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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 050219a: Optical observations from LCO
  2. GRB 050219b: Optical and near-IR observations from LCO
  3. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  4. GRB 050219b: Refined XRT position
  5. GRB 050219b: Swift-BAT detection of a burst
  6. GRB 050219b: CORRECTION: Swift XRT Position
  7. GRB 050219b: Swift XRT Position
  8. GRB 050219a, optical observations
  9. GRB 050219a: Refined XRT position
  10. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  11. GRB 050219: Swift-BAT detection of a burst
  12. GRB050215b: Swift UVOT Detection of Afterglow Emission
  13. GRB 050219: Prompt X-ray position
  14. GRB 050215B: Radio Observations
  15. GRB 050215b: XRT confirmation of IR afterglow candidate
  16. GRB050215b: P60 Optical Observations
  17. GRB 050215b: Swift XRT Source Variability
  18. GRB 050215B: candidate afterglow
  19. GRB 050215b : Lulin follow-up observation
  20. GRB 050215b, BOOTES-2 simultaneous optical observations
  21. GRB 050215B: UKIRT K-band imaging
  22. GRB 050215b: Swift XRT Observations
  23. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  24. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  25. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  26. GRB 050215b, BOOTES-1B optical limit
  27. GRB050215B: ROTSE-III optical observations
  28. GRB050215A: ROTSE-III Optical Observations
  29. GRB050209: TAROT optical observations
  30. GRB 050209(=U11568): Duration and spectrum
  31. short/hard GRB 050202, optical observations
  32. GRB050209: REM optical observations
  33. GRB 050209 I-band observation
  34. GRB 050209 Optical observations
  35. GRB050209: P60 Optical Observations
  36. GRB050209 (=U11568): A Long GRB Detected by HETE
  37. GRB 050209: Optical observation
  38. GRB 050128: Radio observations
  39. Further analysis of the short Swift-BAT GRB 050202
  40. GRB 050202: Second epoch radio observations
  41. GRB 050129: Optical observations
  42. GRB050202: Radio Observations
  43. GRB 050202: Optical observations with LCO40
  44. GRB 050202: Short burst detected by Swift-BAT
  45. GRB 050128 Optical observation with REM
  46. GRB 050129: a weak long GRB detected with INTEGRAL
  47. SGR1806-20: Swift-BAT detection of a large normal burst
  48. GRB050128: Faulkes Telescope South observations
  49. GRB 050124: Radio Observations
  50. GRB 050128: near-infrared observations with REM
  51. GRB050128,optical observations
  52. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  53. GRB050126: Updated Swift XRT Position
  54. SGR 1806-20: GMRT results at 240 MHz band.
  55. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  56. GRB 050126: Radio Observations
  57. GRB050128 Swift-BAT observations
  58. GRB 050128: Swift XRT prompt afterglow position
  59. HETE #3667: P60 Observations
  60. GRB 050124: K-band afterglow observations
  61. GRB050126: MASTER optical limit for KECK OT
  62. GRB050126: Burst Parameters Measured by BAT
  63. GRB050126: MASTER optical observations
  64. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  65. GRB 050126: Prompt XRT detection and localization
  66. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  67. GRB050124: No Swift UVOT Detection of Afterglow Emission
  68. GRB 050124, SMARTS optical/IR observations
  69. GRB 050117a: Radio Observations
  70. GRB 050124 I-band observation
  71. GRB 050124: NIR Candidates from Keck/NIRC
  72. GRB050124,optical observation
  73. GRB 050124 : Lulin R-band follow-up observation
  74. GRB050124: Updated Swift XRT Position and Fluxes
  75. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  76. GRB050124: Refined BAT position, spectral and fluence information
  77. GRB050124: Swift-BAT position of a double-peaked burst
  78. GRB 050123 : I-band follow-up observation
  79. GRB050123: optical limit 1.8h before GRB
  80. GRB050123,optical observation
  81. GRB 050123: KAIT observations
  82. GRB050123: P60 Observations
  83. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  84. CFHTLS optical transient unlikely to be a GRB
  85. Unusual optical transient (GRB ???)
  86. GRB050117a: Radio Observations
  87. GRB050117a: Refined analysis
  88. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  89. GRB050117: Palomar WIRC Ks-band observations
  90. GRB050117b: Swift-BAT detection of a weak burst
  91. GRB050117: optical observation
  92. GRB 050117, I-band observations
  93. GRB 050117: Optical observation
  94. GRB050117: Refined XRT position
  95. GRB050117: MASTER optical observations
  96. MASTER:GRB050117 SWIFT
  97. GRB050117: Swift-BAT detection of a long multi-peaked burst
  98. GRB050117: Swift XRT Position
  99. SGR 1806-20: RXTE/PCA pulse frequency during flare
  100. Triangulation of Short Hard GRB050112 (large error box)

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