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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').

17103 results found.

  1. GRB050223: ROTSE-III Optical Observations
  2. GRB 050223 Swift/BAT detection of a burst
  3. GRB 050223: Swift XRT Position
  4. GRB050219b: CORRECTION to time of UVOT observations
  5. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  6. GRB 050219b: CORRECTION to refined XRT position
  7. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  8. GRB 050219b: Refined XRT position
  9. GRB 050219b: Swift-BAT detection of a burst
  10. GRB 050219b: CORRECTION: Swift XRT Position
  11. GRB 050219b: Swift XRT Position
  12. GRB 050219a, optical observations
  13. GRB 050219a: Refined XRT position
  14. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  15. GRB 050219: Swift-BAT detection of a burst
  16. GRB050215b: Swift UVOT Detection of Afterglow Emission
  17. GRB 050219: Prompt X-ray position
  18. GRB 050215b: XRT confirmation of IR afterglow candidate
  19. GRB050215b: P60 Optical Observations
  20. GRB 050215b: Swift XRT Source Variability
  21. GRB 050215B: candidate afterglow
  22. GRB 050215b : Lulin follow-up observation
  23. GRB 050215b, BOOTES-2 simultaneous optical observations
  24. GRB 050215B: UKIRT K-band imaging
  25. GRB 050215b: Swift XRT Observations
  26. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  27. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  28. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  29. GRB050215B: ROTSE-III optical observations
  30. GRB050215A: ROTSE-III Optical Observations
  31. short/hard GRB 050202, optical observations
  32. GRB 050128: Radio observations
  33. Further analysis of the short Swift-BAT GRB 050202
  34. GRB 050202: Second epoch radio observations
  35. GRB050202: Radio Observations
  36. GRB 050202: Short burst detected by Swift-BAT
  37. SGR1806-20: Swift-BAT detection of a large normal burst
  38. GRB050128: Faulkes Telescope South observations
  39. GRB050128,optical observations
  40. GRB050126: Updated Swift XRT Position
  41. GRB 050126: Radio Observations
  42. GRB050128 Swift-BAT observations
  43. GRB 050128: Swift XRT prompt afterglow position
  44. GRB 050124: K-band afterglow observations
  45. GRB050126: MASTER optical limit for KECK OT
  46. GRB050126: Burst Parameters Measured by BAT
  47. GRB050126: MASTER optical observations
  48. GRB 050126: Prompt XRT detection and localization
  49. GRB050124: No Swift UVOT Detection of Afterglow Emission
  50. GRB 050117a: Radio Observations
  51. GRB050124,optical observation
  52. GRB050124: Updated Swift XRT Position and Fluxes
  53. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  54. GRB050124: Refined BAT position, spectral and fluence information
  55. GRB050124: Swift-BAT position of a double-peaked burst
  56. GRB050117a: Radio Observations
  57. GRB050117a: Refined analysis
  58. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  59. GRB050117b: Swift-BAT detection of a weak burst
  60. GRB050117: optical observation
  61. GRB 050117, I-band observations
  62. GRB 050117: Optical observation
  63. GRB050117: Refined XRT position
  64. GRB050117: MASTER optical observations
  65. MASTER:GRB050117 SWIFT
  66. GRB050117: Swift-BAT detection of a long multi-peaked burst
  67. GRB050117: Swift XRT Position
  68. SGR1806-20: Swift-BAT observations of two additional bursts
  69. SGR 1806-20, RHESSI observations of the 041227 giant flare
  70. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  71. GRB 041217: Optical observations
  72. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  73. GRB041228: ROTSE-III Optical Observations
  74. GRB041228: Swift-BAT detection of a burst
  75. GRB041219; RXTE ASM Observations
  76. NIR Observations of GRB 041219
  77. GRB041226: ROTSE-III Optical Observations
  78. GRB041226: Swift-BAT detection of a burst
  79. GRB041223: decay of the afterglow
  80. GRB041224: ROTSE-III Optical Observations
  81. GRB 041223: XRT afterglow spectrum and light curve
  82. GRB 041223 Fluence measured by Swift-BAT
  83. GRB041224: Swift-BAT detection of a soft burst
  84. GRB041223: optical and NIR observations with REM
  85. Swift-BAT Time History of GRB041219
  86. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  87. GRB041223: ROTSE-III Optical Observations
  88. GRB041223: Swift-BAT detection of a bright long burst
  89. GRB041220: Swift-BAT burst
  90. GRB 041219 Optical Observations
  91. GRB041219c: Third Burst in One Day from Swift-BAT
  92. GRB041219b: A Swift-BAT burst
  93. Swift-BAT detection of the bright long burst GRB041219
  94. GRB041217: optical limit 30 min after GRB
  95. GRB041217: Optical Observations
  96. GRB041217: NIR and optical observations with REM
  97. GRB041217: P60 Optical Observations
  98. GRB041217: Infrared Observations
  99. GRB041217: The First GRB Located On-Board Swift
  100. GRB040916: Optical observations

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