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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"

20955 results found.

  1. GRB051028:MASTER observations
  2. GRB051028:MASTER optical observations
  3. GRB051022: Swift XRT measurement of jet break
  4. SGR 1806-20: continued moderate activity seen with INTEGRAL
  5. GRB 051021, Optical Observations
  6. GRB 051022: XRT Refined Spectral and Temporal Analysis
  7. Chandra Observations of GRB 051022
  8. GRB051012: Swift-XRT analysis
  9. GRB 051022 Chandra Observations scheduled
  10. GRB051021B: Swift XRT refined analysis
  11. GRB051021a: optical observations
  12. GRB 051022: WSRT Radio Detection
  13. GRB 051022, mm counterpart
  14. GRB051022: Radio Counterpart
  15. GRB051022: IR observations
  16. GRB 051022: SOAR JKs Observations
  17. GRB051022: Optical Observations
  18. GRB 051022: Magellan NIR imaging
  19. GRB 051021: PROMPT RcIc Observations
  20. GRB051021b: Magellan IR Imaging
  21. GRB 051022, J & K-band observation
  22. GRB 051021, SMARTS optical/IR observations
  23. GRB 051021: P200 Ks Observations
  24. GRB 051022: SSO40 Optical Observations
  25. GRB051022 (=H3590), A GRB Detected By HETE
  26. GRB 051022: Optical observations
  27. GRB 051021: SOAR NIR Observations
  28. GRB051021: Swift XRT analysis
  29. GRB 051021 : optical afterglow observation at Lulin
  30. GRB 051021: Optical observations
  31. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  32. GRB 051021: Optical observations and candidate afterglow
  33. GRB 051016b: Gemini Near IR Observations
  34. GRB 051016: LCO optical and near-IR imaging
  35. GRB 051016: PROMPT Observations
  36. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  37. GRB051006: optical observations
  38. GRB050805A: Rc optical observations
  39. GRB051008: optical candidate
  40. GRB051008: optical observation
  41. GRB051008: Swift XRT refined analysis
  42. GRB 051008, optical observations
  43. GRB 051006: P60 Observations
  44. GRB 051006: optical observations at Sierra Nevada
  45. GRB 050906, summary of radio observations
  46. GRB 050925: Second Epoch WSRT Radio Observations
  47. GRB 051001: Swift XRT refined analysis
  48. GRB 051001, optical observations at Mt. John
  49. GRB 051001: AAT infra-red observations
  50. GRB 051001: ROTSE-III Optical Limits
  51. GRB050908: optical observations
  52. GRB 050922C: further VLT observations
  53. GRB050922C: UVES/VLT high resolution spectroscopy
  54. GRB/SGR 050925: IR Observations
  55. GRB 050922C: break in the lightcurve
  56. GRB 050925: WSRT Radio Observations
  57. GRB050925: Swift UVOT upper limits
  58. GRB 050925 : I-band observation at Xinglong observatory
  59. GRB050922C: TNG spectroscopic observations
  60. GRB050922C: Optical Observations
  61. GRB 050922C: Swift XRT refined analysis
  62. HETE Fregate observations of GRB 050922C
  63. GRB050922C: optical observations
  64. GRB 050922C: NOT optical observations
  65. GRB 050922C: ROTSE-IIId Refined Analysis
  66. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  67. GRB050918: Possible Swift/XRT detected afterglow
  68. GRB 050915a: Radio Observations
  69. Swift-BAT trigger 155764 is not a GRB
  70. GRB 050915b, SMARTS optical/IR observations of the XRT position
  71. GRB 050915b, SMARTS optical/IR observations
  72. GRB 050915: IR Observations
  73. GRB050915: P60 Optical Observations
  74. GRB050915, optical observations
  75. Swift-BAT trigger 155072 ground analysis
  76. GRB 050911: LCO limits on a variable source
  77. GRB050911: Swift UVOT followup observations
  78. GRB 050911, optical content of Swift/XRT error box
  79. GRB 050911: LCO observations
  80. GRB 050911, optical observations
  81. GRB 050910a: TAROT early optical limits
  82. RBO GRB 050908 observations
  83. WIRO observations in I of GRB 050908
  84. GRB 050906: Possible X-ray Counterpart
  85. GRB 050906: RTT150 optical observations
  86. GRB050908: VLT R-band decay index.
  87. GRB 050908: Optical observations
  88. Gemini Spectroscopy of GRB 050908
  89. GRB 050908: Prompt PROMPT Observations
  90. GRB 050908: KAIT observations
  91. GRB 050908: P60 Confirmation of Optical Afterglow
  92. GRB 050908: Optical Observations
  93. GRB 050908: Swift detection of a burst
  94. Swift trigger 154073 is not a GRB
  95. GRB 050906: Optical observations at the Very Large Telescope
  96. GRB050904: CrAO optical observations
  97. GRB 050906: Swift XRT upper limit
  98. GRB 050906: Radio Observations
  99. GRB050906: P60 Observations
  100. GRB 050904: more VLT NIR observations

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