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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. GRB051103: Radio Observations
  2. GRB 051109A Milagro GeV/TeV Observations
  3. GRB/SGR 050925: XMM-Newton ToO observation
  4. GRB051111: Swift/UVOT Observations
  5. GRB 051111A : R-band temporal decay index based on Lulin
  6. GRB051111: XRT preliminary analysis
  7. GRB 051111: Swift-BAT refined analysis
  8. GRB 051109A Optical Observations
  9. GRB 051111A : Lulin BVRI multi band afterglow observation
  10. GRB051111a: SARA Observations
  11. GRB 051111a: IR photometry
  12. GRB 051111: Keck HIRES redshift
  13. GRB 051111A: KAIT optical observations
  14. GRB 051111a: Afterglow fading in Ic
  15. GRB051111: Super-LOTIS Early Detection
  16. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  17. Faulkes Telescope R-band detection of GRB051111
  18. GRB 051103 Milagro GeV/TeV Observations
  19. GRB051111: Swift-BAT detection of a bright burst
  20. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  21. GRB 051008 Tautenburg Supernova Search
  22. GRB 051109B. Radio Observations
  23. GRB 051109A
  24. GRB051109A - radio observations
  25. GRB 051105a: GETS optical limit
  26. GRB 051109b: GETS observation
  27. GRB 051109A: KAIT optical observations
  28. Early RAPTOR measurements of GRB 051109a - the movie.
  29. Konus-Wind observation of GRB 051109A
  30. GRB 051109B: Swift-BAT refined analysis
  31. GRB 051109B: ROTSE-III Optical Limits
  32. GRB 051109A: Swift-UVOT Observations
  33. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  34. GRB051109B: no UVOT source detected
  35. GRB051109B: XRT refined analysis
  36. GRB 051109B : Lulin Optical Observations
  37. GRB 051109A : Lulin BVRI Optical afterglow observation
  38. GRB051109A: further steepening in the X-ray light curve
  39. GRB051109A: XRT refined analysis
  40. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  41. GRB051109B: XRT position
  42. GRB 051109B: Super-LOTIS Observations
  43. GRB 051109B Kiso optical follow-up observation
  44. GRB051105B: REM Optical observation
  45. GRB 051109B: Swift detection of a burst
  46. GRB 051109: HET Optical Spectrum and Absorption Redshift
  47. GRB 051109: PROMPT Detections
  48. GRB 051109: Rc and Ic observations
  49. GRB051109: Early Super-LOTIS Detection
  50. GRB 051109: Swift-BAT refined analysis
  51. GRB 051109a: IR Photometry and Astrometry
  52. GRB 051109a: MDM Observations
  53. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  54. GRB051109: Swift detection of a burst
  55. GRB 051109a: IR Detections
  56. GRB 051109: ROTSE-III Detection of Possible Counterpart
  57. GRB051105B: Swift/XRT upper limit
  58. GRB051105B: Swift/UVOT upper limit
  59. GRB051103: optical observations
  60. GRB 051103, optical observations
  61. GRB051103: MASTER: OT limit and host galaxy candidates
  62. GRB051028: Swift-XRT refined analysis
  63. GRB 051105a, observation from Naini Tal and OSN
  64. GRB 051105A, 2nd epoch optical observations
  65. GRB 051105a: MDM Observations
  66. GRB 051105A: TNG optical observations
  67. GRB051105A: Swift/UVOT Observations
  68. GRB 051105A, radio observations
  69. GRB051103:_MASTER_optical_observations
  70. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  71. GRB 051105A, optical observations
  72. XRT observations of GRB 051105A
  73. GRB 051105: Swift-BAT improved refined analysis
  74. GRB 051105b: ART optical limits
  75. GRB051105B - A long GRB detected by INTEGRAL
  76. GRB 051105B (INTEGRAL 2701): Optical observation
  77. GRB 051105: Swift-BAT refined analysis
  78. GRB 051105: Optical limit
  79. GRB 051105: Swift detection of a short burst
  80. IBAS Alert 2700: Not a GRB
  81. GRB 051016B host spectroscopy and redshift
  82. GRB051016B: optical observation
  83. Recent GRB UBVRcIc field photometry
  84. Konus-Wind observation of GRB 051028
  85. GRB051028:MASTER correction and final results
  86. GRB 051022: RTT150 optical observations
  87. GRB 051021A: RTT150 optical observations
  88. GRB051028 SARA Observation
  89. GRB051028: optical observations
  90. GRB051028: Swift/UVOT upper limits
  91. GRB051028: confirmation of the afterglow
  92. GRB051028: WHT optical candidate
  93. GRB051028: Swift XRT Position
  94. GRB051028:MASTER observations
  95. GRB 051028 (=H3951): A GRB localized by HETE
  96. GRB051028:MASTER optical observations
  97. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  98. GRB051022: Swift XRT measurement of jet break
  99. SGR 1806-20: continued moderate activity seen with INTEGRAL
  100. GRB051021B: Swift/UVOT Upper limits

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