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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').
  1. GRB 061007: Swift XRT refined analysis
  2. GRB 061006: Swift/UVOT optical observations
  3. Konus-Wind observation of the short hard GRB 061006
  4. GRB 061007 - FTS early brightening and power law decay
  5. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  6. GRB 061007: Swift detection of a burst with an optical counterpart
  7. GRB 061007: ROTSE-III Detection of Optical Counterpart
  8. GRB 061006: VLT observation
  9. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  10. GRB 061006: Swift-XRT Team Refined Analysis
  11. GRB061006 (Swift 232585) might be a short-hard GRB
  12. GRB 060930: near-IR afterglow candidate retraction
  13. GRB061006: Faulkes Telescope South Observations
  14. GRB 061006: Swift detection of a burst
  15. GRB 061004: Optical afterglow candidate and redshift
  16. GRB 061004: Las Campanas Optical/NIR Observations
  17. GRB061004: Swift/UVOT optical observations
  18. GRB 061004: Swift-XRT Team Refined Analysis
  19. GRB 061004, Swift BAT refined analysis
  20. GRB 061004: Nearby 2MASS Galaxy
  21. GRB 060928: Correction to GCN 5690
  22. GRB 061004: Swift detection of a burst
  23. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  24. Konus-Wind observation of GRB 060928
  25. GRB 060928: Suzaku/WAM observation of the prompt emission
  26. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  27. GRB 060928: Swift observations
  28. GRB 060928: RHESSI Spectral Fit
  29. IPN triangulation of GRB060928 (long, exceptionally bright)
  30. GRB061002: Swift UVOT followup observations
  31. GRB 060930: near-IR afterglow candidate
  32. GRB 061002: Swift-XRT Team Refined Analysis
  33. VLA observations of GRB 060926
  34. GRB061002 - SDSS Pre-Burst Observations
  35. GRB 061002, Swift-BAT refined analysis
  36. GRB061002: MASTER-VWF-Kislovodsk observations
  37. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  38. GRB 061002: Swift detection of a burst
  39. GRB 060908: Detection of a possible host
  40. GRB 060923A: Probable host galaxy in the R-band
  41. GRB 060807: Detection of a possible host galaxy
  42. GRB 060923A: VLA K-band Observations
  43. GRB060930: Faulkes Telescope South observation
  44. GRB 060930: Xinglong TNT optical observations
  45. GRB 060929: Further XRT Refined Analysis
  46. GRB 060929: Swift/UVOT Optical Observations
  47. GRB 060930: ROTSE-III Optical Limits
  48. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  49. GRB 060927 : GAO 150cm telescope optical observation
  50. GRB060929: Swift-XRT refined analysis.
  51. GRB 060929, Swift-BAT further refined analysis - late-time flare
  52. GRB 060929: TNG K-band observations
  53. GRB 060929, Swift-BAT refined analysis
  54. GRB060929: Optical limit
  55. GRB 060929: BART observation
  56. GRB 060929: MASTER-VWF-Kislovodsk observations
  57. GRB 060929: BOOTES-IR & OSN observations
  58. Liverpool Telescope observations of GRB 060929
  59. GRB 060929: Swift detection of a burst
  60. GRB060908: optical observations
  61. GRB 060729: An update on the late-time Swift observations
  62. GRB 060927: Spectroscopic redshift z=5.6
  63. IBAS Alert n.3501: not a GRB
  64. IBAS Alert n.3500: not a GRB
  65. GRB060923C: optical limit
  66. GRB060927: optical observations
  67. test of new software, grb
  68. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  69. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  70. GRB 060927: Swift/UVOT Optical Observations
  71. GRB 060927: Early color
  72. GRB 060927: Swift XRT Team refined analysis
  73. GRB 060927 optical limit
  74. GRB 060927, Swift-BAT refined analysis
  75. GRB 060927: Xinglong TNT optical observations
  76. GRB060926: improved redshift
  77. GRB 060927, optical observation
  78. GRB 060927: Possible host galaxy (star?) in the SDSS
  79. GRB 060927 : Kiso optical observation
  80. GRB060927: Faulkes Telescope South observation
  81. GRB 060926: MASTER: first minutes decay
  82. GRB060927 - SDSS Pre-Burst Observations
  83. GRB 060927: optical afterglow confirmation
  84. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  85. Swift XRT boresight
  86. GRB 060927: Swift detection of a burst
  87. GRB060926: VLT redshift
  88. GRB 060926: Swift-UVOT Detections
  89. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  90. GRB 060926: OPTIMA-Burst -- further observations
  91. GRB 060926: Swift XRT refined analysis
  92. GRB 060926, Swift-BAT refined analysis
  93. GRB 060923A: Radio Observations
  94. GRB 060926: MASTER OT alert observation
  95. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  96. GRB 060912A: Redshift of probable host galaxy
  97. GRB 060926: BOOTES-IR observations
  98. GRB 060926: Watcher observations
  99. GRB060926 OPTIMA-Burst optical observation
  100. GRB 060926: MASTER optical observation

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