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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"

19593 results found.

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

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