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"24361 results found.
- Fermi GRB 260120C: Global MASTER-Net observations report
- GRB 260120B: Swift-BAT refined analysis
- GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
- GRB 260120B: Fermi GBM Observation
- EP260105a: GTC/HiPERCAM optical observations
- GRB 260120B: COLIBRÍ optical upper limits
- SVOM GRB260121.06: Global MASTER-Net observations report
- GRB 260120B: SVOM/C-GFT optical counterpart detection
- GRB 260120C: Fermi GBM Final Real-time Localization
- GRB 260120B: Swift detection of a burst
- Swift GRB260120B: Global MASTER-Net observations report
- GRB 260120B: Fermi GBM Final Real-time Localization
- Fermi trigger No 790601190: Global MASTER-Net observations report
- Fermi trigger No 790570272: Global MASTER-Net observations report
- EP260119a: Liverpool Telescope optical follow-up observations
- EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
- EP260119a: KAIT optical observations
- GRB 260120A: Fermi GBM Final Real-time Localization
- EP260119a: SVOM/VT optical observation
- EP260119a: update of EP-FXT follow-up observation
- SVOM GRB260119.92: Global MASTER-Net observations report
- SVOM GRB260119.92: Global MASTER-Net observations report
- SVOM GRB260119.90: Global MASTER-Net observations report
- GRB 251208D: SVOM/ECLAIRs refined analysis
- GRB 251208D: SVOM/ECLAIRs refined analysis
- GRB 260117A: Swift-XRT afterglow detection
- EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
- EP260119a: Global MASTER-Net observations report
- GRB 260110A: SVOM detection of a burst through offline search
- Swift GRB260118.48: Global MASTER-Net observations report
- SVOM GRB260117.82: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-260115A
- GRB 260117A: SVOM/VT optical candidate
- GRB 260117A: SVOM/C-GFT upper limit
- GRB 260117A: Swift-XRT observations
- GRB 260117A: SVOM detection of a long faint burst
- Swift triggered on the HMXB 1A 1118-61
- GRB 260115A: GECAM-B observation
- FRB 20251229A: COLIBRÍ further inspection of the updated localization
- FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
- EP260116A: 1.3m DFOT optical upper limit
- GRB 260114A: VLT/MUSE spectroscopic observations
- IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
- EP260116a: Global MASTER-Net observations report
- EP260116a: Xinglong optical upper limit
- EP260116a: Einstein Probe detection of an X-ray transient
- GRB 260114A: VLT/HAWK-I further near-infrared upper limits
- IceCube Alert 260115.73: Global MASTER-Net observations report
- IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
- IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
- Fermi GRB 260115A: Global MASTER-Net observations report
- GRB 260115A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 260114A
- GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
- GRB 260114A : MITSuME Akeno optical upper limits
- GRB 260114A: TNG NIR upper limit
- GRB 260114A: NOT optical observations
- Konus-Wind detection of GRB 251230A / EP251230a
- GRB 260114A: SVOM/GRM observation of a short burst
- Swift GRB 260114A: Global MASTER-Net observations report
- GRB 260114A: GECAM-B observation of a short burst
- GRB 260114A: Fermi GBM observation
- Fermi-LAT Gamma-ray Observations of IceCube-260111A
- GRB 260114A: Swift detection of a short burst
- GRB 260114A: Fermi GBM Final Real-time Localization
- IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
- Swift GRB260113.43: Global MASTER-Net observations report
- EP260110a: NOT and GTC Optical and Near-Infrared Observations
- EP260110a: TRT optical upper limits
- Konus-Wind detection of GRB 260101A
- GRB 260111A: Fermi GBM Observation
- The EP-WXT trigger 01709251266 is likely a flaring star
- Swift Trigger 1434591 is not a GRB
- GRB 260111A: GOTO optical upper limits
- GRB 260112B: Fermi GBM Final Real-time Localization
- GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 260112A: Fermi GBM Final Real-time Localization
- EP260110a: SVOM/VT optical upper limits
- IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube Alert 260111A: Global MASTER-Net observations report
- EP260110a: Global MASTER-Net observations report
- Fermi GRB 260111A: Global MASTER-Net observations report
- GRB 260111A: Fermi GBM Final Real-time Localization
- Swift trigger 1436759 is not an astrophysical event
- EP260110a: KAIT optical upper limit
- EP260110a: refined analysis of the EP-WXT and EP-FXT observations
- EP 260110a: COLIBRÍ optical observations
- EP260110a: SVOM/C-GFT upper limit
- EP260110a: BOOTES-5/JGU optical upper limit
- GRB 260109C: LCO optical upper limits
- EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
- GRB 260109B: Fermi GBM Final Real-time Localization
- GRB 260102A: Swift-XRT afterglow detection
- GRB 260109A: Fermi GBM Final Real-time Localization
- GRB 260104A: Swift-BAT refined analysis
- GRB 260101A: Swift-BAT refined analysis
- Swift GRB 251230A: Global MASTER-Net OT detection
- Fermi GRB 260107A: Global MASTER-Net observations report
- GRB 260107A: Fermi GBM Final Real-time Localization