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

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