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

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