J/A+A/572/A12 GRB 140506A spectra (Fynbo+, 2014)
The mysterious optical afterglow spectrum of GRB 140506A at z = 0.889.
Fynbo J.P.U., Kruhler T., Leighly K., Ledoux C., Vreeswijk P.M., Schulze S.,
Noterdaeme P., Watson D., Wijers R.A.M.J., Bolmer J., Cano Z.,
Christensen L., Covino S., D'Elia V., Flores H., Friis M., Goldoni P.,
Greiner J., Hammer F., Hjorth J., Jakobsson P., Japelj J., Kaper L.,
Klose S., Knust F., Leloudas G., Levan A., Malesani D., Milvang-Jensen B.,
Moller P., Nicuesa Guelbenzu A., Oates S., Pian E., Schady P., Sparre M.,
Tagliaferri G., Tanvir N., Thone C.C., de Ugarte Postigo A., Vergani S.,
Wiersema K., Xu D., Zafar T.
<Astron. Astrophys. 572, A12 (2014)>
=2014A&A...572A..12F 2014A&A...572A..12F
ADC_Keywords: Gamma rays ; Spectroscopy
Keywords: gamma-ray burst: individual: GRB140506A - ISM: abundances -
dust, extinction - ISM: molecules
Abstract:
Gamma-ray burst (GRB) afterglows probe sightlines to star-forming
regions in distant star-forming galaxies. Here we present a study of
the peculiar afterglow spectrum of the z=0.889 Swift GRB 140506A.
Our aim is to understand the origin of the very unusual properties of
the absorption along the line of sight.
We analyse spectroscopic observations obtained with the X-shooter
spectrograph mounted on the ESO/VLT at two epochs 8.8h and 33h after
the burst, and with imaging from the GROND instrument. We also present
imaging and spectroscopy of the host galaxy obtained with the Magellan
telescope.
Description:
On 2014 May 7, with a mid exposure time of 8.8h post burst, we
acquired a medium-resolution spectrum with the X-shooter spectrograph
mounted at the ESO/VLT, covering a range of 300-2300nm (Fynbo et al.,
2014, GRB, 16217, 1). The spectrum was taken under excellent
conditions with a photometric sky and a very good seeing of 0.54" in
the R band. The observation was carried out in two executions of a
4x600s observing block following an ABBA nodding pattern. The slit
was re-aligned with the parallactic angle between the two executions
of the observing block. The slit widths were 1.0", 0.9", and 0.9"
in the UVB, VIS, and NIR arms, respectively. The airmasses at the
start and end of the spectroscopic observation were 1.43 and 1.22. For
the given instrument setup, the nominal resolution is 5500, 8800, and
5100 in the UVB, VIS, and NIR. As the seeing was smaller than the slit
width, the actual resolution is higher than this. For the VIS, we
measure the resolution from the width of telluric absorption lines and
find it to be 24km/s (FWHM). For the UVB and NIR arms we find
∼40 and 42km/s. All wavelengths are in vacuum and are corrected
for the heliocentric velocity of 18.9km/s.
Objects:
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RA (2000) DE Designation(s)
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18 27 06.03 -55 33 08.8 GRB 140506A = GRB 140506A
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ep1nir.dat 42 21654 GRB140506A epoch 1 (ΔT=8.8h) NIR spectrum
ep1uvb.dat 42 6548 GRB140506A epoch 1 (ΔT=8.8h) UBV spectrum
ep1vis.dat 42 11196 GRB140506A epoch 1 (ΔT=8.8h) VIS spectrum
ep2nir.dat 42 21654 GRB140506A epoch 2 (ΔT=33h) NIR spectrum
ep2uvb.dat 42 6548 GRB140506A epoch 2 (ΔT=33h) UBV spectrum
ep2vis.dat 42 11196 GRB140506A epoch 2 (ΔT=33h) VIS spectrum
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Byte-by-byte Description of file: ep*.dat
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Bytes Format Units Label Explanations
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1- 12 F12.6 0.1nm lambda [3200/23000] Observed wavelength
17- 27 E11.5 cW/m2/nm Flux Flux density (erg/cm2/s/Å)
33- 42 E10.5 cW/m2/nm e_Flux rms uncertainty on Flux (erg/cm2/s/Å)
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Acknowledgements:
Johan Fynbo, jfynbo(at)dark-cosmology.dk
(End) Patricia Vannier [CDS] 19-Nov-2014