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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"

20604 results found.

  1. GRB 051022: SSO40 Optical Observations
  2. GRB051022,optical observation
  3. GRB 051022A: ROTSE-III Optical Limits
  4. GRB 051022: Optical observations
  5. GRB 051021,optical observation
  6. GRB 051021B: Swift detection of a burst
  7. Swift-BAT triggered on a posible CR Shower or possible GRB
  8. Afterglow candidate of GRB 051016B observed at Lulin
  9. GRB 051016A: Swift/UVOT upper limits
  10. GRB 051016B: Swift/UVOT detection
  11. GRB 051016B,optical observation
  12. GRB 051016B: Swift detection of a soft burst
  13. GRB051016 XMM-Newton observation
  14. GRB 051016: PROMPT Observations
  15. GRB051016: Swift detection of a burst
  16. GRB051006: optical observations
  17. GRB 051012: Swift-BAT detection of burst yesterday
  18. GRB 051006: Swift/UVOT Upper Limits
  19. GRB051011: MASTER optical observation
  20. Konus-Wind observation of GRB 051008
  21. GRB051008: Radio Observation
  22. GRB 051008, optical observations
  23. GRB 051008: early Swift XRT analysis
  24. GRB 051008: Swift UVOT Candidate
  25. GRB 051006: P60 Observations
  26. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  27. GRB051006: Refined analysis of the Swift-BAT burst
  28. GRB051006: Swift detection of a burst
  29. GRB 050906, summary of radio observations
  30. GRB051001: Swift UVOT Upper Limits
  31. GRB 051001: AAT infra-red observations
  32. GRB 051001: Swift Detection of a Burst
  33. GRB 051001: ROTSE-III Optical Limits
  34. GRB 050820A: NIR photometry at the TNG
  35. GRB/SGR 050925: IR Observations
  36. GRB050925: Swift UVOT upper limits
  37. GRB050925: Faulkes Telescope North R-band limit
  38. GRB050925: Swift-BAT detection of a short burst
  39. GRB050922C: TNG spectroscopic observations
  40. Konus-Wind observation of GRB 050922C
  41. GRB050922B: Swift UVOT early upper limits.
  42. GRB050922C: Optical Observations
  43. GRB 050922C: Swift-BAT refined analysis
  44. GRB 050922C: optical obserations
  45. GRB 050922C: NOT optical observations
  46. GRB 050922C: Swift detection of a bright burst
  47. GRB 050922C: ROTSE-IIId Refined Analysis
  48. GRB 050922B: ROTSE-III Optical Limits
  49. GRB 050922B,optical observation
  50. GRB050922B: Swift-BAT detection of a weak long burst
  51. GRB050918: Possible Swift/XRT detected afterglow
  52. GRB050820B: analysis of the XMM-Newton observation
  53. GRB050916: Swift/UVOT Upper Limits
  54. Swift-BAT trigger 155764 is not a GRB
  55. Swift-BAT trigger 155764 is probably not a GRB
  56. Swift trigger 155764: bad XRT centroid
  57. Swift-BAT trigger 155535 is definitely not a GRB
  58. GRB050916 : Swift-XRT refined analysis
  59. GRB 050915B: Swift/UVOT Upper Limits
  60. GRB 050915a: IR Transient
  61. GRB 050915b, SMARTS optical/IR observations
  62. GRB050915B: Swift-BAT detection of a long bright burst
  63. GRB050915: Swift/UVOT upper limits
  64. GRB 050915: IR Observations
  65. GRB 050915: ROTSE-III optical limits
  66. GRB 050915: Swift detection of a GRB
  67. Swift-BAT trigger 155072 ground analysis
  68. Swift-BAT trigger 155072 is probably not a GRB
  69. GRB 050911, optical observations
  70. GRB 050911: z~0.16 cluster in the field
  71. GRB050911: Swift-BAT detection of a long burst
  72. GRB 050910a: TAROT early optical limits
  73. GRB 050906: Possible X-ray Counterpart
  74. GRB050908: Swift/UVOT Early upper limits
  75. GRB050908 : Swift-XRT refined analysis
  76. GRB 050908: Optical observations
  77. GRB 050908: Optical Observations
  78. GRB 050908: Swift detection of a burst
  79. GRB 050906: Optical observations at the Very Large Telescope
  80. GRB 050904: Subaru Optical Spectroscopy
  81. GRB 050906: Swift XRT upper limit
  82. GRB 050904: Keck I-band Imaging
  83. GRB050906: P60 Observations
  84. GRB 050904: photometric redshift
  85. GRB 050904: Swift/UVOT observations
  86. GRB 050904: NIR object inside the XRT error box
  87. GRB050904: Optical Observations
  88. GRB050904: P60 Observations
  89. GRB 050904: TAROT optical limits
  90. GRB 050827: P200 NIR Observations
  91. GRB050827: Swift/UVOT upper limits
  92. GRB050824: Maidanak optical limits
  93. GRB050820A: RTT150 optical observations
  94. Subaru Observations of GRB050724
  95. GRB050826: Swift/UVOT early upper limits
  96. GRB050826: Swift-BAT detection of a long burst
  97. GRB050824: CORRECTION to UVOT observing times
  98. GRB050824: Swift/UVOT detection of fading afterglow
  99. GRB 050824: BAT refined analysis of a soft weak burst
  100. GRB050824: MASTER observation OT

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