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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. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  2. GRB 060928: Swift observations
  3. GRB 060928: RHESSI Spectral Fit
  4. IPN triangulation of GRB060928 (long, exceptionally bright)
  5. GRB061002: Swift UVOT followup observations
  6. GRB 060930: near-IR afterglow candidate
  7. GRB 061002: Swift-XRT Team Refined Analysis
  8. VLA observations of GRB 060926
  9. GRB061002 - SDSS Pre-Burst Observations
  10. GRB 061002, Swift-BAT refined analysis
  11. GRB061002: MASTER-VWF-Kislovodsk observations
  12. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  13. GRB 061002: Swift detection of a burst
  14. GRB 060908: Detection of a possible host
  15. GRB 060923A: Probable host galaxy in the R-band
  16. GRB 060807: Detection of a possible host galaxy
  17. GRB 060923A: VLA K-band Observations
  18. GRB060930: Faulkes Telescope South observation
  19. GRB 060930: Xinglong TNT optical observations
  20. GRB 060929: Further XRT Refined Analysis
  21. GRB 060929: Swift/UVOT Optical Observations
  22. GRB 060930: ROTSE-III Optical Limits
  23. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  24. GRB 060927 : GAO 150cm telescope optical observation
  25. GRB060929: Swift-XRT refined analysis.
  26. GRB 060929, Swift-BAT further refined analysis - late-time flare
  27. GRB 060929: TNG K-band observations
  28. GRB 060929, Swift-BAT refined analysis
  29. GRB060929: Optical limit
  30. GRB 060929: BART observation
  31. GRB 060929: MASTER-VWF-Kislovodsk observations
  32. GRB 060929: BOOTES-IR & OSN observations
  33. Liverpool Telescope observations of GRB 060929
  34. GRB 060929: Swift detection of a burst
  35. GRB060908: optical observations
  36. GRB 060729: An update on the late-time Swift observations
  37. GRB 060927: Spectroscopic redshift z=5.6
  38. IBAS Alert n.3501: not a GRB
  39. IBAS Alert n.3500: not a GRB
  40. GRB060923C: optical limit
  41. GRB060927: optical observations
  42. test of new software, grb
  43. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  44. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  45. GRB 060927: Swift/UVOT Optical Observations
  46. GRB 060927: Early color
  47. GRB 060927: Swift XRT Team refined analysis
  48. GRB 060927 optical limit
  49. GRB 060927, Swift-BAT refined analysis
  50. GRB 060927: Xinglong TNT optical observations
  51. GRB060926: improved redshift
  52. GRB 060927, optical observation
  53. GRB 060927: Possible host galaxy (star?) in the SDSS
  54. GRB 060927 : Kiso optical observation
  55. GRB060927: Faulkes Telescope South observation
  56. GRB 060926: MASTER: first minutes decay
  57. GRB060927 - SDSS Pre-Burst Observations
  58. GRB 060927: optical afterglow confirmation
  59. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  60. Swift XRT boresight
  61. GRB 060927: Swift detection of a burst
  62. GRB060926: VLT redshift
  63. GRB 060926: Swift-UVOT Detections
  64. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  65. GRB 060926: OPTIMA-Burst -- further observations
  66. GRB 060926: Swift XRT refined analysis
  67. GRB 060926, Swift-BAT refined analysis
  68. GRB 060923A: Radio Observations
  69. GRB 060926: MASTER OT alert observation
  70. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  71. GRB 060912A: Redshift of probable host galaxy
  72. GRB 060926: BOOTES-IR observations
  73. GRB 060926: Watcher observations
  74. GRB060926 OPTIMA-Burst optical observation
  75. GRB 060926: MASTER optical observation
  76. GRB 060926: Swift detection of a burst
  77. GRB 060923C, Swift-BAT refined analysis
  78. GRB 060923C: VLA Observation
  79. GRB 060923C: NIR afterglow confirmed
  80. GRB060923C: AROMA optical obsevation
  81. GRB 060923C: Gemini Observations and Afterglow Candidate
  82. GRB 060923C, optical observation
  83. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  84. GRB 060923C: VLT J-band observations
  85. GRB060923B: Swift/UVOT upper limits
  86. GRB 060923B: Swift XRT Refined Analysis
  87. GRB 060923C: Swift XRT refined analysis
  88. GRB 060923C, Swift-BAT partial refined analysis
  89. GRB 060923A: Swift XRT refined analysis
  90. GRB 060923C: Keck Observations
  91. GRB 060923A: Keck and Gemini Observations
  92. GRB 060923C: Xinglong TNT optical observations
  93. GRB 060923B, Swift-BAT refined analysis
  94. GRB060923C : Faulkes Telescope South optical limits
  95. GRB060923C: Faulkes Telescope North optical observations
  96. GRB 060923C: optical observation
  97. GRB 060923C: Swift detection of a burst
  98. GRB 060923B: Swift detection of a burst
  99. GRB 060923, Swift-BAT refined analysis
  100. GRB 060923: Early Super-LOTIS Observations

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