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"5831 results found.
- IceCube-191215A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S191205ah: Candidates from the Zwicky Transient Facility Public Survey
- Fermi trigger No 597955752: Global MASTER-Net observations report
- LIGO/Virgo S191213ai: Global MASTER-Net observations report
- Fermi trigger No 597909938: 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
- LIGO/Virgo S191205ah: MITSuME Observation of MASTER OT J123123.61-043847.2
- LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
- IceCube-191204A: No significant detection in HAWC
- 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
- Fermi GBM trigger 596808579/191130507 is not a GRB
- Fermi trigger No 596690552: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 191127.25: 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
- GRB 191122A: Swift detection of a burst
- IceCube-191119A: No significant detection in HAWC
- LIGO/Virgo S191109d: Not observable by CALET
- LIGO/Virgo S191110af: Identification of a GW unmodeled transient candidate
- LIGO/Virgo S191110af: Global MASTER-Net observations report
- LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191109d: AstroSat CZTI upper limits
- LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191109d: Global MASTER-Net observations report
- LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:
- LIGO/Virgo S191109d: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
- LIGO/Virgo S191109d: upper limits from AGILE/MCAL observations
- LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S191109d: Upper limits from IceCube neutrino searches
- LIGO/Virgo S191109d: Identification of a GW compact binary merger candidate
- ZTF19abvizsw: Upper limits from Konus-Wind observations
- 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
- Fermi GBM GRBs 191104 A, B, C and triggers 594534420/191104185 and 594563923/191104527 are not GRBs
- Fermi trigger No 594557071: Global MASTER-Net observations report
- Fermi trigger No 594551878: Global MASTER-Net observations report
- Fermi trigger No 594528816: Global MASTER-Net observations report
- GRB 191104B: Fermi GBM Final Real-time Localization
- GRB 191101A: Swift detection of a burst
- GRB 191031D: MITSuME Akeno optical upper limits
- GRB 191031C: Swift detection of a burst
- IPN triangulation of GRB 191025B (short)
- Fermi trigger No 593176520: Global MASTER-Net observations report
- GRB 191017A: Fermi GBM Final Localization
- GRB191016A: MITSuME Okayama optical observation
- 191017A: BALROG localization (Fermi Trigger 592997024 / GRB 191017391)
- Baksan Neutrino Observatory Alert 191016.51: Global MASTER-Net observations report
- GRB 191016A: Swift detection of a burst
- GRB 191009A: AstroSat CZTI detection
- GRB 191009A: BALROG localization (Fermi Trigger 592297741 / GRB 191009298)
- TESS Detection of the Optical Emission from the Possible Untriggered GRB Associated with ZTF19abvizsw
- Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
- LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
- GRB 190928A: AstroSat CZTI detection
- Swift GRB191004.9: Global MASTER-Net OT detection
- GRB 191004B: Swift detection of a burst with an optical counterpart
- FACT follow-up of IceCube-191001A
- IceCube-191001A: HAWC follow-up
- GRB 190919A: AstroSat CZTI detection
- LIGO/Virgo S190930t: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
- Fermi-LAT Gamma-ray Observations of IceCube-191001A
- LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
- IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IceCube-191001A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
- LIGO/Virgo S190930t and S190930s: MASTER OT J205529.78+220725.5/AT2019rpr further analysis
- GRB 191001B: MITSuME Akeno optical upper limits
- LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
- LIGO/Virgo S190930t and S190930s: MASTER PSN in unknown disk galaxy
- LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930t and S190930s: MASTER optical observation and optical transient
- LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930t: Upper limits from CALET observations.
- LIGO/Virgo S190930s: Upper limits from CALET observations.
- LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930s: no counterpart candidates in AGILE-GRID observations
- LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190930s : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190928A: Insight-HXMT/HE detection
- LIGO/Virgo S190930s: No counterpart candidates in AGILE-MCAL observations
- LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190930t: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190930t: Global MASTER-Net observations report
- LIGO/Virgo S190930t: Upper limits from IceCube neutrino searches
- LIGO/Virgo S190930s: Upper limits from IceCube neutrino searches
- LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190930s: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190930s: Global MASTER-Net observations report