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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. GRB051109A: XRT refined analysis
  2. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  3. GRB051109B: XRT position
  4. GRB 051109B: Super-LOTIS Observations
  5. GRB 051109B Kiso optical follow-up observation
  6. GRB051105B: REM Optical observation
  7. GRB 051109B: Swift detection of a burst
  8. GRB 051109: HET Optical Spectrum and Absorption Redshift
  9. GRB 051109: PROMPT Detections
  10. GRB 051109: Rc and Ic observations
  11. GRB051109: Early Super-LOTIS Detection
  12. GRB 051109: Swift-BAT refined analysis
  13. GRB 051109a: IR Photometry and Astrometry
  14. GRB 051109a: MDM Observations
  15. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  16. GRB051109: Swift detection of a burst
  17. GRB 051109a: IR Detections
  18. GRB 051109: ROTSE-III Detection of Possible Counterpart
  19. GRB051105B: Swift/XRT upper limit
  20. GRB051105B: Swift/UVOT upper limit
  21. GRB051103: optical observations
  22. GRB 051103, optical observations
  23. GRB051103: MASTER: OT limit and host galaxy candidates
  24. GRB051028: Swift-XRT refined analysis
  25. GRB 051105a, observation from Naini Tal and OSN
  26. GRB 051105A, 2nd epoch optical observations
  27. GRB 051105a: MDM Observations
  28. GRB 051105A: TNG optical observations
  29. GRB051105A: Swift/UVOT Observations
  30. GRB 051105A, radio observations
  31. GRB051103:_MASTER_optical_observations
  32. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  33. GRB 051105A, optical observations
  34. XRT observations of GRB 051105A
  35. GRB 051105: Swift-BAT improved refined analysis
  36. GRB 051105b: ART optical limits
  37. GRB051105B - A long GRB detected by INTEGRAL
  38. GRB 051105B (INTEGRAL 2701): Optical observation
  39. GRB 051105: Swift-BAT refined analysis
  40. GRB 051105: Optical limit
  41. GRB 051105: Swift detection of a short burst
  42. IBAS Alert 2700: Not a GRB
  43. GRB 051016B host spectroscopy and redshift
  44. GRB051016B: optical observation
  45. Recent GRB UBVRcIc field photometry
  46. Konus-Wind observation of GRB 051028
  47. GRB051028:MASTER correction and final results
  48. GRB 051022: RTT150 optical observations
  49. GRB 051021A: RTT150 optical observations
  50. GRB051028 SARA Observation
  51. GRB051028: optical observations
  52. GRB051028: Swift/UVOT upper limits
  53. GRB051028: confirmation of the afterglow
  54. GRB051028: WHT optical candidate
  55. GRB051028: Swift XRT Position
  56. GRB051028:MASTER observations
  57. GRB 051028 (=H3951): A GRB localized by HETE
  58. GRB051028:MASTER optical observations
  59. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  60. GRB051022: Swift XRT measurement of jet break
  61. SGR 1806-20: continued moderate activity seen with INTEGRAL
  62. GRB051021B: Swift/UVOT Upper limits
  63. GRB 051021, Optical Observations
  64. GRB 051022: XRT Refined Spectral and Temporal Analysis
  65. GRB 051022, refined optical astrometry
  66. Chandra Observations of GRB 051022
  67. GRB051012: Swift-XRT analysis
  68. GRB 051022 Chandra Observations scheduled
  69. GRB051021B: Swift XRT refined analysis
  70. GRB051021a: optical observations
  71. GRB 051022: WSRT Radio Detection
  72. GRB 051022, mm counterpart
  73. GRB051022: host galaxy redshift
  74. GRB 051022: Swift/UVOT Upper Limits
  75. GRB051022: Radio Counterpart
  76. GRB051022: IR observations
  77. GRB 051022: SOAR JKs Observations
  78. GRB051021A: Swift XRT refined analysis
  79. Konus-Wind observation of GRB 051022
  80. GRB051022: Optical Observations
  81. GRB 051022: Magellan NIR imaging
  82. GRB 051021: PROMPT RcIc Observations
  83. GRB051021b: Magellan IR Imaging
  84. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  85. GRB 051021: Correction
  86. GRB 051022, J & K-band observation
  87. GRB 051021, SMARTS optical/IR observations
  88. GRB051022: Swift XRT Position
  89. GRB 051021: P200 Ks Observations
  90. IPN triangulation of GRB051022 (=H3950)
  91. GRB 051021: MDM Upper Limit
  92. GRB 051022 (=H3950): SXC Flight Localization is Valid
  93. GRB051021: Swift/UVOT Upper Limits
  94. GRB 051021B: Refined analysis of the Swift-BAT burst
  95. GRB 051022: SSO40 Optical Observations
  96. GRB051022,optical observation
  97. GRB 051022A: ROTSE-III Optical Limits
  98. GRB051022 (=H3590), A GRB Detected By HETE
  99. GRB 051022: Optical observations
  100. GRB 051021,optical observation

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