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"27224 results found.
- Swift GRB230916.18: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
- GRB 230915A: Swift/BAT-GUANO detection of a burst
- LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
- GRB 230911D: GRBAlpha detection
- Swift GRB230916.19: Global MASTER-Net observations report
- Swift GRB230916.18: Global MASTER-Net observations report
- Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
- Swift GRB230916.13: Global MASTER-Net observations report
- Swift GRB230916.12: Global MASTER-Net observations report
- Swift GRB230916.11: Global MASTER-Net observations report
- Swift Trigger 1192233 is not a GRB
- GRB 230911A: Swift-XRT afterglow detection
- GRB 230913A: CALET Gamma-Ray Burst Monitor detection
- Swift Trigger 1192088 is not an astrophysical event
- GRB 230913A: Glowbug gamma-ray detection
- IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
- Swift Trigger 1191994 is not an astrophysical event
- Swift GRB230913.70: Global MASTER-Net observations report
- GRB 230913A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
- Swift Trigger 1191904 is not a GRB
- Swift GRB230913.70: Global MASTER-Net observations report
- Swift Trigger 1191903 is not an astrophysical event
- GRB 230911A: Swift ToO observations
- GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 230913A: Fermi GBM Final Real-time Localization
- GRB 230908A: CALET Gamma-Ray Burst Monitor detection
- GRB 230911D: NuSTAR Detection of Prompt Emission
- GRB 230911B: AstroSat CZTI 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 230911B: GRBAlpha and VZLUSAT-2 joint detection
- GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 230911B: correction to the KW GCN 34659
- Konus-Wind detection of GRB 230811D
- GRB 230911C: Enhanced Swift-XRT position
- GRB 230911D: Fermi GBM Final Localization
- GRB 230911C: Swift detection of a burst
- GRB 230911B: Fermi GBM Final Real-time Localization
- 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