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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"

28082 results found.

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

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