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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"
  1. GRB051016 XMM-Newton observation
  2. GRB051016: Swift XRT refined analysis.
  3. GRB051016: Planned XMM-Newton observation
  4. GRB 051016: LCO optical and near-IR imaging
  5. GRB 051016: PROMPT Observations
  6. GRB051016: Swift detection of a burst
  7. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  8. GRB051006: optical observations
  9. GRB 051012: Swift-BAT detection of burst yesterday
  10. Swift trigger 159578 is not a burst
  11. Swift-BAT Trigger 159578 is a possible burst
  12. GRB050805A: Rc optical observations
  13. GRB 051006: Swift/UVOT Upper Limits
  14. IBAS Alert 2675 : not a GRB
  15. GRB051008: optical candidate
  16. GRB 051008: - a high redshift high-luminosity burst?
  17. GRB 051008 - a low redshift low-luminosity burst?
  18. IBAS Alert 2673: not a real GRB
  19. GRB051011: bright nebulae near error box
  20. GRB051011: MASTER optical observation
  21. GRB051008: optical observation
  22. GRB051008: Swift XRT refined analysis
  23. GRB051008 - Swift UVOT upper limits
  24. Konus-Wind observation of GRB 051008
  25. GRB051008: Final refined analysis of the Swift-BAT burst
  26. GRB 051008: R-band upper limit
  27. GRB051008: Refined analysis of the Swift-BAT burst
  28. GRB051008: Radio Observation
  29. GRB 051008: Swift XRT position
  30. GRB 051008, optical observations
  31. GRB 051008: early Swift XRT analysis
  32. GRB 051008: Swift UVOT Candidate
  33. GRB051008: Swift-BAT detection of a bright burst
  34. GRB 051006: P60 Observations
  35. grb test
  36. GRB 051006: XRT refined analysis
  37. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  38. GRB 051006: optical observations at Sierra Nevada
  39. GRB051006: Refined analysis of the Swift-BAT burst
  40. GRB 051006: XRT position
  41. GRB051006: Swift detection of a burst
  42. GRB 050906, summary of radio observations
  43. Swift-BAT triggers 158261 and 158262 Retraction
  44. GRB051001: Swift UVOT Upper Limits
  45. GRB 050925: Second Epoch WSRT Radio Observations
  46. GRB 051001: Swift XRT refined analysis
  47. GRB 051001, optical observations at Mt. John
  48. GRB 051001: I-band limit
  49. GRB 051001: AAT infra-red observations
  50. GRB 051001: Swift-BAT refined analysis
  51. GRB 051001: Swift Detection of a Burst
  52. GRB 051001: ROTSE-III Optical Limits
  53. GRB050908: optical observations
  54. GRB050922C: optical observation
  55. GRB050922B: optical limit
  56. GRB 050922C: further VLT observations
  57. GRB 050820A: NIR photometry at the TNG
  58. GRB050922C: UVES/VLT high resolution spectroscopy
  59. GRB050925: Swift/XRT limits
  60. GRB/SGR 050925: IR Observations
  61. GRB050922C - Swift UVOT preliminary analysis
  62. GRB 050922C: break in the lightcurve
  63. GRB 050925: WSRT Radio Observations
  64. GRB050925: Swift UVOT upper limits
  65. Refined analysis of the Swift-BAT soft short burst
  66. GRB 050925 : I-band observation at Xinglong observatory
  67. GRB050925: Faulkes Telescope North R-band limit
  68. GRB050925: Swift-BAT detection of a short burst
  69. GRB 050922B: Correction to BAT refined analysis, longer burst
  70. GRB050922C: TNG spectroscopic observations
  71. GRB050922B: refined XRT analysis
  72. Konus-Wind observation of GRB 050922C
  73. GRB 050922C: Refined redshift
  74. GRB050922B: Swift UVOT early upper limits.
  75. GRB OT observation
  76. GRB050922C: observation at MonteBoo
  77. INT 2.5m limit for GRB050922B
  78. GRB 050922B: optical limit
  79. GRB050922C: Optical Observations
  80. GRB 050922C: Swift XRT refined analysis
  81. HETE Fregate observations of GRB 050922C
  82. GRB 050922C: Swift-BAT refined analysis
  83. GRB 050922B: Swift-BAT refined analysis
  84. GRB050922C: optical observations
  85. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  86. GRB 050922C: optical obserations
  87. GRB 050922C: NOT optical observations
  88. GRB 050922A: Analysis of Swift/XRT TOO observation
  89. GRB 050922C: Swift detection of a bright burst
  90. GRB 050922C: ROTSE-IIId Refined Analysis
  91. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  92. GRB 050922B: ROTSE-III Optical Limits
  93. GRB 050922B,optical observation
  94. GRB050922B: Swift-BAT detection of a weak long burst
  95. Possible GRB 050922 detected by INTEGRAL
  96. GRB050918: Possible Swift/XRT detected afterglow
  97. GRB050820B: analysis of the XMM-Newton observation
  98. GRB050916: Swift/UVOT Upper Limits
  99. GRB 050916: Swift-BAT refined analysis
  100. GRB 050918 - A long GRB detected by INTEGRAL

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