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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"

36077 results found.

  1. GRB051021a: optical observations
  2. GRB 051022: WSRT Radio Detection
  3. GRB 051022, mm counterpart
  4. GRB051022: host galaxy redshift
  5. GRB 051022: Swift/UVOT Upper Limits
  6. GRB051022: Radio Counterpart
  7. GRB 051022: SOAR JKs Observations
  8. Konus-Wind observation of GRB 051022
  9. GRB051022: Optical Observations
  10. GRB 051022: Magellan NIR imaging
  11. GRB 051021: PROMPT RcIc Observations
  12. GRB051021b: Magellan IR Imaging
  13. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  14. GRB 051021: Correction
  15. GRB 051022, J & K-band observation
  16. GRB 051021, SMARTS optical/IR observations
  17. GRB 051021: P200 Ks Observations
  18. IPN triangulation of GRB051022 (=H3950)
  19. GRB 051021: MDM Upper Limit
  20. GRB 051022 (=H3950): SXC Flight Localization is Valid
  21. GRB051021: Swift/UVOT Upper Limits
  22. GRB 051021B: Refined analysis of the Swift-BAT burst
  23. GRB 051022: SSO40 Optical Observations
  24. GRB 051022A: ROTSE-III Optical Limits
  25. GRB051022 (=H3590), A GRB Detected By HETE
  26. GRB 051022: Optical observations
  27. GRB 051021,optical observation
  28. GRB051021B: Swift XRT Position
  29. GRB 051021: SOAR NIR Observations
  30. GRB 051021B: Swift detection of a burst
  31. GRB051021 (=H3947): Refined Analysis
  32. GRB 051021 : optical afterglow observation at Lulin
  33. GRB 051021: Optical observations
  34. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  35. GRB 051021: Optical observations and candidate afterglow
  36. GRB051021.63
  37. GRB051021.6: MASTER optical observation
  38. Swift-BAT trigger 160640 is not a real GRB
  39. GRB051021: A GRB Localized by HETE
  40. Swift-BAT trigger 160619 is not a GRB
  41. Swift-BAT triggered on a posible CR Shower or possible GRB
  42. GRB 050502b: Optical limit
  43. GRB 051016b: Optical limit
  44. Afterglow candidate of GRB 051016B observed at Lulin
  45. GRB 051016b: Gemini Near IR Observations
  46. GRB 051016A: Swift/UVOT upper limits
  47. GRB 051016B: refined analysis of the Swift/XRT data
  48. GRB 051016B: Swift/UVOT detection
  49. GRB 051016B,optical observation
  50. GRB 051016B : Optical follow-up at Lulin
  51. GRB 051016B: Refined analysis of the Swift-BAT burst
  52. GRB 051016B: Swift detection of a soft burst
  53. GRB 051016: Swift-BAT refined analysis
  54. GRB051016: Swift XRT refined analysis.
  55. GRB 051016: LCO optical and near-IR imaging
  56. GRB 051016: PROMPT Observations
  57. GRB051016: Swift detection of a burst
  58. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  59. GRB051006: optical observations
  60. GRB 051012: Swift-BAT detection of burst yesterday
  61. Swift trigger 159578 is not a burst
  62. GRB 051006: Swift/UVOT Upper Limits
  63. IBAS Alert 2675 : not a GRB
  64. GRB051008: optical candidate
  65. GRB 051008: - a high redshift high-luminosity burst?
  66. GRB 051008 - a low redshift low-luminosity burst?
  67. IBAS Alert 2673: not a real GRB
  68. GRB051011: MASTER optical observation
  69. GRB051008: optical observation
  70. GRB051008: Swift XRT refined analysis
  71. GRB051008 - Swift UVOT upper limits
  72. Konus-Wind observation of GRB 051008
  73. GRB051008: Final refined analysis of the Swift-BAT burst
  74. GRB 051008: R-band upper limit
  75. GRB051008: Radio Observation
  76. GRB 051008: Swift XRT position
  77. GRB 051008, optical observations
  78. GRB 051008: early Swift XRT analysis
  79. GRB 051008: Swift UVOT Candidate
  80. GRB 051006: P60 Observations
  81. grb test
  82. GRB 051006: XRT refined analysis
  83. GRB 051006: optical observations at Sierra Nevada
  84. GRB 051006: XRT position
  85. GRB 050906, summary of radio observations
  86. GRB 050925: Second Epoch WSRT Radio Observations
  87. GRB 051001: Swift XRT refined analysis
  88. GRB 051001, optical observations at Mt. John
  89. GRB 051001: I-band limit
  90. GRB 051001: AAT infra-red observations
  91. GRB 051001: Swift-BAT refined analysis
  92. GRB 051001: Swift Detection of a Burst
  93. GRB 051001: ROTSE-III Optical Limits
  94. GRB050908: optical observations
  95. GRB050922C: optical observation
  96. GRB050922B: optical limit
  97. GRB 050922C: further VLT observations
  98. GRB 050820A: NIR photometry at the TNG
  99. GRB050922C: UVES/VLT high resolution spectroscopy
  100. GRB050925: Swift/XRT limits

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