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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"

22089 results found.

  1. GRB060923C: AROMA optical obsevation
  2. GRB 060923C, optical observation
  3. GRB 060923C: VLT J-band observations
  4. GRB060923B: Swift/UVOT upper limits
  5. GRB 060923A: Keck and Gemini Observations
  6. GRB 060923C: Xinglong TNT optical observations
  7. GRB 060923C: optical observation
  8. GRB 060923C: Swift detection of a burst
  9. GRB 060923B: Swift detection of a burst
  10. GRB 060923: Early Super-LOTIS Observations
  11. GRB 060923: UKIRT nIR observations - candidate afterglow
  12. GRB060923 - SDSS Pre-Burst Observations
  13. GRB 060923: Swift detection of a burst
  14. Swift detection of IGR J17497-2821 (trigger 230504)
  15. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  16. GRB060919: Swift/UVOT optical observations
  17. GRB 060919 : Faulkes South Telescope Observations
  18. GRB 060919: TAROT optical observations
  19. GRB 060919: Swift detection of a burst
  20. GRB 060912A: VLA Observation
  21. GRB 060912A: Probable Host Galaxy
  22. GRB 060912: Correction to GCN 5559
  23. GRB 060912: Swift detection of a burst with an optical afterglow
  24. GRB060906: Danish/DFOSC optical observations
  25. VLA observations of GRB 060908
  26. GRB 060908, Swift-BAT refined analysis
  27. GRB 060908 - SDSS Pre-burst Observations
  28. GRB 060904A : Optical limit
  29. GRB 060908: REM optical prompt observation
  30. GRB 060908: Swift detection of a burst with a bright optical counterpart
  31. GRB060906 , optical observation
  32. GRB 060906: Early RAPTOR optical limits
  33. GRB 060906, Swift-BAT refined spectral analysis
  34. GRB 060906: Swift-UVOT observations
  35. GRB 060906: KAIT observations
  36. GRB 060906: Confirmation of P60 Optical Afterglow
  37. GRB 060906 (?): P60 Optical Afterglow Candidate
  38. GRB 060906: Swift detection of a probable burst
  39. GRB060904b, optical observations
  40. GRB060904A: Swift/UVOT optical observations
  41. GRB 060904A: Subaru NIR observation
  42. GRB060904b: Optical observations with Swift/UVOT
  43. GRB 060904B: Swift-XRT refined analysis
  44. GRB 060904A: Refined analysis of the Swift-BAT burst
  45. GRB 060904A: Suzaku-XIS and -HXD observation plan
  46. GRB 060904A: P60 Observations
  47. GRB 060904B: Optical observations at Crni Vrh
  48. GRB 060904B: TAROT optical counterpart observations
  49. GRB060904B - SDSS Pre-Burst Observations
  50. GRB 060904: TAROT optical observations
  51. GRB 060904B: Swift detection of a burst with optical counterpart
  52. GRB060904 - SDSS Pre-Burst Observations
  53. GRB 060904: Swift detection of a bright burst
  54. GRB060901: Optical observations
  55. 060901: Swift UVOT followup observations
  56. GRB 060901: Swift/XRT Refined Analysis
  57. GRB 060901: Swift/XRT Position
  58. Two bright bursts from SGR 1806-20 detected with IBAS
  59. GRB 060605, observations using an Integral Field Unit
  60. GRB 060604: VLA Observation
  61. GRB 060605: VLA Observation
  62. GRB 060707: VLA observation
  63. GRB 060825: VLA observations
  64. GRB060826 - SDSS Pre-Burst Observations
  65. GRB 060826(?): Swift detection of a possible burst
  66. GRB 060825: TNG optical observations
  67. GRB 060825: TAROT optical observations
  68. GRB 060825: P60 Observations
  69. GRB 060825: Swift detection of a burst
  70. Radio observations of GRB 060719
  71. GRB 060729, SMARTS optical/IR observations
  72. GRB 060814: P60 Observations
  73. GRB 060814: P200 NIR Observations
  74. GRB060814: Swift/UVOT upper limits
  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. GRB060813: Swift/UVOT upper limits
  80. GRB 060813: Swift detection of a burst
  81. GRB051109B: Late-time Radio Observations
  82. A dust-scattering halo detected around SGR 1806-20
  83. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  84. GRB060807: Possible Highly Significant X-ray Emission Lines
  85. GRB 060729: An update on the Swift XRT and UVOT observations
  86. GRB060717: optical observations
  87. GRB 060805B: XRT Team Analysis
  88. GRB060806 is similar to previous activity of SGR1806-20
  89. GRB 060807: UVOT Upper limits
  90. GRB060807: optical afterglow candidate
  91. IPN triangulation of GRB060806 (long, exceptionally bright)
  92. GRB060807 - SDSS Pre-burst Observations
  93. GRB 060805B: Swift/UVOT Upper Limits
  94. GRB 060807, optical observation
  95. GRB 060807: Kanazawa R-band observation
  96. GRB 060807: Swift detection of a burst
  97. IPN triangulation of GRB060805B
  98. GRB060805 Liverpool Telescope observations
  99. GRB 060805: XRT Team Refined Analysis
  100. GRB 060805: Swift/UVOT Upper Limits

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