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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

22 results found.

  1. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  2. GRB 250814A: Swift/UVOT Upper Limits
  3. GRB 250814A: Further GRAWITA TNG NIR observations
  4. GRB 250814A: Swift-BAT refined analysis
  5. GRB 250814A: Further COLIBRÍ optical upper limit
  6. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  7. GRB 250814A: GRAWITA TNG NIR observations
  8. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  9. GRB250814A: TRT optical upper limits
  10. GRB 250814A: P200/WIRC observations of the afterglow candidate
  11. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  12. GRB 250814A: KAIT optical upper limit
  13. GRB 250814A: Swift-XRT refined Analysis
  14. GRB 240814A: Fermi GBM Observation
  15. GRB 250814A: Possible afterglow candidate from P200/WIRC
  16. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  17. GRB 250814A: J-band upper limit from WINTER
  18. GRB 250814A: COLIBRÍ optical upper limit
  19. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  20. GRB 250814A: DDOTI Optical Upper Limit
  21. GRB 250814A: Swift detection of a burst coincident with a subthreshold GW trigger
  22. GRB 250814A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive:
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