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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').

17114 results found.

  1. GRB 050306: No Swift UVOT Optical Counterpart Detected
  2. GRB 050306: Possible X-ray Afterglow Position from the Swift
  3. Swift trigger 107518: optical observation
  4. GRB 050306,optical observation
  5. GRB 050306: Swift-BAT detection of a long burst
  6. GRB050215B: Late-Time Swift UVOT Observations
  7. PROMPT VRcIc Observations of GRB 050223
  8. GRB 050223: optical observations
  9. GRB050223 XMM-Newton observation
  10. INTEGRAL detection of GRB 050223
  11. GRB050223: No Swift UVOT Detection of Afterglow Emission
  12. GRB050223: ROTSE-III Optical Observations
  13. GRB 050223 Swift/BAT detection of a burst
  14. GRB 050223: Swift XRT Position
  15. GRB050219b: CORRECTION to time of UVOT observations
  16. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  17. GRB 050219b: CORRECTION to refined XRT position
  18. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  19. GRB 050219b: Refined XRT position
  20. GRB 050219b: Swift-BAT detection of a burst
  21. GRB 050219b: CORRECTION: Swift XRT Position
  22. GRB 050219b: Swift XRT Position
  23. GRB 050219a, optical observations
  24. GRB 050219a: Refined XRT position
  25. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  26. GRB 050219: Swift-BAT detection of a burst
  27. GRB050215b: Swift UVOT Detection of Afterglow Emission
  28. GRB 050219: Prompt X-ray position
  29. GRB 050215b: XRT confirmation of IR afterglow candidate
  30. GRB050215b: P60 Optical Observations
  31. GRB 050215b: Swift XRT Source Variability
  32. GRB 050215B: candidate afterglow
  33. GRB 050215b : Lulin follow-up observation
  34. GRB 050215b, BOOTES-2 simultaneous optical observations
  35. GRB 050215B: UKIRT K-band imaging
  36. GRB 050215b: Swift XRT Observations
  37. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  38. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  39. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  40. GRB050215B: ROTSE-III optical observations
  41. GRB050215A: ROTSE-III Optical Observations
  42. short/hard GRB 050202, optical observations
  43. GRB 050128: Radio observations
  44. Further analysis of the short Swift-BAT GRB 050202
  45. GRB 050202: Second epoch radio observations
  46. GRB050202: Radio Observations
  47. GRB 050202: Short burst detected by Swift-BAT
  48. SGR1806-20: Swift-BAT detection of a large normal burst
  49. GRB050128: Faulkes Telescope South observations
  50. GRB050128,optical observations
  51. GRB050126: Updated Swift XRT Position
  52. GRB 050126: Radio Observations
  53. GRB050128 Swift-BAT observations
  54. GRB 050128: Swift XRT prompt afterglow position
  55. GRB 050124: K-band afterglow observations
  56. GRB050126: MASTER optical limit for KECK OT
  57. GRB050126: Burst Parameters Measured by BAT
  58. GRB050126: MASTER optical observations
  59. GRB 050126: Prompt XRT detection and localization
  60. GRB050124: No Swift UVOT Detection of Afterglow Emission
  61. GRB 050117a: Radio Observations
  62. GRB050124,optical observation
  63. GRB050124: Updated Swift XRT Position and Fluxes
  64. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  65. GRB050124: Refined BAT position, spectral and fluence information
  66. GRB050124: Swift-BAT position of a double-peaked burst
  67. GRB050117a: Radio Observations
  68. GRB050117a: Refined analysis
  69. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  70. GRB050117b: Swift-BAT detection of a weak burst
  71. GRB050117: optical observation
  72. GRB 050117, I-band observations
  73. GRB 050117: Optical observation
  74. GRB050117: Refined XRT position
  75. GRB050117: MASTER optical observations
  76. MASTER:GRB050117 SWIFT
  77. GRB050117: Swift-BAT detection of a long multi-peaked burst
  78. GRB050117: Swift XRT Position
  79. SGR1806-20: Swift-BAT observations of two additional bursts
  80. SGR 1806-20, RHESSI observations of the 041227 giant flare
  81. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  82. GRB 041217: Optical observations
  83. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  84. GRB041228: ROTSE-III Optical Observations
  85. GRB041228: Swift-BAT detection of a burst
  86. GRB041219; RXTE ASM Observations
  87. NIR Observations of GRB 041219
  88. GRB041226: ROTSE-III Optical Observations
  89. GRB041226: Swift-BAT detection of a burst
  90. GRB041223: decay of the afterglow
  91. GRB041224: ROTSE-III Optical Observations
  92. GRB 041223: XRT afterglow spectrum and light curve
  93. GRB 041223 Fluence measured by Swift-BAT
  94. GRB041224: Swift-BAT detection of a soft burst
  95. GRB041223: optical and NIR observations with REM
  96. Swift-BAT Time History of GRB041219
  97. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  98. GRB041223: ROTSE-III Optical Observations
  99. GRB041223: Swift-BAT detection of a bright long burst
  100. GRB041220: Swift-BAT burst

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