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 200901A: Swift-XRT observations
- GRB 200901A: Swift detection of a burst
- Swift GRB200901.16: Global MASTER-Net observations report
- GRB 200829A: Koshka Zeiss-1000 optical observations
- Fermi GBM trigger 620564765/200831463 is not a GRB
- GRB 200829A: Liverpool Telescope observations
- GRB 200829A: Continued Nanshan/NEXT optical observations
- GRB 200829A: Kitab optical upper limit
- GRB 200829A: further SAO RAS optical observations
- Fermi GRB 200830A: Global MASTER-Net observations report
- GRB 200829A: Fermi GBM detection
- GRB 200829A: Swift-BAT refined analysis
- GRB 200829A: Nanshan/NEXT optical observations
- Konus-Wind detection of GRB 200829A (a clone of GRB 200826B?)
- GRB 200829A: SAO RAS optical observations
- GRB 200830A: BALROG localization (Fermi Trigger 620474063 / GRB 200830413)
- GRB 200830A: Fermi GBM Final Real-time Localization
- GRB 200826A
- GRB 200829A: THO optical observatios
- GRB 200829A: Swift-XRT refined Analysis
- GRB200829A: optical afterglow detection
- GRB 200829A: Global MASTER-Net OT detection
- GRB 200829A: AGILE/MCAL detection
- GRB 200829A: Enhanced Swift-XRT position
- GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
- GRB 200829A: Swift/UVOT Detection
- Fermi trigger No 620402299: Global MASTER-Net observations report
- Swift GRB 200829A: Global MASTER-Net observations report
- GRB 200829A: TSHAO optical observations
- 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