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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

26038 results found.

  1. GRB 050128: Swift XRT prompt afterglow position
  2. GRB 050124: K-band afterglow observations
  3. GRB050126: MASTER optical limit for KECK OT
  4. GRB050126: Burst Parameters Measured by BAT
  5. GRB050126: MASTER optical observations
  6. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  7. GRB 050126: Prompt XRT detection and localization
  8. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  9. GRB050124: No Swift UVOT Detection of Afterglow Emission
  10. GRB 050117a: Radio Observations
  11. GRB 050124: NIR Candidates from Keck/NIRC
  12. GRB050124,optical observation
  13. GRB050124: Updated Swift XRT Position and Fluxes
  14. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  15. GRB050124: Refined BAT position, spectral and fluence information
  16. GRB050124: Swift-BAT position of a double-peaked burst
  17. Unusual optical transient (GRB ???)
  18. GRB050117a: Radio Observations
  19. GRB050117a: Refined analysis
  20. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  21. GRB050117: Palomar WIRC Ks-band observations
  22. GRB050117b: Swift-BAT detection of a weak burst
  23. GRB050117: optical observation
  24. GRB 050117, I-band observations
  25. GRB 050117: Optical observation
  26. GRB050117: Refined XRT position
  27. GRB050117: MASTER optical observations
  28. MASTER:GRB050117 SWIFT
  29. GRB050117: Swift-BAT detection of a long multi-peaked burst
  30. GRB050117: Swift XRT Position
  31. SGR1806-20: Swift-BAT observations of two additional bursts
  32. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  33. SGR 1806-20: Temporal and Spectral behavior of radio transient
  34. SGR 1806-20, RHESSI observations of the 041227 giant flare
  35. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  36. GRB 041217: Optical observations
  37. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  38. GRB041219, early time observations
  39. GRB041228: ROTSE-III Optical Observations
  40. GRB041228: Swift-BAT detection of a burst
  41. GRB041219; RXTE ASM Observations
  42. NIR Observations of GRB 041219
  43. GRB041226: ROTSE-III Optical Observations
  44. GRB041226: Swift-BAT detection of a burst
  45. GRB041223: decay of the afterglow
  46. GRB041224: ROTSE-III Optical Observations
  47. GRB 041223: XRT afterglow spectrum and light curve
  48. GRB 041223 Fluence measured by Swift-BAT
  49. GRB041224: Swift-BAT detection of a soft burst
  50. GRB041223: optical and NIR observations with REM
  51. Swift-BAT Time History of GRB041219
  52. GRB 041223: J-band observations of the afterglow
  53. GRB 041223: Detection of Optical Transient with LCO40
  54. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  55. GRB041223: ROTSE-III Optical Observations
  56. GRB041223: Swift-BAT detection of a bright long burst
  57. GRB 041218: optical observations
  58. GRB 041219: WSRT Radio Afterglow Detection
  59. GRB 041219 : optical follow-up observations
  60. GRB041220: Swift-BAT burst
  61. GRB 041219 Optical Observations
  62. GRB041219c: Third Burst in One Day from Swift-BAT
  63. GRB041219: Optical Afterglow Detection
  64. GRB041219: Continued NIR Observations
  65. GRB041219b: A Swift-BAT burst
  66. GRB 041219: Radio Afterglow Detection
  67. GRB 041218 : Radio Observations
  68. GRB 041218: R-band optical observations
  69. GRB041218: Liverpool Telescope optical observations
  70. GRB041218: optical observations
  71. GRB041219: Confirmed NIR Afterglow
  72. GRB041218: Continued P60 Optical Observations
  73. Swift-BAT detection of the bright long burst GRB041219
  74. GRB 041219: Infrared Afterglow Candidate
  75. GRB 041219: Infrared Afterglow Candidate
  76. GRB041218, BVRcIc field calibration
  77. GRB041218: optical observations
  78. GRB041217: optical limit 30 min after GRB
  79. GRB 041218: Optical observations
  80. GRB041217: Optical Observations
  81. GRB041217: NIR and optical observations with REM
  82. GRB041217: P60 Optical Observations
  83. GRB041217: Infrared Observations
  84. GRB041217: The First GRB Located On-Board Swift
  85. Optical transient (GRB?) in Lynx
  86. GRB041211, BVRcIc field calibration
  87. GRB041211: P60 optical imaging
  88. GRB970815: Discovery of Optical Afterglow
  89. GRB 040924: Afterglow Color
  90. GRB 041006: GETS Optical Afterglow Observation
  91. GRB 041006: Optical Observations
  92. GRB041006, late-time optical photometry
  93. GRB041006: RTT150 Optical Observations
  94. HST Observations: XRF 040701 and 040812
  95. GRB041006: RTT150 Optical Observations
  96. GRB 041016: Optical limits
  97. GRB041006: Near Infrared observations
  98. GRB040924, BVRcIc field calibration
  99. GRB041006: Fading X-ray Afterglow Observed with Chandra
  100. GRB041006: VLT observations of the afterglow and host galaxy

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