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

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