[vsnet-grb-info 5984] Swift XRT and UVOT observations of GRB080414

GCN Circulars gcncirc at capella.gsfc.nasa.gov
Thu Apr 17 22:02:04 JST 2008


TITLE:   GCN CIRCULAR
NUMBER:  7628
SUBJECT: Swift XRT and UVOT observations of GRB080414
DATE:    08/04/17 13:01:50 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp at mssl.ucl.ac.uk>

   M. De Pasquale (MSSL/UCL), A.P. Beardmore (U. Leicester) and M.
Stamatikos (GSFC) report on the behalf of the Swift team:

  At 2008-04-15 14:15UT Swift performed a TOO observation of the INTEGRAL
burst GRB 080414 (Mereghetti et al., GCN Circ. 7618), some 56.6ks after
the trigger.

   No X-ray source was found in or near the IBAS error circle in a 3.9ks
exposure Swift/XRT Photon Counting mode image (taken from T+56ks to
T+85.5ks after the trigger) down to a 3 sigma limiting 0.3-10keV count
rate of 3e-3 count/s. Assuming a power-law spectrum of photon index 2
absorbed by the Galactic column density of 1.16e22 cm^-2 in the direction
of the burst, this corresponds to an observed 0.3-10keV flux limit of
1.9e-13 erg cm^-2 s^-1.


   The Swift/UVOT also observed the field. We do not detect an UV/Optical
afterglow in the IBAS error circle in all UVOT filters down to the
following 5 sigma upper limits:

   Filter  T_start  T_stop  Exp.    Mag UL (5sig)
           (ks)     (ks)    (s)

   v       56.9     79.9    272     > 18.3
   b       56.7     79.5    272     > 19.4
   u       56.7     84.7    326     > 19.2
   uvw1    56.6     84.7   1001     > 19.9
   uvm2    57.0     80.1    564     > 19.4
   uvw2    56.8     79.8   1085     > 19.9

   These upper limits are not corrected for the very large Galactic
extinction in the line of sight to GRB 080414, corresponding to a
reddening of E(B-V)=6.95 mag (Schlegel et al., 1998, ApJS, 500, 525). We
note that this value is rather uncertain in this direction.
The photometry is based on the UVOT photometric system described in Poole
et al. (2008, MNRAS, 383, 627).


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