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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"

32509 results found.

  1. Radio observations of the error box of GRB000301A
  2. HST Observations of GRB 990712
  3. GRB 000115 Optical observations
  4. GRB 000214, Radio Observations
  5. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  6. GRB000210, Radio Observations
  7. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  8. IPN annulus for GRB000214
  9. Optical observations of GRB000210
  10. GRB000210 X-ray afterglow
  11. GRB 000210: BATSE Observations
  12. Correction to Chandra Position of GRB000210 afterglow
  13. Optical observations of the Chandra X-ray source for GRB000210
  14. GRB000210, Radio Observations
  15. Optical candidate for GRB000210
  16. Chandra Observations of GRB000210 X-ray Afterglow
  17. IPN triangulation of GRB000210
  18. GRB000201, Radio Observations
  19. Optical observations of GRB000131
  20. GRB000201 Optical Observations
  21. GRB 000131 Optical Observations
  22. GRB000126 Optical Observations
  23. GRB 991208, radio observations
  24. BATSE+IPN location of GRB000131
  25. GRB 000126, optical observations
  26. GRB000126, optical observations
  27. BATSE location of GRB000126
  28. GRB 000115 Optical observations
  29. BATSE Observations of GRB000115
  30. Correction to GCN 520 (IPN annulus for GRB000115)
  31. IPN annulus for GRB000115
  32. GRB991216, UBVRIJHK field photometry
  33. GRB991216 late optical observation
  34. Single IPN error box for GRB991229
  35. GCN resumes full operations
  36. GRB 991216 VLBA Observations
  37. BEPPOSAX GRBM Localization of GRB991226
  38. GRB 991216: J band spectrophotometry
  39. GRB 991216: Detection of the Host and/or Absorber Galaxy
  40. Single IPN error box for GRB991221
  41. GRB 991216 RXTE ASM Observations
  42. IPN error box for GRB991216
  43. Lowell/Perkins observation of GRB 991216
  44. GRB 991217 (SAX J2303.2+0015) Optical observations
  45. GRB991217/SAX J2303.2+0015, optical observations
  46. Chandra observation of the X-ray afterglow of GRB991216
  47. GRB 991216, optical observations
  48. GRB 991216 Optical Observations
  49. GRB 991216 Optical spectroscopy/imaging
  50. VLT spectra of GRB991216
  51. GRB991216 Optical and IR observations
  52. SAX J2303.2+0015 Optical observations
  53. IR observations of GRB991216
  54. GRB991216 radio observations
  55. GRB 991217 (SAX J2303.2+0015) Optical observations
  56. GRB991216 radio observations
  57. Lowell/Perkins observation of GRB 991216
  58. GRB991216, optical observations
  59. Refined IPN localization of GRB991216
  60. GRB 991216 Radio Observations
  61. GRB 991208 Keck Spectroscopy
  62. GRB 991208 Infrared Detection
  63. GRB991216
  64. GRB 991216--Summary of RXTE Observations
  65. GRB 991216 Optical Observations
  66. GRB 991216, optical observations
  67. GRB 991208 SAO-RAS Spectroscopy
  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. GRB 991208 optical observations
  73. Lowell/Perkins observation of GRB 991216
  74. GRB 991216 Optical Observation
  75. GRB 991208 Keck Spectroscopy
  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. Optical Observations of GRB991105
  89. GRB991106: BeppoSAX/BATSE results
  90. GRB 991106, optical observations
  91. GRB991106, near-infrared observations
  92. BeppoSAX NFI Observation of GRB991106
  93. GRB 991106, radio observations
  94. GRB 991105: BATSE Observations
  95. IPN localization of GRB991105
  96. GRB 991106 Optical Observations
  97. GRB 991105, optical observations
  98. GRB991106, optical observation at SAO-RAS
  99. GRB 991106, LOTIS Optical Observations
  100. GRB 991106, optical observations

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