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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"

41602 results found.

  1. GRB010222, radio observations
  2. GRB010222, optical observations
  3. GRB010222: BeppoSAX/NFI Observations
  4. Redshift of the Optical Transient of GRB010222
  5. GRB010214B,Gamma Ray Observations
  6. GRB010222: possible optical counterpart
  7. GRB010222
  8. GRB010222
  9. GRB010222: BeppoSAX refined position
  10. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  11. GRB010220, Radio and Optical Observations
  12. GRB 010220, simultaneous optical observations
  13. GRB010220: BeppoSAX WFC and GRBM preliminary data
  14. GRB010214, candidate optical afterglow
  15. GRB010214, optical observations
  16. BeppoSAX ALERT: GRB010220
  17. GRB010214: BeppoSAX WFC and GRBM preliminary data
  18. GRB 010214: X-Ray afterglow
  19. GRB 010214, Optical Observations
  20. GRB010213, Radio Observations
  21. GRB010213 Optical Observation
  22. GRB010213, Radio Observations
  23. J-Band Observation of GRB 010214.
  24. GRB010214, Radio Observations
  25. GRB010214, optical observations
  26. GRB010213, optical observations
  27. GRB010213, Near-IR observations
  28. Possible InfraRed Transient of GRB 010214.
  29. GRB010214 Optical Observation
  30. GRB010214: BeppoSAX/NFI Observations
  31. GRB010213 (HETE) TAROT observations
  32. GRB 010214, optical observations
  33. GRB010213 detected by HETE
  34. BeppoSAX ALERT: GRB010214
  35. IPN Status Report
  36. HETE Status
  37. GRB010126 opt. obs.
  38. IPN/RXTE TRIANGULATION OF GRB010126
  39. GRB010126: CONCAM crude optical limits during GRB
  40. GRB010126, TNG R-band observations
  41. GRB010126 Optical Observations
  42. GRB010126 optical observations
  43. GRB010126: Optical observations
  44. IPN TRIANGULATION OF GRB010126
  45. IPN/RXTE TRIANGULATION OF GRB010126
  46. GRB 010119, optical observations
  47. GRB010119: Optical observations
  48. Optical Observations of GRB 001018 at Keck
  49. GRB010119, Radio observations
  50. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  51. Optical observations of GRB 001018 with JCAM
  52. IPN TRIANGULATION OF GRB010115
  53. IPN TRIANGULATION OF GRB010109
  54. IPN TRIANGULATION OF GRB010109
  55. GRB010103, optical observations
  56. IPN triangulation of GRB010104
  57. IPN triangulation of GRB010103
  58. GRB 001204: Ks observations
  59. H band observation of GRB 001212
  60. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  61. IPN triangulation of GRB001219
  62. GRB 001212 Optical Observation
  63. GRB 001212 Optical Observation
  64. GRB 001212 possible OA in 2MASS
  65. GRB 001212 possible OA
  66. IPN triangulation of GRB001212
  67. GRB001204: Optical observations
  68. GRB001204, Radio observations
  69. IPN triangulation of GRB001204 (short/hard)
  70. GRB 001105, further optical observations
  71. GRB001120: Gunn-i observations
  72. GRB001120: Optical observations
  73. GRB001109, optical observations
  74. GRB001120, optical observations
  75. WSRT 4.8 GHz observations of GRB001109
  76. IPN triangulation of GRB001120
  77. Optical/NIR observations of GRB001109
  78. GRB 001109: deep JHK upper limits
  79. GRB 001109 X-ray afterglow with BeppoSAX
  80. CORRECTION to XMM-Newton observation of GRB001025
  81. GRB001109: Optical observations
  82. GRB001109: BeppoSAX/NFI Observations
  83. GRB001109, R-band optical observations
  84. GRB001109, Radio observations
  85. BeppoSAX ALERT: GRB001109
  86. GRB001105 BVRI field photometry correction
  87. GRB001105, BVRI field photometry
  88. GRB 001105, R-band observation
  89. IPN TRIANGULATION OF GRB001105
  90. GRB 001025B, Optical obervations
  91. GRB 991208: HST Imaging of the Host Galaxy
  92. GRB000926: R-image of the host galaxy
  93. GRB 001025B, I-band observations
  94. XMM-Newton observation of GRB001025
  95. GRB001025B, Radio observations
  96. GRB 001025 Optical Observations
  97. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  98. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  99. IPN triangulation of GRB001025
  100. GRB001007: Optical observations

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