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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"

43619 results found.

  1. GRB010222: Optical Observations
  2. GRB010222, radio observations
  3. GRB010222, optical observations
  4. GRB010222: BeppoSAX/NFI Observations
  5. Redshift of the Optical Transient of GRB010222
  6. GRB010214B,Gamma Ray Observations
  7. GRB010222: possible optical counterpart
  8. GRB010222
  9. GRB010222
  10. GRB010222: BeppoSAX refined position
  11. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  12. GRB010220, Radio and Optical Observations
  13. GRB 010220, simultaneous optical observations
  14. GRB010220: BeppoSAX WFC and GRBM preliminary data
  15. GRB010214, candidate optical afterglow
  16. GRB010214, optical observations
  17. BeppoSAX GRB010220: refined position
  18. BeppoSAX ALERT: GRB010220
  19. GRB010214: BeppoSAX WFC and GRBM preliminary data
  20. GRB 010214: X-Ray afterglow
  21. GRB 010214, Optical Observations
  22. GRB010213, Radio Observations
  23. GRB010213 Optical Observation
  24. GRB010213, Radio Observations
  25. J-Band Observation of GRB 010214.
  26. GRB010214, Radio Observations
  27. GRB010214, optical observations
  28. GRB010213, optical observations
  29. GRB010213, Near-IR observations
  30. Possible InfraRed Transient of GRB 010214.
  31. GRB010214 Optical Observation
  32. GRB010214: BeppoSAX/NFI Observations
  33. GRB010213 (HETE) TAROT observations
  34. GRB 010214, optical observations
  35. GRB010213 detected by HETE
  36. GRB010214 refined WFC position
  37. BeppoSAX ALERT: GRB010214
  38. IPN Status Report
  39. HETE Status
  40. GRB010126 opt. obs.
  41. IPN/RXTE TRIANGULATION OF GRB010126
  42. GRB010126: CONCAM crude optical limits during GRB
  43. GRB010126, TNG R-band observations
  44. GRB010126 Optical Observations
  45. GRB010126 optical observations
  46. GRB010126: Optical observations
  47. IPN TRIANGULATION OF GRB010126
  48. IPN/RXTE TRIANGULATION OF GRB010126
  49. GRB 010119, optical observations
  50. GRB010119: Optical observations
  51. Optical Observations of GRB 001018 at Keck
  52. GRB010119, Radio observations
  53. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  54. Optical observations of GRB 001018 with JCAM
  55. IPN TRIANGULATION OF GRB010115
  56. IPN TRIANGULATION OF GRB010109
  57. IPN TRIANGULATION OF GRB010109
  58. GRB010103, optical observations
  59. IPN triangulation of GRB010104
  60. IPN triangulation of GRB010103
  61. GRB 001204: Ks observations
  62. H band observation of GRB 001212
  63. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  64. IPN triangulation of GRB001219
  65. GRB 001212 Optical Observation
  66. GRB 001212 Optical Observation
  67. GRB 001212 possible OA in 2MASS
  68. GRB 001212 possible OA
  69. IPN triangulation of GRB001212
  70. GRB001204: Optical observations
  71. GRB001204, Radio observations
  72. IPN triangulation of GRB001204 (short/hard)
  73. GRB 001105, further optical observations
  74. GRB001120: Gunn-i observations
  75. GRB001120: Optical observations
  76. GRB001109, optical observations
  77. GRB001120, optical observations
  78. WSRT 4.8 GHz observations of GRB001109
  79. IPN triangulation of GRB001120
  80. Optical/NIR observations of GRB001109
  81. GRB 001109: deep JHK upper limits
  82. GRB 001109 X-ray afterglow with BeppoSAX
  83. CORRECTION to XMM-Newton observation of GRB001025
  84. GRB001109: Optical observations
  85. GRB001109: BeppoSAX/NFI Observations
  86. GRB001109, R-band optical observations
  87. GRB001109, Radio observations
  88. GRB001109: BeppoSAX refined WFC position
  89. BeppoSAX ALERT: GRB001109
  90. GRB001105 BVRI field photometry correction
  91. GRB001105, BVRI field photometry
  92. GRB 001105, R-band observation
  93. IPN TRIANGULATION OF GRB001105
  94. GRB 001025B, Optical obervations
  95. GRB 991208: HST Imaging of the Host Galaxy
  96. GRB000926: R-image of the host galaxy
  97. GRB 001025B, I-band observations
  98. XMM-Newton observation of GRB001025
  99. GRB001025B, Radio observations
  100. GRB 001025 Optical Observations

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