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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"

19185 results found.

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

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