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

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