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"- Retraction of the Fermi/LAT high-energy counterpart for GRB 140330A
- GRB 140331A: Swift/UVOT Upper Limits
- GRB 140302A: TAROT La Silla observatory optical observations
- GRB 140323A: Zadko observatory - Gingin optical observations
- GRB 140330A: intense and persistent gamma-ray emission detected by AGILE
- GRB 140331A: Zadko observatory - Gingin optical observations
- Konus-Wind observation of GRB 140330A
- GRB 140129B: AAO optical upper limit
- GRB 140129A: Mondy optical observations
- GRB 140331A: MITSuME Okayama upper limits
- GRB 140331A: Enhanced Swift-XRT position
- IPN triangulation of GRB 130330A
- GRB 140331A: RATIR Optical and NIR Observations
- GRB 140331A: Swift detection of a burst
- GRB 140330A: Fermi-LAT Detection
- GRB 140329A: Fermi-LAT detection
- Konus-Wind observation of GRB 140329A
- IPN Triangulation of GRB 140329A
- MAXI ID=745548350 is UV Ceti
- GRB 140320D: MASTER optical observations
- GRB 140329A: Fermi GBM observation of a bright burst
- Swift trigger 593744: detection of a flare from UV Cet
- GRB 140320D: Suzaku WAM observation of the prompt emission
- GRB 140323A : Suzaku WAM observation of the prompt emission
- Fermi Gamma-ray Burst Monitor trigger 417486540 / 140326020 is not a GRB
- GRB 140226A/iPTF14yb: Mondy optical observations
- GRB 140320C: Mondy optical observations and afterglow confirmation
- Konus-Wind observation of GRB 140323A
- GRB 140323A: Fermi-LAT detection
- GRB 140323A: Swift-XRT refined Analysis
- GRB 140323A: Fermi GBM observation
- GRB 140323A: BOOTES-3 optical upper limit.
- GRB 140323A: Swift/UVOT Upper Limits
- GRB 140323A: Swift-BAT refined analysis
- GRB 140323A: Enhanced Swift-XRT position
- GRB 140323A: Swift detection of a burst
- GRB 140320A: RATIR Optical and NIR Observations
- Konus-Wind observation of GRB 140320D
- GRB 140320B: P60 detection of a very red afterglow
- IPN Triangulation of very intense GRB 140320D
- GRB 140320C: Mini-GWAC prompt observation
- GRB 140320C: Swift/UVOT Upper Limits
- GRB 140320A: Swift-BAT refined analysis
- GRB 140320B: Swift/UVOT Upper Limits
- GRB 140320A: Swift/UVOT Upper Limits
- GRB 140320C: Swift-XRT observations
- GRB 140320A: Confirmation of a fading X-ray afterglow
- GRB 140320C: Swift-XRT detection of the X-ray afterglow
- GRB 140320A: Fermi GBM detection
- GRB 140320B: Swift-XRT detection of the afterglow
- GRB 140320C: Mondy optical observations
- GRB 140320A: Enhanced Swift-XRT position
- GRB 140320A: Swift-XRT detection of an afterglow candidate
- GRB 140320C: MASTER optical observations
- GRB 140320C: FTN optical observations
- GRB 140320C: A long GRB detected by INTEGRAL
- GRB 140320B: Xinglong TNT upper limit
- GRB 140320B: ISON-NM optical observations
- GRB 140320B: A long GRB detected by INTEGRAL
- GRB 140320B: FTN optical afterglow candidate
- Swift Trigger 592558 is not an astrophysical source
- GRB 140320A: Fermi GBM observations suggest a short GRB
- GRB 140320A: Swift detection of a burst
- GRB 140318A: Continued RATIR Optical and NIR Observations
- GRB 140318A: Mondy optical limit
- GRB 140318A: Swift/UVOT Upper Limits
- GRB 140318A: Swift-BAT refined analysis
- GRB 140311B: Mondy optical limit
- GRB 140311A: Mondy optical limits
- GRB 140318A: Swift-XRT refined Analysis
- GRB 140318A: Liverpool Telescope optical observations
- GRB 140318A: Enhanced Swift-XRT position
- GRB 140318A: RATIR Optical and NIR Detections
- GRB140318A: Discovery Channel Telescope Optical Detection
- GRB 140318A: WHT spectroscopy
- GRB 140318A: NOT detection of the afterglow
- GRB 140318A: Swift detection of a burst
- GRB 140311A: VLA Detection
- GRB140308A: Suzaku WAM observation of the prompt emission
- GRB 140311C: MASTER optical observations
- GRB 140311C: Swift-XRT and UVOT observations
- GRB 140311C: MASTER before, during and after trigger optical observations
- GRB 140311A: further NOT observations
- GRB 140311B: Swift-BAT refined analysis
- GRB 140311A: RATIR Optical and NIR Detection
- GRB 140311C: Fermi GBM Detection
- GRB 140311A: Montarrenti Observatory optical upper limit
- GRB 140311B: Fermi GBM Detection
- GRB 140311A: Kottamia I-band observation
- GRB 140311A: Swift/UVOT Upper Limits
- GRB 140311B: Swift/UVOT Upper Limits
- Fermi416242156: possible iPTF counterpart
- GRB 140311B: RATIR Optical and NIR Observations
- GRB 140311A: Bassano Bresciano Observatory optical upper limit
- GRB 140311A: Swift-XRT refined Analysis
- GRO J1744-28: Fermi GBM observation
- GRB 140311A: Gemini-North redshift
- GRB 140302A: GROND confirmation of the afterglow
- GRB 140311A: NOT redshift confirmation
- GRB 140311B: Swift-XRT refined Analysis