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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"

19590 results found.

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

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