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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 060912: Xinglong TNT optical observations
  2. GRB 060912: Swift detection of a burst with an optical afterglow
  3. GRB060906: Danish/DFOSC optical observations
  4. VLA observations of GRB 060908
  5. GRB 060908: redshift
  6. GRB 060908, Swift/XRT refined analysis
  7. GRB 060908: Swift/UVOT Observations
  8. GRB 060908: Danish/DFOSC optical observations
  9. GRB 060908, Swift-BAT refined analysis
  10. GRB 060908 - SDSS Pre-burst Observations
  11. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  12. GRB 060904B: Kiso Optical observation
  13. GRB 060904A : Optical limit
  14. GRB 060908: REM optical prompt observation
  15. GRB 060908: PROMPT Detection of a Bright Counterpart
  16. GRB 060908: Swift detection of a burst with a bright optical counterpart
  17. GRB 060904A: Suzaku/WAM observation of the prompt emission
  18. GRB060906 , optical observation
  19. GRB060904b optical detections (delayed report due to internet outage)
  20. GRB 060906: optical observation
  21. GRB 060906: Early RAPTOR optical limits
  22. GRB 060906, Swift-BAT refined spectral analysis
  23. GRB 060906: Swift/XRT Refined Analysis
  24. GRB 060906: Swift-UVOT observations
  25. VLT redshift of GRB 060906
  26. GRB 060906, Swift-BAT refined analysis
  27. GRB 060906: FRAM observations - flash determination (airplane)
  28. GRB 060906: KAIT observations
  29. GRB 060906: Confirmation of P60 Optical Afterglow
  30. GRB 060906: observations with FRAM
  31. GRB 060906 (?): P60 Optical Afterglow Candidate
  32. GRB 060906: Swift detection of a probable burst
  33. GRB 060904A Milagro GeV/TeV Observations
  34. GRB060904b, optical observations
  35. GRB 060904b: SMARTS optical/IR afterglow observations
  36. GRB 060904B: RTT150 optical observations
  37. GRB060904A: Swift/UVOT optical observations
  38. GRB 060904A: Subaru NIR observation
  39. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  40. GRB 060904B: Swift-BAT refined analysis
  41. GRB060904b: Optical observations with Swift/UVOT
  42. Konus-Wind observation of GRB 060904A
  43. GRB 060904B: Swift-XRT refined analysis
  44. GRB 060904A: Refined analysis of the Swift-BAT burst
  45. GRB 060904A: Swift-XRT refined analysis
  46. GRB 060904A: Suzaku-XIS and -HXD observation plan
  47. GRB 060904B: VLT redshift
  48. GRB 060904A: P60 Observations
  49. GRB 060904B: Optical observations at Crni Vrh
  50. GRB060904B: Watcher observations
  51. GRB 060904B BOOTES-IR and 1.5m OSN observations
  52. GRB 060904B: TAROT optical counterpart observations
  53. GRB060904B - SDSS Pre-Burst Observations
  54. GRB 060904: TAROT optical observations
  55. GRB 060904B: Swift detection of a burst with optical counterpart
  56. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  57. GRB060904 - SDSS Pre-Burst Observations
  58. GRB 060904: Swift detection of a bright burst
  59. GRB060901: Optical observations
  60. 060901: Swift UVOT followup observations
  61. GRB 060901: pseudo-z from spectral parameters of the prompt
  62. Konus-Wind observation of GRB 060901
  63. GRB 060901: SMARTS optical/IR observations update
  64. GRB 060901: Swift/XRT Refined Analysis
  65. GRB 060901: SMARTS optical/IR observations
  66. GRB 060901: Swift/XRT Position
  67. GRB 060901: further INTEGRAL results
  68. GRB 060901: Watcher observations
  69. GRB 060901: a long GRB detected by INTEGRAL
  70. Two bright bursts from SGR 1806-20 detected with IBAS
  71. GRB 060605, observations using an Integral Field Unit
  72. GRB 060604: VLA Observation
  73. GRB 060814: Suzaku/WAM observation of the prompt emission
  74. GRB 060605: VLA Observation
  75. GRB 060707: VLA observation
  76. GRB 060825: VLA observations
  77. GRB 060825: pseudo-z from spectral parameters of the prompt emission
  78. Swift-BAT trigger 226614 is not a GRB
  79. GRB060826 - SDSS Pre-Burst Observations
  80. GRB 060826(?): Swift detection of a possible burst
  81. GRB 060825: XRT Team Refined Analysis
  82. GRB 060825: Swift-BAT Refined Analysis
  83. GRB 060813: Swift/BAT, Konus-Wind, and Suzaku/WAM joint prompt spectral analysis
  84. GRB060825: Liverpool Telescope optical observations
  85. GRB 060825: TNG optical observations
  86. GRB 060825: TAROT optical observations
  87. GRB 060825: P60 Observations
  88. GRB060825: BOOTES-IR optical observations
  89. GRB 060825: Swift detection of a burst
  90. GRB060801: host galaxy redshift
  91. GRB060729: analysis of XMM-Newton observation
  92. GRB 060814: pseudo-z from spectral parameters of the prompt
  93. IBAS Alerts No 3429 and 3430: not GRBs
  94. Radio observations of GRB 060719
  95. GRB 060729, SMARTS optical/IR observations
  96. GRB060814: Break in the XRT light curve
  97. GRB060813: Break in the XRT light curve
  98. GRB 060813: A long, bright GRB detected with Suzaku WAM
  99. GRB 060814: Confirmation of IR afterglow
  100. Konus-Wind observation of GRB 060814

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