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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"

67 results found.

  1. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  2. GRB 171205A: Likely association with low-z spiral galaxy
  3. LIGO/Virgo G194575: INAF-Asiago Telescope further analysis of iPTF candidates
  4. GRB 120422A: Additional Gemini observations and Keck/LRIS spectroscopy
  5. GRB 120422A: VLT/X-shooter spectroscopy of the GRB counterpart
  6. GRB 111211A: Detection of the SN with the 10.4m GTC
  7. GRB 111209A: Swift UVOT refined analysis
  8. GRB 111209A: Swift Burst of Interest
  9. GRB 101225A Late-time emission observed by Swift-BAT
  10. GRB 101225: Optical follow-up of the Christmas burst
  11. Tentative redshift of GRB101225A (Christmas's burst) from Swift-XRT data
  12. Redshift solution(s) for GRB101213A from Swift-XRT data
  13. GRB 100925A: Nearby DSS Source - SN-GRB or new Galactic transient?
  14. GRB 100418A: Possible Evidence for a Supernova
  15. GRB 100316D: ATCA radio observations
  16. GRB 100316D: Pre-burst emission measured by BAT
  17. GRB 100316D: GROND Detection of the Optical/NIR Afterglow Candidate
  18. GRB 100316D: Swift-BAT refined analysis
  19. GRB 080307: Swift-XRT Team refined analysis
  20. Discovery of Radio Emission from Transient in NGC 2770
  21. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  22. GRB 070419A, deep LBT photometry and possible supernova detection
  23. GRB 060218 / SN 2006aj Nebular Spectrum
  24. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  25. GRB 060614: SMARTS host galaxy observations
  26. GRB 060614: spectroscopy
  27. GRB 060614: optical observations
  28. GRB 060418 : IR afterglow observations
  29. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  30. GRB060218, optical observations
  31. GRB 060218/SN 2006aj, LNA optical observation
  32. GRB 060218/SN 2006aj, high resolution spectra
  33. GRB 060218: RTT150 optical observations
  34. GRB060218/SN 2006aj: optical observation in V
  35. GRB060218/SN 2006aj: optical observation
  36. GRB 060218 : GMRT observation [Correction and Improvement]
  37. GRB 060218/SN 2006aj: K-380 optical observations
  38. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  39. GRB 060218/SN 2006aj: ABT observations
  40. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  41. GRB 060218 : Radio upper limits from GMRT
  42. GRB 060218/SN 2006aj: WIRO optical observations
  43. GRB 060218/SN 2006aj: RBO optical observations
  44. GRB 060218: Refined analysis of the radio afterglow
  45. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  46. GRB 060218: rebrightening
  47. GRB 060218/SN 2006aj: optical observations
  48. GRB 060218: rebrightening
  49. GRB 060218: emergence of the underlying SN spectrum
  50. GRB 060218: Decline in r-band flux
  51. GRB 060218: spectroscopic observations
  52. GRB 060218: Further refined analysis of the Swift-BAT burst
  53. GRB 060218: Likely an underluminous GRB
  54. GRB060218: Optical Spectroscopy of GRB-SN
  55. GRB 060218: Optical Observations at Xinglong Obs.
  56. GRB060218: UV Detection and Light Curves
  57. GRB060218: Radio Afterglow Discovery
  58. GRB 060218: MDM Redshift
  59. GRB 060218: optical/nIR observations at La Palma
  60. Oddball GRB 060218, transient or GRB?
  61. Brightening of the Optical Counterpart of the Possible GRB 060218
  62. GRB 060218: MDM Observations
  63. GRB 060218: Pre-burst detection of a possible host galaxy
  64. Preliminary refined analysis of the Swift-BAT trigger 191157
  65. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  66. GRB 060218: Swift XRT Position
  67. GRB 060218: Swift-BAT detection of a possible burst

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