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"
3821 results found.
- GRB 240229A: Fermi GBM Final Real-time Localization
- GRB 240225B: VLT/X-shooter redshift
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: MAXI/GSC detection
- Transient EPW20240219aa: Mondy optical observations
- Fermi trigger No 729914426: Global MASTER-Net observations report
- Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
- Fermi trigger No 729650855: Global MASTER-Net observations report
- Fermi GRB 240213A: Global MASTER-Net observations report
- Fermi trigger No 729152364: Global MASTER-Net observations report
- Fermi trigger No 729012023: Global MASTER-Net observations report
- GRB 240204A: Mondy optical afterglow observations
- Fermi trigger No 728749569: Global MASTER-Net observations report
- GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
- Fermi GRB 240204A: Global MASTER-Net observations report
- Fermi trigger No 728706420: Global MASTER-Net observations report
- IceCube Alert 240204.38: Global MASTER-Net observations report
- GRB 240129A: Fermi GBM Observation
- Fermi GRB 240127A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240119A (short/hard)
- IPN triangulation of GRB 240119A (short)
- GRB 240119A: GECAM detection of a short burst
- GRB 240119A: AstroSat CZTI detection of a short burst
- GRB 240118A: Mondy optical observations
- GRB 240119A: Fermi GBM Final Localization
- GRID detection of GRB 231230A
- IPN triangulation of GRB 240112A (long)
- GRB 240112C: Swift/UVOT Detection
- Fermi trigger No 726773850: Global MASTER-Net observations report
- GRB 240112C: Swift-XRT refined Analysis
- Fermi trigger No 726774492: Global MASTER-Net observations report
- GRB 240112C: Swift detection of a burst with an optical counterpart
- GRB 240112A: GECAM detection of a burst
- GRB 230812B: further radio observations with the VLA
- GRB 240107A: MAXI/GSC detection
- LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate
- IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
- Fermi trigger No 725806648: Global MASTER-Net observations report
- GRB231230A: Fermi GBM Observation
- Fermi trigger No 725592555: Global MASTER-Net observations report
- GRB 231230A: Swift detection of a burst
- GRB 231230A: Fermi GBM Final Real-time Localization
- Fermi trigger No 724781422: Global MASTER-Net observations report
- GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231205B: VZLUSAT-2 detection
- Konus-Wind detection of GRB 231210B
- Swift GRB231215.41: Global MASTER-Net observations report
- Fermi trigger No 724278269: Global MASTER-Net observations report
- GRB 231210B: Swift detection of a burst with optical counterpart
- IPN triangulation of GRB 231129C
- GRB 231208A: GRBAlpha detection
- GRB 231208A: Glowbug gamma-ray detection
- GRB 231208A: AstroSat CZTI detection of a faint burst
- GRB 231205B: REM optical/NIR upper limits
- GRB 231129C: ASIM MXGS observation and localization
- GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 231205B : MITSuME Akeno optical upper limits
- Fermi trigger No 723435916: Global MASTER-Net observations report
- Fermi trigger No 723326169: Global MASTER-Net observations report
- Fermi trigger No 723149952: Global MASTER-Net observations report
- GRB 231129A: VZLUSAT-2 detection
- GRB 231129C: AGILE detection
- GRB 231129A : MITSuME Akeno optical upper limits
- GRB 231129C: MASTER OT detection
- GRB 231129A: BOOTES-5/JGT optical upper limit
- GRB 231129C: Fermi-LAT detection
- GRB 231129A: JinShan optical upper limit
- GRB 231129C: GRBAlpha detection
- GRB 231129C: Glowbug gamma-ray detection
- GRB 231129A: optical upper limit in Mondy observatory
- GRB 231129C: AstroSat CZTI detection
- GRB 231129C: CALET Gamma-Ray Burst Monitor detection
- GRB 231129C: Fermi GBM Observation of a very bright GRB
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129C: MAXI/GSC detection
- GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
- GRB 231129C: Fermi GBM detection of a very bright burst
- GRB 231129C: Fermi GBM Final Real-time Localization
- Fermi trigger No 722977823: Global MASTER-Net observations report
- GRB 231129B: MAXI/GSC detection
- Integral GRB231129.21: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
- Fermi trigger No 722507896: Global MASTER-Net observations report
- Fermi trigger No 722462310: Global MASTER-Net observations report
- Fermi trigger No 722349867: Global MASTER-Net observations report
- GRB 231117A : MITSuME Akeno optical afterglow candidate detection
- GRB 231118A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
- GRB 231117A: AKO Optical Upper Limit
- Swift GRB 231117A: Global MASTER-Net observations report
- GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
- GRB 231115A : MITSuME Akeno and Okayama optical upper limits
- GRB 231115A: archival HST observations
- GECAM-B observation of a short burst from SGR J1555-5402
- SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
- GRB 231111A: GMG observation (correction)
- GRB 231111A: GMG observation upper limit
- Fermi GRB 231108A: Global MASTER-Net observations report
- Fermi GRB 231106A: Global MASTER-Net observations report
- GRB 231104A: 3.6m DOT optical upper limit