in GCN 5849.

Last Modified: November 24, 2006	jules@astro.columbia.edu