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"4066 results found.
- LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
- LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
- LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
- LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
- LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
- LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
- LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
- LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
- LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
- LIGO/Virgo/KAGRA S251103f: Updated Sky localization
- LIGO/Virgo/KAGRA S251031dw: Candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
- GRB 251103A: NOT optical afterglow candidate (duplicate submission)
- LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
- IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
- GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
- LIGO/Virgo/KAGRA S251026bn: Updated Sky localization
- LIGO/Virgo/KAGRA S251026bn: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251021u: Updated Sky localization
- LIGO/Virgo/KAGRA S251021u: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251018bi: Updated Sky localization
- IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S251018bi: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251017di: Retraction of GW compact binary merger candidate
- GRB 251013C: Leavitt Observatory optical photometry
- LIGO/Virgo/KAGRA S251014cn: Updated Sky localization
- Upper limits from a search for additional neutrino events in IceCube
- GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
- LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
- LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
- GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
- LIGO/Virgo/KAGRA S251013x: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251003at: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250830bp: SOAR spectroscopy of two DESGW candidates
- LIGO/Virgo/KAGRA S250818k: further MeerKAT monitoring
- LIGO/Virgo/KAGRA S250929c: Updated Sky localization
- LIGO/Virgo/KAGRA S250929c: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250927cy: Updated Sky localization
- LIGO/Virgo/KAGRA S250927ck: Updated Sky localization
- LIGO/Virgo/KAGRA S250927cy: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250927ck: Identification of a GW compact binary merger candidate
- IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
- LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
- LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
- LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
- LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
- LIGO/Virgo/KAGRA S250912f: Updated Sky localization
- LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S250908y: Updated Sky localization
- LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
- LIGO/Virgo/KAGRA S250910b: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
- IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
- LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
- LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
- LIGO/Virgo/KAGRA S250904br: Updated Sky localization
- LIGO/Virgo/KAGRA S250904ae: Updated Sky localization
- LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
- LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data
- IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
- LIGO/Virgo/KAGRA S250901cb: Updated Sky localization
- LIGO/Virgo/KAGRA S250830bp: DECam GW-MMADS candidates
- LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 1 Candidates
- LIGO/Virgo/KAGRA S250901cb: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250830m: Updated Sky localization
- LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
- LIGO/Virgo/KAGRA S250830bp: NED Galaxies in the 4-Update Localization Volume
- LIGO/Virgo/KAGRA S250830bp: Updated Sky localization, EM Bright Classification, and Source Classification
- LIGO/Virgo/KAGRA S250830bp: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250830m: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
- LIGO/Virgo/KAGRA S250818k: MeerKAT detection of an increase in radio flux from AT2025ulz
- LIGO/Virgo/KAGRA S250827fo: Updated Sky localization
- LIGO/Virgo/KAGRA S250818k: uGMRT 1.3 GHz observations of AT2025ulz
- LIGO/Virgo/KAGRA S250827fo: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250827l: Updated Sky localization
- LIGO/Virgo/KAGRA S250827l: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250818k: SAO RAS BTA z-band observations of AT2025ulz