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"35260 results found.
- GRB 220831A: DECam detection of a possible optical counterpart
- Fermi GRB 220902A: Global MASTER-Net observations report
- GRB 220902A: Fermi GBM Final Real-time Localization
- GRB 220831A, VLT/HAWK-I near-infrared observations
- GRB 220831C: Fermi GBM Final Localization
- GRB 220831A: Fermi GBM observation
- GRB 220831A: Swift-XRT observations
- GRB 220831B: Fermi GBM Final Localization
- GRB 220831A: Swift ToO observations
- GRB 220831A: Swift/BAT-GUANO localization of a short burst
- Fermi GBM trigger 683571622/220830709 is not a GRB
- Konus-Wind detection of GRB 220826A
- GRB 220827A: Fermi GBM Final Real-time Localization
- GRB 220826A: Swift-BAT refined analysis
- GRB 220826A: Fermi GBM observation
- GRB 220826A: Swift-XRT refined Analysis
- GRB 220825A: Fermi GBM observation
- GRB 220826A: Lesedi optical afterglow detection
- GRB 220826A: Swift/UVOT Detection
- GRB 220826A: iTelescope optical afterglow observations
- Swift GRB 220826A: Global MASTER-Net observations report
- GRB 220826A: Enhanced Swift-XRT position
- GRB 220826A: Swift detection of a burst with an optical counterpart
- GRB 220825A: Swift/BAT-GUANO detection
- GRB 220825A: Fermi GBM Final Localization
- GRB 220823A: Fermi GBM detection
- GRB 220823A: Swift/BAT-GUANO detection of a short burst
- GRB 220821A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 220813A
- GRB 220813A: VLT optical observations and possible host galaxy
- GRB 220813A: Swift/UVOT Detection
- GRB 220810A: Further Swift-XRT observations
- GRB 220813A: Swift-XRT refined Analysis
- Swift GRB 220813A: Global MASTER-Net observations report
- GRB 220813A: Enhanced Swift-XRT position
- GRB 220813A: Swift detection of a burst with an optical counterpart
- GRB 220810A: Swift-XRT observations
- GRB 220719A: Detection by VZLUSAT-2
- GRB 220810A: Swift ToO observations
- GRB 220810A: MeerLICHT detection of two afterglow candidates
- Fermi GBM trigger 681998863/220812505 is not a GRB
- Fermi GBM trigger 681890304/220811249 is not a GRB
- Fermi GRB 220810A: Global MASTER-Net observations report
- GRB 220810A: Fermi GBM Final Real-time Localization
- GRB 220627A: MeerKAT radio observations
- GRB 220806A: Swift-BAT refined analysis
- Fermi GBM trigger 681719116/220809267 is not a GRB
- Fermi GBM trigger 681633544/220808277 is not a GRB
- Fermi GBM trigger 681547990 / 220807287 is not a GRB
- GRB 220806A: Swift detection of a burst
- GRB 220804A: Fermi GBM Final Localization
- GRB 220803A: AstroSat CZTI detection
- Konus-Wind detection of GRB 220730A (short)
- GRB 220730A: Swift-BAT refined analysis
- GRB 220730A: Fermi GBM detection
- GRB 220730A: Swift-XRT afterglow detection
- GRB 220730A: Swift/UVOT Upper Limits
- GRB 220730A: Swift-XRT observations
- GRB 220729A: AstroSat CZTI detection
- Swift GRB 220730A: Global MASTER-Net observations report
- GRB 220730A: Swift detection of a short hard burst
- Fermi GRB 220728A: Global MASTER-Net observations report
- GRB 220728A: Fermi GBM Final Real-time Localization
- GRB 220726A: Fermi GBM Final Real-time Localization
- Fermi GRB 220724A: Global MASTER-Net observations report
- GRB 220724A: Fermi GBM Final Real-time Localization
- GRB 220715B: VIRT Optical Upper Limit
- Fermi GRB 220721A: Global MASTER-Net observations report
- GRB 220721A: Fermi GBM Final Real-time Localization
- Retraction: Fermi GBM trigger 679932336.585264/220719587 is not a GRB
- GRB 220715A: CALET Gamma-Ray Burst Monitor detection
- GRB 220711B: CALET Gamma-Ray Burst Monitor detection
- GRB 220719A: Fermi GBM Final Real-time Localization
- GRB 220715B: Swift-BAT refined analysis
- GRB220714B: UVOT detections
- GRB 220715B: Fermi GBM detection
- GRB 220715B: Swift-XRT refined Analysis
- GRB 220715B: Swift/UVOT Upper Limits
- GRB 220715B: Enhanced Swift-XRT position
- GRB 220715B: BOOTES-network optical upper limits
- Swift GRB 220715B: Global MASTER-Net observations report
- GRB 220715B: Prompt enhanced Swift-XRT position
- GRB 220715B: Swift detection of a burst
- GRB 220715B: Fermi GBM Final Real-time Localization
- GRB 220714B: Swift-BAT refined analysis
- GRB 220714B: Fermi GBM observation
- GRB 220715A: AGILE/MCAL detection
- GRB 220714B: LCO Optical Observations
- GRB 220715A: Fermi GBM Final Real-time Localization
- GRB 220714B: Swift-XRT refined Analysis
- Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
- GRB 220714B: UVOT afterglow discovery
- GRB 220714B: Enhanced Swift-XRT position
- GRB 220713A: Fermi GBM Final Localization
- GRB 220714B: Swift detection of a burst
- GRB 220714B: Fermi GBM Final Real-time Localization
- GRB 220714A: Possible Swift detection of a burst
- GRB 220710A: Swift/UVOT Upper Limits
- GRB 220711C: Fermi GBM Observation
- Retraction of GRB 220711B: 10.4 m GTC(+EMIR) observations (GCN 32387)