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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"

15710 results found.

  1. HETE Fregate observations of GRB 050922C
  2. GRB050922C: optical observations
  3. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  4. GRB 050922C: optical obserations
  5. GRB 050922C: NOT optical observations
  6. GRB 050922C: Swift detection of a bright burst
  7. GRB 050922B: ROTSE-III Optical Limits
  8. GRB 050922B,optical observation
  9. GRB050820B: analysis of the XMM-Newton observation
  10. GRB 050915b, SMARTS optical/IR observations of the XRT position
  11. GRB 050915b, SMARTS optical/IR observations
  12. GRB 050915: KAIT optical limit
  13. GRB050915: P60 Optical Observations
  14. GRB050915, optical observations
  15. GRB 050915: ROTSE-III optical limits
  16. GRB 050911, optical content of Swift/XRT error box
  17. GRB 050911, optical observations
  18. GRB050908: detection of Swift/UVOT optical counterpart
  19. GRB 050910a: TAROT early optical limits
  20. GRB 050906: RTT150 optical observations
  21. GRB050908: Swift/UVOT Early upper limits
  22. GRB050908: VLT R-band decay index.
  23. GRB050908 : Swift-XRT refined analysis
  24. GRB 050908: Swift-BAT refined analysis
  25. GRB 050908: Optical observations
  26. Gemini Spectroscopy of GRB 050908
  27. GRB 050908: spectroscopic redshift
  28. GRB 050908 : Swift XRT position
  29. GRB 050908: P60 Confirmation of Optical Afterglow
  30. GRB 050908: Optical Observations
  31. GRB 050906: Optical observations at the Very Large Telescope
  32. GRB050904: CrAO optical observations
  33. GRB 050904: Subaru Optical Spectroscopy
  34. GRB 050906: MARGE Optical Limits
  35. GRB 050904: more VLT NIR observations
  36. GRB 050906: Swift/BAT Detection of a possible burst
  37. GRB 050904: More SOAR
  38. GRB 050904: Swift/UVOT observations
  39. GRB 050904: SOAR YJ and PROMPT Ic Observations
  40. GRB 050904: BAT refined analysis of partial data set
  41. GRB 050904: TAROT optical measurements
  42. GRB050904: Optical Observations
  43. GRB 050904: Possible High-Redshift GRB
  44. GRB 050904: TAROT optical limits
  45. GRB050904: Swift-BAT detection of a probable burst
  46. GRB 050824: MDM Observations
  47. GRB 050827 : OSN 1.5m optical observations
  48. GRB 050827: Optical Limit
  49. GRB 050826 : Lulin R band observation
  50. GRB050824: Maidanak optical limits
  51. GRB050820A: RTT150 optical observations
  52. GRB050827: RTT150 optical observations
  53. Subaru Observations of GRB050724
  54. GRB 050826: Optical Candidate
  55. GRB050824, HETE-2 Observation
  56. GRB050826: Swift/UVOT early upper limits
  57. GRB050824: First 2 hours of power low optical decay?
  58. Possible GRB050825:MASTER optical observations
  59. GRB050824: CORRECTION to UVOT observing times
  60. GRB050824: Swift/UVOT detection of fading afterglow
  61. GRB050824, I-band imaging
  62. GRB050824: Radio Observations
  63. GRB 050824: XRT refined analysis and possible afterglow detection
  64. GRB 050824: BAT refined analysis of a soft weak burst
  65. GRB050824: MASTER:OT decay
  66. GRB050805a: MASTER optical candidat
  67. GRB 050824: ROTSE-III Optical Limits
  68. GRB 050824 optical candidate
  69. GRB050820A: RTT150 optical observations
  70. GRB050815: Maidanak optical observation
  71. VLT/UVES spectroscopy of GRB050820
  72. GRB050820B at FRAM
  73. GRB050820A: RTT150 optical observations
  74. GRB 050820a - corrections to GCN 3846
  75. GRB 050822: ROTSE-III Prompt Optical Limits
  76. GRB050820A: Radio Observation
  77. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  78. GRB050820a BVRcIc field photometry
  79. GRB050820: refined XRT analysis
  80. GRB 050820 Swift-BAT refined analysis
  81. GRB 050820: P60 Temporal Decay Index
  82. GRB 050820: High Resolution Spectroscopy from Keck
  83. GRB050819: RTT150 optical observations
  84. GRB050820: Optical afterglow from P60
  85. GRB 050817: Optical observations
  86. GRB 050815: Radio Observation
  87. GRB050814: Radio Observation
  88. GRB050817: Negative Optical Observations
  89. GRB050817: Swift-BAT Detection of a burst
  90. GRB 050814: continued fading
  91. GRB050815: Optical afterglow detection by Swift UVOT
  92. GRB 050815: ROTSE-III Optical Limits
  93. GRB050814: Fading red source
  94. GRB050814: P60 Optical Afterglow Candidate
  95. GRB050813: RTT150 optical observations
  96. GRB 050813: KAIT optical limit
  97. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  98. GRB050803: CrAO optical observations, no OT candidate
  99. GRB 050807: ROTSE-III Optical Limits
  100. GRB 050730, optical observation

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