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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"

33844 results found.

  1. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  2. GRB 051021: Optical observations and candidate afterglow
  3. GRB051021.63
  4. GRB051021.6: MASTER optical observation
  5. Swift-BAT trigger 160640 is not a real GRB
  6. GRB051021: A GRB Localized by HETE
  7. Swift-BAT trigger 160619 is not a GRB
  8. Swift-BAT triggered on a posible CR Shower or possible GRB
  9. GRB 050502b: Optical limit
  10. GRB 051016b: Optical limit
  11. Afterglow candidate of GRB 051016B observed at Lulin
  12. GRB 051016b: Gemini Near IR Observations
  13. GRB 051016A: Swift/UVOT upper limits
  14. GRB 051016B: refined analysis of the Swift/XRT data
  15. GRB 051016B: Swift/UVOT detection
  16. GRB 051016B,optical observation
  17. GRB 051016B : Optical follow-up at Lulin
  18. GRB 051016B: Refined analysis of the Swift-BAT burst
  19. GRB 051016B: Swift detection of a soft burst
  20. GRB 051016: Swift-BAT refined analysis
  21. GRB051016: Swift XRT refined analysis.
  22. GRB 051016: LCO optical and near-IR imaging
  23. GRB 051016: PROMPT Observations
  24. GRB051016: Swift detection of a burst
  25. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  26. GRB051006: optical observations
  27. GRB 051012: Swift-BAT detection of burst yesterday
  28. Swift trigger 159578 is not a burst
  29. GRB 051006: Swift/UVOT Upper Limits
  30. IBAS Alert 2675 : not a GRB
  31. GRB051008: optical candidate
  32. GRB 051008: - a high redshift high-luminosity burst?
  33. GRB 051008 - a low redshift low-luminosity burst?
  34. IBAS Alert 2673: not a real GRB
  35. GRB051011: MASTER optical observation
  36. GRB051008: optical observation
  37. GRB051008: Swift XRT refined analysis
  38. GRB051008 - Swift UVOT upper limits
  39. Konus-Wind observation of GRB 051008
  40. GRB051008: Final refined analysis of the Swift-BAT burst
  41. GRB 051008: R-band upper limit
  42. GRB051008: Radio Observation
  43. GRB 051008: Swift XRT position
  44. GRB 051008, optical observations
  45. GRB 051008: early Swift XRT analysis
  46. GRB 051008: Swift UVOT Candidate
  47. GRB 051006: P60 Observations
  48. grb test
  49. GRB 051006: XRT refined analysis
  50. GRB 051006: optical observations at Sierra Nevada
  51. GRB 051006: XRT position
  52. GRB 050906, summary of radio observations
  53. GRB 050925: Second Epoch WSRT Radio Observations
  54. GRB 051001: Swift XRT refined analysis
  55. GRB 051001, optical observations at Mt. John
  56. GRB 051001: I-band limit
  57. GRB 051001: AAT infra-red observations
  58. GRB 051001: Swift-BAT refined analysis
  59. GRB 051001: Swift Detection of a Burst
  60. GRB 051001: ROTSE-III Optical Limits
  61. GRB050908: optical observations
  62. GRB050922C: optical observation
  63. GRB050922B: optical limit
  64. GRB 050922C: further VLT observations
  65. GRB 050820A: NIR photometry at the TNG
  66. GRB050922C: UVES/VLT high resolution spectroscopy
  67. GRB050925: Swift/XRT limits
  68. GRB/SGR 050925: IR Observations
  69. GRB 050922C: break in the lightcurve
  70. GRB 050925: WSRT Radio Observations
  71. GRB 050925 : I-band observation at Xinglong observatory
  72. GRB050925: Faulkes Telescope North R-band limit
  73. GRB050925: Swift-BAT detection of a short burst
  74. GRB 050922B: Correction to BAT refined analysis, longer burst
  75. GRB050922C: TNG spectroscopic observations
  76. GRB050922B: refined XRT analysis
  77. Konus-Wind observation of GRB 050922C
  78. GRB 050922C: Refined redshift
  79. GRB OT observation
  80. GRB050922C: observation at MonteBoo
  81. INT 2.5m limit for GRB050922B
  82. GRB 050922B: optical limit
  83. GRB050922C: Optical Observations
  84. GRB 050922C: Swift XRT refined analysis
  85. HETE Fregate observations of GRB 050922C
  86. GRB 050922C: Swift-BAT refined analysis
  87. GRB 050922B: Swift-BAT refined analysis
  88. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  89. GRB 050922C: optical obserations
  90. GRB 050922C: NOT optical observations
  91. GRB 050922A: Analysis of Swift/XRT TOO observation
  92. GRB 050922C: Swift detection of a bright burst
  93. GRB 050922C: ROTSE-IIId Refined Analysis
  94. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  95. GRB 050922B: ROTSE-III Optical Limits
  96. GRB 050922B,optical observation
  97. GRB050922B: Swift-BAT detection of a weak long burst
  98. Possible GRB 050922 detected by INTEGRAL
  99. GRB050820B: analysis of the XMM-Newton observation
  100. GRB050916: Swift/UVOT Upper Limits

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