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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"27395 results found.
- GRB 220714B: Fermi GBM observation
- GRB 220714B: LCO Optical Observations
- GRB 220714B: Swift-XRT refined Analysis
- GRB 220714B: UVOT afterglow discovery
- GRB 220714B: Enhanced Swift-XRT position
- GRB 220714B: Swift detection of a burst
- GRB 220710A: Swift/UVOT Upper Limits
- GRB 220711C: Fermi GBM Observation
- GRB 220711B: 10.4 m GTC(+EMIR) observations
- GRB 220711B: 10.4 m GTC(+EMIR) observations
- GRB 220711C: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220711B, GROND observations
- GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
- GRB 220711B: GIT optical upper limits
- Fermi trigger No 679248723: Global MASTER-Net observations report
- Fermi GRB 220711B: Global MASTER-Net observations report
- GRB 220712B: NOT optical afterglow confirmation
- GRB 220710A: Swift/BAT-GUANO arcminute localization
- GRB 220711B: Swift-BAT refined analysis
- IPN triangulation of GRB 220711C (short)
- GRB 220711B: Swift-XRT refined Analysis
- GRB 220711B: Swift/UVOT Upper Limits
- GRB 220711B: Enhanced Swift-XRT position
- GRB 220711B: Fermi GBM Detection
- GRB 220711B: NOT optical observations
- GRB 220711B: LCO Optical Upper Limits
- GRB 220711B: Swift detection of a burst
- GRB 220707A: AstroSat CZTI detection
- GRB 220708B: GIT optical upper limits
- GRB 220708A: Swift-BAT refined analysis
- GRB 220708B: T193-OHP optical upper limit
- Konus-Wind detection of GRB 220708B
- GRB 220708B: Nanshan/NEXT optical upper limits
- GRB 220708A: Swift/UVOT Upper Limits
- GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
- GRB 220708A: Swift-XRT refined Analysis
- GRB 220706A: Swift/UVOT Upper Limits
- GRB 220708B: Swift-XRT afterglow detection
- GRB 220706A: Swift-BAT refined analysis
- GRB 220708A: Enhanced Swift-XRT position
- GRB 220708B: Swift/BAT-GUANO arcminute localization
- GRB 220708A: Swift-XRT observations
- GRB 220706A: LCO Optical Upper Limits
- GRB 220706A: Swift-XRT refined Analysis
- GRB 220706A, GROND observations
- GRB 220706A: Optical observations from NOT
- GRB 220702B: AstroSat CZTI detection
- GRB 220706A: Nanshan/NEXT optical upper limits
- MAXI GRB220706.73: Global MASTER-Net observations report
- GRB 220706A: Enhanced Swift-XRT position
- GRB 220706A: Zadko observatory - Gingin optical observations
- GRB 220706A: Swift detection of a burst
- GRB 220701A: Swift-BAT refined analysis
- GRB220408A: VIRT Optical Upper Limit
- GRB220412A: VIRT Optical Upper Limit
- GRB220701A: VIRT Optical Upper Limit
- GRB 220701A: MITSuME Akeno optical upper limits
- Alert from the HAWC Burst Monitor HAWC-220702A
- GRB 220701A: COATLI Optical Upper Limit
- GRB 220701A: AbAO optical upper limit
- GRB 220701A: Keck/LRIS Optical Upper Limit
- GRB 220701A: Swift-XRT refined Analysis
- GRB 220701A: LCO Optical Upper Limits
- IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220701A: Swift/UVOT Upper Limits
- GRB 220701A: Lowell Discovery Telescope Optical Observations
- GRB 220701A: Enhanced Swift-XRT position
- GRB 220701A: Swift detection of a burst
- Fermi-LAT Gamma-ray Observations of IceCube-220629A
- GRB 220627A, GROND observations
- GRB 220624A: AGILE/GRID refined analysis
- GRB 220627A: Swift/UVOT Upper Limits
- Fermi-LAT Gamma-ray Observations of IceCube-220627A
- IceCube-220629A: No significant detection in HAWC
- IceCube-220627A: No significant detection in HAWC
- GRB 220627A: Swift-XRT afterglow detection
- Konus-Wind detection of GRB 220627A
- Trigger 1113743: Swift detection of MAXI J0655-013
- IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220627A: VLT MUSE redshift
- Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
- GRB 220627A: MeerLICHT candidate optical afterglow
- GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
- GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
- Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
- GRB 220627A: Fermi-LAT detection
- GRB 220627A: MeerLICHT detection of two afterglow candidates
- IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-220624A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-220624A: No significant detection in HAWC
- GRB 220623A: GIT optical upper limits.
- GRB 220623A: T193-OHP optical upper limit
- GRB 220624A: Fermi GBM Detection
- Fermi GRB 220623B: Global MASTER-Net observations report
- IPN triangulation of GRB 220624A
- GRB 220623A: Swift-BAT refined analysis
- GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220624A: AGILE/GRID analysis
- GRB 220623A: AbAO optical upper limit
- GRB 220623A: Swift-XRT refined Analysis