GRB150621_192321_INTEGRAL at TAROT Calern observatory

TAROT Calern observatory log of images

AL_20150621_204411283_000003_46609801     0 star  filter C [ 4665.3s -  4845.3s] expo=180s elev=30.1deg humid= 89% sunelev=-12.1deg (moon at 131.0deg phase=0.34 elev=+15.0 )
AL_20150621_204722048_000003_46609801    21 stars filter C [ 4856.1s -  5036.1s] expo=180s elev=30.7deg humid= 89% sunelev=-12.5deg (moon at 131.0deg phase=0.34 elev=+15.0 )
AL_20150621_205032506_000003_46609801    13 stars filter R [ 5046.6s -  5226.6s] expo=180s elev=31.2deg humid= 88% sunelev=-12.8deg (moon at 131.0deg phase=0.34 elev=+14.0 )
AL_20150621_205352318_000003_46609901    42 stars filter C [ 5246.4s -  5426.4s] expo=180s elev=31.8deg humid= 87% sunelev=-13.2deg (moon at 131.0deg phase=0.34 elev=+14.0 )
AL_20150621_205702600_000003_46609901    86 stars filter C [ 5436.7s -  5616.7s] expo=180s elev=32.3deg humid= 87% sunelev=-13.5deg (moon at 131.0deg phase=0.34 elev=+13.0 )
AL_20150621_205825961_000003_46609901     0 star  filter R [ 5627.4s -  5807.4s] expo=180s elev=32.9deg humid= 85% sunelev=-13.9deg (moon at 131.0deg phase=0.34 elev=+13.0 )
AL_20150621_212353914_000003_46610201    85 stars filter C [ 7048.0s -  7228.0s] expo=180s elev=37.0deg humid= 84% sunelev=-16.3deg (moon at 131.0deg phase=0.34 elev= +8.0 )
AL_20150621_212704836_000003_46610201    80 stars filter C [ 7239.0s -  7419.0s] expo=180s elev=37.5deg humid= 85% sunelev=-16.6deg (moon at 131.0deg phase=0.34 elev= +8.0 )
AL_20150621_213015424_000003_46610201    81 stars filter R [ 7429.5s -  7609.5s] expo=180s elev=38.1deg humid= 86% sunelev=-16.9deg (moon at 131.0deg phase=0.34 elev= +7.0 )
Informations from GCN notice:
This is a GRB
Date of the alert : 2457195.30788 2015-06-21T19:23:20.832
Decoded useful notice informations.
RA(J2000.0) : 306.015304583 20h24m03s6
DEC(J2000.0) : 33.8462662385 +33d50m46s55
Error radius : 3.3 arcmin

Other pages about TAROT Calern observatory observations

Sum of images.
Differential photometry.

Galactic coordinates

Galactic coordinates : lon=73.1011946119 lat=-2.1028395111
NASA/IPAC-Extragalactic-Database tool for calculate an extinction

Extinction from Schlegel et al. (1998, ApJ 500, 525): E(B-V)=0.494
Assuming Rv=3.1: Av=1.637 Ar=1.320 Ai=0.958 Extinction map E(B-V) from Schlegel:

Field of View is about 56 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 150621: TAROT Calern observatory optical observations
Klotz A., Turpin D. (IRAP-CNRS-OMP),
Boer M., Gendre B., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA),
Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 150621 detected by INTEGRAL
(trigger 7093) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 1.30h after the GRB trigger.
The elevation of the field increased from
30 degrees above horizon and weather conditions
were XXX.

---- NO
The date of trigger : t0 = 2015-06-21T19:23:20.832

The first image is trailed with a duration of 180.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect any OT with a limiting magnitude of:
t0+4665.3s to t0+4845.3s : R > 15.1

The second image is 180.0s exposure in tracking mode:
t0+4856.1s to t0+5036.1s : R > 16.2

We co-added a series of exposures:
t0+4856.1s to t0+7228.0s : R > 17.7
---- YES
We detect a new fading source in the error box given by INTEGRAL
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 1.30h 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= 73.1012 lat= -2.1028
and the galactic extinction in R band is 1.3 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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