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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. GRB051111: Swift/UVOT Observations
  2. GRB 051111A : R-band temporal decay index based on Lulin
  3. GRB051111: XRT preliminary analysis
  4. GRB 051111: Swift-BAT refined analysis
  5. GRB 051109A Optical Observations
  6. GRB 051111A : Lulin BVRI multi band afterglow observation
  7. GRB051111a: SARA Observations
  8. GRB 051111a: IR photometry
  9. GRB 051111: Keck HIRES redshift
  10. GRB 051111A: KAIT optical observations
  11. GRB 051111a: Afterglow fading in Ic
  12. GRB051111: Super-LOTIS Early Detection
  13. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  14. Faulkes Telescope R-band detection of GRB051111
  15. GRB 051103 Milagro GeV/TeV Observations
  16. GRB051111: Swift-BAT detection of a bright burst
  17. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  18. GRB 051008 Tautenburg Supernova Search
  19. GRB 051109B. Radio Observations
  20. GRB 051109A
  21. GRB051109A - radio observations
  22. GRB 051105a: GETS optical limit
  23. GRB 051109b: GETS observation
  24. GRB 051109A: KAIT optical observations
  25. Early RAPTOR measurements of GRB 051109a - the movie.
  26. Konus-Wind observation of GRB 051109A
  27. GRB 051109B: Swift-BAT refined analysis
  28. GRB 051109B: ROTSE-III Optical Limits
  29. GRB 051109A: Swift-UVOT Observations
  30. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  31. GRB051109B: no UVOT source detected
  32. GRB051109B: XRT refined analysis
  33. GRB 051109B : Lulin Optical Observations
  34. GRB 051109A : Lulin BVRI Optical afterglow observation
  35. GRB051109A: further steepening in the X-ray light curve
  36. GRB051109A: XRT refined analysis
  37. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  38. GRB051109B: XRT position
  39. GRB 051109B: Super-LOTIS Observations
  40. GRB 051109B Kiso optical follow-up observation
  41. GRB051105B: REM Optical observation
  42. GRB 051109B: Swift detection of a burst
  43. GRB 051109: HET Optical Spectrum and Absorption Redshift
  44. GRB 051109: PROMPT Detections
  45. GRB 051109: Rc and Ic observations
  46. GRB051109: Early Super-LOTIS Detection
  47. GRB 051109: Swift-BAT refined analysis
  48. GRB 051109a: IR Photometry and Astrometry
  49. GRB 051109a: MDM Observations
  50. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  51. GRB051109: Swift detection of a burst
  52. GRB 051109a: IR Detections
  53. GRB 051109: ROTSE-III Detection of Possible Counterpart
  54. GRB051105B: Swift/XRT upper limit
  55. GRB051105B: Swift/UVOT upper limit
  56. GRB051103: optical observations
  57. GRB 051103, optical observations
  58. GRB051103: MASTER: OT limit and host galaxy candidates
  59. GRB051028: Swift-XRT refined analysis
  60. GRB 051105a, observation from Naini Tal and OSN
  61. GRB 051105A, 2nd epoch optical observations
  62. GRB 051105a: MDM Observations
  63. GRB 051105A: TNG optical observations
  64. GRB051105A: Swift/UVOT Observations
  65. GRB 051105A, radio observations
  66. GRB051103:_MASTER_optical_observations
  67. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  68. GRB 051105A, optical observations
  69. XRT observations of GRB 051105A
  70. GRB 051105: Swift-BAT improved refined analysis
  71. GRB 051105b: ART optical limits
  72. GRB051105B - A long GRB detected by INTEGRAL
  73. GRB 051105B (INTEGRAL 2701): Optical observation
  74. GRB 051105: Swift-BAT refined analysis
  75. GRB 051105: Optical limit
  76. GRB 051105: Swift detection of a short burst
  77. IBAS Alert 2700: Not a GRB
  78. GRB 051016B host spectroscopy and redshift
  79. GRB051016B: optical observation
  80. Recent GRB UBVRcIc field photometry
  81. Konus-Wind observation of GRB 051028
  82. GRB051028:MASTER correction and final results
  83. GRB 051022: RTT150 optical observations
  84. GRB 051021A: RTT150 optical observations
  85. GRB051028 SARA Observation
  86. GRB051028: optical observations
  87. GRB051028: Swift/UVOT upper limits
  88. GRB051028: confirmation of the afterglow
  89. GRB051028: WHT optical candidate
  90. GRB051028: Swift XRT Position
  91. GRB051028:MASTER observations
  92. GRB 051028 (=H3951): A GRB localized by HETE
  93. GRB051028:MASTER optical observations
  94. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  95. GRB051022: Swift XRT measurement of jet break
  96. SGR 1806-20: continued moderate activity seen with INTEGRAL
  97. GRB051021B: Swift/UVOT Upper limits
  98. GRB 051021, Optical Observations
  99. GRB 051022: XRT Refined Spectral and Temporal Analysis
  100. GRB 051022, refined optical astrometry

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