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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"

44339 results found.

  1. GRB000210, Radio Observations
  2. Optical candidate for GRB000210
  3. Chandra Observations of GRB000210 X-ray Afterglow
  4. IPN triangulation of GRB000210
  5. GRB000210: possible afterglow detection with BeppoSAX NFI
  6. GRB000201, Radio Observations
  7. GRB000210: BeppoSAX GRBM and WFC Detection
  8. Optical observations of GRB000131
  9. GRB000201 Optical Observations
  10. GRB 000201: TAROT optical observations
  11. GRB 000131 Optical Observations
  12. GRB000126 Optical Observations
  13. GRB 991208, radio observations
  14. BATSE+IPN location of GRB000131
  15. IPN localization of GRB000131
  16. GRB 000126, optical observations
  17. GRB000126, optical observations
  18. BATSE location of GRB000126
  19. IPN localization of GRB000126
  20. GRB 000115 Optical observations
  21. BATSE Observations of GRB000115
  22. Correction to GCN 520 (IPN annulus for GRB000115)
  23. Second RXTE Observation of GRB 000115
  24. GRB991216, UBVRIJHK field photometry
  25. GRB991216 late optical observation
  26. Single IPN error box for GRB991229
  27. GCN resumes full operations
  28. GRB 991216 VLBA Observations
  29. BEPPOSAX GRBM Localization of GRB991226
  30. IPN error boxes for GRB991229
  31. GRB 991216: J band spectrophotometry
  32. GRB 991216: Detection of the Host and/or Absorber Galaxy
  33. IPN localization of GRB991226
  34. Single IPN error box for GRB991221
  35. IPN error boxes for GRB991221
  36. GRB 991216 RXTE ASM Observations
  37. IPN error box for GRB991216
  38. GRB 991216: Updated BATSE parameters
  39. Lowell/Perkins observation of GRB 991216
  40. GRB 991217 (SAX J2303.2+0015) Optical observations
  41. GRB991217/SAX J2303.2+0015, optical observations
  42. Chandra observation of the X-ray afterglow of GRB991216
  43. GRB 991216, optical observations
  44. GRB 991216 Optical Observations
  45. GRB 991216 Optical spectroscopy/imaging
  46. VLT spectra of GRB991216
  47. GRB991216 Optical and IR observations
  48. K observations of GRB991216
  49. SAX J2303.2+0015 Optical observations
  50. IR observations of GRB991216
  51. GRB991216 radio observations
  52. GRB991216 radio observations
  53. GRB991216 Spectroscopy
  54. Lowell/Perkins observation of GRB 991216
  55. GRB991216, optical observations
  56. GRB991216 Optical and infrared observations of Beethoven Burst
  57. Refined IPN localization of GRB991216
  58. GRB 991216 Radio Observations
  59. GRB 991217
  60. GRB 991208 Keck Spectroscopy
  61. GRB 991208 Infrared Detection
  62. GRB991216
  63. GRB 991216--Summary of RXTE Observations
  64. GRB 991216 Optical Observations
  65. GRB 991216, optical observations
  66. GRB 991208 SAO-RAS Spectroscopy
  67. SAX J2303.2+0015: an x-ray/GRB?
  68. GRB 991216, Optical Transient
  69. GRB 991216, Optical Afterglow
  70. GRB991216 ('Beethoven Burst') B, R, and K Observations
  71. GRB 991216: Comparison with DPOSS images
  72. GRB991216, infrared observations
  73. GRB991216 Optical Observations
  74. GRB 991208 optical observations
  75. Lowell/Perkins observation of GRB 991216
  76. GRB 991216 Optical Observation
  77. GRB 991208 Keck Spectroscopy
  78. GRB 991216: Extremely bright BATSE burst
  79. R-band Observations of GRB991208 at TNG
  80. GRB991208, optical observations
  81. GRB 991208 Keck Spectroscopy
  82. GRB991208 - millimeter detection
  83. GRB 991208, Optical Observation
  84. GRB991208 15-GHz observations
  85. GRB991208, optical observations
  86. GRB 991208 - OVRO detection
  87. GRB 991208 Optical Decay
  88. GRB 991208 optical observations
  89. GRB 991208 optical observations
  90. GRB 991208: Radio Observations
  91. IPN localization of GRB991208
  92. Optical Observations of GRB991105
  93. GRB991106: BeppoSAX/BATSE results
  94. GRB 991106, optical observations
  95. GRB991106, near-infrared observations
  96. BeppoSAX NFI Observation of GRB991106
  97. GRB 991106, radio observations
  98. GRB991106: the first BeppoSAX short GRB detection?
  99. GRB 991105: BATSE Observations
  100. IPN localization of GRB991105

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