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"28097 results found.
- ZTF20acozryr/AT2020yxz (GRB 201103B): SAO RAS optical observations
- IceCube 201114A: Swift followup of Fermi J0703.5+0505
- INTEGRAL Weak#8825: AROMA-N Optical Observation
- Fermi-LAT Gamma-ray Observations of IceCube-201114A
- GRB 201116A: Swift-XRT afterglow detection
- GRB 201116A: OSN Afterglow Candidate
- Swift Trigger 1006917 is Be/X-ray binary pulsar 1A 0535+262
- IceCube Alert 201115.67: Global MASTER-Net observations report
- IceCube-201115A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-201114A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-201115A: No significant detection in HAWC
- IceCube-201114A: No significant detection in HAWC
- IceCube-201115A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- INTEGRAL Weak#8811: AROMA-N Optical Observation
- IceCube-201115A: No neutrino counterpart candidates in ANTARES search
- IceCube Alert 201115.09: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-201115A
- GRB 201116A: BALROG localization (Fermi Trigger 627180592 / GRB 201116035)
- Swift XRT observations of the Fermi-LAT source 4FGL J0658.6+0636, positionally consistent with the IceCube high-energy neutrino alert
- VLASS identifies possible radio counterparts to IceCube-201115A, including a bright BL Lac candidate
- Swift-XRT observations of IceCube 201114A
- IceCube-201114A: No neutrino counterpart candidates in ANTARES search
- GRB 201114A: AstroSat CZTI detection
- Fermi-LAT Gamma-ray Observations of NuEm-201107A
- ZTF20acozryr/AT2020yxz (GRB 201103B): Flattening of the optical light curve
- Swift Trigger 1005428: Detection of SGR 1830-0645
- ZTF20acozryr (GRB 201103B): GROWTH-India Telescope optical observations
- GRB 201104B: continued TSHAO optical observation
- GRB 201104B: MITSuME Akeno optical observation
- GRB 201103B: GMG observation (2nd epoch)
- GRB201103B: GMG observation
- GRB 201104A: Swift-XRT observations
- Swift XRT and UVOT detection of ZTF20acozryr/AT2020yxz/GRB201103B
- GRB 201104B: Kitab optical observations
- GRB 201103B (ZTF20acozryr/AT2020yxz): Xinglong-2.16m optical observations
- Fermi trigger No 626247072: Global MASTER-Net observations report
- GRB 201104B: TSHAO optical observation
- GRB 201104B: Swift/UVOT Detection
- GRB 201104B: Swift-XRT refined Analysis
- GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
- GRB 201105A: Swift detected burst and BAT refined analysis
- IPN triangulation of GRB 201103B (consistent with ZTF20acozryr/AT2020yxz)
- GRB 201105B: Fermi GBM observation
- GRB 201105A: BALROG localization (Fermi Trigger 626247072 / GRB 201105230)
- ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
- GRB 201104B: VLT/X-shooter redshift
- GRB 201104B: Swift-BAT refined analysis
- Swift Trigger 1004219: Detection of SGR 1830-0645
- GRB 201104A: BALROG localization (Fermi Trigger 626140861 / GRB 201104001)
- GRB 201104A: Fermi GBM observation
- GRB 201104B: Swift/UVOT Detection
- GRB 201104B: MASTER optical observation
- GRB 201104B: Swift detection of a burst
- GRB 201015A: Late X-ray Detections with Chandra
- GRB 201031B: BALROG localization (Fermi Trigger 625859489 / GRB 201031744)
- GRB 201029A: Swift-BAT refined analysis
- IceCube 201021A: Swift follow-up of Fermi J1725.5+1312
- GRB 201029A: Swift/UVOT Upper Limits
- GRB 201029A: Fermi GBM detection
- GRB 201029A: Swift-XRT refined Analysis
- GRB 201029A: BOOTES-1 optical upper limit
- GRB 201029A: Enhanced Swift-XRT position
- GRB 201029A: Swift detection of a burst
- GRB 201027A: MITSuME Akeno optical upper limits
- GRB 201027A: Swift-BAT refined analysis
- GRB 201026A: Swift-BAT refined analysis
- GRB 201027A: Swift/UVOT Upper Limits
- GRB 201027A: Swift-XRT refined Analysis
- GRB 201026A: Fermi GBM detection
- GRB 201026A: Swift-XRT refined Analysis
- Baksan Neutrino Observatory Alert 201027.41: Global MASTER-Net observations report
- GRB 201026A: Swift/UVOT Upper Limits
- GRB 201027A: Enhanced Swift-XRT position
- GRB 201026A: Enhanced Swift-XRT position
- GRB 201020A: 1.3m DFOT, optical upper limits
- GRB 201027A: Swift detection of a burst
- GRB 201026A: NanShan/NEXT-0.6m optical upper limit
- GRB 201026A: Swift detection of a burst
- GRB 201024A: MITSuME Akeno optical upper limits
- GRB 201024A: Swift-BAT refined analysis
- GRB 201020B: HCT and GIT continued optical follow-up observations
- GRB 201024A: Swift-XRT refined Analysis
- GRB 201024A: Swift/UVOT Detection
- GRB 201020B: follow-up observations with Savelli Telescope
- GRB 201024A: VIRT optical observations
- GRB 201024A: Enhanced Swift-XRT position
- GRB 201020B: Redshift from GTC/OSIRIS
- GRB 201024A: Redshift from GTC/OSIRIS
- GRB 201024A: Swift detection of a burst with an optical afterglow
- Swift GRB201024A: Global MASTER-Net OT detection
- IceCube-201021A: No significant detection in HAWC
- IceCube-201021A: Optical counterpart of WISEA J172314.13+142101.5
- GRB 201021C: Swift-BAT refined analysis
- GRB 201021C: Swift-XRT refined Analysis
- GRB 201020B: GROWTH-India Telescope optical observations
- Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
- GRB 201020B: Konkoly Obs. optical detection
- Swift-XRT observations of IceCube 201021A (2)
- GRB 201020A: GROWTH-India Telescope late-time optical upper limit