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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: Swift XRT refined analysis.
  2. GRB051016: Planned XMM-Newton observation
  3. GRB 051016: LCO optical and near-IR imaging
  4. GRB 051016: PROMPT Observations
  5. GRB051016: Swift detection of a burst
  6. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  7. GRB051006: optical observations
  8. GRB 051012: Swift-BAT detection of burst yesterday
  9. Swift trigger 159578 is not a burst
  10. Swift-BAT Trigger 159578 is a possible burst
  11. GRB050805A: Rc optical observations
  12. GRB 051006: Swift/UVOT Upper Limits
  13. IBAS Alert 2675 : not a GRB
  14. GRB051008: optical candidate
  15. GRB 051008: - a high redshift high-luminosity burst?
  16. GRB 051008 - a low redshift low-luminosity burst?
  17. IBAS Alert 2673: not a real GRB
  18. GRB051011: bright nebulae near error box
  19. GRB051011: MASTER optical observation
  20. GRB051008: optical observation
  21. GRB051008: Swift XRT refined analysis
  22. GRB051008 - Swift UVOT upper limits
  23. Konus-Wind observation of GRB 051008
  24. GRB051008: Final refined analysis of the Swift-BAT burst
  25. GRB 051008: R-band upper limit
  26. GRB051008: Refined analysis of the Swift-BAT burst
  27. GRB051008: Radio Observation
  28. GRB 051008: Swift XRT position
  29. GRB 051008, optical observations
  30. GRB 051008: early Swift XRT analysis
  31. GRB 051008: Swift UVOT Candidate
  32. GRB051008: Swift-BAT detection of a bright burst
  33. GRB 051006: P60 Observations
  34. grb test
  35. GRB 051006: XRT refined analysis
  36. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  37. GRB 051006: optical observations at Sierra Nevada
  38. GRB051006: Refined analysis of the Swift-BAT burst
  39. GRB 051006: XRT position
  40. GRB051006: Swift detection of a burst
  41. GRB 050906, summary of radio observations
  42. Swift-BAT triggers 158261 and 158262 Retraction
  43. GRB051001: Swift UVOT Upper Limits
  44. GRB 050925: Second Epoch WSRT Radio Observations
  45. GRB 051001: Swift XRT refined analysis
  46. GRB 051001, optical observations at Mt. John
  47. GRB 051001: I-band limit
  48. GRB 051001: AAT infra-red observations
  49. GRB 051001: Swift-BAT refined analysis
  50. GRB 051001: Swift Detection of a Burst
  51. GRB 051001: ROTSE-III Optical Limits
  52. GRB050908: optical observations
  53. GRB050922C: optical observation
  54. GRB050922B: optical limit
  55. GRB 050922C: further VLT observations
  56. GRB 050820A: NIR photometry at the TNG
  57. GRB050922C: UVES/VLT high resolution spectroscopy
  58. GRB050925: Swift/XRT limits
  59. GRB/SGR 050925: IR Observations
  60. GRB050922C - Swift UVOT preliminary analysis
  61. GRB 050922C: break in the lightcurve
  62. GRB 050925: WSRT Radio Observations
  63. GRB050925: Swift UVOT upper limits
  64. Refined analysis of the Swift-BAT soft short burst
  65. GRB 050925 : I-band observation at Xinglong observatory
  66. GRB050925: Faulkes Telescope North R-band limit
  67. GRB050925: Swift-BAT detection of a short burst
  68. GRB 050922B: Correction to BAT refined analysis, longer burst
  69. GRB050922C: TNG spectroscopic observations
  70. GRB050922B: refined XRT analysis
  71. Konus-Wind observation of GRB 050922C
  72. GRB 050922C: Refined redshift
  73. GRB050922B: Swift UVOT early upper limits.
  74. GRB OT observation
  75. GRB050922C: observation at MonteBoo
  76. INT 2.5m limit for GRB050922B
  77. GRB 050922B: optical limit
  78. GRB050922C: Optical Observations
  79. GRB 050922C: Swift XRT refined analysis
  80. HETE Fregate observations of GRB 050922C
  81. GRB 050922C: Swift-BAT refined analysis
  82. GRB 050922B: Swift-BAT refined analysis
  83. GRB050922C: optical observations
  84. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  85. GRB 050922C: optical obserations
  86. GRB 050922C: NOT optical observations
  87. GRB 050922A: Analysis of Swift/XRT TOO observation
  88. GRB 050922C: Swift detection of a bright burst
  89. GRB 050922C: ROTSE-IIId Refined Analysis
  90. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  91. GRB 050922B: ROTSE-III Optical Limits
  92. GRB 050922B,optical observation
  93. GRB050922B: Swift-BAT detection of a weak long burst
  94. Possible GRB 050922 detected by INTEGRAL
  95. GRB050918: Possible Swift/XRT detected afterglow
  96. GRB050820B: analysis of the XMM-Newton observation
  97. GRB050916: Swift/UVOT Upper Limits
  98. GRB 050916: Swift-BAT refined analysis
  99. GRB 050918 - A long GRB detected by INTEGRAL
  100. GRB 050915a: Radio Observations

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