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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: Optical observation and decay
  2. GRB 010214, I-band data
  3. Sub-millimeter Excess/GRB 010222
  4. GRB 010222
  5. GRB 010222 HST/Chandra TOO
  6. GRB 010222
  7. GRB010222 further R-band photometry
  8. GRB010222: R-band data
  9. GRB010222 Optical observations
  10. GRB 010222: Keck Spectroscopy
  11. GRB010214, field photometry
  12. GRB010222, field photometry
  13. GRB010222 further R-band photometry
  14. GRB010222, possible increase of optical decay slope
  15. GRB 010222 Kyoto optical observation
  16. GRB010222: fading behavior
  17. GRB 010222 BV optical observations
  18. GRB010220, Optical Observations
  19. GRB010222 R-BAND OBSERVATION
  20. GRB 010220: Near-IR Observations
  21. GRB010214 follow-up from Hanle
  22. GRB 010222: Near-IR Observations
  23. GRB 010222: Optical Observations
  24. GRB 010222, Decay Slope Confirmed
  25. GRB010222: Another absorption line system
  26. GRB010222: Optical decay slope
  27. GRB 010214, Optical Observations
  28. GRB010222: Sub-millimeter detection
  29. GRB010222: R-band fading behavior
  30. GRB010222: Optical Observations
  31. GRB010222, radio observations
  32. GRB010222, optical observations
  33. GRB010222: BeppoSAX/NFI Observations
  34. Redshift of the Optical Transient of GRB010222
  35. GRB010214B,Gamma Ray Observations
  36. GRB010222: possible optical counterpart
  37. GRB010222
  38. GRB010222
  39. GRB010222: BeppoSAX refined position
  40. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  41. GRB010220, Radio and Optical Observations
  42. GRB 010220, simultaneous optical observations
  43. GRB010220: BeppoSAX WFC and GRBM preliminary data
  44. GRB010214, candidate optical afterglow
  45. GRB010214, optical observations
  46. BeppoSAX GRB010220: refined position
  47. BeppoSAX ALERT: GRB010220
  48. GRB010214: BeppoSAX WFC and GRBM preliminary data
  49. GRB 010214: X-Ray afterglow
  50. GRB 010214, Optical Observations
  51. GRB 010214 optical observation
  52. GRB010213, Radio Observations
  53. GRB010213 Optical Observation
  54. GRB010213, Radio Observations
  55. J-Band Observation of GRB 010214.
  56. GRB010214, Radio Observations
  57. GRB010214, optical observations
  58. GRB010213, optical observations
  59. GRB010213, Near-IR observations
  60. Possible InfraRed Transient of GRB 010214.
  61. GRB010214 Optical Observation
  62. GRB010214: BeppoSAX/NFI Observations
  63. GRB010213 (HETE) TAROT observations
  64. GRB 010214, optical observations
  65. GRB010213 detected by HETE
  66. GRB010214 refined WFC position
  67. BeppoSAX ALERT: GRB010214
  68. IPN Status Report
  69. HETE Status
  70. GRB010126 opt. obs.
  71. IPN/RXTE TRIANGULATION OF GRB010126
  72. GRB010126: CONCAM crude optical limits during GRB
  73. GRB010126, TNG R-band observations
  74. GRB010126 Optical Observations
  75. GRB010126 optical observations
  76. GRB010126: Optical observations
  77. IPN TRIANGULATION OF GRB010126
  78. IPN/RXTE TRIANGULATION OF GRB010126
  79. GRB 010119, optical observations
  80. GRB010119: Optical observations
  81. Optical Observations of GRB 001018 at Keck
  82. GRB010119, Radio observations
  83. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  84. Optical observations of GRB 001018 with JCAM
  85. IPN TRIANGULATION OF GRB010115
  86. IPN TRIANGULATION OF GRB010109
  87. IPN TRIANGULATION OF GRB010109
  88. GRB010103, optical observations
  89. IPN triangulation of GRB010104
  90. IPN triangulation of GRB010103
  91. GRB 001204: Ks observations
  92. H band observation of GRB 001212
  93. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  94. IPN triangulation of GRB001219
  95. GRB 001212 Optical Observation
  96. GRB 001212 Optical Observation
  97. GRB 001212 optical observation
  98. GRB 001212 possible OA in 2MASS
  99. GRB 001212 possible OA
  100. IPN triangulation of GRB001212

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