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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: HST/STIS CCD Imaging of the field
  2. IPN error box for GRB000307
  3. GRB 000301c: K' observations
  4. GRB000301C, optical R-band observations
  5. GRB000301c - R photometry and nearby faint source confirmation
  6. GRB 000301C, Optical Observation
  7. GRB 000301c: K' observations
  8. GRB 000301C Optical Observations
  9. GRB 000301C: K' Observations
  10. GRB000301C OT candidate optical observations
  11. GRB000301C - Host galaxy not detected in R (?)
  12. Optical observations of GRB000301c
  13. GRB000301C, Radio observations
  14. GRB000301C, Radio observations
  15. GRB000301C optical observations
  16. GRB000301C, near-infrared observations (JHK' imaging)
  17. GRB 000301c near-IR observations
  18. GRB 000301C, Optical Color
  19. GRB000301C, Optical Spectroscopy
  20. GRB 000301C, UBVRI field photometry
  21. GRB 000301C, Optical Observation
  22. GRB000301C, optical observations
  23. GRB000301C 250 GHz detection
  24. GRB 000301C R-band observation
  25. GRB 000301C, Optical Observation
  26. GRB000301C, near-infrared observations (JHK' photometry)
  27. GRB 000301C: OT confirmed
  28. GRB000301c optical observations
  29. GRB 000301A, Radio Observations
  30. GRB000301C, optical observations
  31. GRB000301c, near-infrared observations
  32. GRB000301C
  33. GRB 000301C : Optical Candidate
  34. Radio observations of the error box of GRB000301A
  35. GRB000301C: RXTE/ASM and IPN localizations
  36. GRB000301A [IPN Position]
  37. GRB000226 [IPN Position]
  38. HST Observations of GRB 990712
  39. GRB 000214 near-IR observations
  40. GRB 000115 Optical observations
  41. GRB 000214, Radio Observations
  42. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  43. GRB000210, Radio Observations
  44. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  45. GRB 000115, BVRI field photometry
  46. GRB000214: BeppoSAX GRBM and WFC Detection
  47. IPN annulus for GRB000214
  48. BATSE GRB trigger criterion changed
  49. Optical observations of GRB000210
  50. GRB000210 X-ray afterglow
  51. GRB000214: X-ray afterglow candidate
  52. GRB000214 refined BeppoSAX-WFC position
  53. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  54. GRB 000210: BATSE Observations
  55. Correction to Chandra Position of GRB000210 afterglow
  56. Optical observations of the Chandra X-ray source for GRB000210
  57. GRB000210, Radio Observations
  58. Optical candidate for GRB000210
  59. Chandra Observations of GRB000210 X-ray Afterglow
  60. IPN triangulation of GRB000210
  61. GRB000210: possible afterglow detection with BeppoSAX NFI
  62. GRB000201, Radio Observations
  63. GRB000210: BeppoSAX GRBM and WFC Detection
  64. SAX_WFC_GRB_NOTICE
  65. SAX_WFC_GRB_NOTICE
  66. Optical observations of GRB000131
  67. GRB000201 Optical Observations
  68. GRB 000201: TAROT optical observations
  69. GRB 000131 Optical Observations
  70. GRB000126 Optical Observations
  71. BATSE GRB trigger criteria changed
  72. GRB 991208, radio observations
  73. BATSE+IPN location of GRB000131
  74. IPN localization of GRB000131
  75. GRB 000126, optical observations
  76. GRB000126, optical observations
  77. BATSE location of GRB000126
  78. IPN localization of GRB000126
  79. GRB 000115 Optical observations
  80. BATSE Observations of GRB000115
  81. Correction to GCN 520 (IPN annulus for GRB000115)
  82. IPN annulus for GRB000115
  83. Second RXTE Observation of GRB 000115
  84. GRB991216, UBVRIJHK field photometry
  85. GRB991216 late optical observation
  86. Single IPN error box for GRB991229
  87. GCN resumes full operations
  88. GRB 991216 VLBA Observations
  89. BEPPOSAX GRBM Localization of GRB991226
  90. IPN error boxes for GRB991229
  91. GRB 991216: J band spectrophotometry
  92. GRB 991216: Detection of the Host and/or Absorber Galaxy
  93. IPN localization of GRB991226
  94. Single IPN error box for GRB991221
  95. IPN error boxes for GRB991221
  96. GRB 991216 RXTE ASM Observations
  97. IPN error box for GRB991216
  98. GRB 991216: Updated BATSE parameters
  99. Lowell/Perkins observation of GRB 991216
  100. GRB 991217 (SAX J2303.2+0015) Optical observations

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