J/MNRAS/455/1027 Photometry of the afterglow of GRB 130831A (De Pasquale+, 2016)
The central engine of GRB 130831A and the energy breakdown of a relativistic
explosion.
De Pasquale M., Oates S.R., Racusin J.L., Kann D.A., Zhang B.,
Pozanenko A., Volnova A.A., Trotter A., Frank N., Cucchiara A., Troja E.,
Sbarufatti B., Butler N.R., Schulze S., Cano Z., Page M.J.,
Castro-Tirado A.J., Gorosabel J., Lien A., Fox O., Littlejohns O.,
Bloom J.S., Prochaska J.X., de Diego J.A., Gonzalez J., Richer M.G.,
Roman-Zuniga C., Watson A.M., Gehrels N., Moseley H., Kutyrev A., Zane S.,
Hoette V., Russell R.R., Rumyantsev V., Klunko E., Burkhonov O.,
Breeveld A.A., Reichart D.E., Haislip J.B.
<Mon. Not. R. Astron. Soc., 455, 1027-1042 (2016)>
=2016MNRAS.455.1027D 2016MNRAS.455.1027D (SIMBAD/NED BibCode)
ADC_Keywords: GRB ; Photometry, UBVRIJKLMNH ; Photometry, ultraviolet ;
Photometry, SDSS
Keywords: radiation mechanisms: non-thermal - shock waves -
gamma-ray burst: general - gamma-ray burst: individual: GRB 130831A -
stars: magnetars
Abstract:
Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe,
yet the nature and physical properties of their energy sources are far
from understood. Very important clues, however, can be inferred by
studying the afterglows of these events. We present optical and X-ray
observations of GRB 130831A obtained by Swift, Chandra, Skynet,
Reionization And Transients Infra-Red camera, Maidanak, International
Scientific Optical-Observation Network, Nordic Optical Telescope,
Liverpool Telescope and Gran Telescopio Canarias. This burst shows a steep
drop in the X-ray light curve at ∼105 s after the trigger, with a
power-law decay index of α∼6. Such a rare behaviour cannot be
explained by the standard forward shock (FS) model and indicates that
the emission, up to the fast decay at 105 s, must be of "internal
origin", produced by a dissipation process within an ultrarelativistic
outflow. We propose that the source of such an outflow, which must
produce the X-ray flux for ∼1 d in the cosmological rest frame, is a
newly born magnetar or black hole. After the drop, the faint X-ray
afterglow continues with a much shallower decay. The optical emission,
on the other hand, shows no break across the X-ray steep decrease, and
the late-time decays of both the X-ray and optical are consistent.
Using both the X-ray and optical data, we show that the emission after
∼105 s can be explained well by the FS model. We model our data to
derive the kinetic energy of the ejecta and thus measure the efficiency
of the central engine of a GRB with emission of internal origin visible
for a long time. Furthermore, we break down the energy budget of this
GRB into the prompt emission, the late internal dissipation, the kinetic
energy of the relativistic ejecta, and compare it with the energy of
the associated supernova, SN 2013 fu.
Description:
Swift/UVOT (Roming et al. 2005SSRv..120...95R 2005SSRv..120...95R) began observing the field
of GRB 130831A 114 s after the trigger (Hagen et al., GCN Circular 15139)
and started settled observations 191 s after the trigger, with a finding
chart exposure in the u band. The afterglow was detected in all seven
UVOT filters.
The Reionization And Transients InfraRed camera (RATIR) observed
GRB 130831A over a period of 7 h, beginning 15.8 h after the Swift trigger,
with follow-up observations on six nights over the next month. RATIR is
mounted on the 1.5-metre Harold L. Johnson telescope of the Observatorio
Astronomico Nacional on Sierra San Pedro Martir in Baja California (Mexico).
Skynet (Reichart et al. 2005NCimC..28..767R 2005NCimC..28..767R) obtained images of the
field of GRB 130831A on 2013 August 31 with four 17 arcsec telescopes
of the Panchromatic Robotic Optical Monitoring and Polarimetry Telescope
(PROMPT) array at Siding Spring Observatory, New South Wales, Australia.
The International Scientific Optical-Observation Network (ISON;
Molotov et al. 2008AdSpR..41.1022M 2008AdSpR..41.1022M; Pozanenko et al. 2013EAS....61..259P 2013EAS....61..259P)
started observing on 2013 August 31 at 13:14:32 ut, i.e. ∼10 min after
the trigger, with the 0.65-m telescope SANTEL-650 (Volnova et al.
2013GCN.15185....1V 2013GCN.15185....1V) of ISON-Ussuriysk observatory. The 50-cm telescope
VT-50 of ISON-Ussuriysk observatory started to observe at 13:26:10 ut,
22 min after the trigger, taking 384 unfiltered images with exposures
of 30 s in two epochs with a gap of about 1.8 h (Volnova et al.
2013GCN.15185....1V 2013GCN.15185....1V). Starting at 19:12:30 ut during the first day, the
40-cm SANkovich-TELescope (SANTEL) -400AN of ISON-Kislovodsk observatory
took 34 frames with exposures between 60 and 120 s (Volnova et al.
2013GCN.15188....1V 2013GCN.15188....1V).
Objects:
-------------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------------
23 54 29.92 +29 25 47.1 GRB 130831A = GRB 130831A
-------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 71 571 Photometry of the afterglow of GRB 130831A
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See also:
J/ApJ/686/1209 : Optical properties of GRB afterglows (Melandri+, 2008)
J/ApJ/690/163 : The first Swift UV-Opt GRB afterglow catalog (Roming+, 2009)
J/ApJ/693/1484 : Early optical afterglow catalog (Cenko+, 2009)
J/ApJ/701/824 : Afterglows of short and long-duration GRBs (Nysewander+, 2009)
J/ApJ/702/489 : ROTSE observations of gamma-ray burst afterglows
(Rykoff+, 2009)
J/ApJ/720/1513 : The afterglows of Swift-era GRBs. I. (Kann+, 2010)
J/ApJ/746/156 : Radio afterglow observations of GRBs (Chandra+, 2012)
J/A+A/568/A19 : Photometry of 3 γ-ray burst supernovae (Cano+, 2014)
J/ApJ/826/45 : GRB X-ray afterglows light curves analysis (Racusin+, 2016)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 I8 s t-t0 [120/13329792] Time since burst (t-t0)
10- 15 I6 s Texp [10/139477] Exposure time (1)
17 A1 --- l_mag [>] Limit flag on mag
18- 23 F6.3 mag mag [13.45/23.83] Magnitude in Filter (2)
25- 29 F5.3 mag E_mag [0.014/5.42]? Upper limit uncertainty in mag
31- 35 F5.3 mag e_mag [0.014/0.795]? Lower limit uncertainty in mag
37- 40 A4 --- Filter Filter used
42- 69 A28 --- Tel Telescope used
71 A1 --- Note [1] Note on photometric data (3)
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Note (1): Late exposure times of UVOT data actually show the interval between
the beginning and the end of observations.
Note (2): All magnitudes are in the Vega system.
Note (3): Note as follows:
1 = Data in common with Cano et al. 2014, J/A+A/568/A19.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 22-Aug-2018