Gamma-ray Burst 160310A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 10 Mar 16 09:00:59 UT
NOTICE_TYPE:     Fermi-LAT Offline Position
TRIGGER_NUM:     479262182     
GRB_RA:           98.780d {+06h 35m 07s} (J2000),
                  98.976d {+06h 35m 54s} (current),
                  98.174d {+06h 32m 42s} (1950)
GRB_DEC:          -7.110d {-07d 06' 35"} (J2000),
                  -7.124d {-07d 07' 25"} (current),
                  -7.069d {-07d 04' 07"} (1950)
GRB_ERROR:       6.00 [arcmin radius, 90% containment, statistical only]
GRB_DATE:        17457 TJD;    70 DOY;   16/03/10
GRB_TIME:        1378.47 SOD {00:22:58.47} UT 
TRIGGER_ID:      0x20000000
MISC:            0x40000000
SUN_POSTN:       351.02d {+23h 24m 04s}   -3.87d {-03d 52' 18"}
SUN_DIST:        107.27 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
MOON_POSTN:        8.26d {+00h 33m 03s}   +2.01d {+02d 00' 43"}
MOON_DIST:        90.96 [deg]  
MOON_ILLUM:      3 [%]
GAL_COORDS:      217.44, -6.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      100.10,-30.24 [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 #19158
G. Vianello (Stanford), M. Yassine (CNRS/IN2P3), E.Moretti (MPP Munich)
report on behalf of the Fermi-LAT team:
At 00:22:58.47 on March, 10, 2016 (T0) Fermi-LAT detected high-energy emission from GRB 160310A, which was also detected by Fermi-GBM (trigger 479262181 / 160310016).
The best LAT on-ground location is found to be
RA, Dec = 98.78, -7.11 (J2000)
with an error radius of 0.1 deg (90 % containment, statistical error only).
This was 62 deg from the LAT boresight at the time of the trigger, on the edge of the field of view.
The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance.
At the time of the trigger Fermi was in normal survey mode. The GRB was observable by Fermi from T0 to ~T0 + 500 s, and then again from ~T0 + 5200 s and T0 + 7000 s. The highest-energy photon is a 30 GeV event which is observed 5800 seconds after the GBM trigger.
A Swift ToO has been requested for this burst.
The Fermi-LAT point of contact for this burst is Giacomo Vianello (giacomov@stanford.edu).
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 #19159
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/LAT GRB 160310A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020602
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 #19161
Kilian Toelge (MPE) and Michelle Hui (UAH) report on behalf of the Fermi GBM Team:
"At 00:22:58.47 UT on 10 March 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160310A (trigger 479262182 / 160310016), which was also detected by the LAT (G.Vianello et al. 2016, GCN 19158) The GBM on-ground location is consistent with the LAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is 68 degrees.
The GBM light curve shows/consists of five pulses with a duration (T90) of about 18.2 s (50-300 keV). The time-averaged spectrum from T0-0.5 s to T0+20.0 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.1 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 129.0 +/- 9.5 keV.
The event fluence (10-1000 keV) in this time interval is (4.8 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+11.8 s in the 10-1000 keV band is 7.1 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 10 Mar 16 16:06:54 UT
NOTICE_TYPE:     Fermi-LAT Offline Position
TRIGGER_NUM:     479262182
GRB_RA:           98.780d {+06h 35m 07s} (J2000), 
                  98.976d {+06h 35m 54s} (current), 
                  98.174d {+06h 32m 42s} (1950) 
GRB_DEC:          -7.110d {-07d 06' 35"} (J2000),  
                  -7.124d {-07d 07' 25"} (current), 
                  -7.069d {-07d 04' 07"} (1950) 
GRB_ERROR:       6.00 [arcmin radius, 90% containment, statistical only] 
GRB_DATE:        17457 TJD;    70 DOY;   16/03/10 
GRB_TIME:        1378.47 SOD {00:22:58.47} UT 
TRIGGER_ID:      0x20000000 
MISC:            0x40000000 
SUN_POSTN:       351.29d {+23h 25m 09s}   -3.76d {-03d 45' 20"} 
SUN_DIST:        107.02 [deg]   Sun_angle= -7.2 [hr] (East of Sun) 
MOON_POSTN:       12.49d {+00h 49m 57s}   +3.40d {+03d 23' 47"} 
MOON_DIST:        86.94 [deg] 
MOON_ILLUM:      4 [%] 
GAL_COORDS:      217.44, -6.85 [deg] galactic lon,lat of the burst (or transient) 
ECL_COORDS:      100.10,-30.24 [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/BACODINE POSITION NOTICE

TITLE:          GCN/GRB_COUNTERPART POSITION NOTICE
NOTICE_DATE:    Thu 10 Mar 16 17:47:10 UT 
NOTICE_TYPE:    Other
TRIGGER_NUM:    20602
CNTRPART_RA:     98.8225d {+06h 35m 17.4s} (J2000),
                 99.0186d {+06h 36m 04.4s} (current),
                 98.2167d {+06h 32m 52.0s} (1950)
CNTRPART_DEC:    -7.2155d {-07d 12' 55.7"} (J2000),
                 -7.2295d {-07d 13' 46.1"} (current),
                 -7.1743d {-07d 10' 27.3"} (1950)
CNTRPART_ERROR: 3.6 [arcsec, radius]
GRB_DATE:       17457 TJD;    70 DOY;   16/03/10
GRB_TIME:       1362.00 SOD {00:22:42.00} UT
OBS_DATE:       17457 TJD;    70 DOY;   16/03/10
OBS_TIME:       41620.0 SOD {11:33:40.00} UT
OBS_DUR:        2224.0 [sec]   
INTENSITY:      1.10e-13 +/- 4.00e-14 [erg/cm2/sec] 
ENERGY:         0.3-10 [keV]
TELESCOPE:      Swift-XRT
SUBMITTER:      Phil_Evans
SUN_POSTN:      351.35d {+23h 25m 25s}   -3.73d {-03d 43' 41"} 
SUN_DIST:       106.99 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
MOON_POSTN:      13.48d {+00h 53m 56s}   +3.72d {+03d 43' 10"}
MOON_DIST:       86.05 [deg]
MOON_ILLUM:     4 [%]          
GAL_COORDS:     217.55, -6.86 [deg] galactic lon,lat of the counterpart  
ECL_COORDS:     100.16,-30.34 [deg] ecliptic lon,lat of the counterpart
COMMENTS:       GRB COUNTERPART Coordinates.
COMMENTS:       Swift is performing multiple tiled observations of this GRB.
COMMENTS:       This object is uncatalogued.
COMMENTS:       The INTENSITY is the OBSERVED flux.
COMMENTS:       See http://www.swift.ac.uk/ToO_GRBs/00020602/index_2.php for more details.
COMMENTS:       We cannot confirm whether this is the GRB or serendipitous.

GCN Circular #19162
S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU) 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 160310A (Vianello et al. GCN Circ. 19158), collecting 3.0 ks of Photon Counting (PC) mode data between T0+40.3 ks and T0+46.7 ks.
One uncatalogued X-ray source has been detected inside or close to the Fermi/LAT error region, it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:
Source 2:
```
  RA (J2000.0):  98.8226  =  06:35:17.42
  Dec (J2000.0): -7.2156  =  -07:12:56.1
  Error: 5.1 arcsec (radius, 90% conf.)
  Count-rate: (5.2 +/- 1.9)e-3 ct s^-1
  Flux: (1.18 +/- 0.43)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
```
Another uncatalogued was also detected, however this was too far from the GRB position to be the afterglow.
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/00020602.
This circular is an official product of the Swift-XRT team.
GCN Circular #19163
D. Xu (NAOC/CAS) reports on behalf of a collaboration:
We observed the field of GRB 160310A (Vianello et al., GCN 19158) using the LCOGT 1-m located at Sutherland, South Africa. Observations started at 18:57:18 UT on 2016-03-10 (i.e., 18.75 hr after the burst) and 2x300s frames were obtained in R- and I-band each.
No credible source is detected within or at the edge of the error circle of the XRT Source 2 reported in Gibson et al. (GCN 19162), down to limiting magnitudes of R~20.0 and I~18.6, respectively.
GCN Circular #19164
T. Kruehler (MPE Garching), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. Malesani (DARK/NBI), and T. Kuutma (NOT) report on behalf of a larger collaboration:
We observed the field of GRB 160310A (Vianello et al., GCN #19158, Toelge & Hui, GCN #19161) with the NOT equipped with ALFOSC. Imaging in the i-band filter started at 20:40:57 UT on 2016-03-10, 20.3 hr after the GRB trigger.
In a combined image of 5x120 s exposure time, we detect a single source in the XRT error circle (Gibson et al. GCN#19162) at a position of
```
RA (J2000.0) = 06:35:17.33
Dec. (J2000.0) = -07:12:56.0
```
with an uncertainty of 0".5 in each coordinate.
Calibrating our image against I-band magnitudes from field stars of the USNO-B1 catalog, we measure a preliminary brightness of
I = 21.4 +- 0.2 mag
not corrected for the expected foreground extinction corresponding to a reddening of E_B-V = 0.486 mag (Schlafly & Finkbeiner 2011)
The field is relatively crowded, and chance coincidences in the 5.1" error circle are not unlikely. No statement about possible variability can be made at this point.
GCN Circular #19166
Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),=20 Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer=20 (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),=20 Antonino Cucchiara (GSFC/STScI), Owen Littlejohns (ASU), Enrico=20 Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM),=20 Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels= (GSFC),=20 Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and=20 Vicki Toy (UMD) report:
We observed the field of the Fermi GRB 160310A (Vianello, et al., GCN=20 19158; Toelge, et al., GCN 19161) with the Reionization and Transients=20 Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson=20 Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro=20 M=E1rtir from 2016/03 11.16 to 2016/03 11.32 UTC (27.46 to 31.25 hours=20 after the GBM trigger).
We observed the two uncatalogued X-ray sources detected by the Swift/XRT=20 (Gibson, et al., 19162). For source #1 we obtained a total of 1.07 hours=20 exposure in the r and i bands and 0.45 hours exposure in the J, and H=20 bands. For a source within the XRT error circle, in comparison with the=20 USNO-B1 and 2MASS catalogs, we obtain the following detections:
```
   r    19.89 =B1 0.02
   i    19.34 =B1 0.01
   J    18.03 =B1 0.01
   H    17.37 =B1 0.01
```
These values are consistent with the magnitudes of a USNO-B1 catalogued=20 object. No other source is visible within the XRT localization.
For source#2 we obtained a total of 1.78 hours exposure in the r and i=20 bands and 0.75 hours exposure in the J, and H bands. For a source within=20 the XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs,=20 we obtain the following detections:
```
   r    22.48 =B1 0.09
   i    21.82 =B1 0.05
   J    20.62 =B1 0.10
   H    20.03 =B1 0.08
```
These magnitudes are in the AB system and are not corrected for Galactic=20 extinction in the direction of the GRB. Our values are slightly fainter=20 than the NOT detection (Kruehler, et al., GCN 19164), although no strong=20 claim about variability can be made at this time. Further observations=20 to determine the nature of source #2 are encouraged.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #19167
```
Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
```
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 160310A (Fermi/LAT detection: Vianello et al., GCN 19158; Fermi/GBM detection: Toelge & Hui, GCN 19161) triggered Konus-Wind at T0=3D1391.997 s UT (00:23:11.997).
The light curve shows a multi-peaked pulse which started at ~T0-14 s and lasted until ~T0+15 s (the total duration is ~30 s). The emission is seen up to ~4 MeV.
As observed by Konus-Wind, the burst had a fluence of (6.8 =B1 1.5)x10^-6 erg/cm2 and a 64-ms peak energy flux, measured from T0-0.192, of (2.1 =B1 0.4)x10^-6 erg/cm2 (both in the 20 keV - 10 MeV energy range).
The spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a cutoff power-law (CPL) function with the following model parameters: the photon index alpha =3D -1.40(-0.16,+0.21), and the peak energy Ep =3D 316(-95,+206) keV, chi2 =3D 89/85 dof. Fitting this spectrum with the GRB (Band) function yields the same alpha and Ep with only an upper limit on beta of -2.0, chi2 =3D 89/94 dof.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160310_T01391/
In the KW waiting mode data, GRB 160310A was preceded by a weaker, GRB-like event lasting from ~T0-1510 s to ~T0-1418 s (the total duration is ~90 s). Modeling the KW 3-channel spectrum for this episode by the CPL function yields alpha =3D -1.23 =B1 0.24, Ep =3D 142 =B1 57 ke= V, and a 20--1500 keV fluence of (7.7 =B1 1.7)x10^-6 erg/cm2. The KW ecliptic latitude response for this event is consistent with that for GRB 160310A. Taking this into account, we suggest a possibility that GRB 160310A is, in fact, a double-episode, ultra-long GRB with a total duration of ~1500 s.
All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.
GCN Circular #19168
F. E. Marshall (NASA/GSFC) and A. Maselli (INAF/IASF) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160310A 40247 s after the LAT trigger (Vianello et al., GCN Circ. 19158). No source is detected in the initial UVOT exposures at a position consistent with the position of the possible XRT afterglow (Gibson et al., GCN Circ. 19162) or the possible optical counterpart (Kruehler et al., GCN Circ. 19164). Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

u                40247        46726         1273         >20.4
white            41072        41890          805         >21.3
v                41897        42757          843         >19.9
```
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 (Schlegel et al. 1998).
GCN Circular #19169
T. Kruehler (MPE Garching), G. Leloudas (Weizmann Institute, DARK/NBI), D. Malesani (DARK/NBI), and T. Kuutma (NOT) report on behalf of a larger collaboration:
We again observed the field of GRB 160310A (Vianello et al., GCN #19158, Toelge & Hui, GCN #19161) with the NOT equipped with ALFOSC. A second epoch of imaging in the I-band filter was obtained starting at 20:21:05 UT on 2016-03-11, 48.0 hr after the GRB trigger.
In a combined image of 5x120 s exposure time, we still detect the same source in the XRT error circle at a brightness comparable to the observations 24 hours earlier (Kruehler et al., GCN #19164, see also Troja et al., GCN #19166), indicating that it is likely not the optical afterglow of GRB 160310A.
GCN Circular #19170
E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB160310.02 23 sec after notice time and 56663 sec after trigger time at 2016-03-10 16:07:21 UT. We not found optical transient around and inside LAT error-box (ra=06 35 05 dec=-07 06 34 r=1 degree) brighter then 19.0 .
The message may be cited.
GCN Circular #19205
A. Maselli (INAF-IASFPA) and P. A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
On 2016 March 16, Swift-XRT has carried out a further observation of the field of GRB 160310A detected by Fermi (Vianello et al., GCN Circ. 19158; Toelge and Hui, GCN Circ. 19161), collecting 4.0 ks of data from T0+569 ks to T0+599 ks. The X-ray source reported by Gibson et al. (GCN Circ. 19162) is still detected with a count rate of (5.5+/-1.8)E-03 ct/s, showing no evidence of fading. Therefore, this source is not related to the GRB. The 3-sigma upper limit for the observation carried out between T0+40.3 ks and T0+46.7 ks, computed at the center of the Fermi-LAT error circle, is 3.8E-03 ct/s. We conclude that no afterglow has been identified by Swift-XRT for GRB 160310A.
This circular is an official product of the Swift-XRT team.
GCN Circular #19209
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team,
K. Hurley, on behalf of the IPN,
V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, and
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, report:
The long-duration GRB 160310A was detected by Konus-Wind (Frederiks et al., GCN Circ. 19167), Fermi (LAT: Vianello et al., GCN Circ. 19158 and GBM: Toelge & Hui GCN Circ. 19167), and Swift (BAT), at about 1378 s UT (00:22:58). The burst was outside the coded field of view of the BAT.
We have triangulated it to a Konus-GBM annulus centered at RA(2000)=178.455 deg (11h 53m 49s) Dec(2000)=-2.131 deg (-2d 07' 52"), whose radius is 76.571 +/- 0.876 deg (3 sigma) and to a Konus-BAT annulus centered at RA(2000)=178.592 deg (11h 54m 22s) Dec(2000)=-2.265 deg (-2d 15' 53"), whose radius is 76.187 +/- 1.716 deg (3 sigma).
While the GBM position is in a good agreement with both the Konus-GBM and the Konus-BAT annuli, the LAT position reported in GCN 19158 is 2.9 deg (~10 sigma) from the Konus-GBM annulus center line. So we encourage further investigation of the LAT position.
Using the method suggested by Pal'shin, et al., ApJS 207, 38, 2013 (sec. 4.2.1) and assuming a LAT error radius of 6 deg, we obtain the following joint LAT/IPN error box:
```
--------------------------------
  RA(2000), deg    Dec(2000), deg
--------------------------------
Center:
    101.726         -7.1445
Corners:
    100.850         -13.082
    102.648         -13.076
    102.726         -1.228
    100.975         -1.191
---------------------------------
```
The error box area is 21 sq. deg, and its maximum dimension is 12 deg (the minimum one is 1.8 deg).
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB160310_T01391/IPN/
GCN Circular #19210
Ilia V. Sokolov (Terskol Peak Observatory), M. Andreev (Terskol Peak Observatory), A. Sergeev (Terskol Peak Observatory), A. Moskvitin (SAO RAS) report:
We observed the GRB160310A field 17h 57m 26s after the trigger (Fermi trigger number 479262182) in R-band with a total exposure of 13 x 120 s. We detected a source brighter than in SDSS images at RA = 06:35:14.4 Dec = -07:03:49.0 with the R magnitude 20.34. The magnitude is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.53 in the direction of the burst (Schlegel et al. 1998). The photometry is based on USNO-b1 stars.

Back to JG's homepage

Jochen Greiner, last update: 21-Mar-2016 [Disclaimer]