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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"

28089 results found.

  1. GRB050908 : Swift-XRT refined analysis
  2. GRB 050908: Swift-BAT refined analysis
  3. GRB 050908: Optical observations
  4. GRB 050908: Optical Observations
  5. GRB 050908: Swift detection of a burst
  6. GRB 050906: Optical observations at the Very Large Telescope
  7. GRB 050904 BAT refined analysis of complete data set
  8. GRB 050904: Subaru Optical Spectroscopy
  9. GRB 050906: MARGE Optical Limits
  10. GRB 050906: Swift-BAT refined analysis
  11. GRB 050906: Swift XRT upper limit
  12. GRB 050906: Radio Observations
  13. GRB 050904: Keck I-band Imaging
  14. GRB050906: P60 Observations
  15. GRB 050904: more VLT NIR observations
  16. GRB 050904: photometric redshift
  17. GRB 050904: Swift/UVOT observations
  18. GRB 050904: NIR object inside the XRT error box
  19. GRB 050904: early Swift XRT analysis results
  20. GRB 050904: SOAR YJ and PROMPT Ic Observations
  21. GRB050904: Optical Observations
  22. GRB050904: P60 Observations
  23. GRB 050904: TAROT optical limits
  24. GRB 050827 : OSN 1.5m optical observations
  25. GRB 050827: P200 NIR Observations
  26. GRB050827: Swift/UVOT upper limits
  27. GRB 050827: Optical Limit
  28. GRB 050827: XRT possible afterglow detection
  29. GRB 050826 : Lulin R band observation
  30. GRB050824: Maidanak optical limits
  31. GRB 050827: Swift-BAT refined analysis
  32. Subaru Observations of GRB050724
  33. GRB 050826: Optical Candidate
  34. GRB 050826: Swift XRT preliminary analysis results
  35. GRB 050826: BAT refined analysis
  36. GRB050826: Swift/UVOT early upper limits
  37. GRB050826: Swift-BAT detection of a long burst
  38. GRB050824: MASTER final analysis of the OT observations
  39. Swift-BAT trigger 152038 is probably not a GRB
  40. GRB 050824: XRT refined analysis and possible afterglow detection
  41. GRB 050824: BAT refined analysis of a soft weak burst
  42. GRB050824: MASTER:OT decay
  43. GRB050824: MASTER observation OT
  44. GRB050805a: MASTER optical candidat
  45. XRF050509c: Radio upper limits from GMRT
  46. GRB050822: Swift/UVOT upper limits
  47. GRB 050820A BAT observations of second, larger episode of emission
  48. GRB050813: Maidanak I-band observations
  49. GRB 050822: Swift-BAT refined analysis
  50. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  51. GRB050820B at FRAM
  52. Swift/UVOT UV Photometry of GRB 050820B
  53. GRB 050822: Swift detection of a long burst
  54. GRB050820a BVRcIc field photometry
  55. GRB050820B XMM-Newton observation
  56. GRB 050820a: NIR Observations by WIRO
  57. GRB 050820B: Swift XRT position
  58. GRB050820B: Refined analysis of the Swift-BAT burst
  59. GRB050820: refined XRT analysis
  60. GRB 050820 Swift-BAT refined analysis
  61. GRB050819: refined XRT analysis
  62. GRB 050820: Swift detection of a GRB
  63. GRB 050819 Swift-BAT refined analysis
  64. GRB050819: Swift-BAT detection of a weak burst
  65. GRB 050817: Optical observations
  66. GRB050817: Negative Optical Observations
  67. GRB 050814: continued fading
  68. GRB050815: Optical afterglow detection by Swift UVOT
  69. GRB050815: XRT refined analysis
  70. GRB050815: Refined analysis of the Swift-BAT burst
  71. GRB 050815: ROTSE-III Optical Limits
  72. GRB050815: Swift-BAT detection of a burst
  73. GRB050814: Fading red source
  74. GRB050814: P60 Optical Afterglow Candidate
  75. GRB 050813: Non-fading of afterglow candidate
  76. GRB 050814: XRT refined analysis
  77. GRB050814: SWIFT/UVOT observation
  78. GRB050814: Refined analysis of the Swift-BAT burst
  79. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  80. GRB 050814: Swift XRT Afterglow Localization
  81. GRB 050814: Swift detection of a burst
  82. GRB 050813: Magellan detection of a high redshift galaxy cluster
  83. GRB050813, SDSS pre-burst observations
  84. GRB 050813: Swift-BAT refined analysis
  85. GRB 050813: Photometry of object in XRT error circle
  86. GRB050813: SWIFT/UVOT observation
  87. GRB 050813: Swift XRT afterglow localization
  88. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  89. Detection of an intermediate burst from SGR 1806-20 on August 8
  90. GRB050805b: CrAO optical limit
  91. GRB050803, optical observations
  92. Retraction of Swift Trigger 149131 (GRB 050805B)
  93. GRB 050805b: OHP optical limits
  94. GRB 050805b: TAROT optical limits
  95. GRB050805b: MASTER optical observations
  96. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  97. GRB050805a: MASTER optical candidat
  98. GRB050802: TNG optical observations
  99. GRB050803: Radio Observation
  100. GRB 050803: RTT150 optical observations

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