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"
6098 results found.
- GRB 201008A: Fermi GBM observation
- GRB 210323B: Fermi GBM observation
- Fermi GRB 210615A: Global MASTER-Net observations report
- Swift ToO Observations of HAWC transient J0020+3108
- GRB 210605B: Swift-XRT afterglow detection
- GRB 210610A: Fermi GBM observations
- GRB 210610B: Further SAO RAS optical observations
- GRB 210610A: SAO RAS optical observations
- GRB 210610B: optical observations from Burke-Gaffney Observatory and Abbey Ridge Observatory
- GRB 210421B: Fermi GBM detection
- GRB 201228B: Fermi GBM observation
- GRB 210610A: CAHA 2.2m observations and light-curve behavior
- GRB 210606A: Fermi GBM detection
- GRB 210605B: Fermi GBM detection
- GRB 210610B: Swift-XRT refined Analysis
- GRB 210610B: Fermi GBM detection
- Konus-Wind detection of GRB 210610A
- Konus-Wind detection of GRB 210610B
- GRB 210610A: Swift-XRT refined Analysis
- GRB 210610B: iTelescope optical afterglow observations
- GRB 210606A: Swift-XRT afterglow detection
- GRB 210610A: GIT optical detection
- Fermi-LAT Gamma-ray Observations of IceCube-210608A
- GRB 210606B: Fermi GBM detection
- GRB 210605B: Swift-XRT observations
- Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
- Swift J1555.2-5402: Swift XRT refined analysis of the new SGR
- NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
- GRB 210528A: Fermi GBM detection
- GRB 210527A: GIT optical upper limit
- GRB 210527A: Swift-XRT refined Analysis
- GRB 210520A: Swift-XRT observations
- GRB210413B: further Swift-XRT observations
- GRB 210520A: Fermi GBM detection
- GRB 210520A: Fermi-LAT detection
- Fermi GBM observation of a bright burst from magneta
- Fermi-LAT Gamma-ray Observations of IceCube-210516A
- GRB 210517A: Swift-XRT refined Analysis
- IceCube-210516A: No significant detection in HAWC
- GRB 210515C: Swift-XRT refined Analysis
- GRB 210514A: Swift-XRT refined Analysis
- GRB 210514A: update on the BAT trigger time and burst duration
- GRB 210511B: Fermi GBM observation
- Fermi-LAT Gamma-ray Observations of IceCube-210510A
- GRB 210509A: Swift-XRT refined Analysis
- Fermi-LAT Gamma-ray Observations of IceCube-210503A and detection of a new gamma-ray source, Fermi J0931.9+3633
- GRB 210506A: Swift-XRT observations
- Alert from the HAWC Burst Monitor HAWC-210507A
- GRB 210504A: Swift-XRT refined Analysis
- GRB 210504A: MITSuME Akeno optical upper limits
- GRB 210413B: Swift/UVOT Observations
- GRB 210323B: Swift-XRT observations
- Swift Trigger 1045571 is not a GRB
- GRB 210422B: Fermi GBM Final Localization
- GRB 210421B: Swift-XRT observations
- GRB 210420B: Swift-XRT refined Analysis
- GRB 210421A: Swift-XRT refined Analysis
- GRB 210419A: Swift-XRT refined Analysis
- GRB 210413B: Swift-XRT observations
- GRB 210410A: A twin of short GRB 090510 with complementary observations
- GRB 210411C: Swift-XRT refined Analysis
- GRB 210410A: Swift-XRT refined Analysis
- GRB 210410A: Fermi GBM detection
- GRB 210406A: Swift-XRT observations
- GRB 210410A: Fermi-LAT detection
- GRB 210406B: Fermi GBM detection
- GRB 210406A: Fermi GBM detection
- GRB 210402A: Fermi GBM detection
- GRB 210402A: Swift-XRT refined Analysis
- GRB 210323A: Fermi GBM detection
- GRB 210323A: Swift-XRT refined Analysis
- GRB 210321A: Swift-XRT refined Analysis
- GRB 210318A: Swift-XRT refined Analysis
- GRB 210318B: Fermi GBM detection
- GRB210318B: Swift detection of a burst
- GRB 210226A: GIT optical upper limit
- GRB 210306A: HCT optical upper limit
- GRB 210306B: Fermi GBM detection
- GRB 210305A: Fermi GBM observation
- GRB 210308A: Fermi GBM detection
- GRB 210305A: Swift-XRT refined Analysis
- GRB 210307A: Swift-XRT refined Analysis
- GRB 210306A: Swift-XRT refined Analysis
- GRB 210306A: Fermi GBM observation
- GRB 210306A: iTelescope T24 optical observations
- GRB 210306A: Fermi-LAT detection
- GRB 210306A: iTelescope optical afterglow observations
- GRB 210217A: 3.6m DOT optical observations
- GRB 210226A: Fermi GBM detection
- GRB 210226A: Swift-XRT refined Analysis
- GRB 210218A: Swift-XRT confirmation of afterglow
- GRB 210222B: Swift-XRT refined Analysis
- GRB 210218A: Swift/UVOT observations
- GRB 210218A: Swift-XRT observations
- GRB 210217A: Swift-XRT refined Analysis
- GRB 210205A: observations with the 3.6m DOT, a potential dark burst?
- Fermi/GBM observation of a burst from SGR 1830-0645
- GRB 210210A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
- GRB 210212A: Swift-XRT refined Analysis
- GRB 210204A: observations with the 3.6m Devasthal Optical Telescope and possible jet break