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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"

25998 results found.

  1. GRB 050908: DEIMOS spectrum and further analysis
  2. GRB 050911, optical content of Swift/XRT error box
  3. GRB 050911: Swift-BAT refined analysis
  4. GRB 050911: z~0.16 cluster in the field
  5. GRB050911: Swift-BAT detection of a long burst
  6. GRB 050910a: TAROT early optical limits
  7. WIRO observations in I of GRB 050908
  8. GRB 050906: Possible X-ray Counterpart
  9. GRB050908: Swift/UVOT Early upper limits
  10. GRB050908 : Swift-XRT refined analysis
  11. GRB 050908: Swift-BAT refined analysis
  12. GRB 050908: Optical observations
  13. GRB 050908: Optical Observations
  14. GRB 050908: Swift detection of a burst
  15. GRB 050906: Optical observations at the Very Large Telescope
  16. GRB 050904 BAT refined analysis of complete data set
  17. GRB 050904: Subaru Optical Spectroscopy
  18. GRB 050906: MARGE Optical Limits
  19. GRB 050906: Swift-BAT refined analysis
  20. GRB 050906: Swift XRT upper limit
  21. GRB 050906: Radio Observations
  22. GRB 050904: Keck I-band Imaging
  23. GRB050906: P60 Observations
  24. GRB 050904: more VLT NIR observations
  25. GRB 050904: photometric redshift
  26. GRB 050904: Swift/UVOT observations
  27. GRB 050904: NIR object inside the XRT error box
  28. GRB 050904: early Swift XRT analysis results
  29. GRB 050904: SOAR YJ and PROMPT Ic Observations
  30. GRB050904: Optical Observations
  31. GRB050904: P60 Observations
  32. GRB 050904: TAROT optical limits
  33. GRB 050827 : OSN 1.5m optical observations
  34. GRB 050827: P200 NIR Observations
  35. GRB050827: Swift/UVOT upper limits
  36. GRB 050827: Optical Limit
  37. GRB 050827: XRT possible afterglow detection
  38. GRB 050826 : Lulin R band observation
  39. GRB050824: Maidanak optical limits
  40. GRB 050827: Swift-BAT refined analysis
  41. Subaru Observations of GRB050724
  42. GRB 050826: Optical Candidate
  43. GRB 050826: Swift XRT preliminary analysis results
  44. GRB 050826: BAT refined analysis
  45. GRB050826: Swift/UVOT early upper limits
  46. GRB050826: Swift-BAT detection of a long burst
  47. GRB050824: MASTER final analysis of the OT observations
  48. Swift-BAT trigger 152038 is probably not a GRB
  49. GRB 050824: XRT refined analysis and possible afterglow detection
  50. GRB 050824: BAT refined analysis of a soft weak burst
  51. GRB050824: MASTER:OT decay
  52. GRB050824: MASTER observation OT
  53. GRB050805a: MASTER optical candidat
  54. XRF050509c: Radio upper limits from GMRT
  55. GRB050822: Swift/UVOT upper limits
  56. GRB 050820A BAT observations of second, larger episode of emission
  57. GRB050813: Maidanak I-band observations
  58. GRB 050822: Swift-BAT refined analysis
  59. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  60. GRB050820B at FRAM
  61. Swift/UVOT UV Photometry of GRB 050820B
  62. GRB 050822: Swift detection of a long burst
  63. GRB050820a BVRcIc field photometry
  64. GRB050820B XMM-Newton observation
  65. GRB 050820a: NIR Observations by WIRO
  66. GRB 050820B: Swift XRT position
  67. GRB050820B: Refined analysis of the Swift-BAT burst
  68. GRB050820: refined XRT analysis
  69. GRB 050820 Swift-BAT refined analysis
  70. GRB050819: refined XRT analysis
  71. GRB 050820: Swift detection of a GRB
  72. GRB 050819 Swift-BAT refined analysis
  73. GRB050819: Swift-BAT detection of a weak burst
  74. GRB 050817: Optical observations
  75. GRB050817: Negative Optical Observations
  76. GRB 050814: continued fading
  77. GRB050815: Optical afterglow detection by Swift UVOT
  78. GRB050815: XRT refined analysis
  79. GRB050815: Refined analysis of the Swift-BAT burst
  80. GRB 050815: ROTSE-III Optical Limits
  81. GRB050815: Swift-BAT detection of a burst
  82. GRB050814: Fading red source
  83. GRB050814: P60 Optical Afterglow Candidate
  84. GRB 050813: Non-fading of afterglow candidate
  85. GRB 050814: XRT refined analysis
  86. GRB050814: SWIFT/UVOT observation
  87. GRB050814: Refined analysis of the Swift-BAT burst
  88. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  89. GRB 050814: Swift XRT Afterglow Localization
  90. GRB 050814: Swift detection of a burst
  91. GRB 050813: Magellan detection of a high redshift galaxy cluster
  92. GRB050813, SDSS pre-burst observations
  93. GRB 050813: Swift-BAT refined analysis
  94. GRB 050813: Photometry of object in XRT error circle
  95. GRB050813: SWIFT/UVOT observation
  96. GRB 050813: Swift XRT afterglow localization
  97. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  98. Detection of an intermediate burst from SGR 1806-20 on August 8
  99. GRB050805b: CrAO optical limit
  100. GRB050803, optical observations

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