GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"3757 results found.
- LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
- GRB 191221B: Swift detection of a burst and a very bright optical candidate
- GRB 191221A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
- Konus-Wind observation of GRB 191218A
- LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
- LIGO/Virgo S191216ap: No transient candidates in CALET observations
- LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S191215w: No transient candidates in CALET observations
- IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191213g: No transient candidates in CALET observations
- LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
- LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
- LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
- LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
- LIGO/Virgo S191204r: No transient candidates in CALET observations
- IceCube Alert 191204.95: Global MASTER-Net observations report
- Fermi trigger No 597049044: Global MASTER-Net observations report
- LIGO/Virgo S191129u: No transient candidates in CALET observations
- Fermi trigger No 596808579: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
- Fermi trigger No 596387570: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
- LIGO/Virgo S191124be: Global MASTER-Net observations report
- IceCube-191122A: Global MASTER-Net observations report
- IceCube-191119A: No neutrino counterpart candidates in ANTARES search
- GRB 191117A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S191110af: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191105e: AstroSat CZTI upper limits
- LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
- GRB 191106A: MASTER optical observation
- Fermi trigger No 594592184: Global MASTER-Net observations report
- Fermi trigger No 594557071: Global MASTER-Net observations report
- GRB 191101B: Fermi GBM Final Real-time Localization
- GRB 191029A: Swift-XRT refined Analysis
- GRB 191028B: MASTER optical observation
- IPN triangulation of GRB 191025B (short)
- GRB 191028B: BALROG localization (Fermi Trigger 593964489 / GRB 191028589)
- GRB 191028B: Fermi GBM Final Real-time Localization
- Fermi GBM trigger 593931926/191028212 is not a GRB
- GRB 191028A: Fermi GBM Final Real-time Localization
- Fermi trigger No 593176520: Global MASTER-Net observations report
- Fermi trigger No 592211224: Global MASTER-Net observations report
- LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
- GRB 190928A: AstroSat CZTI detection
- Swift GRB191004.9: Global MASTER-Net OT detection
- LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
- LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
- LIGO/Virgo S190930t: HCT observations of ZTF19acbpsuf
- LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
- Fermi trigger No 591604915: Global MASTER-Net observations report
- LIGO/Virgo S190930t: Upper limits from CALET observations.
- LIGO/Virgo S190930s: Upper limits from CALET observations.
- GRB 190928A: CALET Gamma-Ray Burst Monitor detection
- Fermi trigger No 591391412: Global MASTER-Net observations report
- GRB 190928A: AGILE/MCAL detection of a burst
- Baksan Neutrino Observatory Alert 190928.37: Global MASTER-Net observations report
- Fermi trigger No 591321287: Global MASTER-Net observations report
- LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190923y: Upper limits from CALET observations.
- IceCube-190922B - HAWC follow-up
- LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
- LIGO/Virgo S190814bv: HST and ALMA observations of the host galaxy of ASKAP J005547-270433 / AT 2019osy
- Fermi trigger No 590621700: Global MASTER-Net observations report
- LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
- GRB 190828B: AstroSat CZTI detection
- LIGO/Virgo S190915ak: No transient candidates in CALET observations
- LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
- GRB 190828C: AstroSat CZTI detection
- LIGO/Virgo S190910d: MASTER previous detection of Gaia19eba/AT2019qam
- LIGO/Virgo S190910h: Upper limits from CALET observations.
- LIGO/Virgo S190910d: No transient candidates in CALET observations.
- LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
- LIGO/Virgo S190910d: AstroSat CZTI upper limits
- LIGO/Virgo S190910d Global MASTER-Net observations report
- LIGO/Virgo S190814bv: VLA/JAGWAR monitoring of the 50% containment region
- LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
- ZTF19abvizsw/AT2019pim, search for GRB in SPI-ACS/INTEGRAL data
- Fermi trigger No 589561732 Global MASTER-Net observations report
- GRB 190905A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
- LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
- LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
- LIGO/Virgo S190901ap: Upper limits from CALET observations.
- Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
- LIGO/Virgo S190901ap : SVOM/GWAC-F60A observation of transient ZTFabvizsw
- LIGO/Virgo S190828l: no counterpart candidate in the SVOM/GWAC observations
- LIGO/Virgo S190828j: no counterpart candidate in the SVOM/GWAC observations
- Fermi trigger No 589065714 Global MASTER-Net observations report
- LIGO/Virgo S190814bv : No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190828j: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
- LIGO/Virgo S190814bv: Upper limits from a two-week IceCube search for neutrinos from the direction of ASKAP J005547-270433
- Fermi trigger No 588801358 Global MASTER-Net observations report