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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"

45463 results found.

  1. Swift-BAT trigger 160619 is not a GRB
  2. Swift-BAT triggered on a posible CR Shower or possible GRB
  3. GRB 050502b: Optical limit
  4. GRB 051016b: Optical limit
  5. Afterglow candidate of GRB 051016B observed at Lulin
  6. GRB 051016b: Gemini Near IR Observations
  7. GRB 051016A: Swift/UVOT upper limits
  8. GRB 051016B: refined analysis of the Swift/XRT data
  9. GRB 051016B: Swift/UVOT detection
  10. GRB 051016B,optical observation
  11. GRB 051016B : Optical follow-up at Lulin
  12. GRB 051016B: Refined analysis of the Swift-BAT burst
  13. GRB 051016B: Swift detection of a soft burst
  14. GRB 051016: Swift-BAT refined analysis
  15. GRB051016 XMM-Newton observation
  16. GRB051016: Swift XRT refined analysis.
  17. GRB051016: Planned XMM-Newton observation
  18. GRB 051016: LCO optical and near-IR imaging
  19. GRB 051016: PROMPT Observations
  20. GRB051016: Swift detection of a burst
  21. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  22. GRB051006: optical observations
  23. GRB 051012: Swift-BAT detection of burst yesterday
  24. Swift trigger 159578 is not a burst
  25. Swift-BAT Trigger 159578 is a possible burst
  26. GRB050805A: Rc optical observations
  27. GRB 051006: Swift/UVOT Upper Limits
  28. IBAS Alert 2675 : not a GRB
  29. GRB051008: optical candidate
  30. GRB 051008: - a high redshift high-luminosity burst?
  31. GRB 051008 - a low redshift low-luminosity burst?
  32. IBAS Alert 2673: not a real GRB
  33. GRB051011: bright nebulae near error box
  34. GRB051008: optical observation
  35. GRB051008: Swift XRT refined analysis
  36. GRB051008 - Swift UVOT upper limits
  37. Konus-Wind observation of GRB 051008
  38. GRB051008: Final refined analysis of the Swift-BAT burst
  39. GRB 051008: R-band upper limit
  40. GRB051008: Refined analysis of the Swift-BAT burst
  41. GRB051008: Radio Observation
  42. GRB 051008: Swift XRT position
  43. GRB 051008, optical observations
  44. GRB 051008: early Swift XRT analysis
  45. GRB 051008: Swift UVOT Candidate
  46. GRB051008: Swift-BAT detection of a bright burst
  47. GRB 051006: P60 Observations
  48. grb test
  49. GRB 051006: XRT refined analysis
  50. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  51. GRB 051006: optical observations at Sierra Nevada
  52. GRB051006: Refined analysis of the Swift-BAT burst
  53. GRB 051006: XRT position
  54. GRB051006: Swift detection of a burst
  55. GRB 050906, summary of radio observations
  56. Swift-BAT triggers 158261 and 158262 Retraction
  57. GRB051001: Swift UVOT Upper Limits
  58. GRB 050925: Second Epoch WSRT Radio Observations
  59. GRB 051001: Swift XRT refined analysis
  60. GRB 051001, optical observations at Mt. John
  61. GRB 051001: I-band limit
  62. GRB 051001: AAT infra-red observations
  63. GRB 051001: Swift-BAT refined analysis
  64. GRB 051001: Swift Detection of a Burst
  65. GRB 051001: ROTSE-III Optical Limits
  66. GRB050908: optical observations
  67. GRB050922C: optical observation
  68. GRB050922B: optical limit
  69. GRB 050922C: further VLT observations
  70. GRB 050820A: NIR photometry at the TNG
  71. GRB050922C: UVES/VLT high resolution spectroscopy
  72. GRB050925: Swift/XRT limits
  73. GRB/SGR 050925: IR Observations
  74. GRB050922C - Swift UVOT preliminary analysis
  75. GRB 050922C: break in the lightcurve
  76. GRB 050925: WSRT Radio Observations
  77. GRB050925: Swift UVOT upper limits
  78. Refined analysis of the Swift-BAT soft short burst
  79. GRB 050925 : I-band observation at Xinglong observatory
  80. GRB050925: Faulkes Telescope North R-band limit
  81. GRB050925: Swift-BAT detection of a short burst
  82. GRB 050922B: Correction to BAT refined analysis, longer burst
  83. GRB050922C: TNG spectroscopic observations
  84. GRB050922B: refined XRT analysis
  85. Konus-Wind observation of GRB 050922C
  86. GRB 050922C: Refined redshift
  87. GRB050922B: Swift UVOT early upper limits.
  88. GRB OT observation
  89. GRB050922C: observation at MonteBoo
  90. INT 2.5m limit for GRB050922B
  91. GRB 050922B: optical limit
  92. GRB050922C: Optical Observations
  93. GRB 050922C: Swift XRT refined analysis
  94. HETE Fregate observations of GRB 050922C
  95. GRB 050922C: Swift-BAT refined analysis
  96. GRB 050922B: Swift-BAT refined analysis
  97. GRB050922C: optical observations
  98. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  99. GRB 050922C: optical obserations
  100. GRB 050922C: NOT optical observations

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