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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"

28083 results found.

  1. GRB 050904 BAT refined analysis of complete data set
  2. GRB 050904: Subaru Optical Spectroscopy
  3. GRB 050906: MARGE Optical Limits
  4. GRB 050906: Swift-BAT refined analysis
  5. GRB 050906: Swift XRT upper limit
  6. GRB 050906: Radio Observations
  7. GRB 050904: Keck I-band Imaging
  8. GRB050906: P60 Observations
  9. GRB 050904: more VLT NIR observations
  10. GRB 050904: photometric redshift
  11. GRB 050904: Swift/UVOT observations
  12. GRB 050904: NIR object inside the XRT error box
  13. GRB 050904: early Swift XRT analysis results
  14. GRB 050904: SOAR YJ and PROMPT Ic Observations
  15. GRB050904: Optical Observations
  16. GRB050904: P60 Observations
  17. GRB 050904: TAROT optical limits
  18. GRB 050827 : OSN 1.5m optical observations
  19. GRB 050827: P200 NIR Observations
  20. GRB050827: Swift/UVOT upper limits
  21. GRB 050827: Optical Limit
  22. GRB 050827: XRT possible afterglow detection
  23. GRB 050826 : Lulin R band observation
  24. GRB050824: Maidanak optical limits
  25. GRB 050827: Swift-BAT refined analysis
  26. Subaru Observations of GRB050724
  27. GRB 050826: Optical Candidate
  28. GRB 050826: Swift XRT preliminary analysis results
  29. GRB 050826: BAT refined analysis
  30. GRB050826: Swift/UVOT early upper limits
  31. GRB050826: Swift-BAT detection of a long burst
  32. GRB050824: MASTER final analysis of the OT observations
  33. Swift-BAT trigger 152038 is probably not a GRB
  34. GRB 050824: XRT refined analysis and possible afterglow detection
  35. GRB 050824: BAT refined analysis of a soft weak burst
  36. GRB050824: MASTER:OT decay
  37. GRB050824: MASTER observation OT
  38. GRB050805a: MASTER optical candidat
  39. XRF050509c: Radio upper limits from GMRT
  40. GRB050822: Swift/UVOT upper limits
  41. GRB 050820A BAT observations of second, larger episode of emission
  42. GRB050813: Maidanak I-band observations
  43. GRB 050822: Swift-BAT refined analysis
  44. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  45. GRB050820B at FRAM
  46. Swift/UVOT UV Photometry of GRB 050820B
  47. GRB 050822: Swift detection of a long burst
  48. GRB050820a BVRcIc field photometry
  49. GRB050820B XMM-Newton observation
  50. GRB 050820a: NIR Observations by WIRO
  51. GRB 050820B: Swift XRT position
  52. GRB050820B: Refined analysis of the Swift-BAT burst
  53. GRB050820: refined XRT analysis
  54. GRB 050820 Swift-BAT refined analysis
  55. GRB050819: refined XRT analysis
  56. GRB 050820: Swift detection of a GRB
  57. GRB 050819 Swift-BAT refined analysis
  58. GRB050819: Swift-BAT detection of a weak burst
  59. GRB 050817: Optical observations
  60. GRB050817: Negative Optical Observations
  61. GRB 050814: continued fading
  62. GRB050815: Optical afterglow detection by Swift UVOT
  63. GRB050815: XRT refined analysis
  64. GRB050815: Refined analysis of the Swift-BAT burst
  65. GRB 050815: ROTSE-III Optical Limits
  66. GRB050815: Swift-BAT detection of a burst
  67. GRB050814: Fading red source
  68. GRB050814: P60 Optical Afterglow Candidate
  69. GRB 050813: Non-fading of afterglow candidate
  70. GRB 050814: XRT refined analysis
  71. GRB050814: SWIFT/UVOT observation
  72. GRB050814: Refined analysis of the Swift-BAT burst
  73. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  74. GRB 050814: Swift XRT Afterglow Localization
  75. GRB 050814: Swift detection of a burst
  76. GRB 050813: Magellan detection of a high redshift galaxy cluster
  77. GRB050813, SDSS pre-burst observations
  78. GRB 050813: Swift-BAT refined analysis
  79. GRB 050813: Photometry of object in XRT error circle
  80. GRB050813: SWIFT/UVOT observation
  81. GRB 050813: Swift XRT afterglow localization
  82. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  83. Detection of an intermediate burst from SGR 1806-20 on August 8
  84. GRB050805b: CrAO optical limit
  85. GRB050803, optical observations
  86. Retraction of Swift Trigger 149131 (GRB 050805B)
  87. GRB 050805b: OHP optical limits
  88. GRB 050805b: TAROT optical limits
  89. GRB050805b: MASTER optical observations
  90. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  91. GRB050805a: MASTER optical candidat
  92. GRB050802: TNG optical observations
  93. GRB050803: Radio Observation
  94. GRB 050803: RTT150 optical observations
  95. GRB050801: Radio Observation
  96. GRB050730: Radio Detection
  97. GRB 050803: Keck Observations
  98. GRB 050803: Swift-BAT refined analysis
  99. GRB 050802.422: Fading of the afterglow and detection of the host
  100. GRB 050803: early Swift XRT analysis results

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