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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"

15987 results found.

  1. GRB050925: Swift UVOT upper limits
  2. GRB050922C: TNG spectroscopic observations
  3. GRB050922B: Swift UVOT early upper limits.
  4. GRB OT observation
  5. GRB050922C: observation at MonteBoo
  6. GRB 050922B: optical limit
  7. GRB050922C: Optical Observations
  8. GRB 050922C: Swift XRT refined analysis
  9. HETE Fregate observations of GRB 050922C
  10. GRB050922C: optical observations
  11. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  12. GRB 050922C: optical obserations
  13. GRB 050922C: NOT optical observations
  14. GRB 050922C: Swift detection of a bright burst
  15. GRB 050922B: ROTSE-III Optical Limits
  16. GRB 050922B,optical observation
  17. GRB050820B: analysis of the XMM-Newton observation
  18. GRB 050915b, SMARTS optical/IR observations of the XRT position
  19. GRB 050915b, SMARTS optical/IR observations
  20. GRB 050915: KAIT optical limit
  21. GRB050915: P60 Optical Observations
  22. GRB050915, optical observations
  23. GRB 050915: ROTSE-III optical limits
  24. GRB 050911, optical content of Swift/XRT error box
  25. GRB 050911, optical observations
  26. GRB050908: detection of Swift/UVOT optical counterpart
  27. GRB 050910a: TAROT early optical limits
  28. GRB 050906: RTT150 optical observations
  29. GRB050908: Swift/UVOT Early upper limits
  30. GRB050908: VLT R-band decay index.
  31. GRB050908 : Swift-XRT refined analysis
  32. GRB 050908: Swift-BAT refined analysis
  33. GRB 050908: Optical observations
  34. Gemini Spectroscopy of GRB 050908
  35. GRB 050908: spectroscopic redshift
  36. GRB 050908 : Swift XRT position
  37. GRB 050908: P60 Confirmation of Optical Afterglow
  38. GRB 050908: Optical Observations
  39. GRB 050906: Optical observations at the Very Large Telescope
  40. GRB050904: CrAO optical observations
  41. GRB 050904: Subaru Optical Spectroscopy
  42. GRB 050906: MARGE Optical Limits
  43. GRB 050906: Swift/BAT Detection of a possible burst
  44. GRB 050904: SOAR YJ and PROMPT Ic Observations
  45. GRB 050904: TAROT optical measurements
  46. GRB050904: Optical Observations
  47. GRB 050904: TAROT optical limits
  48. GRB050904: Swift-BAT detection of a probable burst
  49. GRB 050824: MDM Observations
  50. GRB 050827 : OSN 1.5m optical observations
  51. GRB 050827: Optical Limit
  52. GRB 050826 : Lulin R band observation
  53. GRB050824: Maidanak optical limits
  54. GRB050820A: RTT150 optical observations
  55. GRB050827: RTT150 optical observations
  56. Subaru Observations of GRB050724
  57. GRB 050826: Optical Candidate
  58. GRB050824, HETE-2 Observation
  59. GRB050826: Swift/UVOT early upper limits
  60. GRB050824: First 2 hours of power low optical decay?
  61. Possible GRB050825:MASTER optical observations
  62. GRB050824: CORRECTION to UVOT observing times
  63. GRB050824: Swift/UVOT detection of fading afterglow
  64. GRB050824, I-band imaging
  65. GRB050824: Radio Observations
  66. GRB 050824: XRT refined analysis and possible afterglow detection
  67. GRB 050824: BAT refined analysis of a soft weak burst
  68. GRB050805a: MASTER optical candidat
  69. GRB 050824: ROTSE-III Optical Limits
  70. GRB 050824 optical candidate
  71. GRB050820A: RTT150 optical observations
  72. GRB050815: Maidanak optical observation
  73. VLT/UVES spectroscopy of GRB050820
  74. GRB050820B at FRAM
  75. GRB050820A: RTT150 optical observations
  76. GRB 050820a - corrections to GCN 3846
  77. GRB 050822: ROTSE-III Prompt Optical Limits
  78. GRB050820A: Radio Observation
  79. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  80. GRB050820a BVRcIc field photometry
  81. GRB050820: refined XRT analysis
  82. GRB 050820 Swift-BAT refined analysis
  83. GRB 050820: High Resolution Spectroscopy from Keck
  84. GRB050819: RTT150 optical observations
  85. GRB050820: Optical afterglow from P60
  86. GRB 050817: Optical observations
  87. GRB 050815: Radio Observation
  88. GRB050814: Radio Observation
  89. GRB050817: Negative Optical Observations
  90. GRB050817: Swift-BAT Detection of a burst
  91. GRB 050814: continued fading
  92. GRB050815: Optical afterglow detection by Swift UVOT
  93. GRB 050815: ROTSE-III Optical Limits
  94. GRB050814: Fading red source
  95. GRB050814: P60 Optical Afterglow Candidate
  96. GRB050813: RTT150 optical observations
  97. GRB 050813: KAIT optical limit
  98. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  99. GRB050803: CrAO optical observations, no OT candidate
  100. GRB 050807: ROTSE-III Optical Limits

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