GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"- IPN triangulation of GRB 230511D (short)
- IPN triangulation of GRB 230512A
- GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
- GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
- GRB 230512A: Zwicky Transient Facility non-detection of GRB afterglow candidate
- GRB 230512A: Liverpool Telescope observations
- GRB 230512A: GIT non detection of afterglow candidate
- GRB 230512A: Kitab possible afterglow candidate
- GRB 230512A: GRBAlpha detection
- GRB 230510A: GRBAlpha detection
- GRB 230513A: Fermi GBM Final Real-time Localization
- Fermi trigger No 705565670: Global MASTER-Net observations report
- Fermi-LAT gamma-ray observations of IceCube-230511A
- GRB 230510A: OHP/T193 and OHP/T120 optical observations
- GRB 230512A: Swift-XRT observations
- IceCube-230511A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230512A: GIT optical follow-up ZTF candidates
- GRB 230512A: Fermi GBM detection
- GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
- GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
- GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
- GRB 230512A: Tiled Swift observations
- GRB 230512A: Fermi-LAT detection
- GRB 230512A: AstroSat CZTI detection
- GRB 230512A: Fermi GBM Final Localization
- GRB 230510A: GIT optical upper limits
- GRB 230510A: LCOGT Optical Upper Limit
- GRB 230511D: Fermi GBM Final Real-time Localization
- GRB 230510A: Swift/UVOT Observations
- IceCube-230511A: IceCube observation of a high-energy neutrino candidate
- GRB 230510B: AstroSat CZTI detection
- GRB 230511C: Fermi GBM Final Localization
- Fermi trigger No 705503315: Global MASTER-Net observations report
- GRB 230511B: Fermi GBM Final Real-time Localization
- Fermi trigger No 705496510: Global MASTER-Net observations report
- GRB 230511A: Fermi GBM Final Real-time Localization
- GRB 230510A: Fermi GBM detection
- Fermi trigger No 705446499: Global MASTER-Net observations report
- GRB 230510A: Gaoyazi/GOT optical upper limit
- GRB 230510B: CALET Gamma-Ray Burst Monitor detection
- GRB 230510A: CALET Gamma-Ray Burst Monitor detection
- GRB 230510A: Nanshan/NEXT optical afterglow detection
- GRB 230510B: MAXI/GSC detection
- GRB 230510B: Fermi GBM Final Real-time Localization
- GRB 230506B: Fermi GBM detection
- GRB 230510A: Swift-XRT refined Analysis
- GRB 230510A: Enhanced Swift-XRT position
- GRB 230506C: Fermi GBM detection
- Fermi trigger No 705413051: Global MASTER-Net observations report
- Fermi Gamma-ray Burst Monitor trigger 230510133/705381054 is not a GRB
- GRB 230510A: Swift detection of a burst
- GRB 230510A: Fermi GBM Final Real-time Localization
- GRB 230506B: Swift/UVOT further analysis
- GRB 230506C: T193-OHP MISTRAL tentative redshift
- GRB 230506C: SAO RAS optical observations
- GRB 230307A: JWST second-epoch observations
- IceCube-230506A: Upper limits from a search for additional neutrino events in IceCube
- Fermi-LAT gamma-ray observations of IceCube-230506A
- GRB 230506C: Swift-XRT refined Analysis
- GRB 230506C: Swift-BAT refined analysis
- GRB 230506B: Swift-BAT refined analysis
- GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
- GRB 230506B: LCOGT Optical Upper Limits
- GRB 230506C: Swift/UVOT Upper Limits
- GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 230506B: Swift-XRT refined Analysis
- GRB 230506C: Swift-XRT analysis
- GRB 230506C: Candidate afterglow observation by D50
- GRB 230506C: TSHAO possible afterglow candidate
- GRB 230506B: Swift/UVOT Detection
- IceCube-230506A: IceCube observation of a high-energy neutrino candidate
- GRB 230506C: Swift detection of a burst
- Swift GRB230506.71: Global MASTER-Net observations report
- GRB 230506B: Swift detection of a burst
- GRB 230506B: MASTER optical observations
- GRB 230506B: Swift detection of a burst
- GRB 230506A: Fermi GBM Final Real-time Localization
- GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
- Fermi trigger No 704837952: Global MASTER-Net observations report
- GRB 230430A: A short GRB from a neutron star merger
- GRB 230427A: Swift-BAT refined analysis
- GRB 230503A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 230430A
- IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
- IPN triangulation of GRB 230430A (short)
- GRB 230420A: AROMA-N Optical Upper Limit
- GRB 230430B: Fermi GBM Final Localization
- GRB 230430A: Fermi GBM observation
- GRB 230430A: AstroSat CZTI detection
- GRB 230430A: Fermi GBM Final Real-time Localization
- GRB 230427A: NOT optical upper limit
- GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
- GRB 230427A: Swift/UVOT Detection
- Duplicate of GCN 33369
- GRB 230427A: Gaoyazi/GOT optical upper limit
- GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
- GRB 230427A: Nanshan/HMT optical upper limit
- GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
- GRB 230427A: OSIRIS+/GTC observations