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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"
  1. GRB 050416 : optical observation at Xinglong observatory
  2. GRB 050416B: optical observations
  3. GRB 050416b: Swift-BAT refined analysis
  4. GRB 050416b: LCO observations
  5. GRB 050416b: LCO observations
  6. GRB050416B: IR observations
  7. GRB 050416: Swift/UVOT refined analysis
  8. Swift-BAT detection of GRB 050416b
  9. IBAS GRB Alert # 2463: not a GRB
  10. GRB050412: Radio Observations
  11. GRB 050416: Swift/UVOT detection of afterglow emission
  12. GRB050416: Refined Swift-XRT analysis
  13. GRB050416: Maidanak optical observations
  14. GRB 050416: Swift-BAT refined analysis
  15. GRB 050416: ART observations
  16. GRB 050416,optical observation
  17. GRB 050416: KAIT observations
  18. GRB050416: P200 NIR Observations
  19. GRB 050416: Swift XRT Position
  20. GRB 050416: Radio observations
  21. Confirmation of OT for GRB050416
  22. GRB050416: P60 Afterglow Candidate
  23. Swift BAT/XRT Detection of GRB 050416
  24. GRB 050412: Subaru observations
  25. GRB 050408: RTT150 optical observations
  26. GRB050408: optical observation
  27. GRB 050412: PROMPT VRcIc Observations
  28. GRB 050408: Kuiper 1.5m observations
  29. GRB 050412: optical limit
  30. GRB 050412: optical observations
  31. GRB 050408: refined XRT analysis, no jet break seen yet
  32. GRB 050412: early Swift XRT analysis results
  33. GRB 050412 : XingLong optical observation
  34. GRB 050412: Swift-BAT refined analysis
  35. GRB 050412: ANU 2.3m observations
  36. GRB 050412: Early Optical/Ultraviolet Observations with
  37. GRB 050412: retraction of UVOT transient report
  38. GRB 050412: UVOT transient not in XRT error circle
  39. GRB 050408: SDSS Field Calibration
  40. GRB 050412: Optical limit
  41. GRB 050412: LCO Optical Observations
  42. GRB 050412: Optical observations
  43. GRB050412: P60 Observations
  44. GRB 050412: Swift XRT Position
  45. GRB050412: optical limit before and during GRB
  46. GRB 050412: LCO optical observations
  47. GRB050412: ROTSE-III Optical Limits
  48. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  49. GRB 050412: IR and Optical observations
  50. GRB 050412: IR Observations
  51. GRB050408: Radio Observations
  52. GRB 050401: Optical limit
  53. GRB 050408: Optical limit
  54. GRB050410: P60 Observations
  55. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  56. GRB 050410, optical observations
  57. GRB 050408: PROMPT VRcIc Observations
  58. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  59. GRB 050410 R band Optical Observations
  60. GRB050410 : Null detection report
  61. GRB 050410, optical observations
  62. GRB050410: Radio Observations
  63. GRB 050408: Swift XRT measurement of possible jet break
  64. GRB050410: MASTER optical observations
  65. GRB 050410: Early observations with Swift-UVOT
  66. Swift-BAT detection of GRB 050410
  67. GRB 050410: Swift XRT Position
  68. GRB 050408: Retraction of Proposed Host Galaxy
  69. GRB 050408: Inconsistency of host galaxy identification
  70. GRB 050408: Subaru Observations
  71. GRB 050408: WIDGET simultaneous optical observations
  72. GRB 050408: SOAR UBVRc Observations
  73. GRB 050408: Properties of the Host Galaxy
  74. GRB 050408: Mercator Optical Observations
  75. GRB050408: Radio Observations
  76. GRB 050408: Swift XRT analysis
  77. GRB 050408, SMARTS optical/IR afterglow observations
  78. GRB 050408: Optical limit at 20 min after the burst
  79. GRB 050408, optical observations
  80. GRB050408: REM NIR and Optical observation
  81. GRB 050408: Moderate-resolution Gemini Spectroscopy
  82. GRB 050408,optical observation
  83. GRB 050408 Optical Observations
  84. GRB 050408: Emission and absorption redshift
  85. GRB 050408: Mercator Optical Observations
  86. GRB 050408: Magellan astrometry and photometry
  87. GRB 050408: First Optical observations with TFOSC at the RTT150
  88. GRB 050408: steepening of the optical decay
  89. GRB 050408: Optical afterglow confirmed
  90. GRB 050408: opitcal observation
  91. GRB 050408, optical observations
  92. GRB 050408 optical candidate
  93. GRB 050408: Swift XRT Position
  94. GRB 050408: ROTSE-III Optical Limits
  95. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  96. GRB050408: MASTER optical observations
  97. GRB050401: Radio Detection
  98. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  99. GRB 050406: Magellan optical observations
  100. GRB 050406: early Swift XRT analysis results

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