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"- IPN Triangulation of GRB 160822A (short/hard)
- Konus-Wind observation of GRB 160820A
- IPN Triangulation of GRB 160820A (short/hard)
- Possible radio detection of GRB160703A with the GMRT
- Possible radio detection of GRB160623A with the GMRT
- GRB 160821B: GTC follow-up observation
- GRB 160821B: WHT afterglow confirmation and redshift of candidate host
- GRB 160822672: Fermi GBM detection
- GRB 160821B: Swift-BAT refined analysis
- GRB 160821B: Fermi GBM Detection
- Konus-Wind observation of GRB 160821A
- GRB 160821B: Swift-XRT refined Analysis
- GRB 160821A: Swift-BAT refined analysis
- GRB 160821B: Swift/UVOT Upper Limits
- Short GRB 160821B: MASTER early optical observations
- GRB 160821B: Enhanced Swift-XRT position
- GRB 160821A: Fermi-LAT refined analysis
- GRB 160821A: Fermi GBM Detection
- GRB 160821B: NOT optical afterglow candidate
- GRB 160821B: Swift detection of a short burst
- GRB 160821A: TAROT Calern observatory optical detection
- GRB 160821A: Fermi-LAT detection of a bright burst
- GRB 160821A: Swift detection of a bright burst
- GRB 160816A: TSHAO optical observations
- INTEGRAL/SPI-ACS observation of IceCube HESE 128340 58537957
- BAT detection and localization of GRB 160819A
- GRB 160819A: Fermi GBM detection
- GRB 160816A: ISON/UAFO optical observations
- GRB 160816A: Further RATIR Optical and NIR Observations
- GRB 160815A: CALET Gamma-Ray Burst Monitor detection
- IBAS Alert 7534: Not a real GRB
- GRB 160816A: MASTER OT early detection on coaded images
- GRB 160816A: RATIR Optical and NIR Afterglow Confirmation
- GRB 160816A: confirmed fading with the LT
- GRB 160816A iTelescope observation
- Fermi GBM Observations of IceCube-160806A
- GRB 160814A: CALET Gamma-Ray Burst Monitor detection
- GRB 160816A: Swift/UVOT Detection
- GRB 160816A: IPN annulus
- GRB 160804A: 15 GHz detections and upper limit from AMI
- GRB 160801A: 15 GHz upper limits from AMI
- GRB 160714A: 15 GHz upper limits from AMI
- Konus-Wind observation of GRB 160816A
- GRB 160816A: RATIR Optical and NIR Observations
- GRB 160816A: LCOGT-FTN optical candidate
- GRB 160815A: GWAC-F60A upper limit
- GRB 160816A: Swift-XRT afterglow detection
- GRB 160816A: MASTER inspection
- GRB 160816730A: Fermi GBM detection/observation
- GRB 160816A: Swift ToO observations
- GRB 160816A: Fermi-LAT detection
- GRB 160815A: Swift/UVOT Detection
- Konus-Wind observation of GRB 160814A
- GRB 160815A: Swift-BAT refined analysis
- GRB 160815A: Swift-XRT refined Analysis
- GRB 160815A: Fermi GBM detection/observation
- GRB 160815A: Enhanced Swift-XRT position
- GRB 160815A: Swift/UVOT Afterglow Detection
- GRB 160815A: Swift detection of a burst
- GRB 160814A: MAXI/GSC detection
- GRB 160804B: CALET Gamma-Ray Burst Monitor detection
- IceCube 160806A: Lomonosov BDRG gamma ray prompt observations
- Fermi GBM trigger 160812507/492696620 is not a GRB
- INTEGRAL/SPI-ACS and IBIS_VETO search for prompt gamma-ray counterpart of IceCube-160806A
- Fermi GBM trigger 160810523/492525192 is not a GRB
- IceCube 160806A EHE Neutrino Candidate Event
- GRB 160806A: Fermi GBM observation
- Konus-Wind observation of GRB 160806A
- IPN Triangulation of GRB 160806A
- Swift Trigger 707517 is not an astrophysical event
- GRB160802A - Astrosat CZTI detection
- Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
- Swift Trigger 707517 is probably not a GRB
- GRB 160804A: RATIR Optical and NIR Observations
- GRB 160802A: CALET Gamma-Ray Burst Monitor detection
- IceCube-160731A: Konus-Wind limits
- GRB 160804A: TSHAO optical observations
- GRB 160804A: ISON/UAFO optical observations
- GRB 160804A: GROND observations
- GRB 160804A: VLT/X-shooter redshift
- Search for counterpart to IceCube-160731A with ANTARES
- GRB 160804A: SAO RAS optical observations
- GRB 160804A: TNG optical observations, afterglow fading and candidate host galaxy
- GRB 160804A: Fermi GBM observation
- GRB160804A: MASTER-SAAO observation
- Konus-Wind observation of GRB 160802A
- IPN Triangulation of GRB 160802A
- GRB 160804A: Swift-BAT refined analysis
- GRB 160804A: Swift/UVOT Detection
- GRB 160804A: Swift-XRT refined Analysis
- GRB 160804A: Enhanced Swift-XRT position
- GRB 160804A: Swift detection of a burst
- IceCube-160731A: iPTF P48 Observations
- GRB 160802A: Lomonosov BDRG gamma ray detection
- GBM Observations of IceCube 160731
- GRB 160801A: TSHAO optical observations
- GRB 160801A: Swift/UVOT Upper Limits
- GRB 160801A: SAO RAS optical observations
- GRB 160802A: Fermi GBM detection
- GRB 160801A: NOT upper limits