Skip to main content
New Swift-BAT/GUANO and IceCube Notice Types Available! See news and announcements

GCN Circular 2716

Subject
GRB040912(=H3557): Observations with the Chandra X-ray Observatory
Date
2004-09-16T18:21:46Z (19 years ago)
From
Roland Vanderspek at MIT <roland@space.mit.edu>
GRB040912(=H3557): Observations with the Chandra X-ray Observatory

N. Butler, P. Ford, G. Ricker, R. Vanderspek, J. Villasenor,
P. Csatorday (MIT); D.  Lamb (U. Chicago); and J.G. Jernigan (UCB), on 
behalf of a Chandra GRB ToO Team,

write:

On 15 September 2004, the Chandra Observatory targeted the field of 
GRB040912, an X-ray flash localized by the HETE satellite (=H3557; 
Butler et al, GCN 2701). The 20 ksec observation spanned the 
interval 21:57 UT on 15 September to 3:48 UT on 16 September, 3.32 - 3.57
days after the burst. The WXM error circle from Butler et al. was completely 
contained within the field-of-view of the Chandra ACIS-I array.

Within the WXM error region, we detect 22 sources with more than 6
source counts in the 0.5-8 keV band:

 #      Chandra Name           RA           DEC         Cts   HR
 1 CXOU J235631.0-005946    23 56 30.96  -0  59 46.1    55   -0.5
 2 CXOU J235700.0-010009    23 56 59.96  -1   0  9.7    40   -0.3
 3 CXOU J235712.2-005942    23 57 12.17  -0  59 42.1    33   -0.3
 4 CXOU J235642.9-005520    23 56 42.91  -0  55 20.4    32   -0.7
 5 CXOU J235645.7-005655    23 56 46.71  -0  56 54.9    32   -0.3
 6 CXOU J235707.6-005713    23 57  7.57  -0  57 12.6    31    0.8
 7 CXOU J235716.4-010109    23 57 16.37  -1   1  8.7    27   -0.2
 8 CXOU J235639.1-005556    23 56 39.10  -0  55 55.8    20    0.9
 9 CXOU J235651.2-005513    23 56 51.17  -0  55 12.5    17   -0.3
10 CXOU J235636.7-005431    23 56 36.74  -0  54 31.2    15   -0.6
11 CXOU J235711.1-005637    23 57 11.12  -0  56 37.1    12   -0.2
12 CXOU J235637.3-010160    23 56 37.26  -1   1 59.9    12   -0.6
13 CXOU J235656.4-005839    23 56 56.42  -0  58 39.2    11   -0.1
14 CXOU J235700.1-005713    23 57  0.09  -0  57 12.6    11   -1.0
15 CXOU J235659.8-005903    23 56 59.83  -0  59  2.8    10   -0.6
16 CXOU J235649.1-010344    23 56 49.07  -1   3 44.2     9    0.4
17 CXOU J235700.4-010018    23 57  0.36  -1   0 17.6     9   -0.7
18 CXOU J235646.4_005621    23 56 46.45  -0  56 21.4     8    1.1
19 CXOU J235647.0-010045    23 56 46.97  -1   0 45.1     8    0.0
20 CXOU J235648.8-010319    23 56 48.81  -1   3 18.6     8   -1.0
21 CXOU J235704.0-005859    23 57  4.03  -0  58 58.8     8   -0.2
22 CXOU J235707.2-010420    23 57  7.18  -1   4 19.6     7    0.4

We estimate a position uncertainty of 1.0" for the Chandra sources. 
Astrometry was performed using five stars from the USNO-A2 catalog.
The column labeled HR in the table above refers to the hardness
ratio ( Cts_2-8keV - Cts_0.5-2keV )/ Cts_0.5-8 keV.  This quantity is
typically in the range -0.5 to -0.1 for GRBs at high Galactic latitude
and attenuated by the Galactic absorption only.

An image of the Chandra data, with the detected sources overlaid, can
be found at http://space.mit.edu/HETE/Bursts/GRB040912.

We gratefully acknowledge the timely assistance of the observatory staff 
at the Chandra Science Center in arranging for the acquisition and 
preliminary processing of these data.

This message may be cited.
Looking for U.S. government information and services? Visit USA.gov