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"19549 results found.
- LIGO/Virgo S191215w : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191215w: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191213g: GMOS-N spectroscopy shows ZTF19acykzsk/AT2019wqj is a SN II
- LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S191213g: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191213g: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191204r: correction to GRAWITA GCN 26390
- Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
- Possible HAWC-detected GRB 191210A: no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL transient candidates discovery.
- LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
- LIGO/Virgo S191205ah: MASTER OT 1.5m OSN imaging and 10.4m GTC spectroscopy
- LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
- IceCube-191204A: No significant detection in HAWC
- LIGO/Virgo S191205ah: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S191205ah: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191205ah: No counterpart candidates in Fermi-LAT 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 S191205ah: SAGUARO observations and identification of an optical candidate
- LIGO/Virgo S191204r: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191205ah: No counterpart candidates in HAWC observations
- LIGO/Virgo S191205ah : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191205ah: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191205ah: Identification of a GW compact binary merger candidate
- LIGO/Virgo S191204r: no counterpart candidates in the Swift/BAT observations
- IceCube-191204A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191204r : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191204r: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 191130A: Swift ToO observations
- GRB 191004A: correction to reported GROND upper limits
- LIGO/Virgo S191129u: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191129u: Swift/BAT in SAA
- LIGO/Virgo S191129u: No counterpart candidates in HAWC observations
- LIGO/Virgo S191129u : no neutrino counterpart candidate in ANTARES search
- GRB 191125B: MASTER-VWFC synchronous observation
- IceCube-191122A: No significant detection in HAWC
- GRB 191123A: Swift/UVOT further analysis
- GRB 191123A: Enhanced Swift-XRT position
- GRB 191123A: iTelescope optical upper limits
- GRB 191123A: Swift/UVOT detection
- GRB 191123A: Swift detection of a burst with an optical counterpart
- GRB 191122A: Swift/UVOT Upper Limits
- GRB 191122A: Enhanced Swift-XRT position
- GRB 191122A: Swift detection of a burst
- IceCube-191119A: No significant detection in HAWC
- IceCube-191119A: Upper limits from a search for additional neutrino events in IceCube
- Fermi-LAT Gamma-ray Observations of IceCube-191119A
- IceCube-191119A - No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Swift Trigger 937114 is not an astrophysical source
- LIGO/Virgo S191110af: Potential pulsar counterparts
- LIGO/Virgo S191110af: Swift XRT observations, no secure afterglow found
- LIGO/Virgo S191110af: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191110af: No neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191110af: Evryscope observation report, no counterpart candidates
- LIGO/Virgo S191110af: No counterpart candidates in INTEGRAL SPI-ACS, prompt observation
- LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191109d: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191109d: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
- GRB 191108A: Fermi GBM Final Real-time Localization
- GRB 191106A: Swift/UVOT Upper Limits
- LIGO/Virgo S191105e: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191105e: no counterpart candidates in the Swift/BAT observations
- GRB 191106A: NOT optical upper limit
- GRB 191106A: Swift-XRT refined Analysis
- LIGO/Virgo S191105e : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
- LIGO/Virgo S191105e: No counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
- GRB 191106A: Mondy optical upper limit
- GRB 191106A: Swift detection of a burst
- GRB191016A GROND observations
- GRB 191101A: Swift/UVOT Upper Limits
- SGR 1935+2154: Swift-BAT refined analysis
- GRB 191031D: Gemini optical upper limit
- GRB 191101A: iTelescope optical limit
- GRB 191101A: VIRT Optical Upper Limits
- GRB 191101A: Enhanced Swift-XRT position
- GRB 191101A: Swift detection of a burst
- GRB 191031D: MMT Binospec Optical Upper Limit
- GRB 191031A: Swift-BAT refined analysis
- GRB 191031D: Swift/UVOT Upper Limits
- GRB 191031C: Swift/UVOT Detection
- GRB 191031D: COATLI Optical Observations
- GRB 191031D: RATIR Optical and NIR Observations
- GRB 191031D: Enhanced Swift-XRT position
- GRB 191031C: Enhanced Swift-XRT position
- GRB 191031D: Swift detection of a short hard burst
- GRB 191031C: Swift detection of a burst
- GRB 191031A: COATLI Optical Observations
- Konus-Wind observation of GRB 191027A
- GRB 191029A: Swift/UVOT Upper Limits
- GRB 191029A: Enhanced Swift-XRT position
- GRB 191029A: BOOTES-4/MET optical limit
- GRB 191029A: iTelescope optical upper limits