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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.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
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"

20 results found.

  1. IceCube-201221A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube-201221A: No significant detection in HAWC
  3. GRB 201221A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  4. GRB 201221A: REM early-time afterglow detection
  5. IceCube-201221A: Upper limits from Insight-HXMT/HE observations
  6. Fermi-LAT Gamma-ray Observations of IceCube-201221A
  7. GRB 201221A: Swift-BAT refined analysis
  8. correction to GCN 29110 - Fermi GBM Sub-Threshold Detection of GRB 201221A
  9. Fermi GBM Sub-Threshold Detection of GRB 201221A
  10. GRB 201221A: Swift/UVOT Upper Limits
  11. GRB 201221A: Swift-XRT refined Analysis
  12. GRB 201221A: Enhanced Swift-XRT position
  13. IceCube-201221A: not observable by Fermi-GBM
  14. IceCube-201221A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  15. IceCube-201221A: IceCube observation of a high-energy neutrino candidate event
  16. GRB 201221A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 5.7
  17. GRB 201221A: FRAM-Auger optical limit
  18. Swift GRB 201221A: Global MASTER-Net observations report
  19. GRB 201221A: Prompt enhanced Swift-XRT position
  20. GRB 201221A: Swift detection of a burst

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Download all Circulars as a .tar.gz archive:
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