GRB 150220A
GCN Circular 17501
Subject
GRB 150220A: Swift ToO observations
Date
2015-02-23T21:35:29Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the IPN GRB 150220A.
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020484
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the IPN event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 17502
Subject
IPN Triangulation of GRB 150220A
Date
2015-02-24T15:29:11Z (10 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa,
and A. Goldstein, on behalf of the Fermi GBM team,
W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:
A long-duration GRB 150220A has been observed by Fermi (GBM trigger
446134898), Konus-Wind, Mars-Odyssey (HEND), and MESSENGER (GRNS), so
far, at about 51696 s UT (14:21:36).
We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
135.496 (09h 01m 59s) -1.597 ( -1d 35' 49")
Corners:
135.673 (09h 02m 42s) -1.932 ( -1d 55' 54")
135.354 (09h 01m 25s) -2.064 ( -2d 03' 51")
135.322 (09h 01m 17s) -1.262 ( -1d 15' 42")
135.642 (09h 02m 34s) -1.124 ( -1d 07' 25")
---------------------------------------------
The error box area is 943 sq. arcmin, and its maximum
dimension is 59 arcmin (the minimum one is 19.6 arcmin).
The Sun distance was 158 deg.
This box may be improved.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB150220_T51704/IPN/
A Swift ToO observation has been scheduled (Evans, GCN Circ. 17501).
The time history and spectrum will be given in forthcoming GCN Circulars.
GCN Circular 17503
Subject
Konus-Wind observation of GRB 150220A
Date
2015-02-24T15:34:07Z (10 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 150220A (IPN triangulation: Hurley et al., GCN
Circ. 17502) triggered Konus-Wind at T0=51704.661 s UT (14:21:44.661).
The burst light curve shows two emission episodes separated by ~100 s
with a total duration of ~160 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150220_T51704/
As observed by Konus-Wind, the burst
had a fluence of 3.00(-0.29,+0.37)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+13.568 s,
of 4.61(-1.05,+1.07)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+147.712 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.86(-0.29,+0.34)
and Ep = 211(-34,+55) keV (chi2 = 49/64 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.2
(chi2 = 48/63 dof)
The spectrum near the maximum count rate
(measured from T0+8.448 to T0+16.640 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.98(-0.17,+0.19)
and Ep = 225(-28,+38) keV (chi2 = 54/64 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.6
(chi2 = 55/63 dof)
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 17504
Subject
GRB 150220A: Swift-XRT observations
Date
2015-02-24T15:39:26Z (10 years ago)
From
Andrea Melandri at INAF-OAB <andrea.melandri@brera.inaf.it>
V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), A. Maselli
(INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), A.P. Beardmore (U. Leicester), A. Amaral-Rogers (U.
Leicester) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
Swift-XRT has performed follow-up observations of the IPN-detected
burst GRB 150220A, collecting 3.0 ks of Photon Counting (PC) mode data
between T0+284.9 ks and T0+300.7 ks.
Three uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:
Source 2:
RA (J2000.0): 135.3781 = 09:01:30.74
Dec (J2000.0): -1.6408 = -01:38:27.0
Error: 6.2 arcsec (radius, 90% conf.)
Count-rate: (6.8 +/- 1.9)e-3 ct s^-1
Flux: (3.26 +/- 0.93)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 3:
RA (J2000.0): 135.5356 = 09:02:8.55
Dec (J2000.0): -1.6164 = -01:36:59.1
Error: 4.9 arcsec (radius, 90% conf.)
Count-rate: (4.7 +/- 1.7)e-3 ct s^-1
Flux: (2.31 +/- 0.81)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 7:
RA (J2000.0): 135.4432 = 09:01:46.37
Dec (J2000.0): -1.6372 = -01:38:13.9
Error: 7.1 arcsec (radius, 90% conf.)
Count-rate: (3.3 [+1.6, -1.3])e-3 ct s^-1
Flux: (6.5 [+3.1, -2.5])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Four catalogued sources were also detected.
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020484.
This circular is an official product of the Swift-XRT team.
GCN Circular 17505
Subject
GRB 150220A: Fermi GBM observation
Date
2015-02-24T17:40:09Z (10 years ago)
From
Oliver Roberts at UCD/Fermi <oliver.roberts@ucd.ie>
O.J. Roberts (UCD) and C. Meegan (UAH) report on behalf of
the Fermi GBM Team:
"At 14:21:35.60 UT on the 20th of February 2015, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 150220A
(trigger 446134898 / 150220598), which was also detected by
IPN (Hurley et al. 2015, GCN 17502) and Konus-Wind
(Golenetskii et al. 2015, GCN 17503 ). The GBM on-ground
location is consistent with the IPN triangulated position.
The angle from the Fermi LAT boresight is 78 degrees.
The GBM light curve shows three pulses occurring over two
main emission episodes. These episodes begin at about
T0-9.5s and T0+105s respectively. The duration (T90) of the
entire light curve is about 145s (50-300 keV).
The time-averaged spectrum of both emission episodes, from
T0-9.5s to T0+37.6s and from T0+104.7s to T0+162.6s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.02 +/- 0.03
and the cutoff energy, parameterised as Epeak, is
192.3 +/- 9.5 keV.
The event fluence (10-1000 keV) in this time interval is
(2.72 +/- 0.07)E-05 erg/cm^2. The 1.024-sec peak photon
flux measured starting from T0+17.9 s in the 10-1000 keV
band is 15.7 +/- 0.4 ph/s/cm^2.
A Band function fits the spectrum equally well with
Epeak = 170.8 +/- 12.8 keV, alpha = -0.97 +/- 0.05
and beta = -2.41 +/- 0.21.
The spectral analysis results presented above are
preliminary; final results will be published in the GBM
GRB Catalog."
GCN Circular 17532
Subject
GRB 150220A: further Swift-XRT observations
Date
2015-03-02T16:17:48Z (10 years ago)
From
Andrea Melandri at INAF-OAB <andrea.melandri@brera.inaf.it>
A. Melandri (INAF/OAB) reports on behalf of the Swift-XRT team:
Swift-XRT observed again the field of the IPN GRB 150220A (Hurley et al. GCN 17502; Roberts & Meegan GCN 17505). The observation started on 2015-02-27 at 14:41 UT, i.e. ~7 days after the burst detection.
For the three sources detected by Swift-XRT, reported in D'Elia et al. (GCN 17504) we did not find any evidence for fading. In particular:
Source 2:
Epoch1: (6.8 +/- 1.9)e-3 ct s^-1
Epoch2: <5.4e-3 ct s^-1 (3sigma upper limit)
Source 3:
Epoch1: (4.7 +/- 1.7)e-3 ct s^-1
Epoch2: <4.1e-3 ct s^-1 (3sigma upper limit)
Source 7:
Epoch1: (3.3 +/- 1.7)e-3 ct s^-1
Epoch2: <3.0e-3 ct s^-1 (3sigma upper limit)
This circular is an official product of the Swift-XRT team.
GCN Circular 17589
Subject
GRB 150220A, the review of the sky area in plate archives
Date
2015-03-16T14:22:03Z (10 years ago)
From
Valentyna Golovnya at Main Astro Obs,Kyiv <golov_v@ukr.net>
V. V. Golovnya, V. M. Andruk (Main Astro Obs., Kyiv)
report:
We have undertaken the review of the sky area of GRB 150220A
(P.A. Evans, GCN Circ. 17501) on astronegatives, collected in Ukrainian
plate archive (1976-1996). All the plates with the possible object
appearance are digitized using Microtek ScanMaker 9800XL TMA and Epson
Expression 10000XL flatbed scanner and the images have been placed
into Golosiiv Plate Archive database DBGPA with open access to them.
2 objects have been found on the plate GUA040C002183 (EPOCH=1993.2192).
Scanning and processing methods were described in [1-3]. The coordinates
and B magnitudes were obtained in the system of TYCHO-2 catalog:
N of Obj. MagTyc RA(J2000) Dec(J2000)
1 (26646) 16.17 09h02m12.961s -01d40���24.457���
2 (26663) 15.96 09 02 13.504 -01 39 51.118
Rms RA=0.093���, rms Dec=0.099���, rms MagTyc=0.21
The list of plates is given in the table:
yyyymmdd/TimeUT-- ---Plates---- Exp. ���Mag --USNO-A2----
19830119/20:30:49 TAS040A000485 28.0 16.4 0825-06684950
19900323/19:14:27 GUA040C003371 12.5 15.6 0825-06686191
19930319/19:23:16 GUA040C002183 21.8 15.7 0825-06683708
Plates:
GUA040C ���The plates archive identifier of DWA (D/F=400/2000,
M=103���/mm) of the Ukrainian NAS Main Astro obs.
(Marsden's number - 83) the plate number [4].
TAS040A -the plates archive identifier of DAZ (D/F=400/3000,
M=68.8���/mm) of the Tashkent Astro obs.
(Marsden's number - 186) the plate number [4].
Exp. - Duration of the maximum exposure (minutes).
Mag - Limited Bmag, derived in the 13 minutes area around the
position: RA(J2000): 09h 01m 51.6s, Dec(J2000): -01d 38��� 03���.
USNO-A2 - Comparison star.
The preview images of 3 areas together with the 13 min. of arc area
from Aladin can be found in
���http://gua.db.ukr-vo.org/img/grb/150220A/index.html���.
The images with full resolution are available via e-mail on demand.
References:
1. Andruk V.��., Butenko G.Z., Yatsenko A.I.: 2010, Kinematics and
Physics of Celestial Bodies, 26/3, 75-81.
2. V.Golovnya, V.Andruk, A.Yatsenko: 2010, Journal of Physical
Studies, 14, N2, 2902.
3. Yatsenko A.I., Andruk V.N., Golovnia V.V., Pakuliak L.K., Ivanov
G.A.: 2011, Kinematics and Physics of Celestial Bodies, 27/3, 49-59.
4. L.Pakuliak: DBGPA V2.0, ���http://gua.db.ukr-vo.org���.
GCN Circular 17645
Subject
GRB 150220A: Optical observations at Kyiv comet station
Date
2015-03-26T13:05:37Z (10 years ago)
From
Valentyna Golovnya at Main Astro Obs,Kyiv <golov_v@ukr.net>
Ya. Romanyuk (Main Astro Obs., Kyiv), A. Baransky (Astr. Obs. of Kyiv
University), I. Kulyk, V. Golovnya, V. Andruk (Main Astro Obs., Kyiv)
report:
We observed the field of GRB 150220A (P.A. Evans, GCN Circ. 17501) with
0.7-m f/4 reflector of Kyiv comet station (Marsden's number ��� 585).
The telescope is equipped with CCD, 1027���1056 pixels with a scale of
0.95"/px. We obtained 21���60sec images in R-filter on Mar., 10, 2015,
from (UTC) 19:08:15 to 19:44:09. Purpose of our observations was not to
search for the afterglow candidate. We would like to find two objects
referred to in (V. V. Golovnya, V. M. Andruk, GCN 17589), which was
found on the old archive photographic plates in close vicinity of the
position of source '1SXPS J090208.3-014021':
RA,Dec(J2000)= 09h02m12.961s -01d40'24.457"
and 09 02 13.504 -01 39 51.118
The preview of archive photographic plates can be found at
'http://gua.db.ukr-vo.org/img/grb/150220A/index.html'
The CCD images were processed with the standard technique and co-added
together to create a frame with higher signal/noise ratio. We did not
find above mentioned objects on the CCD, but we confirmed some of the
positions reported early by P.A. Evans (GCN 17501). The following table
gives the positions listed by Evans, as well as the positions some
of the objects calculated from the CCD.
Position from P. A. Evans, GCN 17501 our work
RA(J2000) Dec(J2000) RA(J2000) Dec(J2000)
1) 09h 01m 31.65s -01�� 39' 07.6" -------- outside our field
2) 09h 01m 30.74s -01�� 38' 27.0" -------- outside our field
3) 09h 02m 08.55s -01�� 36' 59.1" -------- 09h 02m 08.1s -01�� 36' 35"
4) 09h 02m 08.90s -01�� 40' 20.1" -------- extremely faint
5) 09h 01m 28.27s -01�� 39' 06.3" -------- outside our field
6) 09h 02m 25.29s -01�� 41' 14.9" -------- 09h 02m 25.3s -01�� 41' 15"
7) 09h 01m 46.37s -01�� 38' 13.9" -------- 09h 01m 46.4s -01�� 38' 14"