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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"

18397 results found.

  1. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  2. GRB 050219b: Refined XRT position
  3. GRB 050219b: Swift-BAT detection of a burst
  4. GRB 050219b: CORRECTION: Swift XRT Position
  5. GRB 050219b: Swift XRT Position
  6. GRB 050219a, optical observations
  7. GRB 050219a: Refined XRT position
  8. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  9. GRB 050219: Swift-BAT detection of a burst
  10. GRB050215b: Swift UVOT Detection of Afterglow Emission
  11. GRB 050219: Prompt X-ray position
  12. GRB 050215b: XRT confirmation of IR afterglow candidate
  13. GRB050215b: P60 Optical Observations
  14. GRB 050215b: Swift XRT Source Variability
  15. GRB 050215B: candidate afterglow
  16. GRB 050215b : Lulin follow-up observation
  17. GRB 050215b, BOOTES-2 simultaneous optical observations
  18. GRB 050215B: UKIRT K-band imaging
  19. GRB 050215b: Swift XRT Observations
  20. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  21. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  22. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  23. GRB050215B: ROTSE-III optical observations
  24. GRB050215A: ROTSE-III Optical Observations
  25. short/hard GRB 050202, optical observations
  26. GRB 050128: Radio observations
  27. Further analysis of the short Swift-BAT GRB 050202
  28. GRB 050202: Second epoch radio observations
  29. GRB050202: Radio Observations
  30. GRB 050202: Short burst detected by Swift-BAT
  31. SGR1806-20: Swift-BAT detection of a large normal burst
  32. GRB050128: Faulkes Telescope South observations
  33. GRB050128,optical observations
  34. GRB050126: Updated Swift XRT Position
  35. GRB 050126: Radio Observations
  36. GRB050128 Swift-BAT observations
  37. GRB 050128: Swift XRT prompt afterglow position
  38. GRB 050124: K-band afterglow observations
  39. GRB050126: MASTER optical limit for KECK OT
  40. GRB050126: Burst Parameters Measured by BAT
  41. GRB050126: MASTER optical observations
  42. GRB 050126: Prompt XRT detection and localization
  43. GRB050124: No Swift UVOT Detection of Afterglow Emission
  44. GRB 050117a: Radio Observations
  45. GRB050124,optical observation
  46. GRB050124: Updated Swift XRT Position and Fluxes
  47. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  48. GRB050124: Refined BAT position, spectral and fluence information
  49. GRB050124: Swift-BAT position of a double-peaked burst
  50. GRB050117a: Radio Observations
  51. GRB050117a: Refined analysis
  52. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  53. GRB050117b: Swift-BAT detection of a weak burst
  54. GRB050117: optical observation
  55. GRB 050117, I-band observations
  56. GRB 050117: Optical observation
  57. GRB050117: Refined XRT position
  58. GRB050117: MASTER optical observations
  59. MASTER:GRB050117 SWIFT
  60. GRB050117: Swift-BAT detection of a long multi-peaked burst
  61. GRB050117: Swift XRT Position
  62. SGR1806-20: Swift-BAT observations of two additional bursts
  63. SGR 1806-20, RHESSI observations of the 041227 giant flare
  64. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  65. GRB 041217: Optical observations
  66. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  67. GRB041228: ROTSE-III Optical Observations
  68. GRB041228: Swift-BAT detection of a burst
  69. GRB041219; RXTE ASM Observations
  70. NIR Observations of GRB 041219
  71. GRB041226: ROTSE-III Optical Observations
  72. GRB041226: Swift-BAT detection of a burst
  73. GRB041223: decay of the afterglow
  74. GRB041224: ROTSE-III Optical Observations
  75. GRB 041223: XRT afterglow spectrum and light curve
  76. GRB 041223 Fluence measured by Swift-BAT
  77. GRB041224: Swift-BAT detection of a soft burst
  78. GRB041223: optical and NIR observations with REM
  79. Swift-BAT Time History of GRB041219
  80. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  81. GRB041223: ROTSE-III Optical Observations
  82. GRB041223: Swift-BAT detection of a bright long burst
  83. GRB041220: Swift-BAT burst
  84. GRB 041219 Optical Observations
  85. GRB041219c: Third Burst in One Day from Swift-BAT
  86. GRB041219b: A Swift-BAT burst
  87. Swift-BAT detection of the bright long burst GRB041219
  88. GRB041217: optical limit 30 min after GRB
  89. GRB041217: Optical Observations
  90. GRB041217: NIR and optical observations with REM
  91. GRB041217: P60 Optical Observations
  92. GRB041217: Infrared Observations
  93. GRB041217: The First GRB Located On-Board Swift
  94. GRB040916: Optical observations
  95. GRB040422: optical and NIR observations at the VLT
  96. GRB040223, improved XMM position
  97. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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