GRB200412B

This page lists all entries on GRB200412B in GRBweb

Summary Fermi GBM IPN GCN 27547 GCN 27548 GCN 27549 GCN 27551 GCN 27553 GCN 27555 GCN 27556 GCN 27557 GCN 27558 GCN 27561 GCN 27563 GCN 27564 GCN 27565 GCN 27566 GCN 27567 GCN 27570 GCN 27571 GCN 27572 GCN 27574 GCN 27575 GCN 27576 GCN 27581 GCN 27582 GCN 27583 GCN 27593 GCN 27598 GCN 27600 GCN 27604 GCN 27605 GCN 27610 GCN 27653

Summary table
Variable Value Source
GRB_name_Fermi GRB200412381
T0 9:08:40 UTC GCN_circulars,Fermi GBM final loc
ra 277.4792° IPN
decl 61.7833° IPN
pos_error 5.00e-01° IPN
T90 6.08 s Fermi_GBM
T90_error 0.286 s Fermi_GBM
T90_start 9:08:45.891 UTC Fermi_GBM
fluence 7.25e-05 erg/cm² Fermi_GBM
fluence_error 3.46e-07 erg/cm² Fermi_GBM
T100 11.971 s
GBM_located False
mjd 58951.38101851852 GCN_circulars,Fermi GBM final loc
Fermi GBM table
GRB_name_Fermi GRB200412381
trigger_name bn200412381
ra 277.4800°
decl 61.7900°
pos_error 2.45e+00°
datum 2020-04-12
t_trigger 9:08:40.707 UTC
T90 6.08 s
T90_error 0.286 s
T90_start 9:08:45.891 UTC
fluence 7.25e-05 erg/cm²
fluence_error 3.46e-07 erg/cm²
flux_1024 1.25e+02 erg/cm²/s
flux_1024_error 6.67e-01 erg/cm²/s
flux_1024_time 9.09e+00 erg/cm²/s
flux_64 1.66e+02 erg/cm²/s
flux_64_error 3.04e+00 erg/cm²/s
IPN table
GRB_name GRB200412B
ra 277.4792°
decl 61.7833°
pos_error 5.00e-01°
GCN 27547 table
GRB_name GRB200412B
GCN_number 27547
Detection_method Fermi GBM final loc
t_trigger 9:08:40 UTC
ra 279.8000°
decl 64.1000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27547 SUBJECT: GRB 200412B: Fermi GBM Final Real-time Localization DATE: 20/04/12 09:18:58 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 09:08:40 UT on 12 Apr 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200412B (trigger 608375325.70677 / 200412381). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 279.8, Dec = 64.1 (J2000 degrees, equivalent to J2000 18h 39m, 64d 05'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 57.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200412381/quicklook/glg_skymap_all_bn200412381.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200412381/quicklook/glg_healpix_all_bn200412381.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200412381/quicklook/glg_lc_medres34_bn200412381.gif
GCN 27548 table
GRB_name GRB200412B
GCN_number 27548
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27548 SUBJECT: GRB 200412B: BALROG localization (Fermi Trigger 608375325 / GRB 200412381) DATE: 20/04/12 09:45:13 GMT FROM: Jochen Greiner at MPE,Garching J. Burgess, B. Biltzinger, F. Kunzweiler, F. Berlato & J. Greiner (all MPE Garching) report: We note that the spectral fit from the automated pipeline appears off due to more high-energy emission than normal. We are re-running the pipeline manually to test this hypothesis. This position may be updated. The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 608375325 at 09:08:40 on 12 April 2020 were automatically fitted for spectrum and sky location with the official BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 271.0+/-1.1 deg Decl.(2000.0) = 64.4+/-0.3 deg We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB200412381/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB200412381/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB200412381/json
GCN 27549 table
GRB_name GRB200412B
GCN_number 27549
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27549 SUBJECT: Fermi GRB 200412B: Global MASTER-Net observations report DATE: 20/04/12 12:00:09 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, D. Cheryasov (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-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 200412B ( Fermi GBM team, GCN 27547) errorbox 8581 sec after notice time and 8607 sec after trigger time at 2020-04-12 11:32:08 UT, with upper limit up to 18.1 mag. Observations started at twilight. The observations began at zenith distance = 62 deg. The sun altitude is -11.6 deg. The galactic latitude b = 21 deg., longitude l = 93 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1334873 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 8638 | 2020-04-12 11:32:08 | MASTER-Amur | (18h 42m 54.00s , +64d 01m 02.2s) | C | 60 | 17.7 | 8717 | 2020-04-12 11:33:27 | MASTER-Amur | (18h 36m 40.79s , +62d 00m 23.4s) | C | 60 | 17.7 | 8876 | 2020-04-12 11:36:06 | MASTER-Amur | (18h 51m 29.33s , +66d 00m 50.1s) | C | 60 | 17.8 | 8955 | 2020-04-12 11:37:26 | MASTER-Amur | (18h 42m 48.05s , +64d 01m 55.3s) | C | 60 | 18.1 | 9036 | 2020-04-12 11:38:46 | MASTER-Amur | (19h 01m 08.17s , +64d 00m 49.8s) | C | 60 | 17.9 | 9115 | 2020-04-12 11:40:06 | MASTER-Amur | (18h 36m 35.84s , +61d 59m 55.8s) | C | 60 | 18.0 | 9195 | 2020-04-12 11:41:25 | MASTER-Amur | (18h 53m 41.44s , +62d 00m 17.0s) | C | 60 | 17.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 27551 table
GRB_name GRB200412B
GCN_number 27551
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27551 SUBJECT: GRB 200412B: Tiled Swift observations DATE: 20/04/12 14:37:38 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 200412B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00089 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: 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 OPS NOTE(12apr20): The "C" on the GRN name in the Subject-line and in the first sentence has been changed to the correct "B" designation.]
GCN 27553 table
GRB_name GRB200412B
GCN_number 27553
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27553 SUBJECT: Correction to GCN 27551 - Swift is observing GRB 200412*B* DATE: 20/04/12 15:26:08 GMT FROM: Phil Evans at U of Leicester Phil Evans & Kim Page (U. Leicester) report on behalf of the Swift team. There was an error in GRB name given in GCN Circ 27551; Swift has in fact begun observations of GRB 200412B, rather than (as yet) non-existent GRB 200412C. We apologise for the confusion.
GCN 27555 table
GRB_name GRB200412B
GCN_number 27555
Detection_method Other
ra 278.3139°
decl 62.5325°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27555 SUBJECT: GRB 200412B: MASTERt Optical Couterpart in Gagarin day! DATE: 20/04/12 15:28:52 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov (Lomonosov MSU) and V. Yurkov, A. Gabovich, Yu. Sergienko( [BBlagoveschensk Educational State University) 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), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), 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), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) MASTER OT J111012.51+274912.8 discovery - new OT inside Fermi GRB 200325B (trigger 606840801). MASTER-Amur auto-detection system ( located near Russia Kosmodrom Vostochniy) discovered OT source at (RA, Dec) = 18h 33m 15.33s +62d 31m 57.0s on 2020-04-12.48156 UT in Fermi error box (GCN 27547, 27548) Lipunov et al., GCN 27549). The OT unfiltered magnitude is 16.6m (mlim18.0). The OT is seen in 2 images. There is no minor planet at this place. We have reference image on 2016-08-12.64123 UT with unfiltered mlim= 19.3m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/183315.33623157.0.png
GCN 27556 table
GRB_name GRB200412B
GCN_number 27556
Detection_method Optical
ra 278.3139°
decl 62.5325°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27556 SUBJECT: GRB 200412B: MASTER-Amur Optical Couterpart in Gagarin day! DATE: 20/04/12 15:47:07 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov (Lomonosov MSU) and V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) 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), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), 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), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) MASTER-Amur ( located near Russian Kosmodrom Vostochniy) comeback to MASTER OT J111012.51+274912.8 (Lipunov et al., GCN 27555) after 2 hours and we find optical transient with limit ~ 17.5 . So this is real afterglow: at (RA, Dec) = 18h 33m 15.33s +62d 31m 57.0s on The OT is seen in 2 images. There is no minor planet at this place. We have reference image on 2016-08-12.64123 UT with unfiltered mlim= 19.3m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/183315.33623157.0.png
GCN 27557 table
GRB_name GRB200412B
GCN_number 27557
Detection_method Fermi LAT Det
t_trigger 9:08:40 UTC
ra 277.4800°
decl 61.7900°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27557 SUBJECT: GRB 200412B: Fermi-LAT detection DATE: 20/04/12 15:53:48 GMT FROM: Francesco Longo at U of Trieste,INFN Trieste F. Longo (University & INFN Trieste), D.Kocesvki (NASA/MSFC), E.Bissaldi (Politecnico and INFN, Bari), M.Ohno (Hiroshima University) and M.Palatiello (University of Udine & INFN, Trieste) report on behalf of the Fermi-LAT Collaboration: On April 12, 2020, Fermi-LAT detected high-energy emission from GRB 200412B, which was also detected by Fermi-GBM (trigger 608375325/200412381). The best LAT on-ground location is found to be RA, Dec = 277.48, 61.79 (degrees, J2000) with an error radius of 0.5 deg (90% containment, statistical error only). This was 59 deg from the LAT boresight at the time of the GBM trigger: T0 = 09:08:40 UT. The data from the Fermi-LAT show a significant increase in the event rate after the GBM trigger that is spatially correlated with the GBM emission (2.6 degrees from the GBM position) with high significance. The photon flux above 100 MeV in the time interval 0-1000 s after the GBM trigger is 6.0 +/- 1.6 e-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.9 +/- 0.4 The highest-energy photon is a 1.1 GeV event which is observed 134 seconds after the GBM trigger. A Swift ToO has been requested for this burst. The Fermi-LAT point of contact for this burst is Michele Palatiello (michele.palatiello@gmail.com) 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 27558 table
GRB_name GRB200412B
GCN_number 27558
Detection_method Fermi GBM Det
t_trigger 9:08:40.710 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 27558 SUBJECT: GRB 200412B: Fermi GBM detection DATE: 20/04/12 17:23:16 GMT FROM: Rachel Hamburg at UAH B. Mailyan (Institute for Basic Science, South Korea) and R. Hamburg (UAH) report on behalf of the Fermi GBM Team: "At 09:08:40.71 UT on 12 April 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200412B (trigger 608375325 / 200412381), which was also detected by the Fermi LAT (Longo et al. 2020, GCN 27557) and observed to have a candidate optical afterglow by MASTER (GCN 27555 & GCN 27556). The GBM on-ground location is consistent with the LAT position. The angle from the Fermi LAT boresight at the GBM trigger time is 59 degrees. The GBM light curve shows a multi-peaked structure with a duration (T90) of about 6 s (50-300 keV). The time-averaged spectrum from T0+3.1s to T0+21.5 s is best fit by a Band function with Epeak = 257 +/- 4 keV, alpha = -0.54 +/- 0.01, and beta = -2.24 +/- 0.02. The event fluence (10-1000 keV) in this time interval is (8.00 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+9.1 s in the 10-1000 keV band is 127.5 +/- 0.7 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN 27561 table
GRB_name GRB200412B
GCN_number 27561
Detection_method Swift-XRT Other
ra 278.3134°
decl 62.5325°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27561 SUBJECT: GRB 200412B: Swift-XRT afterglow detection DATE: 20/04/12 23:35:46 GMT FROM: Boris Sbarufatti at PSU K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (ASDC), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (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 200412B (Longo et al. GCN Circ. 27557) in a series of observations tiled on the sky. The total exposure time is 4.9 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 1.5 ks. The data were collected between T0+20.1 ks and T0+31.7 ks, and are entirely in Photon Counting (PC) mode. Two uncatalogued X-ray sources are detected, of which one ("Source 2") is above the RASS limit, and is therefore likely the GRB afterglow. Using 671 s of PC mode data and 2 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 = 278.31339, +62.53253 which is equivalent to: RA (J2000): 18h 33m 15.21s Dec(J2000): +62d 31' 57.1" with an uncertainty of 2.5 arcsec (radius, 90% confidence). This position is 30.1 arcmin from the Fermi/LAT position. The light curve can be modelled with a power-law decay with a decay index of alpha=1.9 (+1.3, -1.2). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.8 (+0.6, -0.5). The best-fitting absorption column is 1.6 (+1.8, -1.0) x 10^21 cm^-2, consistent with the Galactic value of 5.1 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 3.1 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.6 (+1.8, -1.0) x 10^21 cm^-2 Galactic foreground: 5.1 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.8 (+0.6, -0.5) If the light curve continues to decay with a power-law decay index of 1.9, the count rate at T+24 hours will be 0.015 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.7 x 10^-13 (5.8 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis of the likely afterglow are at https://www.swift.ac.uk/xrt_products/TILED_GRB00089/Source2.php. The results of the full analysis of the tiled XRT observations are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00089. This circular is an official product of the Swift-XRT team.
GCN 27563 table
GRB_name GRB200412B
GCN_number 27563
Detection_method AstroSat CZTI
Circular_text TITLE: GCN CIRCULAR NUMBER: 27563 SUBJECT: GRB 200412B : AstroSat CZTI detection DATE: 20/04/13 08:06:48 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT S. Gupta, V. Sharma, A. Vibhute 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 GRB 200412B, which was also detected by Fermi GBM Final Real-time (GCN #27547), BALROG (Burgess J. et al., GCN #27548), Global MASTER-Net (Lipunov V. et al, GCN #27549), Tiled Swift (Evans P. et al., GCN #27551), Fermi-LAT (Longo F. et al., GCN #27557), Fermi GBM (Mailyan B. et al., GCN #27558) and Swift-XRT (Page K. et al., GCN #27561). The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission peaking at 2020-04-12 09:08:49.5 UT. The measured peak count rate associated with the burst is 1160 +/- 40.72 cts/s above the background in the combined data of four quadrants, with a total of 3452 +/- 16.55 cts. The local mean background count rate was 519 +/- 0.87 cts/s. Using cumulative rates, we measure a T90 of 7.17 +/- 0.06 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 27564 table
GRB_name GRB200412B
GCN_number 27564
Detection_method Fermi GBM Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 27564 SUBJECT: GRB 200412B: Optical afterglow detection with 1.3m DFOT DATE: 20/04/13 09:14:18 GMT FROM: Amit Kumar at ARIES, India TITLE: GCN CIRCULAR NUMBER: 27563 SUBJECT: GRB 200412B: Optical afterglow detection with 1.3m DFOT DATE: 20/04/13 09:05:41 GMT FROM: Amit Kumar at ARIES, India A. Kumar (ARIES), A. Aryan (ARIES), S. B. Pandey (ARIES), S. Mishra (ARIES), R. Gupta (ARIES), A. Ghosh (ARIES), Dimple (ARIES), and K. Misra (ARIES) report: We observed the optical afterglow of the Fermi GBM detected GRB 200412B (GCN 27547, Lipunov et al., GCN 27555, GCN 27561) with the 1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (India), from 2020-04-12 UT 22:03:14 to 2020-04-12 UT 23:29:44 (corresponding to 12.90 to 14.46 hours from the GRB trigger time). We observed a series of 9x300s exposures in Bessel R filter and a series of 7x360s exposures in Bessel I filter. We stacked the images and detected the optical afterglow of GRB 200412B in both Bessel R and I filters which is consistent with optical detections by Lipunov et al., GCN 27555, 27556. The observed magnitudes are as follows: T_start-T0 (hours) Start Date (UTC) End Date (UTC) Filter Magnitudes --------------------------------------------------------------------------------------------------------------- 12.90 2020-04-12 UT 22:03:14 2020-04-12 UT 22:46:11 R 18.90 +- 0.03 13.72 2020-04-12 UT 22:52:02 2020-04-12 UT 23:29:44 I 17.54 +- 0.02 Photometry is done based on the USNO-B1.0 catalog. The quoted magnitudes are not corrected for Galactic extinction.
GCN 27565 table
GRB_name GRB200412B
GCN_number 27565
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27565 SUBJECT: GRB 200412B: Insight-HXMT/HE detection DATE: 20/04/13 09:40:36 GMT FROM: YaoGuang Zheng at IHEP Y. G. Zheng, C. Cai, Y. F. Du, W. C. Xue, Q. Luo, S. Xiao, Q. B. Yi, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2020-04-12T09:08:45.80 (T0), Insight-HXMT/HE detected GRB 200412B (trigger ID: HEB200412381) in a routine search of the data, which also triggered Fermi/GBM (GCN #27547). The Insight-HXMT/HE light curve mainly consists of a single pulse with a duration (T90) of 5.50 s measured from T0+0.05 s. The 1-ms peak rate, measured from T0+4.28 s, is 14908 cnts/sec. The total counts from this burst is 25230 counts. URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB200412381_lc.jpg All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org.
GCN 27566 table
GRB_name GRB200412B
GCN_number 27566
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27566 SUBJECT: GRB 200412B: AbAO optical observations DATE: 20/04/13 10:09:07 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), V.R. Ayvazian (AbAO), G. V. Kapanadze (AbAO), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of GRB IKI FuN: We observed the field of Fermi GRB 200412B (Fermi GBM team GCN 27547; Longo et al., GCN 27557) with AS-32 (0.7m) telescope of Abastumani Observatory starting on 2020-04-12 (UT) 18:42:21. We detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555; Kumar et al., GCN 27564). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2020-04-12 18:42:21 0.41783 R 56*60 18.31 0.02 21.3 The photometry is based on nearby USNO-B1.0 stars UUSNO-B1.0_id R2 1525-0302108 17.21 1524-0300914 17.20 1525-0301929 17.85 [GCN OPS NOTE(13apr20): Removed the extra "GRB" in the SUBJECT-line.]
GCN 27567 table
GRB_name GRB200412B
GCN_number 27567
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27567 SUBJECT: GRB 200412B: Tautenburg observations DATE: 20/04/13 12:26:07 GMT FROM: Sylvio Klose at TLS Tautenburg B. Stecklum, S. Klose, S. Melnikov, and A. Nicuesa Guelbenzu (all Tautenburg) report: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB). The transmission curve of this filter closely follows the Gaia GBP filter. The fading optical transient detected by MASTER Global Robotic Net (Lipunov et al., GCN 27555, 27556) is clearly detected on our images (for other optical observations see also Kumar et al., GCN 27564; Belkin et al., GCN 27566). Using Gaia DR2 stars in the field, we measure the following preliminary magnitudes (Vega system): Mean time: April 12, 21:29:48 UT, VB = 18.43 +/- 0.01 Mean time: April 13, 02:22:38 UT, VB = 19.00 +/- 0.01
GCN 27570 table
GRB_name GRB200412B
GCN_number 27570
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27570 SUBJECT: GRB 200412B: SAO RAS observations of OT DATE: 20/04/14 01:54:38 GMT FROM: Moskvitin Alexander at SAO RAS A. Moskvitin on behalf of the larger GRB follow-up team report. We observed the field of the GRB 200412B (The Fermi GBM team, GCN 27547; Longo et al. GCN 27557) with the 1-m telescope of SAO RAS, equipped with the Multi-Mode Photometer-Polarimeter. We obtained 6 x 300 sec. images in Rc band on 2020.04.14 00:09:20--00:41:40 UT, T_mid - T0 = 1.6367 days. The OT (Lipunov et al., GCNs 27555, 27556; Kumar et al., GCN 27564; Belkin et al., GCN 27566) is clearly visible in individual images and stacked frame with the brightness of R = 20.8 +/- 0.1. The photometry is based on R2 magnitudes of nearby USNO-B1 stars.
GCN 27571 table
GRB_name GRB200412B
GCN_number 27571
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27571 SUBJECT: GRB 200412B: Xinglong TNT optical observations DATE: 20/04/14 04:22:19 GMT FROM: Liping Xin at NAOC, SVOM L. P. Xin, X. F. Wang, J. Zheng, Y. L. Qiu, J. Y. Wei, J. Wang, L. H. Li , C. Wu, X. H. Han and J. S. Deng, report: We began to observe GRB 200412B (The Fermi GBM team, GCN 27547; Longo et al. GCN 27557) with Xinglong TNT telescope at 18:09:54 (UT), 13th. Apr. 2020, about 33 hours after the burst. 10 x 300 sec R band images were obtained. The optical afterglow (Lipunov et al., GCNs 27555, 27556; Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570) is clearly detected in individual images with the brightness of R = 20.0 +/- 0.1. The photometry is based on R2 magnitudes of nearby USNO-B1 stars. With the reports from (Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570), the brightness is fading with a slope of -1.5 for a single power law (t~t^a) from 10 hours to 39 hours after the burst trigger.
GCN 27572 table
GRB_name GRB200412B
GCN_number 27572
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 27572 SUBJECT: GRB 200412B: CALET Gamma-Ray Burst Monitor detection DATE: 20/04/14 08:20:52 GMT FROM: Valentin Pal'shin at AGU T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The bright GRB 200412B (BALROG localization: Burgess et al., GCN Circ. 27548; Fermi-LAT detection: Longo et al., GCN Circ. 27557; Fermi GBM detection: Mailyan and Hamburg, GCN Circ. 27558; https://gcn.gsfc.nasa.gov/other/200412B.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 09:08:43.975 UTC on 12 April 2020. The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure which starts at T-0.3 sec, peaks at T+6.2 sec and ends at T+13.1 sec. The T90 and T50 durations measured by the SGM data are 6.1 +- 0.5 sec and 1.8 +- 0.1 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1270717362/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN 27574 table
GRB_name GRB200412B
GCN_number 27574
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27574 SUBJECT: GRB 200412B: contunued AbAO optical observations DATE: 20/04/14 10:19:21 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), V.R. Ayvazian (AbAO), G. V. Kapanadze (AbAO), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of GRB IKI FuN: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with AS-32 (0.7m) telescope of Abastumani Observatory starting on 2020-04-14 (UT) 00:16:57. We clearly detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555, 27556; Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570; Xin et al., GCN 27571). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2020-04-14 00:16:57 1.65401 R 67*60 20.7 0.1 22.1 The photometry is based on nearby USNO-B1.0 stars UUSNO-B1.0_id R2 1525-0302108 17.21 1524-0300914 17.20 1525-0301929 17.85 The index of power law decay of the afterglow light curve between the two epochs of our observations (Belkin et al., GCN 27566 at 0.41793 days) and reported in this circular (at 1.65401 days) is -1.58+/-0.07 which is corroborate with the index reported by Xin et al. (GCN 27571).
GCN 27575 table
GRB_name GRB200412B
GCN_number 27575
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27575 SUBJECT: GRB 200412B: Tautenburg observations DATE: 20/04/14 10:45:57 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose, B. Stecklum, S. Melnikov, and A. Nicuesa Guelbenzu (all Tautenburg) report: We continued observing the field of GRB 200412B (Fermi GBM team, GCN 27547) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB; Stecklum et al., GCN 27567). For the optical transient (Lipunov et al., GCN 27555, 27556) at a mean time APR 13, 21:08:59 UT (1.500 days post burst) we measure VB = 20.27 +/- 0.03. Compared to our 1st-epoch observations (dt=0.51 days; Stecklum et al., GCN 27567) this provides a decay slope of alpha = 1.58 (F\nu \propto t**(-\alpha)), in agreement with the results reported by Xin et al. (GCN 27571) and Belkin et al. (GCN 27574).
GCN 27576 table
GRB_name GRB200412B
GCN_number 27576
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 27576 SUBJECT: GRB 200412B: MITSuME Akeno optical observation DATE: 20/04/14 11:52:40 GMT FROM: Ogawa Futa at Tokyo Institute of Technology F. Ogawa, R. Adachi, R. Hosokawa, K. L. Murata, M. Niwano, N. Nakamura, Y. Yatsu, and N. Kawai(TokyoTech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 200412B (The Fermi GBM team, GCN Circular #27547) 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 2020-04-13 15:27:09 UT. We detected the point source at the position consistent with the afterglow detected previously (E. Gorbovskoy et al. GCN #27555). We measured the magnitudes as follows. T0+[hour] MID-UT T-EXP[sec] measured magnitudes ------------------------------------------------------------------------------------------------ 30.2 2020-04-13 17:19:02 10800 g'=20.1+/-0.2,Rc=19.6+/-0.2,Ic=19.5+/-0.2 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration. The magnitudes are expressed in the Vega system.
GCN 27581 table
GRB_name GRB200412B
GCN_number 27581
Detection_method Konus-Wind Det
t_trigger 9:08:44.203 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 27581 SUBJECT: Konus-Wind observation of GRB 200412B DATE: 20/04/15 09:16:05 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 200412B (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 27547; Mailyan and Hamburg, GCN Circ. 27558; BALROG localization: Burgess et al., GCN Circ. 27548; Fermi-LAT detection: Longo et al., GCN Circ. 27557; AstoSat CZTI detection: Gupta et al., GCN Circ. 27563; Insight-HXMT/HE detection: Zheng et al., GCN Circ. 27565; CALET-GRBM detection: Tamura et al., GCN Circ. 27572) triggered Konus-Wind at T0=32924.203 s UT (09:08:44.203). The burst light curve shows a multipeaked structure which starts at ~T0-0.5 s and has a total duration of ~30.5 s. The emission is seen up to ~6 MeV. As observed by Konus-Wind, the burst had a fluence of 1.12(-0.05,+0.05)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+5.744 s, of 5.12(-0.43,+0.44)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+15.360 s) is best fit in the 20 keV - 6 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.67(-0.05,+0.05), the high energy photon index beta = -2.45(-0.12,+0.10), the peak energy Ep = 289(-16,+16) keV (chi2 = 66/79 dof). The spectrum near the maximum count rate (measured from T0+5.376 to T0+5.888 s) is best fit in the 20 keV - 6 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.15(-0.10,+0.11), the high energy photon index beta = -2.58(-0.17,+0.14), the peak energy Ep = 316(-24,+24) keV (chi2 = 56/56 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB200412_T32924/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 27582 table
GRB_name GRB200412B
GCN_number 27582
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27582 SUBJECT: GRB 200412B: continued Tautenburg observations DATE: 20/04/15 09:30:32 GMT FROM: Sylvio Klose at TLS Tautenburg B. Stecklum, S. Klose, S. Melnikov, and A. Nicuesa Guelbenzu (all Tautenburg) report: We continued observing the field of GRB 200412B (Fermi GBM team, GCN 27547) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB; Stecklum et al., GCN 27567; Klose et al., GCN 27575). For the optical transient (Lipunov et al., GCN 27555, 27556) at a mean time of 2.521 days post burst we measure VB = 21.38 +/- 0.06. This is about 0.2 mag fainter than expected for a decay slope of alpha = 1.582 +/- 0.004 based on our previous VB-band data (see also Xin et al., GCN 27571; Belkin et al., GCN 27574), suggesting that the light curve decay is steepening. Additional data are required to confirm (or reject) this conclusion. We note that in our images there is still no evidence for an underlying host galaxy.
GCN 27583 table
GRB_name GRB200412B
GCN_number 27583
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27583 SUBJECT: GRB 200412B: Mondy optical observations DATE: 20/04/15 10:11:58 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), M. Eselevich (ISTP), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB FuN: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with AZT-33IK 1.5-m telescope of Sayan observatory (Mondy) starting on 2020-04-14 (UT) 14:24:54. We clearly detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555, 27556; see also Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570; Xin et al., GCN 27571). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2020-04-14 14:24:54 2.23002 R 15*120 21.22 0.08 22.8 The photometry is based on nearby USNO-B1.0 stars UUSNO-B1.0_id R2 1525-0302108 17.21 1524-0300914 17.20 1525-0301929 17.85
GCN 27593 table
GRB_name GRB200412B
GCN_number 27593
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27593 SUBJECT: GRB 200412B: continued Tautenburg observations DATE: 20/04/16 14:25:46 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose, B. Stecklum, S. Melnikov, and A. Nicuesa Guelbenzu (all Tautenburg) report: We continued observing the field of GRB 200412B (Fermi GBM team, GCN 27547) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB; Stecklum et al., GCN 27567, 27582; Klose et al., GCN 27575). For the optical transient (Lipunov et al., GCN 27555, 27556) at a mean time of 3.53 days post burst we measure VB = 22.29 +/- 0.11. This confirms the suspected steepening of the light curve decay (Stecklum et al., GCN 27582). Our present VB-band data imply alpha2 = 2.52 +/- 0.02 and a break time of 2.04 +/- 0.02 days.
GCN 27598 table
GRB_name GRB200412B
GCN_number 27598
Detection_method Fermi GBM Other
ra 278.3139°
decl 62.5325°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27598 SUBJECT: GRB200412B: GROWTH India detection of afterglow DATE: 20/04/17 06:59:26 GMT FROM: Varun Bhalerao at Indian Inst of Tech H. Kumar, M. Khandagale, K. Deshmukh, V. Bhalerao(IITB), G. C. Anupama, B. Kumar, A. Singh, A. Dutta, S. Barway(IIA), P. Dorji (IAO), U. Stanzin (IAO), report on behalf of the GROWTH collaboration: We observed GRB200412B reported by Fermi GBM Team (GCN 27547) and Burgess J. et al, (GCN 27548) with 0.7m robotic GROWTH-India telescope. We switched from tiled observations to targeted follow-up based on the afterglow identification by Lipunov V. et al, (GCN 27555) at RA(J2000) = 18:33:15.33 Dec(J2000) = +62:31:57.0 . The field was observed multiple times in g and r filters with 550 sec exposure time, starting about 7.4 hours after the trigger. We clearly detect the afterglow emission. The decay is well-described by a power law with alpha = 1.05 +/- 0.14 for g band data and 0.85 +/- 0.17 for r band data. We obtained the following results: ------------------------------------------------------------------ JD(Start)| Exposure(sec) | Filter | Mag | lim_Mag | ------------------------------------------------------------------ 2458952.1903 | 550 | g | 18.301+/-0.034 | 20.92 2458952.3277 | 550 | g | 18.590+/-0.039 | 20.54 2458952.3601 | 550 | g | 18.761+/-0.040 | 20.52 2458952.3768 | 550 | g | 18.826+/-0.039 | 20.56 2458952.4216 | 550 | g | 18.984+/-0.041 | 20.65 2458952.1982 | 550 | r | 17.854+/-0.027 | 20.83 2458952.3356 | 550 | r | 17.998+/-0.036 | 20.32 2458952.3681 | 550 | r | 18.231+/-0.031 | 20.58 2458952.3847 | 550 | r | 18.314+/-0.039 | 20.65 2458952.4295 | 550 | r | 18.379+/-0.033 | 20.77 ------------------------------------------------------------------ The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).
GCN 27600 table
GRB_name GRB200412B
GCN_number 27600
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27600 SUBJECT: GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits DATE: 20/04/17 17:02:07 GMT FROM: Boris Sbarufatti at PSU B. Sbarufatti (PSU), N. P. M. Kuin (UCL-MSSL), P. A. Evans (U. Leicester), and J. D. Gropp (PSU) report on behalf of the Swift team: Swift XRT performed follow up observations on the afterglow candidate reported by Page et al. (GCN #27561). XRT data now comprise 6.1 ks of Photon Counting data covering times from T+20 ks to T+370 ks. The light curve is best fit by a power-law with decay index 1.6 +/- 0.3. We thus confirm that this is indeed the afterglow of GRB 200412B. The latest results can be viewed via: https://www.swift.ac.uk/xrt_curves/00020981/ In the initial Swift observation about 20ks after the trigger, the source was not in the UVOT field of view, which is smaller than that of the XRT. In the follow up observations around 360ks after the trigger we obtained the following 3-sigma upper limits to the source (Vega magnitudes, uncorrected for reddening): filter exposure UL (mag) v 374 >19.76 b 374 >20.74 u 374 >20.41 uvw1 749 >20.31 uvm2 1201 >20.48 uvw2 1499 >20.83 This circular is an official product of the Swift team.
GCN 27604 table
GRB_name GRB200412B
GCN_number 27604
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27604 SUBJECT: GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations DATE: 20/04/18 16:55:29 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), A.V. Shein (INASAN), I.A. Izvekova (ICAMER NASU), E. Klunko (ISTP), M. Eselevich (ISTP), R. Ya. Inasaridze (AbAO), V.R. Ayvazian (AbAO), G. V. Kapanadze (AbAO), I. Reva (FAPHI), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of GRB IKI FuN: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with Zeiss-2000 of Mt.Terskol observatory, Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory, AZT-33IK 1.5-m telescope of Sayan observatory (Mondy) and AS-32 (0.7m) telescope of Abastumani Observatory. We still detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555, 27556; see also e.g. Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570; Xin et al., GCN 27571). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter OT Err. UL Observatory (mid, days) 2020-04-13 23:10:27 1.59707 18*120 R 20.57 0.03 22.8 Terskol Z-2000 2020-04-15 14:55:11 3.25105 15*120 V 21.95 0.14 22.8 Mondy AZT-33IK 2020-04-16 17:04:23 4.33800 11*120 R n/d n/d 20.5 Mondy AZT-33IK 2020-04-16 22:30:40 4.57812 61*60 R n/d n/d 22.2 AbAO AS-32 2020-04-17 14:51:32 5.25754 28*120 R 23.22 0.28 23.4 Mondy AZT-33IK 2020-04-17 19:53:06 5.47912 91*60 R n/d n/d 22.3 TSHAO Z-1000 2020-04-17 20:12:07 5.48573 36*120 R 23.29 0.29 23.4 Terskol Z-2000 The photometry is based on nearby USNO-B1.0 stars. The light curve based on on above photometry and photometry published earlier (Belkin et al., GCN 27574; Belkin et al., GCN 27566; Belkin et al., GCN 27583) can be found at http://grb.rssi.ru/GRB200412B/GRB200412B_LC.png (For reference, we also posted the photometric results of the Tautenburg Observatory (Klose et al., GCN 27593; Stecklum et al., GCN 27582; Klose et al., GCN 27575; Stecklum et al., GCN 27567). The index of power law decay taken from our R-filter observations up to 2.3 days is -1.58+/-0.07 (see also Xin et al. GCN 27571; Klose et al., GCN 27575). Later we may assume a jet break previously suggested by Klose et al. (GCN 27575) and Stecklum et al. (GCN 27567).
GCN 27605 table
GRB_name GRB200412B
GCN_number 27605
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27605 SUBJECT: GRB 200412B: continued Terskol optical observations DATE: 20/04/19 13:50:32 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), A.V. Shein (INASAN), I.A. Izvekova (ICAMER NASU), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of GRB IKI FuN: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with Zeiss-2000 of Mt.Terskol observatory. We marginally detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555, 27556; see also e.g. Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570; Xin et al., GCN 27571). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter OT Err. UL Observatory (mid, days) 2020-04-18 19:52:22 6.47687 43*120 R 23.6 0.3 23.6 Terskol Z-2000 The photometry is based on nearby USNO-B1.0 stars. The update light curve can be found at http://grb.rssi.ru/GRB200412B/GRB200412B_LC.png
GCN 27610 table
GRB_name GRB200412B
GCN_number 27610
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27610 SUBJECT: GRB 200412B: continued Mondy and Terskol optical observations DATE: 20/04/20 19:47:32 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), A.V. Shein (INASAN), I.A. Izvekova (ICAMER NASU), E. Klunko (ISTP), M. Eselevich (ISTP), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of GRB IKI FuN: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with AZT-33IK 1.5-m telescope of Sayan observatory (Mondy) and Zeiss-2000 of Mt.Terskol observatory. We detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555, 27556; see also e.g. Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570; Xin et al., GCN 27571). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter OT Err. UL Observatory (mid, days) 2020-04-19 16:10:31 7.32142 41*120 R 23.50 0.30 23.6 Mondy AZT-33IK 2020-04-19 22:23:48 7.59245 48*120 R 23.55 0.28 23.7 Terskol Z-2000 The photometry is based on nearby USNO-B1.0 stars. The updated light curve can be found at http://grb.rssi.ru/GRB200412B/GRB200412B_LC.png
GCN 27653 table
GRB_name GRB200412B
GCN_number 27653
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 27653 SUBJECT: Gagarin-day GRB 200412B: observations with the 3.6m Devasthal Optical Telescope DATE: 20/04/26 11:12:48 GMT FROM: Shashi Bhushan Pandey at ARIES, INDIA Amit Kumar, S. B. Pandey, Amar Aryan, Brijesh Kumar and Kuntal Misra (ARIES Nainital), on behalf of a larger GRB collaboration. Fermi-GBM triggered GRB 200412B (GCNCs 27547, 27548i, 27558) prompt emissions and high energy observations were also carried out by Fermi-LAT (GCNC 27557) and other space-based facilities like Konus-Wind (GCNC 27581), ASTROSAT (GCNC 27563), CALET (GCNC 27572) and HXMT (GCNC 27567). Categorised as a long-duration GRB, Swift-XRT triggered and found a X-ray afterglow counterpart (GCNC 27561, 27600) decaying typical to those seen in case of other long duration bursts at the epoch of observations. Our joint spectral analysis of the combined Fermi GBM-LAT data yields E_peak ~ 250 +/- 18 keV and spectral slope \beta ~ -2.8 +/- 0.4 above 100 MeV, similar to those reported in GCNC 27558 and GCNC 27581. Once used with the empirical Amati relation, the estimated value of the E_peak and the observed fluence values (GCNC 27558, GCNC 27581) place a constrain of the redshift to be 0.3 < z < 1.5 for GRB 200412B. The optical counterpart of the Gagarin-day burst was discovered by MASTER group of telescopes (GCNC 27555, 27556) and follow-up observations were continued by several ground-based facilities (GCNCs 27564, 27566, 27567, 27567, 27570, 27571, 27574, 27575, 27576, 27583, 27593, 27598, 27604, 27605 and 27610). Late time follow-up observations of the optical counterpart were initiated using the 4Kx4K CCD Imager (Pandey et al. 2017, arXiv:1711.05422v1) mounted at the axial port of the 3.6m Devasthal Optical Telescope of ARIES Nainital starting on 15th April and continued till 25th April 2020. Multiple frames having exposure times of 360s each were taken in various broad-band filters including Ic, Rc and g-bands. A fading afterglow candidate was clearly seen in single as well as in stacked frames decayed around ~ 3 mag during our observing run. We report following preliminary brightness of the optical afterglow seen in our stacked frames calibrated against UNSOB1 and PanSTARRS nearby stars. Start time, 23 April 20.61 UT, 360*12, Rc, 24.62+/-0.12, seeing ~ 0.8 arcsec Start time, 24 April 19.71 UT, 360*10, g, 25.21+/-0.10, seeing ~ 0.9 arcsec Once clubbed along with published GCNC values in R-band, our late time observations indicate towards a power-law decay nature of the afterglow as seen in case of other well-monitored afterglows. The temporal decay index between one day to the epoch of our observations demand a power-law temporal flux-decay index of ~ 1.78+-0.15. This temporal decay is similar to those seen at XRT frequencies and might indicate towards possible early time jet-break, if any. It is also to be cautioned that possible underlying host galaxy contamination to our late time Rc-band stacked frames can not be ruled out. Detailed analysis of the data is ongoing. To decipher about late time nature of the temporal decay of the afterglow and to detect the host galaxy or possible underlying supernova, observations using bigger optical-NIR facilities are encouraged. This circular may be cited. 3.6m Devasthal Optical Telescope (DOT) is a recently commissioned facility in Northern Himalayan region of India (long:79 41 04E, lat:29 21 40N, alt:2540m) owned and operated by the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (https://www.aries.res.in). Authors of this GCN circular thankfully acknowledge consistent support from the staff members to run and maintain the 3.6m DOT and specially to Director ARIES to make these observations possible during the ongoing COVID19 triggered lock-down phase.