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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').
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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"

42181 results found.

  1. GRB 051021B: Refined analysis of the Swift-BAT burst
  2. GRB 051022: SSO40 Optical Observations
  3. GRB051022,optical observation
  4. GRB 051022A: ROTSE-III Optical Limits
  5. GRB051022 (=H3590), A GRB Detected By HETE
  6. GRB 051022: Optical observations
  7. GRB 051021,optical observation
  8. GRB051021B: Swift XRT Position
  9. GRB 051021B: Swift detection of a burst
  10. GRB051021: Swift XRT analysis
  11. GRB051021 (=H3947): Refined Analysis
  12. GRB 051021 : optical afterglow observation at Lulin
  13. GRB 051021: Optical observations
  14. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  15. GRB 051021: Optical observations and candidate afterglow
  16. GRB051021.63
  17. GRB051021.6: MASTER optical observation
  18. Swift-BAT trigger 160640 is not a real GRB
  19. GRB051021: A GRB Localized by HETE
  20. GRB 050502b: Optical limit
  21. GRB 051016b: Optical limit
  22. Afterglow candidate of GRB 051016B observed at Lulin
  23. GRB 051016b: Gemini Near IR Observations
  24. GRB 051016A: Swift/UVOT upper limits
  25. GRB 051016B: refined analysis of the Swift/XRT data
  26. GRB 051016B: Swift/UVOT detection
  27. GRB 051016B,optical observation
  28. GRB 051016B : Optical follow-up at Lulin
  29. GRB 051016B: Refined analysis of the Swift-BAT burst
  30. GRB 051016B: Swift detection of a soft burst
  31. GRB051016 XMM-Newton observation
  32. GRB051016: Swift XRT refined analysis.
  33. GRB051016: Planned XMM-Newton observation
  34. GRB 051016: LCO optical and near-IR imaging
  35. GRB051016: Swift detection of a burst
  36. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  37. GRB051006: optical observations
  38. GRB 051012: Swift-BAT detection of burst yesterday
  39. Swift-BAT Trigger 159578 is a possible burst
  40. GRB050805A: Rc optical observations
  41. GRB 051006: Swift/UVOT Upper Limits
  42. GRB051008: optical candidate
  43. GRB 051008 - a low redshift low-luminosity burst?
  44. GRB051011: MASTER optical observation
  45. GRB051008: optical observation
  46. GRB051008: Swift XRT refined analysis
  47. GRB051008 - Swift UVOT upper limits
  48. Konus-Wind observation of GRB 051008
  49. GRB051008: Final refined analysis of the Swift-BAT burst
  50. GRB 051008: R-band upper limit
  51. GRB051008: Refined analysis of the Swift-BAT burst
  52. GRB051008: Radio Observation
  53. GRB 051008: Swift XRT position
  54. GRB 051008, optical observations
  55. GRB 051008: Swift UVOT Candidate
  56. GRB051008: Swift-BAT detection of a bright burst
  57. GRB 051006: P60 Observations
  58. GRB 051006: XRT refined analysis
  59. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  60. GRB 051006: optical observations at Sierra Nevada
  61. GRB051006: Refined analysis of the Swift-BAT burst
  62. GRB 051006: XRT position
  63. GRB051006: Swift detection of a burst
  64. GRB 050906, summary of radio observations
  65. GRB051001: Swift UVOT Upper Limits
  66. GRB 050925: Second Epoch WSRT Radio Observations
  67. GRB 051001: Swift XRT refined analysis
  68. GRB 051001, optical observations at Mt. John
  69. GRB 051001: I-band limit
  70. GRB 051001: AAT infra-red observations
  71. GRB 051001: Swift-BAT refined analysis
  72. GRB 051001: Swift Detection of a Burst
  73. GRB 051001: ROTSE-III Optical Limits
  74. GRB050908: optical observations
  75. GRB050922C: optical observation
  76. GRB050922B: optical limit
  77. GRB 050922C: further VLT observations
  78. GRB 050820A: NIR photometry at the TNG
  79. GRB050922C: UVES/VLT high resolution spectroscopy
  80. GRB050925: Swift/XRT limits
  81. GRB/SGR 050925: IR Observations
  82. GRB050922C - Swift UVOT preliminary analysis
  83. GRB 050922C: break in the lightcurve
  84. GRB 050925: WSRT Radio Observations
  85. GRB050925: Swift UVOT upper limits
  86. Refined analysis of the Swift-BAT soft short burst
  87. GRB 050925 : I-band observation at Xinglong observatory
  88. GRB050925: Faulkes Telescope North R-band limit
  89. GRB050925: Swift-BAT detection of a short burst
  90. GRB050922C: TNG spectroscopic observations
  91. GRB050922B: refined XRT analysis
  92. Konus-Wind observation of GRB 050922C
  93. GRB050922B: Swift UVOT early upper limits.
  94. GRB OT observation
  95. GRB050922C: observation at MonteBoo
  96. INT 2.5m limit for GRB050922B
  97. GRB 050922B: optical limit
  98. GRB050922C: Optical Observations
  99. GRB 050922C: Swift XRT refined analysis
  100. HETE Fregate observations of GRB 050922C

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