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"
2722 results found.
- GRB 240115B: Fermi GBM Final Real-time Localization
- Fermi trigger No 726774492: Global MASTER-Net observations report
- Fermi GRB 240112B: Global MASTER-Net observations report
- IceCube-240105A: Three candidates from the Zwicky Transient Facility
- GRB 240107A: MAXI/GSC detection
- Fermi trigger No 726194053: Global MASTER-Net observations report
- GRB 231230A: GOTO optical upper limits
- Fermi trigger No 725592555: Global MASTER-Net observations report
- LAT GRB231222.31: Global MASTER-Net observations report
- GRID detection of GRB 231215A
- Fermi trigger No 724781422: Global MASTER-Net observations report
- GRB 231215A: GRBAlpha detection
- Swift GRB231216.77: Global MASTER-Net observations report
- Konus-Wind detection of GRB 231215A
- GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
- GRB 231215A: Fermi GBM observation
- GRB 231215A: CALET Gamma-Ray Burst Monitor detection
- GRB 231215A: AGILE detection
- GRB 231215A: AstroSat CZTI detection
- GRB 231215B: Fermi GBM Final Real-time Localization
- GRB 231215A: Swift detection of a burst
- Fermi trigger No 724278269: Global MASTER-Net observations report
- IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
- IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-231202A: No candidates from the Zwicky Transient Facility
- IPN triangulation of GRB 231129C
- GRB 231208A: AstroSat CZTI detection of a faint burst
- GRB 231205B: Swift detection of a burst
- Fermi trigger No 723435916: Global MASTER-Net observations report
- Fermi trigger No 723326169: Global MASTER-Net observations report
- Fermi trigger No 723412808: Global MASTER-Net observations report
- GRB 231203A: Fermi GBM Final Real-time Localization
- GRB 231129A : MITSuME Akeno optical upper limits
- GRB 231129C: MAXI/GSC detection
- GRB 231117A: MeerKAT 1.3GHz detection
- GRB 231125A: GRBAlpha detection
- GRB 231125A: CALET Gamma-Ray Burst Monitor detection
- GRB 231125A (short): Glowbug gamma-ray detection
- GRB 231125A: AstroSat CZTI detection of a short burst
- GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
- Fermi trigger No 722462310: Global MASTER-Net observations report
- GRB 231115A: JinShan optical upper limits
- GRB 231116A: Fermi GBM Final Real-time Localization
- GRB 231115A: MASTER optical observations
- Integral GRB231115.65: Global MASTER-Net observations report
- GRB 231115A: GROWTH-India discovery of a potential optical counterpart
- Fermi GRB 231115A: Global MASTER-Net observations report
- GRB 231104A: VZLUSAT-2 detection
- GRB231111A: YAHPT Observations
- Swift GRB231110.89: Global MASTER-Net observations report
- IceCube-231103A: No candidates from the Zwicky Transient Facility
- Fermi GRB 231108A: Global MASTER-Net observations report
- GRB 231104A: Swift-BAT refined analysis
- Fermi trigger No 721006392: Global MASTER-Net observations report
- Fermi GRB 231106A: Global MASTER-Net observations report
- GRB 231104A: NuSTAR Observation of the prompt emission
- GRB 231104A: Fermi GBM Observation
- GRB 231104B: Fermi GBM Final Real-time Localization
- Fermi GRB 231103A: Global MASTER-Net observations report
- GRB 231104A: AstroSat CZTI detection
- GRB 231104A: Fermi-LAT detection
- GRB 231104A: Enhanced Swift-XRT position
- GRB 231104A: Swift detection of a bright burst
- GRB 231104A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S231102i: Global MASTER-Net observations report
- Fermi GRB 231030B: Global MASTER-Net observations report
- IceCube Alert 231027.18: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
- Fermi trigger No 719846439: Global MASTER-Net observations report
- GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
- GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
- Fermi GRB 231019A: Global MASTER-Net observations report
- GRB 231017A: JinShan optical upper limit
- GRB 231015A: Glowbug gamma-ray detection
- IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
- GRB 230906A: optical counterpart
- Fermi trigger No 716449174: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
- GRB 230911A: GOTO optical counterpart candidate
- GRB 230906A: Chandra detection of the X-ray afterglow
- GRB 230911C: Swift detection of a burst
- GRB 230906A: Swift-XRT observations
- IPN triangulation of GRB 230906A (short)
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- Fermi trigger No 715429986: Global MASTER-Net observations report
- Fermi GRB 230904A: Global MASTER-Net observations report
- GRB 230828A: AstroSat CZTI detection
- Fermi GRB 230827A: Global MASTER-Net observations report
- GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
- GRB 230826A: Swift detection of a burst
- Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
- Swift GRB230825.75: Global MASTER-Net observations report
- GRB 230812B: radio detection with the VLA
- Fermi trigger No 714618399: Global MASTER-Net observations report
- GRB 230812B: Assy optical observations, possible SN rise
- Swift GRB230820.81: Global MASTER-Net observations report
- Fermi GRB 230818A: Global MASTER-Net observations report