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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"

18400 results found.

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

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