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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 annulus for GRB000214
  2. BATSE GRB trigger criterion changed
  3. Optical observations of GRB000210
  4. GRB000210 X-ray afterglow
  5. GRB000214: X-ray afterglow candidate
  6. GRB000214 refined BeppoSAX-WFC position
  7. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  8. GRB 000210: BATSE Observations
  9. Correction to Chandra Position of GRB000210 afterglow
  10. Optical observations of the Chandra X-ray source for GRB000210
  11. GRB000210, Radio Observations
  12. Optical candidate for GRB000210
  13. Chandra Observations of GRB000210 X-ray Afterglow
  14. IPN triangulation of GRB000210
  15. GRB000210: possible afterglow detection with BeppoSAX NFI
  16. GRB000201, Radio Observations
  17. GRB000210: BeppoSAX GRBM and WFC Detection
  18. SAX_WFC_GRB_NOTICE
  19. SAX_WFC_GRB_NOTICE
  20. Optical observations of GRB000131
  21. GRB000201 Optical Observations
  22. GRB 000201: TAROT optical observations
  23. GRB 000131 Optical Observations
  24. GRB000126 Optical Observations
  25. BATSE GRB trigger criteria changed
  26. GRB 991208, radio observations
  27. BATSE+IPN location of GRB000131
  28. IPN localization of GRB000131
  29. GRB 000126, optical observations
  30. GRB000126, optical observations
  31. BATSE location of GRB000126
  32. IPN localization of GRB000126
  33. GRB 000115 Optical observations
  34. BATSE Observations of GRB000115
  35. Correction to GCN 520 (IPN annulus for GRB000115)
  36. IPN annulus for GRB000115
  37. Second RXTE Observation of GRB 000115
  38. GRB991216, UBVRIJHK field photometry
  39. GRB991216 late optical observation
  40. Single IPN error box for GRB991229
  41. GCN resumes full operations
  42. GRB 991216 VLBA Observations
  43. BEPPOSAX GRBM Localization of GRB991226
  44. IPN error boxes for GRB991229
  45. GRB 991216: J band spectrophotometry
  46. GRB 991216: Detection of the Host and/or Absorber Galaxy
  47. IPN localization of GRB991226
  48. Single IPN error box for GRB991221
  49. IPN error boxes for GRB991221
  50. GRB 991216 RXTE ASM Observations
  51. IPN error box for GRB991216
  52. GRB 991216: Updated BATSE parameters
  53. Lowell/Perkins observation of GRB 991216
  54. GRB 991217 (SAX J2303.2+0015) Optical observations
  55. GRB991217/SAX J2303.2+0015, optical observations
  56. Chandra observation of the X-ray afterglow of GRB991216
  57. GRB 991216, optical observations
  58. GRB 991216 Optical Observations
  59. GRB 991216 Optical spectroscopy/imaging
  60. VLT spectra of GRB991216
  61. GRB991216 Optical and IR observations
  62. K observations of GRB991216
  63. SAX J2303.2+0015 Optical observations
  64. IR observations of GRB991216
  65. GRB991216 radio observations
  66. GRB 991217 (SAX J2303.2+0015) Optical observations
  67. GRB991216 radio observations
  68. GRB991216 Spectroscopy
  69. Lowell/Perkins observation of GRB 991216
  70. GRB991216, optical observations
  71. GRB991216 Optical and infrared observations of Beethoven Burst
  72. Refined IPN localization of GRB991216
  73. GRB 991216 Radio Observations
  74. GRB 991217
  75. GRB 991208 Keck Spectroscopy
  76. GRB 991208 Infrared Detection
  77. GRB991216
  78. GRB 991216--Summary of RXTE Observations
  79. GRB 991216 Optical Observations
  80. GRB 991216, optical observations
  81. GRB 991208 SAO-RAS Spectroscopy
  82. SAX J2303.2+0015: an x-ray/GRB?
  83. GRB 991216, Optical Transient
  84. GRB 991216, Optical Afterglow
  85. GRB991216 ('Beethoven Burst') B, R, and K Observations
  86. GRB 991216: Comparison with DPOSS images
  87. GRB991216, infrared observations
  88. GRB991216 Optical Observations
  89. GRB 991208 optical observations
  90. Lowell/Perkins observation of GRB 991216
  91. GRB 991216 Optical Observation
  92. GRB 991208 Keck Spectroscopy
  93. GRB 991216: Extremely bright BATSE burst
  94. R-band Observations of GRB991208 at TNG
  95. GRB991208, optical observations
  96. GRB 991208 Keck Spectroscopy
  97. GRB991208 - millimeter detection
  98. GRB 991208, Optical Observation
  99. GRB991208 15-GHz observations
  100. GRB991208, optical observations

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