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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"

37513 results found.

  1. GRB 051016B : Optical follow-up at Lulin
  2. GRB 051016B: Refined analysis of the Swift-BAT burst
  3. GRB 051016B: Swift detection of a soft burst
  4. GRB 051016: Swift-BAT refined analysis
  5. GRB051016: Swift XRT refined analysis.
  6. GRB 051016: LCO optical and near-IR imaging
  7. GRB 051016: PROMPT Observations
  8. GRB051016: Swift detection of a burst
  9. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  10. GRB051006: optical observations
  11. GRB 051012: Swift-BAT detection of burst yesterday
  12. Swift trigger 159578 is not a burst
  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: 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: Radio Observation
  27. GRB 051008: Swift XRT position
  28. GRB 051008, optical observations
  29. GRB 051008: early Swift XRT analysis
  30. GRB 051008: Swift UVOT Candidate
  31. GRB 051006: P60 Observations
  32. grb test
  33. GRB 051006: XRT refined analysis
  34. GRB 051006: optical observations at Sierra Nevada
  35. GRB 051006: XRT position
  36. GRB 050906, summary of radio observations
  37. GRB 050925: Second Epoch WSRT Radio Observations
  38. GRB 051001: Swift XRT refined analysis
  39. GRB 051001, optical observations at Mt. John
  40. GRB 051001: I-band limit
  41. GRB 051001: AAT infra-red observations
  42. GRB 051001: Swift-BAT refined analysis
  43. GRB 051001: Swift Detection of a Burst
  44. GRB 051001: ROTSE-III Optical Limits
  45. GRB050908: optical observations
  46. GRB050922C: optical observation
  47. GRB050922B: optical limit
  48. GRB 050922C: further VLT observations
  49. GRB 050820A: NIR photometry at the TNG
  50. GRB050922C: UVES/VLT high resolution spectroscopy
  51. GRB050925: Swift/XRT limits
  52. GRB/SGR 050925: IR Observations
  53. GRB 050922C: break in the lightcurve
  54. GRB 050925: WSRT Radio Observations
  55. GRB 050925 : I-band observation at Xinglong observatory
  56. GRB050925: Faulkes Telescope North R-band limit
  57. GRB050925: Swift-BAT detection of a short burst
  58. GRB 050922B: Correction to BAT refined analysis, longer burst
  59. GRB050922C: TNG spectroscopic observations
  60. GRB050922B: refined XRT analysis
  61. Konus-Wind observation of GRB 050922C
  62. GRB 050922C: Refined redshift
  63. GRB OT observation
  64. GRB050922C: observation at MonteBoo
  65. INT 2.5m limit for GRB050922B
  66. GRB 050922B: optical limit
  67. GRB050922C: Optical Observations
  68. GRB 050922C: Swift XRT refined analysis
  69. HETE Fregate observations of GRB 050922C
  70. GRB 050922C: Swift-BAT refined analysis
  71. GRB 050922B: Swift-BAT refined analysis
  72. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  73. GRB 050922C: optical obserations
  74. GRB 050922C: NOT optical observations
  75. GRB 050922A: Analysis of Swift/XRT TOO observation
  76. GRB 050922C: Swift detection of a bright burst
  77. GRB 050922C: ROTSE-IIId Refined Analysis
  78. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  79. GRB 050922B: ROTSE-III Optical Limits
  80. GRB 050922B,optical observation
  81. GRB050922B: Swift-BAT detection of a weak long burst
  82. Possible GRB 050922 detected by INTEGRAL
  83. GRB050820B: analysis of the XMM-Newton observation
  84. GRB050916: Swift/UVOT Upper Limits
  85. GRB 050916: Swift-BAT refined analysis
  86. GRB 050918 - A long GRB detected by INTEGRAL
  87. GRB 050915a: Radio Observations
  88. Swift-BAT trigger 155764 is not a GRB
  89. Swift-BAT trigger 155764 is probably not a GRB
  90. Swift-BAT trigger 155535 is definitely not a GRB
  91. GRB 050916: XRT position
  92. GRB 050915b, SMARTS optical/IR observations of the XRT position
  93. GRB 050915B: Swift-BAT refined analysis
  94. GRB 050915B: Swift/UVOT Upper Limits
  95. GRB 050915a: IR Transient
  96. GRB 050915B: XRT position
  97. GRB 050915b, SMARTS optical/IR observations
  98. GRB 050915: KAIT optical limit
  99. GRB 050915: IR Observations
  100. GRB 050915: Swift XRT refined analysis

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