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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"

5833 results found.

  1. GRB 050922C: Swift detection of a bright burst
  2. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  3. GRB050916: Swift/UVOT Upper Limits
  4. GRB 050916: XRT position
  5. GRB 050915b, SMARTS optical/IR observations of the XRT position
  6. GRB 050915a: IR Transient
  7. GRB 050915b, SMARTS optical/IR observations
  8. GRB 050915: IR Observations
  9. GRB 050915: Swift detection of a GRB
  10. GRB 050910a: TAROT early optical limits
  11. GRB 050908: Optical observations
  12. GRB050904: Optical Observations
  13. GRB 050904: TAROT optical limits
  14. GRB 050827: P200 NIR Observations
  15. GRB 050827: Optical Limit
  16. GRB050824: MASTER final analysis of the OT observations
  17. GRB050820A: RTT150 optical observations
  18. GRB050820a: PROMPT RcIc Observations
  19. GRB050815: Optical afterglow detection by Swift UVOT
  20. GRB050815: Swift XRT afterglow localization
  21. GRB050815: Swift-BAT detection of a burst
  22. GRB 050807: ROTSE-III Optical Limits
  23. GRB 050730 XMM-Newton observation
  24. GRB 050724: Chandra Observations of the X-ray Afterglow
  25. GRB050724: a short-burst detected by Swift
  26. GRB050712: optical limits
  27. GRB 050713B
  28. GRB 050713 : Planned XMM-Newton observation
  29. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  30. GRB 050701: Swift XRT afterglow position
  31. GRB050607: refined analysis of prompt REM observations
  32. GRB 050607: RAPTOR-S Early Optical Limits
  33. GRB050607: KAIT optical limits
  34. GRB 050607: Optical decay and spectral slope
  35. GRB050607,optical observation
  36. GRB 050607 - XRT refined data analysis
  37. Optical Afterglow of GRB 050607
  38. GRB050607: Swift Detection of a long GRB
  39. GRB050607: P60 Observations
  40. GRB050525: Optical observations
  41. GRB 050520: Swift XRT refined analysis
  42. XRF050509C: Chandra Afterglow Detection
  43. Swift-BAT trigger 122203 is not a real GRB
  44. GRB050502b: Early Observation
  45. GRB 050509b: Swift/UVOT follow-up measurements
  46. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  47. Swift UVOT Follow-up Observations of GRB 050509B
  48. GRB050509a: Swift UVOT observations
  49. GRB 050509b: Optical observations
  50. GRB 050505: Keck I-band Magnitude
  51. GRB 050505: early time observations
  52. GRB 050505 UVOT
  53. GRB050505: Optical Afterglow Candidate
  54. GRB 050505: Swift XRT Position
  55. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  56. GRB050502b: Afterglow Confirmation
  57. GRB 050502b, V band Observations
  58. GRB 050502a: RBO Observations
  59. GRB050502B Swift-BAT refined analysis
  60. GRB050502B: I band source in XRT error circle
  61. GRB 050502b: Swift XRT Position
  62. Swift Detection of the Bright Burst GRB050502b
  63. GRB050326: analysis of the XMM-Newton observation
  64. GRB 050416,optical observation
  65. GRB 050416: KAIT observations
  66. GRB050408: optical observation
  67. GRB 050408: Subaru Observations
  68. GRB 050408: Mercator Optical Observations
  69. GRB 050408, SMARTS optical/IR afterglow observations
  70. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  71. GRB 050402A: IR Observations
  72. GRB050331: No Afterglow Detected
  73. GRB 050331: Swift UVOT Source
  74. GRB 050331: Swift XRT Position
  75. Konus-Wind observation of GRB 050326
  76. GRB 050326 BAT refined analysis
  77. GRB050326: delayed XRT observation
  78. Swift-BAT detection of a bright GRB 050326
  79. GRB 050319: ROTSE-III Refined Analysis
  80. GRB 050319 R band observations
  81. GRB 050319: Swift-UVOT detection of the afterglow
  82. GRB050319,optical observation
  83. Swift Detection of GRB 050319
  84. GRB050223: analysis of the XMM-Newton observation
  85. GRB 050315, SMARTS optical/IR afterglow observations
  86. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  87. GRB050309: CONCAM pre-trigger and trigger coincident optical
  88. GRB 050306: optical afterglow
  89. GRB 050306: Confirmation of X-ray afterglow
  90. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  91. GRB 050306: Possible X-ray Afterglow Position from the Swift
  92. PROMPT VRcIc Observations of GRB 050223
  93. GRB 050223 Swift/BAT detection of a burst
  94. GRB 050223: Swift XRT Position
  95. GRB 050215b: XRT confirmation of IR afterglow candidate
  96. GRB 050215b: Swift XRT Source Variability
  97. GRB 050209 Optical observations
  98. GRB041219: P60 Optical Observations
  99. GRB 041218: Optical observations
  100. GRB 041016: Optical limits

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