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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 060904B: RTT150 optical observations
  2. GRB060904A: Swift/UVOT optical observations
  3. GRB 060904A: Subaru NIR observation
  4. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  5. GRB 060904B: Swift-BAT refined analysis
  6. GRB060904b: Optical observations with Swift/UVOT
  7. Konus-Wind observation of GRB 060904A
  8. GRB 060904B: Swift-XRT refined analysis
  9. GRB 060904A: Refined analysis of the Swift-BAT burst
  10. GRB 060904A: Swift-XRT refined analysis
  11. GRB 060904A: Suzaku-XIS and -HXD observation plan
  12. GRB 060904B: VLT redshift
  13. GRB 060904A: P60 Observations
  14. GRB 060904B: Optical observations at Crni Vrh
  15. GRB060904B: Watcher observations
  16. GRB 060904B BOOTES-IR and 1.5m OSN observations
  17. GRB 060904B: TAROT optical counterpart observations
  18. GRB060904B - SDSS Pre-Burst Observations
  19. GRB 060904: TAROT optical observations
  20. GRB 060904B: Swift detection of a burst with optical counterpart
  21. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  22. GRB060904 - SDSS Pre-Burst Observations
  23. GRB 060904: Swift detection of a bright burst
  24. GRB060901: Optical observations
  25. 060901: Swift UVOT followup observations
  26. GRB 060901: pseudo-z from spectral parameters of the prompt
  27. Konus-Wind observation of GRB 060901
  28. GRB 060901: SMARTS optical/IR observations update
  29. GRB 060901: Swift/XRT Refined Analysis
  30. GRB 060901: SMARTS optical/IR observations
  31. GRB 060901: Swift/XRT Position
  32. GRB 060901: further INTEGRAL results
  33. GRB 060901: Watcher observations
  34. GRB 060901: a long GRB detected by INTEGRAL
  35. Two bright bursts from SGR 1806-20 detected with IBAS
  36. GRB 060605, observations using an Integral Field Unit
  37. GRB 060604: VLA Observation
  38. GRB 060814: Suzaku/WAM observation of the prompt emission
  39. GRB 060605: VLA Observation
  40. GRB 060707: VLA observation
  41. GRB 060825: VLA observations
  42. GRB 060825: pseudo-z from spectral parameters of the prompt emission
  43. Swift-BAT trigger 226614 is not a GRB
  44. GRB060826 - SDSS Pre-Burst Observations
  45. GRB 060826(?): Swift detection of a possible burst
  46. GRB 060825: XRT Team Refined Analysis
  47. GRB 060825: Swift-BAT Refined Analysis
  48. GRB 060813: Swift/BAT, Konus-Wind, and Suzaku/WAM joint prompt spectral analysis
  49. GRB060825: Liverpool Telescope optical observations
  50. GRB 060825: TNG optical observations
  51. GRB 060825: TAROT optical observations
  52. GRB 060825: P60 Observations
  53. GRB060825: BOOTES-IR optical observations
  54. GRB 060825: Swift detection of a burst
  55. GRB060801: host galaxy redshift
  56. GRB060729: analysis of XMM-Newton observation
  57. GRB 060814: pseudo-z from spectral parameters of the prompt
  58. IBAS Alerts No 3429 and 3430: not GRBs
  59. Radio observations of GRB 060719
  60. GRB 060729, SMARTS optical/IR observations
  61. GRB060814: Break in the XRT light curve
  62. GRB060813: Break in the XRT light curve
  63. GRB 060813: A long, bright GRB detected with Suzaku WAM
  64. GRB 060814: Confirmation of IR afterglow
  65. Konus-Wind observation of GRB 060814
  66. GRB 060814: Refined analysis of the Swift-BAT burst
  67. GRB 060814: P60 Observations
  68. GRB 060814: P200 NIR Observations
  69. GRB 060814: source inside revised XRT error box
  70. GRB 060814: Possible IR counterpart
  71. GRB060805B: optical observations
  72. GRB060814: Swift/UVOT upper limits
  73. GRB 060813: pseudo-z from spectral parameters of the prompt
  74. GRB 060814: Swift XRT refined analysis
  75. GRB 060814: VLT optical limits
  76. GRB 060814 - SDSS Pre-Burst Observations
  77. GRB 060814: TAROT optical observations
  78. GRB 060814: Swift detection of a bright burst
  79. Konus-Wind observation of GRB 060813
  80. GRB060813: Swift/UVOT upper limits
  81. GRB 060813: Swift XRT refined analysis
  82. GRB 060813: Refined analysis of the Swift-BAT burst
  83. GRB 060813: Swift detection of a burst
  84. GRB051109B: Late-time Radio Observations
  85. Image of the dust-scattering halo around SGR 1806-20
  86. Second VLA limit on new radio point source in SGR 1806-20
  87. A dust-scattering halo detected around SGR 1806-20
  88. GRB 060805B: pseudo-z from spectral parameters of the prompt emission
  89. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  90. GRB060807: Possible Highly Significant X-ray Emission Lines
  91. GRB060714: optical observations
  92. IBAS Alert n. 3422: not a GRB
  93. GRB 060729: An update on the Swift XRT and UVOT observations
  94. GRB060717: optical observations
  95. GRB060807: Optical limiting magnitudes
  96. GRB 060805B: optical observation at Sierra Nevada
  97. GRB 060805B: XRT Team Analysis
  98. VLA Upper Limit on Outburst of SGR 1806-20
  99. GRB060806 is similar to previous activity of SGR1806-20
  100. GRB 060807: UVOT Upper limits

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