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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"

15993 results found.

  1. GRB050922C: optical observation
  2. GRB050922B: optical limit
  3. GRB 050922C: further VLT observations
  4. GRB050922C: UVES/VLT high resolution spectroscopy
  5. GRB050922C - Swift UVOT preliminary analysis
  6. GRB 050922C: break in the lightcurve
  7. GRB050925: Swift UVOT upper limits
  8. GRB050922C: TNG spectroscopic observations
  9. GRB050922B: Swift UVOT early upper limits.
  10. GRB OT observation
  11. GRB050922C: observation at MonteBoo
  12. GRB 050922B: optical limit
  13. GRB050922C: Optical Observations
  14. GRB 050922C: Swift XRT refined analysis
  15. HETE Fregate observations of GRB 050922C
  16. GRB050922C: optical observations
  17. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  18. GRB 050922C: optical obserations
  19. GRB 050922C: NOT optical observations
  20. GRB 050922C: Swift detection of a bright burst
  21. GRB 050922B: ROTSE-III Optical Limits
  22. GRB 050922B,optical observation
  23. GRB050820B: analysis of the XMM-Newton observation
  24. GRB 050915b, SMARTS optical/IR observations of the XRT position
  25. GRB 050915b, SMARTS optical/IR observations
  26. GRB 050915: KAIT optical limit
  27. GRB050915: P60 Optical Observations
  28. GRB050915, optical observations
  29. GRB 050915: ROTSE-III optical limits
  30. GRB 050911, optical content of Swift/XRT error box
  31. GRB 050911, optical observations
  32. GRB050908: detection of Swift/UVOT optical counterpart
  33. GRB 050910a: TAROT early optical limits
  34. GRB 050906: RTT150 optical observations
  35. GRB050908: Swift/UVOT Early upper limits
  36. GRB050908: VLT R-band decay index.
  37. GRB050908 : Swift-XRT refined analysis
  38. GRB 050908: Swift-BAT refined analysis
  39. GRB 050908: Optical observations
  40. Gemini Spectroscopy of GRB 050908
  41. GRB 050908: spectroscopic redshift
  42. GRB 050908 : Swift XRT position
  43. GRB 050908: P60 Confirmation of Optical Afterglow
  44. GRB 050908: Optical Observations
  45. GRB 050906: Optical observations at the Very Large Telescope
  46. GRB050904: CrAO optical observations
  47. GRB 050904: Subaru Optical Spectroscopy
  48. GRB 050906: MARGE Optical Limits
  49. GRB 050906: Swift/BAT Detection of a possible burst
  50. GRB 050904: SOAR YJ and PROMPT Ic Observations
  51. GRB 050904: TAROT optical measurements
  52. GRB050904: Optical Observations
  53. GRB 050904: TAROT optical limits
  54. GRB050904: Swift-BAT detection of a probable burst
  55. GRB 050824: MDM Observations
  56. GRB 050827 : OSN 1.5m optical observations
  57. GRB 050827: Optical Limit
  58. GRB 050826 : Lulin R band observation
  59. GRB050824: Maidanak optical limits
  60. GRB050820A: RTT150 optical observations
  61. GRB050827: RTT150 optical observations
  62. Subaru Observations of GRB050724
  63. GRB 050826: Optical Candidate
  64. GRB050824, HETE-2 Observation
  65. GRB050826: Swift/UVOT early upper limits
  66. GRB050824: First 2 hours of power low optical decay?
  67. Possible GRB050825:MASTER optical observations
  68. GRB050824: CORRECTION to UVOT observing times
  69. GRB050824: Swift/UVOT detection of fading afterglow
  70. GRB050824, I-band imaging
  71. GRB050824: Radio Observations
  72. GRB 050824: XRT refined analysis and possible afterglow detection
  73. GRB 050824: BAT refined analysis of a soft weak burst
  74. GRB050805a: MASTER optical candidat
  75. GRB 050824: ROTSE-III Optical Limits
  76. GRB 050824 optical candidate
  77. GRB050820A: RTT150 optical observations
  78. GRB050815: Maidanak optical observation
  79. VLT/UVES spectroscopy of GRB050820
  80. GRB050820B at FRAM
  81. GRB050820A: RTT150 optical observations
  82. GRB 050820a - corrections to GCN 3846
  83. GRB 050822: ROTSE-III Prompt Optical Limits
  84. GRB050820A: Radio Observation
  85. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  86. GRB050820a BVRcIc field photometry
  87. GRB050820: refined XRT analysis
  88. GRB 050820 Swift-BAT refined analysis
  89. GRB 050820: High Resolution Spectroscopy from Keck
  90. GRB050819: RTT150 optical observations
  91. GRB050820: Optical afterglow from P60
  92. GRB 050817: Optical observations
  93. GRB 050815: Radio Observation
  94. GRB050814: Radio Observation
  95. GRB050817: Negative Optical Observations
  96. GRB050817: Swift-BAT Detection of a burst
  97. GRB 050814: continued fading
  98. GRB050815: Optical afterglow detection by Swift UVOT
  99. GRB 050815: ROTSE-III Optical Limits
  100. GRB050814: Fading red source

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