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"19600 results found.
- Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- Swift GRB230825.75: Global MASTER-Net observations report
- Swift Trigger 1187199 is not an astrophysical event
- Fermi Gamma-ray Burst Monitor trigger 714618399/230825046 is not a GRB
- NICER detection of Swift J1727.8-1613 (GRB 230824A)
- Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
- GRB 230824A: AKO Optical Afterglow Candidate
- Trigger 1186982: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
- GRB 230824A: Swift detection of a burst
- Swift GRB230824.58: Global MASTER-Net observations report
- Swift GRB230824.10: Global MASTER-Net observations report
- Swift Trigger 1186908 is not a GRB
- GRB 230822A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
- GRB 230822A: Swift/BAT-GUANO detection of a burst
- GRID detection of GRB 230818A
- GRB 230815A: ATCA detection of radio counterpart
- Swift GRB230821.64: Global MASTER-Net observations report
- GRB 230818A: Swift-BAT refined analysis
- Swift Trigger 1186391 is not a GRB
- Swift Trigger 1186390 is not a GRB
- Konus-Wind detection of GRB 230818A
- Swift Trigger 1186386 is not a GRB
- Swift triggers 1186294-1186304 are not astrophysical transients
- Swift GRB230820.81: Global MASTER-Net observations report
- Swift GRB230820.80: Global MASTER-Net observations report
- Swift GRB230820.82: Global MASTER-Net observations report
- Swift Triggers 1186280 and 1186291 are not GRBs
- GRB 230818A: Fermi GBM Observation
- GRB 230818A: SAO RAS 6-m telescope spectroscopy
- GRB 230818A: AKO Upper Limit
- GRB 230818A: AstroSat CZTI detection
- GRB 230818A: Leavitt Observatory upper limit
- GRB 230818A: Swift-XRT refined Analysis
- GRB 230818A: Bassano Bresciano Observatory optical observations
- GRB 230818A: KGO RC-25 optical observations
- GRB 230818A: Swift/UVOT Detection
- GRB 230818A: NOT photometry and spectroscopy
- GRB 230818A: Enhanced Swift-XRT position
- GRB 230818A: Swift detection of a burst
- Swift GRB230818.98: Global MASTER-Net observations report
- Swift GRB230818.98: Global MASTER-Net OT detection
- GRB 230816A: Swift-BAT refined analysis
- GRB 230816A: SVOM/C-GFT optical detection
- GRB 230816A: Swift-XRT refined Analysis
- GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
- GRB 230816A: Enhanced Swift-XRT position
- GRB230816A: Possible host and GIT detection of optical counterpart
- Swift GRB230816.80: Global MASTER-Net observations report
- IPN triangulation of GRB 230815B
- GRB 230816A: Nanshan/HMT optical afterglow detection
- GRB 230815A: SOAR/Goodman follow-up imaging
- Swift GRB230816.67: Global MASTER-Net observations report
- GRB 230816A: Swift detection of a burst
- GRB 230815A: Swift-BAT refined analysis
- GRB230815A: Swift/UVOT upper limits
- GRB 230812B: GAD Observatory optical observations (upper limit)
- GRB 230815A: Swift-XRT refined Analysis
- GRB 230812B: iTelescope optical upper limit
- GRB230815A: BOOTES-6/DPRT optical upper limit
- GRB 230815A: Fermi GBM detection
- Swift GRB 230815A: Global MASTER-Net observations report
- GRB 230815A: Enhanced Swift-XRT position
- GRB 230815A: Swift detection of a burst
- GRB 230812B: Upper limits from a neutrino search with IceCube
- GRB 230812B: GIT optical follow-up
- GRB 230812B: Faulkes Telescope North optical afterglow follow-up
- GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
- GRB 230812B: OASDG optical observations
- GRB 230812B: Detected Optical Afterglow Candidate
- GRB230812B: AGILE/MCAL detection
- GRB 230812B: Swift-XRT afterglow detection
- GRB 230812: Swift/UVOT Detection
- GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
- GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
- Fermi GRB 230812B: MASTER optical counterpart
- GRB 230812B: KAIT Optical Afterglow Candidate
- GRB 230812B: Improved Swift/XRT localization
- GRB 230812B: Preliminary Swift/XRT localization
- GRB 230812B: Tiled Swift observations
- GRB 230808A: Fermi GBM Detection
- GRB 230805B: Swift-BAT refined analysis
- GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
- GRB 230805B: AstroSat CZTI detection
- GRB 230808A: Swift/BAT-GUANO detection of a burst
- GRB 230805B : MITSuME Akeno optical upper limits
- LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
- GRB 230805B: Fermi GBM observation
- GRB 230805B: Enhanced Swift-XRT position
- GRB 230805B: Swift/UVOT Upper Limits
- GRB 230805B: Bassano Bresciano observatory upper limit
- GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
- GRB 230805B: Swift-XRT refined Analysis
- Swift GRB 230805B: Global MASTER-Net observations report
- GRB 230805B: Swift detection of a burst
- GRB 230802A: Fermi GBM observation
- GRB 230802A: Swift-BAT refined analysis
- GRB 230802A: Swift/UVOT Upper Limits