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"27777 results found.
- GRB 230911A: Fermi GBM Final Real-time Localization
- GRB 230906A: BlackGEM upper limits
- GRB 230903A: TESS observations of optical emission
- GRB 230906A: AstroSat CZTI detection
- GRB 230910A: Fermi GBM Final Real-time Localization
- GRB 230908A: GRBAlpha detection
- GRB 230908A: AstroSat CZTI detection
- Glowbug gamma-ray detection GRB 230905B
- GRB 230906A: Swift/UVOT Upper Limits
- GRID detection of GRB 230827A
- GRB 230906A: Swift-XRT observations
- Konus-Wind detection of GRB 230906A (short)
- IPN triangulation of GRB 230906A (short)
- GRB 230906A: Swift ToO observations
- GRB 230905B: AstroSat CZTI detection
- Swift Attitude Control Affecting Some UVOT Images
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- GRB 230906A: Fermi GBM Final Localizationn
- GRB 230905B: GECAM-C detection of a long burst
- GRB 230905A: Fermi GBM Final Real-time Localization
- 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 230904C: Fermi GBM Final Localization
- GRB 230903A: Fermi GBM detection
- GRB 230904A: Fermi GBM Final Real-time Localization
- GRB 230903A: LCOGT Optical Upper Limits
- GRB 230903A: Swift detection of a burst
- Swift GRB230903.72: Global MASTER-Net observations report
- GRB 230903A: Fermi GBM Final Real-time Localization
- GRB 230827B: Glowbug gamma-ray detection
- GRB 230827A: Glowbug gamma-ray detection
- GRB 230826A: Glowbug gamma-ray detection
- GRB 230827B: Swift-XRT afterglow detection
- LIGO/Virgo/KAGRA S230830b: Retraction of GW compact binary merger candidate
- GRB 230812B: Spectroscopic detection of the associated SN 2023pel.
- GRB 230827B: Swift ToO observations
- GRB 230827A: Fermi GBM Observation
- GRB 230827B: CALET Gamma-Ray Burst Monitor detection
- GRB 230826A: Swift-BAT refined analysis
- GRB 230828A: AstroSat CZTI detection
- GRB 230828A: GRBAlpha detection
- 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
- GRB 230827B: VZLUSAT-2 detection
- GRB 230827A: GRBAlpha detection
- Subject: GRB230826A: Swift/UVOT upper limits
- Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
- GRB 230827A: Fermi GBM Final Real-time Localization
- AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
- 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
- GRB 230826A: Fermi GBM Final Real-time Localization
- 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
- GRB 230818B: CALET Gamma-Ray Burst Monitor detection
- 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
- GRB 230812B: radio detection with the VLA
- 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 230824B: AstroSat CZTI detection
- 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
- IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 230812B: AstroSat LAXPC detection
- GRB 230818B: VZLUSAT-2 detection
- GRB 230818B: AstroSat CZTI detection
- GRID detection of GRB 230818A
- GRB 230822A: Fermi GBM Final Real-time Localization
- GRB 230815A: ATCA detection of radio counterpart
- Swift GRB230821.64: Global MASTER-Net observations report
- GRB 230818A: Swift-BAT refined analysis