GRB120727_222446_SWIFT at TAROT Calern observatory

TAROT Calern observatory log of images

AL_20120727_222723692_000000_00000001     0 star  filter C [   92.3s -   152.3s] expo= 60s elev= 3.6deg humid= 39% sunelev=-25.1deg (moon at  59.0deg phase=0.61 elev= +7.0 )
AL_20120727_222809302_000000_00000001     0 star  filter C [  167.9s -   197.9s] expo= 30s elev= 3.5deg humid= 38% sunelev=-25.2deg (moon at  59.0deg phase=0.61 elev= +7.0 )
AL_20120727_222849864_000000_00000001     0 star  filter C [  208.5s -   238.5s] expo= 30s elev= 3.4deg humid= 38% sunelev=-25.2deg (moon at  59.0deg phase=0.61 elev= +6.0 )
AL_20120727_222930817_000000_00000001     0 star  filter C [  249.4s -   279.4s] expo= 30s elev= 3.3deg humid= 38% sunelev=-25.3deg (moon at  59.0deg phase=0.61 elev= +6.0 )
AL_20120727_223011692_000000_00000001     0 star  filter C [  290.4s -   320.4s] expo= 30s elev= 3.2deg humid= 37% sunelev=-25.3deg (moon at  59.0deg phase=0.61 elev= +6.0 )
AL_20120727_223052990_000000_00000001     0 star  filter C [  331.6s -   361.6s] expo= 30s elev= 3.0deg humid= 36% sunelev=-25.4deg (moon at  59.0deg phase=0.61 elev= +6.0 )
AL_20120727_223415153_000000_00000001     0 star  filter C [  473.8s -   563.8s] expo= 90s elev= 2.6deg humid= 36% sunelev=-25.5deg (moon at  59.0deg phase=0.61 elev= +6.0 )
AL_20120727_223737357_000000_00000001     0 star  filter C [  675.9s -   765.9s] expo= 90s elev= 2.1deg humid= 33% sunelev=-25.7deg (moon at  59.0deg phase=0.61 elev= +5.0 )
AL_20120727_223918513_000000_00000001     0 star  filter C [  777.1s -   867.1s] expo= 90s elev= 1.8deg humid= 33% sunelev=-25.8deg (moon at  59.0deg phase=0.61 elev= +5.0 )
AL_20120727_224059466_000000_00000001     0 star  filter R [  878.1s -   968.1s] expo= 90s elev= 1.6deg humid= 34% sunelev=-25.8deg (moon at  59.0deg phase=0.61 elev= +5.0 )
AL_20120727_224240503_000000_00000001     0 star  filter C [  979.1s -  1069.1s] expo= 90s elev= 1.3deg humid= 34% sunelev=-25.9deg (moon at  59.0deg phase=0.61 elev= +5.0 )
AL_20120727_224420754_000000_00000001     0 star  filter C [ 1079.4s -  1169.4s] expo= 90s elev= 1.1deg humid= 34% sunelev=-26.0deg (moon at  59.0deg phase=0.61 elev= +4.0 )
AL_20120727_224601519_000000_00000001     0 star  filter R [ 1180.1s -  1270.1s] expo= 90s elev= 0.8deg humid= 34% sunelev=-26.1deg (moon at  59.0deg phase=0.61 elev= +4.0 )
AL_20120727_224742895_000000_00000001     0 star  filter C [ 1281.5s -  1371.5s] expo= 90s elev= 0.6deg humid= 36% sunelev=-26.1deg (moon at  59.0deg phase=0.61 elev= +4.0 )
AL_20120727_224923864_000000_00000001     0 star  filter C [ 1382.5s -  1472.5s] expo= 90s elev= 0.3deg humid= 37% sunelev=-26.2deg (moon at  59.0deg phase=0.61 elev= +4.0 )
Informations from GCN notice:
This is a GRB
Date of the alert : 2456136.43387 2012-07-27T22:24:46.367
Decoded useful notice informations.
RA(J2000.0) : 186.5468 12h26m11s2
DEC(J2000.0) : 18.0664 +18d03m59s03
Error radius : 4.0 arcmin

Other pages about TAROT Calern observatory observations

Sum of images.
Differential photometry.

Galactic coordinates

Galactic coordinates : lon=268.914788 lat=79.231143
NASA/IPAC-Extragalactic-Database tool for calculate an extinction

Extinction from Schlegel et al. (1998, ApJ 500, 525): E(B-V)=0.026
Assuming Rv=3.1: Av=0.087 Ar=0.070 Ai=0.051 Extinction map E(B-V) from Schlegel:

Field of View is about 417 arcmin (north is NOT up !)

Bibliography (Last GCNC circulars and status of satellites)

GCN infos of this burst
GCN notice of this burst
Sloan Digital Sky Survey Observations of Gamma Ray Burst Fields
GCN info bursts
Gamma-ray burst real-time sky map
ROTSE last GRB images

Example of a GCNC email for this burst
GRB 120727: TAROT Calern observatory optical observations
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 120727 detected by SWIFT
(trigger 528925) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 92.3s after the GRB trigger
(18.0s after the notice). The elevation of the field decreased from
3 degrees above horizon and weather conditions
were XXX.

---- NO
The date of trigger : t0 = 2012-07-27T22:24:46.367

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect any OT with a limiting magnitude of:
t0+92.3s to t0+152.3s : R > 15.1

The second image is 30.0s exposure in tracking mode:
t0+167.9s to t0+197.9s : R > 16.2

We co-added a series of exposures:
t0+167.9s to t0+563.8s : R > 17.7
---- YES
We detect a new fading source in the error box given by SWIFT
We detected the candidate couterpart mentioned by XXX et al. (GCNC XXXX)
at the following position (+/- 3 arcsec):

RA(J2000.0) = XXh XXm XX.XXs
DEC(J2000.0) +XXd XX' XX.X"

OT was R~XX.X at 92.3s after GRB.

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon=268.9148 lat=+79.2311
and the galactic extinction in R band is 0.1 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.