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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"

22073 results found.

  1. HETE Trigger #1760 (GRB 010920B?): a new optical source
  2. HETE Trigger #1759 (GRB 010920?) optical observations
  3. GRB000926, Host Galaxy Observations
  4. GRB001109, Host Galaxy Spectroscopic Observations
  5. GCN and HETE status
  6. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  7. GRB 010222 - WHT BVRI images
  8. GRB 010629 Optical Observations
  9. GRB010629: Optical Observations
  10. SGR1900+14: High Fluence Burst Localized by HETE
  11. GRB010629, optical observations
  12. IPN triangulation of GRB010629
  13. GRB010629: A Burst Localized by HETE
  14. SGR1900+14: Second Burst Localized by HETE
  15. SGR1900+14: A Burst Localized by HETE
  16. SGR1806-20: A Second, Intense Burst Localized by HETE
  17. SGR1806-20: Localization by HETE
  18. IPN triangulation of GRB010613
  19. IPN triangulation of GRB010612
  20. HETE Fully-Automated GCN Notices
  21. GRB000301C: Late-time HST/STIS observation
  22. GRB010518: a faint BeppoSAX detection
  23. GRB000418: HST/STIS Second-epoch Observations
  24. X-ray precursors to the large flare from SGR 1900+14
  25. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  26. Millimeter observation of SGR 1900+14
  27. SGR 1900+14: Detection of extended X-ray emission
  28. SGR 1900+14, Chandra observations
  29. SGR1900+14, I-band observations
  30. GRB010412, field photometry
  31. Giant flare from SGR1900+14
  32. GRB 010326b Optical Observations
  33. GRB010412: BeppoSAX GRBM and WFC observations
  34. IPN Triangulation of GRB010412
  35. GRB Observation Report
  36. GRB010324, revised field photometry
  37. REVISED LOCATION OF GRB010326A
  38. GRB 980326: Late-time HST/STIS observations
  39. GRB010324, field photometry
  40. GRB010326B, field photometry
  41. GRB010326, field photometry
  42. GRB010220, field photometry
  43. Further Optical Observations of GRB 010324
  44. GRB010222, CXO X-ray observations
  45. GRB010324, optical observations
  46. GRB010326B: Localization by HETE (2nd GRB for this date)
  47. GRB 010326 optical observations
  48. GRB010326: Refined Localization by HETE
  49. GRB010326: Localization by HETE
  50. Optical Observations of GRB 010324
  51. GRB990705, VLT-FORS1 observations of the host galaxy
  52. GRB010222, late-time optical observation
  53. Support extension to the BeppoSAX mission
  54. GRB 010222, Optical Observations
  55. GRB010220 optical obsercations
  56. GRB 010222: High-Resolution Keck Spectroscopy
  57. GRB 010214, I-band data
  58. GRB 010222
  59. GRB010222 further R-band photometry
  60. GRB 010222: Keck Spectroscopy
  61. GRB010214, field photometry
  62. GRB010222, field photometry
  63. GRB010222 further R-band photometry
  64. GRB 010222 Kyoto optical observation
  65. GRB010222 R-BAND OBSERVATION
  66. GRB 010220: Near-IR Observations
  67. GRB010214 follow-up from Hanle
  68. GRB 010222: Near-IR Observations
  69. GRB 010222: Optical Observations
  70. GRB010222, radio observations
  71. GRB010222, optical observations
  72. Redshift of the Optical Transient of GRB010222
  73. GRB010220, Radio and Optical Observations
  74. GRB 010220, simultaneous optical observations
  75. GRB010220: BeppoSAX WFC and GRBM preliminary data
  76. GRB010214, candidate optical afterglow
  77. GRB010214, optical observations
  78. GRB010214: BeppoSAX WFC and GRBM preliminary data
  79. GRB 010214: X-Ray afterglow
  80. GRB 010214 optical observation
  81. J-Band Observation of GRB 010214.
  82. GRB010213, Near-IR observations
  83. Possible InfraRed Transient of GRB 010214.
  84. GRB 010214, optical observations
  85. GRB010213 detected by HETE
  86. GRB010214 refined WFC position
  87. IPN Status Report
  88. HETE Status
  89. IPN/RXTE TRIANGULATION OF GRB010126
  90. GRB010126, TNG R-band observations
  91. IPN TRIANGULATION OF GRB010126
  92. Optical Observations of GRB 001018 at Keck
  93. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  94. Optical observations of GRB 001018 with JCAM
  95. IPN TRIANGULATION OF GRB010115
  96. IPN TRIANGULATION OF GRB010109
  97. IPN TRIANGULATION OF GRB010109
  98. IPN triangulation of GRB010104
  99. IPN triangulation of GRB010103
  100. IPN triangulation of GRB001219

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