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"27767 results found.
- Swift GRB230311.84: Global MASTER-Net observations report
- Swift Trigger 1159438 is also due to the Star Tracker loss of lock.
- Swift GRB230311.82: Global MASTER-Net observations report
- Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
- TESS Detection of the Optical Afterglow of GRB230307A
- GRB 230308A: CALET Gamma-Ray Burst Monitor detection
- Trigger 1159327: Swift detection of SGR1806-20
- GRB 230310A: AstroSat CZTI detection
- GRB 230307A: MAXI/GSC upper limit
- GRB 230310A: Fermi GBM Final Real-time Localization
- GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
- GRB 230307A: Erratum of the GCN 33441
- GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
- GRB 230308A: Fermi GBM detection
- GRB 230307A: Possible optical afterglow
- GRB 230307A: ASO-S/HXI detection
- GRB 230307A: AstroSat LAXPC detection
- GRB 230308A: AGILE/MCAL detection
- GRB 230307A: optical upper limit
- GRB 230217A: ATCA rapid-response radio detection
- Swift Trigger 1159108 is not a GRB
- GRB 230307A: Swift/BAT upper limits on the early afterglow
- GRB 230307A: Swift-XRT observations
- Konus-Wind detection of GRB 230307A
- Improved IPN localization for GRB 230307A
- GRB 230307A: VZLUSAT-2 detection
- GRB 230304B: CALET Gamma-Ray Burst Monitor detection
- GRB 230308A: Fermi GBM Final Real-time Localization
- GRB 230307A: Tiled Swift observations
- GRB 230307A: Detection by GRBAlpha
- GRB 230305A: Detection by GRBAlpha
- GRB 230307A: AstroSat CZTI detection
- GRB 230307A: possibly the second highest GRB energy fluence ever identified
- IPN triangulation of GRB 230307A (long/very bright)
- GRB 230307A: AGILE/MCAL detection
- GRB 230307A: Fermi GBM detection of a very bright GRB
- GRB 230307A: GECAM detection of an extremely bright burst
- GRB 230307A: Fermi GBM Final Real-time Localization
- IceCube-230306A - IceCube observation of a high-energy neutrino candidate
- GRB 230304C: AstroSat CZTI detection
- GRB 230304B: AstroSat CZTI detection
- GRB 230304A: AstroSat CZTI detection
- GRB 230304B: Detection by GRBAlpha
- GRB 230304C: Fermi GBM Final Real-time Localization
- GRB 230304B: Fermi GBM Final Real-time Localization
- GRB 230304A: Fermi GBM Final Real-time Localization
- GRB 230228A: Swift-BAT refined analysis
- GRB 230228A: Swift/UVOT Upper Limits
- GRB 230301B: Fermi GBM Final Real-time Localization
- GRB 230228A: Fermi GBM Observation
- GRB 230228A: OSN optical upper limit
- GRB 230301A: Fermi GBM Final Real-time Localization
- GRB 230228A: Swift-XRT refined Analysis
- GRB 230228A: Mondy optical upper limit
- GRB 230228A: Enhanced Swift-XRT position
- GRB 230228A: Nanshan/NEXT optical upper limit
- GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
- GRB 230228A: Prompt enhanced Swift-XRT position
- GRB 230228A: Swift detection of a possibly short burst
- GRB 230227A: Fermi GBM Final Real-time Localization
- GRB 230216A Mondy Observations
- GRB 230217A: Swift/UVOT Upper Limits
- GRB 230216A: Swift/UVOT Upper Limits
- GRB 230222A: Fermi GBM Final Real-time Localization
- GRB 230217A: Swift-XRT afterglow detection
- GRB 230217A: Swift-BAT refined analysis
- GRB 230217A: AstroSat CZTI detection
- GRB 230217A: Gemini South optical upper limits
- GRB 230216B: CALET Gamma-Ray Burst Monitor detection
- GRB 230217A: 6 GHz VLA observations
- GRB 230220B: Fermi GBM Final Real-time Localization
- IceCube-230220A - IceCube observation of a high-energy neutrino candidate
- GRB 230217A: Fermi GBM observation
- GRB 230220A: MAXI/GSC detection
- Konus-Wind detection of GRB 230217A
- GRB 230217A: Swift-XRT observations
- GRB 230218A: Fermi GBM Final Real-time Localization
- GRB 230217A: AGILE/MCAL detection
- GRB 230207B: CALET Gamma-Ray Burst Monitor detection
- GRB 230216B: AstroSat CZTI detection
- GRB 230216A: SVOM/C-GFT optical upper limit
- GRB 230217A: Swift detection of a short burst
- GRB 230217A: Fermi GBM Final Real-time Localization
- IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 230216A: Swift-BAT refined analysis
- GRB 230216A: Swift-XRT refined Analysis
- Swift GRB 230216A: Global MASTER-Net observations report
- GRB 230216A: Enhanced Swift-XRT position
- GRB 230216A: AKO Upper Limit
- GRB 230216A: Zadko observatory - Gingin optical observations
- GRB 230216A: Swift detection of a burst
- GRB 230215A: Fermi GBM Final Real-time Localization
- GRB 230209B: AGILE detection
- GRB 230209B: Fermi GBM Observation
- IPN triangulation of GRB 230209B
- GRB 230204B: CALET Gamma-Ray Burst Monitor detection
- GRB 230204B: ATCA radio detection
- Outburst from LS V +44 17 / RX J0440.9+4431: Transient detection by GRBAlpha
- GRB 230211A: Fermi GBM Final Real-time Localization
- GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV