//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26031 SUBJECT: GRB 191019A: Swift detection of a burst DATE: 19/10/19 15:21:47 GMT FROM: David Palmer at LANL K. K. Simpson (PSU), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 15:12:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191019A (trigger=930285). Swift did not slew due to an observing constraint. The BAT on-board calculated location is RA, Dec 340.038, -17.333, which is RA(J2000) = 22h 40m 09s Dec(J2000) = -17d 19' 59" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks in a FRED envelope with a total duration of about 80 sec. The peak count rate was ~4500 counts/sec (15-350 keV), at ~4 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+51.6 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is K. K. Simpson (kira.simpson1984 AT gmail.com). 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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26032 SUBJECT: GRB 191019A: MASTER optical observation DATE: 19/10/19 15:46:07 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, N.Tiurina, E. Gorbovskoy, V.Kornilov, F.Balakin,P.Balanutsa,A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov,V.Senik, T.Pogrosheva, K.Pozdnyakov,A.Chasovnikov, V.Topolev, D.Kuvshinov(Lomonosov Moscow State University, SAI,Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico FelixAguilar OAFA), H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova(Irkutsk State University, API), A. Tlatov, D. Dormidontov(Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational StateUniversity) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L) started Swift GRB191019A (Simpson et al. GCN26031 , BAT, RA,Dec= RA(J2000) = 22h 40m 09s, -17d 19' 59") observations at 2019-10-19 15:13:14Ut with exp. 10s, but sun altitude=-10. The first image with mlim=15.0 made at 2019-10-19 15:23:59UT. Real time updated cover map and possibly OT, that can be discovered, will be available here: https://master.sai.msu.ru/site/master2/event.php?id=1171578 The observation and reduction will be continued. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26033 SUBJECT: Swift GRB191019.63: Global MASTER-Net observations report DATE: 19/10/19 16:18:27 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB191019.63 (trigger No 930285,22h 40m 09.120s , -17d 19m 58.80s, R=0.05) errorbox 610 sec after notice time and 685 sec after trigger time at 2019-10-19 15:23:59 UT, with upper limit up to 18.2 mag. Observations started at twilight. The observations began at zenit distance = 70 deg. The sun altitude is -11.9 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1171584 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 756 | MASTER-Kislovodsk | P| | 140 | 14.9 | 921 | MASTER-Kislovodsk | P| | 170 | 17.3 | 1107 | MASTER-Kislovodsk | P- | 180 | 17.4 | 1107 | MASTER-Kislovodsk | P| | 180 | 17.8 | 1311 | MASTER-Kislovodsk | P- | 180 | 17.7 | 1311 | MASTER-Kislovodsk | P| | 180 | 18.0 | 1515 | MASTER-Kislovodsk | P- | 180 | 17.8 | 1515 | MASTER-Kislovodsk | P| | 180 | 18.1 | 1720 | MASTER-Kislovodsk | P- | 180 | 17.7 | 1720 | MASTER-Kislovodsk | P| | 180 | 18.0 | 1924 | MASTER-Kislovodsk | P- | 180 | 17.9 | 1924 | MASTER-Kislovodsk | P| | 180 | 18.1 | 2135 | MASTER-Kislovodsk | P- | 180 | 18.0 | 2135 | MASTER-Kislovodsk | P| | 180 | 18.2 | 2348 | MASTER-Kislovodsk | P| | 180 | 18.2 | 2348 | MASTER-Kislovodsk | P- | 180 | 18.0 | 2553 | MASTER-Kislovodsk | P- | 180 | 17.9 | 2553 | MASTER-Kislovodsk | P| | 180 | 18.1 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26034 SUBJECT: GRB 191019A: Swift-XRT observations DATE: 19/10/19 16:22:58 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU), S. Campana (INAF-OAB) and G. Cusumano (INAF-IASF PA) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 191019A at 16:06:04.5 UT, 3210.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 340.0244, -17.3286 which is equivalent to: RA(J2000) = 22h 40m 05.86s Dec(J2000) = -17d 19' 42.9" with an uncertainty of 3.1 arcseconds (radius, 90% containment). This location is 49 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.28 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.5 (+2.44/-3.29) x 10^22 cm^-2 (90% confidence). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26036 SUBJECT: GRB 191019A: TSHAO optical observations, probable afterglow and host galaxy DATE: 19/10/19 18:55:20 GMT FROM: Alexei Pozanenko at IKI, Moscow I. Reva (FAPHI), A. Pozanenko (IKI), M. Krugov (FAPHI), S. Belkin (IKI), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN: We observed the field of GRB 191019A (Simpson et al. GCN 26031) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on Oct. 19 (UT) 15:26:32, i.e. 14 minutes after GRB trigger. Within XRT error circle (Evans et al., GCN 26034) we found only one source which is presented in catalogs. Preliminary photometry of the source is following. Date UT start t-T0 Filter Exp. OT Err. (mid, days) (s) 2019-10-19 15:26:32 0.013877 R 720 18.37 0.03 The photometry is based nearby USNO-B1.0 stars. The brightness of the catalogued source is R2(USNO-B1.0 340.024514480) = 19.36 and r'(Pan-STARRS 0726-1153339) = 19.30. The source is probably a host galaxy of GRB 191019A and we suggest the afterglow of the source on a top of the host galaxy. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26039 SUBJECT: GRB 191019A: NOT optical observations DATE: 19/10/19 21:30:22 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU), D. B. Malesani (DTU Space), A. de Ugarte Postigo (HETH, IAA/CSIC; DARK/NBI), D. Xu (NAO/CAS), J. P. U. Fynbo (DAWN/NBI), K. E. Heintz (Univ. Iceland), and N. E. Jannsen (NOT) report on behalf of a larger collaboration: We observed the field of GRB 191019A (Simpson et al., GCN 26031) with the Nordic Optical Telescope (NOT) equipped with the ALFOSC imaging camera. Observations started on 2019 Oct 19.822 UT (4.52 hr after the trigger). In a single 120 s image taken in the SDSS i band, we detect the object mentioned by Reva et al. (GCN 26036), which is also visible in the Pan-STARRS archival images and is consistent with the X-ray position (Evans et al., GCN 26034). The target is clearly extended (FWHM 1.4" with a seeing of 1.1"). The object centroid has coordinates (J2000, calibrated against the Gaia catalog): RA = 22:40:05.89 Dec = -17:19:42.7 Measuring its magnitude over an aperture of 1.7" radius, we obtain i = 18.66 +/- 0.01 AB (statistical error), compared to i = 18.71 +/- 0.01 from the Pan-STARRS catalog (Chambers et al. 2015, arXiv:1612.05560), confirmed by our own measurement on the i-band Pan-STARRS image. The small flux difference may be due to calibration, color effects, or variable aperture correction, so we do not claim any afterglow detection. A conservative limit on the afterglow magnitude at the time of our observation would be i > 21. We note the elevated column density measured in a preliminary analysis of the X-ray spectra (Evans et al., GCN 26034). This may suggest a dust-obscured event. DisclaimerNone //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26041 SUBJECT: GRB 191019A: NOT optical spectroscopy of candidate counterpart DATE: 19/10/19 23:47:11 GMT FROM: Daniele B Malesani at DTU Space J. P. U. Fynbo (DAWN/NBI), D. A. Perley (LJMU), A. de Ugarte Postigo (HETH/IAA-CSIC; DARK/NBI), D. B. Malesani (DTU Space), N. E. Jannsen (NOT), report on behalf of a larger collaboration: Spectroscopy was secured of the optical counterpart (Reva et al., GCN 26036; Perley et al., GCN 26039) of GRB 191019A (Simpson et al., GCN 26031), using the ALFOSC instrument mounted on the Nordic Optical Telescope (NOT). Observations started on 2019 Oct 19.873 UT (5.74 hr after the GRB), for a total of 2x1800 s exposure. Our spectrum, secured with grism #4, covers the approximate wavelength range 3500-9400 AA. The continuum is well detected. No prominent emission lines are visible. However, several absorption features can be identified, including Ca H & K, Na I D, Hdelta, Hgamma, Hbeta, G band, all at a common redshift z = 0.248. The 4000 AA break is also present. The spectrum is typical of an old stellar population, and is unlike that of long-duration GRB host galaxies. The association of this object with GRB 191019A is therefore unclear. Using the formula by Bloom et al. (2002, AJ, 123, 1111), the chance association probability for a source with magnitude r = 19.14 AB (from the Pan-STARRS catalog) and an error circle radius of 3.1" (Evans et al., GCN 26034) is approximately 3*10^-3. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26042 SUBJECT: GRB 191019A: GROND observations DATE: 19/10/20 13:43:49 GMT FROM: Ana Nicuesa at TLS Tautenburg A. Nicuesa Guelbenzu (TLS Tautenburg) reports: GROND (Greiner et al. 2008, PASP 120, 405) performed a first visit of the field of GRB 191019A (Swift trigger 930285; Simpson et al., GCN 26031) at 01:35 UT on 2019-10-20, about 10.3 hours after the burst. Observations were performed at an airmass of 1.02 and a seeing of 2.0 arcsec. Second-epoch observations started at 05:10 UT on the same night (airmass 1.75, seeing 1.7 arcsec). The potential afterglow plus host-galaxy complex is clearly detected. Between the 1st and the 2nd-epoch observations there is no evidence for fading in any band (g'r'i'z' as well as in JHKs). The GROND r'(AB = 19.14 +/- 0.01) and i' (AB = 18.73 +/- 0.01) magnitudes are in agreement with the NOT observations and the Pan-STARRS catalog (Perley et al., GCN 26039; Fynbo et al., GCN 26041). I acknowledge the excellent support from Sam Kim on La Silla in acquiring these observations //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26043 SUBJECT: GRB 191019A: Enhanced Swift-XRT position DATE: 19/10/20 15:06:57 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 616 s of XRT Photon Counting mode data and 2 UVOT images for GRB 191019A, 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 = 340.02470, -17.32803 which is equivalent to: RA (J2000): 22h 40m 5.93s Dec (J2000): -17d 19' 40.9" with an uncertainty of 2.4 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 was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26044 SUBJECT: Swift GRB191019.67: Global MASTER-Net observations report DATE: 19/10/20 15:22:08 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB191019.67 (trigger No 930285,22h 40m 05.760s , -17d 19m 44.40s, R=0.001) errorbox 3218 sec after notice time and 38 sec after trigger time at 2019-10-19 16:07:27 UT, with upper limit up to 18.9 mag. The observations began at zenit distance = 65 deg. The sun altitude is -19.8 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1171626 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 129 | MASTER-Kislovodsk | P- | 180 | 18.1 | 129 | MASTER-Kislovodsk | P| | 180 | 18.3 | 344 | MASTER-Kislovodsk | P- | 180 | 18.3 | 548 | MASTER-Kislovodsk | P- | 180 | 18.3 | 548 | MASTER-Kislovodsk | P| | 180 | 18.4 | 753 | MASTER-Kislovodsk | P| | 180 | 18.3 | 753 | MASTER-Kislovodsk | P- | 180 | 18.3 | 958 | MASTER-Kislovodsk | P- | 180 | 18.2 | 958 | MASTER-Kislovodsk | P| | 180 | 18.6 | 1162 | MASTER-Kislovodsk | P| | 180 | 18.7 | 1162 | MASTER-Kislovodsk | P- | 180 | 18.3 | 1366 | MASTER-Kislovodsk | P- | 180 | 18.3 | 1366 | MASTER-Kislovodsk | P| | 180 | 18.5 | 1576 | MASTER-Kislovodsk | P- | 180 | 18.3 | 1576 | MASTER-Kislovodsk | P| | 180 | 18.8 | 1781 | MASTER-Kislovodsk | P- | 180 | 18.3 | 1781 | MASTER-Kislovodsk | P| | 180 | 18.7 | 1985 | MASTER-Kislovodsk | P- | 180 | 18.3 | 1985 | MASTER-Kislovodsk | P| | 180 | 18.7 | 2190 | MASTER-Kislovodsk | P| | 180 | 18.7 | 2190 | MASTER-Kislovodsk | P- | 180 | 18.3 | 2395 | MASTER-Kislovodsk | P- | 180 | 18.5 | 2395 | MASTER-Kislovodsk | P| | 180 | 18.7 | 2599 | MASTER-Kislovodsk | P- | 180 | 18.4 | 2599 | MASTER-Kislovodsk | P| | 180 | 18.9 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26045 SUBJECT: GRB 191019A: Swift-XRT refined Analysis DATE: 19/10/20 15:32:57 GMT FROM: Phil Evans at U of Leicester A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), J. D. Gropp (PSU), A. Tohuvavohu (U. Toronto), J.A. Kennea (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and K.K. Simpson report on behalf of the Swift-XRT team: We have analysed 3.9 ks of XRT data for GRB 191019A (Simpson et al. GCN Circ. 26031), from 3.3 ks to 17.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 26043). The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00930285. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26046 SUBJECT: GRB 191019A: Swift-BAT refined analysis DATE: 19/10/20 16:54:32 GMT FROM: Amy Lien at GSFC H. A. Krimm (NSF), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), K. K. Simpson (PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 191019A (trigger #930285) (Simpson et al., GCN Circ. 26031). The BAT ground-calculated position is RA, Dec = 340.035, -17.340 deg which is RA(J2000) = 22h 40m 08.3s Dec(J2000) = -17d 20' 23.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%. The mask-weighted light curve shows a complex structure with many overlapping pulses that starts at ~T0 and ends at ~T+90 s. The burst went out of the BAT FOV at ~T+400 s. T90 (15-350 keV) is 64.35 +- 4.45 sec (estimated error including systematics). The time-averaged spectrum from T-0.83 to T+84.28 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.25 +- 0.05. The fluence in the 15-150 keV band is 1.0 +- 0.03 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T-0.14 sec in the 15-150 keV band is 5.7 +- 0.4 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/930285/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26048 SUBJECT: GRB 191019A: Swift-XRT updated analysis DATE: 19/10/20 20:12:27 GMT FROM: Boris Sbarufatti at PSU B. Sbarufatti (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and K.K. Simpson (PSU) report on behalf of the Swift-XRT team: We have analyzed 8.5 ks of XRT data for GRB 191019a (Simpson et al. GCN Circ. 26031), from 3.3 ks to 32.4 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 26043). The light curve can be modeled with a power-law decay with a decay index of alpha=1.0 (+/-0.2). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+/- 0.40). The best-fitting absorption column is consistent with the Galactic value of 3.3 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 3.4 x 10^-11 (4.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total intrinsic column: < 2.23 x 10^21 cm^-2 Galactic foreground: 3.3 x 10^20 cm^-2 Photon index: 2.0 (+/- 0.4) If the light curve continues to decay with a power-law decay index of 1.0, the count rate at T+48 hours will be 1.2 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.1 x 10^-14 (4.9 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00930285/. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26053 SUBJECT: GRB 191019A: Swift/UVOT Detection DATE: 19/10/21 22:05:22 GMT FROM: Sam LaPorte at PSU GRB 191019A: Swift/UVOT Detection S. J. LaPorte (PSU) and K. K. Simpson (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 191019A 3294 s after the BAT trigger (Simpson et al., GCN Circ. 26031). A fading source consistent with the XRT position (Evans et al. GCN Circ. 26034) is detected in the initial UVOT exposures. Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag b 4541 4741 196 19.55+-0.30 uvm2 5361 5561 196 >19.20 u 4336 4536 196 >19.43 v 5156 5356 196 >18.75 uvw1 4131 4331 196 >19.13 uvw2 4952 5151 196 >19.28 white 4746 4946 196 19.66+-0.20 white 27982 28668 668 20.27+-0.18 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). Additionally, these magnitudes likely include a contribution from the probable host-galaxy, as reported by TSHAO (Reva et al., GCN Circ. 26036), NOT (Fynbo et al., GCN Circ. 26041), and GROND (Guelbenzu et al. GCN Circ. 26042). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26059 SUBJECT: GRB 191019A: Nanshan-0.6m optical observations DATE: 19/10/22 13:58:53 GMT FROM: Dong Xu at NAOC/CAS Z.P. Zhu, B.Y. Yu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School) report: We observed the field of GRB 191019A (Simpson et al., GCN 26031) using the 0.6m NEXT telescope located at Nanshan, Xinjiang, China. Observations started at 15:34:01 UT (i.e., 21.5 min after the BAT trigger) and ended at 18:22:51 UT on 2019-10-19, and a series of 60 s, 200 s, 300 s Sloan r-band frames were obtain in a high airmass. A source is detected in our images at the XRT position (Osborne et al., GCN 26043), which is already present in Pan-STARRS with m(r) = 19.12 +/- 0.01. The source had m(r) = 18.96 +/- 0.10 at the beginning and decayed to m(r) = 19.19 +/- 0.10 in about an hour. Because the flux difference is small and observations were carried out in high airmass, it's not clear if there is a GRB afterglow contribution. Our measurements are in agreement with that by NOT (Perley et al., GCN 26039; Fynbo et al., GCN 26041) and GROND (Guelbenzu et al., GCN 26042). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26062 SUBJECT: GRB 191019A: NOT optical afterglow and host association confirmation DATE: 19/10/23 21:55:37 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU), D. B. Malesani (DTU Space), A. J. Levan (Radboud Univ.), J. P. U. Fynbo (DAWN/NBI), and A. A. Djupvik (NOT) report on behalf of a larger collaboration: We obtained additional observations of the optical counterpart (Reva et al., GCN 26036; LaPorte & Simpson, GCN 26053; Zhu et al., GCN 26059) of GRB 191019A (Simpson et al., GCN 26031), using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. A total of 25 minutes exposure was secured with mid time Oct 22.875 UT (77.8 hr after the GRB). The archival object consistent with the XRT error circle is well detected, with a magnitude of i = 18.71 +/- 0.02 AB, consistent with the Pan-STARRS tabulated value of i = 18.71 +/- 0.01 and slightly fainter than our earlier observation (Perley et al., GCN 26039), for which the mid time was 4.60 hr after the GRB. Digital image subtraction was carried out with ISIS (Alard 2000, A&AS, 144, 363) between the two epochs. A clear point-like residual is detected, for which we measure a magnitude i = 21.78 +/- 0.05 AB (assuming no residual flux in our second epoch). Its position calibrated against the Gaia catalog is: RA(J2000) = 22:40:05.89 Dec(J2000) = -17:19:42.6 (+/- 0.3") An image showing the subtraction result is available here: http://outer.space.dtu.dk/~dmales/GRB/191019A/subtraction.jpg The transient location is 0.07" east of the galaxy nucleus, strengthening the case for a physical association between the two objects. The offset is within the margin of error, although the NOT spectroscopy (Fynbo et al., GCN 26041) does not suggest that the source is an AGN. Our observations thus confirm the presence of a transient optical source at a position consistent with the X-ray afterglow, located to within the errors on top of the nucleus of the candidate host. The lack of any non-obscured star formation makes this system unique among long-duration GRBs. We encourage observations of this puzzling source at all wavelengths. DisclaimerNone //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26098 SUBJECT: GRB 191019A: Zadko Telescope optical observations DATE: 19/10/30 05:46:27 GMT FROM: Bruce Gendre at UVI B. Gendre (OzGrav-UWA), H. Crisp (OzGrav-UWA), D. Coward (OzGrav-UWA), J. Zadko (Claire Energy), J. A. Moore (OzGrav-UWA), A. Burrell (OzGrav-UWA), A. Klotz (IRAP-OMP-UPS), P. Thierry (Auragne Observatory), E.J. Howell (OzGrav-UWA), A. Verveer (ASA), J. Kennewell (UWA, ASA) report: We observed GRB 191019A (Simpson et al., GCN 26031) with the Zadko Telescope (Coward et al. 2017), starting at 2019 October the 19th at 15:20:23 UT (7 minutes 50 seconds after the trigger) under fair conditions. The object reported by Reva et al. (GCN 26036) is clearly visible in our images. However, we measure an R magnitude of 18.92 at the time reported by the GCN. Observations stopped one hour twenty three minutes after the burst, and during that time we do not see any variation on the light curve, similar to other teams (Perley et al., GCN 26039; Fynbo et al., GCN 26041; and Zhu et al., GCN 26059). At that position, the USNO catalog reports a source of magnitude R = 19.0, consistent with our findings. We conclude that this object is not the afterglow of GRB 191019A, but the host galaxy, as reported by Perley et al. (GCN 26062). The Zadko Telescope has been under refurbishment during the last year, and is still in recommissioning mode. This message can be cited. -- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. https://www.avast.com/antivirus