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').
- GRB 220210A: Insight-HXMT/HE detection
- GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
- GRB 220210A: 1.5m OSN optical upper limit
- GRB 220210A: Fermi GBM detection
- Fermi GRB 220211B: Global MASTER-Net observations report
- GRB 220211B: Fermi GBM Final Real-time Localization
- GRB 220209A: Fermi-LAT detection
- GRB 220210A: Fermi-LAT detection
- GRB 220210A: AGILE detection
- GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
- GRB 220210A: BOOTES-5/JGT optical afterglow candidate
- GRB 220210A: Swift/BAT-GUANO localization
- Fermi GRB 220211A: Global MASTER-Net observations report
- GRB 220211A: Fermi GBM Final Real-time Localization
- Fermi GRB 220210A: Global MASTER-Net observations report
- GRB 220210A: Fermi GBM Final Real-time Localization
- GRB 210919A: Maidanak optical observations
- GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
- GRB 220209A: Fermi GBM Detection
- GRB 220209A: GECAM detection
- GRB 220209A: AGILE/MCAL detection
- Fermi GRB 220209A: Global MASTER-Net observations report
- GRB 220209A: Fermi GBM Final Real-time Localization
- IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
- IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
- Fermi-LAT Gamma-ray Observations of IceCube-220205B
- Fermi-LAT Gamma-ray Observations of IceCube-220205A
- IceCube-220205B: No neutrino counterpart candidates in ANTARES search
- Konus-Wind detection of GRB 220130A
- IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
- Konus-Wind detection of GRB 220203A
- GRB 220203A: GECAM detection
- IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220203A: Swift/BAT-GUANO detection outside the coded FOV
- IPN triangulation of GRB 220203A (short)
- IPN triangulation of GRB 220130A
- Swift Reaction Wheel Anomaly Update (4 Feb 2022)
- Fermi-LAT Gamma-ray Observations of IceCube-220202A
- IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
- GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
- IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
- IceCube Alert 220202.49: Global MASTER-Net observations report
- GRB 220131B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220201A: Fermi GBM Final Localization
- GRB 220128A: AstroSat CZTI detection
- GRB 220130A: Fermi GBM Observation
- Konus-Wind detection of GRB 220128A
- IPN triangulation of GRB 220128A (long)
- Fermi GRB 220131A: Global MASTER-Net observations report
- GRB 220131B: GECAM detection
- GRB 220130A: GECAM detection
- GRB 220131A: Fermi GBM Final Real-time Localization
- Fermi GRB 220129A: Global MASTER-Net observations report
- GRB 220129A: Fermi GBM Final Real-time Localization
- IceCube-211208A: the optical observation of the candidate PKS0735+178
- GRB 220127A: GECAM detection
- GECAM observations of a series of bursts from SGR J1935+2154
- Konus-Wind detection of GRB 220124A
- IPN triangulation of GRB 220124A
- GRB 220124A: GECAM detection
- Fermi trigger No 664738369: Global MASTER-Net observations report
- GRB 220117A, GROND observations
- GRB 220124A: AstroSat CZTI detection of a bright long GRB
- GRB 220117A: Terskol and AbAO optical upper limits
- GRB 220118A: TARGET optical upper limit
- GRB 220117B: TARGET optical upper limit
- GRB 220121B: GECAM detection
- Fermi-LAT-ANTARES 220121a: upper limits from a search for coincident neutrinos with IceCube
- AGILE observations of a bright burst from SGR 1935+2154
- Fermi-LAT-ANTARES 220121a Coincidence
- Konus-Wind detection of an intermediate flare from SGR 1935+2154 on January 20
- IPN triangulation of a bright burst from SGR 1935+2154
- GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
- IPN triangulation of GRB 211226A
- GRB 220120A: Fermi GBM Final Localization
- GRB 220117C: Fermi GBM Observation
- GRB 220118A: 2.2m CAHA/CAFOS detections
- GRB 220118A: Fermi GBM detection
- GRB 220118A: COATLI Optical Observations
- GRB 220101A: KAO optical-R observation
- GRB 211221A: No V & R detection, KAO telescope
- GRB 220118A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
- GRB 220117C: Swift/BAT-GUANO arcminute localization
- Swift currently in safe hold with science slews disabled
- GRB 220118A: Swift-BAT refined analysis
- GRB 220118A: Swift/UVOT Detection
- Konus-Wind observation of the recent SGR 1935+2154 activity
- GRB 220118A: GIT optical observations
- GRB 220118A: Enhanced Swift-XRT position
- Swift GRB220118.50: Global MASTER-Net observations report
- GRB 220118A: MITSuME Akeno optical observation
- GRB 220117B: z-band limit
- Swift GRB 220118A: Global MASTER-Net observations report
- GRB 220118A: Swift detection of a burst with an optical counterpart
- GRB 220118A: Fermi GBM Final Real-time Localization
- GRB 220117A: MITSuME Akeno optical upper limits
- Fermi GBM Sub-Threshold Detection of GRB 220117A
- GRB 220117B: Swift-BAT refined analysis
- GRB 220117A: Swift-BAT refined analysis
- IceCube-220115A: Upper limits from a search for additional neutrino events in IceCube