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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"

27402 results found.

  1. GRB 051022: Swift/UVOT Upper Limits
  2. GRB051022: Radio Counterpart
  3. GRB051022: IR observations
  4. GRB051021A: Swift XRT refined analysis
  5. GRB051022: Optical Observations
  6. GRB051021b: Magellan IR Imaging
  7. GRB 051021, SMARTS optical/IR observations
  8. GRB051022: Swift XRT Position
  9. GRB 051021: P200 Ks Observations
  10. GRB 051022 (=H3950): SXC Flight Localization is Valid
  11. GRB051021: Swift/UVOT Upper Limits
  12. GRB 051021B: Refined analysis of the Swift-BAT burst
  13. GRB 051022: SSO40 Optical Observations
  14. GRB051022,optical observation
  15. GRB 051021,optical observation
  16. GRB 051021B: Swift detection of a burst
  17. GRB 051021 : optical afterglow observation at Lulin
  18. GRB 051021: Optical observations and candidate afterglow
  19. GRB051021.63
  20. GRB051021.6: MASTER optical observation
  21. GRB051021: A GRB Localized by HETE
  22. Swift-BAT triggered on a posible CR Shower or possible GRB
  23. GRB 051016b: Optical limit
  24. Afterglow candidate of GRB 051016B observed at Lulin
  25. GRB 051016A: Swift/UVOT upper limits
  26. GRB 051016B: refined analysis of the Swift/XRT data
  27. GRB 051016B: Swift/UVOT detection
  28. GRB 051016B,optical observation
  29. GRB 051016B : Optical follow-up at Lulin
  30. GRB 051016B: Refined analysis of the Swift-BAT burst
  31. GRB 051016B: Swift detection of a soft burst
  32. GRB 051016: Swift-BAT refined analysis
  33. GRB051016 XMM-Newton observation
  34. GRB051016: Swift XRT refined analysis.
  35. GRB 051016: PROMPT Observations
  36. GRB051016: Swift detection of a burst
  37. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  38. GRB 051012: Swift-BAT detection of burst yesterday
  39. Swift-BAT Trigger 159578 is a possible burst
  40. GRB 051006: Swift/UVOT Upper Limits
  41. GRB051008: optical candidate
  42. GRB 051008 - a low redshift low-luminosity burst?
  43. GRB051011: bright nebulae near error box
  44. GRB051011: MASTER optical observation
  45. GRB051008: Final refined analysis of the Swift-BAT burst
  46. GRB051008: Radio Observation
  47. GRB 051008, optical observations
  48. GRB 051008: early Swift XRT analysis
  49. GRB 051008: Swift UVOT Candidate
  50. GRB 051006: P60 Observations
  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. GRB051006: Swift detection of a burst
  55. GRB 050906, summary of radio observations
  56. GRB051001: Swift UVOT Upper Limits
  57. GRB 050925: Second Epoch WSRT Radio Observations
  58. GRB 051001: I-band limit
  59. GRB 051001: AAT infra-red observations
  60. GRB 051001: Swift-BAT refined analysis
  61. GRB 051001: Swift Detection of a Burst
  62. GRB 050820A: NIR photometry at the TNG
  63. GRB050925: Swift/XRT limits
  64. GRB/SGR 050925: IR Observations
  65. GRB 050922C: break in the lightcurve
  66. GRB050925: Swift UVOT upper limits
  67. Refined analysis of the Swift-BAT soft short burst
  68. GRB050925: Faulkes Telescope North R-band limit
  69. GRB050925: Swift-BAT detection of a short burst
  70. GRB050922C: TNG spectroscopic observations
  71. GRB050922B: refined XRT analysis
  72. GRB050922B: Swift UVOT early upper limits.
  73. GRB050922C: Optical Observations
  74. GRB 050922C: Swift XRT refined analysis
  75. HETE Fregate observations of GRB 050922C
  76. GRB 050922C: Swift-BAT refined analysis
  77. GRB 050922B: Swift-BAT refined analysis
  78. GRB 050922C: optical obserations
  79. GRB 050922C: NOT optical observations
  80. GRB 050922C: Swift detection of a bright burst
  81. GRB 050922B: ROTSE-III Optical Limits
  82. GRB 050922B,optical observation
  83. GRB050922B: Swift-BAT detection of a weak long burst
  84. GRB050820B: analysis of the XMM-Newton observation
  85. GRB050916: Swift/UVOT Upper Limits
  86. GRB 050916: Swift-BAT refined analysis
  87. Swift-BAT trigger 155764 is not a GRB
  88. Swift-BAT trigger 155764 is probably not a GRB
  89. Swift trigger 155764: bad XRT centroid
  90. Swift-BAT trigger 155535 is definitely not a GRB
  91. GRB050916 : Swift-XRT refined analysis
  92. GRB 050915B: Swift-BAT refined analysis
  93. GRB 050915B: Swift/UVOT Upper Limits
  94. GRB 050915a: IR Transient
  95. GRB 050915b, SMARTS optical/IR observations
  96. GRB050915B: Swift-BAT detection of a long bright burst
  97. GRB050915: Swift/UVOT upper limits
  98. GRB 050915: IR Observations
  99. GRB 050915: Swift XRT refined analysis
  100. GRB 050915: Swift-BAT refined analysis

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