GRB 160601A
GCN Circular 19478
Subject
GRB 160601A: Swift detection of a short hard burst
Date
2016-06-01T15:00:57Z (9 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
D. Kocevski (NASA/GSFC/ORAU), P.A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), B. Mingo (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL), T. G. R. Roegiers (PSU)
and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 14:43:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160601A (trigger=688452). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 235.034, +64.495 which is
RA(J2000) = 15h 40m 08s
Dec(J2000) = +64d 29' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 0.2 sec. The peak count rate
was ~7000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 14:44:16.3 UT, 74.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 234.9351, 64.5401 which
is equivalent to:
RA(J2000) = 15h 39m 44.43s
Dec(J2000) = +64d 32' 24.2"
with an uncertainty of 3.3 arcseconds (radius, 90% containment). This
location is 223 arcseconds from the BAT onboard position. 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. This position is more than
2-sigma away from the BAT position, and so possibly unrelated to the
trigger.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.04
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 250 seconds with the U filter
starting 78 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. 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 mag.
Burst Advocate for this burst is D. Kocevski (dankocevski 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 19479
Subject
GRB 160601A: MASTER-Net observations
Date
2016-06-01T15:19:26Z (9 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
A.Gabovich, V.Yurkov, Yu.Sergienko
Blagoveschensk Educational State University, Blagoveschensk
V. Lipunov, E.Gorbovskoy, N.Tyurina, P.Balanutsa, A.Kuznetsov,
V.Kornilov, D.Kuvshinov, V.V.Chazov, E.Popova,
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
K.Ivanov, N.M.Budnev, O.Gres, V.A.Poleshchuk
Irkutsk State University
A. Tlatov, V.Senik, D. Dormidontov, A.V. Parhomenko
Kislovodsk Solar Station of the Pulkovo Observatory
D.Buckley, S. Potter, A.Kniazev
South African Astronomical Observatory
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Ricardo Podesta, Claudio Mallamaci, Federico Podest, Carlos Lopez
Observatorio Astronomico Felix Aguilar (OAFA)
MASTER-Amur robotic telescope (MASTER-Net: http://observ.pereplet.ru)
was pointed to the GRB160601A (Kocevski et al., GCN19478) 67 sec after
notice time and 81 sec after trigger time at 2016-06-01 14:44:23 UT.
On our first (20s and 70s exposures) set we haven`t found optical
transient within SWIFT error-box (ra=15h 39m 44.43s dec=+64d 32' 24.2"
r=3.3 arcsec) The 5-sigma upper limit is 17.5mag.
MASTER-Tunka robotic telescope was pointed to the GRB160601.61 55 sec
after notice time and 73 sec after trigger time at 2016-06-01 14:44:16 UT,
on the first images (20s) there is also no OT .
The message may be cited.
GCN Circular 19480
Subject
GRB 160601A: MITSuME Okayama upper limits
Date
2016-06-01T15:56:56Z (9 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of MITSuME and OISTER collaboration:
We observed the field of GRB 160601A (Kocevski et al., GCNC 19478)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2016-06-01 14:43:48 UT (~46 sec after
the burst). We did not find any new point source within the XRT
circle (Kocevski et al., GCNC 19478) in all the three bands.
Three sigma upper limits of the OT are listed below.
We used SDSS-DR8 catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Ic
-----------------------------------------------------
0.01716 15:07:45 2460.0 >20.5 >20.3 >19.3
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 19482
Subject
GRB 160601A: MITSuME Okayama Ks-band upper-limit
Date
2016-06-01T17:09:41Z (9 years ago)
From
Kenshi Yanagisawa at OAO/NAOJ <yanagi@oao.nao.ac.jp>
K. Yanagisawa, D. Kuroda, Y. Shimizu, H. Izumiura(OAO/NAOJ),
M. Yoshida (Hiroshima), K. Ohta(Kyoto) and N. Kawai(Tokyo Tech.)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 160601A (Kocevski et al., GCN 19478)
in Ks-band with a wide-field near infrared imager at Okayama
Astrophysical Observatory (Japan). The imager has effective
aperture of 0.91 m.
Observations started from 14:57 UT on 1st June, 14 min after
the BAT trigger, to 15:22 UT. The total exposure of 10.0 min
was successfully obtained.
In our co-add image, we did not find any new point source within
the XRT error circle down to the limiting magnitude of
Ks=16.1 (Vega, S/N=3). The photometric calibration was made
against 2MASS field stars.
T0+[sec] MID-UT T-EXP[sec] Ks
---------------------------------------------------
+1,560 15:09 600.0 >16.1
---------------------------------------------------
T0+ : Elapsed time after the burt [sec]
T-EXP: Total Exposure time [sec]
GCN Circular 19483
Subject
GRB 160601A: Mondy optical observations
Date
2016-06-01T19:54:08Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev
(ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of the Swift GRB 160601A (Kocevski et al., GCN
19478) with AZT-33IK telescope of Sayan observatory (Mondy) starting on
June, 01 (UT) 15:00:41. We obtained several images in R-filter under
good weather conditions and FWHM of 1.5 arcsec. Using only part of
images available we marginally detect (S/N ~2) a source at the edge of
Swift-XRT position (Kocevski et al., GCN 19478). Coordinates of the
source are (J2000) 15:39:44.43 +64:32:19.3 with uncertainty of 1 arcsec.
Preliminary photometry of the source is R~22.3, and details of
observations are following
Date UT start t-T0 Filter Exp. OT(?) UpperLimit (3 sigma)
(mid, days) (s)
2016-06-01 15:00:41 0.03026 R 16*60 22.3 21.8
Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R:
SDSS-DR9_id R(Lupton)
J153959.67+643325.7 16.72
J153956.37+643102.2 17.00
J153931.88+643247.0 17.02
J153927.50+643304.3 19.23
J153942.70+643016.4 16.27
We will update the results after all the data will be available.
GCN Circular 19484
Subject
GRB 160601A: Enhanced Swift-XRT position
Date
2016-06-01T20:45:22Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 609 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 160601A, 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 = 234.93505, +64.54133 which is equivalent
to:
RA (J2000): 15h 39m 44.41s
Dec (J2000): +64d 32' 28.8"
with an uncertainty of 3.3 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 19485
Subject
GRB160601A: NOT detection of an afterglow candidate
Date
2016-06-01T22:49:29Z (9 years ago)
From
Steve Schulze at U of Iceland <sts30@hi.is>
D. Malesani (DARK/NBI), S. Schulze (PUC, MAS), N. R. Tanvir (U Leicester), D. Xu (NAOC/CAS), A. A. Djupvik (NOT) and P. Jakobsson (U Iceland) report on behalf a larger collaboration:
We observed the field of the short GRB 160601A (Kocevski et al., GCN 19478) with the Nordic Optical Telescope (NOT) equipped with the AlFOSC imager. Our first 900-s exposure in the r band started on Jun 1.885 UT (6.5 hr after the GRB).
Close to the UVOT-enhanced XRT position (Evans et al., GCN 19484), we detect two sources, at coordinates:
(1)
RA = 15:39:43.97
Dec = +64:32:30.5
r mag = 22.85 +/- 0.10 (AB)
(2)
RA = 15:39:44.91
Dec = +64:32:32.1
r mag = 23.04 +/- 0.09 (AB)
Visual inspection of the SDSS at the above locations shows a faint, marginally detected object coincident with source (2), but no object at the position of source (1). We thus consider source (1) to be a potential afterglow candidate, though further observations are needed to test its variability.
GCN Circular 19486
Subject
GRB 160601A: Swift-XRT refined Analysis
Date
2016-06-02T00:29:54Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. Maselli (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows
(PSU), T.G.R. Roegiers (PSU), P.A. Evans (U. Leicester), S.L. Gibson
(U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), P.
D'Avanzo (INAF-OAB) and D. Kocevski report on behalf of the Swift-XRT
team:
We have analysed 7.9 ks of XRT data for GRB 160601A (Kocevski et al.
GCN Circ. 19478), from 94 s to 23.6 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 19484).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.49 (+0.14, -0.15).
If the light curve continues to decay with a power-law decay index of
0.49, the count rate at T+24 hours will be 2.0 x 10^-3 count s^-1
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00688452.
This circular is an official product of the Swift-XRT team.
GCN Circular 19488
Subject
GRB160601A: NOT afterglow confirmation
Date
2016-06-02T05:43:55Z (9 years ago)
From
Steve Schulze at U of Iceland <sts30@hi.is>
S. Schulze (PUC, MAS), D. Malesani (DARK/NBI), A. A. Djupvik (NOT) and P. Jakobsson (U Iceland) report on behalf a larger collaboration:
We re-observed the field of the short GRB 160601A (Kocevski et al., GCN 19478) with the Nordic Optical Telescope (NOT) equipped with the AlFOSC imager. Our first 600-s exposure in the r band started on June 1 at 21:14:48 UT (13.5 hr after the GRB).
We cleanly detect the two objects reported in Malesani et al. (GCN 19485).
Object (1) (RA, Dec. = 15:39:43.97, +64:32:30.5) faded from 22.85 +- 0.10 to 23.36 +- 0.10 mag. The fading corresponds to a decay slope of 0.64 +- 0.25.
Object (2) (RA, Dec. = 15:39:44.91, +64:32:32.1) exhibits no variability beyond the 1.7 sigma confidence level.
These properties let us conclude that object (1) is the afterglow of the short GRB.
[GCN OPS NOTE(02jun16): Per author's request, the start time in the first sentence
was corrected from "21:14:48" to "04:15:44".]
GCN Circular 19489
Subject
GRB160601A: Kanata Telescope I- and Ks-bands upper limits
Date
2016-06-02T13:51:17Z (9 years ago)
From
Michitoshi Yoshida at HASC,Hiroshima U <yoshidam@hiroshima-u.ac.jp>
T. Nakaoka, Hirochi, J., Yoshida, M. and Kawabata, K. S. (Hiroshima
Univ.) report on behalf of the OISTER collaboration
We performed I and Ks bands imaging observations around the error
circle of GRB 160601A (Kocevski et al., GCNC 19478) with the optical
infrared simultaneous camera HONIR attached to Kanata telescope of
Hiroshima University. We started the observations at 2016-06-01 16:42
UT. We did not find any optical-infrared counterpart of the burst. Five
sigma upper limits (Vega magnitude) are listed below.
# T0+[day] MID-UT T-EXP(I) T-EXP(Ks) I Ks
-----------------------------------------------------------
0.08249 17:25:14 4025s 3500s >20.6 >17.0
-----------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 19490
Subject
GRB 160601A: Mondy optical observations, photometry of NOT sources
Date
2016-06-02T14:35:18Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev
(ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of the Swift GRB 160601A (Kocevski et al., GCN
19478) with AZT-33IK telescope of Sayan observatory (Mondy) starting on
June, 01 (UT) 15:00:41, i.e. 17 minutes after GRB trigger (GCN 19483).
In a combined image we detected both NOT sources (Malesani et al., GCN
19485) near enhanced XRT error circle (Evans et al., GCN 19484).
Preliminary photometry (Vega) of the sources are following
Date UT start t-T0 Filter Exp. NOT1 NOT2
(mid, days) (s)
2016-06-01 15:00:41 0.04181 R 85*60 22.40+/-0.25 22.10+/-0.20
Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R:
SDSS-DR9_id R(Lupton)
J153959.67+643325.7 16.72
J153956.37+643102.2 17.00
J153931.88+643247.0 17.02
J153927.50+643304.3 19.23
J153942.70+643016.4 16.27
A finding chart can be found at
http://grb.rssi.ru/GRB160601A/GRB160601A_Mondy_160601_NOT_1_2.png
GCN Circular 19491
Subject
GRB 160601A: GTC observations confirming transient source decay
Date
2016-06-02T15:00:10Z (9 years ago)
From
Juan Carlos Tello at IAA-CSIC <jtello@iaa.es>
J. C. Tello, Y. Hu (IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC, ISA-UMA),
S. Oates (Warwick U.), A. Perez-Romero and D. Garcia-Alvarez (GTC-IAC)
on behalf of a larger collaboration, report:
We observed the field of GRB 160601A (Kocevski et al., GCN 19478) with the
Gran Telescopio Canarias (GTC) with the OSIRIS instrument and acquired
6x100s images starting 01:37:31 UT and ending 01:49:29 UT on July 2nd
(10h54m-11h06m after the Swift trigger) and we detect the afterglow
candidates reported by Malesani et al. (GCN 19485).
We also find like Schulze (GCN 19488) that Object 1 is fading and at the
time of our observations was at a magntude of ~ 23.5 in the Sloan_r filter
and calibrated to SDSS Release 6.
We note that our observations precede Schulze's by 2.5 hours and are
slightly fainter but not much more than the uncertainty of these
preliminary results, implying either a rebrightening event or a plateau due
to either afterglow behaviour or host galaxy.
[GCN OPS NOTE903jun16): Per author's request, AP-R and DG-A were added
to the author list.]
GCN Circular 19492
Subject
GRB160601A: Gemini Imaging
Date
2016-06-02T15:06:54Z (9 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko (NASA/GSFC), W.-F. Fong (Arizona), A. J. Levan (Warwick), A. Cucchiara (STScI), E. Berger (Harvard), and D. A Perley (DARK) report on behalf of a larger collaboration:
We imaged the location of GRB160601A (Kocevski et al., GCN 19478) with the Gemini Multi-Object Spectrograph (GMOS) mounted on the 8m Gemini North telescope. We obtained a series of 5 x 180 s r-band images beginning at 6:02 UT on 2016 June 2 (~ 15.3 hr after the BAT trigger). The candidate optical afterglow proposed by Malesani et al (GCN 19485; their Source 1) is confirmed to be fading (see also Schulze et al., GCN 19488, Tello et al., GCN 19491). Using nearby point sources from SDSS for calibration, we measure a magnitude of r = 23.69 +/- 0.05 at this time.
We note that the source appears to be (marginally) extended in our GMOS images, and therefore host contamination may to be present in the above magnitude estimate.
GCN Circular 19494
Subject
GRB 160601A: Swift-BAT refined analysis
Date
2016-06-02T17:50:25Z (9 years ago)
From
Tilan Ukwatta at LANL <tilan.ukwatta@gmail.com>
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),
N. Gehrels (GSFC), D. Kocevski (NASA/GSFC/ORAU),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
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+500 sec from the recent
telemetry downlink, we report further analysis of BAT
GRB 160601A (trigger #688452) (Kocevski, et al., GCN Circ.
19478). The BAT ground-calculated position is
RA, Dec = 234.923, 64.532 deg which is
RA(J2000) = 15h 39m 41.6s
Dec(J2000) = +64d 31' 53.5"
with an uncertainty of 1.9 arcmin, (radius, sys+stat,
90% containment). The partial coding was 66%.
The mask-weighted light curve shows a single pluse
starting ~T-0.1 sec, and ending around ~T+0.15 sec.
T90 (15-350 keV) is 0.12 +- 0.02 sec (estimated error
including systematics).
The time-averaged spectrum from T-0.02 to T+0.12 sec is
best fit by a simple power-law model. The power law
index of the time-averaged spectrum is 1.04 +- 0.24.
The fluence in the 15-150 keV band is 6.6 +- 1.1 x 10^-08
erg/cm2. The 1-sec peak photon flux measured from T-0.45
sec in the 15-150 keV band is 0.9 +- 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/688452/BA/
GCN Circular 19495
Subject
GRB 160601A: MITSuME Akeno optical upper limits
Date
2016-06-03T06:44:27Z (9 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
Y. Saito, Y. Tachibana, T. Yoshii, T. Fujiwara, Y. Ono, Y. Muraki, S. Harita,
T, Ozawa, K. Saisho, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 160601A (D. Kocevski et al., GCN Circular #19478)
with theoptical three color (g', Rc, and Ic) CCD cameras attached to the
MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2016-06-01 23:43:35 UT (33 sec after the burst).
We did not find any new point source within XRT circle in all three bands.
We obtained following limits for the magnitudes.
T0+[day] MID-UT T-EXP[sec] g' Rc Ic
------------------------------------------------------------------------------------------
0.078 16:35:35 12060 >21.7 >21.1 >19.9
------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst.
T-EXP: Total Exposure time.
We used GSC2.3 catalog for flux calibration.
GCN Circular 19496
Subject
GRB 160601A: Swift/UVOT Upper Limits
Date
2016-06-03T15:28:24Z (9 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
S. Sebzda (Penn State/Swift) and D. Kocevski (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160601A
78 s after the BAT trigger (Kocevski et al., GCN Circ. 19478).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 19484) 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
white (fc) 78 227 147 >21.00
white 78 589 166 >20.90
v 619 639 19 >17.30
b 544 564 19 >18.32
u (fc) 289 539 491 >20.19
uvw1 668 688 19 >17.72
uvm2 643 663 19 >17.46
uvw2 595 615 19 >17.87
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 19497
Subject
GRB 160601A: Discovery Channel Telescope Limits
Date
2016-06-03T17:32:35Z (9 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko and E. Troja (NASA/GSFC) report on behalf of a larger collaboration:
We imaged the location of the optical afterglow (Malesani et al., GCN 19485) of the short GRB 160601A (Kocevski et al., GCN 19478) with the Large Monolithic Imager on the 4.3-m Discovery Channel Telescope in Happy Jack, AZ. We obtained a series of 180 s exposures in the r-band filter beginning at 5:00 UT on 2016 June 3 (~ 1.6 d after the Swift trigger). We do not detect any significant emission at the location of the optical afterglow to a limiting magnitude of r > 25.0 (calculated with respect to nearby point sources from SDSS). Compared to the most recent detection with Gemini (Cenko et al, GCN 19492), our limits imply a significant steepening of the afterglow decay, with a lower limit on the power-law index of alpha > 1.3 (compared to alpha ~ 0.6 at earlier times; Schulze et al. 19488).
We thank the observers (T. Farnham, M. Knight, and L. Feagan) and the DCT staff for their assistance with these observations.
GCN Circular 19498
Subject
GRB 160601A: AbAO optical observations
Date
2016-06-03T18:19:24Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Volnova (IKI), R. Inasaridze (AbAO), V. Ayvazian
(AbAO), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger
GRB follow-up collaboration:
We observed the field of of the Swift GRB 160601A (Kocevski et al., GCN
19478) with AS-32 (0.7m) telescope of Abastumani Observatory starting on
June, 01 (UT) 19:07:28. We obtained several unfiltered images of the
field. In a combined image we detected both NOT sources (Malesani et
al., GCN 19485). Preliminary photometry of the optical afterglow (NOT
source #1, Schulze et al., GCN 19488) are following
Date UT start t-T0 Filter Exp. OT UpLim (3 sigma)
(mid, days) (s)
2016-06-01 19:07:28 0.20169 CR 26*120 22.9+/-0.3 23.0
Photometry is based on nearby SDSS-DR9 stars, Lupton transformations
into R:
SDSS-DR9_id R(Lupton)
J153959.67+643325.7 16.72
J153956.37+643102.2 17.00
J153931.88+643247.0 17.02
J153927.50+643304.3 19.23
J153942.70+643016.4 16.27
J153948.64+643150.1 19.27
J153948.72+643220.0 19.86
GCN Circular 19608
Subject
GRB 160601A: 15 GHz upper limits from AMI
Date
2016-06-28T13:09:02Z (9 years ago)
From
Kunal Mooley at Oxford U <kunal.mooley@physics.ox.ac.uk>
K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S.
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge),
K. Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for GRB
160601A (Kocevski et al., GCN 19478) as part of the 4pisky program, and
subsequent follow up observations were obtained up to 10 days
post-burst. Our observations at 15 GHz on 2016 Jun 01.78, Jun 02.95, Jun
04.95, and Jun 11.95 (UT) do not reveal any radio source at the XRT
location (Evans et al., GCN 19484), with 3sigma upper limits of 282 uJy,
216 uJy, 108 uJy, and 132 uJy respectively.
We thank the AMI staff for scheduling these observations. The AMI-GRB
database is a log of all GRB follow up observations with the AMI, and is
available at http://4pisky.org/ami-grb/.