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.
- LIGO/Virgo S190425z - GROWTH-India follow-up of two ZTF candidates
- LIGO/Virgo S190425z: KPED Follow-Up Observations
- LIGO/Virgo S190425z: Lulin Follow-Up Observations
- LIGO/Virgo S190425z: AGILE-GRID Observations
- LIGO/Virgo S190421ar: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190422A: Fermi GBM detection
- GRB 190422A: Swift-XRT refined Analysis
- LIGO/Virgo S190421ar: INTEGRAL prompt observation
- 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
- INTEGRAL prompt observation of S190412m
- 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
- INTEGRAL observation of S190408an
- 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
- Fermi-LAT Gamma-ray Observations of IceCube-190331A
- GRB 190331A: Fermi GBM detection
- MAGIC follow-up of the X-ray flares of LS I +61�303 dete
- GRB 190326B: Fermi GBM detection
- GRB 190324A: Swift-XRT refined Analysis
- GRB 190324A: Fermi GBM observation
- Further Chandra observations of GW170817 ~581-583 days since merger
- GRB 190320A: Swift-XRT refined Analysis
- GRB 190320A: Fermi GBM observation
- GRB 190311A: Fermi GBM observation
- GRB 190311A: Swift-XRT refined Analysis
- GRB 190311A: NEXT-0.6m optical afterglow detection
- GRB 190305A: Swift-XRT afterglow detection
- GRB 190306A: Swift-XRT observations
- GRB 190305A: Swift-XRT observations
- INTEGRAL observation of IceCube-190221A
- IceCube-190221A: Fermi-LAT Gamma-ray observations
- GRB 190220B: Fermi GBM observation
- GRB 190220A: Swift-XRT refined Analysis
- GRB 190219A: Swift-XRT refined Analysis
- GRB 190215A: Fermi GBM detection
- GRB 190211A: DOAO optical observation
- GRB 190211A: Swift-XRT refined Analysis
- GRB 190211A: NEXT-0.6m optical afterglow detection
- GRB 190202A: SAO RAS further optical observations
- GRB 190204A: SAO RAS optical observations
- GRB 190203A: Swift-XRT refined Analysis
- GRB 190204A: Swift-XRT refined Analysis
- GRB 190202A: R and I band observation from HCT
- GRB 190203A: SAO RAS optical observations, afterglow fading
- GRB 190202A: SAO RAS optical observations
- GRB 190202A: Swift-XRT refined Analysis
- GRB 190202A: Fermi GBM observation
- GRB 190129B: Swift-XRT candidate afterglow detection
- Fermi GBM Observations of IceCube-190124A
- GRB 190129A: Fermi GBM detection
- INTEGRAL observation of IceCube-190124A
- Fermi-LAT Gamma-ray Observations of IceCube-190124A
- GRB 190123A: Swift-XRT refined Analysis
- GRB 190123A: Fermi GBM observation
- GRB 190122A: Fermi GBM observation
- GRB 190122A: Fermi-LAT detection
- GRB 190114C: RTT150 optical observations
- GRB 190114B: Swift-XRT refined Analysis
- GRB 190114C: Mondy optical observations
- GRB 190114C: A type 1 BdHN with TeV emission
- GRB 190114C: Fermi-LAT detection
- GRB 190114C: Fermi GBM detection
- GRB 190114C: Swift-XRT refined Analysis
- INTEGRAL observation of IceCube-190104A
- GRB 190114A: Swift-XRT refined Analysis
- GRB 190110A: Fermi GBM detection
- GRB 190109B: Fermi GBM observation
- GRB 190106A: OSN Afterglow Observations
- GRB 190109B: Swift-XRT refined Analysis
- GRB 190109A: Fermi GBM observation
- GRB 190109A: Swift-XRT refined Analysis
- GRB 190106A: Swift-XRT refined Analysis
- Fermi LAT Gamma-ray Observations of IceCube-190104A
- GRB 190103B: Swift-XRT refined Analysis
- GRB 181231A: Fermi GBM detection
- GRB 181231A: Fermi-LAT detection
- 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 181228A: Fermi GBM observation
- GRB 181227A: Fermi GBM detection
- GRB 181225A: Swift observations and X-ray candidate afterglow
- GRB 181225A: Fermi GBM detection
- GRB 181225A: Fermi-LAT Detection
- Konus-Wind observation of GRB 181222B
- GRB 181222B : Fermi GBM detection
- GRB 181222A: Fermi GBM observation
- GRB 181213A: Swift-XRT refined Analysis
- GRB 181212A: Fermi GBM Detection
- GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)
- GRB 181203A: Swift-XRT refined Analysis
- GRB 181201A: Swift/UVOT Detection
- GRB 181202A: Swift-XRT refined Analysis
- GRB 181201A: optical observations in Chilescope observatory