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"3040 results found.
- Fermi trigger No 737788024: Global MASTER-Net observations report
- Fermi trigger No 737559855: Global MASTER-Net observations report
- GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
- Fermi trigger No 737523389: Global MASTER-Net observations report
- LAT GRB240513.31: Global MASTER-Net observations report
- Fermi trigger No 737277727: Global MASTER-Net observations report
- Fermi trigger No 737258655: Global MASTER-Net observations report
- Fermi trigger No 737247400: Global MASTER-Net observations report
- Fermi trigger No 737196587: Global MASTER-Net observations report
- Fermi trigger No 737152719: Global MASTER-Net observations report
- Fermi trigger No 736967879: Global MASTER-Net observations report
- Fermi trigger No 736564880: Global MASTER-Net observations report
- IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
- GRB 240502C: GOTO possible optical counterpart candidates
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
- Fermi GRB 240501A: Global MASTER-Net observations report
- Fermi trigger No 736197684: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
- LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
- IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
- LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
- GRB 240421B: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
- LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
- LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
- IceCube Alert 240424.08: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
- GRB 240419A: Swift-BAT refined analysis
- GRB 240421B: ATCA radio observations
- LIGO/Virgo/KAGRA S240422ed: Magellan Observations
- Fermi trigger No 735470374: Global MASTER-Net observations report
- Fermi trigger No 735280430: Global MASTER-Net observations report
- IceCube Alert 240419.98: Global MASTER-Net observations report
- GRB 240411A: GOTO early optical upper limits
- Fermi GRB 240417A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
- EP240416A: Khureltogoot optical upper limit
- Improved IPN triangulation of GRB 240411A
- EP240416A: MASTER optical observations
- GRB 240414A: Swift-BAT refined analysis
- Fermi GRB 240415A: Global MASTER-Net observations report
- GRB 240415A: Fermi GBM Final Real-time Localization
- Fermi trigger No 734754044: Global MASTER-Net observations report
- GRB 240414A : OHP/T193 redshift determination
- LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
- IceCube Alert 240412.23: Global MASTER-Net observations report
- EP240408a: Swift follow-up observation
- Fermi GRB 240405B: Global MASTER-Net observations report
- GRB 240403B: Glowbug gamma-ray detection
- GRB 240403A: Glowbug gamma-ray detection
- Konus-Wind detection of LXT 240402A/GRB 240402B
- GRB 240403A: Fermi GBM Detection
- GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
- Fermi GRB 240402A: Global MASTER-Net observations report
- Fermi trigger No 733097506: Global MASTER-Net observations report
- Fermi GRB 240320A: Global MASTER-Net observations report
- Fermi GRB 240317B: Global MASTER-Net observations report
- Fermi trigger No 732299243: Global MASTER-Net observations report
- Fermi GRB 240314A: Global MASTER-Net observations report
- Fermi GRB 240310A: Global MASTER-Net observations report
- Fermi GRB 240306A: Global MASTER-Net observations report
- Fermi GRB 240305A: Global MASTER-Net observations report
- Swift J151857.0-572147: Swift-BAT refined analysis
- Fermi GRB 240229A: Global MASTER-Net observations report
- IceCube Alert 240229.66: Global MASTER-Net observations report
- Fermi trigger No 730618809: Global MASTER-Net observations report
- GRB 240216A: Glowbug gamma-ray detection
- GRB 240218A: Swift-BAT refined analysis
- GRB 240215A: Fermi GBM Observation
- GRB 240216A: GRBAlpha detection
- Fermi trigger No 729914426: Global MASTER-Net observations report
- GRB 240216A: Fermi GBM Final Real-time Localization
- GRB 240214A/1H 0451-560: MAXI/GSC detection
- Fermi trigger No 729152364: Global MASTER-Net observations report
- Fermi trigger No 729012023: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240205B (long / very soft)
- GRB 240204A: Swift-BAT refined analysis
- Fermi trigger No 728749569: Global MASTER-Net observations report
- GRB 240204a: Liverpool Telescope optical afterglow detection
- IceCube Alert 240123.48: Global MASTER-Net observations report
- Swift triggers 1209631, 1209632, 1209635 and 1209644 are not interesting astrophysical events
- AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
- Swift Triggers 1209371 through 1209374 are not astrophysical events
- Fermi GRB 240115A: Global MASTER-Net observations report
- GRB 240114A: MAXI/GSC detection
- Fermi GRB 240112D: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240101C
- GRB 231215A: radio detection with the VLA
- Swift GRB240109.17: Global MASTER-Net observations report
- IPN triangulation of GRB 240101C (short)
- GRB GRB240101C: Fermi GBM observation
- GRB 240101C: Swift/BAT-GUANO detection of a short burst
- GRB 240101C: AstroSat CZTI detection
- GRB 240101C: GRBAlpha detection
- GRB 240101C: Fermi GBM Final Localization
- Swift GRB240101.85: Global MASTER-Net observations report
- Fermi trigger No 725806648: Global MASTER-Net observations report
- Fermi trigger No 725592555: Global MASTER-Net observations report