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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. Single IPN error box for GRB991229
  2. GCN resumes full operations
  3. GRB 991216 VLBA Observations
  4. BEPPOSAX GRBM Localization of GRB991226
  5. IPN error boxes for GRB991229
  6. GRB 991216: J band spectrophotometry
  7. GRB 991216: Detection of the Host and/or Absorber Galaxy
  8. IPN localization of GRB991226
  9. Single IPN error box for GRB991221
  10. IPN error boxes for GRB991221
  11. GRB 991216 RXTE ASM Observations
  12. IPN error box for GRB991216
  13. GRB 991216: Updated BATSE parameters
  14. Lowell/Perkins observation of GRB 991216
  15. GRB 991217 (SAX J2303.2+0015) Optical observations
  16. GRB991217/SAX J2303.2+0015, optical observations
  17. Chandra observation of the X-ray afterglow of GRB991216
  18. GRB 991216, optical observations
  19. GRB 991216 Optical Observations
  20. GRB 991216 Optical spectroscopy/imaging
  21. VLT spectra of GRB991216
  22. GRB991216 Optical and IR observations
  23. K observations of GRB991216
  24. SAX J2303.2+0015 Optical observations
  25. IR observations of GRB991216
  26. GRB991216 radio observations
  27. GRB 991217 (SAX J2303.2+0015) Optical observations
  28. GRB991216 radio observations
  29. GRB991216 Spectroscopy
  30. Lowell/Perkins observation of GRB 991216
  31. GRB991216, optical observations
  32. GRB991216 Optical and infrared observations of Beethoven Burst
  33. Refined IPN localization of GRB991216
  34. GRB 991216 Radio Observations
  35. GRB 991217
  36. GRB 991208 Keck Spectroscopy
  37. GRB 991208 Infrared Detection
  38. GRB991216
  39. GRB 991216--Summary of RXTE Observations
  40. GRB 991216 Optical Observations
  41. GRB 991216, optical observations
  42. GRB 991208 SAO-RAS Spectroscopy
  43. SAX J2303.2+0015: an x-ray/GRB?
  44. GRB 991216, Optical Transient
  45. GRB 991216, Optical Afterglow
  46. GRB991216 ('Beethoven Burst') B, R, and K Observations
  47. GRB 991216: Comparison with DPOSS images
  48. GRB991216, infrared observations
  49. GRB991216 Optical Observations
  50. GRB 991208 optical observations
  51. Lowell/Perkins observation of GRB 991216
  52. GRB 991216 Optical Observation
  53. GRB 991208 Keck Spectroscopy
  54. GRB 991216: Extremely bright BATSE burst
  55. R-band Observations of GRB991208 at TNG
  56. GRB991208, optical observations
  57. GRB 991208 Keck Spectroscopy
  58. GRB991208 - millimeter detection
  59. GRB 991208, Optical Observation
  60. GRB991208 15-GHz observations
  61. GRB991208, optical observations
  62. GRB 991208 - OVRO detection
  63. GRB 991208 Optical Decay
  64. GRB 991208 optical observations
  65. GRB 991208 optical observations
  66. GRB 991208: Radio Observations
  67. IPN localization of GRB991208
  68. Optical Observations of GRB991105
  69. GRB991106: BeppoSAX/BATSE results
  70. GRB 991106, optical observations
  71. GRB991106, near-infrared observations
  72. BeppoSAX NFI Observation of GRB991106
  73. GRB 991106, radio observations
  74. GRB991106: the first BeppoSAX short GRB detection?
  75. GRB 991105: BATSE Observations
  76. IPN localization of GRB991105
  77. GRB 991106 Optical Observations
  78. GRB 991105, optical observations
  79. GRB991106, optical observation at SAO-RAS
  80. GRB 991106, LOTIS Optical Observations
  81. GRB 991106, optical observations
  82. BeppoSAX refined position for GRB991106
  83. BeppoSAX GRB Alert: GRB991106
  84. Revised BeppoSAX WFC position of GRB991105
  85. GRB991105: SAX-GRBM/-WFC detection
  86. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  87. GRB ALERT: GRB991105
  88. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  89. GRB 991014, Optical Observations
  90. GRB 991014 - BeppoSAX NFI observations
  91. GRB 991014, Optical Observations
  92. GRB 991014, radio observations
  93. GRB991014 BATSE Observations
  94. GRB 991014, Optical Observations
  95. GRB 991014, optical observations
  96. Super-LOTIS optical observation of GRB991014
  97. IPN/NFI error box for GRB991014
  98. IPN localization of GRB991014 - CORRECTION
  99. IPN localization of GRB991014
  100. BeppoSAX ALERT: GRB991014

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