GCN Circular 2724

J. Gorosabel (IAC-CSIC  Granada), J. Cepa (IAC 
Tenerife),  A. de Ugarte Postigo (IAA-CSIC), 
D. Mart�nez-Delgado (MPIfA Heidelberg),  V. Casanova, 
S. Guziy, M. Jel�nek (IAA-CSIC, Granada), J. M. 
Castro Cer�n (San Fernando), H. Castaneda (IAC 
Tenerife), D. Zucker, E. F. Bell (AIP Potsdam) 
and A. J. Castro-Tirado (IAA-CSIC)

report:

"We have acquired optical images covering the 
entire error box of the XRF 040912 detected by 
HETE-2 (Ricker et al. GCN Circ. 2701
Not found
 
 
) starting
on 12 Sep 21:27 UT (i.e. 7.25 hr after the event). 
The  observations were performed with the 4.2m 
WHT (+PFC) at La Palma (16'x 16' FOV).

The observing log follows:

 -----------------------------------
 Date 2004 UT    Exp.Time (s)  Filter  
 -----------------------------------
 12 Sep 21:27:56      1455      B
 12 Sep 21:53:45       900      V
 13 Sep 04:26:41       900      V
 13 Sep 21:07:58      1200      V 
 16 Sep 01:49:11       300      I
 16 Sep 01:58:17       300      I
 16 Sep 02:05:06       300      I
 16 Sep 02:11:17       300      I
 16 Sep 02:18:16       300      I
 16 Sep 02:31:05       180      V
 16 Sep 02:35:14      1200      V
 ----------------------------------

Additional images (I-band, 720-s) were also 
taken at the 1.5m telescope at IAA Sierra 
Nevada Observatory on 13 Sep (03:00 UT). 

Internal comparison between the three V-band 
frames did not reveal any optical variable 
source in the entire HETE-2 error box. For 
the 22 X-rays sources detected by the Chandra 
X-ray Observatory (Butler et al., GCN Circ 
2716
Not found
 
 
) we detect the following optical 
counterparts in the co-added V-band image 
(3 sigma limiting magnitude = 25.1):

 -------------------------------------
 CXO      V-band     Distance to
 source   magnitude  X-ray position (")
 -------------------------------------
   #1       21.6        2.0 
   #2       24.0        2.0 
   #3       21.1        2.0 
   #4       24.0        2.0 
   #5       21.9        1.4  
   #6       21.0        1.7 
   #7       22.9        1.7 
   #8       23.9        1.4 
   #9       23.9        1.8 
   #10      21.1        1.6 
   #11      23.0        1.4 
   #12      24.2        1.9 
   #13      23.6        0.5 
   #14*     23.9        0.9
            22.7        1.8 
   #15      23.9        2.1 
   #16**   >25.1         - 
   #17      24.5        2.0 
   #18      23.3        0.1 
   #19     >25.1         - 
   #20     >25.1         -        
   #21     >25.1         - 
   #22     >25.1         - 
 --------------------------------------
 * Two possible counterparts
 * V = 22.1 optical source at 3".5 
 --------------------------------------

Optical magnitudes are based on the calibration 
provided by A. Henden (GCN Circ. 2720
Not found
 
 
)."

This message can be quoted.

[GCN OPS NOTE (21sep04): The affiliation for
D. Martinez-Delgado from "AIP Potsdam" to
"MPIfA Heidelberg".]