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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"
  1. GRB ALERT: GRB991105
  2. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  3. GRB 991014, Optical Observations
  4. GRB 991014 - BeppoSAX NFI observations
  5. GRB 991014, Optical Observations
  6. GRB 991014, radio observations
  7. GRB991014 BATSE Observations
  8. GRB 991014, Optical Observations
  9. GRB 991014, optical observations
  10. Super-LOTIS optical observation of GRB991014
  11. IPN/NFI error box for GRB991014
  12. IPN localization of GRB991014 - CORRECTION
  13. IPN localization of GRB991014
  14. BeppoSAX ALERT: GRB991014
  15. GRB 990915 optical observations
  16. GRB 990907 optical observations
  17. BATSE GRB trigger criteria
  18. Optical Observations of GRB990907
  19. IPN error box for GRB990915 (=BATSE 7766)
  20. IPN localization of BATSE #7766 (GRB990915)
  21. GRB990907: BeppoSAX follow up and X-ray afterglow
  22. GRB990907 and 990908
  23. IPN localization of GRB990907
  24. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  25. GRB990907: refined WFC position
  26. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  27. GRB 990712 Late Optical Decay and Host Galaxy
  28. GRB 990712, Optical Observation
  29. GRB990806 BeppoSAX follow up
  30. GRB990806: BATSE Observations
  31. GRB 990806 Optical observations
  32. Optical Observations of GRB990806
  33. GRB 990806, Optical Observations
  34. GRB 990806, optical observations
  35. GRB 990806, Optical Observations
  36. GRB990806 UBVRIJHK observations
  37. GRB990806: possible X-ray afterglow, BeppoSAX
  38. BeppoSAX ALERT GRB990806: Summer GRB
  39. GRB 990712 Optical Observations
  40. GRB990705: No Evidence for Neutrino Signal
  41. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  42. VLT spectrum of GRB990712
  43. GRB 990712
  44. Late-time HST/STIS Observations of GRB 990510
  45. Refined BeppoSAX-WFC position of GRB990712
  46. BeppoSAX NFI Observation of GRB990705
  47. BeppoSAX NFI Observation of GRB990705
  48. Updated Astrometry for the IR Counterpart of GRB990705
  49. GRB 990705, R-band observations
  50. Updated IPN localization of GRB990705
  51. IPN localization of GRB990704
  52. IPN localization of GRB990705
  53. Infrared and Optical Observations of GRB990705
  54. GRB 990705, radio observations
  55. GRB990704: SAX-NFI results summary
  56. GRB990704 radio and optical observations
  57. BeppoSAX GRB990705: possible X-ray afterglow
  58. GRB 990704 X-ray Observations
  59. GRB 990704 Optical Observations
  60. GRB 990704, optical observations
  61. GRB990704
  62. GRB990705: Intriguing Positional Coincidences
  63. GRB990704
  64. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  65. GRB990704, optical observations
  66. GRB990704: possible X-ray afterglow
  67. Identification of a possible optical counterpart for GRB990704
  68. GRB990704
  69. Refined BeppoSAX-WFC position of GRB990704
  70. GRB990704: BeppoSAX detection
  71. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  72. Optical Observations of GRB990627
  73. GRB 990627, radio observations
  74. GRB990627: BeppoSAX-WFC final location
  75. BeppoSAX: GRB990625
  76. Late-time HST/STIS Observation of GRB 990123
  77. GRB 990506 - clarification to GCN 352
  78. GRB 990506 - Optical Observations
  79. Optical Observations of GRB 990506
  80. GRB 990506 Radio Transient
  81. GRB990527 Optical Observations
  82. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  83. IPN error box for GRB990527
  84. Late Afterglows of GRBs 990510, 990123
  85. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  86. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  87. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  88. GRB 990506 optical observation
  89. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  90. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  91. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  92. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  93. radio observations of X-ray/GRB transient field
  94. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  95. Optical report on X-ray/GRB transient
  96. radio detection of X-ray/GRB transient
  97. BeppoSAX: A new fast X-ray transient
  98. GRB 990510: optical observations
  99. GRB990510: photometric and spectroscopic observations with the VLT
  100. GRB 990510: optical linear polarization

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