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"
913 results found.
- GRB 240107A: VZLUSAT-2 detection
- GRB 240114A: MAXI/GSC detection
- GRB 240107A: AstroSat CZTI detection
- GRB 240107A: MAXI/GSC detection
- IPN triangulation of GRB 231129C
- GRB 231129C: ASIM MXGS observation and localization
- Konus-Wind detection of GRB 231129C
- GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
- GRB 231129B: Swift-XRT observations
- GRB 231129C: AGILE detection
- GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
- GRB 231129C: MASTER OT detection
- GRB 231129C: Fermi-LAT detection
- GRB 231129C: GRBAlpha detection
- GRB 231129C: Glowbug gamma-ray detection
- GRB 231129C: GECAM-B detection of a bright burst
- GRB 231129C: AstroSat CZTI detection
- GRB 231129C: CALET Gamma-Ray Burst Monitor detection
- GRB 231129C: Fermi GBM Observation of a very bright GRB
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129C: MAXI/GSC detection
- GRB 231129B: Tiled Swift observations
- GRB 231129B: MAXI/GSC detection
- LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
- GRB 231117A: ATLAS non-detection of an optical counterpart
- LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
- LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
- LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
- LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
- Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
- LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- Konus-Wind detection of GRB 220623A
- LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
- LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
- GRB 230623A: Swift-XRT observations
- GRB 230623A: Tiled Swift observations
- MAXI GRB 230623A: MASTER optical observations
- GRB 230623A: Tiled Swift observations
- GRB 230623A: MAXI/GSC detection
- LIGO/Virgo S230603aa: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
- GRB 230520A: CALET Gamma-Ray Burst Monitor detection
- GRB 230520A: MAXI/GSC detection
- LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
- LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
- GRB 230510B: Fermi GBM detection
- GRB 230510B: AstroSat CZTI detection
- GRB 230510B: CALET Gamma-Ray Burst Monitor detection
- GRB 230510B: MAXI/GSC detection
- GRB 230420A: Swift detection of a burst
- MAXI GRB230408.82: Global MASTER-Net observations report
- GRB 230307A: soft X-ray detection with LEIA
- GRB 230307A: MAXI/GSC upper limit
- GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
- GRB 230220A: Correction to GCN 33352
- GRB 230220A: MAXI/GSC detection
- GRB 230204B: CALET Gamma-Ray Burst Monitor detection
- GRB 230204B: ATCA radio detection
- GRB 230204B: MASTER early OT detection
- GRB 230204B: Swift/UVOT Upper Limits
- GRB 230204B: Fermi GBM detection
- GRB 230204B: Swift-XRT afterglow detection
- GRB 230204B: 3.6m DOT optical observation
- GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
- GRB 230204B: Swift ToO observations
- GRB 230204B: Detection by GRBAlpha
- GRB 230204B: AGILE detection
- GRB 230204B: GIT discovery of the likely optical afterglow
- GRB 230204B: AstroSat CZTI detection
- GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230204B: MAXI/GSC detection
- IceCube Alert 230122.16: Global MASTER-Net observations report
- GRB 230111A: Fermi GBM Observation
- GRB 230111A: MAXI/GSC detection
- GRB 221119A: Fermi GBM detection
- GRB 221028B: MAXI/GSC detection
- Konus-Wind detection of GRB 221017A
- GRB 221021A: Fermi GBM observation
- GRB 221017A: CALET Gamma-Ray Burst Monitor detection
- GRB 221017A: Swift-XRT observations
- GRB 221017A: Swift ToO observations
- IPN triangulation of GRB 221017A (long)
- MAXI GRB221017.24: Global MASTER-Net observations report
- GRB 221017A: MAXI/GSC detection
- MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
- MAXI GRB 221006A: Redshifts of the possible host galaxies
- GRB 221006A: Swift-XRT afterglow detection
- Afterglow limits of GRB 221006A from OHP
- GRB 221009A: NICER follow-up observations
- GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
- GRB 221006A: Swift ToO observations
- GRB 221006A: CALET Gamma-Ray Burst Monitor detection
- Integral GRB221010.89: Global MASTER-Net observations report