GRB 160121A
GCN Circular 18912
Subject
GRB 160121A: Swift detection of a burst
Date
2016-01-21T14:02:13Z (9 years ago)
From
David Burrows at PSU/Swift <burrows@astro.psu.edu>
L. M. Z. Hagen (PSU), D. N. Burrows (PSU), P.A. Evans (U Leicester),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
F. E. Marshall (NASA/GSFC), L. M. McCauley (PSU),
K. L. Page (U Leicester) and B. Sbarufatti (INAF-OAB/PSU) report on
behalf of the Swift Team:
At 13:50:37 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160121A (trigger=671231). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 109.079, -23.578 which is
RA(J2000) = 07h 16m 19s
Dec(J2000) = -23d 34' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single FRED-
shaped peak with a duration of about 15 sec. The peak count rate
was ~1700 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 13:52:08.7 UT, 91.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 109.0890, -23.5920
which is equivalent to:
RA(J2000) = 07h 16m 21.35s
Dec(J2000) = -23d 35' 31.3"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 60 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 5.26
x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of nominal 250.000 seconds with the U filter
starting 151 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Data from the 2.7'x2.7' sub-image are
not available at this time. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18.0 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.66.
Burst Advocate for this burst is L. M. Z. Hagen (lea.zernow.hagen AT gmail.com).
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 18913
Subject
GRB 160121A: MASTER-Amur observations
Date
2016-01-21T14:21:03Z (9 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina,
P.Balanutsa, A.Kuznetsov, V.V.Chazov,
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University
V.Krushinski, I.Zalozhnih, A. Popov
Ural Federal University, Kourovka
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik
Kislovodsk Solar Station of the Pulkovo Observatory
D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Blagoveschensk was pointed to the GRB160121A (Hagen et al GCN
18912) 22 sec after notice time and 34 sec after trigger time at 2016-01-21 13:51:15 UT.
On our first (10s exposure) set we haven`t found optical transient within
SWIFT.
The 5-sigma upper limit has been about 15.3 mag
The message may be cited.
GCN Circular 18917
Subject
GRB 160121A: 1.8m MOA optical afterglow detection
Date
2016-01-21T22:19:41Z (9 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
S. R. Oates, J. C. Tello (IAA-CSIC Granada), P. Tristram (Mt. John Univ. Observatory),
I. Bond (Massey Univ.), S. Takahiro (Osaka Univ.), P. Yock (Univ. of Auckland) and
A. J. Castro-Tirado (IAA-CSIC & ISA-UMA) report on behalf of a larger collaboration:
We observed the field of GRB 160121A (Hagen et al., GCN 18912) with the 1.8m MOA-II
telescope at Mt John University Observatory in New Zealand. A series of 60s exposures
were taken with the R-band filter beginning 4.38 min (13:55:0 UT on 21-01-2016) after
the Swift trigger 671231.
We detect a single source at the edge of the Swift-XRT error circle (Hagen et al., GCN 18912),
which we propose is the afterglow, at coordinates:
RA (J2000.0) = 07:16:21.16
Dec (J2000.0) = -23:35:31.6
with an error of around 0.5".
In the first exposure, ~292s after the trigger, we measure R ~19.7+\-0.2.
The light curve appears to increase slightly in brightness, plateauing
around 500s with a magnitude ~19. The light curve begins to decay around
1200s after the trigger.
Magnitudes and upper limits are calibrated against USNO-B1 catalogue and
are not corrected for the significant Galactic extinction corresponding to a
reddening of E_B-V = 0.53 mag (Schlafly & Finkbeiner 2011).
GCN Circular 18918
Subject
GRB 160121A: Enhanced Swift-XRT position
Date
2016-01-21T22:44:41Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2518 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 160121A, 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 = 109.08819, -23.59221 which is equivalent
to:
RA (J2000): 07h 16m 21.17s
Dec (J2000): -23d 35' 32.0"
with an uncertainty of 1.6 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 was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 18919
Subject
GRB 160121A: Swift-BAT refined analysis
Date
2016-01-21T22:47:14Z (9 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), L. M. Z. Hagen (PSU), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), (i.e. the Swift-BAT team):
Using the data set from T-239 to T+340 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160121A (trigger #671231)
(Hagen, et al., GCN Circ. 18912). The BAT ground-calculated position is
RA, Dec = 109.080, -23.590 deg which is
RA(J2000) = 07h 16m 19.1s
Dec(J2000) = -23d 35' 25.5"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 91%.
The mask-weighted light curve shows a single peak starting at T-4 sec,
peaking at T+3 sec and returning to baseline by T+14 sec. T90 (15-350 keV)
is 12.0 +- 2.4 sec (estimated error including systematics).
The time-averaged spectrum from T-0.03 to T+14.97 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.77 +- 0.13. The fluence in the 15-150 keV band is 6.1 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.76 sec in the 15-150 keV band
is 1.2 +- 0.2 ph/cm2/sec. 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/671231/BA/
GCN Circular 18920
Subject
GRB 160121A: TSHAO optical afterglow confirmation
Date
2016-01-22T00:36:48Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin
(Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI)
report on behalf of a larger GRB follow-up collaboration:
We observed the field of the Swift GRB 160121A (Hagen et al., GCN 18912)
with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory
starting on Jan. 21 (UT) 16:04:44. We obtained several images in R filter.
We detect afterglow (Oates et al., GCN 18917) in a combined image within
center of the enhanced Swift-XRT position (Osborne et al., GCN 18918).
Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err
(mid, days) (s)
2016-01-21 16:04:44 0.12598 R 29*180 20.26 0.22
The photometry is based on nearby USNO-B1.0 stars.
USNO-B1.0_id R2
0664-0122909 16.87
0664-0122918 16.73
0664-0122943 17.72
0664-0123015 18.03
0663-0123485 16.91
GCN Circular 18921
Subject
GRB 160121A: GROND Afterglow observations
Date
2016-01-22T08:36:42Z (9 years ago)
From
Corentin Delvaux at MPE <delvaux@mpe.mpg.de>
C. Delvaux (MPE Garching), S. Schmidl (TLS Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 160121A (Swift trigger 671231; Hagen et al.,
GCN #18912) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 04:09 UT on 22-01-2016, 14.3hrs after the GRB
trigger. They were performed at an average seeing of 0.9" and at an
average airmass of 1.0.
We clearly detect the afterglow at the position reported by Oates et al.
(GCN#18917) and Mazaeva et al. (GCN#18920).
Based on the first 72 min of total exposures in g'r'i'z' and 60 min in
JHK, at a midtime of 04:49 UT, we estimate preliminary magnitudes and
upper limits (all in AB system) of
g' = 22.6 +/- 0.1 mag
r' = 21.2 +/- 0.1 mag,
i' = 21.1 +/- 0.1 mag,
z' = 21.0 +/- 0.1 mag,
J = 19.6 +/- 0.1 mag,
H = 19.3 +/- 0.1 mag,
K > 19.1 mag.
The given magnitudes and limits are derived based on calibrating the
images against GROND zeropoints and 2MASS field stars and are not
corrected for the Galactic foreground extinction corresponding to a
reddening of E_(B-V)= 0.53 in the direction of the burst (Schlafly and
Finkbeiner 2011).
GCN Circular 18922
Subject
GRB 160121A: Swift/UVOT Upper Limits
Date
2016-01-22T09:26:13Z (9 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (IAA-CSIC/UCL-MSSL) and L. M. Z. Hagen (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160121A
152 s after the BAT trigger (Hagen et al., GCN Circ. 18912).
No optical afterglow consistent with the optical position
reported by MOA (Oates et al., GCN Circ. 18917) is detected
in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
u_FC 152 401 246 >19.7
v 435 830 78 >18.6
u 152 918 356 >19.9
w1 484 754 58 >18.3
m2 459 854 78 >18.4
w2 410 805 78 >18.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.53 in the direction of the burst
(Schlafly and Finkbeiner 2011).
GCN Circular 18923
Subject
GRB 160121A: Swift-XRT refined Analysis
Date
2016-01-22T13:31:33Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. D'Avanzo (INAF-OAB), T.G.R. Roegiers (PSU), L.M. McCauley (PSU),
J.A. Kennea (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester),
A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA)
and L.M.Z. Hagen report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 160121A (Hagen et al. GCN
Circ. 18912), from 75 s to 46.0 ks after the BAT trigger. The data
comprise 80 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 18918).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.9 (+0.8, -0.4). At T+209 s the decay
flattens to an alpha of 0.31 (+/-0.07) before breaking again at T+20.7
ks to a final decay with index alpha=2.1 (+1.6, -1.2).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.00 (+0.24, -0.18). The
best-fitting absorption column is 5.8 (+1.6, -0.5) x 10^21 cm^-2,
consistent with the Galactic value of 5.3 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 4.2 x 10^-11 (7.0 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 5.8 (+1.6, -0.5) x 10^21 cm^-2
Galactic foreground: 5.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 2.00 (+0.24, -0.18)
If the light curve continues to decay with a power-law decay index of
2.1, the count rate at T+24 hours will be 3.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x
10^-13 (2.1 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/00671231.
This circular is an official product of the Swift-XRT team.
GCN Circular 18924
Subject
GRB 160121A: RATIR Optical Observations
Date
2016-01-22T18:19:22Z (9 years ago)
Edited On
2024-11-07T18:57:47Z (7 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (UCB), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and
Vicki Toy (UMD) report:
We observed the field of GRB 160121A (Hagen et al., GCN Circular 18912)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astronómico Nacional on Sierra San Pedro Mártir from 2016/01 22.13 to
2016/01 22.29 UTC (13.28 to 17.14 hours after the BAT trigger),
obtaining a total of 2.92 hours exposure in the r, i, and z bands.
We detect a source at 07:16:21.16 -23:35:31.5 J2000 (�0.5 arcsec),
consistent with the enhanced Swift-XRT position (Osborne et al., GCN
Circular 18918). In comparison with the USNO-B1 and 2MASS catalogs, we
obtain the following magnitudes and 3-sigma upper limits:
r = 21.73 ± 0.13
i = 21.10 ± 0.08
z > 19.80
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
Our observations have almost the same midpoint as the GROND observations
reported by Delvaux et al. (GCN Circular 18921). The i band observations
are consistent, but our r band measurement is surprisingly 0.6 mag
fainter than theirs.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 18925
Subject
GRB 160121A: redshift from the 10.4m GTC
Date
2016-01-22T22:08:42Z (9 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
R. Sanchez-Ramirez, S. R. Oates, J. C. Tello (IAA-CSIC Granada), S. Geier
(GRANTECAN), P. Tristam (Mt. John Univ. Observatory) and A. J.
Castro-Tirado (IAA-CSIC and ISA-UMA) report on behalf of a larger
collaboration:
We observed the field of GRB 160121A (Hagen et al. GCN 18912) with the
10.4m GTC telescope (+OSIRIS) at La Palma. 6x900s spectra were taken at
the position of the optical afterglow, detected by the 1.8m MOA (Oates et
al. GCNC 18917), starting at 22:30 UT (i.e. 8.7 h post-burst). We identify
Mg II and several Fe-II absorption lines at z = 1.960 which we propose to
be the host galaxy redshift. An intervening system at z = 1.645 is also
detected.
GCN Circular 18933
Subject
GRB 160121A: TSHAO optical observation
Date
2016-01-24T21:29:54Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin
(Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI)
report on behalf of a larger GRB follow-up collaboration:
We observed the field of the Swift GRB 160121A (Hagen et al., GCN
18912) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical
Observatory starting on Jan. 22 (UT) 16:17:07. We obtained several
images in R filter. We do not detect afterglow (Oates et al., GCN
18917; Mazaeva et al., GCN 18920) in a combined image. Preliminary upper
limit is following
Date UT start t-T0 Filter Exp. OT UL (3 sigma)
(mid, days) (s)
2015-01-22 16:17:07 1.13572 R 30*180 n/d 21.2
The photometry is based on nearby USNO-B1.0 stars (see GCN 18920).
GCN Circular 18935
Subject
GRB 160121A: RATIR Optical Observations
Date
2016-01-25T18:37:38Z (9 years ago)
Edited On
2024-11-07T19:54:25Z (7 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and
Vicki Toy (UMD) report:
We observed the field of GRB 160121A (Hagen et al., GCN Circular 18912)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astronómico Nacional on Sierra San Pedro Mártir from 2016/01 24.13 to
2016/01 24.42 UTC (61.29 to 68.12 hours after the BAT trigger),
obtaining a total of 4.27 hours exposure in the r, i and z bands.
We no longer detect the source previously reported by Watson et al.
(GCN Circular 18924). In comparison with the USNO-B1 and 2MASS catalogs,
we obtain the following 3-sigma upper limits:
r > 22.97
i > 22.94
z > 20.10
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.