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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 060927: optical afterglow confirmation
  2. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  3. Swift XRT boresight
  4. GRB 060927: Swift detection of a burst
  5. GRB060926: VLT redshift
  6. GRB 060926: Swift-UVOT Detections
  7. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  8. GRB 060926: OPTIMA-Burst -- further observations
  9. GRB 060926: Swift XRT refined analysis
  10. GRB 060926, Swift-BAT refined analysis
  11. GRB 060923A: Radio Observations
  12. GRB 060926: MASTER OT alert observation
  13. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  14. GRB 060912A: Redshift of probable host galaxy
  15. GRB 060926: BOOTES-IR observations
  16. GRB 060926: Watcher observations
  17. GRB060926 OPTIMA-Burst optical observation
  18. GRB 060926: MASTER optical observation
  19. GRB 060926: Swift detection of a burst
  20. GRB 060923C, Swift-BAT refined analysis
  21. GRB 060923C: VLA Observation
  22. GRB 060923C: NIR afterglow confirmed
  23. GRB060923C: AROMA optical obsevation
  24. GRB 060923C: Gemini Observations and Afterglow Candidate
  25. GRB 060923C, optical observation
  26. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  27. GRB 060923C: VLT J-band observations
  28. GRB060923B: Swift/UVOT upper limits
  29. GRB 060923B: Swift XRT Refined Analysis
  30. GRB 060923C: Swift XRT refined analysis
  31. GRB 060923C, Swift-BAT partial refined analysis
  32. GRB 060923A: Swift XRT refined analysis
  33. GRB 060923C: Keck Observations
  34. GRB 060923A: Keck and Gemini Observations
  35. GRB 060923C: Xinglong TNT optical observations
  36. GRB 060923B, Swift-BAT refined analysis
  37. GRB060923C : Faulkes Telescope South optical limits
  38. GRB060923C: Faulkes Telescope North optical observations
  39. GRB 060923C: optical observation
  40. GRB 060923C: Swift detection of a burst
  41. GRB 060923B: Swift detection of a burst
  42. GRB 060923, Swift-BAT refined analysis
  43. GRB 060923: Early Super-LOTIS Observations
  44. GRB 060923: UKIRT nIR observations - candidate afterglow
  45. GRB060923: Faulkes Telescope North optical observations
  46. GRB060923 - SDSS Pre-Burst Observations
  47. GRB 060923: KAIT observations
  48. GRB 060923: Swift detection of a burst
  49. Swift detection of IGR J17497-2821 (trigger 230504)
  50. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  51. GRB060919: Swift/UVOT optical observations
  52. GRB 060919 : Faulkes South Telescope Observations
  53. GRB 060919, Swift-BAT refined analysis
  54. GRB060919: XRT refined analysis
  55. GRB 060919: TAROT optical observations
  56. GRB 060919: Swift detection of a burst
  57. GRB 060912A: VLA Observation
  58. GRB 060912A: Probable Host Galaxy
  59. IBAS Alert n.3470: not a GRB
  60. GRB060825: MAGIC telescope GeV observation
  61. Konus-Wind observation of GRB 060912
  62. IBAS Alert No.3468: not a GRB
  63. GRB 060912: Redshift of nearby 2MASS galaxy
  64. GRB060912: optical observations
  65. GRB 060912B: Watcher observations
  66. GRB060912: Swift/UVOT Observations
  67. GRB060912: OPTIMA-Burst optical observations
  68. GRB 060912B: a long GRB detected with INTEGRAL
  69. GRB 060912: Swift XRT Team Refined Analysis
  70. GRB 060912, Swift-BAT refined analysis
  71. GRB 060912: Correction to GCN 5559
  72. GRB 060912: Xinglong TNT optical observations
  73. GRB 060912: Swift detection of a burst with an optical afterglow
  74. GRB060906: Danish/DFOSC optical observations
  75. VLA observations of GRB 060908
  76. GRB 060908: redshift
  77. GRB 060908, Swift/XRT refined analysis
  78. GRB 060908: Swift/UVOT Observations
  79. GRB 060908: Danish/DFOSC optical observations
  80. GRB 060908, Swift-BAT refined analysis
  81. GRB 060908 - SDSS Pre-burst Observations
  82. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  83. GRB 060904B: Kiso Optical observation
  84. GRB 060904A : Optical limit
  85. GRB 060908: REM optical prompt observation
  86. GRB 060908: PROMPT Detection of a Bright Counterpart
  87. GRB 060908: Swift detection of a burst with a bright optical counterpart
  88. GRB 060904A: Suzaku/WAM observation of the prompt emission
  89. GRB060906 , optical observation
  90. GRB060904b optical detections (delayed report due to internet outage)
  91. GRB 060906: optical observation
  92. GRB 060906: Early RAPTOR optical limits
  93. GRB 060906, Swift-BAT refined spectral analysis
  94. GRB 060906: Swift/XRT Refined Analysis
  95. GRB 060906: Swift-UVOT observations
  96. VLT redshift of GRB 060906
  97. GRB 060906, Swift-BAT refined analysis
  98. GRB 060906: FRAM observations - flash determination (airplane)
  99. GRB 060906: KAIT observations
  100. GRB 060906: Confirmation of P60 Optical Afterglow

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