J/MNRAS/426/2 GRB 091018 Optical/NIR photometry (Wiersema+, 2012)
Detailed optical and near-infrared polarimetry, spectroscopy and broad-band
photometry of the afterglow of GRB 091018: polarization evolution.
Wiersema K., Curran P.A., Kruhler T., Melandri A., Rol E., Starling R.L.C.,
Tanvir N.R., Van Der Horst A.J., Covino S., Fynbo J.P.U., Goldoni P.,
Gorosabel J., Hjorth J., Klose S., Mundell C.G., O'Brien P.T., Palazzi E.,
Wijers R.A.M.J., D'Elia V., Evans P.A., Filgas R., Gomboc A., Greiner J.,
Guidorzi C., Kaper L., Kobayashi S., Kouveliotou C., Levan A.J., Rossi A.,
Rowlinson A., Steele I.A., De Ugarte Postigo A., Vergani S.D.
<Mon. Not. R. Astron. Soc., 426, 2-22 (2012)>
=2012MNRAS.426....2W 2012MNRAS.426....2W
ADC_Keywords: Gamma rays ; Photometry
Keywords: acceleration of particles - techniques: polarimetric -
gamma-ray burst: individual: GRB 091018
Abstract:
Follow-up observations of large numbers of gamma-ray burst (GRB)
afterglows, facilitated by the Swift satellite, have produced a large
sample of spectral energy distributions and light curves, from which
their basic micro- and macro-physical parameters can in principle be
derived. However, a number of phenomena have been observed that defy
explanation by simple versions of the standard fireball model, leading
to a variety of new models. Polarimetry can be a major independent
diagnostic of afterglow physics, probing the magnetic field properties
and internal structure of the GRB jets. In this paper we present the
first high-quality multi-night polarimetric light curve of a Swift GRB
afterglow, aimed at providing a well-calibrated data set of a typical
afterglow to serve as a benchmark system for modelling afterglow
polarization behaviour.
Description:
GRB 091018 triggered the Burst Alert Telescope (BAT) on board the
Swift satellite at 20:48:19 ut on 2009 October 18 (trigger 373172;
Stamatikos et al., 2009GCN.10034....1S 2009GCN.10034....1S).
We acquired imaging polarimetry using the Focal Reducer and low
dispersion Spectrograph (FORS2) mounted on Unit Telescope 1 (Antu) of
the VLT, using the FORS2 Rspecial filter.
Objects:
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RA (2000) DE Designation(s)
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02 08 46 -57 33.0 GRB 091018 = GRB 091018
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 52 385 Log of our photometry
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Inst Instrument
13- 21 A9 --- Filt Filter (1)
22 A1 --- n_Filt [a] a: calibrated on to Sloan r using GROND
24- 32 F9.6 d Time Time since burst (d)
33- 41 F9.2 s t.exp Exposure time (s)
42 A1 --- l_mag Limit flag on mag
43- 47 F5.2 mag mag Magnitude in Filter, AB system, not corrected
for the Galactic foreground extinction
49- 52 F4.2 mag e_mag ? rms uncertainty on mag
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Note (1): Rsp for Rspecial
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Apr-2013