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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').

18289 results found.

  1. GRB 050219: Swift-BAT detection of a burst
  2. GRB050215b: Swift UVOT Detection of Afterglow Emission
  3. GRB 050219: Prompt X-ray position
  4. GRB 050215b: XRT confirmation of IR afterglow candidate
  5. GRB050215b: P60 Optical Observations
  6. GRB 050215b: Swift XRT Source Variability
  7. GRB 050215B: candidate afterglow
  8. GRB 050215b : Lulin follow-up observation
  9. GRB 050215b, BOOTES-2 simultaneous optical observations
  10. GRB 050215B: UKIRT K-band imaging
  11. GRB 050215b: Swift XRT Observations
  12. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  13. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  14. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  15. GRB050215B: ROTSE-III optical observations
  16. GRB050215A: ROTSE-III Optical Observations
  17. short/hard GRB 050202, optical observations
  18. GRB 050128: Radio observations
  19. Further analysis of the short Swift-BAT GRB 050202
  20. GRB 050202: Second epoch radio observations
  21. GRB050202: Radio Observations
  22. GRB 050202: Short burst detected by Swift-BAT
  23. SGR1806-20: Swift-BAT detection of a large normal burst
  24. GRB050128: Faulkes Telescope South observations
  25. GRB050128,optical observations
  26. GRB050126: Updated Swift XRT Position
  27. GRB 050126: Radio Observations
  28. GRB050128 Swift-BAT observations
  29. GRB 050128: Swift XRT prompt afterglow position
  30. GRB 050124: K-band afterglow observations
  31. GRB050126: MASTER optical limit for KECK OT
  32. GRB050126: Burst Parameters Measured by BAT
  33. GRB050126: MASTER optical observations
  34. GRB 050126: Prompt XRT detection and localization
  35. GRB050124: No Swift UVOT Detection of Afterglow Emission
  36. GRB 050117a: Radio Observations
  37. GRB050124,optical observation
  38. GRB050124: Updated Swift XRT Position and Fluxes
  39. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  40. GRB050124: Refined BAT position, spectral and fluence information
  41. GRB050124: Swift-BAT position of a double-peaked burst
  42. GRB050117a: Radio Observations
  43. GRB050117a: Refined analysis
  44. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  45. GRB050117b: Swift-BAT detection of a weak burst
  46. GRB050117: optical observation
  47. GRB 050117, I-band observations
  48. GRB 050117: Optical observation
  49. GRB050117: Refined XRT position
  50. GRB050117: MASTER optical observations
  51. MASTER:GRB050117 SWIFT
  52. GRB050117: Swift-BAT detection of a long multi-peaked burst
  53. GRB050117: Swift XRT Position
  54. SGR1806-20: Swift-BAT observations of two additional bursts
  55. SGR 1806-20, RHESSI observations of the 041227 giant flare
  56. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  57. GRB 041217: Optical observations
  58. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  59. GRB041228: ROTSE-III Optical Observations
  60. GRB041228: Swift-BAT detection of a burst
  61. GRB041219; RXTE ASM Observations
  62. NIR Observations of GRB 041219
  63. GRB041226: ROTSE-III Optical Observations
  64. GRB041226: Swift-BAT detection of a burst
  65. GRB041223: decay of the afterglow
  66. GRB041224: ROTSE-III Optical Observations
  67. GRB 041223: XRT afterglow spectrum and light curve
  68. GRB 041223 Fluence measured by Swift-BAT
  69. GRB041224: Swift-BAT detection of a soft burst
  70. GRB041223: optical and NIR observations with REM
  71. Swift-BAT Time History of GRB041219
  72. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  73. GRB041223: ROTSE-III Optical Observations
  74. GRB041223: Swift-BAT detection of a bright long burst
  75. GRB041220: Swift-BAT burst
  76. GRB 041219 Optical Observations
  77. GRB041219c: Third Burst in One Day from Swift-BAT
  78. GRB041219b: A Swift-BAT burst
  79. Swift-BAT detection of the bright long burst GRB041219
  80. GRB041217: optical limit 30 min after GRB
  81. GRB041217: Optical Observations
  82. GRB041217: NIR and optical observations with REM
  83. GRB041217: P60 Optical Observations
  84. GRB041217: Infrared Observations
  85. GRB041217: The First GRB Located On-Board Swift
  86. GRB040916: Optical observations
  87. GRB040422: optical and NIR observations at the VLT
  88. GRB040223, improved XMM position
  89. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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