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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"

23689 results found.

  1. GRB 050509b: RAPTOR deep, early limits.
  2. GRB 050509b: Swift/UVOT follow-up measurements
  3. GRB 050509a: Swift-BAT refined analysis
  4. GRB 050509c: ROTSE-III Optical Limits
  5. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  6. Swift UVOT Follow-up Observations of GRB 050509B
  7. GRB 050509B: Swift/XRT refined analysis
  8. GRB 050509b: Possible Optical Counterpart
  9. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  10. GRB 050509b: optical observations
  11. GRB 050509B: ROTSE-III Optical Limits
  12. GRB 050505: Keck I-band Magnitude
  13. GRB 050505: early time observations
  14. GRB 050505, simultaneous optical observation
  15. GRB050505: Infrared observations
  16. GRB 050505: Further Swift UVOT observations.
  17. GRB050505: AAVSO observations
  18. GRB 050416b:Swift XRT afterglow upper limits
  19. GRB 050416b:Swift XRT afterglow upper limits
  20. Swift UVOT observation of GRB 050504
  21. GRB 050504, R band Observations
  22. GRB 050504: A long GRB detected with INTEGRAL
  23. GRB (?) 050504: IR Observations, Intriguing Source
  24. Renewal of SGR 1806-20 activity
  25. GRB 050502a: RBO Observations
  26. GRB050502B Swift-BAT refined analysis
  27. Swift UVOT refined analysis
  28. GRB050502B: Optical Limits from ANU 1m
  29. Swift Detection of the Bright Burst GRB050502b
  30. GRB 050502: INTEGRAL results
  31. GRB 050502 - A long GRB detected with INTEGRAL
  32. GRB 050502: ROTSE-III Detection of Possible Counterpart
  33. Swift-BAT Trigger 115881 is not a real GRB
  34. Swift/BAT possible detection of a weak burst GRB050430
  35. GRB 050422: Swift-UVOT observation
  36. GRB 050422: Swift-BAT refined analysis
  37. Swift Detection of GRB 050422
  38. GRB 050421: Swift-UVOT observation
  39. GRB 050421: IR Observations
  40. GRB 050421: Swift-BAT refined analysis
  41. GRB 050421: ROTSE-III Optical Limits
  42. GRB 050421: NIR observations
  43. GRB 050416b: Tentative Swift XRT Position
  44. GRB 050315: potential host galaxy
  45. GRB050326: analysis of the XMM-Newton observation
  46. GRB050418: Null Optical Observations
  47. GRB 050412: Chandra observations
  48. GRB 050418: Swift-BAT refined analysis
  49. GRB 050416b: Swift-BAT refined analysis
  50. GRB 050416: Swift/UVOT refined analysis
  51. IBAS GRB Alert # 2463: not a GRB
  52. GRB050416: Maidanak optical observations
  53. GRB 050416,optical observation
  54. Swift BAT/XRT Detection of GRB 050416
  55. GRB050408: optical observation
  56. GRB 050412: PROMPT VRcIc Observations
  57. GRB 050412: Swift-BAT refined analysis
  58. GRB 050412: LCO Optical Observations
  59. GRB050412: P60 Observations
  60. GRB 050410, optical observations
  61. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  62. GRB 050410 R band Optical Observations
  63. GRB050410 : Null detection report
  64. GRB 050408: Swift XRT measurement of possible jet break
  65. GRB050410: MASTER optical observations
  66. GRB 050410: Early observations with Swift-UVOT
  67. Swift-BAT detection of GRB 050410
  68. GRB 050408: WIDGET simultaneous optical observations
  69. GRB 050408: Properties of the Host Galaxy
  70. GRB 050408: Swift XRT analysis
  71. GRB 050408, optical observations
  72. GRB050408: REM NIR and Optical observation
  73. GRB 050408,optical observation
  74. GRB 050408 Optical Observations
  75. GRB 050408: Mercator Optical Observations
  76. GRB 050408: ROTSE-III Optical Limits
  77. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  78. GRB050408: MASTER optical observations
  79. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  80. GRB 050406: early Swift XRT analysis results
  81. GRB 050406 BAT refined analysis
  82. GRB 050406: Early observations with Swift-UVOT
  83. GRB050401: Radio observation at 610 MHz with GMRT
  84. GRB050401: Maidanak optical observation
  85. GRB 050401 BAT refined analysis
  86. GRB050401: TNG R-band observation
  87. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  88. Swift-BAT detection of GRB 050401
  89. GRB050331: No Afterglow Detected
  90. GRB 050331: Swift UVOT Source
  91. Konus-Wind observation of GRB 050326
  92. GRB050326: optical limit
  93. GRB 050326: Early observations with Swift-UVOT
  94. GRB 050326 BAT refined analysis
  95. Swift-BAT detection of a bright GRB 050326
  96. GRB050319: optical observation, March 20-22
  97. Swift-BAT trigger 112060 is not a real GRB
  98. GRB 050319: ROTSE-III Refined Analysis
  99. GRB 050318: Swift-BAT refined analysis
  100. GRB 050319: Swift-UVOT detection of the afterglow

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