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"27166 results found.
- GRB 250806A: EP-FXT observation
- EP#01709198415/EP250806a: Swift-XRT observations
- EP250806a: Global MASTER-Net observations report
- EP250802a: EP-FXT follow-up observation
- EP250806a: refined analysis of the EP-WXT and EP-FXT observations
- EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
- EP250806a: SVOM /VT optical candidate
- GRB 250806A: J-band upper limit from WINTER
- GRB 250805A: Swift-BAT refined analysis
- GRB 250806A: SVOM/VT refined analysis
- GRB 250806A: Swift-XRT counterpart detection
- EP250806a: COLIBRÍ optical upper limit
- GRB 250806A: Kilonova-Catcher optical upper limits
- EP250806a: Einstein Probe detection of an X-ray transient
- GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 250806A: SVOM/VT optical upper limit
- GRB 250806A: SVOM detection of a soft burst
- GRB 250805A: SVOM/VT optical counterpart
- GRB 250805A: Swift-XRT refined Analysis
- GRB 250804C: AstroSat CZTI detection of a long burst
- GRB 250805A: TRT optical upper limits
- GRB 250805A: Swift-XRT observations
- GRB 250805A: Swift detection of a burst
- Swift GRB250805.26: Global MASTER-Net observations report
- Fermi trigger No 776041355: Global MASTER-Net observations report
- GRB 250804B: SVOM/GRM observation of a short burst
- GRB 250804A: Fermi GBM Final Localization
- EP250730a: SVOM/VT optical upper limit
- Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
- EP250802a: Liverpool Telescope optical upper limits
- EP250802a: Global MASTER-Net observations report
- EP250802a: GROWTH-India Telescope optical upper limit
- EP250802a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709198251 is likely a flaring star
- The EP-WXT trigger 01709198202 is likely a flaring star
- LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
- LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
- EP250711a: CrAO and Assy optical observations
- EP250730a: Global MASTER-Net observations report
- EP250730a: COLIBRÍ optical upper limit
- GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
- EP250730a: Einstein Probe detection of an X-ray transient
- LIGO/Virgo/KAGRA S250727dc: Swift-UVOT follow up of AT 2025smm
- LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
- GRB 250727A: EP-FXT follow-up observation
- GRB 250727A: SVOM/ECLAIRs refined analysis
- EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
- GRB 250728A: COLIBRÍ optical upper limit
- GRB 250728A: Fermi GBM Observation
- Fermi trigger No 775387550: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
- GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 250727A: EP-FXT counterpart detection
- GRB250727A: SVOM/VT optical upper limit
- GRB 250727A: Swift-XRT observations
- GRB 250727A: SVOM detection of a burst
- The EP-WXT trigger 01709195487 is likely a flaring star
- Swift detection of the Soft Gamma Repeater PSR J1647-4552
- GRB 250725A: Swift-XRT refined Analysis
- GRB 250725A: Fermi GBM Observation
- GRB 250725A: Swift-BAT refined analysis
- GRB 250725A: SVOM/GRM observation
- GRB 250725A: Swift/UVOT Upper Limits
- GRB 250725A: Fermi-LAT detection
- GRB 250725A: SVOM/VT optical candidate
- GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
- GRB 250725A: Swift detection of a burst
- Swift GRB 250725A: Global MASTER-Net OT detection
- GRB 250725A: Fermi GBM Final Real-time Localization
- Fermi GRB 250725A: Global MASTER-Net observations report
- Swift GRB 250725A: Global MASTER-Net observations report
- SVOM J195836+32283/sb25072103: Second VT observation
- SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
- GRB 250723B: Fermi GBM Final Real-time Localization
- GRB 250721A: Fermi GBM Observation
- GRB 250723A: Fermi GBM Final Real-time Localization
- SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
- SVOM J195836+32283/sb25072103: NIR observations with WINTER
- Swift-BAT trigger 1334535 is not a GRB
- GRB 250722A: Fermi GBM Final Real-time Localization
- GRB 250713A : SVOM/ECLAIRs refined analysis
- GRB 250717B: SVOM/GRM observation
- The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
- GRB 250721A: Fermi GBM Final Localization
- GRB 250720B: Fermi GBM Final Localization Correction
- GRB 250720A: Fermi GBM Final Localization
- Fermi trigger No 774730635: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
- Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
- EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
- GRB 250717B: COLIBRÍ optical upper limit
- LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
- GRB 250718B: Fermi GBM Final Localization Correction
- GRB 250718B: Fermi GBM Final Real-time Localization
- Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
- Swift Trigger 1334535: a possible GRB 250718A
- Swift GRB250718.01: Global MASTER-Net observations report