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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"

24887 results found.

  1. GRB 050908: Optical observations
  2. GRB 050908: Optical Observations
  3. GRB 050908: Swift detection of a burst
  4. GRB 050906: Optical observations at the Very Large Telescope
  5. GRB 050904 BAT refined analysis of complete data set
  6. GRB 050904: Subaru Optical Spectroscopy
  7. GRB 050906: MARGE Optical Limits
  8. GRB 050906: Swift-BAT refined analysis
  9. GRB 050906: Swift XRT upper limit
  10. GRB 050906: Radio Observations
  11. GRB 050904: Keck I-band Imaging
  12. GRB050906: P60 Observations
  13. GRB 050904: more VLT NIR observations
  14. GRB 050904: photometric redshift
  15. GRB 050904: Swift/UVOT observations
  16. GRB 050904: NIR object inside the XRT error box
  17. GRB 050904: early Swift XRT analysis results
  18. GRB 050904: SOAR YJ and PROMPT Ic Observations
  19. GRB050904: Optical Observations
  20. GRB050904: P60 Observations
  21. GRB 050904: TAROT optical limits
  22. GRB 050827 : OSN 1.5m optical observations
  23. GRB 050827: P200 NIR Observations
  24. GRB050827: Swift/UVOT upper limits
  25. GRB 050827: Optical Limit
  26. GRB 050827: XRT possible afterglow detection
  27. GRB 050826 : Lulin R band observation
  28. GRB050824: Maidanak optical limits
  29. GRB 050827: Swift-BAT refined analysis
  30. Subaru Observations of GRB050724
  31. GRB 050826: Optical Candidate
  32. GRB 050826: Swift XRT preliminary analysis results
  33. GRB 050826: BAT refined analysis
  34. GRB050826: Swift/UVOT early upper limits
  35. GRB050826: Swift-BAT detection of a long burst
  36. GRB050824: MASTER final analysis of the OT observations
  37. Swift-BAT trigger 152038 is probably not a GRB
  38. GRB 050824: XRT refined analysis and possible afterglow detection
  39. GRB 050824: BAT refined analysis of a soft weak burst
  40. GRB050824: MASTER:OT decay
  41. GRB050824: MASTER observation OT
  42. GRB050805a: MASTER optical candidat
  43. XRF050509c: Radio upper limits from GMRT
  44. GRB050822: Swift/UVOT upper limits
  45. GRB 050820A BAT observations of second, larger episode of emission
  46. GRB050813: Maidanak I-band observations
  47. GRB 050822: Swift-BAT refined analysis
  48. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  49. GRB050820B at FRAM
  50. Swift/UVOT UV Photometry of GRB 050820B
  51. GRB 050822: Swift detection of a long burst
  52. GRB050820a BVRcIc field photometry
  53. GRB050820B XMM-Newton observation
  54. GRB 050820a: NIR Observations by WIRO
  55. GRB 050820B: Swift XRT position
  56. GRB050820B: Refined analysis of the Swift-BAT burst
  57. GRB050820: refined XRT analysis
  58. GRB 050820 Swift-BAT refined analysis
  59. GRB050819: refined XRT analysis
  60. GRB 050820: Swift detection of a GRB
  61. GRB 050819 Swift-BAT refined analysis
  62. GRB050819: Swift-BAT detection of a weak burst
  63. GRB 050817: Optical observations
  64. GRB050817: Negative Optical Observations
  65. GRB 050814: continued fading
  66. GRB050815: Optical afterglow detection by Swift UVOT
  67. GRB050815: XRT refined analysis
  68. GRB050815: Refined analysis of the Swift-BAT burst
  69. GRB 050815: ROTSE-III Optical Limits
  70. GRB050815: Swift-BAT detection of a burst
  71. GRB050814: Fading red source
  72. GRB050814: P60 Optical Afterglow Candidate
  73. GRB 050813: Non-fading of afterglow candidate
  74. GRB 050814: XRT refined analysis
  75. GRB050814: SWIFT/UVOT observation
  76. GRB050814: Refined analysis of the Swift-BAT burst
  77. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  78. GRB 050814: Swift XRT Afterglow Localization
  79. GRB 050814: Swift detection of a burst
  80. GRB 050813: Magellan detection of a high redshift galaxy cluster
  81. GRB050813, SDSS pre-burst observations
  82. GRB 050813: Swift-BAT refined analysis
  83. GRB 050813: Photometry of object in XRT error circle
  84. GRB050813: SWIFT/UVOT observation
  85. GRB 050813: Swift XRT afterglow localization
  86. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  87. Detection of an intermediate burst from SGR 1806-20 on August 8
  88. GRB050805b: CrAO optical limit
  89. GRB050803, optical observations
  90. Retraction of Swift Trigger 149131 (GRB 050805B)
  91. GRB 050805b: OHP optical limits
  92. GRB 050805b: TAROT optical limits
  93. GRB050805b: MASTER optical observations
  94. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  95. GRB050805a: MASTER optical candidat
  96. GRB050802: TNG optical observations
  97. GRB050803: Radio Observation
  98. GRB 050803: RTT150 optical observations
  99. GRB050801: Radio Observation
  100. GRB050730: Radio Detection

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