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 170805A: AstroSat CZTI detection
- LIGO/Virgo G296853 TZAC TAROT observations
- LIGO/Virgo G297595: Konus-Wind observations
- LIGO/Virgo G297595: MASTER MASTER Bright PSN detection in error-box
- LIGO/Virgo G297595: INAF VST-ESO PARANAL observations
- LIGO/Virgo G297595: Subaru Hyper Suprime-Cam follow-up observations
- LIGO/Virgo G296853: Pierre Auger Observatory neutrino follow-up
- LIGO/Virgo G297595: REM optical/NIR observations
- LIGO/Virgo G297595 : MAXI/GSC observations
- LIGO/Virgo G297595: Updated localization from LIGO and Virgo data
- GRB 170810A: VLA Detection
- GRB 170813A: Fermi GBM observation
- Fermi GBM trigger 524493492/170815526 is not a GRB
- LIGO/Virgo G297595: Correction to luminosity distance stated in GCN 21474
- LIGO/Virgo G297595: Pan-STARRS coverage and transients over the first 5hrs
- LIGO/Virgo G297595: Insight-HXMT observations
- LIGO/Virgo G297595: Nearby Galaxies in the Localization Volume
- LIGO/Virgo G297595: Fermi GBM Observations
- LIGO/Virgo G297595: Swift/BAT data search
- LIGO/Virgo G297595: AGILE GRID observations
- LIGO/Virgo G297595 : Fermi-LAT search for high-energy gamma-ray counterpart
- GRB 170813A: Swift/UVOT Upper Limits
- LIGO/Virgo G297595 ANTARES search
- LIGO/Virgo G297595: INTEGRAL search for a prompt gamma-ray counterpart
- LIGO/Virgo G297595: AGILE MCAL observations
- LIGO/Virgo G297595: SPI-ACS/INTEGRAL data investigations
- LIGO/Virgo G297595: IceCube neutrino observations
- LIGO/Virgo G297595: Identification of a GW Binary Merger Candidate
- GRB 170813A: Swift-BAT refined analysis
- GRB 170813A: RATIR Optical and NIR Observations
- GRB 170810A: AbAO optical upper limit
- GRB 170813A: Swift-XRT refined Analysis
- GRB 170813A: Enhanced Swift-XRT position
- GRB 170813A: Swift detection of a burst
- LIGO/Virgo G296853: Liverpool Telescope classification of MASTER OT J013646.48-140323.5
- GRB 170728B: 15 GHz upper limits from AMI
- GRB 170728A: 15 GHz upper limits from AMI
- GRB 170714A: 15 GHz upper limits from AMI
- GRB 170711A: 15 GHz upper limits from AMI
- GRB 170710C: 15 GHz upper limits from AMI
- GRB 170710B: 15 GHz upper limits from AMI
- GRB 170626A: 15 GHz upper limits from AMI
- LIGO/Virgo G296853: BOOTES-1 and GTC optical observations
- GRB 170810A: Swift-BAT refined analysis
- LIGO/Virgo G296853: Insight-HXMT observations
- LIGO/Virgo G296853 : MAXI/GSC observations
- GRB 170810A: Swift-XRT refined Analysis
- GRB 170810A: Swift/UVOT Detection
- GRB 170810A: Fermi GBM observation
- GRB 170810A: Fermi-LAT detection
- GRB 170810A: Enhanced Swift-XRT position
- GRB 170810A: Swift detection of a burst with a bright optical counterpart
- GRB 170810A: MASTER-NET very bright OT detection
- LIGO/Virgo G296853: HAWC follow-up
- Konus-Wind observation of GRB 170808B
- LIGO/Virgo G296853: Super-AGILE observations
- LIGO/Virgo G296853: MASTER SN detection near center error-area
- GRB 170805B: Insight-HXMT observation
- GRB 170803B: Insight-HXMT detection
- Konus-Wind observation of GRB 170805B
- GMRT upper limit on the radio afterglow of GRB 170728B
- LIGO/Virgo G296853: no INTEGRAL data at the time of the event
- LIGO/Virgo G296853: Fermi-LAT search for high-energy gamma-ray counterpart
- LIGO/Virgo G296853: Fermi GBM Observations
- LIGO/Virgo G296853: AGILE GRID observations
- LIGO/Virgo G296853: Swift/BAT data search
- LIGO/Virgo G296853: MASTER follow up observations
- LIGO/Virgo G296853: AGILE MCAL observations
- LIGO/Virgo G296853 ANTARES search
- LIGO/Virgo G296853: IceCube neutrino observations
- LIGO/Virgo G296853: Identification of a GW Binary Merger Candidate
- GRB 170808B: Fermi LAT Detection
- GRB 170808B: Fermi GBM observation
- IPN Triangulation of GRB 170805B (short/hard)
- IPN Triangulation of GRB 170805A (short)
- GRB 170801A: Insight-HXMT detection
- Konus-Wind observation of GRB 170724A
- GRB 170714A: ATCA detection of the radio counterpart
- GRB 170807A: Swift-BAT refined analysis
- GRB 170808A: MAXI/GSC detection
- GRB 170805A: Insight-HXMT detection
- GRB 170807A: Swift detection of a burst
- GRB 170728B: TShAO, SAO RAS and AbAO optical observations
- GRB 170803A: Swift/BAT spectral lag results
- GRB 170804A: LCO Observations
- GRB 170804A: Swift-BAT refined analysis
- GRB 170804A: Swift/UVOT Detection
- GRB 170804A: Swift-XRT refined Analysis
- GRB 170804A: Enhanced Swift-XRT position
- GRB 170803A: Swift-BAT refined analysis
- GRB 170803A: Swift/UVOT Detection
- GRB 170804A: Swift detection of a burst with optical counterpart
- Swift Trigger 766161 is not a GRB
- GRB 170803A: Swift-XRT refined Analysis
- GRB 170803A: Enhanced Swift-XRT position
- GRB 170803A: Fermi GBM observation
- GRB 170803A: Swift detection of a burst with an optical counterpart
- GRB 170802A: Fermi GBM detection
- Swift Trigger 765783 is not an astrophysical event.
- GRB 160814A: Lomonosov BDRG gamma ray discovery