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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"

42173 results found.

  1. GRB 051021B: Swift detection of a burst
  2. GRB051021: Swift XRT analysis
  3. GRB051021 (=H3947): Refined Analysis
  4. GRB 051021 : optical afterglow observation at Lulin
  5. GRB 051021: Optical observations
  6. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  7. GRB 051021: Optical observations and candidate afterglow
  8. GRB051021.63
  9. GRB051021.6: MASTER optical observation
  10. Swift-BAT trigger 160640 is not a real GRB
  11. GRB051021: A GRB Localized by HETE
  12. GRB 050502b: Optical limit
  13. GRB 051016b: Optical limit
  14. Afterglow candidate of GRB 051016B observed at Lulin
  15. GRB 051016b: Gemini Near IR Observations
  16. GRB 051016A: Swift/UVOT upper limits
  17. GRB 051016B: refined analysis of the Swift/XRT data
  18. GRB 051016B: Swift/UVOT detection
  19. GRB 051016B,optical observation
  20. GRB 051016B : Optical follow-up at Lulin
  21. GRB 051016B: Refined analysis of the Swift-BAT burst
  22. GRB 051016B: Swift detection of a soft burst
  23. GRB051016 XMM-Newton observation
  24. GRB051016: Swift XRT refined analysis.
  25. GRB051016: Planned XMM-Newton observation
  26. GRB 051016: LCO optical and near-IR imaging
  27. GRB051016: Swift detection of a burst
  28. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  29. GRB051006: optical observations
  30. GRB 051012: Swift-BAT detection of burst yesterday
  31. Swift-BAT Trigger 159578 is a possible burst
  32. GRB050805A: Rc optical observations
  33. GRB 051006: Swift/UVOT Upper Limits
  34. GRB051008: optical candidate
  35. GRB 051008 - a low redshift low-luminosity burst?
  36. GRB051011: MASTER optical observation
  37. GRB051008: optical observation
  38. GRB051008: Swift XRT refined analysis
  39. GRB051008 - Swift UVOT upper limits
  40. Konus-Wind observation of GRB 051008
  41. GRB051008: Final refined analysis of the Swift-BAT burst
  42. GRB 051008: R-band upper limit
  43. GRB051008: Refined analysis of the Swift-BAT burst
  44. GRB051008: Radio Observation
  45. GRB 051008: Swift XRT position
  46. GRB 051008, optical observations
  47. GRB 051008: Swift UVOT Candidate
  48. GRB051008: Swift-BAT detection of a bright burst
  49. GRB 051006: P60 Observations
  50. GRB 051006: XRT refined analysis
  51. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  52. GRB 051006: optical observations at Sierra Nevada
  53. GRB051006: Refined analysis of the Swift-BAT burst
  54. GRB 051006: XRT position
  55. GRB051006: Swift detection of a burst
  56. GRB 050906, summary of radio observations
  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. GRB050922C: TNG spectroscopic observations
  83. GRB050922B: refined XRT analysis
  84. Konus-Wind observation of GRB 050922C
  85. GRB050922B: Swift UVOT early upper limits.
  86. GRB OT observation
  87. GRB050922C: observation at MonteBoo
  88. INT 2.5m limit for GRB050922B
  89. GRB 050922B: optical limit
  90. GRB050922C: Optical Observations
  91. GRB 050922C: Swift XRT refined analysis
  92. HETE Fregate observations of GRB 050922C
  93. GRB 050922C: Swift-BAT refined analysis
  94. GRB050922C: optical observations
  95. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  96. GRB 050922C: optical obserations
  97. GRB 050922C: NOT optical observations
  98. GRB 050922C: Swift detection of a bright burst
  99. GRB 050922C: ROTSE-IIId Refined Analysis
  100. GRB 050922C: ROTSE-III Detection of Possible Counterpart

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