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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 051109: Rc and Ic observations
  2. GRB051109: Early Super-LOTIS Detection
  3. GRB 051109: Swift-BAT refined analysis
  4. GRB 051109a: IR Photometry and Astrometry
  5. GRB 051109a: MDM Observations
  6. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  7. GRB051109: Swift detection of a burst
  8. GRB 051109a: IR Detections
  9. GRB 051109: ROTSE-III Detection of Possible Counterpart
  10. GRB051105B: Swift/XRT upper limit
  11. GRB051105B: Swift/UVOT upper limit
  12. GRB051103: optical observations
  13. GRB 051103, optical observations
  14. GRB051103: MASTER: OT limit and host galaxy candidates
  15. GRB051028: Swift-XRT refined analysis
  16. GRB 051105a, observation from Naini Tal and OSN
  17. GRB 051105A, 2nd epoch optical observations
  18. GRB 051105a: MDM Observations
  19. GRB 051105A: TNG optical observations
  20. GRB051105A: Swift/UVOT Observations
  21. GRB 051105A, radio observations
  22. GRB051103:_MASTER_optical_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: Optical limit
  32. GRB 051105: Swift detection of a short burst
  33. IBAS Alert 2700: Not a GRB
  34. GRB 051016B host spectroscopy and redshift
  35. GRB051016B: optical observation
  36. Recent GRB UBVRcIc field photometry
  37. Konus-Wind observation of GRB 051028
  38. GRB051028:MASTER correction and final results
  39. GRB 051022: RTT150 optical observations
  40. GRB 051021A: RTT150 optical observations
  41. GRB051028 SARA Observation
  42. GRB051028: optical observations
  43. GRB051028: Swift/UVOT upper limits
  44. GRB051028: confirmation of the afterglow
  45. GRB051028: WHT optical candidate
  46. GRB051028: Swift XRT Position
  47. GRB051028:MASTER observations
  48. GRB 051028 (=H3951): A GRB localized by HETE
  49. GRB051028:MASTER optical observations
  50. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  51. GRB051022: Swift XRT measurement of jet break
  52. SGR 1806-20: continued moderate activity seen with INTEGRAL
  53. GRB051021B: Swift/UVOT Upper limits
  54. GRB 051021, Optical Observations
  55. GRB 051022: XRT Refined Spectral and Temporal Analysis
  56. GRB 051022, refined optical astrometry
  57. Chandra Observations of GRB 051022
  58. GRB051012: Swift-XRT analysis
  59. GRB 051022 Chandra Observations scheduled
  60. GRB051021B: Swift XRT refined analysis
  61. GRB051021a: optical observations
  62. GRB 051022: WSRT Radio Detection
  63. GRB 051022, mm counterpart
  64. GRB051022: host galaxy redshift
  65. GRB 051022: Swift/UVOT Upper Limits
  66. GRB051022: Radio Counterpart
  67. GRB051022: IR observations
  68. GRB 051022: SOAR JKs Observations
  69. GRB051021A: Swift XRT refined analysis
  70. Konus-Wind observation of GRB 051022
  71. GRB051022: Optical Observations
  72. GRB 051022: Magellan NIR imaging
  73. GRB 051021: PROMPT RcIc Observations
  74. GRB051021b: Magellan IR Imaging
  75. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  76. GRB 051021: Correction
  77. GRB 051022, J & K-band observation
  78. GRB 051021, SMARTS optical/IR observations
  79. GRB051022: Swift XRT Position
  80. GRB 051021: P200 Ks Observations
  81. IPN triangulation of GRB051022 (=H3950)
  82. GRB 051021: MDM Upper Limit
  83. GRB 051022 (=H3950): SXC Flight Localization is Valid
  84. GRB051021: Swift/UVOT Upper Limits
  85. GRB 051021B: Refined analysis of the Swift-BAT burst
  86. GRB 051022: SSO40 Optical Observations
  87. GRB051022,optical observation
  88. GRB 051022A: ROTSE-III Optical Limits
  89. GRB051022 (=H3590), A GRB Detected By HETE
  90. GRB 051022: Optical observations
  91. GRB 051021,optical observation
  92. GRB051021B: Swift XRT Position
  93. GRB 051021: SOAR NIR Observations
  94. GRB 051021B: Swift detection of a burst
  95. GRB051021: Swift XRT analysis
  96. GRB051021 (=H3947): Refined Analysis
  97. GRB 051021 : optical afterglow observation at Lulin
  98. GRB 051021: Optical observations
  99. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  100. GRB 051021: Optical observations and candidate afterglow

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