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

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