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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"

42627 results found.

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

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