Columbia University Astronomy and 
Astrophysics


MDM Observatory GRB Team


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
MDM 2.4m R-band Nov. 23.08 UT

MDM 2.4m
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.

Eve Armstrong
earmstrong@physics.ucsd.edu
Jules Halpern
jules@astro.columbia.edu
Nestor Mirabal
mirabal@astro.columbia.edu
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Last Modified: November 24, 2006 jules@astro.columbia.edu