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.
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"28115 results found.
- Corrected Swift-XRT Refined Analysis of GRB 250809A
- GRB 250809A: Swift-XRT refined Analysis
- GRB 250809A: LCOGT Optical Upper Limits
- GRB 250702B: Chandra X-ray Detection
- GRB 250808A: VLT X-shooter candidate counterpart
- GRB 250809A: Prompt enhanced Swift-XRT position
- GRB 250809A: Swift detection of a gamma ray burst
- GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 250808A: Swift-XRT candidate counterpart detection
- GRB 250807A: SVOM/VT optical continued observation
- GRB 250808A: SVOM detection of a long burst
- GRB 250808A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 250807A
- GRB 250807B: Swift/UVOT Detection
- GRB 250807B: Kilonova-Catcher optical afterglow detection
- GRB 250807A: Swift/UVOT Detection
- GRB 250807A: Swift-XRT refined Analysis
- GRB 250806A: SVOM/MXT refined analysis
- GRB 250806A: SVOM/ECLAIRs refined analysis
- GRB 250804B: Insight-HXMT detection
- GRB 250807A: AstroSat CZTI detection of bright long burst
- GRB 250807B: Swift-XRT refined Analysis
- GRB 250806A: NOT z-band upper limit and host galaxy candidate
- GRB 250807B: NTT optical observations
- EP250807a: EP-WXT detection of a fast X-ray transient
- GRB 250807A: SVOM/VT optical observation
- GRB 250807B: Enhanced Swift-XRT position
- GRB 250807A: Enhanced Swift-XRT position
- GRB 250807B: Swift detection of a burst with an optical counterpart.
- GRB 250805A: Kilonova-Catcher optical upper limits
- GRB 250805A: Swift/UVOT Upper Limits
- GRB 250806A: Swift/UVOT U-band detection
- GRB 250807A: Swift detection of a burst with an optical counterpart
- GRB 250806A: EP-FXT observation
- EP#01709198415/EP250806a: Swift-XRT observations
- EP250802a: EP-FXT follow-up observation
- EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
- GRB 250806A: J-band upper limit from WINTER
- GRB 250806A: KAIT optical upper limit
- GRB 250806A: SVOM/VT refined analysis
- GRB 250806A: Swift-XRT counterpart detection
- EP250806a: Einstein Probe detection of an X-ray transient
- GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 250806A: SVOM detection of a soft burst
- GRB 250805A: SVOM/VT optical counterpart
- GRB 250805A: ESO/VLT observations
- GRB 250805A: Swift-XRT refined Analysis
- GRB 250804B: Swift-XRT observations
- GRB 250805A: Enhanced Swift-XRT position
- GRB 250804C: AstroSat CZTI detection of a long burst
- GRB 250805A: TRT optical upper limits
- IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 250805A: Swift-XRT observations
- GRB 250805A: Swift detection of a burst
- GRB 250804B: Tiled Swift observations
- GRB 250804A: Fermi GBM Final Localization
- EP250802a: additional Liverpool Telescope upper limits
- EP250802a: GROWTH-India Telescope optical upper limit
- EP250802a: Einstein Probe detection of an X-ray transient
- LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
- LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
- GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
- EP250730a: Einstein Probe detection of an X-ray transient
- LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
- GRB 250725A: AstroSat CZTI detection
- GRB 250727A: EP-FXT follow-up observation
- GRB 250725A: PRIME near-infrared observations
- LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
- GRB: Clarification on Gamma-Ray Burst Naming Convention
- GRB 250728A: Swift-XRT observations
- EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
- GRB 250728A: COLIBRÍ optical upper limit
- LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
- GRB 250728A: Swift ToO observations
- GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 250727A: AST3-2 Upper limit
- GRB 250727A: EP-FXT counterpart detection
- GRB250727A: SVOM/VT optical upper limit
- GRB 250727A: Swift-XRT observations
- GRB 250727A: SVOM detection of a burst
- Swift detection of the Soft Gamma Repeater PSR J1647-4552
- GRB 250725A: Swift-XRT refined Analysis
- GRB 250725A: Fermi GBM Observation
- Konus-Wind detection of GRB 250725A
- GRB 250725A: Swift/UVOT Upper Limits
- GRB 250725A: Fermi-LAT detection
- GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
- GRB 250725A: BOOTES-7 early optical detection
- GRB 250725A: SVOM/VT optical candidate
- GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
- GRB 250725A: Enhanced Swift-XRT position
- GRB 250725A: Swift detection of a burst
- Swift GRB 250725A: Global MASTER-Net OT detection
- GRB 250725A: Fermi GBM Final Real-time Localization
- EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
- EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
- SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
- GRB 250723B: Fermi GBM Final Real-time Localization
- GRB 250723A: Fermi GBM Final Real-time Localization
- SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits