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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. IPN localization of GRB991105
  2. GRB 991106 Optical Observations
  3. GRB 991105, optical observations
  4. GRB991106, optical observation at SAO-RAS
  5. GRB 991106, LOTIS Optical Observations
  6. GRB 991106, optical observations
  7. BeppoSAX refined position for GRB991106
  8. BeppoSAX GRB Alert: GRB991106
  9. Revised BeppoSAX WFC position of GRB991105
  10. GRB991105: SAX-GRBM/-WFC detection
  11. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  12. GRB ALERT: GRB991105
  13. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  14. GRB 991014, Optical Observations
  15. GRB 991014 - BeppoSAX NFI observations
  16. GRB 991014, Optical Observations
  17. GRB 991014, radio observations
  18. GRB991014 BATSE Observations
  19. GRB 991014, Optical Observations
  20. GRB 991014, optical observations
  21. Super-LOTIS optical observation of GRB991014
  22. IPN/NFI error box for GRB991014
  23. IPN localization of GRB991014 - CORRECTION
  24. IPN localization of GRB991014
  25. BeppoSAX ALERT: GRB991014
  26. GRB 990915 optical observations
  27. GRB 990907 optical observations
  28. BATSE GRB trigger criteria
  29. Optical Observations of GRB990907
  30. IPN error box for GRB990915 (=BATSE 7766)
  31. IPN localization of BATSE #7766 (GRB990915)
  32. GRB990907: BeppoSAX follow up and X-ray afterglow
  33. GRB990907 and 990908
  34. IPN localization of GRB990907
  35. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  36. GRB990907: refined WFC position
  37. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  38. GRB 990712 Late Optical Decay and Host Galaxy
  39. GRB 990712, Optical Observation
  40. GRB990806 BeppoSAX follow up
  41. GRB990806: BATSE Observations
  42. GRB 990806 Optical observations
  43. Optical Observations of GRB990806
  44. GRB 990806, Optical Observations
  45. GRB 990806, optical observations
  46. GRB 990806, Optical Observations
  47. GRB990806 UBVRIJHK observations
  48. GRB990806: possible X-ray afterglow, BeppoSAX
  49. BeppoSAX ALERT GRB990806: Summer GRB
  50. GRB 990712 Optical Observations
  51. GRB990705: No Evidence for Neutrino Signal
  52. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  53. VLT spectrum of GRB990712
  54. GRB 990712
  55. Late-time HST/STIS Observations of GRB 990510
  56. Refined BeppoSAX-WFC position of GRB990712
  57. BeppoSAX NFI Observation of GRB990705
  58. BeppoSAX NFI Observation of GRB990705
  59. Updated Astrometry for the IR Counterpart of GRB990705
  60. GRB 990705, R-band observations
  61. Updated IPN localization of GRB990705
  62. IPN localization of GRB990704
  63. IPN localization of GRB990705
  64. Infrared and Optical Observations of GRB990705
  65. GRB 990705, radio observations
  66. GRB990704: SAX-NFI results summary
  67. GRB990704 radio and optical observations
  68. BeppoSAX GRB990705: possible X-ray afterglow
  69. GRB 990704 X-ray Observations
  70. GRB 990704 Optical Observations
  71. GRB 990704, optical observations
  72. GRB990704
  73. GRB990705: Intriguing Positional Coincidences
  74. GRB990704
  75. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  76. GRB990704, optical observations
  77. GRB990704: possible X-ray afterglow
  78. Identification of a possible optical counterpart for GRB990704
  79. GRB990704
  80. Refined BeppoSAX-WFC position of GRB990704
  81. GRB990704: BeppoSAX detection
  82. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  83. Optical Observations of GRB990627
  84. GRB 990627, radio observations
  85. GRB990627: BeppoSAX-WFC final location
  86. BeppoSAX: GRB990625
  87. Late-time HST/STIS Observation of GRB 990123
  88. GRB 990506 - clarification to GCN 352
  89. GRB 990506 - Optical Observations
  90. Optical Observations of GRB 990506
  91. GRB 990506 Radio Transient
  92. GRB990527 Optical Observations
  93. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  94. IPN error box for GRB990527
  95. Late Afterglows of GRBs 990510, 990123
  96. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  97. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  98. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  99. GRB 990506 optical observation
  100. X-ray/GRB 1SAX J0835.9+5118, Optical Observation

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