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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. SAX_WFC_GRB_NOTICE
  2. Optical observations of GRB000131
  3. GRB000201 Optical Observations
  4. GRB 000201: TAROT optical observations
  5. GRB 000131 Optical Observations
  6. GRB000126 Optical Observations
  7. BATSE GRB trigger criteria changed
  8. GRB 991208, radio observations
  9. BATSE+IPN location of GRB000131
  10. IPN localization of GRB000131
  11. GRB 000126, optical observations
  12. GRB000126, optical observations
  13. BATSE location of GRB000126
  14. IPN localization of GRB000126
  15. GRB 000115 Optical observations
  16. BATSE Observations of GRB000115
  17. Correction to GCN 520 (IPN annulus for GRB000115)
  18. IPN annulus for GRB000115
  19. Second RXTE Observation of GRB 000115
  20. GRB991216, UBVRIJHK field photometry
  21. GRB991216 late optical observation
  22. Single IPN error box for GRB991229
  23. GCN resumes full operations
  24. GRB 991216 VLBA Observations
  25. BEPPOSAX GRBM Localization of GRB991226
  26. IPN error boxes for GRB991229
  27. GRB 991216: J band spectrophotometry
  28. GRB 991216: Detection of the Host and/or Absorber Galaxy
  29. IPN localization of GRB991226
  30. Single IPN error box for GRB991221
  31. IPN error boxes for GRB991221
  32. GRB 991216 RXTE ASM Observations
  33. IPN error box for GRB991216
  34. GRB 991216: Updated BATSE parameters
  35. Lowell/Perkins observation of GRB 991216
  36. GRB 991217 (SAX J2303.2+0015) Optical observations
  37. GRB991217/SAX J2303.2+0015, optical observations
  38. Chandra observation of the X-ray afterglow of GRB991216
  39. GRB 991216, optical observations
  40. GRB 991216 Optical Observations
  41. GRB 991216 Optical spectroscopy/imaging
  42. VLT spectra of GRB991216
  43. GRB991216 Optical and IR observations
  44. K observations of GRB991216
  45. SAX J2303.2+0015 Optical observations
  46. IR observations of GRB991216
  47. GRB991216 radio observations
  48. GRB 991217 (SAX J2303.2+0015) Optical observations
  49. GRB991216 radio observations
  50. GRB991216 Spectroscopy
  51. Lowell/Perkins observation of GRB 991216
  52. GRB991216, optical observations
  53. GRB991216 Optical and infrared observations of Beethoven Burst
  54. Refined IPN localization of GRB991216
  55. GRB 991216 Radio Observations
  56. GRB 991217
  57. GRB 991208 Keck Spectroscopy
  58. GRB 991208 Infrared Detection
  59. GRB991216
  60. GRB 991216--Summary of RXTE Observations
  61. GRB 991216 Optical Observations
  62. GRB 991216, optical observations
  63. GRB 991208 SAO-RAS Spectroscopy
  64. SAX J2303.2+0015: an x-ray/GRB?
  65. GRB 991216, Optical Transient
  66. GRB 991216, Optical Afterglow
  67. GRB991216 ('Beethoven Burst') B, R, and K Observations
  68. GRB 991216: Comparison with DPOSS images
  69. GRB991216, infrared observations
  70. GRB991216 Optical Observations
  71. GRB 991208 optical observations
  72. Lowell/Perkins observation of GRB 991216
  73. GRB 991216 Optical Observation
  74. GRB 991208 Keck Spectroscopy
  75. GRB 991216: Extremely bright BATSE burst
  76. R-band Observations of GRB991208 at TNG
  77. GRB991208, optical observations
  78. GRB 991208 Keck Spectroscopy
  79. GRB991208 - millimeter detection
  80. GRB 991208, Optical Observation
  81. GRB991208 15-GHz observations
  82. GRB991208, optical observations
  83. GRB 991208 - OVRO detection
  84. GRB 991208 Optical Decay
  85. GRB 991208 optical observations
  86. GRB 991208 optical observations
  87. GRB 991208: Radio Observations
  88. IPN localization of GRB991208
  89. Optical Observations of GRB991105
  90. GRB991106: BeppoSAX/BATSE results
  91. GRB 991106, optical observations
  92. GRB991106, near-infrared observations
  93. BeppoSAX NFI Observation of GRB991106
  94. GRB 991106, radio observations
  95. GRB991106: the first BeppoSAX short GRB detection?
  96. GRB 991105: BATSE Observations
  97. IPN localization of GRB991105
  98. GRB 991106 Optical Observations
  99. GRB 991105, optical observations
  100. GRB991106, optical observation at SAO-RAS

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