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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"

19588 results found.

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

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