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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').
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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"

43601 results found.

  1. GRB 051109: PROMPT Detections
  2. GRB 051109: Rc and Ic observations
  3. GRB051109: Early Super-LOTIS Detection
  4. GRB 051109: Swift-BAT refined analysis
  5. GRB 051109a: IR Photometry and Astrometry
  6. GRB 051109a: MDM Observations
  7. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  8. GRB051109: Swift detection of a burst
  9. GRB 051109a: IR Detections
  10. GRB 051109: ROTSE-III Detection of Possible Counterpart
  11. GRB051105B: Swift/XRT upper limit
  12. GRB051105B: Swift/UVOT upper limit
  13. GRB051103: optical observations
  14. GRB 051103, optical observations
  15. GRB051103: MASTER: OT limit and host galaxy candidates
  16. GRB051028: Swift-XRT refined analysis
  17. GRB 051105a, observation from Naini Tal and OSN
  18. GRB 051105A, 2nd epoch optical observations
  19. GRB 051105a: MDM Observations
  20. GRB 051105A: TNG optical observations
  21. GRB051105A: Swift/UVOT Observations
  22. GRB 051105A, radio observations
  23. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  24. GRB 051105A, optical observations
  25. XRT observations of GRB 051105A
  26. GRB 051105: Swift-BAT improved refined analysis
  27. GRB 051105b: ART optical limits
  28. GRB051105B - A long GRB detected by INTEGRAL
  29. GRB 051105B (INTEGRAL 2701): Optical observation
  30. GRB 051105: Swift-BAT refined analysis
  31. GRB 051105: Swift detection of a short burst
  32. IBAS Alert 2700: Not a GRB
  33. GRB 051016B host spectroscopy and redshift
  34. GRB051016B: optical observation
  35. Recent GRB UBVRcIc field photometry
  36. Konus-Wind observation of GRB 051028
  37. GRB051028 SARA Observation
  38. GRB051028: optical observations
  39. GRB051028: Swift/UVOT upper limits
  40. GRB051028: confirmation of the afterglow
  41. GRB051028: WHT optical candidate
  42. GRB051028: Swift XRT Position
  43. GRB 051028 (=H3951): A GRB localized by HETE
  44. GRB051022: Swift XRT measurement of jet break
  45. SGR 1806-20: continued moderate activity seen with INTEGRAL
  46. GRB051021B: Swift/UVOT Upper limits
  47. GRB 051021, Optical Observations
  48. GRB 051022: XRT Refined Spectral and Temporal Analysis
  49. GRB 051022, refined optical astrometry
  50. Chandra Observations of GRB 051022
  51. GRB051012: Swift-XRT analysis
  52. GRB 051022 Chandra Observations scheduled
  53. GRB051021B: Swift XRT refined analysis
  54. GRB051021a: optical observations
  55. GRB 051022: WSRT Radio Detection
  56. GRB 051022, mm counterpart
  57. GRB051022: host galaxy redshift
  58. GRB 051022: Swift/UVOT Upper Limits
  59. GRB051022: Radio Counterpart
  60. GRB051022: IR observations
  61. GRB 051022: SOAR JKs Observations
  62. GRB051021A: Swift XRT refined analysis
  63. Konus-Wind observation of GRB 051022
  64. GRB051022: Optical Observations
  65. GRB 051022: Magellan NIR imaging
  66. GRB 051021: PROMPT RcIc Observations
  67. GRB051021b: Magellan IR Imaging
  68. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  69. GRB 051021: Correction
  70. GRB 051022, J & K-band observation
  71. GRB 051021, SMARTS optical/IR observations
  72. GRB051022: Swift XRT Position
  73. GRB 051021: P200 Ks Observations
  74. IPN triangulation of GRB051022 (=H3950)
  75. GRB 051021: MDM Upper Limit
  76. GRB 051022 (=H3950): SXC Flight Localization is Valid
  77. GRB 051021B: Refined analysis of the Swift-BAT burst
  78. GRB 051022: SSO40 Optical Observations
  79. GRB 051022A: ROTSE-III Optical Limits
  80. GRB051022 (=H3590), A GRB Detected By HETE
  81. GRB 051022: Optical observations
  82. GRB051021B: Swift XRT Position
  83. GRB 051021: SOAR NIR Observations
  84. GRB 051021B: Swift detection of a burst
  85. GRB051021: Swift XRT analysis
  86. GRB051021 (=H3947): Refined Analysis
  87. GRB 051021: Optical observations
  88. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  89. GRB 051021: Optical observations and candidate afterglow
  90. Swift-BAT trigger 160640 is not a real GRB
  91. GRB051021: A GRB Localized by HETE
  92. Swift-BAT trigger 160619 is not a GRB
  93. Swift-BAT triggered on a posible CR Shower or possible GRB
  94. GRB 050502b: Optical limit
  95. Afterglow candidate of GRB 051016B observed at Lulin
  96. GRB 051016b: Gemini Near IR Observations
  97. GRB 051016A: Swift/UVOT upper limits
  98. GRB 051016B: refined analysis of the Swift/XRT data
  99. GRB 051016B: Swift/UVOT detection
  100. GRB 051016B,optical observation

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