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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 060825: TNG optical observations
  2. GRB 060825: TAROT optical observations
  3. GRB 060825: P60 Observations
  4. GRB060825: BOOTES-IR optical observations
  5. GRB 060825: Swift detection of a burst
  6. GRB060801: host galaxy redshift
  7. GRB060729: analysis of XMM-Newton observation
  8. GRB 060814: pseudo-z from spectral parameters of the prompt
  9. IBAS Alerts No 3429 and 3430: not GRBs
  10. Radio observations of GRB 060719
  11. GRB 060729, SMARTS optical/IR observations
  12. GRB060814: Break in the XRT light curve
  13. GRB060813: Break in the XRT light curve
  14. GRB 060813: A long, bright GRB detected with Suzaku WAM
  15. GRB 060814: Confirmation of IR afterglow
  16. Konus-Wind observation of GRB 060814
  17. GRB 060814: Refined analysis of the Swift-BAT burst
  18. GRB 060814: P60 Observations
  19. GRB 060814: P200 NIR Observations
  20. GRB 060814: source inside revised XRT error box
  21. GRB 060814: Possible IR counterpart
  22. GRB060805B: optical observations
  23. GRB060814: Swift/UVOT upper limits
  24. GRB 060813: pseudo-z from spectral parameters of the prompt
  25. GRB 060814: Swift XRT refined analysis
  26. GRB 060814: VLT optical limits
  27. GRB 060814 - SDSS Pre-Burst Observations
  28. GRB 060814: TAROT optical observations
  29. GRB 060814: Swift detection of a bright burst
  30. Konus-Wind observation of GRB 060813
  31. GRB060813: Swift/UVOT upper limits
  32. GRB 060813: Swift XRT refined analysis
  33. GRB 060813: Refined analysis of the Swift-BAT burst
  34. GRB 060813: Swift detection of a burst
  35. GRB051109B: Late-time Radio Observations
  36. Image of the dust-scattering halo around SGR 1806-20
  37. Second VLA limit on new radio point source in SGR 1806-20
  38. A dust-scattering halo detected around SGR 1806-20
  39. GRB 060805B: pseudo-z from spectral parameters of the prompt emission
  40. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  41. GRB060807: Possible Highly Significant X-ray Emission Lines
  42. GRB060714: optical observations
  43. IBAS Alert n. 3422: not a GRB
  44. GRB 060729: An update on the Swift XRT and UVOT observations
  45. GRB060717: optical observations
  46. GRB060807: Optical limiting magnitudes
  47. GRB 060805B: optical observation at Sierra Nevada
  48. GRB 060805B: XRT Team Analysis
  49. VLA Upper Limit on Outburst of SGR 1806-20
  50. GRB060806 is similar to previous activity of SGR1806-20
  51. GRB 060807: UVOT Upper limits
  52. GRB 060807: afterglow confirmation
  53. GRB 060807: XRT Team refined analysis
  54. GRB 060807: K- and R-band observations
  55. GRB 060807: Refined analysis of the Swift-BAT burst
  56. GRB060807: optical afterglow candidate
  57. GRB060806 = SGR1806-20
  58. GRB 060805B: RHESSI Spectral Fit
  59. GRB060807: optical upper limit in white light
  60. IPN triangulation of GRB060806 (long, exceptionally bright)
  61. GRB060807 - SDSS Pre-burst Observations
  62. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  63. GRB 060805B: Swift/UVOT Upper Limits
  64. GRB 060807, optical observation
  65. GRB 060807: Kanazawa R-band observation
  66. GRB 060807: optical limit
  67. GRB 060807: Swift detection of a burst
  68. GRB 060801: Second Epoch WSRT Radio Observations
  69. IPN triangulation of GRB060805B
  70. GRB060805 Liverpool Telescope observations
  71. GRB 060805: optical upper limit in R
  72. GRB 060805: XRT Team Refined Analysis
  73. GRB 060805: Swift-BAT Refined Analysis
  74. GRB 060805: Swift/UVOT Upper Limits
  75. GRB 060805: P60 Observations
  76. GRB 060805: KAIT observations
  77. GRB 060805 - SDSS Pre-Burst Observations
  78. GRB 060805: Swift detection of a burst
  79. GRB 060804: Swift UVOT observations
  80. GRB 060804: Swift-XRT Team Refined Analysis
  81. GRB 060804: Refined analysis of the Swift-BAT burst
  82. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  83. GRB 060728: Upper limits of the X-ray emission
  84. GRB 060801: no variability of optical sources
  85. IBAS Alert 3418: not a GRB
  86. GRB 060801: WSRT Radio Observations
  87. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  88. GRB060801: Radio Observations
  89. GRB 051109B: Bright spiral host galaxy at low redshift
  90. GRB 060801: optical observations at FORS2/VLT
  91. GRB060801: Swift/UVOT Upper Limits
  92. GRB 060801: optical observations at Hanle and Calar Alto
  93. GRB060801: optical upper limit in R
  94. GRB 060801: Swift XRT refined analysis
  95. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  96. GRB 060801, optical observation
  97. GRB 060801: Kanazawa Optical Observation
  98. GRB 060801: Swift detection of a short burst
  99. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  100. GRB 060218 / SN 2006aj Nebular Spectrum

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