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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').

15 results found.

  1. GRB 170531B: Zeiss-1000/CrAO optical observations
  2. GRB 170531B: WHT spectroscopy
  3. GRB 170531B: ISON/Terskol optical observations
  4. GRB 170531B: Swift/UVOT Detection
  5. GRB 170531B: SMARTS optical/IR observations
  6. GRB 170531B: Swift-BAT refined analysis
  7. GRB 170531B: LCO observations
  8. GRB 170531B: Swift-XRT refined Analysis
  9. GRB 170531B: MASTER Net optical counterpart refind position and magnitude
  10. GROND observations of GRB 170531B
  11. GRB 170531B: Redshift from GTC/OSIRIS
  12. GRB 170531B: Enhanced Swift-XRT position
  13. GRB 170531B: CrAO confirmation of the afterglow
  14. GRB 170531B: MASTER Net OT detection
  15. GRB 170531B: Swift detection of a burst


Download all Circulars as a .tar.gz archive:
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