GRB 170604A
GCN Circular 21191
Subject
GRB 170604A: Swift detection of a burst
Date
2017-06-04T19:29:03Z (8 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
K. L. Page (U Leicester), A. Cholden-Brown (PSU),
N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC) and
F. E. Marshall (NASA/GSFC) report on behalf of the Swift Team:
At 19:08:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170604A (trigger=755867). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 342.645, -15.414 which is
RA(J2000) = 22h 50m 35s
Dec(J2000) = -15d 24' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 25 sec. The peak count rate
was ~2400 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 19:10:55.1 UT, 124.7 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. However, the XRT TDRSS light curve suggests the presence of a bright,
fading source; since no Photon Counting mode data were collected, no prompt
source localisation can be performed. We are waiting for the full dataset to
detect and localise the XRT counterpart.
No results from UVOT are available at this time.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk).
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 21192
Subject
GRB 170604A: optical observations
Date
2017-06-04T20:17:53Z (8 years ago)
From
Luca Izzo at IAA-CSIC <Luca.Izzo@ICRA.it>
L. Izzo, A. de Ugarte Postigo, Z. Cano, D.A. Kann (IAA-CSIC) report on behalf of a larger collaboration,
We observed the field of GRB 170604A (Page et al., GCN 21191) with the T27 (Plane Wave CDK 0.70m) of the iTelescope.Net (http://www.itelescope.net) located at Siding Spring, AU.
A single image of 300 s each was taken in the R and in the V filters, starting at 19:32:07 UT, ~ 1400s after the GRB trigger. We detect a source not visible in PanSTARRS images at RA = 22:50:37.54 DEC = -15:24:44.4 (+- 0.5���) with a preliminary magnitude of R ~ 17.5 (as compared to USNO-B 1.0 field stars), which we consider to be the afterglow.
An image of the field can be seen at http://goo.gl/Rjmsk6
GCN Circular 21195
Subject
GRB 170604A: Swift-BAT refined analysis
Date
2017-06-05T02:19:40Z (8 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. Sakamoto (AGU), 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 170604A (trigger #755867)
(Page et al., GCN Circ. 21191). The BAT ground-calculated position is
RA, Dec = 342.645, -15.406 deg which is
RA(J2000) = 22h 50m 34.9s
Dec(J2000) = -15d 24' 20.1"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 8%.
The mask-weighted light curve shows several overlapping pulses that start
at ~ T-12 s and end at ~T+20 s. The main peak occurs at ~T+3 s.
T90 (15-350 keV) is 26.70 +- 6.21 sec (estimated error including systematics).
The time-averaged spectrum from T-11.66 to T+22.58 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.31 +- 0.12. The fluence in the 15-150 keV band is 5.1 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+2.66 sec in the 15-150 keV band
is 4.2 +- 0.9 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/755867/BA/
GCN Circular 21196
Subject
GRB 170604A: Enhanced Swift-XRT position
Date
2017-06-05T08:03:35Z (8 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
K.L. Page, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the
Swift-XRT team:
Using 4539 s of XRT Photon Counting mode data and 10 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 =
342.65623, -15.41233 which is equivalent to:
RA (J2000): 22 50 37.49
Dec (J2000): -15 24 44.4
with an uncertainty of 1.4 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 21197
Subject
GRB 170604A: GTC spectroscopic redshift
Date
2017-06-05T08:04:01Z (8 years ago)
From
Zach Cano at U of Iceland <zewcano@gmail.com>
L. Izzo, Z. Cano (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D.
A. Kann (IAA-CSIC), C. C. Thoene (IAA-CSIC), A. Marante (GTC) and S. Geier
(GTC, IAC) report on behalf of a larger collaboration:
We observed the afterglow of GRB 170604A (Page et al., GCN Circ. 21191)
using OSIRIS at the 10.4 m GTC telescope at La Palma (Spain). The
observation consisted of 2x900s and 1x1200s exposures using the R1000B
grism, which covers a wavelength range of 3700-7880 AA. Observations began
at 04:14:19 UT on the morning of 05 June, 2017, at a mean epoch of +9.51
hrs from the GRB detection. The afterglow candidate (Izzo et al, GCN Circ.
21192) is detected in the r-band acquisition image, where we measure r =
20.3 +- 0.1 relative to nearby PANSTARRS standards in the GRB field of
view.
The afterglow spectrum shows a continuum through the observed wavelength
range, and we identify absorption features corresponding to MgII, MgI, and
FeII at a common redshift of z=1.329, which we identify as the redshift of
GRB 170604A.
GCN Circular 21198
Subject
GRB 170604A: Swift-XRT refined Analysis
Date
2017-06-05T08:21:54Z (8 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Cholden-Brown
(PSU), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P.A.
Evans (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB) and K.L. Page report on behalf of the Swift-XRT
team:
We have analysed 7.6 ks of XRT data for GRB 170604A (Page et al. GCN
Circ. 21191), from 110 s to 39.1 ks after the BAT trigger. The data
comprise 308 s in Windowed Timing (WT) mode (the first 7 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. Using 4539 s of PC mode data and 10 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 = 342.65623, -15.41233
which is equivalent to:
RA (J2000): 22h 50m 37.49s
Dec(J2000): -15d 24' 44.4"
with an uncertainty of 1.4 arcsec (radius, 90% confidence).
The late-time light curve (from T0+3.8 ks) can be modelled with a
power-law decay with a decay index of alpha=0.98 (+/-0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.27 (+/-0.04). The
best-fitting absorption column is 1.95 (+/-0.11) x 10^21 cm^-2, in
excess of the Galactic value of 3.8 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.85 (+/-0.09) and a
best-fitting absorption column of 6.9 (+2.3, -2.2) x 10^20 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.6 x 10^-11 (4.0 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.9 (+2.3, -2.2) x 10^20 cm^-2
Galactic foreground: 3.8 x 10^20 cm^-2
Excess significance: 2.3 sigma
Photon index: 1.85 (+/-0.09)
If the light curve continues to decay with a power-law decay index of
0.98, the count rate at T+24 hours will be 0.046 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.6 x
10^-12 (1.9 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00755867.
This circular is an official product of the Swift-XRT team.
GCN Circular 21200
Subject
GROND observations of GRB170604A
Date
2017-06-05T11:20:22Z (8 years ago)
From
Patricia Schady at MPE/Swift <pschady@mpe.mpg.de>
P. Schady (MPE) reports:
We observed the field of GRB 170604A (Swift trigger 755867; Page et al.,
GCN #21191) 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 06:15 UT on 05-06-2017, 11.1 hours the GRB
trigger. They were performed at an average seeing of 1.3" and at an
average airmass
of 2.
We detect a point source within the 1.4" enhanced Swift/XRT error circle
(Page et al., GCN 21196), and consistent with the afterglow position
reported by Izzo et al. (GCN #21192).
Based on a total exposure of 4.6 min in g'r'i'z' and 4 min in JHK, we
estimate preliminary magnitudes (all in AB) of
g' = 20.75 +/- 0.08
r' = 20.46 +/- 0.05
i' = 20.35 +/- 0.06
z' = 20.21 +/- 0.08
J = 19.6 +/- 0.1
H = 19.6 +/- 0.3
K > 19.6
Given magnitudes are calibrated against PanSTARRS and 2MASS field stars
and are not corrected for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the
burst (Schlafly & Finkbeiner 2011).
We acknowledge the excellent support provided by Simona Ciceri in
obtaining these data.
GCN Circular 21203
Subject
GRB 170604A: AbAO optical observations
Date
2017-06-05T15:48:31Z (8 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), R. Inasaridze (AbAO), A. Pozanenko (IKI), A. Volnova
(IKI), V. Ayvazian (AbAO), O. Kvaratskhelia (AbAO), G. Inasaridze
(AbAO), I. Molotov (KIAM), report on behalf of larger GRB follow-up
collaboration:
We observed the field of the Swift GRB 170604A (Page et al., GCN 21191)
with AS-32 (0.7m) telescope of Abastumani Observatory starting on
June, 04 (UT) 23:52:07. We obtained several unfiltered images of the
field. Within enhanced XRT error circle (Page et al., GCN 21196) we
detected the afterglow (Izzo et al, GCN 21192; Izzo et al, GCN 21197;
Schady, , GCN 21200). Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err UpLim (3 sigma)
(mid, days) (s)
2017-06-04 23:52:07 0.19950 CR 5*60 19.13 0.18 21.0
2017-06-05 00:00:50 0.20675 CR 7*60 19.23 0.16 21.1
2017-06-05 00:13:02 0.21885 CR 13*60 19.30 0.22 20.6
Photometry is based on nearby USNO-B1.0 stars (R2 magnitudes)
USNO-B.1_id R2
0746-0830331 14.71
0746-0830367 14.76
0746-0830438 15.14
0746-0830455 14.77
0747-0821123 14.60
[GCN OPS NOTE(05jun17): Per author's request, the duplicate text
of this circular was removed.]
GCN Circular 21204
Subject
GRB 170604A: RATIR Optical and NIR Observations
Date
2017-06-05T16:48:58Z (8 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 170604A (Page, et al., GCN 21191) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2017/06 5.39 to 2017/06 5.45 UTC (14.19 to
15.70 hours after the BAT trigger), obtaining a total of 0.84 hours
exposure in the r and i bands and 0.42 hours exposure in the Z and Y bands.
For a source within the Swift-XRT error circle (Page, et al., GCN 21196),
in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following
detections:
r = 20.42 +/- 0.06
i = 20.65 +/- 0.07
Z = 20.45 +/- 0.13
Y = 20.40 +/- 0.30
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 Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 21207
Subject
GRB 170604A: Swift/UVOT Observations
Date
2017-06-05T19:10:10Z (8 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170604A
128 s after the BAT trigger (Page et al., GCN Circ. 21191).
We detect a fading afterglow consistent with the position given by XRT
(Page et al., GCN Circ 21196) and ground-based optical detections
(Izzy et al., GCN Circ 21197; Schady, GCN Circ. 21200; Mazaeva et al.,
GCN Circ 21203).
The preliminary UVOT position is:
RA (J2000) = 22:50:37.52 = 342.65632 (deg.)
Dec (J2000) = -15:24:43.9 = -15.41220 (deg.)
with an estimated uncertainty of 0.1 arc sec. (radius, 90% confidence).
Preliminary magnitudes and 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) 128 278 147 15.81+-0.03
white 3968 5603 393 18.72+-0.06
white 39053 39959 885 20.57+-0.18
v 4378 6013 393 18.94+-0.31
v 34480 44756 1268 >19.89
b 3763 5398 393 19.26+-0.15
b 38141 39048 885 >20.86
u (fc) 287 429 279 15.70+-0.03
u 4993 5193 196 18.51+-0.16
u 28543 29132 576 >19.72
uvw1 4788 4988 196 18.47+-0.19
uvw1 23318 46354 1633 20.20+-0.27
uvm2 4583 6169 344 18.58+-0.18
uvm2 44762 45661 885 >20.37
uvw2 4174 5809 393 19.53+-0.26
uvw2 32392 40613 1700 >20.86
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 21247
Subject
Konus-Wind observation of GRB 170604A
Date
2017-06-11T15:27:18Z (8 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 170604A (Swift-BAT trigger #736407: Page et al.,
GCN 21191; Stamatikos et al., GCN 21195; T0(BAT)=17:08:50.402 UT)
was detected by Konus-Wind (KW) in the waiting mode.
The light curve shows a single peak with a duration of ~30 s.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)-16.155 s to T0(BAT)+10.341 s) by
a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.31(-0.20,+0.26) and Ep = 220(-48,+72) keV.
The energy fluence for this time interval is (1.03 �� 0.13)x10^-5
erg/cm2, and the peak energy flux, measured on a 2.944 s scale from
T0(BAT)+1.509 s is (6.9 �� 0.13)x10^-7 erg/cm2/s, both in the
20 keV-10 MeV range.
Assuming the redshift z=1.329 (Izzo et al., GCN 21197)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.30, and Omega_Lambda = 0.70, we estimate the burst
isotropic energy release E_iso to (4.7 �� 0.6)x10^52 erg,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,z, to 512(-112,+168) keV.
The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB170604A/
All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.