Gamma-ray Burst 160221A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Sun 21 Feb 16 23:49:58 UT
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    7378,   Sub_Num: 1
GRB_RA:         232.0803d {+15h 28m 19s} (J2000),
                232.3256d {+15h 29m 18s} (current),
                231.3218d {+15h 25m 17s} (1950)
GRB_DEC:        -28.4445d {-28d 26' 39"} (J2000),
                -28.4996d {-28d 29' 58"} (current),
                -28.2720d {-28d 16' 18"} (1950)
GRB_ERROR:      3.18 [arcmin, radius, statistical only]
GRB_INTEN:      8.73 [sigma]
GRB_TIME:       85790.32 SOD {23:49:50.32} UT
GRB_DATE:       17439 TJD;    52 DOY;   16/02/21
SC_RA:          239.71 [deg] (J2000)
SC_DEC:         -39.91 [deg] (J2000)
SUN_POSTN:      334.74d {+22h 18m 57s}  -10.48d {-10d 28' 50"}
SUN_DIST:        95.68 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:     145.42d {+09h 41m 40s}  +11.32d {+11d 19' 05"}
MOON_DIST:       92.70 [deg]
GAL_COORDS:     340.06, 22.90 [deg] galactic lon,lat of the burst
ECL_COORDS:     236.80, -9.27 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=10.0000 and Time_Error=10.0000.  
COMMENTS:       Possibly real GRB event  
COMMENTS:          
COMMENTS:       NOTE: This INTEGRAL event is temporally(5.0<100sec) coincident with the FERMI_GBM event (trignum=477791389).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 21 Feb 16 23:50:12 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     477791389
GRB_RA:          234.233d {+15h 36m 56s} (J2000),
                 234.484d {+15h 37m 56s} (current),
                 233.458d {+15h 33m 50s} (1950)
GRB_DEC:         -31.117d {-31d 07' 00"} (J2000),
                 -31.169d {-31d 10' 08"} (current),
                 -30.952d {-30d 57' 08"} (1950)
GRB_ERROR:       16.50 [deg radius, statistical plus systematic]
GRB_INTEN:       76 [cnts/sec]
DATA_SIGNIF:     6.70 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        17439 TJD;    52 DOY;   16/02/21
GRB_TIME:        85785.22 SOD {23:49:45.22} UT
GRB_PHI:         112.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      2.24
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      50%  GRB
2nd_MOST_LIKELY:  20%  SGR_1806n20
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,0, 0,0,
SUN_POSTN:       334.74d {+22h 18m 57s}  -10.48d {-10d 28' 50"}
SUN_DIST:         93.19 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      145.42d {+09h 41m 41s}  +11.32d {+11d 19' 03"}
MOON_DIST:        95.04 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      339.86, 19.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      239.30,-11.41 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn160221993/quicklook/glg_lc_medres34_bn160221993.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 156.73,-25.60 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(5.0<100sec) coincident with the INTEGRAL event (trignum=7378).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 21 Feb 16 23:50:23 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     477791389
GRB_RA:          226.570d {+15h 06m 17s} (J2000),
                 226.800d {+15h 07m 12s} (current),
                 225.858d {+15h 03m 26s} (1950)
GRB_DEC:         -19.650d {-19d 38' 59"} (J2000),
                 -19.712d {-19d 42' 41"} (current),
                 -19.457d {-19d 27' 25"} (1950)
GRB_ERROR:       6.37 [deg radius, statistical only]
DATA_SIGNIF:     9.20 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        17439 TJD;    52 DOY;   16/02/21
GRB_TIME:        85785.22 SOD {23:49:45.22} UT
GRB_PHI:         116.00 [deg]
GRB_THETA:        68.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       334.74d {+22h 18m 57s}  -10.48d {-10d 28' 49"}
SUN_DIST:        102.93 [deg]   Sun_angle= 7.2 [hr] (West of Sun)
MOON_POSTN:      145.42d {+09h 41m 41s}  +11.32d {+11d 19' 02"}
MOON_DIST:        85.86 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      341.46, 32.95 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.62, -2.09 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn160221993/quicklook/glg_lc_medres34_bn160221993.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_477791389.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~4 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(5.0<100sec) coincident with the INTEGRAL event (trignum=7378).

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Mon 22 Feb 16 00:33:04 UT
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    7378,   Sub_Num: 2
GRB_RA:         232.0817d {+15h 28m 20s} (J2000),
                232.3270d {+15h 29m 18s} (current),
                231.3233d {+15h 25m 18s} (1950)
GRB_DEC:        -28.4336d {-28d 26' 00"} (J2000),
                -28.4887d {-28d 29' 18"} (current),
                -28.2611d {-28d 15' 39"} (1950)
GRB_ERROR:      2.50 [arcmin, radius, statistical only]
GRB_INTEN:      8.73 [sigma]
GRB_TIME:       85790.32 SOD {23:49:50.32} UT
GRB_DATE:       17439 TJD;    52 DOY;   16/02/21
SC_RA:          239.71 [deg] (J2000)
SC_DEC:         -39.91 [deg] (J2000)
SUN_POSTN:      334.77d {+22h 19m 04s}  -10.47d {-10d 28' 11"}
SUN_DIST:        95.71 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:     145.79d {+09h 43m 09s}  +11.23d {+11d 13' 30"}
MOON_DIST:       92.34 [deg]
GAL_COORDS:     340.06, 22.90 [deg] galactic lon,lat of the burst
ECL_COORDS:     236.80, -9.26 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=10.0000 and Time_Error=10.0000.  
COMMENTS:       refined_coordinates_after_offline_analysis  
COMMENTS:          
COMMENTS:       NOTE: This INTEGRAL event is temporally(5.0<100sec) coincident with the FERMI_GBM event (trignum=477791389).

GCN Circular #19046
S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, T.Favre (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
a gamma ray burst lasting about 10 s has been detected by IBAS in the IBIS/ISGRI data at 23:49:42 UT of February 21, 2016.
The refined coordinates (J2000) are:
```
R.A.=   232.0818 deg
DEC.=   -28.4337 deg
```
with an uncertainty of 2.5 arcmin (90% c.l.).
The burst had a peak flux of 1 counts/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 5e-7 erg/cmq.
A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html
GCN Circular #19047
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the INTEGRAL GRB 160221A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020600
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 INTEGRAL 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 #19049
D.Buckley, S. Potter, M.Kotze, A.Kniazev South African Astronomical Observatory
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
A.Gabovich, V.Yurkov, Yu.Sergienko, D.Varda Blagoveschensk Educational State University, Blagoveschensk
K.Ivanov, N.M.Budnev, O.Gres, V.A.Poleshchuk, S. Yazev Irkutsk State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB160221A (Mereghetti et. al GCN 19046) 61 sec after notice time and 74 sec after trigger time at 2016-02-21 23:51:04 UT. On our second (10s exposure) set we haven`t found optical transient within INTEGRAL error-box (ra=15 28 19 dec=-28 26 40 r=0.053100). The 5-sigma upper limit has been about 16.5 mag on single (10 s images) and 19.0 on coadd image with total exposure 150 s.
The message may be cited.
GCN Circular #19050
A. Melandri (INAF-OAB), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the INTEGRAL-detected burst GRB 160221A (Mereghetti et al. GCN Circ. 19046), collecting 1.3 ks of Photon Counting (PC) mode data between T0+21.3 ks and T0+25.8 ks.
One uncatalogued X-ray source has been detected inside or close to the INTEGRAL error region, it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:
Source 1:
```
  RA (J2000.0):  232.0897  =  15:28:21.54
  Dec (J2000.0): -28.4552  =  -28:27:18.7
  Error: 4.5 arcsec (radius, 90% conf.)
  Count-rate: 0.0151 +/- 0.0040 ct s^-1
  Flux: (5.6 +/- 1.5)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
```
Another uncatalogued was also detected, however this was too far from the GRB position to be the afterglow.
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/00020600.
This circular is an official product of the Swift-XRT team.
GCN Circular #19054
J. Bolmer, T. Kruehler, J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of the INTEGRAL GRB 160221A (Mereghetti et al., GCN #19046) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at 05:12 UT on 2016-02-22, 5.4 hrs after the GRB trigger. They were performed at an average seeing of 1.0" and at an average airmass of 1.4.
No source within the Swift-XRT error circle (Melandri et al., GCN #19050) is detected. Based on 48.0 min of exposure in g'r'i'z' and 43.3 min in JHK, at a mid-time of 06:43 UT, we derive the following preliminary upper limits:
```
g' > 23.6 mag
r' > 24.3 mag
i' > 23.4 mag
z' > 23.4 mag
J  > 21.8 mag
H  > 21.1 mag
K  > 20.0 mag
```
Given limits are in the AB system and calibrated against GROND zeropoints as well as 2MASS field stars. No correction for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.26 mag in the direction of the burst (Schlafly & Finkbeiner 2011) has been applied.
GCN Circular #19056
C. M. Hui (NASA/MSFC) and E. Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi GBM Team:
"At 23:49:45.22 UT on 21 February 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160221A (trigger 477791389 / 160221993), which was also detected by INTEGRAL (Mereghetti et al., GCN 19046). The GBM on-ground location is consistent with the INTEGRAL position.
The angle from the Fermi LAT boresight at the GBM trigger time is 58 degrees.
The GBM light curve consists of a single pulse with a duration (T90) of about 15 s (50-300 keV). The time-averaged spectrum from T0-1.5 s to T0+5.6 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.15 +/- 0.16 and the cutoff energy, parameterized as Epeak, is 67 +/- 7 keV.
The event fluence (10-1000 keV) in this time interval is (1.55 +/- 0.14)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.2 s in the 10-1000 keV band is 4.0 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #19073
A. Melandri (INAF-OAB), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has conducted further observations of the field of the INTEGRAL-detected burst GRB 160221A (Mereghetti et al. GCN Circ. 19046). The observations now extend from T0+21.3 ks to T0+274.5 ks. The source previously reported by Melandri et al. (GCN Circ. 19050), "Source 1", is fading with 3-sigma significance, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=232.0895, -28.4551 which is equivalent to:
```
RA (J2000): 15:28:21.48
Dec(J2000): -28:27:18.4
```
with an uncertainty of 4.1 arcsec (radius, 90% confidence). This position is 80 arcsec from the INTEGRAL position. The source is fading with alpha >0.5.
The results of the XRT-team automatic analysis of the likely afterglow are at http://www.swift.ac.uk/ToO_GRBs/00020600/index_1.php. The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00020600.
This circular is an official product of the Swift-XRT team.

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Jochen Greiner, last update: 25-Feb-2016 [Disclaimer]