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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').

17828 results found.

  1. GRB 050315: Swift XRT Position
  2. GRB 050315: Early Observations with Swift/UVOT
  3. Swift-BAT detection of GRB 050315
  4. GRB050223: No XMM-Newton OM detection of afterglow emission
  5. GRB050309: CONCAM pre-trigger and trigger coincident optical
  6. GRB 050126: Redshift determination
  7. Swift-BAT trigger 107873: No Swift XRT counterpart
  8. GRB 050306: Confirmation of X-ray afterglow
  9. GRB 050309, Early optical limits from RAPTOR
  10. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  11. GRB 050309 : Lulin R-band observation
  12. Swift 107873: P60 Optical Observations
  13. GRB 050306: CORRECTION to date of observation
  14. GRB 050306: No Swift UVOT Optical Counterpart Detected
  15. GRB 050306: Possible X-ray Afterglow Position from the Swift
  16. Swift trigger 107518: optical observation
  17. GRB 050306,optical observation
  18. GRB 050306: Swift-BAT detection of a long burst
  19. GRB050215B: Late-Time Swift UVOT Observations
  20. PROMPT VRcIc Observations of GRB 050223
  21. GRB 050223: optical observations
  22. GRB050223 XMM-Newton observation
  23. INTEGRAL detection of GRB 050223
  24. GRB050223: No Swift UVOT Detection of Afterglow Emission
  25. GRB050223: ROTSE-III Optical Observations
  26. GRB 050223 Swift/BAT detection of a burst
  27. GRB 050223: Swift XRT Position
  28. GRB050219b: CORRECTION to time of UVOT observations
  29. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  30. GRB 050219b: CORRECTION to refined XRT position
  31. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  32. GRB 050219b: Refined XRT position
  33. GRB 050219b: Swift-BAT detection of a burst
  34. GRB 050219b: CORRECTION: Swift XRT Position
  35. GRB 050219b: Swift XRT Position
  36. GRB 050219a, optical observations
  37. GRB 050219a: Refined XRT position
  38. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  39. GRB 050219: Swift-BAT detection of a burst
  40. GRB050215b: Swift UVOT Detection of Afterglow Emission
  41. GRB 050219: Prompt X-ray position
  42. GRB 050215b: XRT confirmation of IR afterglow candidate
  43. GRB050215b: P60 Optical Observations
  44. GRB 050215b: Swift XRT Source Variability
  45. GRB 050215B: candidate afterglow
  46. GRB 050215b : Lulin follow-up observation
  47. GRB 050215b, BOOTES-2 simultaneous optical observations
  48. GRB 050215B: UKIRT K-band imaging
  49. GRB 050215b: Swift XRT Observations
  50. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  51. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  52. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  53. GRB050215B: ROTSE-III optical observations
  54. GRB050215A: ROTSE-III Optical Observations
  55. short/hard GRB 050202, optical observations
  56. GRB 050128: Radio observations
  57. Further analysis of the short Swift-BAT GRB 050202
  58. GRB 050202: Second epoch radio observations
  59. GRB050202: Radio Observations
  60. GRB 050202: Short burst detected by Swift-BAT
  61. SGR1806-20: Swift-BAT detection of a large normal burst
  62. GRB050128: Faulkes Telescope South observations
  63. GRB050128,optical observations
  64. GRB050126: Updated Swift XRT Position
  65. GRB 050126: Radio Observations
  66. GRB050128 Swift-BAT observations
  67. GRB 050128: Swift XRT prompt afterglow position
  68. GRB 050124: K-band afterglow observations
  69. GRB050126: MASTER optical limit for KECK OT
  70. GRB050126: Burst Parameters Measured by BAT
  71. GRB050126: MASTER optical observations
  72. GRB 050126: Prompt XRT detection and localization
  73. GRB050124: No Swift UVOT Detection of Afterglow Emission
  74. GRB 050117a: Radio Observations
  75. GRB050124,optical observation
  76. GRB050124: Updated Swift XRT Position and Fluxes
  77. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  78. GRB050124: Refined BAT position, spectral and fluence information
  79. GRB050124: Swift-BAT position of a double-peaked burst
  80. GRB050117a: Radio Observations
  81. GRB050117a: Refined analysis
  82. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  83. GRB050117b: Swift-BAT detection of a weak burst
  84. GRB050117: optical observation
  85. GRB 050117, I-band observations
  86. GRB 050117: Optical observation
  87. GRB050117: Refined XRT position
  88. GRB050117: MASTER optical observations
  89. MASTER:GRB050117 SWIFT
  90. GRB050117: Swift-BAT detection of a long multi-peaked burst
  91. GRB050117: Swift XRT Position
  92. SGR1806-20: Swift-BAT observations of two additional bursts
  93. SGR 1806-20, RHESSI observations of the 041227 giant flare
  94. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  95. GRB 041217: Optical observations
  96. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  97. GRB041228: ROTSE-III Optical Observations
  98. GRB041228: Swift-BAT detection of a burst
  99. GRB041219; RXTE ASM Observations
  100. NIR Observations of GRB 041219

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