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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 060923A: Radio Observations
  2. GRB 060926: MASTER OT alert observation
  3. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  4. GRB 060912A: Redshift of probable host galaxy
  5. GRB 060926: BOOTES-IR observations
  6. GRB 060926: Watcher observations
  7. GRB060926 OPTIMA-Burst optical observation
  8. GRB 060926: MASTER optical observation
  9. GRB 060926: Swift detection of a burst
  10. GRB 060923C, Swift-BAT refined analysis
  11. GRB 060923C: VLA Observation
  12. GRB 060923C: NIR afterglow confirmed
  13. GRB060923C: AROMA optical obsevation
  14. GRB 060923C: Gemini Observations and Afterglow Candidate
  15. GRB 060923C, optical observation
  16. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  17. GRB 060923C: VLT J-band observations
  18. GRB060923B: Swift/UVOT upper limits
  19. GRB 060923B: Swift XRT Refined Analysis
  20. GRB 060923C: Swift XRT refined analysis
  21. GRB 060923C, Swift-BAT partial refined analysis
  22. GRB 060923A: Swift XRT refined analysis
  23. GRB 060923C: Keck Observations
  24. GRB 060923A: Keck and Gemini Observations
  25. GRB 060923C: Xinglong TNT optical observations
  26. GRB 060923B, Swift-BAT refined analysis
  27. GRB060923C : Faulkes Telescope South optical limits
  28. GRB060923C: Faulkes Telescope North optical observations
  29. GRB 060923C: optical observation
  30. GRB 060923C: Swift detection of a burst
  31. GRB 060923B: Swift detection of a burst
  32. GRB 060923, Swift-BAT refined analysis
  33. GRB 060923: Early Super-LOTIS Observations
  34. GRB 060923: UKIRT nIR observations - candidate afterglow
  35. GRB060923: Faulkes Telescope North optical observations
  36. GRB060923 - SDSS Pre-Burst Observations
  37. GRB 060923: KAIT observations
  38. GRB 060923: Swift detection of a burst
  39. Swift detection of IGR J17497-2821 (trigger 230504)
  40. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  41. GRB060919: Swift/UVOT optical observations
  42. GRB 060919 : Faulkes South Telescope Observations
  43. GRB 060919, Swift-BAT refined analysis
  44. GRB060919: XRT refined analysis
  45. GRB 060919: TAROT optical observations
  46. GRB 060919: Swift detection of a burst
  47. GRB 060912A: VLA Observation
  48. GRB 060912A: Probable Host Galaxy
  49. IBAS Alert n.3470: not a GRB
  50. GRB060825: MAGIC telescope GeV observation
  51. Konus-Wind observation of GRB 060912
  52. IBAS Alert No.3468: not a GRB
  53. GRB 060912: Redshift of nearby 2MASS galaxy
  54. GRB060912: optical observations
  55. GRB 060912B: Watcher observations
  56. GRB060912: Swift/UVOT Observations
  57. GRB060912: OPTIMA-Burst optical observations
  58. GRB 060912B: a long GRB detected with INTEGRAL
  59. GRB 060912: Swift XRT Team Refined Analysis
  60. GRB 060912, Swift-BAT refined analysis
  61. GRB 060912: Correction to GCN 5559
  62. GRB 060912: Xinglong TNT optical observations
  63. GRB 060912: Swift detection of a burst with an optical afterglow
  64. GRB060906: Danish/DFOSC optical observations
  65. VLA observations of GRB 060908
  66. GRB 060908: redshift
  67. GRB 060908, Swift/XRT refined analysis
  68. GRB 060908: Swift/UVOT Observations
  69. GRB 060908: Danish/DFOSC optical observations
  70. GRB 060908, Swift-BAT refined analysis
  71. GRB 060908 - SDSS Pre-burst Observations
  72. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  73. GRB 060904B: Kiso Optical observation
  74. GRB 060904A : Optical limit
  75. GRB 060908: REM optical prompt observation
  76. GRB 060908: PROMPT Detection of a Bright Counterpart
  77. GRB 060908: Swift detection of a burst with a bright optical counterpart
  78. GRB 060904A: Suzaku/WAM observation of the prompt emission
  79. GRB060906 , optical observation
  80. GRB060904b optical detections (delayed report due to internet outage)
  81. GRB 060906: optical observation
  82. GRB 060906: Early RAPTOR optical limits
  83. GRB 060906, Swift-BAT refined spectral analysis
  84. GRB 060906: Swift/XRT Refined Analysis
  85. GRB 060906: Swift-UVOT observations
  86. VLT redshift of GRB 060906
  87. GRB 060906, Swift-BAT refined analysis
  88. GRB 060906: FRAM observations - flash determination (airplane)
  89. GRB 060906: KAIT observations
  90. GRB 060906: Confirmation of P60 Optical Afterglow
  91. GRB 060906: observations with FRAM
  92. GRB 060906 (?): P60 Optical Afterglow Candidate
  93. GRB 060906: Swift detection of a probable burst
  94. GRB 060904A Milagro GeV/TeV Observations
  95. GRB060904b, optical observations
  96. GRB 060904b: SMARTS optical/IR afterglow observations
  97. GRB 060904B: RTT150 optical observations
  98. GRB060904A: Swift/UVOT optical observations
  99. GRB 060904A: Subaru NIR observation
  100. GRB 060904A: pseudo-z from spectral parameters of the prompt emission

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