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

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