J/MNRAS/473/1512 AMI 15.7GHz GRB catalogue (Anderson+, 2018)
The Arcminute Microkelvin Imager catalogue of gamma-ray burst afterglows
at 15.7 GHz.
Anderson G.E., Staley T.D., van der Horst A.J., Fender R.P., Rowlinson A.,
Mooley K.P., Broderick J.W., Wijers R.A.M.J., Rumsey C., Titterington D.J.
<Mon. Not. R. Astron. Soc., 473, 1512-1536 (2018)>
=2018MNRAS.473.1512A 2018MNRAS.473.1512A (SIMBAD/NED BibCode)
ADC_Keywords: GRB ; Gamma rays ; Radio sources
Keywords: gamma-ray burst: general - radio continuum: transients
Abstract:
We present the Arcminute Microkelvin Imager (AMI) Large Array
catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central
frequency of 15.7GHz and is equipped with a fully automated
rapid-response mode, which enables the telescope to respond to
high-energy transients detected by Swift. On receiving a transient
alert, AMI can be on-target within 2-min, scheduling later start times
if the source is below the horizon. Further AMI observations are
manually scheduled for several days following the trigger. The AMI GRB
programme probes the early-time (<1d) radio properties of GRBs, and
has obtained some of the earliest radio detections (GRB 130427A at
0.36 and GRB 130907A at 0.51d post-burst). As all Swift GRBs
visible to AMI are observed, this catalogue provides the first
representative sample of GRB radio properties, unbiased by
multiwavelength selection criteria. We report the detection of six GRB
radio afterglows that were not previously detected by other radio
telescopes, increasing the rate of radio detections by 50 per cent
over an 18-month period. The AMI catalogue implies a Swift GRB radio
detection rate of ≳15 per cent, down to ∼0.2mJy/beam. However,
scaling this by the fraction of GRBs AMI would have detected in the
Chandra & Frail (2012, Cat. J/ApJ/746/156) sample (all radio-observed
GRBs between 1997 and 2011), it is possible ∼44-56 per cent of
Swift GRBs are radio bright, down to ∼0.1-0.15mJy/beam. This
increase from the Chandra & Frail (2012, Cat. J/ApJ/746/156) rate
(∼30 per cent) is likely due to the AMI rapid-response mode, which
allows observations to begin while the reverse-shock is contributing
to the radio afterglow.
Description:
The radio observations of GRBs presented in this paper were obtained
using AMI, which is a radio interferometer consisting of eight 12.8m
diameter dishes with baselines between 18 and 110m. As all the
observations were conducted prior to 2015 June, the effective
frequency range was 13.9-17.5GHz using channels 3-7, each with a
bandwidth of 0.72GHz, with channels 1, 2 and 8 being disregarded due
to their susceptibility to radio frequency interference (RFI).
Through the AMI GRB follow-up programme, we have produced the first
catalogue of radio afterglows that is representative (i.e. not biased
by target selection informed by prior knowledge of the event) of the
radio properties of Swift-detected GRBs down to 0.2mJy/beam at
15.7GHz. This catalogue includes 139 GRBs, 132 of which were detected
with Swift, and is made up of AMI observations up to >90d post-burst.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 227 The AMI 15.7GHz GRB catalogue: GRBs that have
been detected or possibly detected with AMI
table2.dat 91 783 The AMI 15.7GHz GRB catalogue: GRBs that were not
detected with AMI, have a possible steady source
association or a concatenated detection
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See also:
IX/51 : GRB list (1990-2014) (Ruggeri+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB Name of GRB (1)
9- 10 A2 --- Flag Radio detection flag (2)
12- 20 A9 --- Tel Best Swift telescope position (3)
22- 31 A10 "date" Date Date of AMI observation (4)
32 A1 --- n_Date [C] C for Concat (4)
33- 40 F8.2 d Start ? Start of observation in Modified Julian
Date (MJD) format
42- 44 F3.1 h Int ? Length of AMI observation
46- 50 F5.2 d DayPburst ? Number of days post-burst since the
start of the AMI observation
52- 56 F5.2 min MinPburst ? Number of minutes post-burst since the
start of the AMI observation (5)
60 A1 --- Det [*] * indicates the observations where the
listed peak flux is a radio detection (6)
62- 66 F5.2 mJy/beam Fpeak ? Peak flux at 15.7GHz of the
radio afterglow (7)
68- 73 F6.2 mJy/beam e_Fpeak ? Error in the peak flux at 15.7GHz
measurement (1 sigma) (8)
75- 78 F4.1 --- Signi Significance of the flux measured in
units of sigma above the local RMS
80- 83 F4.2 mJy/beam RMS The global RMS of the middle quarter
of the AMI image
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Note (1): All GRBs in this table are classed as long GRBs. All GRB observations
from GRB 130907A onwards followed the updated ALARRM strategy (see
Section 2.1). GRB 130702A and GRB 140320C were discovered by Fermi
and Integral, respectively.
Note (2): Radio detection abbreviations as follows:
A = new radio GRB discovered with AMI
AC = new radio GRB discovered with AMI that was only detected in the
concatenated image
R = radio afterglow first detected with another radio telescope
P = possible new candidate radio GRB discovered with AMI
Note (3): Best Swift telescope position used to search for a radio counterpart
BAT = Swift Burst Alert Telescope
XRT = Swift X-ray Telescope
UVOT = Swift Ultraviolet/Optical Telescope.
For GRB 150413A, the best optical position provided by the MASTER II
robotic telescope (Ivanov et al. 2015, GCN, 17689) was used instead.
Note (4): Date of the AMI observation in yyyy-mm-dd.
C = Concat = concatenation of all epochs with the same pointing (in the case of
GRB 120320A, two observations were taken with different pointings so
the concatenated image is the same as the 2012-04-05 epoch).
Note (5): This time is only provided for those AMI observations where the start
time was ≤0.01 days post-burst.
Note (6): * indicates those GRBs for which the listed AMI peak flux is the
measured flux of a radio source (signal-to-noise ≥4) that is coincident with
the best known Swift position of the GRB (i.e. within 3 positional sigma).
All other listed fluxes are derived from a forced Gaussian fit at the best
known Swift position.
Note (7): Peak flux density as reported by PySE.
Note (8): The 1 sigma error bar is the flux error output by PySE
added in quadrature to the AMI 5% calibration error.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB Name of GRB (1)
9 A1 --- Type Short (S) or long (L) duration GRB
11- 12 A2 --- Flag Radio detection flag (2)
15- 20 A6 --- Tel Best Swift telescope position (3)
22- 31 A10 "date" Date Date of AMI observation (4)
32 A1 --- n_Date [C] C for Concat (4)
33- 40 F8.2 d Start ? Start of observation in Modified Julian
Date (MJD) format
42- 45 F4.1 h Int ? Length of AMI observation
47- 52 F6.2 d DayPburst ? Number of days post-burst since the start
of the AMI observation
56- 60 F5.2 min MinPburst ? Number of minutes post-burst since the
start of the AMI observation (5)
63 A1 --- Det [*] * indicates the observations where the
listed peak flux is a radio detection (6)
65- 70 F6.2 mJy/beam Fpeak Peak flux 15.7GHz of the radio afterglow (7)
72- 79 F8.2 mJy/beam e_Fpeak Error in the peak flux 15.7GHz measurement
(1 sigma) (8)
82- 85 F4.1 --- Signi Significance of the flux measured in units
of sigma above the local RMS
88- 91 F4.2 mJy/beam RMS The global RMS of the middle quarter of
the AMI image
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Note (1): All GRB observations from GRB 130813A onwards followed the updated
ALARRM strategy (see Section 2.1). GRB 140320B was discovered by Integral and
GRB 140508A, GRB 140606B, GRB 140623A, and GRB 140801A were discovered
by Fermi.
Note (2): Radio detection abbreviations
R = radio afterglow first detected with another radio telescope
S = AMI detected coincident radio source is likely steady
C = coincident radio source detected in AMI concatenated image
CS = coincident radio source detected in AMI concatenated image that is
confirmed to be a steady source
N = no detection
Note (3): Best Swift telescope position used to search for a radio counterpart
BAT = Swift Burst Alert Telescope
XRT = Swift X-ray Telescope
UVOT = Swift Ultraviolet/Optical Telescope.
For GRB 130521A, the best optical position provided by Skynet/PROMPT
(James et al., 2013, GCN, 14713) was used instead.
Note (4): Date of the AMI observation in yyyy-mm-dd.
C = Concat = concatenation of all epochs with the same pointing
Note (5): This time is only provided for those AMI observations where the
start time was ≤0.01 days post-burst
Note (6): * indicates those GRBs for which the listed AMI peak flux is the
measured flux of a radio source (signal-to-noise ≥4) that is coincident with
the best known Swift position of the GRB (i.e. within 3 positional sigma).
All other listed fluxes are derived from a forced Gaussian fit at the best
known Swift position.
Note (7): Peak flux density as reported by PySE. The PySE fitting algorithm
failed on the 2012-04-05 and 2012-04-08 AMI observations of GRB 120311A and
all of the GRB 121128A observations. The forced fits were instead conducted
using MIRIAD and the reported significance is just the forced fitted peak flux
divided by the global RMS.
Note (8): The 1 sigma error bar is the flux error output by PySE added in
quadrature to the AMI 5% calibration error.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Aug-2020