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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"

18395 results found.

  1. GRB 050219b: Swift-BAT detection of a burst
  2. GRB 050219b: CORRECTION: Swift XRT Position
  3. GRB 050219b: Swift XRT Position
  4. GRB 050219a, optical observations
  5. GRB 050219a: Refined XRT position
  6. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  7. GRB 050219: Swift-BAT detection of a burst
  8. GRB050215b: Swift UVOT Detection of Afterglow Emission
  9. GRB 050219: Prompt X-ray position
  10. GRB 050215b: XRT confirmation of IR afterglow candidate
  11. GRB050215b: P60 Optical Observations
  12. GRB 050215b: Swift XRT Source Variability
  13. GRB 050215B: candidate afterglow
  14. GRB 050215b : Lulin follow-up observation
  15. GRB 050215b, BOOTES-2 simultaneous optical observations
  16. GRB 050215B: UKIRT K-band imaging
  17. GRB 050215b: Swift XRT Observations
  18. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  19. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  20. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  21. GRB050215B: ROTSE-III optical observations
  22. GRB050215A: ROTSE-III Optical Observations
  23. short/hard GRB 050202, optical observations
  24. GRB 050128: Radio observations
  25. Further analysis of the short Swift-BAT GRB 050202
  26. GRB 050202: Second epoch radio observations
  27. GRB050202: Radio Observations
  28. GRB 050202: Short burst detected by Swift-BAT
  29. SGR1806-20: Swift-BAT detection of a large normal burst
  30. GRB050128: Faulkes Telescope South observations
  31. GRB050128,optical observations
  32. GRB050126: Updated Swift XRT Position
  33. GRB 050126: Radio Observations
  34. GRB050128 Swift-BAT observations
  35. GRB 050128: Swift XRT prompt afterglow position
  36. GRB 050124: K-band afterglow observations
  37. GRB050126: MASTER optical limit for KECK OT
  38. GRB050126: Burst Parameters Measured by BAT
  39. GRB050126: MASTER optical observations
  40. GRB 050126: Prompt XRT detection and localization
  41. GRB050124: No Swift UVOT Detection of Afterglow Emission
  42. GRB 050117a: Radio Observations
  43. GRB050124,optical observation
  44. GRB050124: Updated Swift XRT Position and Fluxes
  45. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  46. GRB050124: Refined BAT position, spectral and fluence information
  47. GRB050124: Swift-BAT position of a double-peaked burst
  48. GRB050117a: Radio Observations
  49. GRB050117a: Refined analysis
  50. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  51. GRB050117b: Swift-BAT detection of a weak burst
  52. GRB050117: optical observation
  53. GRB 050117, I-band observations
  54. GRB 050117: Optical observation
  55. GRB050117: Refined XRT position
  56. GRB050117: MASTER optical observations
  57. MASTER:GRB050117 SWIFT
  58. GRB050117: Swift-BAT detection of a long multi-peaked burst
  59. GRB050117: Swift XRT Position
  60. SGR1806-20: Swift-BAT observations of two additional bursts
  61. SGR 1806-20, RHESSI observations of the 041227 giant flare
  62. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  63. GRB 041217: Optical observations
  64. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  65. GRB041228: ROTSE-III Optical Observations
  66. GRB041228: Swift-BAT detection of a burst
  67. GRB041219; RXTE ASM Observations
  68. NIR Observations of GRB 041219
  69. GRB041226: ROTSE-III Optical Observations
  70. GRB041226: Swift-BAT detection of a burst
  71. GRB041223: decay of the afterglow
  72. GRB041224: ROTSE-III Optical Observations
  73. GRB 041223: XRT afterglow spectrum and light curve
  74. GRB 041223 Fluence measured by Swift-BAT
  75. GRB041224: Swift-BAT detection of a soft burst
  76. GRB041223: optical and NIR observations with REM
  77. Swift-BAT Time History of GRB041219
  78. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  79. GRB041223: ROTSE-III Optical Observations
  80. GRB041223: Swift-BAT detection of a bright long burst
  81. GRB041220: Swift-BAT burst
  82. GRB 041219 Optical Observations
  83. GRB041219c: Third Burst in One Day from Swift-BAT
  84. GRB041219b: A Swift-BAT burst
  85. Swift-BAT detection of the bright long burst GRB041219
  86. GRB041217: optical limit 30 min after GRB
  87. GRB041217: Optical Observations
  88. GRB041217: NIR and optical observations with REM
  89. GRB041217: P60 Optical Observations
  90. GRB041217: Infrared Observations
  91. GRB041217: The First GRB Located On-Board Swift
  92. GRB040916: Optical observations
  93. GRB040422: optical and NIR observations at the VLT
  94. GRB040223, improved XMM position
  95. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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