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"
3040 results found.
- GRB 190604B: Swift-XRT refined Analysis
- LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
- GRB 190531B: Swift-XRT afterglow detection
- GRB 190530A: Swift/UVOT Detection
- GRB 190530A: Swift-XRT afterglow detection
- IceCube-190504A: Kanata optical/NIR follow-up observations
- LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
- LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
- LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190519A: Swift-XRT refined Analysis
- LIGO/Virgo S190426c: NICER X-ray Follow-Up of ZTF19aassfws
- LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190515B: Swift-XRT refined Analysis
- LIGO/Virgo S190510g: Swift-XRT observations and results
- LIGO/Virgo S190513bm: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO-Virgo S190512at: AGILE GRID observations
- LIGO/Virgo S190512at: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190511A: Swift-XRT refined Analysis
- GRB 190511A: Swift/UVOT Detection
- LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
- LIGO/Virgo S190510g: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190501A: Swift XRT and UVOT Observations
- LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
- LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
- LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
- LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient
- LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
- LIGO/Virgo S190426c: Swift-XRT sources
- LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometry of ZTF19aarykkb and ZTF19aarzaod
- LIGO/Virgo S190421ar: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190422A: Swift-XRT refined Analysis
- LIGO/Virgo S190408an: INTEGRAL follow-up observations
- GRB 190326A: Swift XRT and UVOT follow-up observations
- LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190409A: ground analysis reveals a likely spurious event
- LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190409A: Swift detection of a possible burst
- GRB 190404C: Swift-XRT afterglow detection
- GRB 190404C: Swift-XRT observations
- Swift GRB 190331B: Further Swift-XRT observations
- GRB 190331B: Swift observations of a ground-detected burst
- GRB 190324A: Swift-XRT refined Analysis
- Further Chandra observations of GW170817 ~581-583 days since merger
- SWIFT GRB190323.85 Global MASTER-Net observations report
- GRB 190320A: Swift-XRT refined Analysis
- GRB 190311A: Swift-XRT refined Analysis
- GRB 190305A: Swift-XRT afterglow detection
- GRB 190306A: Swift-XRT observations
- GRB 190305A: Swift-XRT observations
- GRB 190220A: Swift-XRT refined Analysis
- GRB 190219A: Swift-XRT refined Analysis
- GRB 190211A: Swift-XRT refined Analysis
- GRB 190203A: Swift-XRT refined Analysis
- GRB 190204A: Swift-XRT refined Analysis
- GRB 190202A: Swift-XRT refined Analysis
- GRB 190129B: Swift-XRT candidate afterglow detection
- GRB 190123A: Swift-XRT refined Analysis
- GRB 190114B: Swift-XRT refined Analysis
- GRB 190114C: Swift-XRT refined Analysis
- GRB 190114A: Swift-XRT refined Analysis
- GRB 190109B: Swift-XRT refined Analysis
- GRB 190109A: Swift-XRT refined Analysis
- GRB 190106A: Swift-XRT refined Analysis
- GRB 190103B: Swift-XRT refined Analysis
- GRB 181225A: further Swift-XRT observations
- GRB 181228A: Swift-XRT refined Analysis
- GRB 181222B: Swift follow-up observations of MASTER optical transient J204928.79+245744.0
- GRB 181225A: Swift observations and X-ray candidate afterglow
- GRB 181213A: Swift-XRT refined Analysis
- GRB 181203A: Swift/UVOT Upper Limits
- GRB 181203A: Swift-XRT refined Analysis
- GRB 181201A: Swift/UVOT Detection
- GRB 181202A: Swift-XRT refined Analysis
- GRB 181201A: Swift-XRT afterglow detection
- GRB 181126A: No Ks-band afterglow detection with Keck I
- GRB 181126A: Swift-XRT refined Analysis
- GRB 181123B: Swift-XRT refined Analysis
- Swift Trigger 872470: further Swift analysis
- GRB 181110A: Swift-XRT refined Analysis
- GRB 181103A: Swift-XRT refined Analysis
- GRB 181030A: Swift-XRT refined Analysis
- GRB 181022A: Swift-XRT refined Analysis
- GRB 181023A: Swift-XRT refined Analysis
- GRB 181020A: Swift-XRT refined Analysis
- GRB 181013A: Swift detection of a probable burst
- GRB 181010A: Swift-XRT refined Analysis
- GRB 181003A: Swift-XRT afterglow detection
- GRB 181002A: Swift-XRT refined Analysis
- GRB 180930A: Swift-XRT refined Analysis
- GRB 180925A: Swift-XRT refined Analysis
- GRB 180924A: Swift-XRT refined Analysis
- GRB 180914B: Swift-XRT afterglow detection
- GRB 180914A: Swift-XRT observations
- GRB 180905A: Swift-XRT refined Analysis
- GRB 180904A: Swift-XRT refined Analysis
- GRB 180829A: Swift-XRT observations
- GRB 180828A: Swift-XRT refined Analysis