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.
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"26339 results found.
- GECAM detection of a short burst from SGR 1935+2154
- GRB 210707A: A long GRB detected by INTEGRAL
- GRB 210708A: Swift detection of a burst
- Fermi trigger No 647271699: Global MASTER-Net observations report
- GRB 210706A: Fermi GBM observation
- GRB 210706A: GIT optical upper limits
- GRB 210704A: OAJ T80 multi-color detections
- GECAM detection of a bright short burst from SGR 1935+2154
- GRB 210706A: Swift-XRT afterglow detection
- GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
- GRB 210704A: OSIRIS/GTC spectroscopy
- GRB 210704A: RATIR optical upper limits
- GRB 210704A: Swift/UVOT Upper Limits
- GRB 210704A: TNG detection of the optical afterglow candidate
- GRB 210704A: Assy optical afterglow candidate
- GRB 210704A: DDOTI upper limit
- GRB 210704B: Fermi GBM detection
- GRB 210704A: possible local hosts
- GRB 210704A: Fermi GBM detection
- GRB 210704A: Swift-XRT afterglow detection
- IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Fermi trigger No 647108723: Global MASTER-Net observations report
- Fermi trigger No 647120009: Global MASTER-Net observations report
- GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
- GRB 210702A, Swift-BAT refined analysis
- GRB 210702A: Chilescope optical observations
- GRB 210702A: iTelescope optical afterglow observations
- GRB 210702A: Swift-XRT refined Analysis
- GRB 210702A: VLT/X-shooter redshift
- GRB 210702A: preliminary Swift/UVOT photometry
- GRB210702A: MeerLICHT multi-colour photometry
- Swift GRB210702.80: Global MASTER-Net OT detection
- GRB 210702A: Swift detection of a burst with a bright optical counterpart
- IceCube-210629A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Fermi-LAT Gamma-ray Observations of IceCube-210629A
- GRB 210627B: GECAM detection
- GRB 210619B: Sayan observatory 1.6-m telescope observations
- GRB 210626A: GIT optical upper limit
- GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
- GRB 210626A: Swift-XRT afterglow detection
- Fermi trigger No 646322348: Global MASTER-Net observations report
- GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
- GRB210619B: optical afterglow detection from Konkoly Observatory
- GRB 210622A: Swift-XRT observations
- GRB 210610B: T-CAT optical observations
- GRB 210619B: ASIM observation
- GRB 210618A: Swift-XRT afterglow detection
- GRB 210619B: Even further SAO RAS optical observations
- GRB 210619B: Mini-MegaTORTORA early optical observations
- GRB 210622A: Fermi GBM detection
- GRB 210619B: Further SAO RAS optical observations
- GRB 210622A: Swift/BAT-GUANO detection and arcminute localization of a long burst
- GRB 210619B: possibility of lensed visible afterglow?
- GECAM detection of GRB 210622B
- GRB 210619B: AbAO optical observations
- Swift Trigger 1057131: detection of a burst from SGR Swift J1555.2-5402
- Swift GRB210621.71: Global MASTER-Net observations report
- GRB 210619B: iTelescope optical afterglow observation
- GRB 210619B: SAO RAS optical observations
- GRB 210619B: SEDM Optical Observations
- GRB 210619B: REM optical/NIR afterglow detection
- GRB 210619B: GIT optical follow-up and confirmation of jet-break
- GRB 210619B: Swift-BAT refined analysis
- GRB 210619B: Liverpool Telescope First Hour Observations
- GRB 210619B: Fermi GBM detection
- GRB 210619B: Swift/UVOT Detection
- GRB 210619B: Liverpool telescope imaging of a red afterglow
- GRB 210619B: Swift-XRT refined Analysis
- GRB 210619B: SARA-KP 0.9m Optical Afterglow Detection
- GRB 210619B: Enhanced Swift-XRT position
- GRB 210619B: iTelescope T18 detection
- GECAM detection of GRB 210619B
- Swift GRB210619.99: Global MASTER-Net OT detection
- GRB 210619B: Swift detection of a bright burst and optical counterpart
- Swift GRB210619.99: Global MASTER-Net OT detection
- GRB 210619A: BALROG localization (Fermi Trigger 645799548 / GRB 210619532)
- GRB 210618A: Swift/UVOT Upper Limits
- GRB 210618A: Swift-BAT refined analysis
- GRB 210618A: Fermi GBM observation
- GRB 210618A: Swift-XRT observations
- GRB 210618A: DDOTI upper limit for the optical afterglow
- GRB 210618A: Swift detection of a burst
- GRB 210610B: Swift/UVOT Detection
- GRB 210610A: Swift/UVOT Detection
- GRB 210323B: Fermi GBM observation
- GRB 210610B: REM optical/NIR observations of the afterglow
- Follow-up on HAWC Transient Monitoring Alert J0020+3108
- Swift ToO Observations of HAWC transient J0020+3108
- GRB 210605B: Swift-XRT afterglow detection
- GRB 210610A: Fermi GBM observations
- GRB 210610B: Further SAO RAS optical observations
- GRB 210610A: SAO RAS optical observations
- GRB 210610B: optical photometry of afterglow at INASAN/Simeiz
- GRB 210421B: Fermi GBM detection
- GRB 210607C: AstroSat CZTI detection
- Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
- GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
- GRB 210610B: MITSuME Akeno optical observation