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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 060729, SMARTS optical/IR observations
  2. GRB060814: Break in the XRT light curve
  3. GRB060813: Break in the XRT light curve
  4. GRB 060813: A long, bright GRB detected with Suzaku WAM
  5. GRB 060814: Confirmation of IR afterglow
  6. Konus-Wind observation of GRB 060814
  7. GRB 060814: Refined analysis of the Swift-BAT burst
  8. GRB 060814: P60 Observations
  9. GRB 060814: P200 NIR Observations
  10. GRB 060814: source inside revised XRT error box
  11. GRB 060814: Possible IR counterpart
  12. GRB060805B: optical observations
  13. GRB060814: Swift/UVOT upper limits
  14. GRB 060813: pseudo-z from spectral parameters of the prompt
  15. GRB 060814: Swift XRT refined analysis
  16. GRB 060814: VLT optical limits
  17. GRB 060814 - SDSS Pre-Burst Observations
  18. GRB 060814: TAROT optical observations
  19. GRB 060814: Swift detection of a bright burst
  20. Konus-Wind observation of GRB 060813
  21. GRB060813: Swift/UVOT upper limits
  22. GRB 060813: Swift XRT refined analysis
  23. GRB 060813: Refined analysis of the Swift-BAT burst
  24. GRB 060813: Swift detection of a burst
  25. GRB051109B: Late-time Radio Observations
  26. Image of the dust-scattering halo around SGR 1806-20
  27. Second VLA limit on new radio point source in SGR 1806-20
  28. A dust-scattering halo detected around SGR 1806-20
  29. GRB 060805B: pseudo-z from spectral parameters of the prompt emission
  30. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  31. GRB060807: Possible Highly Significant X-ray Emission Lines
  32. GRB060714: optical observations
  33. IBAS Alert n. 3422: not a GRB
  34. GRB 060729: An update on the Swift XRT and UVOT observations
  35. GRB060717: optical observations
  36. GRB060807: Optical limiting magnitudes
  37. GRB 060805B: optical observation at Sierra Nevada
  38. GRB 060805B: XRT Team Analysis
  39. VLA Upper Limit on Outburst of SGR 1806-20
  40. GRB060806 is similar to previous activity of SGR1806-20
  41. GRB 060807: UVOT Upper limits
  42. GRB 060807: afterglow confirmation
  43. GRB 060807: XRT Team refined analysis
  44. GRB 060807: K- and R-band observations
  45. GRB 060807: Refined analysis of the Swift-BAT burst
  46. GRB060807: optical afterglow candidate
  47. GRB060806 = SGR1806-20
  48. GRB 060805B: RHESSI Spectral Fit
  49. GRB060807: optical upper limit in white light
  50. IPN triangulation of GRB060806 (long, exceptionally bright)
  51. GRB060807 - SDSS Pre-burst Observations
  52. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  53. GRB 060805B: Swift/UVOT Upper Limits
  54. GRB 060807, optical observation
  55. GRB 060807: Kanazawa R-band observation
  56. GRB 060807: optical limit
  57. GRB 060807: Swift detection of a burst
  58. GRB 060801: Second Epoch WSRT Radio Observations
  59. IPN triangulation of GRB060805B
  60. GRB060805 Liverpool Telescope observations
  61. GRB 060805: optical upper limit in R
  62. GRB 060805: XRT Team Refined Analysis
  63. GRB 060805: Swift-BAT Refined Analysis
  64. GRB 060805: Swift/UVOT Upper Limits
  65. GRB 060805: P60 Observations
  66. GRB 060805: KAIT observations
  67. GRB 060805 - SDSS Pre-Burst Observations
  68. GRB 060805: Swift detection of a burst
  69. GRB 060804: Swift UVOT observations
  70. GRB 060804: Swift-XRT Team Refined Analysis
  71. GRB 060804: Refined analysis of the Swift-BAT burst
  72. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  73. GRB 060728: Upper limits of the X-ray emission
  74. GRB 060801: no variability of optical sources
  75. IBAS Alert 3418: not a GRB
  76. GRB 060801: WSRT Radio Observations
  77. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  78. GRB060801: Radio Observations
  79. GRB 051109B: Bright spiral host galaxy at low redshift
  80. GRB 060801: optical observations at FORS2/VLT
  81. GRB060801: Swift/UVOT Upper Limits
  82. GRB 060801: optical observations at Hanle and Calar Alto
  83. GRB060801: optical upper limit in R
  84. GRB 060801: Swift XRT refined analysis
  85. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  86. GRB 060801, optical observation
  87. GRB 060801: Kanazawa Optical Observation
  88. GRB 060801: Swift detection of a short burst
  89. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  90. GRB 060218 / SN 2006aj Nebular Spectrum
  91. IBAS Alert n. 3415: not a GRB
  92. Swift-BAT trigger 221873 is not a GRB or a Transient
  93. GRB 060729 redshift
  94. GRB 060719: TORTOREM optical upper limits
  95. GRB 060729: Swift/UVOT Detections
  96. GRB 060729: Refined analysis of the Swift-BAT burst
  97. GRB 060729: Swift-XRT refined analysis
  98. GRB 060729 : Planned XMM-Newton observation
  99. GRB 060729: Swift/UVOT Observations
  100. GRB 060729: ROTSE-III Detection of Optical Counterpart

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