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.
Advanced Search Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
3821 results found.
- Fermi GRB 231103A: Global MASTER-Net observations report
- GRB 231104A: Fermi-LAT detection
- LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
- IceCube Alert 231103.39: Global MASTER-Net observations report
- Fermi trigger No 720498201: Global MASTER-Net observations report
- GRB 231024A: AKO Optical Counterpart Candidate
- Fermi GRB 231030A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231029k: Global MASTER-Net observations report
- Fermi trigger No 720224759: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
- IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
- LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
- Fermi GRB 231019A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
- GRB 230827B: 10.4m GTC spectroscopic redshift
- LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
- IPN triangulation of GRB 230919A (short)
- transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
- LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
- IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230911A: Swift-XRT afterglow detection
- Fermi trigger No 716449174: Global MASTER-Net observations report
- IceCube Alert 230914.22: Global MASTER-Net observations report
- GRB 230911A: GOTO optical counterpart candidate
- GRB 230906A: Chandra detection of the X-ray afterglow
- GRB 230903A: VLT/X-shooter optical observations
- GRB 230904C: Fermi GBM Final Localization
- Fermi GRB 230903A: Global MASTER-Net observations report
- GRB 230904B is not a GRB
- GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
- GRB 230828A: AstroSat CZTI detection
- GRB 230828A: GRBAlpha detection
- Swift Trigger 1188089 is not a GRB
- Fermi GRB 230827A: Global MASTER-Net observations report
- GRB 230824A: AKO Photometric Follow-up Observations
- Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
- GRB 230818B: VZLUSAT-2 detection
- LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
- GRB 230818A: SAO RAS Zeiss-1000 observations
- Fermi GRB 230818A: Global MASTER-Net observations report
- GRB 230818A: Swift detection of a burst
- Fermi GRB 230817A: Global MASTER-Net observations report
- GRB 230816A: TShAO and Assy optical observations
- GRB 230816A: SAO RAS optical observations
- IPN triangulation of GRB 230815B
- GRB 230812B: Fermi-LAT detection
- GRB 230812B: Fermi GBM Observation of a very bright burst
- LAT GRB230812.79: Global MASTER-Net observations report
- GRB 230812B: Fermi GBM detection of an extremely bright GRB
- LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
- IceCube-230724A: JCMT/SCUBA-2 submm observations
- LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
- IceCube Alert 230724.08: Global MASTER-Net observations report
- GRB 230724A: Fermi GBM Final Real-time Localization
- Fermi trigger No 711805358: Global MASTER-Net observations report
- Fermi GRB 230723A: Global MASTER-Net observations report
- GRB 230707A: Fermi GBM Detection
- Fermi GRB 230707A: Global MASTER-Net observations report
- Fermi trigger No 710117592: Global MASTER-Net observations report
- GRB 230628E: ATCA rapid radio follow-up
- AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
- GRB 230628E - VLT spectroscopic observations
- Fermi GRB 230628C: Global MASTER-Net observations report
- Fermi GRB 230628D: Global MASTER-Net observations report
- GRB 230628E: Swift detection of a burst
- GRB 230626A: GRBAlpha detection
- GRB 230623A: MAXI/GSC detection
- LIGO/Virgo S230621ad: Global MASTER-Net observations report
- Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
- LIGO/Virgo S230620ad: Global MASTER-Net observations report
- AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
- LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
- ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
- GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
- LIGO/Virgo S230619i: Global MASTER-Net observations report
- LIGO/Virgo S230618aq: Global MASTER-Net observations report
- LIGO/Virgo S230618y: Global MASTER-Net observations report
- LIGO/Virgo S230618s: Global MASTER-Net observations report
- LIGO/Virgo S230616aa: Global MASTER-Net observations report
- LIGO/Virgo S230615ak: Global MASTER-Net observations report
- LIGO/Virgo S230618k: Global MASTER-Net observations report
- LIGO/Virgo S230617bc: Global MASTER-Net observations report
- LIGO/Virgo S230617aq: Global MASTER-Net observations report
- LIGO/Virgo S230617aj: Global MASTER-Net observations report
- GRB 230616A: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S230529ay: Upper limits from a two-week IceCube neutrino search
- LIGO/Virgo S230615be: Global MASTER-Net observations report
- LIGO/Virgo S230608aw: Global MASTER-Net observations report
- LIGO/Virgo S230609a: Global MASTER-Net observations report
- LIGO/Virgo S230608ah: Global MASTER-Net observations report
- GRB 230606A: Enhanced Swift-XRT position