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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"

21392 results found.

  1. GRB 050215b: Swift XRT Source Variability
  2. GRB 050215B: candidate afterglow
  3. GRB 050215b : Lulin follow-up observation
  4. GRB 050215b, BOOTES-2 simultaneous optical observations
  5. GRB 050215B: UKIRT K-band imaging
  6. GRB 050215b: Swift XRT Observations
  7. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  8. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  9. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  10. GRB050215B: ROTSE-III optical observations
  11. GRB050215A: ROTSE-III Optical Observations
  12. short/hard GRB 050202, optical observations
  13. GRB 050128: Radio observations
  14. Further analysis of the short Swift-BAT GRB 050202
  15. GRB 050202: Second epoch radio observations
  16. GRB050202: Radio Observations
  17. GRB 050202: Short burst detected by Swift-BAT
  18. GRB 050128 Optical observation with REM
  19. SGR1806-20: Swift-BAT detection of a large normal burst
  20. GRB050128: Faulkes Telescope South observations
  21. GRB 050128: near-infrared observations with REM
  22. GRB050128,optical observations
  23. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  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: Detection of NIR afterglow with Keck/NIRC
  33. GRB 050126: Prompt XRT detection and localization
  34. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  35. GRB050124: No Swift UVOT Detection of Afterglow Emission
  36. GRB 050117a: Radio Observations
  37. GRB 050124: NIR Candidates from Keck/NIRC
  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. GRB050117: Palomar WIRC Ks-band observations
  47. GRB050117b: Swift-BAT detection of a weak burst
  48. GRB050117: optical observation
  49. GRB 050117, I-band observations
  50. GRB 050117: Optical observation
  51. GRB050117: Refined XRT position
  52. GRB050117: MASTER optical observations
  53. MASTER:GRB050117 SWIFT
  54. GRB050117: Swift-BAT detection of a long multi-peaked burst
  55. GRB050117: Swift XRT Position
  56. SGR1806-20: Swift-BAT observations of two additional bursts
  57. SGR 1806-20, RHESSI observations of the 041227 giant flare
  58. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  59. GRB 041217: Optical observations
  60. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  61. GRB041228: ROTSE-III Optical Observations
  62. GRB041228: Swift-BAT detection of a burst
  63. GRB041219; RXTE ASM Observations
  64. NIR Observations of GRB 041219
  65. GRB041226: ROTSE-III Optical Observations
  66. GRB041226: Swift-BAT detection of a burst
  67. GRB041223: decay of the afterglow
  68. GRB041224: ROTSE-III Optical Observations
  69. GRB 041223: XRT afterglow spectrum and light curve
  70. GRB 041223 Fluence measured by Swift-BAT
  71. GRB041224: Swift-BAT detection of a soft burst
  72. GRB041223: optical and NIR observations with REM
  73. Swift-BAT Time History of GRB041219
  74. GRB 041223: Detection of Optical Transient with LCO40
  75. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  76. GRB041223: ROTSE-III Optical Observations
  77. GRB041223: Swift-BAT detection of a bright long burst
  78. GRB041220: Swift-BAT burst
  79. GRB 041219 Optical Observations
  80. GRB041219c: Third Burst in One Day from Swift-BAT
  81. GRB041219b: A Swift-BAT burst
  82. Swift-BAT detection of the bright long burst GRB041219
  83. GRB041217: optical limit 30 min after GRB
  84. GRB041217: Optical Observations
  85. GRB041217: NIR and optical observations with REM
  86. GRB041217: P60 Optical Observations
  87. GRB041217: Infrared Observations
  88. GRB041217: The First GRB Located On-Board Swift
  89. GRB040916: Optical observations
  90. GRB040422: optical and NIR observations at the VLT
  91. GRB040223, improved XMM position
  92. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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