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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"

36140 results found.

  1. GRB 000131 Optical Observations
  2. GRB000126 Optical Observations
  3. BATSE GRB trigger criteria changed
  4. GRB 991208, radio observations
  5. BATSE+IPN location of GRB000131
  6. IPN localization of GRB000131
  7. GRB 000126, optical observations
  8. GRB000126, optical observations
  9. BATSE location of GRB000126
  10. IPN localization of GRB000126
  11. GRB 000115 Optical observations
  12. BATSE Observations of GRB000115
  13. Second RXTE Observation of GRB 000115
  14. GRB991216, UBVRIJHK field photometry
  15. Single IPN error box for GRB991229
  16. GCN resumes full operations
  17. GRB 991216 VLBA Observations
  18. BEPPOSAX GRBM Localization of GRB991226
  19. IPN error boxes for GRB991229
  20. GRB 991216: J band spectrophotometry
  21. GRB 991216: Detection of the Host and/or Absorber Galaxy
  22. IPN localization of GRB991226
  23. Single IPN error box for GRB991221
  24. IPN error boxes for GRB991221
  25. GRB 991216 RXTE ASM Observations
  26. IPN error box for GRB991216
  27. GRB 991216: Updated BATSE parameters
  28. Lowell/Perkins observation of GRB 991216
  29. GRB 991217 (SAX J2303.2+0015) Optical observations
  30. Chandra observation of the X-ray afterglow of GRB991216
  31. GRB 991216, optical observations
  32. GRB 991216 Optical Observations
  33. GRB 991216 Optical spectroscopy/imaging
  34. K observations of GRB991216
  35. GRB 991217 (SAX J2303.2+0015) Optical observations
  36. GRB991216 Spectroscopy
  37. Lowell/Perkins observation of GRB 991216
  38. GRB991216, optical observations
  39. Refined IPN localization of GRB991216
  40. GRB 991216 Radio Observations
  41. GRB 991217
  42. GRB 991208 Keck Spectroscopy
  43. GRB 991208 Infrared Detection
  44. GRB 991216--Summary of RXTE Observations
  45. GRB 991216 Optical Observations
  46. GRB 991216, optical observations
  47. GRB 991208 SAO-RAS Spectroscopy
  48. SAX J2303.2+0015: an x-ray/GRB?
  49. GRB 991216, Optical Transient
  50. GRB 991216, Optical Afterglow
  51. GRB 991216: Comparison with DPOSS images
  52. GRB 991208 optical observations
  53. Lowell/Perkins observation of GRB 991216
  54. GRB 991216 Optical Observation
  55. GRB 991208 Keck Spectroscopy
  56. GRB 991216: Extremely bright BATSE burst
  57. GRB991208, optical observations
  58. GRB 991208 Keck Spectroscopy
  59. GRB991208 - millimeter detection
  60. GRB 991208, Optical Observation
  61. GRB 991208 - OVRO detection
  62. GRB 991208 Optical Decay
  63. GRB 991208 optical observations
  64. GRB 991208 optical observations
  65. GRB 991208: Radio Observations
  66. IPN localization of GRB991208
  67. Optical Observations of GRB991105
  68. GRB991106: BeppoSAX/BATSE results
  69. GRB 991106, optical observations
  70. GRB991106, near-infrared observations
  71. BeppoSAX NFI Observation of GRB991106
  72. GRB 991106, radio observations
  73. GRB991106: the first BeppoSAX short GRB detection?
  74. GRB 991105: BATSE Observations
  75. IPN localization of GRB991105
  76. GRB 991106 Optical Observations
  77. GRB 991105, optical observations
  78. GRB991106, optical observation at SAO-RAS
  79. GRB 991106, LOTIS Optical Observations
  80. GRB 991106, optical observations
  81. BeppoSAX GRB Alert: GRB991106
  82. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  83. GRB ALERT: GRB991105
  84. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  85. GRB 991014, Optical Observations
  86. GRB 991014 - BeppoSAX NFI observations
  87. GRB 991014, Optical Observations
  88. GRB 991014, radio observations
  89. GRB991014 BATSE Observations
  90. GRB 991014, Optical Observations
  91. GRB 991014, optical observations
  92. Super-LOTIS optical observation of GRB991014
  93. IPN/NFI error box for GRB991014
  94. IPN localization of GRB991014 - CORRECTION
  95. IPN localization of GRB991014
  96. BeppoSAX ALERT: GRB991014
  97. GRB 990915 optical observations
  98. GRB 990907 optical observations
  99. BATSE GRB trigger criteria
  100. Optical Observations of GRB990907

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