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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 051111A : Lulin BVRI multi band afterglow observation
  2. GRB051111a: SARA Observations
  3. GRB 051111a: IR photometry
  4. GRB 051111: Keck HIRES redshift
  5. GRB 051111A: KAIT optical observations
  6. GRB 051111a: Afterglow fading in Ic
  7. GRB051111: Super-LOTIS Early Detection
  8. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  9. Faulkes Telescope R-band detection of GRB051111
  10. GRB 051103 Milagro GeV/TeV Observations
  11. GRB051111: Swift-BAT detection of a bright burst
  12. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  13. GRB 051008 Tautenburg Supernova Search
  14. GRB 051109B. Radio Observations
  15. GRB 051109A
  16. GRB051109A - radio observations
  17. GRB 051105a: GETS optical limit
  18. GRB 051109b: GETS observation
  19. GRB 051109A: KAIT optical observations
  20. Early RAPTOR measurements of GRB 051109a - the movie.
  21. Konus-Wind observation of GRB 051109A
  22. GRB 051109B: Swift-BAT refined analysis
  23. GRB 051109B: ROTSE-III Optical Limits
  24. GRB 051109A: Swift-UVOT Observations
  25. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  26. GRB051109B: no UVOT source detected
  27. GRB051109B: XRT refined analysis
  28. GRB 051109B : Lulin Optical Observations
  29. GRB 051109A : Lulin BVRI Optical afterglow observation
  30. GRB051109A: further steepening in the X-ray light curve
  31. GRB051109A: XRT refined analysis
  32. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  33. GRB051109B: XRT position
  34. GRB 051109B: Super-LOTIS Observations
  35. GRB 051109B Kiso optical follow-up observation
  36. GRB051105B: REM Optical observation
  37. GRB 051109B: Swift detection of a burst
  38. GRB 051109: HET Optical Spectrum and Absorption Redshift
  39. GRB 051109: PROMPT Detections
  40. GRB 051109: Rc and Ic observations
  41. GRB051109: Early Super-LOTIS Detection
  42. GRB 051109: Swift-BAT refined analysis
  43. GRB 051109a: IR Photometry and Astrometry
  44. GRB 051109a: MDM Observations
  45. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  46. GRB051109: Swift detection of a burst
  47. GRB 051109a: IR Detections
  48. GRB 051109: ROTSE-III Detection of Possible Counterpart
  49. GRB051105B: Swift/XRT upper limit
  50. GRB051105B: Swift/UVOT upper limit
  51. GRB051103: optical observations
  52. GRB 051103, optical observations
  53. GRB051103: MASTER: OT limit and host galaxy candidates
  54. GRB051028: Swift-XRT refined analysis
  55. GRB 051105a, observation from Naini Tal and OSN
  56. GRB 051105A, 2nd epoch optical observations
  57. GRB 051105a: MDM Observations
  58. GRB 051105A: TNG optical observations
  59. GRB051105A: Swift/UVOT Observations
  60. GRB 051105A, radio observations
  61. GRB051103:_MASTER_optical_observations
  62. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  63. GRB 051105A, optical observations
  64. XRT observations of GRB 051105A
  65. GRB 051105: Swift-BAT improved refined analysis
  66. GRB 051105b: ART optical limits
  67. GRB051105B - A long GRB detected by INTEGRAL
  68. GRB 051105B (INTEGRAL 2701): Optical observation
  69. GRB 051105: Swift-BAT refined analysis
  70. GRB 051105: Optical limit
  71. GRB 051105: Swift detection of a short burst
  72. IBAS Alert 2700: Not a GRB
  73. GRB 051016B host spectroscopy and redshift
  74. GRB051016B: optical observation
  75. Recent GRB UBVRcIc field photometry
  76. Konus-Wind observation of GRB 051028
  77. GRB051028:MASTER correction and final results
  78. GRB 051022: RTT150 optical observations
  79. GRB 051021A: RTT150 optical observations
  80. GRB051028 SARA Observation
  81. GRB051028: optical observations
  82. GRB051028: Swift/UVOT upper limits
  83. GRB051028: confirmation of the afterglow
  84. GRB051028: WHT optical candidate
  85. GRB051028: Swift XRT Position
  86. GRB051028:MASTER observations
  87. GRB 051028 (=H3951): A GRB localized by HETE
  88. GRB051028:MASTER optical observations
  89. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  90. GRB051022: Swift XRT measurement of jet break
  91. SGR 1806-20: continued moderate activity seen with INTEGRAL
  92. GRB051021B: Swift/UVOT Upper limits
  93. GRB 051021, Optical Observations
  94. GRB 051022: XRT Refined Spectral and Temporal Analysis
  95. GRB 051022, refined optical astrometry
  96. Chandra Observations of GRB 051022
  97. GRB051012: Swift-XRT analysis
  98. GRB 051022 Chandra Observations scheduled
  99. GRB051021B: Swift XRT refined analysis
  100. GRB051021a: optical observations

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