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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"

3041 results found.

  1. GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
  2. GRB 100413A: Swift-XRT Refined Analysis
  3. Spin down rate and inferred dipole magnetic field of the new soft gamma-ray repeater SGR 1833-0832
  4. Swift/BAT trigger 417974 (GRB100401A): Swift/XRT observations
  5. GRB 100316A: R-band limit
  6. GRB 100331B: Swift/XRT possible afterglow candidate
  7. SGR 1833-0832: Archival Chandra Observations
  8. Possible pulsation period in SGR 1833-0832
  9. Discovery of the Spin Period of SGR 1833-0832
  10. Probable SGR 1833-0832: Swift-XRT refined analysis
  11. Swift-XRT refined position of the probable new SGR 1833-0832
  12. GRB 100316D: Swift XRT enhanced position and further refined analysis
  13. GRB 100316B: Swift-XRT refined analysis
  14. GRB 100316C: Swift-XRT team refined analysis
  15. GRB 100316A: Swift-XRT refined analysis
  16. GRB 100305A: Swift-XRT refined analysis
  17. GRB 100305A: PAIRITEL NIR Upper Limits
  18. GRB 100302A: Swift-XRT refined analysis
  19. GRB 100219A: XRT refined analysis
  20. GRB 100216A: Swift/UVOT Observations
  21. GRB 100216A: XRT Refined Analysis
  22. GRB 100213B: PAIRITEL NIR Upper Limits
  23. GRB 100213B: Swift XRT refined analysis
  24. GRB 100212A: Swift XRT refined analysis
  25. GRB 100206A: PAIRITEL Photometry of Host Candidate
  26. GRB 100206A: NOT NIR observations
  27. GRB 100206A: Swift-XRT refined analysis
  28. GRB 100205A: Swift XRT refined analysis
  29. GRB 100203A: Swift XRT and UVOT refined analyses
  30. GRB 100115A: Swift-XRT refined analysis
  31. GRB 100117A: Swift-XRT refined analysis
  32. GRB 100115A: Swift-XRT candidate afterglow
  33. GRB 100111A: PAIRITEL NIR Upper Limits
  34. GRB 100103A: Swift-XRT team refined analysis
  35. GRB 100103A: Swift/XRT position
  36. Swift Trigger 381591 is probably not a burst
  37. GRB 091230: Swift-XRT observation
  38. Swift Trigger 381434 is not a GRB
  39. GRB 091221 : IRSF NIR upper limit
  40. GRB 091117: Swift-XRT late time observations
  41. GRB 091221: Swift-XRT refined analysis
  42. GRB 091221: Enhanced Swift-XRT position
  43. Swift trigger 379449 (possible GRB) is not a burst
  44. GRB091208A: Swift/UVOT refined analysis
  45. GRB 091208A: Swift-XRT observations
  46. GRB 091208B: Swift-XRT refined analysis
  47. GRB091202: Swift-XRT refined analysis
  48. Konus-Wind observation of very long GRB 091123
  49. GRB 091130B: Swift-XRT team refined analysis
  50. Swift trigger 377436 (possible GRB 091130A) is not a burst
  51. GRB 091127: Swift-XRT afterglow detection and analysis
  52. GRB 091117: Swift-XRT observations
  53. GRB 091117: Evidence for Variability of XRT Source #1
  54. GRB 091117: Swift XRT refined analysis
  55. GRB091111: Swift XRT refined analysis
  56. GRB 091109B: Swift-XRT Team refined analysis
  57. GRB 091109: Swift-XRT refined analysis
  58. GRB 091104: Swift XRT Refined Analysis
  59. GRB091026 : IRSF NIR upper limit
  60. GRB 091102: Swift-XRT refined analysis
  61. GRB 091026: Swift-XRT refined analysis
  62. GRB 091024: Swift-XRT team refined analysis
  63. GRB 091020: Swift-XRT refined analysis
  64. GRB 091018: Swift XRT refined analysis
  65. GRB 091018: miniTAO/ANIR Observations
  66. GRB 091010: Swift-XRT refined analysis
  67. GRB 091010: Swift-XRT position
  68. GRB 091003: Swift-XRT confirmation of fading afterglow
  69. GRB 091003: Swift XRT analysis
  70. GRB 090929A: Swift-XRT non-detection
  71. GRB 090929B: Swift-XRT refined analysis
  72. GRB090926A: Swift-XRT refined analysis
  73. GRB090904B : IRSF NIR upper limit
  74. GRB 090916: Swift-XRT upper limit
  75. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  76. GRB 090827: Confirmation of the X-ray afterglow
  77. GRB 090912: Swift-XRT refined analysis
  78. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  79. GRB 090904A: Swift-XRT refined analysis
  80. GRB 090904B: Swift XRT Refined Analysis
  81. GRB 090904A: Enhanced Swift XRT position
  82. GRB090902B: Swift XRT refined analysis
  83. GRB 090902B: Enhanced Swift-XRT position
  84. Swift Trigger 361477, called GRB090831B, is probably not real.
  85. GRB 090831C: Swift XRT Refined Analysis
  86. GRB 090827: Swift XRT and UVOT observations
  87. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  88. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  89. GRB 090817: Confirmation of the X-ray afterglow
  90. GRB 090815C: Swift refined analysis
  91. GRB 090817: Swift-XRT observations
  92. GRB 090814B: Confirmation of the X-ray afterglow
  93. GRB 090814B: Swift/UVOT Upper Limits
  94. GRB 090814B: Swift-XRT detection of a possible afterglow.
  95. GRB 090814A: Swift-XRT Team Refined Analysis
  96. GRB 090813: Swift-XRT refined analysis
  97. GRB 090812: Swift XRT refined analysis
  98. GRB 090809: Swift-XRT refined analysis
  99. GRB 090807: Swift-XRT refined analysis
  100. GRB 090728: Swift XRT refined analysis

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