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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. GRB 000301C: OT confirmed
  2. GRB000301c optical observations
  3. GRB 000301A, Radio Observations
  4. GRB000301C, optical observations
  5. GRB000301c, near-infrared observations
  6. GRB000301C
  7. GRB 000301C : Optical Candidate
  8. Radio observations of the error box of GRB000301A
  9. GRB000301C: RXTE/ASM and IPN localizations
  10. GRB000301A [IPN Position]
  11. GRB000226 [IPN Position]
  12. HST Observations of GRB 990712
  13. GRB 000214 near-IR observations
  14. GRB 000115 Optical observations
  15. GRB 000214, Radio Observations
  16. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  17. GRB000210, Radio Observations
  18. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  19. GRB 000115, BVRI field photometry
  20. GRB000214: BeppoSAX GRBM and WFC Detection
  21. IPN annulus for GRB000214
  22. BATSE GRB trigger criterion changed
  23. Optical observations of GRB000210
  24. GRB000210 X-ray afterglow
  25. GRB000214: X-ray afterglow candidate
  26. GRB000214 refined BeppoSAX-WFC position
  27. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  28. GRB 000210: BATSE Observations
  29. Correction to Chandra Position of GRB000210 afterglow
  30. Optical observations of the Chandra X-ray source for GRB000210
  31. GRB000210, Radio Observations
  32. Optical candidate for GRB000210
  33. Chandra Observations of GRB000210 X-ray Afterglow
  34. IPN triangulation of GRB000210
  35. GRB000210: possible afterglow detection with BeppoSAX NFI
  36. GRB000201, Radio Observations
  37. GRB000210: BeppoSAX GRBM and WFC Detection
  38. SAX_WFC_GRB_NOTICE
  39. SAX_WFC_GRB_NOTICE
  40. Optical observations of GRB000131
  41. GRB000201 Optical Observations
  42. GRB 000201: TAROT optical observations
  43. GRB 000131 Optical Observations
  44. GRB000126 Optical Observations
  45. BATSE GRB trigger criteria changed
  46. GRB 991208, radio observations
  47. BATSE+IPN location of GRB000131
  48. IPN localization of GRB000131
  49. GRB 000126, optical observations
  50. GRB000126, optical observations
  51. BATSE location of GRB000126
  52. IPN localization of GRB000126
  53. GRB 000115 Optical observations
  54. BATSE Observations of GRB000115
  55. Correction to GCN 520 (IPN annulus for GRB000115)
  56. IPN annulus for GRB000115
  57. Second RXTE Observation of GRB 000115
  58. GRB991216, UBVRIJHK field photometry
  59. GRB991216 late optical observation
  60. Single IPN error box for GRB991229
  61. GCN resumes full operations
  62. GRB 991216 VLBA Observations
  63. BEPPOSAX GRBM Localization of GRB991226
  64. IPN error boxes for GRB991229
  65. GRB 991216: J band spectrophotometry
  66. GRB 991216: Detection of the Host and/or Absorber Galaxy
  67. IPN localization of GRB991226
  68. Single IPN error box for GRB991221
  69. IPN error boxes for GRB991221
  70. GRB 991216 RXTE ASM Observations
  71. IPN error box for GRB991216
  72. GRB 991216: Updated BATSE parameters
  73. Lowell/Perkins observation of GRB 991216
  74. GRB 991217 (SAX J2303.2+0015) Optical observations
  75. GRB991217/SAX J2303.2+0015, optical observations
  76. Chandra observation of the X-ray afterglow of GRB991216
  77. GRB 991216, optical observations
  78. GRB 991216 Optical Observations
  79. GRB 991216 Optical spectroscopy/imaging
  80. VLT spectra of GRB991216
  81. GRB991216 Optical and IR observations
  82. K observations of GRB991216
  83. SAX J2303.2+0015 Optical observations
  84. IR observations of GRB991216
  85. GRB991216 radio observations
  86. GRB 991217 (SAX J2303.2+0015) Optical observations
  87. GRB991216 radio observations
  88. GRB991216 Spectroscopy
  89. Lowell/Perkins observation of GRB 991216
  90. GRB991216, optical observations
  91. GRB991216 Optical and infrared observations of Beethoven Burst
  92. Refined IPN localization of GRB991216
  93. GRB 991216 Radio Observations
  94. GRB 991217
  95. GRB 991208 Keck Spectroscopy
  96. GRB 991208 Infrared Detection
  97. GRB991216
  98. GRB 991216--Summary of RXTE Observations
  99. GRB 991216 Optical Observations
  100. GRB 991216, optical observations

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