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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 060813: Swift/BAT, Konus-Wind, and Suzaku/WAM joint prompt spectral analysis
  2. GRB060825: Liverpool Telescope optical observations
  3. GRB 060825: TNG optical observations
  4. GRB 060825: TAROT optical observations
  5. GRB 060825: P60 Observations
  6. GRB060825: BOOTES-IR optical observations
  7. GRB 060825: Swift detection of a burst
  8. GRB060801: host galaxy redshift
  9. GRB060729: analysis of XMM-Newton observation
  10. GRB 060814: pseudo-z from spectral parameters of the prompt
  11. IBAS Alerts No 3429 and 3430: not GRBs
  12. Radio observations of GRB 060719
  13. GRB 060729, SMARTS optical/IR observations
  14. GRB060814: Break in the XRT light curve
  15. GRB060813: Break in the XRT light curve
  16. GRB 060813: A long, bright GRB detected with Suzaku WAM
  17. GRB 060814: Confirmation of IR afterglow
  18. Konus-Wind observation of GRB 060814
  19. GRB 060814: Refined analysis of the Swift-BAT burst
  20. GRB 060814: P60 Observations
  21. GRB 060814: P200 NIR Observations
  22. GRB 060814: source inside revised XRT error box
  23. GRB 060814: Possible IR counterpart
  24. GRB060805B: optical observations
  25. GRB060814: Swift/UVOT upper limits
  26. GRB 060813: pseudo-z from spectral parameters of the prompt
  27. GRB 060814: Swift XRT refined analysis
  28. GRB 060814: VLT optical limits
  29. GRB 060814 - SDSS Pre-Burst Observations
  30. GRB 060814: TAROT optical observations
  31. GRB 060814: Swift detection of a bright burst
  32. Konus-Wind observation of GRB 060813
  33. GRB060813: Swift/UVOT upper limits
  34. GRB 060813: Swift XRT refined analysis
  35. GRB 060813: Refined analysis of the Swift-BAT burst
  36. GRB 060813: Swift detection of a burst
  37. GRB051109B: Late-time Radio Observations
  38. Image of the dust-scattering halo around SGR 1806-20
  39. Second VLA limit on new radio point source in SGR 1806-20
  40. A dust-scattering halo detected around SGR 1806-20
  41. GRB 060805B: pseudo-z from spectral parameters of the prompt emission
  42. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  43. GRB060807: Possible Highly Significant X-ray Emission Lines
  44. GRB060714: optical observations
  45. IBAS Alert n. 3422: not a GRB
  46. GRB 060729: An update on the Swift XRT and UVOT observations
  47. GRB060717: optical observations
  48. GRB060807: Optical limiting magnitudes
  49. GRB 060805B: optical observation at Sierra Nevada
  50. GRB 060805B: XRT Team Analysis
  51. VLA Upper Limit on Outburst of SGR 1806-20
  52. GRB060806 is similar to previous activity of SGR1806-20
  53. GRB 060807: UVOT Upper limits
  54. GRB 060807: afterglow confirmation
  55. GRB 060807: XRT Team refined analysis
  56. GRB 060807: K- and R-band observations
  57. GRB 060807: Refined analysis of the Swift-BAT burst
  58. GRB060807: optical afterglow candidate
  59. GRB060806 = SGR1806-20
  60. GRB 060805B: RHESSI Spectral Fit
  61. GRB060807: optical upper limit in white light
  62. IPN triangulation of GRB060806 (long, exceptionally bright)
  63. GRB060807 - SDSS Pre-burst Observations
  64. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  65. GRB 060805B: Swift/UVOT Upper Limits
  66. GRB 060807, optical observation
  67. GRB 060807: Kanazawa R-band observation
  68. GRB 060807: optical limit
  69. GRB 060807: Swift detection of a burst
  70. GRB 060801: Second Epoch WSRT Radio Observations
  71. IPN triangulation of GRB060805B
  72. GRB060805 Liverpool Telescope observations
  73. GRB 060805: optical upper limit in R
  74. GRB 060805: XRT Team Refined Analysis
  75. GRB 060805: Swift-BAT Refined Analysis
  76. GRB 060805: Swift/UVOT Upper Limits
  77. GRB 060805: P60 Observations
  78. GRB 060805: KAIT observations
  79. GRB 060805 - SDSS Pre-Burst Observations
  80. GRB 060805: Swift detection of a burst
  81. GRB 060804: Swift UVOT observations
  82. GRB 060804: Swift-XRT Team Refined Analysis
  83. GRB 060804: Refined analysis of the Swift-BAT burst
  84. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  85. GRB 060728: Upper limits of the X-ray emission
  86. GRB 060801: no variability of optical sources
  87. IBAS Alert 3418: not a GRB
  88. GRB 060801: WSRT Radio Observations
  89. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  90. GRB060801: Radio Observations
  91. GRB 051109B: Bright spiral host galaxy at low redshift
  92. GRB 060801: optical observations at FORS2/VLT
  93. GRB060801: Swift/UVOT Upper Limits
  94. GRB 060801: optical observations at Hanle and Calar Alto
  95. GRB060801: optical upper limit in R
  96. GRB 060801: Swift XRT refined analysis
  97. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  98. GRB 060801, optical observation
  99. GRB 060801: Kanazawa Optical Observation
  100. GRB 060801: Swift detection of a short burst

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