J/A+A/683/A55 GRB150309A Ks and g bands images (Castro-Tirado+, 2024)
Revealing the characteristics of the dark GRB 150309A:
Dust extinguished or high-z?
Castro-Tirado A.J., Gupta R., Pandey S.B., Nicuesa Guelbenzu A.,
Eikenberry S., Ackley K., Gerarts A., Valeev A.F., Jeong S., Park I.H.,
Oates S.R., Zhang B.-B., Sanchez-Ramirez R., Martin-Carrillo A., Tello J.C.,
Jelinek M., Hu Y.-D., Cunniffe R., Sokolov V.V., Guziy S., Ferrero P.,
Caballero-Garcia M.D., Ror A.K., Aryan A., Castro Tirado M.A.,
Fernandez-Garcia E., Gritsevich M., Olivares I., Perez-Garcia I.,
Castro Ceron J.M., Cepa J.
<Astron. Astrophys. 683, A55 (2024)>
=2024A&A...683A..55C 2024A&A...683A..55C (SIMBAD/NED BibCode)
ADC_Keywords: GRB ; Photometry, infrared ; Optical
Keywords: techniques: photometric - gamma-ray burst: general -
gamma-ray burst: individual: GRB 150309A
Abstract:
Dark Gamma-Ray Bursts (GRBs) constitute a significant fraction of the
GRB population. In this paper, we present the multiwavelength
analysis (both prompt emission and afterglow) of an intense
(3.98x10-5erg/cm2 using Fermi-Gamma-Ray Burst Monitor)
two-episodic GRB 150309A observed early on to ∼114 days post-burst.
Despite the strong gamma-ray emission, no optical afterglow was
detected for this burst. However, we discovered near-infrared (NIR)
afterglow (KS-band), ∼5.2 hours post burst, with the CIRCE instrument
mounted at the 10.4m Gran Telescopio Canarias (hereafter GTC).
We aim to examine characteristics of GRB 150309A as a dark burst and
to constrain other properties using multiwavelength observations.
We used Fermi observations of GRB 150309A to understand the prompt
emission mechanisms and jet composition. We performed the early
optical observations using the BOOTES robotic telescope and late-time
afterglow observations using the GTC. A potential faint host galaxy is
also detected at optical wavelength using the GTC.We modelled the
potential host galaxy of GRB 150309A in order to explore the
environment of the burst.
The time-resolved spectral analysis of Fermi data indicates a hybrid
jet composition consisting of a matter-dominated fireball and
magnetic-dominated Poynting flux. GTC observations of the afterglow
revealed that the counterpart of GRB 150309A was very red, with
H-Ks>2.1mag (95% confidence). The red counterpart was not discovered
in any bluer filters of Swift UVOT/BOOTES, indicative of high redshift
origin. This possibility was discarded based on multiple arguments,
such as spectral analysis of X-ray afterglow constrain z < 4.15 and a
moderate redshift value obtained using spectral energy distribution
(SED) modelling of the potential galaxy. The broadband (X-ray to NIR
bands) afterglow SED implies a very dusty host galaxy with deeply
embedded GRB (suggesting AV≳35mag).
The environment of GRB 150309A demands a high extinction towards the
line of sight, demanding dust obscuration is the most probable origin
of optical darkness and the very red afterglow of GRB 150309A. This
result makes GRB 150309A the highest extinguished GRB known to date.
Description:
GRB150309A early K-band plus late Sloan gri-band filters imaging.
Images gotten by the 10.4m GTC telescope.
Objects:
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RA (2000) DE Designation(s)
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18 28 24.80 +86 25 43.6 GRB 150309A = Fermi bn150309958
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 139 2 List of fits images
fits/* . 2 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 F5.3 arcsec/pix scale Scale of the image
26- 29 I4 --- Nx Number of pixels along X-axis
31- 34 I4 --- Ny Number of pixels along Y-axis
36- 58 A23 "datime" Obs.date Observation date
60- 63 I4 Kibyte size Size of FITS file
65- 91 A27 --- FileName Name of FITS file, in subdirectory fits
93-139 A47 --- Title Title of the FITS file
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Acknowledgements:
Alberto Javier Castro-Tirado, ajct(at)iaa.es
(End) Patricia Vannier [CDS] 30-Dec-2023