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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"

20951 results found.

  1. GRB 051021, Optical Observations
  2. GRB 051022: XRT Refined Spectral and Temporal Analysis
  3. Chandra Observations of GRB 051022
  4. GRB051012: Swift-XRT analysis
  5. GRB 051022 Chandra Observations scheduled
  6. GRB051021B: Swift XRT refined analysis
  7. GRB051021a: optical observations
  8. GRB 051022: WSRT Radio Detection
  9. GRB 051022, mm counterpart
  10. GRB051022: Radio Counterpart
  11. GRB051022: IR observations
  12. GRB 051022: SOAR JKs Observations
  13. GRB051022: Optical Observations
  14. GRB 051022: Magellan NIR imaging
  15. GRB 051021: PROMPT RcIc Observations
  16. GRB051021b: Magellan IR Imaging
  17. GRB 051022, J & K-band observation
  18. GRB 051021, SMARTS optical/IR observations
  19. GRB 051021: P200 Ks Observations
  20. GRB 051022: SSO40 Optical Observations
  21. GRB051022 (=H3590), A GRB Detected By HETE
  22. GRB 051022: Optical observations
  23. GRB 051021: SOAR NIR Observations
  24. GRB051021: Swift XRT analysis
  25. GRB 051021 : optical afterglow observation at Lulin
  26. GRB 051021: Optical observations
  27. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  28. GRB 051021: Optical observations and candidate afterglow
  29. GRB 051016b: Gemini Near IR Observations
  30. GRB 051016: LCO optical and near-IR imaging
  31. GRB 051016: PROMPT Observations
  32. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  33. GRB051006: optical observations
  34. GRB050805A: Rc optical observations
  35. GRB051008: optical candidate
  36. GRB051008: optical observation
  37. GRB051008: Swift XRT refined analysis
  38. GRB 051008, optical observations
  39. GRB 051006: P60 Observations
  40. GRB 051006: optical observations at Sierra Nevada
  41. GRB 050906, summary of radio observations
  42. GRB 050925: Second Epoch WSRT Radio Observations
  43. GRB 051001: Swift XRT refined analysis
  44. GRB 051001, optical observations at Mt. John
  45. GRB 051001: AAT infra-red observations
  46. GRB 051001: ROTSE-III Optical Limits
  47. GRB050908: optical observations
  48. GRB 050922C: further VLT observations
  49. GRB050922C: UVES/VLT high resolution spectroscopy
  50. GRB/SGR 050925: IR Observations
  51. GRB 050922C: break in the lightcurve
  52. GRB 050925: WSRT Radio Observations
  53. GRB050925: Swift UVOT upper limits
  54. GRB 050925 : I-band observation at Xinglong observatory
  55. GRB050922C: TNG spectroscopic observations
  56. GRB050922C: Optical Observations
  57. GRB 050922C: Swift XRT refined analysis
  58. HETE Fregate observations of GRB 050922C
  59. GRB050922C: optical observations
  60. GRB 050922C: NOT optical observations
  61. GRB 050922C: ROTSE-IIId Refined Analysis
  62. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  63. GRB050918: Possible Swift/XRT detected afterglow
  64. GRB 050915a: Radio Observations
  65. Swift-BAT trigger 155764 is not a GRB
  66. GRB 050915b, SMARTS optical/IR observations of the XRT position
  67. GRB 050915b, SMARTS optical/IR observations
  68. GRB 050915: IR Observations
  69. GRB050915: P60 Optical Observations
  70. GRB050915, optical observations
  71. Swift-BAT trigger 155072 ground analysis
  72. GRB 050911: LCO limits on a variable source
  73. GRB050911: Swift UVOT followup observations
  74. GRB 050911, optical content of Swift/XRT error box
  75. GRB 050911: LCO observations
  76. GRB 050911, optical observations
  77. GRB 050910a: TAROT early optical limits
  78. RBO GRB 050908 observations
  79. WIRO observations in I of GRB 050908
  80. GRB 050906: Possible X-ray Counterpart
  81. GRB 050906: RTT150 optical observations
  82. GRB050908: VLT R-band decay index.
  83. GRB 050908: Optical observations
  84. Gemini Spectroscopy of GRB 050908
  85. GRB 050908: Prompt PROMPT Observations
  86. GRB 050908: KAIT observations
  87. GRB 050908: P60 Confirmation of Optical Afterglow
  88. GRB 050908: Optical Observations
  89. GRB 050908: Swift detection of a burst
  90. Swift trigger 154073 is not a GRB
  91. GRB 050906: Optical observations at the Very Large Telescope
  92. GRB050904: CrAO optical observations
  93. GRB 050906: Swift XRT upper limit
  94. GRB 050906: Radio Observations
  95. GRB050906: P60 Observations
  96. GRB 050904: more VLT NIR observations
  97. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  98. GRB 050904: More SOAR
  99. GRB 050904: Swift/UVOT observations
  100. GRB 050904: NIR object inside the XRT error box

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