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

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