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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"

40 results found.

  1. GRB 250314A: ALMA detection
  2. GRB 160521B: Theoretical estimate of the redshift and urgent need for further x-ray observations
  3. GRB 131202A: theoretical estimation of the redshift
  4. GRB 120923A: Gemini afterglow detection, high-z candidate
  5. GRB 090423: Spitzer observations of the z~8.3 burst
  6. GRB 090423: WSRT Radio Observations
  7. GRB 090423: Fermi GBM T90 follow-up analysis results
  8. GRB 090423: optical limit
  9. GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
  10. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  11. GRB 090423: CARMA mm observations
  12. GRB 090423: millimeter detection
  13. GRB 090426 Keck LRIS redshift
  14. GRB 090423: GROND second epoch imaging and refined SED
  15. GRB 090423: Fermi GBM observation (correction of isotropic equivalent energy)
  16. VLA radio observation of high-z GRB 090423
  17. GRB 090423: Y-band field calibration update/correction
  18. GRB 090423: Swift/BAT spectral lag results
  19. GRB 090423: energetic, luminosity and jet break
  20. GRB 090423: Fermi GBM observation
  21. GRB 090423: Ep,i - Eiso correlation
  22. GRB 090423: Refined TNG analysis
  23. GRB 090423 limiting magnitudes
  24. GRB 090423: VLT/ISAAC spectroscopy
  25. GRB 090423: Near infrared observation at Okayama Observatory
  26. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  27. GRB 090423: TNG Amici spectrum
  28. GRB 090423: GROND detection and preliminary photo-z
  29. GRB 090423: NOT z-band limit
  30. GRB 090423: Correction to NIR photometry
  31. GRB 090423: Swift-XRT refined analysis
  32. GRB090423 - Swift/UVOT upper limits.
  33. GRB 090423: NIR photometry and evidence for spectral break
  34. GRB 090423: UKIRT data further analysis
  35. GRB 090423: Enhanced Swift-XRT position
  36. GRB 090423: Swift-BAT refined analysis
  37. GRB 090423: UKIRT K-band observations
  38. GRB 090423: P60 Observations
  39. GRB 090423: Faulkes Telescope South observations
  40. GRB 090423: Swift detection of a burst

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