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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 050412 : XingLong optical observation
  2. GRB 050412: Swift-BAT refined analysis
  3. GRB 050412: ANU 2.3m observations
  4. GRB 050412: Early Optical/Ultraviolet Observations with
  5. GRB 050412: retraction of UVOT transient report
  6. GRB 050412: UVOT transient not in XRT error circle
  7. GRB 050408: SDSS Field Calibration
  8. GRB 050412: Optical limit
  9. GRB 050412: LCO Optical Observations
  10. GRB 050412: Optical observations
  11. GRB050412: P60 Observations
  12. GRB 050412: Swift XRT Position
  13. GRB050412: optical limit before and during GRB
  14. GRB 050412: LCO optical observations
  15. GRB050412: ROTSE-III Optical Limits
  16. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  17. GRB 050412: IR and Optical observations
  18. GRB 050412: IR Observations
  19. GRB050408: Radio Observations
  20. GRB 050401: Optical limit
  21. GRB 050408: Optical limit
  22. GRB050410: P60 Observations
  23. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  24. GRB 050410, optical observations
  25. GRB 050408: PROMPT VRcIc Observations
  26. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  27. GRB 050410 R band Optical Observations
  28. GRB050410 : Null detection report
  29. GRB 050410, optical observations
  30. GRB050410: Radio Observations
  31. GRB 050408: Swift XRT measurement of possible jet break
  32. GRB050410: MASTER optical observations
  33. GRB 050410: Early observations with Swift-UVOT
  34. Swift-BAT detection of GRB 050410
  35. GRB 050410: Swift XRT Position
  36. GRB 050408: Retraction of Proposed Host Galaxy
  37. GRB 050408: Inconsistency of host galaxy identification
  38. GRB 050408: Subaru Observations
  39. GRB 050408: WIDGET simultaneous optical observations
  40. GRB 050408: SOAR UBVRc Observations
  41. GRB 050408: Properties of the Host Galaxy
  42. GRB 050408: Mercator Optical Observations
  43. GRB050408: Radio Observations
  44. GRB 050408: Swift XRT analysis
  45. GRB 050408, SMARTS optical/IR afterglow observations
  46. GRB 050408: Optical limit at 20 min after the burst
  47. GRB 050408, optical observations
  48. GRB050408: REM NIR and Optical observation
  49. GRB 050408: Moderate-resolution Gemini Spectroscopy
  50. GRB 050408,optical observation
  51. GRB 050408 Optical Observations
  52. GRB 050408: Emission and absorption redshift
  53. GRB 050408: Mercator Optical Observations
  54. GRB 050408: Magellan astrometry and photometry
  55. GRB 050408: First Optical observations with TFOSC at the RTT150
  56. GRB 050408: steepening of the optical decay
  57. GRB 050408: Optical afterglow confirmed
  58. GRB 050408: opitcal observation
  59. GRB 050408, optical observations
  60. GRB 050408 optical candidate
  61. GRB 050408: Swift XRT Position
  62. GRB 050408: ROTSE-III Optical Limits
  63. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  64. GRB050408: MASTER optical observations
  65. GRB050401: Radio Detection
  66. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  67. GRB 050406: Magellan optical observations
  68. GRB 050406: early Swift XRT analysis results
  69. GRB 050406 BAT refined analysis
  70. GRB 050406: Early observations with Swift-UVOT
  71. GRB 050406: Swift XRT Position
  72. Swift-BAT detection of GRB 050406
  73. Konus-Wind observation of GRB 050401
  74. GRB050401: Radio observation at 610 MHz with GMRT
  75. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  76. GRB 050401: VLT spectroscopic redshift
  77. GRB 050401 Optical Observations
  78. GRB050401: Maidanak optical observation
  79. GRB 050401 BAT refined analysis
  80. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  81. GRB050401: TNG R-band observation
  82. GRB 050402A: IR Analysis
  83. GRB050402: XDSS counterpart
  84. GRB 050402A: IR Observations
  85. GRB 050402: Early observations with Swift-UVOT
  86. Swift Trigger 113225: P60 Observations
  87. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  88. GRB 050401: Optical afterglow confirmed
  89. GRB 050401: Optical afterglow candidate
  90. Swift-BAT detection of GRB 050401
  91. GRB 050401: Prompt XRT position
  92. Retraction of three Swift GRB triggers
  93. GRB050331: No Afterglow Detected
  94. Swift-BAT detection of GRB 050331b
  95. GRB 050331: Swift UVOT Source
  96. Swift-BAT detection of GRB 050331
  97. GRB 050331: Swift XRT Position
  98. Swift Data Publicly Available Starting April 5, 2005
  99. GRB050319: radio observation
  100. Konus-Wind observation of GRB 050326

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