J/ApJ/873/60 Improved Fermi-GBM GRB localizations using BALROG (Berlato+, 2019)
Improved Fermi-GBM GRB localizations using BALROG.
Berlato F., Greiner J., Burgess J.M.
<Astrophys. J., 873, 60-60 (2019)>
=2019ApJ...873...60B 2019ApJ...873...60B (SIMBAD/NED BibCode)
ADC_Keywords: GRB; Positional data
Keywords: catalogs; gamma-ray burst: general; methods: data analysis
techniques: miscellaneous
Abstract:
The localizations of gamma-ray bursts (GRBs) detected with the
Gamma-ray Burst Monitor (GBM) on board the Fermi satellite are known
to be affected by significant systematic errors of 3°-15°.
This is primarily due to the mismatch of the employed Band function
templates and the actual GRB spectrum. This problem can be avoided by
simultaneously fitting for the location and the spectrum of a GRB, as
demonstrated with an advanced localization code, BALROG. Here, we
analyze in a systematic way a sample of 105 bright GBM-detected GRBs
for which accurate reference localizations are available from the
Swift observatory. We show that the remaining systematic error can be
reduced to ∼1°-2°.
Description:
Only Swift-localized GRBs are used in this work, because Swift
localizations are much more precise compared to most of the other
instruments and can be used as reference to assess BALROG's
performance. Swift's uncertainties are typically of the order of a few
arcminutes for Swift/BAT and a few arcseconds for Swift/XRT. These
errors are always much smaller than GBM's.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 86 105 *List of the GRBs analyzed
--------------------------------------------------------------------------------
Note on table2.dat: BALROG is the BAyesian Location Reconstruction Of GRBs
code (Burgess+ 2018MNRAS.476.1427B 2018MNRAS.476.1427B); DoL is the Daughter of Location
algorithm (Connaughton+ 2015, J/ApJS/216/32)
--------------------------------------------------------------------------------
See also:
IX/20 : The Fourth BATSE Burst Revised Catalog (Paciesas+ 1999)
J/ApJS/199/18 : The Fermi GBM catalog (Paciesas+, 2012)
J/ApJS/207/39 : IPN supplement to the Fermi GBM (Hurley+, 2013)
J/ApJS/211/13 : The second Fermi/GBM GRB catalog (4yr) (von Kienlin+, 2014)
J/ApJS/216/32 : Localizations of GRBs with Fermi GBM (Connaughton+, 2015)
J/ApJ/806/52 : 8 Fermi GRB afterglows follow-up (Singer+, 2015)
J/A+A/588/A135 : Fermi/GBM GRB time-resolved spectral catalog (Yu+, 2016)
J/ApJS/229/31 : IPN supplement to the 2nd Fermi GBM catalog (Hurley+, 2017)
J/ApJ/893/46 : The fourth Fermi-GBM GRB cat.: 10 years (von Kienlin+, 2020)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- Trig Trigger number (YYMMDDddd;
<Fermi bnYYMMDDddd> in Simbad) (1)
10 A1 --- f_Trig [*] * : short GRB
12- 16 F5.1 deg RASdeg Swift right ascension (J2000)
18- 22 F5.1 deg DESdeg Swift declination (J2000)
24- 28 F5.1 deg RAdeg BALROG right ascension (J2000)
30- 33 F4.1 deg e_RAdeg [0.2/53] RAdeg uncertainty
35- 39 F5.1 deg DEdeg BALROG declination (J2000)
41- 43 F3.1 deg e_DEdeg [0.2/8] DEdeg uncertainty
45- 47 F3.1 deg Offset [0.1/7.4] BALROG offset
49- 52 A4 --- Model Model (2)
54- 58 F5.1 deg RADdeg ? DoL right ascension (J2000)
60- 64 F5.1 deg DEDdeg ? DoL declination (J2000)
66- 68 F3.1 deg e_posDoL [1/9.6]? DoL position uncertainty
70- 73 F4.1 --- OffDoL [0.4/19.2]? DoL offset
75- 80 E6.2 10-3J/m2 Fluence [3.2e-07/0.0025] Fluence in erg/cm2
82- 86 E5.2 ph/cm2/s Flux [2.7/1100] Peak flux
--------------------------------------------------------------------------------
Note (1): GRBs after 130609902 constitute sample 2.
Note (2): The abbreviations have the following meanings:
cpl = cutoff power law,
band = band function,
pl = power law.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 23-Oct-2023