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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"

28091 results found.

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

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