J/ApJ/872/118 Optical obs. of GRB 180205A with COATLI (Becerra+, 2019)
Late central-engine activity in GRB 180205A.
Becerra R.L., Watson A.M., Fraija N., Butler N.R., Lee W.H., Troja E.,
Roman-Zuniga C.G., Kutyrev A.S., Alvarez Nunez L.C., Angeles F., Chapa O.,
Cuevas S., Farah A.S., Fuentes-Fernandez J., Figueroa L., Langarica R.,
Quiros F., Ruiz-Diaz-Soto J., Tejada C.G., Tinoco S.J.
<Astrophys. J., 872, 118 (2019)>
=2019ApJ...872..118B 2019ApJ...872..118B
ADC_Keywords: GRB; Photometry; Optical
Keywords: gamma-ray burst: individual (GRB 180205A)
Abstract:
We present optical photometry of the afterglow of the long GRB 180205A
with the COATLI telescope from 217s to about 5d after the Swift/BAT
trigger. We analyze this photometry in conjunction with the X-ray
light curve from Swift/XRT. The late-time light curves and spectra are
consistent with the standard forward-shock scenario. However, the
early-time optical and X-ray light curves show atypical behavior; the
optical light curve exhibits a flat plateau while the X-ray light
curve shows a flare. We explore several scenarios and conclude that
the most likely explanation for the early behavior is late activity of
the central engine.
Description:
The Fermi/GBM instrument triggered on GRB180205A at 2018 February 5
04:25:25.393 UTC (trigger 539497530/180205184) and observed several
pulses with a T90 duration of 15.4±1.4s.
The Swift/BAT instrument triggered on GRB180205A at T=2018 February 5
04:25:29.33 UTC (trigger 808625) and observed a multipeaked structure
from about T-7s to about T+11s. The Swift/XRT instrument started
observing the field at T+162s. The Swift/UVOT instrument started
observing the field at T+181s.
COATLI is a robotic 50cm telescope at the Observatorio Astronomico
Nacional on the Sierra de San Pedro Martir in Baja California, Mexico.
COATLI started to observe GRB 180205A at 04:29:06.3 UTC; our first
observation started at T+217s. All of our COATLI observations are 5s
exposures in the clear w filter (∼400-850nm with pivot wavelength at
630nm).
Objects:
-------------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------------
08 27 16.72 +11 32 31.6 GRB 180205A = GRB 180205A
-------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 38 188 COATLI observations of GRB 180205A
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See also:
B/eso : ESO Science Archive Catalog (ESO, 1991-2020)
J/AJ/133/1027 : Positions for 179 Swift X-ray afterglows (Butler+, 2007)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
J/ApJ/701/824 : Afterglows of GRBs (Nysewander+, 2009)
J/PASP/124/140 : UBVRI Hp BT and VT photonic responses (Bessell+, 2012)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/A+A/562/A29 : GRB 100814A GROND and UVOT light curves (Nardini+, 2014)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.1 s ti [217/424009] Exposure start time (1)
10- 17 F8.1 s tf [217.8/463199.5] Exposure end time (1)
19- 25 F7.1 s texp [0.8/29230] Total exposure time
27- 32 F6.3 mag wmag [15.5/21.5] COATLI AB magnitude w, not corrected
for Galactic extinction
34- 38 F5.3 mag e_wmag [0.017/0.2] 1σ total uncertainty in wmag (2)
--------------------------------------------------------------------------------
Note (1): Exposure start and end times are relative to the Swift/BAT trigger
time, T=2018 February 05 04:25:29.33 UTC.
Note (2): Total uncertainty in wmag includes both statistical and systematic
contributions.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Aug-2020