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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
3036 results found.
- GRB 220921A: Swift-XRT Observations
- GRB 220909A: Swift-XRT observations
- GRB 220831A: Gemini-South Infrared Observations
- GRB 220907A: Swift-XRT refined Analysis
- GRB 220907A: Swift-XRT position
- GRB 220831A: Swift-UVOT Upper Limits
- GRB 220831A: Swift-XRT observations
- GRB 220826A: Swift-XRT refined Analysis
- GRB 220810A: Further Swift-XRT observations
- GRB 220813A: Swift-XRT refined Analysis
- GRB 220810A: Swift-XRT observations
- GRB 220730A: Swift-XRT afterglow detection
- GRB 220730A: Swift-XRT observations
- GRB 220715B: Swift-XRT refined Analysis
- GRB 220714B: Swift-XRT refined Analysis
- GRB 220711B: 10.4 m GTC(+EMIR) observations
- GRB 220711B: 10.4 m GTC(+EMIR) observations
- GRB 220710A: Swift-XRT afterglow detection
- GRB 220711B: Swift-XRT refined Analysis
- GRB 220708A: Swift-XRT refined Analysis
- GRB 220708B: Swift-XRT afterglow detection
- GRB 220706A: Swift-XRT refined Analysis
- GRB 220701A: Swift-XRT refined Analysis
- GRB 220627A: Swift-XRT afterglow detection
- Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
- GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
- GRB 220623A: Swift-XRT refined Analysis
- GRB 220611A: Continued Gemini Infrared Observations
- GRB 220618A: Swift-XRT refined Analysis
- GRB 220617A: Swift-XRT observations
- GRB 220611A: Gemini Ks counterpart detection
- GRB 220611A: Gemini South Infrared Detection
- GRB 220611A: Swift-XRT refined Analysis
- GRB 220606B: Swift follow-up observations
- GRB 220527A: Swift/UVOT detection
- GRB 220527A: Swift-XRT afterglow detection
- Fermi GRB 220523A: Global MASTER-Net observations report
- GRB 220521A: Swift-XRT refined Analysis
- GRB 220518A: Swift-XRT refined Analysis
- Continued Chandra monitoring of GW170817 at ~4.8 yr post-merger
- GRB 220514B: Swift-XRT observations
- GRB 220511A: Swift-XRT afterglow detection
- GRB 220511A: Swift-XRT observations
- GRB 220506A: Swift-XRT afterglow detection
- GRB 220430A: Swift-XRT refined Analysis
- GRB 220426A: Swift-XRT and UVOT observations
- GRB 220427A: Swift-XRT refined Analysis
- GRB 220418B: Swift-XRT observations
- GRB 220403C: Further Swift-XRT observations
- GRB 220412B: Swift-XRT observations
- GRB 220412A: Swift-XRT refined Analysis
- GRB 220403C: Swift-XRT observations
- GRB 220408A: Swift-XRT refined Analysis
- Chandra upper limit at the location of GRB 220408A
- GRB 220403B: Swift-XRT refined Analysis
- GRB 220325A: Swift-XRT refined Analysis
- GRB 220319A: Swift-XRT refined Analysis
- GRB 220310C: Swift-XRT observations
- GRB 220306B: Swift-XRT refined Analysis
- GRB 220305A: Swift-XRT refined Analysis
- GRB 220302A: Swift-XRT refined Analysis
- GRB 220219B: Swift-XRT observations
- ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
- ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
- IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220117B: Swift-XRT refined Analysis
- GRB 220117A: Swift-XRT refined Analysis
- Confirmation of the X-ray afterglow of GRB 220107B
- GRB 220107A: Swift/UVOT Detection
- GRB 220107B: Swift-XRT afterglow detection
- GRB 220107A: Swift-XRT afterglow detection
- GRB 220101A: Swift-XRT refined Analysis
- GRB 211229A: Swift-XRT and UVOT observations
- Fermi GRB 211229B: Global MASTER-Net observations report
- GRB 211227A: Swift-XRT refined Analysis
- GRB 211221A: Swift-XRT refined Analysis
- GRB 211106A: XMM-Newton monitoring campaign detections
- GRB 211211A: Swift-XRT refined Analysis
- Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
- GRB 211207A: Swift-XRT refined Analysis
- GRB 211129A: Swift-XRT refined Analysis
- Chandra observations of GRB 210905A
- GRB 211106A: Swift/UVOT upper limits
- GRB 211107B: Swift-XRT afterglow detection
- GRB 211106A: Swift-XRT afterglow detection
- GRB 211107B: Swift-XRT observations
- GRB 211106A: Swift-XRT observations
- Swift Trigger 1082569 is probably not a GRB
- GRB 211024A: Swift-XRT observations
- GRB 211018A: Swift-XRT observations
- GRB 211025A: Swift-XRT refined Analysis
- GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
- GRB 211024B: Swift-XRT refined Analysis
- GRB 211023B: Swift-XRT refined Analysis
- GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
- GRB 210928A: Swift-XRT refined Analysis
- GRB 210930A: Swift/UVOT Upper Limits
- GRB 210930A: Swift-XRT refined Analysis
- GRB 210919A: Swift-XRT refined Analysis
- GRB 210912A: Swift-XRT refined Analysis