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"38199 results found.
- GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
- GRB 251023B / EP251023b: Mondy optical upper limit
- GRB 251017A: INASAN-Kislovodsk optical observations
- GRB 251026A: Mondy optical upper limit
- GRB 251025B: Mondy optical observations
- GRB 251025B: Kilonova-Catcher optical afterglow detection
- Konus-Wind detection of GRB 251016A (short/hard)
- GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
- GRB 251027A: SVOM detection of a faint burst
- GRB 251026B: Tentative GOTO optical counterpart candidate
- GRB 251025C: AstroSat CZTI detection
- EP251023a: Mondy optical observations
- GRB 251025C: CALET Gamma-Ray Burst Monitor detection
- GRB 251025B: MAO/AZT-22 optical observations
- Fermi GRB 251026B: Global MASTER-Net observations report
- Fermi GRB 251025C: Global MASTER-Net observations report
- GRB 251026A: Swift-XRT observations
- GRB 251025B: OHP/T193 optical detection
- GRB 251025B: J-band detection with WINTER
- GRB 251026A: SVOM/C-GFT upper limit
- GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 251026B: Fermi GBM Final Localization
- GRB 251026A: SVOM detection of a long burst
- GRB 251025B: SVOM/VT optical bump
- GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
- GRB 251023A: SVOM/GRM observation
- GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
- GRB 251025C: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 251016B
- GRB 251025B: GROWTH-India Telescope optical observations
- GRB 251024A: Swift/UVOT Upper Limits
- GRB 251025B: Swift-XRT afterglow detection
- GRB 251024A: Swift-BAT refined analysis
- IceCube Alert 251025.57: Global MASTER-Net observations report
- GRB 251024A: Swift-XRT refined Analysis
- GRB 251025A (sb25102501): stellar flare confirmed
- GRB 251025B: SVOM/VT optical observations with VHF data
- GRB 251025B: MASTER OT detection
- GRB 251025B: SVOM/C-GFT optical counterpart detection
- GRB 251025B: SVOM detection of a burst
- GRB 251025A (sb25102501): Likely a stellar flare by SVOM/VT
- GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 251025A: SVOM/VT VHF optical upper limit
- GRB 251025A: SVOM detection of a faint burst
- GRB 251003A: VLA Detection
- GRB 251024A: Enhanced Swift-XRT position
- GRB 251023C: Glowbug gamma-ray detection
- GRB 251024A: LCOGT Optical Afterglow Detection
- GRB 251022A: KAIT optical observations
- GRB 251024A: Swift detection of a burst
- Swift GRB 251024A: Global MASTER-Net observations report
- GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
- GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
- GRB 251023B: OHP/T193 optical observations
- EP251023a: OHP/T193 optical observations
- GRB 251023C: AstroSat CZTI detection
- EP251023b/GRB 251023B: JinShan optical observation
- GRB 251022A: Swift-XRT detection of GOTO25iym
- EP251023b: Global MASTER-Net observations report
- EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
- GRB 251023C: CALET Gamma-Ray Burst Monitor detection
- GRB 251022A: GROWTH-India Telescope optical observations
- GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
- GRB 251022A: Fermi GBM Observation
- GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
- GRB 251023A: Glowbug gamma-ray detection
- GRB 251023B: Glowbug gamma-ray detection
- EP251023a: Global MASTER-Net observations report
- GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
- IPN triangulation of GRB 251016B
- GRB 251023B: CALET Gamma-Ray Burst Monitor detection
- EP#01709247298: Swift-XRT counterpart detection
- GRB 251013C: further SAO RAS optical observations
- GRB 251022A: COLIBRÍ optical observations
- GRB 251013C: ISON-Castelgrande observatory optical observations
- GRB 251022A: MASTER OT detection
- GRB 251022A: DDOTI Optical Detection
- EP251021b/GRB 251021A: SVOM/VT optical candidate
- GRB 251023B / MAXI J0451+122: MAXI/GSC detection
- Fermi GRB 251023A: Global MASTER-Net observations report
- EP251023a: GSP Optical Counterpart Detection
- GRB 251022A: GOTO optical counterpart detection
- GRB 251023A: Fermi GBM Final Localization Correction
- GRB 251022A: Fermi-LAT detection
- GRB 251016B: Fermi GBM Detection
- GRB 251022A: Tiled Swift observations
- LAT GRB251022A: Global MASTER-Net observations report
- GRB 251022A: Fermi GBM Final Real-time Localization
- GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
- GRB 250911A: MAXI/GSC detection
- GRB 251016A: SVOM/ECLAIRs refined analysis
- GRB 251017A : RAPAS follow-up observations
- GRB 251017A: COLIBRÍ optical observations of a late plateau
- GRB 251017A: Swift-BAT refined analysis
- GRB 251016A: Fermi GBM Observation
- GRB 251018A: Fermi GBM Observation
- GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
- GRB 251018A: Swift-XRT refined Analysis
- GRB 251018A: Enhanced Swift-XRT position
- Fermi trigger No 782500909: Global MASTER-Net observations report