Gamma-ray Burst 190501A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN Circular #24360
A. Ursi (INAF/IAPS), F. Verrecchia, F. Lucarelli (SSDC, and INAF/OAR), N. Parmiggiani (INAF/OAS-Bologna), C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), A. Bulgarelli, V. Fioretti, F. Fuschino, (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team:
AGILE detected a long burst at T0 = 2019-05-01 05:23:23.58 +/- 0.01 s (UTC).
The event is visible in the scientific ratemeters (RMs) of the Super-AGILE (SA, 18-60 keV), Anti-Coincidence (AC, 50-200 keV), and Mini-Calorimeter (MCAL, 0.4-100 MeV) detectors. Their light curves show a multi-peaked FRED profile, lasting ~24 s and releasing ~11200 counts in the SA RMs, lasting ~15 s and releasing ~2000 counts in the AC RMs, and lasting ~18 s and releasing ~20200 counts in the MCAL RMs. The ratemeters light curves can be found at http://www.agilescienceapp.it/notices/GRB_062362_483773003.584545_RM.png.
The event also triggered a Mini-Calorimeter (MCAL) data acquisition lasting ~8.6 s and releasing a total number of ~10140 counts in the detector (in the 0.4-100 MeV energy range). The MCAL light curve can be found at: http://www.agilescienceapp.it/notices/GRB_062362_483773003.584545.png.
Further analysis of the Gamma-Ray Imaging Detector (GRID) data is still in progress.
The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.
GCN Circular #24361
F. Lucarelli, F. Verrecchia (SSDC, and INAF/OAR), G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, Y. Evangelista, A. Ursi (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino (INAF/OAS), M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team:
The Gamma-Ray Imaging Detector (GRID) of AGILE detected a gamma-ray transient temporally coincident with the long bright GRB 190501A reported by Ursi et al., GCN #24360. Given the rarity of this transient, we consider it the gamma-ray counterpart of GRB 190501A.
A preliminary GRID analysis in the energy range 30 MeV - 1 GeV shows a detection with a statistical significance of about 18 sigma, at the sky position R.A., Decl. (J2000): 174,+65 +/- 5 deg (Galactic coordinates l,b: 135,+50 deg), over a time integration of 20 s starting from the T0 of GRB 190501A.
The preliminary estimated position is below the GRID 30 deg off-axis angle.
These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.
GCN Circular #24363
F. Verrecchia, F. Lucarelli (SSDC, and INAF/OAR), G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Giuliani (INAF/IASF-Mi), M. Cardillo, C. Casentini, A. Ursi (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), Y. Evangelista (INAF/IAPS), A. Bulgarelli, V. Fioretti, N. Parmiggiani, F. Fuschino (INAF/OAS), M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), I. Donnarumma (ASI), report on behalf of the AGILE Team:
We refined the position of the long GRB 190501A detected by the Gamma-Ray Imaging Detector (GRID) of AGILE (Lucarelli et al., GCN #24361) and previously reported by Ursi et al., GCN #24360. A preliminary maximum likelihood analysis integrating from T0 to T0+500 s yields a detection at 7 sigma with an average flux of F(E> 30 MeV)=(50+/-15)e-05 ph/cm^2/s, with the positional error box centered at R.A., Dec. (J2000) = 172.8, 64.1 deg with a mean radius of 0.8 deg (95% stat. c.l.) [ Galactic coordinates (l,b)=(136.6, 50.8) deg ].
This is among the most intense gamma-ray flux ever detected by AGILE from a GRB.
These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.
GCN Circular #24370
J.Lyman(1), K.Ulaczyk(1), K.Wiersema(1), D.Steeghs(1), M.Dyer(3), D.Galloway(2), V.Dhillon(3), P.O'Brien(4), G.Ramsay(5), D.Pollacco(1), E.Thrane(2), S.Poshyachinda(6), E.Palle(7), R.Cutter(1), A.Levan(1), T. Marsh(1), R.West(1), B.Gompertz(1), E.Stanway(1), K.Ackley(2), A.Obradovic(2), Y-L.Mong(2), A.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3), S.Littlefair(3), L.Makrygianni(3), E.Daw(3), J.Maund(3), R.Starling(4), R.Eyles(4), S.Tooke(4), U.Sawangwit(6), D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6), P.Irawati(6), M.Kennedy(8), R.Breton(8), D.Mata-Sanchez(8), T.Heikkila(9), R.Kotak(9) (1) Warwick University; (2) Monash University; (3) Univ. of Sheffield; (4) University of Leicester; (5) Armagh Observatory & Planetarium; (6) National Astronomical Research Institute of Thailand; (7) Instituto de Astrofisica de Canarias; (8) Univ. of Manchester; (9) University of Turku
report on behalf of the GOTO collaboration:
We report on optical observations with the Gravitational-wave Optical Transient Observer in response to the AGILE detected GRB 190501A (Ursi et al. GCN #24360).
The refined position reported in Verrecchia et al. (GCN #24363) was covered with a set of 5x90s exposures starting at 2019-05-01T20:49 (15.4 hours after the burst) using our wide L filter (400-700 nm).
No viable counterpart is detected using a difference imaging analysis based on recent survey observations of the same pointing. We achieved a 5-sigma detection limit of g=20, based on a photometric calibration against PS1 stars.
GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT) and the Instituto de Astrofisica de Canarias (IAC) (https://goto-observatory.org/)
GCN Circular #24371
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the AGILE GRB 190501A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020892
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 AGILE 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 #24372
K. Hurley, on behalf of the IPN,
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
A. Ursi, N. Parmiggiani, F. Verrecchia, A. Bulgarelli, A. Trois, M. Marisaldi, C. Pittori, M. Tavani, Y. Evangelista, I. Donnarumma, M. Cardillo, G. Piano, G. Minervini, A. Argan, F. Lucarelli, A. Zoli, V. Fioretti, F. Fuschino, M. Pilia, F. Longo, A. Giuliani on behalf of the AGILE team, and
W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report:
The long-duration, very bright GRB 190501A (AGILE-MCAL detection: Ursi et al., GCN Circ. 24360; AGILE-GRID detection: Lucarelli et al., GCN Circ. 24361; AGILE-GRID refined position: Verrecchia et al., GCN Circ. 24363) was detected by AGILE (MCAL, GRID), INTEGRAL (SPI-ACS), Konus-Wind, Mars-Odyssey (HEND), and CALET (GBM), at about 19395 s UT (05:23:15).
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   173.591 (11h 34m 22s) +62.105 (+62d 06' 18")
  Corners:
   173.345 (11h 33m 23s) +61.440 (+61d 26' 24")
   174.192 (11h 36m 46s) +62.859 (+62d 51' 32")
   173.840 (11h 35m 22s) +62.766 (+62d 45' 57")
   173.007 (11h 32m 02s) +61.342 (+61d 20' 32")
  ---------------------------------------------
```
The error box area is about 691 sq. arcmin, and its maximum dimension is 1.615 deg (the minimum one is 7.8 arcmin). The Sun distance was about 95 deg.
This box may be improved.
The AGILE (GRID) refined position (RA, Dec, Rerr = 172.8, 64.1, 0.8 deg) reported in Verrecchia et al. is inconsistent with the box, the minimum distance between the box and the center of the AGILE (GRID) location is ~1.39 deg.
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB190501_T19401/IPN
The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #24406
S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), T. Tamura, Y. Shimizu (Kanagawa U), N. Cannady, M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena) and the CALET collaboration:
The long bright GRB 190501A (AGILE/MCAL detection: Ursi et al., GCN Circ. 24360; AGILE/GRID detection and localization: Lucarelli et al., GCN Circ. 24361, Verrecchia et al. GCN Circ. 24363; IPN triangulation: Hurley et al., GCN Circ. 24372) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:23:17.604 UTC on 1 May 2019. The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure which starts at T=1.9 sec, peaks at 6.0 sec and ends at T+27.4 sec. The T90 and T50 durations measured by the SGM data are 15.5 +- 3.5 sec and 6.8 +- 0.6 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1240723364/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #24419
Phil Evans (U. Leicester) and F.E. Marshall (NASA/GSFC) report on behalf of the Swift team:
Swift-XRT has performed follow-up observations of the AGILE-detected burst GRB 190501A (Ursi et al. GCN Circ. 24360), collecting 2.9 ks of Photon Counting (PC) mode data between T0+146.7 ks and T0+157.7 ks. The XRT field-of-view covers about 7% of the AGILE/GRID 95%-confidence error region (Verrecchia et al. GCN Circ. 24363) and none of the IPN 3-sigma error region (Hurley et al. GCN Circ. 24732).
No uncatalogued X-ray sources have been detected. The 3-sigma upper limit in the field ranges from ~0.003 to ~0.004 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.2e-13 to 1.7e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
Three previously-catalogued X-ray sources have been detected, however their status as catalogued objects makes them unlikely 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/00020892.
The Swift/UVOT began settled observations of the field of GRB 190501A 146672 s after the AGILE trigger. No optical afterglow consistent with the AGILE/GRID position is detected in the initial UVOT exposures. The UVOT images cover about 4% of the 95%-confidence AGILE/GRID error region and none of the IPN 3-sigma error region. 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

white           147234       153893          933         >21.8
v               147796       154103          761         >20.0
u               146672       157636         1167         >20.7
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
This circular is an official product of the Swift team.
GCN Circular #24452
A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report:
The long-duration, bright GRB 190501A (AGILE/MCAL and scientific ratemeters detection: Ursi et al., GCN 24360; AGILE/GRID detection: Lucarelli et al., GCN 24361; Verrecchia et al., GCN 24363; IPN Triangulation: Hurley et al., GCN 24372; CALET Gamma-Ray Burst Monitor detection: Ricciarini t al., GCN 24406) triggered Konus-Wind at T0=19401.146 s UT (05:23:21.146).
The burst light curve shows a bright, multi-peaked pulse with a duration of ~50 s followed by a weak tail up to 137 s. The emission is seen up to ~1200 keV, no KW data above 1.2 MeV are available at the time of writing.
As observed by Konus-Wind, the burst had a fluence of 2.04(-0.13,+0.13)x10^-4 erg/cm2, and a 64-ms peak energy flux, measured from T0+4.272 s, of 3.55(-0.99,+0.99)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+22.784 s) is best fit in the 20 keV - 1.2 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.91(-0.04,+0.04), the high energy photon index beta = -2.10(-0.09,+0.08), the peak energy Ep = 316(-23,+24) keV, chi2 = 70/59 dof.
The spectrum near the peak count rate (measured from T0+3.840 to T0+4.352 s) is best fit in the 20 keV - 1.2 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.65(-0.11,+0.14), the high energy photon index beta = -2.28(-1.52,+0.31), the peak energy Ep = 410(-72,+77) keV, chi2 = 53/47 dof.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB190501_T19401/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.

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Jochen Greiner, last update: 10-May-2019 [Disclaimer]