GRB 170710B

D. M. Palmer (LANL) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift Team:

At 08:10:06.251 UT on 2017-07-10, the Swift Burst Alert Telescope (BAT)
detected a GRB during a pre-planned slew to a scheduled target.
Ground analysis using data from T-25 to T+79 s finds the source at a
location of
RA, Dec = 43.122, 42.679 deg which is
  RA(J2000)  =  02h 52m 29.3s
  Dec(J2000) = +42d 40' 43.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).

The mask-weighted light curve shows a single FRED-like pulse that starts
and peaks at ~T0, and ends at ~T+60 s. T90 (15-350 keV) is 54.4 +- 1.6 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.0 to T+59.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.38 +- 0.08.  The fluence in the 15-150 keV band is 2.4 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+5.10 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.

This GRB also triggered Fermi/GBM (GBM trigger# 521367012).

A Swift Target of Opportunity observation has been requested.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/00086619001/BA/

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a ToO observation of the Fermi/GBM GRB 170710B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020777

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 Fermi/GBM 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.

K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N.
Burrows (PSU), A. Cholden-Brown (PSU), B. Mingo (U. Leicester), A.P.
Beardmore (U. Leicester), A.A. Breeveld (MSSL/UCL), S.B. Cenko (GSFC)
and P.A. Evans (U. Leicester) report on behalf of the Swift team:

Swift has performed follow-up observations of the BAT and
Fermi/GBM-detected burst GRB 170710B (Palmer & Lien, GCN Circ. 21316
Loading...
 
 ),
collecting 4.0 ks of Photon Counting (PC) mode data between T0+85.2 ks
and T0+92.7 ks. 

One uncatalogued X-ray source has been detected consistent with being
within 296 arcsec of the BAT position; it is below the RASS limit and
shows no definitive signs of fading. It is 4.8" from SDSS
J025227.08+423819.4, which is a possible quasar, therefore more data
are needed to confirm whether the XRT source is the GRB afterglow.
Further observations are planned. Details of this source are given
below:

Source 1:
  RA (J2000.0):  43.1110  =  02:52:26.65
  Dec (J2000.0): +42.6391  =  +42:38:20.7
  Error: 3.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (6.4 [+1.6, -1.4])e-3 ct s^-1   
  Distance: 146 arcsec from BAT position.
  Flux: (2.51 [+0.61, -0.56])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


The UVOT started observing this source 85.2 ks after the burst. The
catalogued source just on the edge of the XRT region is detected, but
no new source is found to an upper limit in the UVW2 filter of 21.3 mag
in 3924s of exposure.

Two uncatalogued X-ray sources were also detected too far from the GRB
position to be likely afterglow candidates.

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/00020777.

This circular is an official product of the Swift2 team.

R. Hamburg (UAH), C. Meegan (UAH), and E. Bissaldi (Politecnico & INFN
Bari):
report on behalf of the Fermi GBM Team:

"At 08:10:08.00 UT on 10 July 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170710B (trigger 521367012 / 170710340)
which was also detected by the Swift/BAT
(D. Palmer et al. 2017, GCN  21316
Loading...
 
 )
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 49
degrees.

The GBM light curve consists of one main peak
with a duration (T90) of about 42 s (50-300 keV).
The time-averaged spectrum from T0-4 s to T0+28 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.2 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 293 +/- 61 keV.
A Band function fits the spectrum equally well
with Epeak= 149 +/- 49 keV, alpha = -0.9 +/- 0.2 and beta = -1.9 +/- 0.2.

The event fluence (10-1000 keV) in this time interval is
(6.0 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.5 s in the 10-1000 keV band
is 2.7 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

K.L. Page and P.A. Evans (U. Leicester) report on behalf of the Swift
team:

Swift performed a further observation of the field of the BAT and
Fermi/GBM-detected burst GRB 170710B (Palmer & Lien, GCN Circ. 21316
Loading...
 
 ;
Hamburg, Meegan & Bissaldi, GCN Circ. 21319
Loading...
 
 ) on 2017 July 15. The
XRT-detected "Source 1", as given in Page et al. (GCN Circ. 21318
Loading...
 
 ), shows
no sign of fading, with a count rate of (5.6 +1.9/-1.5)x10^-3 count s^-1
compared to (6.4 +/- 1.5)x10^-3 count s^-1 from the first observation on
July 11. This is therefore not the GRB afterglow.

This circular is an official product of the Swift-XRT team.

K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender 
(Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. 
Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, 
P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)

The AMI Large Array triggered on the Swift alert for GRB 170710B (Palmer 
et al., GCN 21316
Loading...
 
 ) 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 Jul 12.3, Jul 13.26, Jul 15.29 and Jul 19.23 (UT) do 
not reveal any radio source at the BAT location (Palmer et al., GCN 
21316
Loading...
 
 ), with 3sigma upper limits of 153 uJy, 93 uJy, 93 uJy and 222 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/.