Bibcode
Labadie, L.; Rebolo, R.; Femenía, B.; Villó, Isidro; Díaz-Sánchez, Anastasio; Oscoz, A.; López, R.; Pérez-Prieto, J. A.; Pérez-Garrido, Antonio; Hildebrandt, Sergi R.; Béjar, V. J. S.; José Piqueras, Juan; Rodríguez, L. F.
Referencia bibliográfica
Ground-based and Airborne Instrumentation for Astronomy III. Edited by McLean, Ian S.; Ramsay, Suzanne K.; Takami, Hideki. Proceedings of the SPIE, Volume 7735, pp. 77350X-77350X-11 (2010).
Advertised on:
7
2010
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Descripción
In this paper, we present an original observational approach, which
combines, for the first time, traditional speckle imaging with image
post-processing to obtain in the optical domain diffraction-limited
images with high contrast (10-5) within 0.5 to 2 arcseconds
around a bright star. The post-processing step is based on wavelet
filtering an has analogy with edge enhancement and high-pass filtering.
Our I-band on-sky results with the 2.5-m Nordic Telescope (NOT) and the
lucky imaging instrument FASTCAM show that we are able to detect L-type
brown dwarf companions around a solar-type star with a contrast
▵I~12 at 2 and with no use of any coronographic capability, which
greatly simplifies the instrumental and hardware approach. This object
has been detected from the ground in J and H bands so far only with
AO-assisted 8-10 m class telescopes (Gemini, Keck), although more
recently detected with small-class telescopes in the K band. Discussing
the advantage and disadvantage of the optical regime for the detection
of faint intrinsic fluxes close to bright stars, we develop some
perspectives for other fields, including the study of dense cores in
globular clusters. To the best of our knowledge this is the first time
that high contrast considerations are included in optical speckle
imaging approach.