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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 991216: Detection of the Host and/or Absorber Galaxy
  2. IPN localization of GRB991226
  3. Single IPN error box for GRB991221
  4. IPN error boxes for GRB991221
  5. GRB 991216 RXTE ASM Observations
  6. IPN error box for GRB991216
  7. GRB 991216: Updated BATSE parameters
  8. Lowell/Perkins observation of GRB 991216
  9. GRB 991217 (SAX J2303.2+0015) Optical observations
  10. GRB991217/SAX J2303.2+0015, optical observations
  11. Chandra observation of the X-ray afterglow of GRB991216
  12. GRB 991216, optical observations
  13. GRB 991216 Optical Observations
  14. GRB 991216 Optical spectroscopy/imaging
  15. VLT spectra of GRB991216
  16. GRB991216 Optical and IR observations
  17. K observations of GRB991216
  18. SAX J2303.2+0015 Optical observations
  19. IR observations of GRB991216
  20. GRB991216 radio observations
  21. GRB 991217 (SAX J2303.2+0015) Optical observations
  22. GRB991216 radio observations
  23. GRB991216 Spectroscopy
  24. Lowell/Perkins observation of GRB 991216
  25. GRB991216, optical observations
  26. GRB991216 Optical and infrared observations of Beethoven Burst
  27. Refined IPN localization of GRB991216
  28. GRB 991216 Radio Observations
  29. GRB 991217
  30. GRB 991208 Keck Spectroscopy
  31. GRB 991208 Infrared Detection
  32. GRB991216
  33. GRB 991216--Summary of RXTE Observations
  34. GRB 991216 Optical Observations
  35. GRB 991216, optical observations
  36. GRB 991208 SAO-RAS Spectroscopy
  37. SAX J2303.2+0015: an x-ray/GRB?
  38. GRB 991216, Optical Transient
  39. GRB 991216, Optical Afterglow
  40. GRB991216 ('Beethoven Burst') B, R, and K Observations
  41. GRB 991216: Comparison with DPOSS images
  42. GRB991216, infrared observations
  43. GRB991216 Optical Observations
  44. GRB 991208 optical observations
  45. Lowell/Perkins observation of GRB 991216
  46. GRB 991216 Optical Observation
  47. GRB 991208 Keck Spectroscopy
  48. GRB 991216: Extremely bright BATSE burst
  49. R-band Observations of GRB991208 at TNG
  50. GRB991208, optical observations
  51. GRB 991208 Keck Spectroscopy
  52. GRB991208 - millimeter detection
  53. GRB 991208, Optical Observation
  54. GRB991208 15-GHz observations
  55. GRB991208, optical observations
  56. GRB 991208 - OVRO detection
  57. GRB 991208 Optical Decay
  58. GRB 991208 optical observations
  59. GRB 991208 optical observations
  60. GRB 991208: Radio Observations
  61. IPN localization of GRB991208
  62. Optical Observations of GRB991105
  63. GRB991106: BeppoSAX/BATSE results
  64. GRB 991106, optical observations
  65. GRB991106, near-infrared observations
  66. BeppoSAX NFI Observation of GRB991106
  67. GRB 991106, radio observations
  68. GRB991106: the first BeppoSAX short GRB detection?
  69. GRB 991105: BATSE Observations
  70. IPN localization of GRB991105
  71. GRB 991106 Optical Observations
  72. GRB 991105, optical observations
  73. GRB991106, optical observation at SAO-RAS
  74. GRB 991106, LOTIS Optical Observations
  75. GRB 991106, optical observations
  76. BeppoSAX refined position for GRB991106
  77. BeppoSAX GRB Alert: GRB991106
  78. Revised BeppoSAX WFC position of GRB991105
  79. GRB991105: SAX-GRBM/-WFC detection
  80. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  81. GRB ALERT: GRB991105
  82. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  83. GRB 991014, Optical Observations
  84. GRB 991014 - BeppoSAX NFI observations
  85. GRB 991014, Optical Observations
  86. GRB 991014, radio observations
  87. GRB991014 BATSE Observations
  88. GRB 991014, Optical Observations
  89. GRB 991014, optical observations
  90. Super-LOTIS optical observation of GRB991014
  91. IPN/NFI error box for GRB991014
  92. IPN localization of GRB991014 - CORRECTION
  93. IPN localization of GRB991014
  94. BeppoSAX ALERT: GRB991014
  95. GRB 990915 optical observations
  96. GRB 990907 optical observations
  97. BATSE GRB trigger criteria
  98. Optical Observations of GRB990907
  99. IPN error box for GRB990915 (=BATSE 7766)
  100. IPN localization of BATSE #7766 (GRB990915)

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