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

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