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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. GRB000210, Radio Observations
  2. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  3. GRB 000115, BVRI field photometry
  4. GRB000214: BeppoSAX GRBM and WFC Detection
  5. IPN annulus for GRB000214
  6. BATSE GRB trigger criterion changed
  7. Optical observations of GRB000210
  8. GRB000210 X-ray afterglow
  9. GRB000214: X-ray afterglow candidate
  10. GRB000214 refined BeppoSAX-WFC position
  11. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  12. GRB 000210: BATSE Observations
  13. Correction to Chandra Position of GRB000210 afterglow
  14. Optical observations of the Chandra X-ray source for GRB000210
  15. GRB000210, Radio Observations
  16. Optical candidate for GRB000210
  17. Chandra Observations of GRB000210 X-ray Afterglow
  18. IPN triangulation of GRB000210
  19. GRB000210: possible afterglow detection with BeppoSAX NFI
  20. GRB000201, Radio Observations
  21. GRB000210: BeppoSAX GRBM and WFC Detection
  22. SAX_WFC_GRB_NOTICE
  23. SAX_WFC_GRB_NOTICE
  24. Optical observations of GRB000131
  25. GRB000201 Optical Observations
  26. GRB 000201: TAROT optical observations
  27. GRB 000131 Optical Observations
  28. GRB000126 Optical Observations
  29. BATSE GRB trigger criteria changed
  30. GRB 991208, radio observations
  31. BATSE+IPN location of GRB000131
  32. IPN localization of GRB000131
  33. GRB 000126, optical observations
  34. GRB000126, optical observations
  35. BATSE location of GRB000126
  36. IPN localization of GRB000126
  37. GRB 000115 Optical observations
  38. BATSE Observations of GRB000115
  39. Correction to GCN 520 (IPN annulus for GRB000115)
  40. IPN annulus for GRB000115
  41. Second RXTE Observation of GRB 000115
  42. GRB991216, UBVRIJHK field photometry
  43. GRB991216 late optical observation
  44. Single IPN error box for GRB991229
  45. GCN resumes full operations
  46. GRB 991216 VLBA Observations
  47. BEPPOSAX GRBM Localization of GRB991226
  48. IPN error boxes for GRB991229
  49. GRB 991216: J band spectrophotometry
  50. GRB 991216: Detection of the Host and/or Absorber Galaxy
  51. IPN localization of GRB991226
  52. Single IPN error box for GRB991221
  53. IPN error boxes for GRB991221
  54. GRB 991216 RXTE ASM Observations
  55. IPN error box for GRB991216
  56. GRB 991216: Updated BATSE parameters
  57. Lowell/Perkins observation of GRB 991216
  58. GRB 991217 (SAX J2303.2+0015) Optical observations
  59. GRB991217/SAX J2303.2+0015, optical observations
  60. Chandra observation of the X-ray afterglow of GRB991216
  61. GRB 991216, optical observations
  62. GRB 991216 Optical Observations
  63. GRB 991216 Optical spectroscopy/imaging
  64. VLT spectra of GRB991216
  65. GRB991216 Optical and IR observations
  66. K observations of GRB991216
  67. SAX J2303.2+0015 Optical observations
  68. IR observations of GRB991216
  69. GRB991216 radio observations
  70. GRB 991217 (SAX J2303.2+0015) Optical observations
  71. GRB991216 radio observations
  72. GRB991216 Spectroscopy
  73. Lowell/Perkins observation of GRB 991216
  74. GRB991216, optical observations
  75. GRB991216 Optical and infrared observations of Beethoven Burst
  76. Refined IPN localization of GRB991216
  77. GRB 991216 Radio Observations
  78. GRB 991217
  79. GRB 991208 Keck Spectroscopy
  80. GRB 991208 Infrared Detection
  81. GRB991216
  82. GRB 991216--Summary of RXTE Observations
  83. GRB 991216 Optical Observations
  84. GRB 991216, optical observations
  85. GRB 991208 SAO-RAS Spectroscopy
  86. SAX J2303.2+0015: an x-ray/GRB?
  87. GRB 991216, Optical Transient
  88. GRB 991216, Optical Afterglow
  89. GRB991216 ('Beethoven Burst') B, R, and K Observations
  90. GRB 991216: Comparison with DPOSS images
  91. GRB991216, infrared observations
  92. GRB991216 Optical Observations
  93. GRB 991208 optical observations
  94. Lowell/Perkins observation of GRB 991216
  95. GRB 991216 Optical Observation
  96. GRB 991208 Keck Spectroscopy
  97. GRB 991216: Extremely bright BATSE burst
  98. R-band Observations of GRB991208 at TNG
  99. GRB991208, optical observations
  100. GRB 991208 Keck Spectroscopy

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