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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. GRB000301C 250 GHz detection
  2. GRB 000301C R-band observation
  3. GRB 000301C, Optical Observation
  4. GRB000301C, near-infrared observations (JHK' photometry)
  5. GRB 000301C: OT confirmed
  6. GRB000301c optical observations
  7. GRB 000301A, Radio Observations
  8. GRB000301C, optical observations
  9. GRB000301c, near-infrared observations
  10. GRB000301C
  11. GRB 000301C : Optical Candidate
  12. Radio observations of the error box of GRB000301A
  13. GRB000301C: RXTE/ASM and IPN localizations
  14. GRB000301A [IPN Position]
  15. GRB000226 [IPN Position]
  16. HST Observations of GRB 990712
  17. GRB 000214 near-IR observations
  18. GRB 000115 Optical observations
  19. GRB 000214, Radio Observations
  20. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  21. GRB000210, Radio Observations
  22. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  23. GRB 000115, BVRI field photometry
  24. GRB000214: BeppoSAX GRBM and WFC Detection
  25. IPN annulus for GRB000214
  26. BATSE GRB trigger criterion changed
  27. Optical observations of GRB000210
  28. GRB000210 X-ray afterglow
  29. GRB000214: X-ray afterglow candidate
  30. GRB000214 refined BeppoSAX-WFC position
  31. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  32. GRB 000210: BATSE Observations
  33. Correction to Chandra Position of GRB000210 afterglow
  34. Optical observations of the Chandra X-ray source for GRB000210
  35. GRB000210, Radio Observations
  36. Optical candidate for GRB000210
  37. Chandra Observations of GRB000210 X-ray Afterglow
  38. IPN triangulation of GRB000210
  39. GRB000210: possible afterglow detection with BeppoSAX NFI
  40. GRB000201, Radio Observations
  41. GRB000210: BeppoSAX GRBM and WFC Detection
  42. SAX_WFC_GRB_NOTICE
  43. SAX_WFC_GRB_NOTICE
  44. Optical observations of GRB000131
  45. GRB000201 Optical Observations
  46. GRB 000201: TAROT optical observations
  47. GRB 000131 Optical Observations
  48. GRB000126 Optical Observations
  49. BATSE GRB trigger criteria changed
  50. GRB 991208, radio observations
  51. BATSE+IPN location of GRB000131
  52. IPN localization of GRB000131
  53. GRB 000126, optical observations
  54. GRB000126, optical observations
  55. BATSE location of GRB000126
  56. IPN localization of GRB000126
  57. GRB 000115 Optical observations
  58. BATSE Observations of GRB000115
  59. Correction to GCN 520 (IPN annulus for GRB000115)
  60. IPN annulus for GRB000115
  61. Second RXTE Observation of GRB 000115
  62. GRB991216, UBVRIJHK field photometry
  63. GRB991216 late optical observation
  64. Single IPN error box for GRB991229
  65. GCN resumes full operations
  66. GRB 991216 VLBA Observations
  67. BEPPOSAX GRBM Localization of GRB991226
  68. IPN error boxes for GRB991229
  69. GRB 991216: J band spectrophotometry
  70. GRB 991216: Detection of the Host and/or Absorber Galaxy
  71. IPN localization of GRB991226
  72. Single IPN error box for GRB991221
  73. IPN error boxes for GRB991221
  74. GRB 991216 RXTE ASM Observations
  75. IPN error box for GRB991216
  76. GRB 991216: Updated BATSE parameters
  77. Lowell/Perkins observation of GRB 991216
  78. GRB 991217 (SAX J2303.2+0015) Optical observations
  79. GRB991217/SAX J2303.2+0015, optical observations
  80. Chandra observation of the X-ray afterglow of GRB991216
  81. GRB 991216, optical observations
  82. GRB 991216 Optical Observations
  83. GRB 991216 Optical spectroscopy/imaging
  84. VLT spectra of GRB991216
  85. GRB991216 Optical and IR observations
  86. K observations of GRB991216
  87. SAX J2303.2+0015 Optical observations
  88. IR observations of GRB991216
  89. GRB991216 radio observations
  90. GRB 991217 (SAX J2303.2+0015) Optical observations
  91. GRB991216 radio observations
  92. GRB991216 Spectroscopy
  93. Lowell/Perkins observation of GRB 991216
  94. GRB991216, optical observations
  95. GRB991216 Optical and infrared observations of Beethoven Burst
  96. Refined IPN localization of GRB991216
  97. GRB 991216 Radio Observations
  98. GRB 991217
  99. GRB 991208 Keck Spectroscopy
  100. GRB 991208 Infrared Detection

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