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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"

36144 results found.

  1. Optical observations of the Chandra X-ray source for GRB000210
  2. Chandra Observations of GRB000210 X-ray Afterglow
  3. IPN triangulation of GRB000210
  4. GRB 000201: TAROT optical observations
  5. GRB 000131 Optical Observations
  6. GRB000126 Optical Observations
  7. BATSE GRB trigger criteria changed
  8. GRB 991208, radio observations
  9. BATSE+IPN location of GRB000131
  10. IPN localization of GRB000131
  11. GRB 000126, optical observations
  12. GRB000126, optical observations
  13. BATSE location of GRB000126
  14. IPN localization of GRB000126
  15. GRB 000115 Optical observations
  16. BATSE Observations of GRB000115
  17. Second RXTE Observation of GRB 000115
  18. GRB991216, UBVRIJHK field photometry
  19. Single IPN error box for GRB991229
  20. GCN resumes full operations
  21. GRB 991216 VLBA Observations
  22. BEPPOSAX GRBM Localization of GRB991226
  23. IPN error boxes for GRB991229
  24. GRB 991216: J band spectrophotometry
  25. GRB 991216: Detection of the Host and/or Absorber Galaxy
  26. IPN localization of GRB991226
  27. Single IPN error box for GRB991221
  28. IPN error boxes for GRB991221
  29. GRB 991216 RXTE ASM Observations
  30. IPN error box for GRB991216
  31. GRB 991216: Updated BATSE parameters
  32. Lowell/Perkins observation of GRB 991216
  33. GRB 991217 (SAX J2303.2+0015) Optical observations
  34. Chandra observation of the X-ray afterglow of GRB991216
  35. GRB 991216, optical observations
  36. GRB 991216 Optical Observations
  37. GRB 991216 Optical spectroscopy/imaging
  38. K observations of GRB991216
  39. GRB 991217 (SAX J2303.2+0015) Optical observations
  40. GRB991216 Spectroscopy
  41. Lowell/Perkins observation of GRB 991216
  42. GRB991216, optical observations
  43. Refined IPN localization of GRB991216
  44. GRB 991216 Radio Observations
  45. GRB 991217
  46. GRB 991208 Keck Spectroscopy
  47. GRB 991208 Infrared Detection
  48. GRB 991216--Summary of RXTE Observations
  49. GRB 991216 Optical Observations
  50. GRB 991216, optical observations
  51. GRB 991208 SAO-RAS Spectroscopy
  52. SAX J2303.2+0015: an x-ray/GRB?
  53. GRB 991216, Optical Transient
  54. GRB 991216, Optical Afterglow
  55. GRB 991216: Comparison with DPOSS images
  56. GRB 991208 optical observations
  57. Lowell/Perkins observation of GRB 991216
  58. GRB 991216 Optical Observation
  59. GRB 991208 Keck Spectroscopy
  60. GRB 991216: Extremely bright BATSE burst
  61. GRB991208, optical observations
  62. GRB 991208 Keck Spectroscopy
  63. GRB991208 - millimeter detection
  64. GRB 991208, Optical Observation
  65. GRB 991208 - OVRO detection
  66. GRB 991208 Optical Decay
  67. GRB 991208 optical observations
  68. GRB 991208 optical observations
  69. GRB 991208: Radio Observations
  70. IPN localization of GRB991208
  71. Optical Observations of GRB991105
  72. GRB991106: BeppoSAX/BATSE results
  73. GRB 991106, optical observations
  74. GRB991106, near-infrared observations
  75. BeppoSAX NFI Observation of GRB991106
  76. GRB 991106, radio observations
  77. GRB991106: the first BeppoSAX short GRB detection?
  78. GRB 991105: BATSE Observations
  79. IPN localization of GRB991105
  80. GRB 991106 Optical Observations
  81. GRB 991105, optical observations
  82. GRB991106, optical observation at SAO-RAS
  83. GRB 991106, LOTIS Optical Observations
  84. GRB 991106, optical observations
  85. BeppoSAX GRB Alert: GRB991106
  86. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  87. GRB ALERT: GRB991105
  88. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  89. GRB 991014, Optical Observations
  90. GRB 991014 - BeppoSAX NFI observations
  91. GRB 991014, Optical Observations
  92. GRB 991014, radio observations
  93. GRB991014 BATSE Observations
  94. GRB 991014, Optical Observations
  95. GRB 991014, optical observations
  96. Super-LOTIS optical observation of GRB991014
  97. IPN/NFI error box for GRB991014
  98. IPN localization of GRB991014 - CORRECTION
  99. IPN localization of GRB991014
  100. BeppoSAX ALERT: GRB991014

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