GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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 200829A: Swift detection of a burst with an optical afterglow
- GRB 200826A: Kitab optical observations
- Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
- Konus-Wind detection of GRB 200826B
- IPN triangulation of GRB 200826B
- GRB 200826A: VLA Detection at 6 GHz
- GRB 200826A: further analysis of the Konus-Wind data and classification
- GRB 200826A: Swift-XRT afterglow detection
- GRB 200824A: Insight-HXMT/HE detection
- GRB 200826B: Fermi GBM detection
- Fermi GRB 200826B: Global MASTER-Net observations report
- Fermi GRB 200824A: Global MASTER-Net observations report
- GRB200826A: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi Short GRB (Trigger 620108997)
- Konus-Wind detection of GRB 200826A
- GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
- GRB 200826B: Fermi GBM Final Real-time Localization
- IPN triangulation of GRB 200826A (short/bright)
- GRB 200826A: Tiled Swift observations
- GRB 200826A: AGILE detection
- GRB 200826A: AstroSat CZTI detection
- GRB 200826A: Fermi GBM observation
- GRB 200826A: BALROG localization (Fermi Trigger 620108997 / GRB 200826187)
- Fermi GRB 200826A: Global MASTER-Net observations report
- GRB 200826A: Fermi GBM Final Real-time Localization
- GRB 200824A: Fermi GBM Final Real-time Localization
- Swift Trigger 992444 is due to detector noise
- GRB 200819A: Swift/UVOT Upper Limits
- Swift GRB200821.55: Global MASTER-Net observations report
- IceCube-200806A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Swift Trigger 992444: a possible GRB 200821A
- Konus-Wind observation of GRB 200815A
- GRB 200819A: Swift-BAT refined analysis
- GRB 200815A: MASTER optical observations
- IPN triangulation of GRB 200815A (short)
- GRB 200819A: Optical Observations from HCT
- GRB 200819A: Swift-XRT refined Analysis
- GRB 200819A: MITSuME Ishigaki optical upper limits
- GRB 200729A: Lowell Discovery Telescope observations
- GRB 200819A: MITSuME Akeno optical upper limits
- Baksan Neutrino Observatory Alert 200819.88: Global MASTER-Net observations report
- GRB 200819A / Swift J0125.7+6303: Ondrejov Perek-2m optical limit
- GRB 200819A: Kitab, TSHAO optical upper limit
- GRB 200819A: Enhanced Swift-XRT position
- Swift GRB 200819A: Global MASTER-Net observations report
- GRB 200819A: Swift detection of a burst
- Baksan Neutrino Observatory Alert 200819.09: Global MASTER-Net observations report
- GRB 200818A: Fermi GBM Final Localization
- Fermi trigger No 619487843: Global MASTER-Net observations report
- Swift Trigger 990358 is due to detector noise
- Swift Trigger 989458 is due to detector noise
- HAWC-200814A: Retraction of burst alert
- Fermi GRB 200817A: Global MASTER-Net observations report
- GRB 200815A: CALET Gamma-Ray Burst Monitor detection of a short burst
- GRB 200817A: Fermi GBM Final Real-time Localization
- Swift trigger 990358 is not an astrophysical source
- Swift GRB200816.17: Global MASTER-Net observations report
- Fermi trigger No 619270776: Global MASTER-Net observations report
- Swift trigger 989458 is likely not an astrophysical source
- HAWC alert 200815.26: MASTER optical observations
- Alert from the HAWC Burst Monitor HAWC-200814A
- IceCube200806A: No significant detection in HAWC
- GRB 200811A: Fermi GBM Final Real-time Localization
- GRB 200811A: BALROG localization (Fermi Trigger 618851447 / GRB 200811632)
- GRB 200809B: Fermi GBM detection
- Fermi GRB 200809B: Global MASTER-Net observations report
- GRB 200809B: BOOTES-3/YA optical upper limit
- GRB 200809B: Swift-XRT afterglow detection
- GRB 200809B: MAXI/GSC detection
- GRB 200809B: Swift ToO observations
- GRB 200809B: AstroSat CZTI detection
- GRB 200809B: Swift/BAT-GUANO detection and arcminute localization
- GRB 200809B: Fermi GBM Final Real-time Localization
- GRB 200808A: AGILE detection
- GRB 200806A: CALET Gamma-Ray Burst Monitor detection
- Fermi trigger No 618642276: Global MASTER-Net observations report
- GRB 200809A: Fermi GBM Final Real-time Localization
- Fermi GRB 200808A: Global MASTER-Net observations report
- GRB 200808A: Fermi GBM Final Real-time Localization
- GRB 200806A: Nanshan/NEXT optical upper limit
- IPN triangulation of GRB 200805A (short)
- GRB 200806A: CAHA optical afterglow confirmation
- GRB 200803A: Chilescope optical upper limit
- IceCube-200806A: Upper limits from a search for additional neutrino events in IceCube
- GRB 200806A: VIRT optical observations
- GRB 200806A: Swift-BAT refined analysis
- GRB 200806A: Swift/UVOT Possible Detection
- GRB 200806A: Swift-XRT refined Analysis
- Fermi-LAT Gamma-ray Observations of IceCube-200806A
- CGBM-SPI-ACS triangulation of short GRB 200805A
- GRB 200806A: AbAO optical upper limit
- GRB 200805A: CALET Gamma-Ray Burst Monitor detection of a short burst
- GRB 200806A: AstroSat CZTI detection
- GRB 200806A: MITSuME Akeno optical upper limits
- GRB 200806A: Enhanced Swift-XRT position
- IceCube-200806A: Upper limits from Fermi-GBM Observations
- Swift GRB 200806A: Global MASTER-Net observations report
- GRB 200806A: Swift detection of a burst
- IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
- IceCube Alert 200806.58: Global MASTER-Net observations report
- GRB 200803B: MASTER possibly OT discovery