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').
- VIRT optical transient detection
- GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
- GRB 230307A: iTelescope optical upper limit (likely)
- GRB 230414B: Montarrenti Observatory late time optical afterglow detection
- IceCube-230416A: IceCube observation of a high-energy neutrino candidate
- Fermi trigger No 703284533: Global MASTER-Net observations report
- GRB 230414B: Lulin 40cm-SLT optical limit
- GRB 230414B: Bassano Bresciano Observatory optical observations
- GRB 230414B: Redshift from OSIRIS/GTC
- GRB 230414B: AbAO optical observations
- GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
- GRB 230414B: Swift-XRT refined Analysis
- GRB 230414B: Dabancheng/GHOST optical observations
- AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230414A
- GRB 230414B: slow optical light curve decay
- GRB 230414B: SAO RAS optical observations
- GRB 230414B: Enhanced Swift-XRT position
- GRB 230414B: 1.3m DFOT Optical observations
- Fermi GRB 230414A: Global MASTER-Net observations report
- GRB 230414B: GROWTH India Telescope afterglow confirmation
- GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
- GRB 230414B: Nanshan/HMT optical afterglow detection
- GRB 230414A: Mondy optical afterglow candidate
- Swift GRB 230414B: Global MASTER-Net observations report
- GRB 230414B: Prompt enhanced Swift-XRT position
- GRB 230414B: Swift detection of a burst
- IceCube-230405A: BOOTES-4/MET Optical Upper Limits
- GRB 230414A: Fermi GBM Final Real-time Localization
- GRB 230328B: redshift lower limit estimating
- GRB 230409B: Mondy optical upper limit
- GRB 230409B: OHP/T193 optical upper limit
- GRB 230410B: VZLUSAT-2 detection
- GRB 230409D: VZLUSAT-2 detection
- GRB 230410B: AGILE detection of a burst
- GRB 230410A: Fermi GBM Final Real-time Localization
- Fermi GRB 230409C: Global MASTER-Net observations report
- Fermi GRB 230409A: Global MASTER-Net observations report
- GRB 230409C: Fermi GBM Final Real-time Localization
- GRB 230409B: Swift-XRT refined Analysis
- GRB 230409B: Swift-BAT refined analysis
- Fermi trigger No 702745263: Global MASTER-Net observations report
- Swift GRB 230409B: Global MASTER-Net observations report
- GRB 230409B: Swift/UVOT Detection
- GRB 230409B: Enhanced Swift-XRT position
- MAXI GRB230408.82: Global MASTER-Net observations report
- GRB 230409B: Swift detection of a burst
- GRB 230409A: Fermi GBM Final Real-time Localization
- GRB 230405B: VZLUSAT-2 detection
- IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
- Fermi-LAT gamma-ray observations of IceCube-230405A
- Konus-Wind detection of GRB 230405B
- GRB 230405B: AGILE detection
- GRB 230405B: Swift-XRT refined Analysis
- GRB 230405B: Fermi GBM Observation
- GRB 230405B: MeerLICHT upper limits
- IceCube Alert 230405.56: Global MASTER-Net observations report
- GRB 230307A: JWST NIRSpec observations, possible higher redshift
- GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
- GRB 230307A: good match with kilonova models
- GRB 230307A: short mininum variability timescale compatible with a merger origin
- GRB 230405B: Swift/UVOT Upper Limits
- GRB 230405B: AstroSat CZTI detection
- GRB 230405B: Enhanced Swift-XRT position
- Swift GRB 230405B: Global MASTER-Net observations report
- GRB 230405B: Prompt enhanced Swift-XRT position
- GRB 230405B: Swift detection of a burst
- GRB 230405B: Fermi GBM Final Real-time Localization
- GRB 230307A: JWST observations consistent with the presence of a kilonova
- Fermi GRB 230405A: Global MASTER-Net observations report
- IceCube-230405A: IceCube observation of a high-energy neutrino candidate
- GRB 230405A: Fermi GBM Final Real-time Localization
- GRB 230404A: AstroSat CZTI detection
- GRB 230404A: Fermi GBM Final Real-time Localization
- GRB 230402A: CALET Gamma-Ray Burst Monitor detection
- GRB 230402A: AstroSat CZTI detection
- Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
- IceCube-230401A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230328B: Multa observatory optical afterglow observation
- GRB 230307A: Chandra late-time detection of the X-ray afterglow
- GRB 230228A: detection by GTC of the potential host galaxy
- GRB 230328B: Swift/UVOT Detection
- GRB 230402A: AGILE detection
- Fermi GRB 230402A: Global MASTER-Net observations report
- GRB 230402A: Fermi GBM Final Real-time Localization
- IceCube-230401A: IceCube observation of a high-energy neutrino candidate
- GRB 230307A: Bad Time Intervals for Fermi GBM data
- GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
- GRB 230328B: CAHA 2.2m/CAFOS detection
- IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230328B: 3.6m DOT multiband optical observation
- Fermi trigger No 701883729: Global MASTER-Net observations report
- GRB 230330B: Fermi GBM Final Localization
- Konus-Wind detection of GRB 230328B
- GRB 230328B: GRBAlpha detection
- GRB 230330A: Fermi GBM Final Real-time Localization
- GRB 230328B: Swift-BAT refined analysis
- GRB 230328B: Nanshan/NEXT 2nd optical observation
- GRB 230328B NUTTelA-TAO / BSTI Early Measurements
- GRB 230328B: Liverpool Telescope afterglow detection
- GRB 230328B: OHP/T120 optical observations