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

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