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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"

28095 results found.

  1. GRB 050911: z~0.16 cluster in the field
  2. GRB050911: Swift-BAT detection of a long burst
  3. GRB 050910a: TAROT early optical limits
  4. WIRO observations in I of GRB 050908
  5. GRB 050906: Possible X-ray Counterpart
  6. GRB050908: Swift/UVOT Early upper limits
  7. GRB050908 : Swift-XRT refined analysis
  8. GRB 050908: Swift-BAT refined analysis
  9. GRB 050908: Optical observations
  10. GRB 050908: Optical Observations
  11. GRB 050908: Swift detection of a burst
  12. GRB 050906: Optical observations at the Very Large Telescope
  13. GRB 050904 BAT refined analysis of complete data set
  14. GRB 050904: Subaru Optical Spectroscopy
  15. GRB 050906: MARGE Optical Limits
  16. GRB 050906: Swift-BAT refined analysis
  17. GRB 050906: Swift XRT upper limit
  18. GRB 050906: Radio Observations
  19. GRB 050904: Keck I-band Imaging
  20. GRB050906: P60 Observations
  21. GRB 050904: more VLT NIR observations
  22. GRB 050904: photometric redshift
  23. GRB 050904: Swift/UVOT observations
  24. GRB 050904: NIR object inside the XRT error box
  25. GRB 050904: early Swift XRT analysis results
  26. GRB 050904: SOAR YJ and PROMPT Ic Observations
  27. GRB050904: Optical Observations
  28. GRB050904: P60 Observations
  29. GRB 050904: TAROT optical limits
  30. GRB 050827 : OSN 1.5m optical observations
  31. GRB 050827: P200 NIR Observations
  32. GRB050827: Swift/UVOT upper limits
  33. GRB 050827: Optical Limit
  34. GRB 050827: XRT possible afterglow detection
  35. GRB 050826 : Lulin R band observation
  36. GRB050824: Maidanak optical limits
  37. GRB 050827: Swift-BAT refined analysis
  38. Subaru Observations of GRB050724
  39. GRB 050826: Optical Candidate
  40. GRB 050826: Swift XRT preliminary analysis results
  41. GRB 050826: BAT refined analysis
  42. GRB050826: Swift/UVOT early upper limits
  43. GRB050826: Swift-BAT detection of a long burst
  44. GRB050824: MASTER final analysis of the OT observations
  45. Swift-BAT trigger 152038 is probably not a GRB
  46. GRB 050824: XRT refined analysis and possible afterglow detection
  47. GRB 050824: BAT refined analysis of a soft weak burst
  48. GRB050824: MASTER:OT decay
  49. GRB050824: MASTER observation OT
  50. GRB050805a: MASTER optical candidat
  51. XRF050509c: Radio upper limits from GMRT
  52. GRB050822: Swift/UVOT upper limits
  53. GRB 050820A BAT observations of second, larger episode of emission
  54. GRB050813: Maidanak I-band observations
  55. GRB 050822: Swift-BAT refined analysis
  56. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  57. GRB050820B at FRAM
  58. Swift/UVOT UV Photometry of GRB 050820B
  59. GRB 050822: Swift detection of a long burst
  60. GRB050820a BVRcIc field photometry
  61. GRB050820B XMM-Newton observation
  62. GRB 050820a: NIR Observations by WIRO
  63. GRB 050820B: Swift XRT position
  64. GRB050820B: Refined analysis of the Swift-BAT burst
  65. GRB050820: refined XRT analysis
  66. GRB 050820 Swift-BAT refined analysis
  67. GRB050819: refined XRT analysis
  68. GRB 050820: Swift detection of a GRB
  69. GRB 050819 Swift-BAT refined analysis
  70. GRB050819: Swift-BAT detection of a weak burst
  71. GRB 050817: Optical observations
  72. GRB050817: Negative Optical Observations
  73. GRB 050814: continued fading
  74. GRB050815: Optical afterglow detection by Swift UVOT
  75. GRB050815: XRT refined analysis
  76. GRB050815: Refined analysis of the Swift-BAT burst
  77. GRB 050815: ROTSE-III Optical Limits
  78. GRB050815: Swift-BAT detection of a burst
  79. GRB050814: Fading red source
  80. GRB050814: P60 Optical Afterglow Candidate
  81. GRB 050813: Non-fading of afterglow candidate
  82. GRB 050814: XRT refined analysis
  83. GRB050814: SWIFT/UVOT observation
  84. GRB050814: Refined analysis of the Swift-BAT burst
  85. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  86. GRB 050814: Swift XRT Afterglow Localization
  87. GRB 050814: Swift detection of a burst
  88. GRB 050813: Magellan detection of a high redshift galaxy cluster
  89. GRB050813, SDSS pre-burst observations
  90. GRB 050813: Swift-BAT refined analysis
  91. GRB 050813: Photometry of object in XRT error circle
  92. GRB050813: SWIFT/UVOT observation
  93. GRB 050813: Swift XRT afterglow localization
  94. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  95. Detection of an intermediate burst from SGR 1806-20 on August 8
  96. GRB050805b: CrAO optical limit
  97. GRB050803, optical observations
  98. Retraction of Swift Trigger 149131 (GRB 050805B)
  99. GRB 050805b: OHP optical limits
  100. GRB 050805b: TAROT optical limits

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