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"- GRB 140824A: OSN optical limit
- GRB 140824A: Swift-XRT refined Analysis
- GRB 140824A: Swift-BAT refined analysis
- GRB 140824A: Enhanced Swift-XRT position
- GRB 140824A: MITSuME Ishigakijima upper limits
- GRB 140824A: Swift/UVOT Upper Limits
- GRB 140824A: Swift detection of a burst
- GRB 140817A: NOT optical observations
- Fermi GBM Trigger 140819576/ 430148973/ MASTER OT
- GRB 140817A: Khureltogot optical upper limit
- GRB 140818B: ISON-Kislovodsk and ISON-Burakan optical upper limit
- Fermi trigger 430148973: Swift-XRT observation
- GRB 140818A: GROND confirmation of afterglow candidate
- GRB 140808A/iPTF14eag: AMI 15 GHz detection
- GRB140819A: Deep GROND Upper Limits
- Fermi 430148973/MASTER candidate: LCO-Sutherland observations
- Fermi trigg_num 430148973: OSN I-band observations
- GRB 140818B, Swift-BAT refined analysis
- Fermi trigg_num 430148973: bright OT inside large error box!
- Konus-Wind observation of GRB 140818A
- GRB 140818B : Correction to GCN 16713
- GRB 140818B: Swift/UVOT Upper Limits
- GRB 140818B: Swift-XRT refined Analysis
- Radio upper limit on the GRB 140808A with the GMRT
- GRB 140818B: Fermi GBM detection
- GRB140818B : GROND afterglow candidate
- GRB 140818B: Enhanced Swift-XRT position
- GRB 140818B: OSN I-band afterglow candidate
- GRB 140817A: Swift/UVOT Afterglow Detection
- GRB 140818B: Swift detection of a burst
- GRB 140818A - Fermi GBM Detection
- Swift detection of SAX J1712.6-3739
- GRB 140818A: Swift-XRT and UVOT potential afterglow detection
- GRB 140818A: Correction to GCN 16702
- Konus-Wind observation of GRB 140817A
- GRB 140818A Tiled Swift observations
- GRB 140818A: MAXI/GSC detection
- GRB 140817A: Swift-XRT refined Analysis
- GRB 140817A: Fermi GBM Detection
- GRB 140817A: Swift-BAT refined analysis
- GRB 140817A draft circular on nearby galaxy
- GRB 140817A: Enhanced Swift-XRT position
- GRB 140817A: Swift-XRT position
- GRB 140817A: Swift detection of a burst
- GRB 140808A / PTFeag: VLA K-band observations
- GRB 140815A: GROND afterglow candidate
- Swift Trigger 609694 is probably not an astrophysical source
- GRB 140815A: Swift-XRT observations
- GRB 140815A: A long GRB detected by INTEGRAL
- GRB 140814A: Swift-XRT and UVOT observations
- GRB 140814A: MASTER optical follow-up inspection
- GRB 140814A: Swift-XRT and UVOT observations
- GRB 140814A: MAXI/GSC detection
- Swift Mission Operations Center Moving
- GRB 140808A / iPTF14eag optical follow-up at HCT
- IPN triangulation of GRB 140810A
- GRB 140808A: Confirmation of the Swift-XRT afterglow
- GRB140809A: Fermi GBM observation
- GRB 140810A: Fermi GBM observation
- Konus-Wind observation of GRB 140810A
- GRB140810A: Fermi-LAT detection
- Swift trigger 609139 is probably 4U 1850-03
- Swift observations of possible GRB 140809A candidate
- GRB 140809A : Virtual Telescope optical observations
- GRB 140809A (FERMI trigger 429246673): MASTER follow-up inspection
- Konus-Wind observation of GRB 140808A
- GRB 140808A: Swift/UVOT Upper Limits
- GRB 140808A: Redshift from the 10.4m GTC telescope
- GRB 140808A: Swift-XRT observations
- GRB 140808A: Fermi GBM detection
- GRB 140808A: optical afterglow candidate iPTF14eag
- GRB 140801A: AAO optical observations
- GRB 140801A: GROND Afterglow detection, unbroken decay
- GRB140801A: Swift/XRT further observations
- GRB 140730A: GROND Upper limits
- GRB 140801A: BTA confirmation of redshift
- GRB 140801A: Swift/UVOT Upper Limits
- GRB 140801A: Swift-XRT observations
- Konus-Wind observation of GRB 140801A
- GRB 140801A : Virtual Telescope optical observations
- GRB 140801A: Fermi GBM observation
- GRB 140801A: Redshift from the 10.4m GTC telescope
- GRB 140801A: NOT afterglow confirmation
- IPN triangulation of GRB 140801A (Fermi trigger 428612396)
- GRB 140801A: archival upper limits on the host galaxy
- GRB 140801A (FERMI trigger 428612396): MASTER brigth OT discovery
- GRB 140730A, Swift-BAT refined analysis
- GRB 140709B: TShAO optical upper limit
- GRB 140709A, the review of the sky area in plate archives
- Swift Trigger 607945: possible noise event in the direction of NGC2559
- Konus-Wind observation of GRB 140729A
- GRB 140730A: LCO-Sutherland observations
- GRB 140730A: Swift-XRT refined Analysis
- GRB 140730A: Swift/UVOT Upper Limits
- GRB 140730A: Enhanced Swift-XRT position
- GRB 140730A: Prompt enhanced Swift-XRT position
- GRB 140730A: Swift detection of a burst
- Radio upper limit on the GRB 140713A with the GMRT
- GRB 140729A: iPTF optical upper limit
- Swift Trigger 607506 is probably noise