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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"
  1. GRB010222: Sub-millimeter vanishing act
  2. GRB010222 - Optical observation
  3. GRB 010222, Optical Observations
  4. GRB010220 optical obsercations
  5. GRB010222 - Optical observation
  6. GRB 010222: High-Resolution Keck Spectroscopy
  7. GRB010222: Optical observation and decay
  8. GRB 010214, I-band data
  9. Sub-millimeter Excess/GRB 010222
  10. GRB 010222
  11. GRB 010222 HST/Chandra TOO
  12. GRB 010222
  13. GRB010222 further R-band photometry
  14. GRB010222: R-band data
  15. GRB010222 Optical observations
  16. GRB 010222: Keck Spectroscopy
  17. GRB010214, field photometry
  18. GRB010222, field photometry
  19. GRB010222 further R-band photometry
  20. GRB010222, possible increase of optical decay slope
  21. GRB 010222 Kyoto optical observation
  22. GRB010222: fading behavior
  23. GRB 010222 BV optical observations
  24. GRB010220, Optical Observations
  25. GRB010222 R-BAND OBSERVATION
  26. GRB 010220: Near-IR Observations
  27. GRB010214 follow-up from Hanle
  28. GRB 010222: Near-IR Observations
  29. GRB 010222: Optical Observations
  30. GRB 010222, Decay Slope Confirmed
  31. GRB010222: Another absorption line system
  32. GRB010222: Optical decay slope
  33. GRB 010214, Optical Observations
  34. GRB010222: Sub-millimeter detection
  35. GRB010222: R-band fading behavior
  36. GRB010222: Optical Observations
  37. GRB010222, radio observations
  38. GRB010222, optical observations
  39. GRB010222: BeppoSAX/NFI Observations
  40. Redshift of the Optical Transient of GRB010222
  41. GRB010214B,Gamma Ray Observations
  42. GRB010222: possible optical counterpart
  43. GRB010222
  44. GRB010222
  45. GRB010222: BeppoSAX refined position
  46. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  47. GRB010220, Radio and Optical Observations
  48. GRB 010220, simultaneous optical observations
  49. GRB010220: BeppoSAX WFC and GRBM preliminary data
  50. GRB010214, candidate optical afterglow
  51. GRB010214, optical observations
  52. BeppoSAX GRB010220: refined position
  53. BeppoSAX ALERT: GRB010220
  54. GRB010214: BeppoSAX WFC and GRBM preliminary data
  55. GRB 010214: X-Ray afterglow
  56. GRB 010214, Optical Observations
  57. GRB 010214 optical observation
  58. GRB010213, Radio Observations
  59. GRB010213 Optical Observation
  60. GRB010213, Radio Observations
  61. J-Band Observation of GRB 010214.
  62. GRB010214, Radio Observations
  63. GRB010214, optical observations
  64. GRB010213, optical observations
  65. GRB010213, Near-IR observations
  66. Possible InfraRed Transient of GRB 010214.
  67. GRB010214 Optical Observation
  68. GRB010214: BeppoSAX/NFI Observations
  69. GRB010213 (HETE) TAROT observations
  70. GRB 010214, optical observations
  71. GRB010213 detected by HETE
  72. GRB010214 refined WFC position
  73. BeppoSAX ALERT: GRB010214
  74. IPN Status Report
  75. HETE Status
  76. GRB010126 opt. obs.
  77. IPN/RXTE TRIANGULATION OF GRB010126
  78. GRB010126: CONCAM crude optical limits during GRB
  79. GRB010126, TNG R-band observations
  80. GRB010126 Optical Observations
  81. GRB010126 optical observations
  82. GRB010126: Optical observations
  83. IPN TRIANGULATION OF GRB010126
  84. IPN/RXTE TRIANGULATION OF GRB010126
  85. GRB 010119, optical observations
  86. GRB010119: Optical observations
  87. Optical Observations of GRB 001018 at Keck
  88. GRB010119, Radio observations
  89. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  90. Optical observations of GRB 001018 with JCAM
  91. IPN TRIANGULATION OF GRB010115
  92. IPN TRIANGULATION OF GRB010109
  93. IPN TRIANGULATION OF GRB010109
  94. GRB010103, optical observations
  95. IPN triangulation of GRB010104
  96. IPN triangulation of GRB010103
  97. GRB 001204: Ks observations
  98. H band observation of GRB 001212
  99. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  100. IPN triangulation of GRB001219

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