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"21392 results found.
- GRB 230908A: CALET Gamma-Ray Burst Monitor detection
- GRB 230911C: Swift-XRT refined Analysis
- GRB 230911C: Swift-BAT refined analysis
- GRB230911C: BOOTES-6/DPRT optical upper limit
- GRB 230906A: Chandra detection of the X-ray afterglow
- Swift GRB 230911C: Global MASTER-Net observations report
- IPN triangulation of GRB 230911D (long)
- GRB 230911D: Fermi-LAT detection
- GRB230911C: LCOGT Optical Upper Limits
- GRB 230911C: Swift/UVOT Upper Limits
- GRB 230911C: GOTO optical upper limits
- GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 230911C: Enhanced Swift-XRT position
- GRB 230911C: Swift detection of a burst
- GRB 230906A: BlackGEM upper limits
- GRB 230903A: TESS observations of optical emission
- GRB 230906A: Swift/UVOT Upper Limits
- GRID detection of GRB 230827A
- GRB 230906A: Swift-XRT observations
- IPN triangulation of GRB 230906A (short)
- GRB 230906A: Swift ToO observations
- Swift Attitude Control Affecting Some UVOT Images
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- GRB 230903A: Swift-XRT refined Analysis
- GRB 230903A: Enhanced Swift-XRT position
- GRB 230903A: VLT/X-shooter optical observations
- GRB 230903A: Swift-BAT refined analysis
- GRB 230903A: Fermi GBM detection
- GRB 230903A: LCOGT Optical Upper Limits
- GRB 230903A: Swift detection of a burst
- Swift GRB230903.72: Global MASTER-Net observations report
- GRB 230827A: Glowbug gamma-ray detection
- GRB 230826A: Glowbug gamma-ray detection
- GRB 230827B: Swift-XRT afterglow detection
- GRB 230827B: Swift ToO observations
- GRB 230827A: Fermi GBM Observation
- GRB 230826A: Swift-BAT refined analysis
- Swift Trigger 1188089 is not a GRB
- GRB 230827A: VZLUSAT-2 detection
- GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 230826A: VZLUSAT-2 detection
- Subject: GRB230826A: Swift/UVOT upper limits
- Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
- Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
- GRB 230826A: GRBAlpha detection
- GRB 230826A: Fermi GBM Observation
- Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
- GRB 230826A: Enhanced Swift-XRT position
- GRB 230826A: Swift-XRT refined Analysis
- GRB 230826A: Mondy optical observations
- Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
- GRB 230826A: Swift detection of a burst
- Swift GRB230826.81: Global MASTER-Net observations report
- Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
- GRB 230824A: AKO Photometric Follow-up Observations
- LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
- Swift GRB230825.85: Global MASTER-Net observations report
- Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
- Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- 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