GRB180204_023617_SWIFT at TAROT Calern observatory

TAROT Calern observatory log of images

AL_20180204_042803244_000001_07863101     3 stars filter C [ 6521.4s -  6701.4s] expo=180s elev= 1.6deg humid= 78% sunelev=-25.6deg (moon at 133.0deg phase=0.73 elev=+43.0 )
AL_20180204_043113807_000001_07863101     3 stars filter C [ 6711.9s -  6891.9s] expo=180s elev= 2.0deg humid= 77% sunelev=-25.0deg (moon at 133.0deg phase=0.73 elev=+42.0 )
AL_20180204_043424073_000001_07863101     0 star  filter C [ 6902.2s -  7082.2s] expo=180s elev= 2.4deg humid= 77% sunelev=-24.5deg (moon at 133.0deg phase=0.73 elev=+42.0 )
AL_20180204_043745464_000003_77949501     5 stars filter C [ 7103.6s -  7283.6s] expo=180s elev= 2.8deg humid= 77% sunelev=-23.8deg (moon at 133.0deg phase=0.73 elev=+42.0 )
AL_20180204_044056930_000003_77949501     6 stars filter C [ 7295.1s -  7475.1s] expo=180s elev= 3.2deg humid= 80% sunelev=-23.3deg (moon at 133.0deg phase=0.73 elev=+41.0 )
AL_20180204_044406743_000003_77949501     7 stars filter C [ 7484.9s -  7664.9s] expo=180s elev= 3.7deg humid= 78% sunelev=-22.7deg (moon at 133.0deg phase=0.73 elev=+41.0 )
AL_20180204_044728415_000003_77949601     6 stars filter C [ 7686.5s -  7866.5s] expo=180s elev= 4.1deg humid= 79% sunelev=-22.1deg (moon at 133.0deg phase=0.73 elev=+41.0 )
AL_20180204_045039184_000003_77949601     0 star  filter C [ 7877.3s -  8057.3s] expo=180s elev= 4.5deg humid= 81% sunelev=-21.5deg (moon at 133.0deg phase=0.73 elev=+40.0 )
AL_20180204_045712481_000001_07863401     3 stars filter C [ 8270.6s -  8450.6s] expo=180s elev= 5.4deg humid= 81% sunelev=-20.3deg (moon at 133.0deg phase=0.73 elev=+39.0 )
AL_20180204_050023473_000001_07863401     3 stars filter C [ 8461.6s -  8641.6s] expo=180s elev= 5.9deg humid= 77% sunelev=-19.8deg (moon at 133.0deg phase=0.73 elev=+39.0 )
AL_20180204_050334942_000001_07863401     3 stars filter C [ 8653.0s -  8833.0s] expo=180s elev= 6.3deg humid= 79% sunelev=-19.2deg (moon at 133.0deg phase=0.73 elev=+39.0 )
AL_20180204_050656785_000003_77949801     5 stars filter C [ 8854.9s -  9034.9s] expo=180s elev= 6.8deg humid= 79% sunelev=-18.6deg (moon at 133.0deg phase=0.73 elev=+38.0 )
AL_20180204_051007082_000003_77949801    10 stars filter C [ 9045.2s -  9225.2s] expo=180s elev= 7.2deg humid= 79% sunelev=-18.0deg (moon at 133.0deg phase=0.73 elev=+38.0 )
AL_20180204_051317360_000003_77949801    12 stars filter C [ 9235.5s -  9415.5s] expo=180s elev= 7.7deg humid= 79% sunelev=-17.4deg (moon at 133.0deg phase=0.73 elev=+37.0 )
AL_20180204_052110119_000003_77950001     6 stars filter C [ 9708.3s -  9888.3s] expo=180s elev= 8.8deg humid= 78% sunelev=-16.0deg (moon at 133.0deg phase=0.73 elev=+36.0 )
AL_20180204_052420431_000003_77950001     4 stars filter C [ 9898.5s - 10078.5s] expo=180s elev= 9.3deg humid= 77% sunelev=-15.5deg (moon at 133.0deg phase=0.73 elev=+36.0 )
AL_20180204_052730462_000003_77950001     8 stars filter C [10088.6s - 10268.6s] expo=180s elev= 9.8deg humid= 78% sunelev=-14.9deg (moon at 133.0deg phase=0.73 elev=+35.0 )
AL_20180204_053059761_000003_77950101    12 stars filter C [10297.9s - 10477.9s] expo=180s elev=10.3deg humid= 76% sunelev=-14.3deg (moon at 133.0deg phase=0.73 elev=+35.0 )
AL_20180204_053410058_000003_77950101     8 stars filter C [10488.2s - 10668.2s] expo=180s elev=10.8deg humid= 77% sunelev=-13.7deg (moon at 133.0deg phase=0.73 elev=+35.0 )
AL_20180204_053720823_000003_77950101     8 stars filter C [10678.9s - 10858.9s] expo=180s elev=11.3deg humid= 78% sunelev=-13.1deg (moon at 133.0deg phase=0.73 elev=+34.0 )
AL_20180204_054042230_000001_07863901     0 star  filter C [10880.4s - 11060.4s] expo=180s elev=11.8deg humid= 80% sunelev=-12.5deg (moon at 133.0deg phase=0.73 elev=+34.0 )
AL_20180204_054352555_000001_07863901     0 star  filter C [11070.6s - 11250.6s] expo=180s elev=12.3deg humid= 80% sunelev=-12.0deg (moon at 133.0deg phase=0.73 elev=+33.0 )
AL_20180204_054702789_000001_07863901     0 star  filter C [11260.9s - 11440.9s] expo=180s elev=12.7deg humid= 80% sunelev=-11.4deg (moon at 133.0deg phase=0.73 elev=+33.0 )
AL_20180204_055024023_000001_07864001     0 star  filter C [11462.1s - 11642.1s] expo=180s elev=13.3deg humid= 79% sunelev=-10.8deg (moon at 133.0deg phase=0.73 elev=+32.0 )
AL_20180204_055334265_000001_07864001     0 star  filter C [11652.4s - 11832.4s] expo=180s elev=13.8deg humid= 79% sunelev=-10.3deg (moon at 133.0deg phase=0.73 elev=+32.0 )
AL_20180204_055644578_000001_07864001     0 star  filter C [11842.7s - 12022.7s] expo=180s elev=14.3deg humid= 91% sunelev=-9.7deg (moon at 133.0deg phase=0.73 elev=+31.0 )
AL_20180204_060005547_000003_77950401     0 star  filter C [12043.6s - 12223.6s] expo=180s elev=14.8deg humid= 91% sunelev=-9.1deg (moon at 133.0deg phase=0.73 elev=+31.0 )
AL_20180204_060625881_000003_77950401     0 star  filter C [12424.0s - 12604.0s] expo=180s elev=15.8deg humid= 78% sunelev=-8.0deg (moon at 133.0deg phase=0.73 elev=+30.0 )
Informations from GCN notice:
This is a GRB
Date of the alert : 2458153.6085265 2018-02-04T02:36:16.690
Decoded useful notice informations.
RA(J2000.0) : 330.1177 22h00m28s2
DEC(J2000.0) : 30.8457 +30d50m44s52
Error radius : 3.0 arcmin

Other pages about TAROT Calern observatory observations

Sum of images.
Differential photometry.

Galactic coordinates

Galactic coordinates : lon=84.8582596452 lat=-19.1096927705
NASA/IPAC-Extragalactic-Database tool for calculate an extinction

Extinction from Schlegel et al. (1998, ApJ 500, 525): E(B-V)=0.136
Assuming Rv=3.1: Av=0.450 Ar=0.362 Ai=0.263 Extinction map E(B-V) from Schlegel:

Field of View is about 67 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 180204: TAROT Calern observatory optical observations
Klotz A., Noysena.K., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Eymar, L. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 180204 detected by SWIFT
(trigger 808483) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 1.81h after the GRB trigger.
The elevation of the field increased from
1 degrees above horizon and weather conditions
were XXX.

---- NO
The date of trigger : t0 = 2018-02-04T02:36:16.690

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+6521.4s to t0+6701.4s : R > 15.1

The second image is 180.0s exposure in tracking mode:
t0+6711.9s to t0+6891.9s : R > 16.2

We co-added a series of exposures:
t0+6711.9s to t0+7866.5s : 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 1.81h 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= 84.8583 lat=-19.1097
and the galactic extinction in R band is 0.4 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.