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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"

44952 results found.

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

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