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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"

26510 results found.

  1. GRB 050915B: Swift/UVOT Upper Limits
  2. GRB 050915a: IR Transient
  3. GRB 050915b, SMARTS optical/IR observations
  4. GRB050915B: Swift-BAT detection of a long bright burst
  5. GRB050915: Swift/UVOT upper limits
  6. GRB 050915: IR Observations
  7. GRB 050915: Swift XRT refined analysis
  8. GRB 050915: Swift-BAT refined analysis
  9. GRB 050915: Swift detection of a GRB
  10. GRB050911: Upper limit on X-ray afterglow
  11. Swift-BAT trigger 155072 ground analysis
  12. Swift-BAT trigger 155072 is probably not a GRB
  13. GRB 050908: DEIMOS spectrum and further analysis
  14. GRB 050911, optical content of Swift/XRT error box
  15. GRB 050911: Swift-BAT refined analysis
  16. GRB 050911: z~0.16 cluster in the field
  17. GRB050911: Swift-BAT detection of a long burst
  18. GRB 050910a: TAROT early optical limits
  19. WIRO observations in I of GRB 050908
  20. GRB 050906: Possible X-ray Counterpart
  21. GRB050908: Swift/UVOT Early upper limits
  22. GRB050908 : Swift-XRT refined analysis
  23. GRB 050908: Swift-BAT refined analysis
  24. GRB 050908: Optical observations
  25. GRB 050908: Optical Observations
  26. GRB 050908: Swift detection of a burst
  27. GRB 050906: Optical observations at the Very Large Telescope
  28. GRB 050904 BAT refined analysis of complete data set
  29. GRB 050904: Subaru Optical Spectroscopy
  30. GRB 050906: MARGE Optical Limits
  31. GRB 050906: Swift-BAT refined analysis
  32. GRB 050906: Swift XRT upper limit
  33. GRB 050906: Radio Observations
  34. GRB 050904: Keck I-band Imaging
  35. GRB050906: P60 Observations
  36. GRB 050904: more VLT NIR observations
  37. GRB 050904: photometric redshift
  38. GRB 050904: Swift/UVOT observations
  39. GRB 050904: NIR object inside the XRT error box
  40. GRB 050904: early Swift XRT analysis results
  41. GRB 050904: SOAR YJ and PROMPT Ic Observations
  42. GRB050904: Optical Observations
  43. GRB050904: P60 Observations
  44. GRB 050904: TAROT optical limits
  45. GRB 050827 : OSN 1.5m optical observations
  46. GRB 050827: P200 NIR Observations
  47. GRB050827: Swift/UVOT upper limits
  48. GRB 050827: Optical Limit
  49. GRB 050827: XRT possible afterglow detection
  50. GRB 050826 : Lulin R band observation
  51. GRB050824: Maidanak optical limits
  52. GRB 050827: Swift-BAT refined analysis
  53. Subaru Observations of GRB050724
  54. GRB 050826: Optical Candidate
  55. GRB 050826: Swift XRT preliminary analysis results
  56. GRB 050826: BAT refined analysis
  57. GRB050826: Swift/UVOT early upper limits
  58. GRB050826: Swift-BAT detection of a long burst
  59. GRB050824: MASTER final analysis of the OT observations
  60. Swift-BAT trigger 152038 is probably not a GRB
  61. GRB 050824: XRT refined analysis and possible afterglow detection
  62. GRB 050824: BAT refined analysis of a soft weak burst
  63. GRB050824: MASTER:OT decay
  64. GRB050824: MASTER observation OT
  65. GRB050805a: MASTER optical candidat
  66. XRF050509c: Radio upper limits from GMRT
  67. GRB050822: Swift/UVOT upper limits
  68. GRB 050820A BAT observations of second, larger episode of emission
  69. GRB050813: Maidanak I-band observations
  70. GRB 050822: Swift-BAT refined analysis
  71. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  72. GRB050820B at FRAM
  73. Swift/UVOT UV Photometry of GRB 050820B
  74. GRB 050822: Swift detection of a long burst
  75. GRB050820a BVRcIc field photometry
  76. GRB050820B XMM-Newton observation
  77. GRB 050820a: NIR Observations by WIRO
  78. GRB 050820B: Swift XRT position
  79. GRB050820B: Refined analysis of the Swift-BAT burst
  80. GRB050820: refined XRT analysis
  81. GRB 050820 Swift-BAT refined analysis
  82. GRB050819: refined XRT analysis
  83. GRB 050820: Swift detection of a GRB
  84. GRB 050819 Swift-BAT refined analysis
  85. GRB050819: Swift-BAT detection of a weak burst
  86. GRB 050817: Optical observations
  87. GRB050817: Negative Optical Observations
  88. GRB 050814: continued fading
  89. GRB050815: Optical afterglow detection by Swift UVOT
  90. GRB050815: XRT refined analysis
  91. GRB050815: Refined analysis of the Swift-BAT burst
  92. GRB 050815: ROTSE-III Optical Limits
  93. GRB050815: Swift-BAT detection of a burst
  94. GRB050814: Fading red source
  95. GRB050814: P60 Optical Afterglow Candidate
  96. GRB 050813: Non-fading of afterglow candidate
  97. GRB 050814: XRT refined analysis
  98. GRB050814: SWIFT/UVOT observation
  99. GRB050814: Refined analysis of the Swift-BAT burst
  100. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C

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