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"
28677 results found.
- IceCube-200929A: No neutrino counterpart candidates in ANTARES search
- IceCube-200926B: No significant detection in HAWC
- GRB 200928B: Insight-HXMT/HE detection
- IceCube-200926B: Upper limits from Fermi-GBM Observations
- IceCube-200926A: Upper limits from Fermi-GBM Observations
- IceCube-200926A: No significant detection in HAWC
- Fermi GRB 200929A: Global MASTER-Net observations report
- GRB 200928B: AstroSat CZTI detection
- IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
- Fermi-LAT Gamma-ray Observations of IceCube-200926B
- IceCube-200926B: No neutrino counterpart candidates in ANTARES search
- Swift-XRT observations of IceCube 200926A
- Konus-Wind detection of GRB 200920B
- Fermi-LAT Gamma-ray Observations of IceCube-200926A
- GRB 200925B: Swift-XRT refined analysis update
- GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)
- GRB 200925B: Swift-XRT refined Analysis
- GRB 200925B: Swift/UVOT Detection
- GRB 200925B: Swift-BAT refined analysis
- GRB 200922A: Chilescope optical observations
- Swift GRB 200925B: Global MASTER-Net OT detection
- GRB 200925B: OSN Afterglow Candidate Discovery
- Fermi GRB 200925A: Global MASTER-Net observations report
- Konus-Wind observation of GRB 200914A
- Fermi GRB 200924A: Global MASTER-Net observations report
- GRB 200922A: chance superposition between optical afterglow and archival star
- GRB 200922A: Insight-HXMT/HE detection
- Fermi GRB 200923A: Global MASTER-Net observations report
- GRB 200922A: Swift-BAT refined analysis
- Improved enhanced Swift-XRT position of GRB 200922A
- GRB 200922A: Swift/UVOT Detection
- Fermi-LAT Gamma-ray Observations of IceCube-200921A and detection of a new gamma-ray source, Fermi J1256.9+2630
- IceCube-200921A: no significant detection in HAWC observations
- Fermi GRB 200922B: Global MASTER-Net observations report
- GRB 200922A: LCO observations
- Swift GRB 200922A: Global MASTER-Net observations report
- GRB 200922A: Swift-XRT refined Analysis
- GRB 200917A: Swift/UVOT Upper Limits
- GRB 200919C: Insight-HXMT/HE detection
- IceCube-200921A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- IceCube-200921A: Upper limits from Fermi-GBM Observations
- IPN triangulation of GRB 200920B (short)
- GRB 200914A: Swift-XRT further observations
- IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia
- Fermi GRB 200919C: Global MASTER-Net observations report
- GRB 200919A: CrAO/ZTSh early optical upper limit
- Fermi GRB 200919B: Global MASTER-Net observations report
- GRB 200919A: Swift-BAT refined analysis
- GRB 200916B: MASTER optical observation
- IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
- GRB 200916B: AstroSat CZTI detection
- GRB 200917A: GROWTH-India Telescope optical upper limit.
- Swift-XRT observations of IceCube 200916A
- IceCube-200916A: No significant detection in HAWC
- GRB 200917A: Swift-BAT refined analysis
- IceCube-200916A: No neutrino counterpart candidates in ANTARES search
- Fermi-GBM Sub-Threshold Detection of GRB 200917A
- GRB 200917A: Swift-XRT refined Analysis
- IceCube-200916A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Swift GRB 200917A: Global MASTER-Net observations report
- IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
- IPN triangulation of GRB 200916B (short)
- IceCube-200916A: Upper limits from Fermi-GBM Observations
- Fermi-LAT Gamma-ray Observations of IceCube-200916A
- Swift-XRT observations of IceCube 200911A
- Fermi GRB 200916A: Global MASTER-Net observations report
- Fermi GRB 200914A: Global MASTER-Net observations report
- GRB 200914A: AGILE detection
- GRB 200914A: Swift-XRT observations
- GRB 200914A: Fermi GBM observation
- IceCube-200911A: No significant detection in HAWC
- Fermi-LAT Gamma-ray Observations of IceCube-200911A and detection of a new gamma-ray source, Fermi J0330.1+3743
- GRB 200914A: Swift ToO observations
- IceCube-200911A: No neutrino counterpart candidates in ANTARES search
- IceCube-200911A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- IceCube-200911A: not observable by Fermi-GBM
- GRB 200826A: uGMRT radio upper limit at 1.25 GHz
- IPN triangulation of GRB 200907A (short)
- GRB 200909B: Swift-BAT refined analysis
- GRB 200909A: AstroSat CZTI detection
- GRB 200829A: T100 observations
- Fermi GRB 200909A: Global MASTER-Net observations report
- GRB 200907B: Swift/UVOT Upper Limits
- Fermi GRB 200908A: Global MASTER-Net observations report
- GRB 200907B: Swift-BAT refined analysis
- Konus-Wind detection of GRB 200903E
- GRB 200907B: AstroSat CZTI detection
- GRB 200907B: Swift-XRT refined Analysis
- GRB 200907B: MITSuME Okayama optical upper limits
- Swift GRB 200907B: Global MASTER-Net observations report
- Fermi GRB 200907C: Global MASTER-Net observations report
- Correction to GCN 28387: GRB 200907B GROWTH-India optical upper limit
- GRB200907A: GROWTH-India optical upper limit
- Fermi GRB 200906A: Global MASTER-Net observations report
- IPN triangulation of GRB 200903E
- GRB 200906A: EMIR/GTC NIR upper limit
- GRB 200906A: LBT near-infrared upper limit
- GRB 200906A: Swift-BAT refined analysis
- GRB 200906A: Swift/UVOT Upper Limits
- GRB 200906A: GROWTH-India Telescope (GIT) optical r band upper limit