GRB170903_124907_SWIFT at TAROT Calern observatory

TAROT Calern observatory log of images

AL_20170903_192612653_000000_83090001    10 stars filter C [23640.3s - 23820.3s] expo=180s elev=67.8deg humid=  0% sunelev=-14.4deg (moon at  76.0deg phase=0.84 elev=+22.0 )
AL_20170903_192923425_000000_83090001    10 stars filter C [23831.1s - 24011.1s] expo=180s elev=67.3deg humid=  0% sunelev=-15.0deg (moon at  76.0deg phase=0.84 elev=+22.0 )
AL_20170903_193233707_000000_83090001    10 stars filter C [24021.4s - 24201.4s] expo=180s elev=66.7deg humid=  0% sunelev=-15.5deg (moon at  76.0deg phase=0.84 elev=+22.0 )
AL_20170903_195041950_000000_83090101     8 stars filter C [25109.6s - 25289.6s] expo=180s elev=63.5deg humid=  0% sunelev=-18.4deg (moon at  76.0deg phase=0.84 elev=+24.0 )
AL_20170903_195354122_000000_83090101    10 stars filter C [25301.8s - 25481.8s] expo=180s elev=62.9deg humid=  0% sunelev=-18.9deg (moon at  76.0deg phase=0.84 elev=+24.0 )
AL_20170903_195705232_000000_83090101    11 stars filter C [25493.0s - 25673.0s] expo=180s elev=62.3deg humid=  0% sunelev=-19.3deg (moon at  76.0deg phase=0.84 elev=+24.0 )
AL_20170903_201511926_000000_83090201    11 stars filter C [26579.6s - 26759.6s] expo=180s elev=59.1deg humid=  0% sunelev=-22.1deg (moon at  77.0deg phase=0.84 elev=+26.0 )
AL_20170903_201822566_000000_83090201    12 stars filter C [26770.3s - 26950.3s] expo=180s elev=58.5deg humid=  0% sunelev=-22.5deg (moon at  77.0deg phase=0.84 elev=+26.0 )
AL_20170903_202132899_000000_83090201    10 stars filter C [26960.6s - 27140.6s] expo=180s elev=57.9deg humid=  0% sunelev=-23.0deg (moon at  77.0deg phase=0.84 elev=+26.0 )
Informations from GCN notice:
This is a GRB
Date of the alert : 2458000.03411 2017-09-03T12:49:07.104
Decoded useful notice informations.
RA(J2000.0) : 254.5251 16h58m06s0
DEC(J2000.0) : 34.9793 +34d58m45s48
Error radius : 3.2 arcsec
Error box : x=51:53 y=58:60 (pixels)

Other pages about TAROT Calern observatory observations

Sum of images.
Differential photometry.

Galactic coordinates

Galactic coordinates : lon=57.7120322901 lat=37.4207002403
NASA/IPAC-Extragalactic-Database tool for calculate an extinction

Extinction from Schlegel et al. (1998, ApJ 500, 525): E(B-V)=0.016
Assuming Rv=3.1: Av=0.053 Ar=0.043 Ai=0.031 Extinction map E(B-V) from Schlegel:

Field of View is about 88 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 170903: TAROT Calern observatory optical observations
Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 170903 detected by SWIFT
(trigger 770528) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 6.57h after the GRB trigger.
The elevation of the field decreased from
67 degrees above horizon and weather conditions
were XXX.

---- NO
The date of trigger : t0 = 2017-09-03T12:49:07.104

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+23640.3s to t0+23820.3s : R > 15.1

The second image is 180.0s exposure in tracking mode:
t0+23831.1s to t0+24011.1s : R > 16.2

We co-added a series of exposures:
t0+23831.1s to t0+26759.6s : 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 6.57h 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= 57.7120 lat=+37.4207
and the galactic extinction in R band is 0.0 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.