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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"

19594 results found.

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

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