Gamma-ray Burst 171010A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 11 Oct 17 00:06:01 UT
NOTICE_TYPE:     Fermi-LAT Offline Position
TRIGGER_NUM:     171010792 
GRB_RA:           66.740d {+04h 26m 58s} (J2000),
                  66.951d {+04h 27m 48s} (current),
                  66.147d {+04h 24m 35s} (1950)
GRB_DEC:         -10.540d {-10d 32' 23"} (J2000),
                 -10.501d {-10d 30' 03"} (current),
                 -10.651d {-10d 39' 03"} (1950)
GRB_ERROR:       14.39 [arcmin radius, 90% containment, statistical only]
GRB_DATE:        18036 TJD;   283 DOY;   17/10/10
GRB_TIME:        68450.58 SOD {19:00:50.58} UT
TRIGGER_ID:      0x0
MISC:            0x40000000
SUN_POSTN:       196.48d {+13h 05m 56s}   -7.01d {-07d 00' 40"}
SUN_DIST:        126.79 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:       87.64d {+05h 50m 33s}  +19.19d {+19d 11' 23"}  
MOON_DIST:        36.02 [deg] 
MOON_ILLUM:      67 [%] 
GAL_COORDS:      205.65,-36.81 [deg] galactic lon,lat of the burst (or transient)      
ECL_COORDS:       62.82,-31.81 [deg] ecliptic lon,lat of the burst (or transient)       
COMMENTS:        Fermi LAT Offline position.
COMMENTS:        This Notice was ground-generated -- not flight-generated.
COMMENTS:        It is the result of human-in-the-loop processing.
COMMENTS:        This is a human generated position of a LAT ground detection.
COMMENTS:        This source corresponds to GBM trigger.

GCN Circular #21985
N. Omodei (Stanford U.), G. Vianello (Stanford U.), B. Ahlgren (KTH)
report on behalf of the Fermi-LAT team:
At 19:00:50.58 on October, 10, 2017 Fermi-LAT detected high-energy emission from GRB 171010A, which was also detected by Fermi-GBM (trigger 529354855 / 171010792).
The best LAT on-ground location is found to be:
RA, Dec = 66.74, -10.53 (J2000)
with an error radius of 0.20 deg (90 % containment, statistical error only).
The GRB was outside the LAT field of view at the time of the GBM trigger and triggered an autonomous repoint of the spacecraft.
The data from the Fermi-LAT show a significant increase in the event rate that is spatially correlated with the trigger with high significance.
The highest-energy photon is a 7 GeV event which is observed 768 seconds after the GBM trigger.
A Swift ToO has been requested for this burst.
The Fermi-LAT point of contact for this burst is B. Ahlgren (bjornah@kth.se).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular #21986
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/LAT GRB 171010A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020778
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/LAT 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.
GCN Circular #21987
John R. Thorstensen (Dartmouth) and Jules P. Halpern (Columbia) report:
Automated analysis of Swift XRT data (GCN #21986) on Fermi-LAT GRB 171010A (GCN #21985) reports a fading X-ray source at:
(J2000.0) 04:26:19.44 -10:27:47.1 +/- 1.4"
We pointed the 1.3m McGraw-Hill telescope of the MDM Observatory at this location beginning on 2017 October 11 08:31 UT, 13.5 hr after the burst, and obtained images in the Cousins R filter that show a new object at:
(J2000.0) 04:26:19.48 -10:27:46.2 +/- 0.4"
with position referenced to the PPMXL catalog. In comparison with nearby stars with r magnitudes from Pan-STARRS, we estimate r = 18.0 at 08:31 UT. Continuing photometry shows that the OT faded from r = 18.05 to 18.38 between 8:55 UT and 10:28 UT.
There is also a faint galaxy at this position on the digitized POSS II and in Pan-STARRS, but bright moon now makes it difficult to detect in our images. The Pan-STARRS position of this possible host galaxy is:
(J2000.0) 04:26:19.56 -10:27:45.8
Using the 2.4m Hiltner telescope with Modspec, we obtained 17x12 minutes spectra of the OT covering the wavelength range 4400-7500 A at 4 A resolution, which when summed show a featureless continuum with a signal-to-noise ratio of about 50 per 2 A pixel.
GCN Circular #21988
L. Izzo (IAA-CSIC) and D. Malesani (DARK/NBI) report:
We observed the field of the Fermi LAT GRB 171010A (Omodei et al., GCN 21985) with the T24 (Plane Wave CDK 0.61m) of the iTelescope.Net <http://itelescope.net/> (http://www.itelescope.net
) located at Auberry (CA, USA).
A set of three images of 300 s each was taken in the I filter, starting on October 11th at 09:55:32 UT, ~14.9 hr after the LAT GRB trigger. In particular, we inspected the position of the X-ray candidate found by XRT (Evans, GCN 21986), reported at http://www.swift.ac.uk/ToO_GRBs/00020778
. Inside the UVOT-enhanced XRT position, we detect a source at coordinates (J2000):
```
RA = 04:26:19.46
DEC = -10:27:45.9
```
This position is 1.3" W of an object with i = 20.31 +- 0.05 (AB) visible in the Pan-STARRS archival images. We measure for the source I = 17.85 +- 0.20 mag (AB)
The difference in brightness with respect to the archival Pan-STARRS source, as well as the association with the XRT counterpart, suggests the presence of an additional source which we believe to be due to the GRB afterglow. The Pan-STARRS object could be the host galaxy of the GRB, as also suggested in Thorstensen et al. (GCN 21987), or an unrelated source.
Additional observations are very welcome.
GCN Circular #21989
A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the Fermi/LAT-detected burst GRB 171010A (Omodei et al. GCN Circ. 21985), collecting 5.0 ks of Photon Counting (PC) mode data between T0+24.2 ks and T0+41.7 ks.
Four uncatalogued X-ray sources are detected, of which one ("Source 2") is above the RASS limit, and is therefore likely the GRB afterglow. Using 4537 s of PC mode data and 7 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 = 66.58092, -10.46325 which is equivalent to:
```
RA (J2000): 04h 26m 19.42s
Dec(J2000): -10d 27' 47.7"
```
with an uncertainty of 1.4 arcsec (radius, 90% confidence). This position is 10.5 arcmin from the Fermi/LAT position.
The light curve can be modelled with a power-law decay with a decay index of alpha=2.2 (+/-0.3).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.01 (+/-0.15). The best-fitting absorption column is 3.6 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 7.0 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.6 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 7.0 x 10^20 cm^-2
Excess significance: 7.4 sigma
Photon index:	     2.01 (+/-0.15)
```
If the light curve continues to decay with a power-law decay index of 2.2, the count rate at T+24 hours will be 0.054 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x 10^-12 (2.7 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/00020778. The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00020778.
This circular is an official product of the Swift-XRT team.
GCN Circular #21990
V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:
Analysis of Astrosat CZTI data showed the detection of a long-duration bright GRB 171010A, which was also detected by Fermi-GBM (trigger 529354855 / 171010792) and Fermi-LAT (Omodei N. et al, GCN # 21985).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peak emission with strongest peak at 19:01:24.58 UT, ~34 s after the Fermi Trigger. The measured peak count rate is 2001.9 cts/s above the background in combined data of four quadrants, with a total of 61101 cts. The local mean background count rate was 333.1 cts/s. Using cumulative rates, we measure a T90 of 70.3 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular #21991
C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath),=20 A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a large=20 collaboration report:
We began observing Fermi LAT GRB 171010A (Omodei et al. GCN 21985) on=20 October 11, from 02:15 to 02:28 UT (7.2 hours since the GRB trigger=20 time) with one of the 1-m LCO telescopes in Sutherland in the SDSS-I=20 filter. Within the enhanced Swift-XRT circle (D'Ai et al. GCN 21989) we=20 clearly detect the optical afterglow (Thorstensen and Halpern, GCN=20 21987; Izzo and Malesani, GCN 21988) with the following magnitude:
```
Mid Time=A0=A0=A0=A0=A0 Exposure=A0=A0=A0=A0=A0=A0 Filter=A0=A0=A0=A0=A0=A0=
 Magnitude (AB)
(hrs)=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (s)
-------------------------------------------------------
7.3=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 5x120=A0=A0=A0=A0=A0=A0=A0=A0 SDSS-I=
=A0=A0=A0=A0=A0=A0 16.82 +- 0.02
-------------------------------------------------------
```
as calibrated against nearby Pan-STARRS objects.
GCN Circular #21992
S. Poolakkil and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 19:00:50.58 UT on 10 October 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 171010A (trigger 529354855 / 171010792) which was also detected by Fermi LAT (N. Omodei et al. 2017, GCN 21985) and AstroSat (Sharma et al, GCN 21990). The afterglow was observed by Swift-XRT (A. D'Ai et al. 2017, GCN 21989). The GBM on-ground location is consistent with the LAT position.
The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM Flight Software owing to the high peak flux of the GRB. This ARR was accepted and the spacecraft slewed to the GBM in-flight location. The initial angle from the Fermi LAT boresight to the best location is 113 degrees.
The GBM light curve consists of several episodes with a duration (T90) of about 104 s (50-300 keV). The time-averaged spectrum from T0+5.12 s to T0+151.55 s is best fit by a Band function with Epeak = 154 +/- 1 keV, alpha = -1.11 +/- 0.01 and beta = -2.22 +/- 0.01.
The event fluence (10-1000 keV) in this time interval is 6.42E-04 +/- 1.5E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+68.16 s in the 10-1000 keV band is 117.5 +/- 1.02 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #22000
D. Malesani (DARK/NBI), K. E. Heintz (Univ. Iceland and DARK/NBI), P. Calissendorff (Stockholm Univ), and I. R. Losada (NOT) report on behalf of a larger collaboration:
We observed the optical counterpart (Thorstensen & Halpern, GCN 21987; Izzo & Malesani, GCN 21988; Guidorzi et al., GCN 21991) of the Fermi GRB 171010A (Poolakkil & Meegan, GCN 21992; Omodei et al., GCN 21985) with the Nordic Optical Telescope equipped with the StanCam imager. Observations were carried out in the Johnson-Cousins BVRI filters.
The optical counterpart is well detected in our images. Using the Pan-STARRS catalog as reference, we measure a magnitude r = 19.18 +- 0.06 AB at an epoch Oct 12.03 UT (29.74 hr after the trigger).
Comparing our measurement with the report by Thorstensen & Halpern (GCN 21987) we infer a decay index alpha = 1.4 assuming an unbroken power-law decay.
GCN Circular #22001
S. Harita, R. Itoh, K. L. Muarata, Y. Tachibana, T. Yoshii, K. Morita, T. Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We have been observing the optical counterpart of GRB 171010A (N. Omodei et al., GCN Circular #21985) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2017-10-11 13:29:52.24 UT. We detected the previously reported optical afterglow (Thorstensen & Halpern, GCN Circular #21987; Izzo & Malesani, GCN Circular #21988; Guidorzi et al., GCN Circular #21991; Malesani et al., GCN Circular #22000) in Ic and Rc bands. The measured magnitudes were listed as follows.
```
T0+[hour]    MID-UT      T-EXP[sec]         g'              Rc
       Ic
-------------------------------------------------------------------------------------------------------
~18.29         15:23:32          4380           >18.8    18.04+/- 0.16
 17.331 +/- 0.12
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
```
GCN Circular #22002
E. Kankare (QUB), D. O'Neill (QUB), L. Izzo (IAA-CSIC), V. D'Elia (ASI/AS= DC), S. D. Vergani (GEPI/Obs. Paris),=20 D. Malesani (DARK/NBI), K. E. Heintz (Univ. Iceland & DARK/NBI), P. Schad= y (MPE), A. Melandri, P. D'Avanzo,=20 S. Campana, S. Covino (INAF-OAB), M. Magee (QUB), T.-W Chen (MPE), L. Gal= bany (U. Pittsburgh), C. Inserra=20 (Southampton), K. Maguire (QUB), S. Smartt (QUB), O. Yaron (Weizmann), D.= Young (QUB), I. Manulis (Weizmann) report:
We observed the optical afterglow of GRB 171010A (Thorstensen & Halpern, = GCN 21987; Izzo & Malesani,=20 GCN 21988; Guidorzi et al., GCN 21991; Malesani et al. GCN 22000; Harita = et al. GCN 22001) under the=20 extended Public ESO Spectroscopic Survey for Transient Objects (ePESSTO; = see Smartt et al. 2015, A&A,=20 579, 40 http://www.pessto.org ). The observation= s were performed on the ESO New Technology Telescope=20 at La Silla with the EFOSC2 instrument in spectroscopic mode starting fro= m 2017-10-12 at 07:05:01 UT=20 (i.e. 36.1 hours from the burst) and using the Grism 13 (3985-9315 AA, 18= AA resolution). Both the optical=20 afterglow and the object visible in the Pan-STARRS archival images lying = 1.3=E2=80=9D away (suggested as the=20 possible host galaxy by Thorstensen & Halpern, GCN 21987 and Izzo & Males= ani, GCN 21988) were included in the slit.
In the acquisition image, the optical afterglow is clearly detected with a magnitude of R(AB)~19.3.
The optical spectrum shows emission features which we identify as [O II], Hbeta, [O III], and Halpha at a common redshift z=0.33. No clear absorption features are detected, in agreement with the report by Thorstensen & Halpern (GCN 21987). The lack of detection of absorption features in high-S/N spectra is strongly suggestive of a low redshift for the afterglow. Combined with the proximity to the archival object,=20 we suggest that z = 0.33 is the redshift of GRB 171010A. Further analysis is in progress.
GCN Circular #22003
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, very bright GRB 170409A (Fermi-LAT detection: Omodei et al., GCN 21985; Fermi-GBM detection: Poolakkil and Meegan, GCN 21992) triggered Konus-Wind at T0=3D68460.142 s UT (19:01:00.142)
The burst light curve shows a bright, multi-peaked pulse, with a total duration of ~155 s (from ~T0-8 s -- ~T0+147 s), which was preceded by a weaker emission starting from ~T0-150 s. A much weaker pulse is also seen in the KW light curve around ~T0+250 s. The emission is seen up to ~15 MeV.
As observed by Konus-Wind, the burst had a fluence of (6.5 =B1 0.2)x10^-4 erg/cm2 and a 64-ms peak energy flux, measured from T0+26.496, of (2.45 =B1 0.17)x10^-5 erg/cm2 (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+147.968 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -1.09 (-0.04,+0.04), the high energy photon index beta =3D -2.42 (-0.07,+0.06), the peak energy Ep =3D 171 (-6,+7) keV, chi2 =3D 95/95 dof.
The spectrum near the peak count rate (measured from T0+26.112 s to T0+27.136 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -0.75 (-0.06,+0.06), the high energy photon index beta =3D -2.58 (-0.22,+0.16), the peak energy Ep =3D 273 (-27,+27) keV, chi2 =3D 78/70 dof.
Assuming the redshift z=3D0.33 (Kankare et al., GCN 22002) and a standard cosmology model with H_0 =3D 70 km/s/Mpc, Omega_M =3D 0.3, and Omega_Lambda =3D 0.7, we estimate the following rest-frame parameters: the isotropic energy release E_iso is ~1.8x10^53 erg, the peak luminosity L_iso is ~8.8x10^51 erg/s, and the rest-frame peak energy of the time-integrated spectrum, Ep,i, is ~227 keV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB171010_T68460/
All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.
GCN Circular #22004
A. A. Breeveld (UCL-MSSL) and M. H. Siegel (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 171010A 69338 s after the LAT trigger (Omodei et al., GCN Circ. 21985). A afterglow (Thorstensen and Halpern, GCN Circ. 21987, Izzo and=20 Malesani, GCN Circ. 21988, Guidorzi et al., GCN Circ. 21991, Malesani et al., GCN Circ. 22000, Harita et al., GCN Circ. 22001) is detected in the initial UVOT exposures. However it is not possible to distinguish this source from the position of the Pan-STARRS source given in Izzo and Malesani (GCN Circ. 21988). The source magnitude is not changing significantly within this observation.
Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the summed exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white            69338        80991         4818         18.84 =B1 0.02
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) =3D 0.15 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #22011
Alan M. Watson (UNAM), Eleonora Troja (GSFC), 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 (UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
We observed the field of GRB 171010A (Omodei et al., GCN Circ. 21985) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2017/10 13.33 to 2017/10 13.50 UTC (60.79 to 65.05 hours after the LAT trigger), obtaining a total of 2.72 hours exposure in the r and i bands and 1.13 hours exposure in the Z, Y, J, and H bands.
We detect the afterglow candidate reported by Thorstensen & Halpern (GCN Circ. 21987), Izzo & Malesani (GCN Circ. 21988), and D'Ai et al. (GCN Circ. 21989). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following magnitudes:
```
  r =3D 19.88 +/- 0.02
  i =3D 19.59 +/- 0.02=20
  Z =3D 19.25 +/- 0.02
  Y =3D 19.19 +/- 0.02
  J =3D 18.97 +/- 0.03
  H =3D 18.80 +/- 0.03
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
Further observations are planned.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.

GCN Circular #22012
GRB 171010A : Optical observations from HCT
Brajesh Kumar, D.K. Sahu, G.C. Anupama and Avinash Singh (Indian Institute of Astrophysics, Bangalore, India) communicate on behalf of a larger Indian collaboration.
We observed the Fermi LAT GRB 171010A (Omodei et al., GCN 21985) field with the 2-m Himalayan Chandra Telescope (HCT) located at Indian Astronomical Observatory, Hanle, India. Multiple frames in Bessell's R and I bands were obtained starting from 18:43 UT on October 11, 2017. The optical afterglow candidate (Thorstensen and Halpern, GCN 21987; Izzo and=A0 Malesani, GCN 21988; Guidorzi et al., GCN 21991; Malesani et al., GCN 22000; Harita et al., GCN 22001; Breeveld and Siegel, GCN 22004) was detected in our individual frames.
The preliminary magnitudes of the OT, calibrated using nearby USNO stars are as follows:

-------------------------------------------------------------------
=A0 Date=A0=A0=A0=A0=A0=A0=A0=A0=A0 Mid UT=A0=A0=A0=A0=A0 Exp (sec)=A0 Fi=
lter=A0=A0 Magnitude
=A0 (YYYY-MM-DD)=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 time
-------------------------------------------------------------------
=A0 2017-10-11=A0=A0=A0 18:46=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 R=A0=A0=A0=A0=A0 18.31 +/- 0.05
=A0 2017-10-11=A0=A0=A0 18:54=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 R=A0=A0=A0=A0=A0 18.38 +/- 0.05
=A0 2017-10-11=A0=A0=A0 20:12=A0=A0=A0=A0=A0=A0 450=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 R=A0=A0=A0=A0=A0 18.42 +/- 0.04
=A0 2017-10-11=A0=A0=A0 21:32=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 R=A0=A0=A0=A0=A0 18.48 +/- 0.05
=A0 2017-10-11=A0=A0=A0 21:46=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 R=A0=A0=A0=A0=A0 18.51 +/- 0.05
-------------------------------------------------------------------
=A0 2017-10-11=A0=A0=A0 20:21=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 I=A0=A0=A0=A0=A0 18.06 +/- 0.05
=A0 2017-10-11=A0=A0=A0 20:28=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 I=A0=A0=A0=A0=A0 18.09 +/- 0.05
=A0 2017-10-11=A0=A0=A0 21:53=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 I=A0=A0=A0=A0=A0 18.22 +/- 0.05
=A0 2017-10-11=A0=A0=A0 22:00=A0=A0=A0=A0=A0=A0 300=A0=A0=A0=A0=A0=A0=A0=A0=
=A0 I=A0=A0=A0=A0=A0 18.24 +/- 0.05
--------------------------------------------------------------------

Contamination due to the host galaxy has not been removed.

GCN Circular #22013
Assaf Horesh (HUJI), Joe Bright, K. P. Mooley, 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) report:
The AMI Large Array triggered on the Fermi-LAT alert for GRB 171010A (Omodei et al., GCN 21985) as part of the 4pisky program. Our initial observations at 15.5 GHz on 2017 Oct 12 reveal an unresolved radio source consistent with the XRT afterglow location (D'Ai et al., GCN 21989), with a flux of ~2.5 mJy. Please note that due to the large AMI beam in this case (~ 100x30 arc-second), the detected source may be contaminated by other radio sources. However, the nearest radio source detected in the NVSS archival data is 6.9 arc-minute away. Further analysis is in progress and future AMI observations are planned. We encourage further radio followup observations.
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/ .
GCN Circular #22014
T. Laskar (NRAO / UC Berkeley), D. L. Coppejans, and R. Margutti (Northwestern University) report on behalf of a larger collaboration:
"We observed GRB 171010A (Omodei et al.; GCN 21985) at multiple frequencies with the VLA beginning on 2017 October 13.32 UT (2.79 days after the burst). At a mean frequency of 6 GHz, we detect a radio source with a preliminary flux density of ~ 0.7 mJy at
```
RA = 04:26:19.4780 +/- 0.0005
Dec = -10:27:46.03 +/- 0.01
```
consistent with the Swift/XRT position (D'Ai et al.; GCN 21989) and the optical position (Halpern et al.; GCN 21987, Izzo et al.; GCN 21988). Follow-up observations are planned. We thank the VLA staff for rapidly scheduling these observations."
GCN Circular #22015
A. Horesh (HUJI), D. A. Perley (LJMU), S. B. Cenko (NASA/GSFC) report:
We observed GRB171010A (Omodei et al., GCN 21985) with the Jansky Very Large Array (VLA) under our Fermi GRB program. The VLA observations were undertaken on 2017 October 13.35 UT. We detected a radio source with a flux of ~1.5 mJy at a central frequency of 10 GHz. The source position is consistent with the position of the reported afterglow (Thorstensen and Halpern, GCN 21987; Izzo and Malesani, GCN 21988; Guidorzi et al., GCN 21991; Malesani et al., GCN 22000; Harita et al., GCN 22001; Breeveld and Siegel, GCN 22004; Watson et al., GCN 22011; Kumar et al., GCN 22012).
Our observations thus confirm the earlier reports of a radio detection (Horesh et al. GCN 22013; Laskar et al. GCN 22014) and suggest that the radio source has a rising spectrum towards higher frequencies.
Further VLA observations are planned. We thank the VLA staff for scheduling these observations.
GCN Circular #22096
A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), J. Selsing (DARK/NBI), D. Malesani (DARK/NBI), D. Xu (NAOC/CAS), L. Izzo (HETH/IAA-CSIC), K. E. Heinz (Univ. Iceland and DARK/NBI), D. A. Kann (HETH/IAA-CSIC), G. Leloudas (DARK/NBI), S. Schulze (WIS), N. R. Tanvir (Univ. Leicester), S. Covino (INAF/Brera), P. D'Avanzo (INAF/Brera), J. P. U. Fynbo (DARK/NBI), D. Hartmann (Clemson Univ.), J. Hjorth (DARK/NBI), C. Kouveliotou (GWU), L. Kaper (API, Univ. Amsterdam), A. J. Levan (Univ. Warwick), A. Melandri (INAF/Brera), P. Moller (ESO), G. Pugliese (API, Univ. Amsterdam), B. Sbarufatti (INAF/Brera and PSU), and P. Schady (MPE), S. Schmidl (TLS), on behalf of the STARGATE collaboration, report:
We observed the optical counterpart of GRB 171010A (Omodei et al., GCN 21985; Poolakkil & Meegan, GCN 21992; Sharma et al., GCN 21990) at z = 0.33 (Kankare et al., GCN 22002) using the ESO Very Large Telescope. Imaging was secured on 2017 Oct 31.25 UT (20.45 days after the GRB) using the VIMOS instrument, in the R and I filters, for a total of 10 min exposure each.
Both the candidate host galaxy of the GRB (Thorstensen & Halpern, GCN 21897; Izzo & Malesani, GCN 21988) and a second compact source, at a location consistent with that of the optical afterglow, are well visible in our images. The spatial coincidence of the second source could indicate late-time emission associated with the GRB, or the presence of an underlying star-forming region.
Spectroscopy covering both the host nucleus and the afterglow location was carried out on 2017 Nov 1.25 UT (21.46 days after the GRB; 16 days in the GRB rest frame), using the X-shooter spectrograph, for a total exposure time of 4x1200 s. The traces of both objects are visible, showing a wealth of narrow nebular emission lines, some of which especially intense at the afterglow location. We measure for the galaxy nucleus a redshift z = 0.3285, consistent with the report by Kankare et al. (GCN 22002).
Faint continuum emission is detected at the GRB location. This could be due to an associated SN, as expected for long GRBs at this redshift, or to an underlying star forming region, or a combination of both. The spectral shape is curved and redder than at the nucleus location, but extinction is low as inferred from the Balmer decrement. This opens the possibility of excess light from the SN. In the attempt to isolate its contribution, we then estimated the host contamination by rescaling the nucleus spectrum assuming it contributes the entire flux at 3500 AA (rest frame), where GRB-associated SNe have negligible emission (e.g. Hjorth et al. 2003, Nature, 423, 847; Mazzali et al. 2003, ApJ, 599, 95), due to metal line blanketing.
By comparing the residual contribution with known SN/GRB templates, we find a good resemblance with other GRB-associated SNe, such as SN 1998bw (at 6 days post maximum; e.g. Patat et al. 2001, ApJ, 555, 900) and SN 2006aj (at 5 days post maximum; e.g. Pian et al., Nature, 442, 1011). Based on this resemblance, the object has been assigned the IAU name of SN 2017htp. The brightness of the SN is about 30% (1.3 mag fainter) than SN 1998bw at a comparable epoch. An accurate computation requires however a more rigorous host subtraction which will be possible with late-time templates.
A plot showing the spectra can be viewed at this URL:
https://wis-tns.weizmann.ac.il/system/files/uploaded/STARGATE/tns_2017htp_classrep_1386_STARGATE.png
We acknowledge unfaltering support from the ESO staff at Paranal, in particular Marcelo Lopez, Juan Carlos Munoz, Nestor Jimenez, Eleonora Sani, Fernando Selman, and Romain Thomas.
>
GCN Circular #22107
A. Cucchiara (University of the Virgin Islands), L. G. Strolger (STScI) report on behalf of a larger collaboration:
We observed the location of the LAT GRB 171010A (Omodei et al., GCN 21985; Poolakkil & Meegan, GCN 21992; Sharma et al., GCN 21990) at z = 0.33 (Kankare et al., GCN 22002) with the 1.3 m Remotely Controlled Telescope (RCT) located at Kitt Peak Observatory in optical R-band. We performed a series of 120s exposures under good conditions (2.2 arcseconds seeing) and airmass of 1.4 on average.
Beginnng October 23.41 UT (12.21 days post burst) we identified an excess over the host galaxy flux and a subsequent fading optical source at the location of the GRB+Host galaxy. These are indicative of a possible supernova component (as suggested by de Ugarte Postigo et al. GCN 22096).
```
T-T0          R Mag
(days)        (Host+SN)
12.21         18.87 +- 0.10
14.21         19.64 +- 0.13
15.21         20.21 +- 0.19
```
The magnitude are calibrated agains several USNO-B1 objects in the field and are not corrected for galactic extinction. Further observations are planned. We thank the RCT Consortium for permitting these observations. RCT is operated by South Carolina State University, Villanova University, and University of Western Kentucky.
GCN Circular #22113
E. Mazaeva (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), E. Klunko (ISTP), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin (Fesenkov Astrophysical Institute), O. Burhonov (UBAI), A. Volnova (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Fermi-LAT GRB 171010A (Omodei et al., GCN 21985) with Zeiss-1000 telescope (TSHAO), AZT-33IK telescope (Mondy), ZTSH2.6m telescope (CrAO) and AZT-22 telescope (Maidanak). Within the enhanced Swift-XRT circle (D'Ai et al., GCN 21989) we clearly detect the optical afterglow (Thorstensen & Halpern , GCN 21987; Izzo & D. Malesani, GCN 21988; Guidorzi et al., GCN 21991; Malesani et al., GCN 22000; Harita et al., GCN 22001; Kankare et al., GCN 22002; Breeveld & Siegel, GCN 22004; Watson et al., GCN 22011; Kumar et al., GCN 22012).
Still not all data received and we report some preliminary photometry of the afterglow in earlier epochs and host+OT in R-filter:
```
Date=A0=A0=A0=A0 =A0 UT_start =A0 t-T0 =A0=A0=A0=A0  OT =A0 =A0 Err.=A0=A0=
=A0 Up.Lim.   Telescope
  =A0=A0=A0=A0=A0=A0=A0=A0 =A0(mid, days)=A0=A0 =A0 =A0  =A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (3 sigma)
2017-10-12 20:11:03  2.11360     19.06  0.04    22.4      Zeiss-1000
2017-10-13 18:34:36=A0 3.00616=A0=A0  =A019.21=A0 0.05=A0=A0 =A022.2      AZT-33IK
2017-10-14 18:23:31=A0 3.99492=A0=A0  =A019.38=A0 0.03=A0=A0 =A023.1      AZT-33IK
2017-10-15 18:23:04=A0 4.99461=A0=A0  =A019.35=A0 0.03=A0=A0 =A023.0      AZT-33IK
2017-10-20 00:57:51  9.26249     19.60  0.03    23.4      ZTSH2.6
2017-10-28 19:42:20 18.04966     19.50  0.06    22.8      AZT-33IK
2017-11-06 19:44:54 27.07226     20.00  0.10    21.4      AZT-22
```
The photometry is based on nearby USNO-B1.0 stars
```
USNO-B.1_id     R2
0795-0045061    15.10
0795-0045035    17.25
0795-0045066    16.59
```
A light curve of the OT+host can be found in=20 http://grb.rssi.ru/GRB171010A/GRB171010A_light_curve_R.png
As can be seen from the light curve we can support discovery of SN=20 2017htp (de Ugarte Postigo et al., GCN 22096; Cucchiara et al., GCN 22107= ). We will update the LC as more data becomes available.

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Jochen Greiner, last update: 09-Nov-2017 [Disclaimer]