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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 060908: Danish/DFOSC optical observations
  2. GRB 060908, Swift-BAT refined analysis
  3. GRB 060908 - SDSS Pre-burst Observations
  4. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  5. GRB 060904B: Kiso Optical observation
  6. GRB 060904A : Optical limit
  7. GRB 060908: REM optical prompt observation
  8. GRB 060908: PROMPT Detection of a Bright Counterpart
  9. GRB 060908: Swift detection of a burst with a bright optical counterpart
  10. GRB 060904A: Suzaku/WAM observation of the prompt emission
  11. GRB060906 , optical observation
  12. GRB060904b optical detections (delayed report due to internet outage)
  13. GRB 060906: optical observation
  14. GRB 060906: Early RAPTOR optical limits
  15. GRB 060906, Swift-BAT refined spectral analysis
  16. GRB 060906: Swift/XRT Refined Analysis
  17. GRB 060906: Swift-UVOT observations
  18. VLT redshift of GRB 060906
  19. GRB 060906, Swift-BAT refined analysis
  20. GRB 060906: FRAM observations - flash determination (airplane)
  21. GRB 060906: KAIT observations
  22. GRB 060906: Confirmation of P60 Optical Afterglow
  23. GRB 060906: observations with FRAM
  24. GRB 060906 (?): P60 Optical Afterglow Candidate
  25. GRB 060906: Swift detection of a probable burst
  26. GRB 060904A Milagro GeV/TeV Observations
  27. GRB060904b, optical observations
  28. GRB 060904b: SMARTS optical/IR afterglow observations
  29. GRB 060904B: RTT150 optical observations
  30. GRB060904A: Swift/UVOT optical observations
  31. GRB 060904A: Subaru NIR observation
  32. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  33. GRB 060904B: Swift-BAT refined analysis
  34. GRB060904b: Optical observations with Swift/UVOT
  35. Konus-Wind observation of GRB 060904A
  36. GRB 060904B: Swift-XRT refined analysis
  37. GRB 060904A: Refined analysis of the Swift-BAT burst
  38. GRB 060904A: Swift-XRT refined analysis
  39. GRB 060904A: Suzaku-XIS and -HXD observation plan
  40. GRB 060904B: VLT redshift
  41. GRB 060904A: P60 Observations
  42. GRB 060904B: Optical observations at Crni Vrh
  43. GRB060904B: Watcher observations
  44. GRB 060904B BOOTES-IR and 1.5m OSN observations
  45. GRB 060904B: TAROT optical counterpart observations
  46. GRB060904B - SDSS Pre-Burst Observations
  47. GRB 060904: TAROT optical observations
  48. GRB 060904B: Swift detection of a burst with optical counterpart
  49. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  50. GRB060904 - SDSS Pre-Burst Observations
  51. GRB 060904: Swift detection of a bright burst
  52. GRB060901: Optical observations
  53. 060901: Swift UVOT followup observations
  54. GRB 060901: pseudo-z from spectral parameters of the prompt
  55. Konus-Wind observation of GRB 060901
  56. GRB 060901: SMARTS optical/IR observations update
  57. GRB 060901: Swift/XRT Refined Analysis
  58. GRB 060901: SMARTS optical/IR observations
  59. GRB 060901: Swift/XRT Position
  60. GRB 060901: further INTEGRAL results
  61. GRB 060901: Watcher observations
  62. GRB 060901: a long GRB detected by INTEGRAL
  63. Two bright bursts from SGR 1806-20 detected with IBAS
  64. GRB 060605, observations using an Integral Field Unit
  65. GRB 060604: VLA Observation
  66. GRB 060814: Suzaku/WAM observation of the prompt emission
  67. GRB 060605: VLA Observation
  68. GRB 060707: VLA observation
  69. GRB 060825: VLA observations
  70. GRB 060825: pseudo-z from spectral parameters of the prompt emission
  71. Swift-BAT trigger 226614 is not a GRB
  72. GRB060826 - SDSS Pre-Burst Observations
  73. GRB 060826(?): Swift detection of a possible burst
  74. GRB 060825: XRT Team Refined Analysis
  75. GRB 060825: Swift-BAT Refined Analysis
  76. GRB 060813: Swift/BAT, Konus-Wind, and Suzaku/WAM joint prompt spectral analysis
  77. GRB060825: Liverpool Telescope optical observations
  78. GRB 060825: TNG optical observations
  79. GRB 060825: TAROT optical observations
  80. GRB 060825: P60 Observations
  81. GRB060825: BOOTES-IR optical observations
  82. GRB 060825: Swift detection of a burst
  83. GRB060801: host galaxy redshift
  84. GRB060729: analysis of XMM-Newton observation
  85. GRB 060814: pseudo-z from spectral parameters of the prompt
  86. IBAS Alerts No 3429 and 3430: not GRBs
  87. Radio observations of GRB 060719
  88. GRB 060729, SMARTS optical/IR observations
  89. GRB060814: Break in the XRT light curve
  90. GRB060813: Break in the XRT light curve
  91. GRB 060813: A long, bright GRB detected with Suzaku WAM
  92. GRB 060814: Confirmation of IR afterglow
  93. Konus-Wind observation of GRB 060814
  94. GRB 060814: Refined analysis of the Swift-BAT burst
  95. GRB 060814: P60 Observations
  96. GRB 060814: P200 NIR Observations
  97. GRB 060814: source inside revised XRT error box
  98. GRB 060814: Possible IR counterpart
  99. GRB060805B: optical observations
  100. GRB060814: Swift/UVOT upper limits

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