GRB160821_203430_SWIFT at TAROT Calern observatory

TAROT Calern observatory log of images

AL_20160821_210653846_000000_30901701     6 stars filter C [ 1758.8s -  1938.8s] expo=180s elev=10.4deg humid= 89% sunelev=-24.7deg (moon at 129.0deg phase=0.74 elev= +7.0 )
AL_20160821_211006237_000000_30901701     5 stars filter C [ 1951.2s -  2131.2s] expo=180s elev=10.0deg humid= 88% sunelev=-25.1deg (moon at 129.0deg phase=0.74 elev= +8.0 )
AL_20160821_211319033_000000_30901701     4 stars filter R [ 2144.0s -  2324.0s] expo=180s elev= 9.6deg humid= 87% sunelev=-25.5deg (moon at 129.0deg phase=0.74 elev= +8.0 )
AL_20160821_211636756_000000_30901801     0 star  filter C [ 2341.8s -  2521.8s] expo=180s elev= 9.3deg humid= 87% sunelev=-25.9deg (moon at 129.0deg phase=0.74 elev= +9.0 )
AL_20160821_211949365_000000_30901801     5 stars filter C [ 2534.4s -  2714.4s] expo=180s elev= 8.9deg humid= 87% sunelev=-26.2deg (moon at 129.0deg phase=0.74 elev= +9.0 )
AL_20160821_212301959_000000_30901801     0 star  filter R [ 2727.0s -  2907.0s] expo=180s elev= 8.6deg humid= 87% sunelev=-26.6deg (moon at 129.0deg phase=0.74 elev=+10.0 )
AL_20160821_212619665_000000_30901901     0 star  filter C [ 2924.7s -  3104.7s] expo=180s elev= 8.2deg humid= 87% sunelev=-26.9deg (moon at 129.0deg phase=0.74 elev=+11.0 )
AL_20160821_212932509_000000_30901901     5 stars filter C [ 3117.5s -  3297.5s] expo=180s elev= 7.9deg humid= 86% sunelev=-27.3deg (moon at 129.0deg phase=0.74 elev=+11.0 )
AL_20160821_213244884_000000_30901901     3 stars filter R [ 3309.9s -  3489.9s] expo=180s elev= 7.5deg humid= 87% sunelev=-27.6deg (moon at 129.0deg phase=0.74 elev=+12.0 )
AL_20160821_213603988_000000_30902001     3 stars filter C [ 3509.0s -  3689.0s] expo=180s elev= 7.2deg humid= 87% sunelev=-27.9deg (moon at 129.0deg phase=0.74 elev=+12.0 )
AL_20160821_213916363_000000_30902001     3 stars filter C [ 3701.3s -  3881.3s] expo=180s elev= 6.9deg humid= 87% sunelev=-28.3deg (moon at 129.0deg phase=0.74 elev=+13.0 )
AL_20160821_214228754_000000_30902001     2 stars filter R [ 3893.7s -  4073.7s] expo=180s elev= 6.6deg humid= 87% sunelev=-28.6deg (moon at 129.0deg phase=0.74 elev=+13.0 )
AL_20160821_214547837_000000_30902101     2 stars filter C [ 4092.8s -  4272.8s] expo=180s elev= 6.2deg humid= 87% sunelev=-28.9deg (moon at 129.0deg phase=0.74 elev=+14.0 )
AL_20160821_214900228_000000_30902101     2 stars filter C [ 4285.2s -  4465.2s] expo=180s elev= 5.9deg humid= 87% sunelev=-29.2deg (moon at 129.0deg phase=0.74 elev=+15.0 )
AL_20160821_215213275_000000_30902101     3 stars filter R [ 4478.3s -  4658.3s] expo=180s elev= 5.6deg humid= 88% sunelev=-29.5deg (moon at 129.0deg phase=0.74 elev=+15.0 )
AL_20160821_215531248_000000_30902201     4 stars filter C [ 4676.2s -  4856.2s] expo=180s elev= 5.3deg humid= 89% sunelev=-29.8deg (moon at 129.0deg phase=0.74 elev=+16.0 )
AL_20160821_215844560_000000_30902201     3 stars filter C [ 4869.5s -  5049.5s] expo=180s elev= 5.0deg humid= 88% sunelev=-30.1deg (moon at 129.0deg phase=0.74 elev=+16.0 )
AL_20160821_220157607_000000_30902201     2 stars filter R [ 5062.6s -  5242.6s] expo=180s elev= 4.7deg humid= 88% sunelev=-30.3deg (moon at 129.0deg phase=0.74 elev=+17.0 )
Informations from GCN notice:
This is a GRB
Date of the alert : 2457622.35729 2016-08-21T20:34:29.856
Decoded useful notice informations.
RA(J2000.0) : 171.2475 11h24m59s3
DEC(J2000.0) : 42.3431 +42d20m35s15
Error radius : 3.0 arcmin

Other pages about TAROT Calern observatory observations

Sum of images.
Differential photometry.

Galactic coordinates

Galactic coordinates : lon=166.506520127 lat=66.7370313707
NASA/IPAC-Extragalactic-Database tool for calculate an extinction

Extinction from Schlegel et al. (1998, ApJ 500, 525): E(B-V)=0.024
Assuming Rv=3.1: Av=0.080 Ar=0.064 Ai=0.047 Extinction map E(B-V) from Schlegel:

Field of View is about 194 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 160821: 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 160821 detected by SWIFT
(trigger 709351) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 29.31min after the GRB trigger.
The elevation of the field decreased from
10 degrees above horizon and weather conditions
were XXX.

---- NO
The date of trigger : t0 = 2016-08-21T20:34:29.856

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+1758.8s to t0+1938.8s : R > 15.1

The second image is 180.0s exposure in tracking mode:
t0+1951.2s to t0+2131.2s : R > 16.2

We co-added a series of exposures:
t0+1951.2s to t0+3104.7s : 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 29.31min 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=166.5065 lat=+66.7370
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.