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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"

19587 results found.

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

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