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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"

28088 results found.

  1. GRB 050908: Swift-BAT refined analysis
  2. GRB 050908: Optical observations
  3. GRB 050908: Optical Observations
  4. GRB 050908: Swift detection of a burst
  5. GRB 050906: Optical observations at the Very Large Telescope
  6. GRB 050904 BAT refined analysis of complete data set
  7. GRB 050904: Subaru Optical Spectroscopy
  8. GRB 050906: MARGE Optical Limits
  9. GRB 050906: Swift-BAT refined analysis
  10. GRB 050906: Swift XRT upper limit
  11. GRB 050906: Radio Observations
  12. GRB 050904: Keck I-band Imaging
  13. GRB050906: P60 Observations
  14. GRB 050904: more VLT NIR observations
  15. GRB 050904: photometric redshift
  16. GRB 050904: Swift/UVOT observations
  17. GRB 050904: NIR object inside the XRT error box
  18. GRB 050904: early Swift XRT analysis results
  19. GRB 050904: SOAR YJ and PROMPT Ic Observations
  20. GRB050904: Optical Observations
  21. GRB050904: P60 Observations
  22. GRB 050904: TAROT optical limits
  23. GRB 050827 : OSN 1.5m optical observations
  24. GRB 050827: P200 NIR Observations
  25. GRB050827: Swift/UVOT upper limits
  26. GRB 050827: Optical Limit
  27. GRB 050827: XRT possible afterglow detection
  28. GRB 050826 : Lulin R band observation
  29. GRB050824: Maidanak optical limits
  30. GRB 050827: Swift-BAT refined analysis
  31. Subaru Observations of GRB050724
  32. GRB 050826: Optical Candidate
  33. GRB 050826: Swift XRT preliminary analysis results
  34. GRB 050826: BAT refined analysis
  35. GRB050826: Swift/UVOT early upper limits
  36. GRB050826: Swift-BAT detection of a long burst
  37. GRB050824: MASTER final analysis of the OT observations
  38. Swift-BAT trigger 152038 is probably not a GRB
  39. GRB 050824: XRT refined analysis and possible afterglow detection
  40. GRB 050824: BAT refined analysis of a soft weak burst
  41. GRB050824: MASTER:OT decay
  42. GRB050824: MASTER observation OT
  43. GRB050805a: MASTER optical candidat
  44. XRF050509c: Radio upper limits from GMRT
  45. GRB050822: Swift/UVOT upper limits
  46. GRB 050820A BAT observations of second, larger episode of emission
  47. GRB050813: Maidanak I-band observations
  48. GRB 050822: Swift-BAT refined analysis
  49. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  50. GRB050820B at FRAM
  51. Swift/UVOT UV Photometry of GRB 050820B
  52. GRB 050822: Swift detection of a long burst
  53. GRB050820a BVRcIc field photometry
  54. GRB050820B XMM-Newton observation
  55. GRB 050820a: NIR Observations by WIRO
  56. GRB 050820B: Swift XRT position
  57. GRB050820B: Refined analysis of the Swift-BAT burst
  58. GRB050820: refined XRT analysis
  59. GRB 050820 Swift-BAT refined analysis
  60. GRB050819: refined XRT analysis
  61. GRB 050820: Swift detection of a GRB
  62. GRB 050819 Swift-BAT refined analysis
  63. GRB050819: Swift-BAT detection of a weak burst
  64. GRB 050817: Optical observations
  65. GRB050817: Negative Optical Observations
  66. GRB 050814: continued fading
  67. GRB050815: Optical afterglow detection by Swift UVOT
  68. GRB050815: XRT refined analysis
  69. GRB050815: Refined analysis of the Swift-BAT burst
  70. GRB 050815: ROTSE-III Optical Limits
  71. GRB050815: Swift-BAT detection of a burst
  72. GRB050814: Fading red source
  73. GRB050814: P60 Optical Afterglow Candidate
  74. GRB 050813: Non-fading of afterglow candidate
  75. GRB 050814: XRT refined analysis
  76. GRB050814: SWIFT/UVOT observation
  77. GRB050814: Refined analysis of the Swift-BAT burst
  78. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  79. GRB 050814: Swift XRT Afterglow Localization
  80. GRB 050814: Swift detection of a burst
  81. GRB 050813: Magellan detection of a high redshift galaxy cluster
  82. GRB050813, SDSS pre-burst observations
  83. GRB 050813: Swift-BAT refined analysis
  84. GRB 050813: Photometry of object in XRT error circle
  85. GRB050813: SWIFT/UVOT observation
  86. GRB 050813: Swift XRT afterglow localization
  87. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  88. Detection of an intermediate burst from SGR 1806-20 on August 8
  89. GRB050805b: CrAO optical limit
  90. GRB050803, optical observations
  91. Retraction of Swift Trigger 149131 (GRB 050805B)
  92. GRB 050805b: OHP optical limits
  93. GRB 050805b: TAROT optical limits
  94. GRB050805b: MASTER optical observations
  95. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  96. GRB050805a: MASTER optical candidat
  97. GRB050802: TNG optical observations
  98. GRB050803: Radio Observation
  99. GRB 050803: RTT150 optical observations
  100. GRB050801: Radio Observation

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