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"3039 results found.
- Fermi trigger No 600227156: Global MASTER-Net observations report
- IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200105ae: Global MASTER-Net observations report
- IPN triangulation of GRB 200101A
- IceCube-191231A: No significant detection in HAWC
- LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
- GRB 191227A: MITSuME Akeno optical upper limits
- LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
- LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
- LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
- Fermi trigger No 598543714: Global MASTER-Net observations report
- Swift GRB191220.56: Global MASTER-Net observations report
- LIGO/Virgo S191216ap, Swift XRT observations: 16 X-ray sources in the HAWC error region search
- LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
- LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
- LIGO/Virgo S191216ap: Nanshan follow-up observations
- LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations
- LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
- IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S191213ai: Global MASTER-Net observations report
- LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
- GRB 191203A: Insight-HXMT/HE detection
- LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
- LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
- LIGO/Virgo S191205ah: Global MASTER-Net observations report
- IceCube Alert 191204.95: Global MASTER-Net observations report
- GRB 191203A: Fermi GBM Final Real-time Localization
- Fermi trigger No 596786686: Global MASTER-Net observations report
- Fermi trigger No 596690552: 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
- GRB 191122A: Swift-BAT refined analysis
- GRB 191122A: CHES Optical Observations
- LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
- GRB 191106A: Swift-XRT refined Analysis
- Fermi trigger No 594592184: Global MASTER-Net observations report
- Swift GRB191105.01: Global MASTER-Net observations report
- Swift GRB191105.01: Global MASTER-Net OT detection
- SGR 1935+2154: Swift-BAT refined analysis
- Fermi trigger No 594563923: Global MASTER-Net observations report
- GRB 191031A: Fermi GBM detection
- IPN triangulation of GRB 191027A
- Fermi trigger No 593176520: Global MASTER-Net observations report
- Swift GRB191016.17: Global MASTER-Net observations report
- Fermi trigger No 592818648: Global MASTER-Net observations report
- ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence
- Fermi trigger No 592211224: Global MASTER-Net observations report
- Konus-Wind observation of GRB 191004B
- Konus-Wind observation of GRB 191004A
- LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
- Swift GRB191004.9: Global MASTER-Net OT detection
- LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
- Fermi trigger No 591604915: Global MASTER-Net observations report
- Konus-Wind observation of GRB 190928A
- LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Baksan Neutrino Observatory Alert 190920.65: Global MASTER-Net observations report
- Integral GRB190919.99: 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
- LIGO/Virgo S190915ak: No transient candidates in CALET observations
- Fermi trigger No 590335819: Global MASTER-Net observations report
- LIGO/Virgo S190915ak: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190915ak: Coverage and upper limits from MAXI/GSC observations
- GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
- LIGO/Virgo S190915ak : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190915ak: Upper Limits from AGILE-GRID observations
- LIGO/Virgo S190915ak: No counterpart candidate in AGILE-MCAL observations
- LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190915ak: Identification of a GW compact binary merger candidate
- GRB 190915A: BALROG localization (Fermi Trigger 590219102 / GRB 190915240)
- GRB 190915A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190814bv: No counterpart candidate after completion of GRAWITA VST-ESO PARANAL transient survey.
- LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
- LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190901ap: Gaia Photometric Alerts transient candidates
- LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
- GRB 190829A: GTC confirmation of an associated Type Ic-BL Supernova
- Fermi trigger No 589419513 Global MASTER-Net observations report
- LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
- LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
- LIGO/Virgo S190901ap : GRAWITA photometric observation of candidate ZTFabvizsw and GCN 25618 revision
- LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
- LIGO/Virgo S190901ap: Upper limits from Insight-HXMT/HE observations
- Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
- LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
- GRB 190829A: NOEMA detection of the mm afterglow
- GRB 190831A: Fermi GBM Final Real-time Localization
- GRB 190829A, Swift-BAT refined analysis