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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"

28086 results found.

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

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