- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sat 20 Feb 16 11:11:09 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 674734, Seg_Num: 0
GRB_RA: 259.854d {+17h 19m 25s} (J2000),
260.090d {+17h 20m 22s} (current),
259.124d {+17h 16m 30s} (1950)
GRB_DEC: -18.123d {-18d 07' 22"} (J2000),
-18.139d {-18d 08' 18"} (current),
-18.072d {-18d 04' 19"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 4204 [cnts] Image_Peak=241 [image_cnts]
TRIGGER_DUR: 1.024 [sec]
TRIGGER_INDEX: 149 E_range: 25-100 keV
BKG_INTEN: 23637 [cnts]
BKG_TIME: 40240.13 SOD {11:10:40.13} UT
BKG_DUR: 8 [sec]
GRB_DATE: 17438 TJD; 51 DOY; 16/02/20
GRB_TIME: 40253.82 SOD {11:10:53.82} UT
GRB_PHI: 10.95 [deg]
GRB_THETA: 40.76 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 20.80 [sigma]
IMAGE_SIGNIF: 10.83 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +2 +0 +0 +1 -32 +0
SUN_POSTN: 333.28d {+22h 13m 06s} -11.03d {-11d 01' 51"}
SUN_DIST: 70.77 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 126.04d {+08h 24m 11s} +15.40d {+15d 24' 07"}
MOON_DIST: 136.02 [deg]
MOON_ILLUM: 95 [%]
GAL_COORDS: 5.91, 10.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 260.33, 4.98 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 37.14,20.43 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sat 20 Feb 16 11:14:28 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 674734, Seg_Num: 0
GRB_RA: 259.854d {+17h 19m 25s} (J2000),
260.090d {+17h 20m 22s} (current),
259.124d {+17h 16m 30s} (1950)
GRB_DEC: -18.123d {-18d 07' 22"} (J2000),
-18.139d {-18d 08' 18"} (current),
-18.072d {-18d 04' 19"} (1950)
GRB_DATE: 17438 TJD; 51 DOY; 16/02/20
GRB_TIME: 40253.82 SOD {11:10:53.82} UT
TRIGGER_INDEX: 149
GRB_PHI: 10.95 [deg]
GRB_THETA: 40.76 [deg]
DELTA_TIME: 71.00 [sec]
TRIGGER_DUR: 1.024 [sec]
SOLN_STATUS: 0x3
RATE_SIGNIF: 20.80 [sigma]
IMAGE_SIGNIF: 10.83 [sigma]
LC_URL: sw00674734000msb.lc
SUN_POSTN: 333.28d {+22h 13m 07s} -11.03d {-11d 01' 48"}
SUN_DIST: 70.77 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 126.07d {+08h 24m 18s} +15.40d {+15d 23' 49"}
MOON_DIST: 136.00 [deg]
MOON_ILLUM: 95 [%]
GAL_COORDS: 5.91, 10.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 260.33, 4.98 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 37.14,20.43 [deg].
- GCN Circular #19029
J. R. Cummings (NASA/UMBC), A. Y. Lien (GSFC/UMBC),
D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf
of the Swift Team:
At 11:10:53 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160220B (trigger=674734). Swift did not slew immediately
due to an observing constraint.
The BAT on-board calculated location is
RA, Dec 259.854, -18.123 which is
RA(J2000) = 17h 19m 25s
Dec(J2000) = -18d 07' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 30 sec. The peak count rate
was ~6000 counts/sec (15-350 keV), at ~6 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+46.5
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
- GCN Circular #19033
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team:
Using 4686 s of XRT Photon Counting mode data and 8 UVOT images, we find
an astrometrically corrected X-ray position (using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =
259.86518, -18.12401 which is equivalent to:
RA (J2000): 17 19 27.64
Dec (J2000): -18 07 26.5
with an uncertainty of 1.5 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
- GCN Circular #19036
J. R. Cummings (NASA/UMBC) reports on behalf of the Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 160220B (Cummings et al.
GCN Circ. 19029), from 3.3 ks to 16.9 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. Using 4686 s of PC mode
data and 8 UVOT images, we find an enhanced XRT position (using the
XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 259.86518, -18.12401 which is equivalent to:
RA (J2000): 17h 19m 27.64s
Dec(J2000): -18d 07' 26.5"
with an uncertainty of 1.5 arcsec (radius, 90% confidence).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.37 (+0.18, -0.17).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.17 (+0.25, -0.23). The
best-fitting absorption column is 4.3 (+1.2, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 2.6 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.6 x 10^-11 (6.3 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.3 (+1.2, -1.1) x 10^21 cm^-2
Galactic foreground: 2.6 x 10^21 cm^-2
Excess significance: 2.5 sigma
Photon index: 2.17 (+0.25, -0.23)
If the light curve continues to decay with a power-law decay index of
1.37, the count rate at T+24 hours will be 2.7 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.7 x
10^-14 (1.7 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00674734.
This circular is an official product of the Swift-XRT team.
- GCN Circular #19037
M. De Pasquale (MSSL-UCL) and J. Cummings (GSFC/UMBC) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160220B
3.33 ks after the BAT trigger (Cummings et al., GCN Circ. 19029).
No optical afterglow consistent with the XRT position (Evans et al.
GCN Circ. 19033) is detected in the UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the
summed UVOT exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 3735 5370 393 >21.0
v 4145 10454 1082 >20.1
b 3530 5165 393 >20.4
u 4882 16950 451 >20.1
w1 4555 16884 1504 >20.9
m2 4350 11207 933 >20.7
w2 5499 32840 1170 >20.9
We note the presence of an uncatalogued source of magnitude 20.2 +/- 0.20
in white filter, at coordinates RA = 17h 19m 28.07, Dec = -18d 07m 25.5s
(J2000), which is 5" from the enhanced XRT position.
The magnitudes above are not corrected for the substantial Galactic
extinction
due to the reddening of E(B-V) = 0.32 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #19042
P. Wiseman, J. Greiner (both MPE Garching) report on behalf of the GROND
team:
We observed the field of GRB 160220B (Swift trigger 674734; Cummings et
al., GCN #19029) 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 07:12 UT on 2016-02-21, ~20 hrs after the GRB
trigger. They were performed at an average seeing of 1.5" and at an
average airmass of 1.8.
We detect a single point source at the southern edge of the 1.5" enhanced
Swift-XRT error circle reported by Evans et al. (GCN #19033), at the
position RA, Dec (J2000) = 259.86531, -18.12433, which is equivalent to:
RA = 17h 19m 27.67s
Dec = -18d 07m 27.6s,
with an uncertainty of 0.3" in each coordinate.
Based on 72.00 min of total exposures at a mid-time of 07:54 UT, we
estimate a preliminary magnitude (AB system) of:
r' = 20.0 +/- 0.1
No statement about the variability of this source can be made at this time.
The given magnitude is calibrated against GROND zeropoints and is not
corrected for the expected Galactic foreground extinction corresponding to
a reddening of E_(B-V)=0.25 mag in the direction of the burst (Schlafly &
Finkbeiner 2011).
- GCN Circular #19043
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160220B (trigger #674734)
(Cummings, et al., GCN Circ. 19029). The BAT ground-calculated position is
RA, Dec = 259.851, -18.123 deg which is
RA(J2000) = 17h 19m 24.2s
Dec(J2000) = -18d 07' 21.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 38%.
The mask-weighted light curve shows a double-peaked structure from T-10 to
T+40 seconds. The spacecraft slewed away from the burst location at ~T+145
sec due to a pre-planned maneuver. T90 (15-350 keV) is 31.4 +- 2.6 sec
(estimated error including systematics).
The time-averaged spectrum from T-7.58 to T+37.54 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.75 +- 0.20,
and Epeak of 168.7 +- 56.3 keV (chi squared 39.67 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 7.0 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+6.46 sec in the 15-150 keV band is
6.6 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.20 +- 0.05 (chi squared 56.26 for 57 d.o.f.). All the quoted errors
are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/674734/BA/
- GCN Circular #19045
A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
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 160220B (Swift-BAT trigger #674734:
Cummings et al., GCN 19029; Lien et al., GCN 19043)
triggered Konus-Wind at T0=40259.435 s UT (11:10:59.435).
The burst light curve shows a single pulse
started at ~T0-12.8 s with a total duration of ~33.3 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/GRB160220_T40259/
As observed by Konus-Wind, the burst
had a fluence of 1.49(-0.11,+0.11)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.896 s,
of 4.32(-1.91,+1.92)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+16.640 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.84 (-0.22,+0.25)
and Ep = 197 (-20,+26) keV (chi2 = 47/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.4
(chi2 = 47/61 dof)
The spectrum near the maximum count rate
(measured from T0+0.256 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.65 (-0.21,+0.24)
and Ep = 208 (-19,+23) keV (chi2 = 57/61 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.5
(chi2 = 57/60 dof)
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
- GCN Circular #19051
M. De Pasquale, A.A. Breeveld (MSSL-UCL) and J. Cummings
(GSFC/UMBC) report on behalf of the Swift/UVOT team:
Following the detection of a source at the southern edge of the 1.5''
Swift-XRT error circle (Evans et al. GCN circ. 19033) by GROND
(Wiseman and Greiner, GCN Circ. 19042) we have re-analysed
our UVOT observations We caution that the anlysis is complicated
by a crowded field and large noise.
About at the sourthern edge of the XRT error circle we detect a source
RA = 17h 19m 27.64s (259.86517)
Dec = -18d 07m 30 s (-18.12500)
with an error of ~1''. The position of this source is
copatible with that of the oject detected by GROND.
Magnitudes of this source are given in the table below.
Filter T_start(s) T_stop(s) Exp(s) Mag
v 4145 10454 1082 18.7 +/- 0.2
b 3530 5165 393 19.4 +/- 0.2
The same source is detected in successive exposures:
v 39730 62085 1072 18.7 +/- 0.2
b 44464 45371 885 19.4 +/- 0.2
As the source does not seem to have changed in brightness, we do
not think it is the optical afterglow of GRB160220B.
Magnitudes above are given in the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373).
- GCN Circular #19052
P. Wiseman, J. Bolmer and J. Greiner (all MPE Garching) report on behalf
of the GROND team:
We once again observed the field of GRB 160220B (Swift trigger 674734;
Cummings et al., GCN #19029) 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).
Based on 36.00 min of total exposures in r', at a mid-time of 08:55 UT
on 2016-02-22, ~1.9 days after the trigger, we do not detect any fading
in the source reported by Wiseman et al. (GCN #19042), placing a limit
on any magnitude change to < 0.1 mag in 24 hrs, in agreement with UVOT
observations ( De Pasquale et al., GCN #19051).
We therefore agree that this source is likely not the afterglow of GRB
160220B.
- GCN Circular #19053
M. De Pasquale report on behalf of the Swift/UVOT team: The title of the
previous GCN Circ. 19051 should be "Further Swift/UVOT observations of
GRB 160220B". We apologize for the mistake.
Previous IAU Circulars 