GRB041211: Search for an optical transient
Observation: 11 Dec 2004
Creation: 25 Dec 2004
10 hours after the burst, no optical counterpart down to mag 17.8.
The gamma ray burst GRB041211 was discovered by the HETE satellite, with a circular error box of 80" radius. It is a classical hard GRB with a duration >100s and a 30-400 keV fluence of 1.0 x 10-5 ergs cm-2 [Dezalay et al (GCN 2839)].
I observed the gamma ray burst field 10 h 18 mn after the event with a 203 mm SC telescope fitted with a Clear filter and a SBIG ST7E camera. The galactic coordinates are around b=7.5° l=195° and there was no Moon. I obtained 10 one-minute exposure images that I stacked.
I did not blink the resulting image against e.g. the DSS. Instead, I used the AstroMB software to scan the image and to match the detected sources against catalogs:
Therefore no optical counterpart are detected.
The image is here.
To evaluate the sensitivity of the search, the sequence from Henden (GCN 2844) is used. The limit magnitude is estimated as 17.8. (This is not very precise because the observation is done with no filter).
No other observer found an optical counterpart.