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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').
  1. GRB010220, Radio and Optical Observations
  2. GRB 010220, simultaneous optical observations
  3. GRB010220: BeppoSAX WFC and GRBM preliminary data
  4. GRB010214, candidate optical afterglow
  5. GRB010214, optical observations
  6. BeppoSAX GRB010220: refined position
  7. BeppoSAX ALERT: GRB010220
  8. GRB010214: BeppoSAX WFC and GRBM preliminary data
  9. GRB 010214: X-Ray afterglow
  10. GRB 010214, Optical Observations
  11. GRB 010214 optical observation
  12. GRB010213, Radio Observations
  13. GRB010213 Optical Observation
  14. GRB010213, Radio Observations
  15. J-Band Observation of GRB 010214.
  16. GRB010214, Radio Observations
  17. GRB010214, optical observations
  18. GRB010213, optical observations
  19. GRB010213, Near-IR observations
  20. Possible InfraRed Transient of GRB 010214.
  21. GRB010214 Optical Observation
  22. GRB010214: BeppoSAX/NFI Observations
  23. GRB010213 (HETE) TAROT observations
  24. GRB 010214, optical observations
  25. GRB010213 detected by HETE
  26. GRB010214 refined WFC position
  27. BeppoSAX ALERT: GRB010214
  28. IPN Status Report
  29. HETE Status
  30. GRB010126 opt. obs.
  31. IPN/RXTE TRIANGULATION OF GRB010126
  32. GRB010126: CONCAM crude optical limits during GRB
  33. GRB010126, TNG R-band observations
  34. GRB010126 Optical Observations
  35. GRB010126 optical observations
  36. GRB010126: Optical observations
  37. IPN TRIANGULATION OF GRB010126
  38. IPN/RXTE TRIANGULATION OF GRB010126
  39. GRB 010119, optical observations
  40. GRB010119: Optical observations
  41. Optical Observations of GRB 001018 at Keck
  42. GRB010119, Radio observations
  43. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  44. Optical observations of GRB 001018 with JCAM
  45. IPN TRIANGULATION OF GRB010115
  46. IPN TRIANGULATION OF GRB010109
  47. IPN TRIANGULATION OF GRB010109
  48. GRB010103, optical observations
  49. IPN triangulation of GRB010104
  50. IPN triangulation of GRB010103
  51. GRB 001204: Ks observations
  52. H band observation of GRB 001212
  53. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  54. IPN triangulation of GRB001219
  55. GRB 001212 Optical Observation
  56. GRB 001212 Optical Observation
  57. GRB 001212 optical observation
  58. GRB 001212 possible OA in 2MASS
  59. GRB 001212 possible OA
  60. IPN triangulation of GRB001212
  61. GRB001204: Optical observations
  62. Confirmation of IPN position for GRB001204
  63. GRB001204, Radio observations
  64. IPN triangulation of GRB001204 (short/hard)
  65. GRB 001105, further optical observations
  66. GRB001120: Gunn-i observations
  67. GRB001120: Optical observations
  68. GRB001109, optical observations
  69. GRB001120, optical observations
  70. WSRT 4.8 GHz observations of GRB001109
  71. IPN triangulation of GRB001120
  72. Optical/NIR observations of GRB001109
  73. GRB 001109: deep JHK upper limits
  74. GRB 001109 X-ray afterglow with BeppoSAX
  75. CORRECTION to XMM-Newton observation of GRB001025
  76. GRB001109: Optical observations
  77. GRB001109: BeppoSAX/NFI Observations
  78. GRB001109, R-band optical observations
  79. GRB001109, Radio observations
  80. GRB001109: BeppoSAX refined WFC position
  81. BeppoSAX ALERT: GRB001109
  82. GRB001105 BVRI field photometry correction
  83. GRB001105, BVRI field photometry
  84. GRB 001105, R-band observation
  85. IPN TRIANGULATION OF GRB001105
  86. GRB 001025B, Optical obervations
  87. GRB 991208: HST Imaging of the Host Galaxy
  88. GRB000926: R-image of the host galaxy
  89. GRB 001025B, I-band observations
  90. XMM-Newton observation of GRB001025
  91. GRB001025B, Radio observations
  92. GRB 001025 Optical Observations
  93. GRB 001025A, optical observation
  94. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  95. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  96. IPN triangulation of GRB001025
  97. GRB001007: Optical observations
  98. ASM Localization of GRB 001025
  99. GRB001007, Radio observations
  100. IPN TRIANGULATION OF GRB001020

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