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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"

32494 results found.

  1. Chandra Observations of GRB000210 X-ray Afterglow
  2. IPN triangulation of GRB000210
  3. GRB000201, Radio Observations
  4. Optical observations of GRB000131
  5. GRB000201 Optical Observations
  6. GRB 000131 Optical Observations
  7. GRB000126 Optical Observations
  8. GRB 991208, radio observations
  9. BATSE+IPN location of GRB000131
  10. GRB 000126, optical observations
  11. GRB000126, optical observations
  12. BATSE location of GRB000126
  13. GRB 000115 Optical observations
  14. BATSE Observations of GRB000115
  15. Correction to GCN 520 (IPN annulus for GRB000115)
  16. IPN annulus for GRB000115
  17. GRB991216, UBVRIJHK field photometry
  18. GRB991216 late optical observation
  19. Single IPN error box for GRB991229
  20. GCN resumes full operations
  21. GRB 991216 VLBA Observations
  22. BEPPOSAX GRBM Localization of GRB991226
  23. GRB 991216: J band spectrophotometry
  24. GRB 991216: Detection of the Host and/or Absorber Galaxy
  25. Single IPN error box for GRB991221
  26. GRB 991216 RXTE ASM Observations
  27. IPN error box for GRB991216
  28. Lowell/Perkins observation of GRB 991216
  29. GRB 991217 (SAX J2303.2+0015) Optical observations
  30. GRB991217/SAX J2303.2+0015, optical observations
  31. Chandra observation of the X-ray afterglow of GRB991216
  32. GRB 991216, optical observations
  33. GRB 991216 Optical Observations
  34. GRB 991216 Optical spectroscopy/imaging
  35. VLT spectra of GRB991216
  36. GRB991216 Optical and IR observations
  37. SAX J2303.2+0015 Optical observations
  38. IR observations of GRB991216
  39. GRB991216 radio observations
  40. GRB 991217 (SAX J2303.2+0015) Optical observations
  41. GRB991216 radio observations
  42. Lowell/Perkins observation of GRB 991216
  43. GRB991216, optical observations
  44. Refined IPN localization of GRB991216
  45. GRB 991216 Radio Observations
  46. GRB 991208 Keck Spectroscopy
  47. GRB 991208 Infrared Detection
  48. GRB991216
  49. GRB 991216--Summary of RXTE Observations
  50. GRB 991216 Optical Observations
  51. GRB 991216, optical observations
  52. GRB 991208 SAO-RAS Spectroscopy
  53. GRB 991216, Optical Transient
  54. GRB 991216, Optical Afterglow
  55. GRB991216 ('Beethoven Burst') B, R, and K Observations
  56. GRB 991216: Comparison with DPOSS images
  57. GRB 991208 optical observations
  58. Lowell/Perkins observation of GRB 991216
  59. GRB 991216 Optical Observation
  60. GRB 991208 Keck Spectroscopy
  61. R-band Observations of GRB991208 at TNG
  62. GRB991208, optical observations
  63. GRB 991208 Keck Spectroscopy
  64. GRB991208 - millimeter detection
  65. GRB 991208, Optical Observation
  66. GRB991208 15-GHz observations
  67. GRB991208, optical observations
  68. GRB 991208 - OVRO detection
  69. GRB 991208 Optical Decay
  70. GRB 991208 optical observations
  71. GRB 991208 optical observations
  72. GRB 991208: Radio Observations
  73. Optical Observations of GRB991105
  74. GRB991106: BeppoSAX/BATSE results
  75. GRB 991106, optical observations
  76. GRB991106, near-infrared observations
  77. BeppoSAX NFI Observation of GRB991106
  78. GRB 991106, radio observations
  79. GRB 991105: BATSE Observations
  80. IPN localization of GRB991105
  81. GRB 991106 Optical Observations
  82. GRB 991105, optical observations
  83. GRB991106, optical observation at SAO-RAS
  84. GRB 991106, LOTIS Optical Observations
  85. GRB 991106, optical observations
  86. Revised BeppoSAX WFC position of GRB991105
  87. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  88. GRB 991014, Optical Observations
  89. GRB 991014 - BeppoSAX NFI observations
  90. GRB 991014, Optical Observations
  91. GRB 991014, Optical Observations
  92. GRB 991014, optical observations
  93. Super-LOTIS optical observation of GRB991014
  94. IPN/NFI error box for GRB991014
  95. IPN localization of GRB991014 - CORRECTION
  96. IPN localization of GRB991014
  97. GRB 990915 optical observations
  98. GRB 990907 optical observations
  99. Optical Observations of GRB990907
  100. IPN error box for GRB990915 (=BATSE 7766)

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