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"15373 results found.
- GRB 251005C: Fermi GBM Observation
- GRB 251002A: Insight-HXMT detection
- GRB 251002A: Insight-HXMT detection
- GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
- GRB 251003A: Swift/UVOT Upper Limits
- GRB 251002A: Swift/UVOT detection
- GRB 251001A: AstroSat CZTI detection
- GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
- GRB 251002A: Fermi GBM Observation
- GRB 251001C: SVOM/GRM observation
- GRB 251003A: Kilonova-Catcher optical afterglow detection
- GRB 251002A: Kilonova-Catcher optical afterglow detection
- GRB 251002A: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 251002A: OHP/T193 MISTRAL optical afterglow detection
- GRB 251002A: EP-FXT counterpart detection
- GRB 251003A: COLIBRÍ optical detection of the fading afterglow
- GRB 251002A: BOOTES-6 early optical detection
- GRB 251002A: FRAM-ORM afterglow detection
- GRB 251002A: LCO optical observation
- GRB 251002A: SVOM detection of a burst
- GRB 251001A: SVOM/GRM observation
- GRB 251001A: Insight-HXMT detection
- GRB 251001B: COLIBRÍ optical observations
- GRB 251001B: GTC/OSIRIS+ spectroscopic redshift z = 2.162
- GRB 251001B: Fermi GBM Observation
- GRB 250930A: SVOM/GRM observation
- GRB 251001A: Fermi GBM Detection
- GRB 250910A / EP250910a: VLT limits on the possible associated supernova
- LIGO/Virgo/KAGRA S250830bp: SOAR spectroscopy of two DESGW candidates
- LIGO/Virgo/KAGRA S250818k: further MeerKAT monitoring
- Fermi-LAT Gamma-ray Observations of IceCube-250926A
- GRB 250924A: SVOM/GRM observation
- IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
- GRB 250926A: Insight-HXMT detection
- GRB 250920C: ULL-ASTRO-MASTER early detection of the optical afterglow with LCO 40-cm telescope at Siding Spring Observatory
- GRB 250926A: AstroSat CZTI detection
- GRB 250925A: Swift/UVOT Upper Limits
- IceCube-250926A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 250925A/EP250925a: EP-WXT detection
- GRB 250926A: DDOTI Optical Observations and Spatial Coincidence with the Orion Nebula
- GRB 250925A : MITSuME Akeno optical upper limits
- GRB 250925A: JinShan optical observations
- GRB 250925A: 1.5m OSN optical detection and redshift with the 10.4m GTC/OSIRIS+
- GRB 250925A: COLIBRÍ optical photometry of the afterglow
- GRB 250922A: SVOM/GRM observation
- GRB 250924A: 1.6m Mephisto optical upper limits
- GRB 250924A: AstroSat CZTI detection
- GRB 250914A: AstroSat CZTI detection
- GRB 250920B: AstroSat CZTI detection
- GRB 250924A: KAIT optical observations
- GRB 250924A: Kilonova-Catcher optical afterglow detection
- GRB 250920C: Kilonova-Catcher optical afterglow detection
- GRB 250922B: SVOM/GRM observation
- GRB 250924A: COLIBRÍ optical observations
- Konus-Wind detection of GRB 250920C
- EP250911a: e-MERLIN radio observations
- GRB 250920C: SALT redshift confirmation
- GRB 250920C: COLIBRÍ optical observations
- GRB 250922C: AstroSat CZTI detection of a short burst
- GRB 250920C: PRIME near-infrared detection
- Konus-Wind detection of GRB 250920B
- Konus-Wind detection of GRB 250920A
- Konus-Wind detection of GRB 250911A
- GRB 250920C: SVOM/GRM observation
- GRB 250920C: GTC/OSIRIS+ spectroscopic redshift z = 1.40
- GRB 250920C: GROWTH-India Telescope optical observations
- GRB 250920C: Optical counterpart detection by LCO
- GRB 250920A: SVOM/GRM observation
- GRB 250920B: SVOM/C-GFT optical observations
- Konus-Wind detection of GRB 250919A
- LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
- GRB 250919A / EP250919a: Insight-HXMT detection
- GRB 250920A: AstroSat CZTI detection
- GRB 250918A: SVOM/GRM observation
- GRB 250919A/EP250919A: Swift/UVOT afterglow detection
- GRB 250919A: Fermi-LAT detection
- GRB 250919A: SVOM/GRM observation of a very bright GRB
- GRB 250916A: Fermi GBM Observation
- GRB 250917B: VLT/HAWK-I near-infrared observations
- GRB 250912A: SVOM/ECLAIRs refined analysis
- GRB 250916A : GIT optical observations
- LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
- GRB 250916A: Glowbug gamma-ray detection
- GRB 250916A: Swift ToO observations
- GRB 250917B: Fermi GBM Observation
- GRB 250916A: AstroSat CZTI detection of a bright long burst
- GRB 250910A: SVOM/ECLAIRs refined analysis
- LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
- SVOM/sb25091517: Confirmation of a stellar flare by SVOM/VT
- SVOM/sb25091517: FRAM-ORM stellar flare - transient observation
- SVOM/sb25091517: SVOM detection of an X-ray transient
- GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 250912A: Swift-XRT observations
- GRB250912A: VLT/HAWK-I follow-up observations
- GRB 250912A: Fermi GBM Observation
- GRB 250911A: Insight-HXMT detection
- GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
- GRB 250912A: SVOM detection of a burst
- IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
- EP250911a: Upper limit from Fermi-GBM Observations