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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. GRB 010222: Optical Observations
  2. GRB 010222, Decay Slope Confirmed
  3. GRB010222: Another absorption line system
  4. GRB010222: Optical decay slope
  5. GRB 010214, Optical Observations
  6. GRB010222: Sub-millimeter detection
  7. GRB010222: R-band fading behavior
  8. GRB010222: Optical Observations
  9. GRB010222, radio observations
  10. GRB010222, optical observations
  11. GRB010222: BeppoSAX/NFI Observations
  12. Redshift of the Optical Transient of GRB010222
  13. GRB010214B,Gamma Ray Observations
  14. GRB010222: possible optical counterpart
  15. GRB010222
  16. GRB010222
  17. GRB010222: BeppoSAX refined position
  18. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  19. GRB010220, Radio and Optical Observations
  20. GRB 010220, simultaneous optical observations
  21. GRB010220: BeppoSAX WFC and GRBM preliminary data
  22. GRB010214, candidate optical afterglow
  23. GRB010214, optical observations
  24. BeppoSAX GRB010220: refined position
  25. BeppoSAX ALERT: GRB010220
  26. GRB010214: BeppoSAX WFC and GRBM preliminary data
  27. GRB 010214: X-Ray afterglow
  28. GRB 010214, Optical Observations
  29. GRB 010214 optical observation
  30. GRB010213, Radio Observations
  31. GRB010213 Optical Observation
  32. GRB010213, Radio Observations
  33. J-Band Observation of GRB 010214.
  34. GRB010214, Radio Observations
  35. GRB010214, optical observations
  36. GRB010213, optical observations
  37. GRB010213, Near-IR observations
  38. Possible InfraRed Transient of GRB 010214.
  39. GRB010214 Optical Observation
  40. GRB010214: BeppoSAX/NFI Observations
  41. GRB010213 (HETE) TAROT observations
  42. GRB 010214, optical observations
  43. GRB010213 detected by HETE
  44. GRB010214 refined WFC position
  45. BeppoSAX ALERT: GRB010214
  46. IPN Status Report
  47. HETE Status
  48. GRB010126 opt. obs.
  49. IPN/RXTE TRIANGULATION OF GRB010126
  50. GRB010126: CONCAM crude optical limits during GRB
  51. GRB010126, TNG R-band observations
  52. GRB010126 Optical Observations
  53. GRB010126 optical observations
  54. GRB010126: Optical observations
  55. IPN TRIANGULATION OF GRB010126
  56. IPN/RXTE TRIANGULATION OF GRB010126
  57. GRB 010119, optical observations
  58. GRB010119: Optical observations
  59. Optical Observations of GRB 001018 at Keck
  60. GRB010119, Radio observations
  61. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  62. Optical observations of GRB 001018 with JCAM
  63. IPN TRIANGULATION OF GRB010115
  64. IPN TRIANGULATION OF GRB010109
  65. IPN TRIANGULATION OF GRB010109
  66. GRB010103, optical observations
  67. IPN triangulation of GRB010104
  68. IPN triangulation of GRB010103
  69. GRB 001204: Ks observations
  70. H band observation of GRB 001212
  71. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  72. IPN triangulation of GRB001219
  73. GRB 001212 Optical Observation
  74. GRB 001212 Optical Observation
  75. GRB 001212 optical observation
  76. GRB 001212 possible OA in 2MASS
  77. GRB 001212 possible OA
  78. IPN triangulation of GRB001212
  79. GRB001204: Optical observations
  80. Confirmation of IPN position for GRB001204
  81. GRB001204, Radio observations
  82. IPN triangulation of GRB001204 (short/hard)
  83. GRB 001105, further optical observations
  84. GRB001120: Gunn-i observations
  85. GRB001120: Optical observations
  86. GRB001109, optical observations
  87. GRB001120, optical observations
  88. WSRT 4.8 GHz observations of GRB001109
  89. IPN triangulation of GRB001120
  90. Optical/NIR observations of GRB001109
  91. GRB 001109: deep JHK upper limits
  92. GRB 001109 X-ray afterglow with BeppoSAX
  93. CORRECTION to XMM-Newton observation of GRB001025
  94. GRB001109: Optical observations
  95. GRB001109: BeppoSAX/NFI Observations
  96. GRB001109, R-band optical observations
  97. GRB001109, Radio observations
  98. GRB001109: BeppoSAX refined WFC position
  99. BeppoSAX ALERT: GRB001109
  100. GRB001105 BVRI field photometry correction

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