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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
32083 results found.
- GRB 250430A / EP250430a: J-band upper limits with WINTER
- GRB 250430A: NUTTelA-TAO Early Measurements
- EP250427a / GRB 250427A: OHP/T193 photometric observations: third visit
- GRB 250430A: DDOTI Optical Observations
- GRB 250430A: Leavitt Observatory optical upper limit
- GRB 250430A: Bassano Bresciano Observatory upper limit
- GRB 250430A : MITSuME Akeno optical upper limits
- GRB 250430A / EP250430a: VLT/X-shooter spectroscopic redshift z = 0.767
- EP250430a/GRB 250430A: Einstein Probe WXT detection of the X-ray prompt emission
- GRB 250424A: CALET Gamma-Ray Burst Monitor detection
- GRB 250430A: AKO Optical Afterglow Detection
- GRB 250430A: Kanata optical upper limit
- EP 250427A: Optical counterpart detection by LCO.
- GRB 250430A: Swift detection of a burst with optical counterpart
- EP250427a / GRB 250427A: OHP/T193 continued photometric observations
- EP250428b: SAO RAS optical upper limit
- GRB 250427A: Swift/UVOT Detection
- EP250427a / GRB 250427A: OHP/T193 photometric observations
- EP250427a: EP-FXT follow-up observations
- EP250427a/GRB 250427A: FTW optical and NIR observations of the counterpart
- GRB250427A/EP250427a GIT optical afterglow detection:
- GRB 250427A: Swift-XRT refined Analysis
- EP250427a / GRB 250427A: LCO optical counterpart detection
- EP250427a / GRB 250427A: VLT/X-shooter redshift confirmation z = 1.520
- EP250427A/GRB250427A: Keck/LRIS redshift
- GRB 250424A: LCO optical observation
- GRB 250427A/ EP250427a: Fermi-GBM Sub-Threshold Detection
- GRB 250424A: Swift-BAT refined analysis
- GRB 250424A: SVOM/GRM observation of a long burst
- GRB 250424A: PRIME near-infrared detection
- GRB 250424A: WINTER J-band detection
- GRB 250424A: EIRSAT-1 GMOD Detection
- GRB 250424A: SVOM/VT optical observation
- GRB 250419A: Mondy Optical Observations
- GRB 250424A: Swift/UVOT Detection
- Konus-Wind detection of GRB 250424A
- GRB 250424A: Skynet Optical Observations
- GRB 250424A: Kilonova-Catcher optical afterglow detection
- GRB 250419a: Continued Liverpool Telescope observations
- GRB 250419A: Liverpool Telescope optical upper limit
- GRB 250407A: GRBAlpha detection
- GRB 250404A / EP250404a: GRBAlpha detection
- GRB 250330B: GRBAlpha detection
- GRB 250419A: SVOM/ECLAIRs refined analysis
- GRB 250424A: Swift-XRT refined Analysis
- GRB 250424A: Enhanced Swift-XRT position
- GRB 250424A: AstroSat CZTI detection of a bright long burst
- GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
- GRB 250424A: BlackGEM optical afterglow detection
- GRB 250424A: VLT/X-shooter spectroscopic redshift z = 0.310
- GRB 250424A: likely host galaxy
- GRB 250424A: DDOTI Afterglow Detection
- GRB 250424A: REM optical/NIR afterglow detection
- GRB 250424A: Swift detection of a burst with an optical counterpart
- EP250421a: Nickel optical upper limit
- EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
- EP250421a: Upper limits from Fermi-GBM Observations
- SVOM/sb25042207: GOTO optical upper limits
- GRB 250421A: AstroSat CZTI detection
- GRB250419A: VLA radio detection
- GRB 250419A: Mephisto Multi-band Optical Detection
- GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
- GRB 250419A: Optical Observations via Virtual Telescope Project
- GRB 250419A: Mondy Continued Optical Observations
- Fermi GRB 250421A: Global MASTER-Net observations report
- GRB 250421B: AstroSat CZTI detection of a bright long burst
- GRB 250421A: Fermi GBM Final Real-time Localization
- GRB 250419A: Liverpool Telescope observations
- GRB 250419A: LCO optical observation
- GRB 250419A: JinShan optical observations
- GRB 250419A: SVOM/VT optical continuous observations
- GRB 250419A: SVOM/C-GFT optical observations
- GRB 250419A: Swift/UVOT Follow up
- GRB 250416C / EP250416a: SVOM/GRM observation of a burst
- GRB 250419A: LCO optical afterglow multi-band observations
- GRB 250419A: Mondy and AbAO Optical Observations
- GRB 250419A: Liverpool Telescope observations
- GRB 250419A: AKO Optical Afterglow Detection
- GRB 250419A: MASTER optical afterglow observation
- GRB 250407A: rest-frame energetics from Konus-Wind observation
- GRB 250419A: Swift-XRT localisation
- GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
- GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
- GRB 250419A: Swift-XRT refined Analysis
- GRB 250419A: GOTO optical counterpart detection
- GRB 250419A: KAIT optical afterglow observations
- GRB 250419A: SVOM/VT optical bright counterpart confirmation
- GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
- GRB 250419A: SVOM detection of a soft burst
- Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
- Konus-Wind detection of GRB 250403A
- GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
- SVOM/sb25041603 is not a GRB
- Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
- Fermi Gamma-ray Burst Monitor trigger 766511207/250416657 is not a GRB
- GRB 250416B: Fermi GBM Final Real-time Localization
- GRB 250416A: Fermi GBM Final Real-time Localization
- Fermi Gamma-ray Burst Monitor trigger 766474855/250416237 is not a GRB
- GRB 250413A: AstroSat CZTI detection
- EP250304a: ATCA radio observations