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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"

36947 results found.

  1. IBAS Alert n.3501: not a GRB
  2. IBAS Alert n.3500: not a GRB
  3. GRB060923C: optical limit
  4. GRB060927: optical observations
  5. test of new software, grb
  6. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  7. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  8. GRB 060927: Swift/UVOT Optical Observations
  9. GRB 060927: Early color
  10. GRB 060927: Swift XRT Team refined analysis
  11. GRB 060927 optical limit
  12. GRB 060927, Swift-BAT refined analysis
  13. GRB 060927: Xinglong TNT optical observations
  14. GRB060926: improved redshift
  15. GRB 060927, optical observation
  16. GRB 060927: Possible host galaxy (star?) in the SDSS
  17. GRB 060927 : Kiso optical observation
  18. GRB060927: Faulkes Telescope South observation
  19. GRB 060926: MASTER: first minutes decay
  20. GRB060927 - SDSS Pre-Burst Observations
  21. GRB 060927: optical afterglow confirmation
  22. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  23. Swift XRT boresight
  24. GRB 060927: Swift detection of a burst
  25. GRB060926: VLT redshift
  26. GRB 060926: Swift-UVOT Detections
  27. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  28. GRB 060926: OPTIMA-Burst -- further observations
  29. GRB 060926: Swift XRT refined analysis
  30. GRB 060926, Swift-BAT refined analysis
  31. GRB 060923A: Radio Observations
  32. GRB 060926: MASTER OT alert observation
  33. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  34. GRB 060912A: Redshift of probable host galaxy
  35. GRB 060926: BOOTES-IR observations
  36. GRB 060926: Watcher observations
  37. GRB060926 OPTIMA-Burst optical observation
  38. GRB 060926: MASTER optical observation
  39. GRB 060926: Swift detection of a burst
  40. GRB 060923C, Swift-BAT refined analysis
  41. GRB 060923C: VLA Observation
  42. GRB 060923C: NIR afterglow confirmed
  43. GRB060923C: AROMA optical obsevation
  44. GRB 060923C: Gemini Observations and Afterglow Candidate
  45. GRB 060923C, optical observation
  46. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  47. GRB 060923C: VLT J-band observations
  48. GRB060923B: Swift/UVOT upper limits
  49. GRB 060923B: Swift XRT Refined Analysis
  50. GRB 060923C: Swift XRT refined analysis
  51. GRB 060923C, Swift-BAT partial refined analysis
  52. GRB 060923A: Swift XRT refined analysis
  53. GRB 060923C: Keck Observations
  54. GRB 060923A: Keck and Gemini Observations
  55. GRB 060923C: Xinglong TNT optical observations
  56. GRB 060923B, Swift-BAT refined analysis
  57. GRB060923C : Faulkes Telescope South optical limits
  58. GRB060923C: Faulkes Telescope North optical observations
  59. GRB 060923C: optical observation
  60. GRB 060923C: Swift detection of a burst
  61. GRB 060923B: Swift detection of a burst
  62. GRB 060923, Swift-BAT refined analysis
  63. GRB 060923: Early Super-LOTIS Observations
  64. GRB 060923: UKIRT nIR observations - candidate afterglow
  65. GRB060923: Faulkes Telescope North optical observations
  66. GRB060923 - SDSS Pre-Burst Observations
  67. GRB 060923: KAIT observations
  68. GRB 060923: Swift detection of a burst
  69. Swift detection of IGR J17497-2821 (trigger 230504)
  70. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  71. GRB060919: Swift/UVOT optical observations
  72. GRB 060919 : Faulkes South Telescope Observations
  73. GRB 060919, Swift-BAT refined analysis
  74. GRB060919: XRT refined analysis
  75. GRB 060919: TAROT optical observations
  76. GRB 060919: Swift detection of a burst
  77. GRB 060912A: VLA Observation
  78. GRB 060912A: Probable Host Galaxy
  79. IBAS Alert n.3470: not a GRB
  80. GRB060825: MAGIC telescope GeV observation
  81. Konus-Wind observation of GRB 060912
  82. IBAS Alert No.3468: not a GRB
  83. GRB 060912: Redshift of nearby 2MASS galaxy
  84. GRB060912: optical observations
  85. GRB 060912B: Watcher observations
  86. GRB060912: Swift/UVOT Observations
  87. GRB060912: OPTIMA-Burst optical observations
  88. GRB 060912B: a long GRB detected with INTEGRAL
  89. GRB 060912: Swift XRT Team Refined Analysis
  90. GRB 060912, Swift-BAT refined analysis
  91. GRB 060912: Correction to GCN 5559
  92. GRB 060912: Xinglong TNT optical observations
  93. GRB 060912: Swift detection of a burst with an optical afterglow
  94. VLA observations of GRB 060908
  95. GRB 060908: redshift
  96. GRB 060908, Swift/XRT refined analysis
  97. GRB 060908: Swift/UVOT Observations
  98. GRB 060908: Danish/DFOSC optical observations
  99. GRB 060908, Swift-BAT refined analysis
  100. GRB 060908 - SDSS Pre-burst Observations

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