------------------------------------------------------------------------ richichi_II.tex A&A, Jul 2008, in press MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_79454_9387393.1216623235381" X-Google-Sender-Auth: 9cd020161b147cdf X-MailScanner-Information: Please contact the postmaster@aoc.nrao.edu for more information X-MailScanner-ID: m6L6rtVt012206 X-MailScanner: Found to be clean X-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=0.001, required 5, autolearn=disabled, HTML_MESSAGE 0.00) X-MailScanner-From: octavi.fors@gmail.com X-Spam-Status: No ------=_Part_79454_9387393.1216623235381 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline %astro-ph/0807.2650 \documentclass{aa} \usepackage{graphicx} \usepackage{longtable} \usepackage{txfonts} \begin{document} \title{Milliarcsecond angular resolution of reddened stellar sources in the vicinity of the Galactic Center. II. Additional observations \thanks{Based on observations made with ESO telescopes at Paranal Observatory} } \author{A. Richichi\inst{1} \and O. Fors\inst{2}\fnmsep\inst{3} \and E. Mason\inst{4} } \institute{ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei M\"unchen, Germany \email{arichich@eso.org } \and Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Mart\'{\i} i Franqu\'es 1, 08028 Barcelona, Spain \and Observatori Fabra, Cam\'{\i} de l'Observatori s/n, 08035 Barcelona, Spain \and European Southern Observatory, Santiago, Chile } \abstract % context heading (optional) % {} leave it empty if necessary { We present lunar occultation (LO) observations obtained in August 2006 with the recently demonstrated burst mode of the ISAAC instrument at the ESO VLT. The results presented here follow the previously reported observations carried out in March 2006 on a similar but unrelated set of sources. } % aims heading (mandatory) { Interstellar extinction in the inner regions of the galactic bulge amounts to tens of magnitudes at visual wavelengths. As a consequence, the majority of sources in that area are poorly studied and large numbers of potentially interesting sources such as late-type giants with circumstellar shells, stellar masers, infrared stars, remain excluded from the typical investigations which are carried out in less problematic regions. Also undetected are a large numbers of binaries. By observing LO events in this region, we gain the means to investigate at least a selected number of sources with an unprecedented combination of sensitivity and angular resolution. } % methods heading (mandatory) { The LO technique permits to achieve milliarcsecond resolution with a sensitivity of K$\approx$12\,mag at a very large telescope. We have used the opportunity of a favorable passage of the Moon over a crowded region in the general direction of the Galactic Center to observe 78 LO events of heavily reddened stellar sources. } % results heading (mandatory) {We have detected six new binary and one triple star, with typical projected separation of $\approx 0\farcs01$. We have also detected the compact circumstellar emission around one maser and one central star of a planetary nebula. Additionally we have measured the diameter and/or circumstellar shell of two carbon stars and other IR sources. } % conclusions heading (optional), leave it empty if necessary {We have used the upper limits on the size of about 60 unresolved or marginally resolved sources to establish the performance of the method. In agreement with our previous result, we conclude that lunar occultations in fast read-out mode on a detector subwindow at an 8\,m-class telescope can achieve an angular resolution close to $0\farcs001$ with a sensitivity K$\approx 12$\,mag. } \keywords{ Techniques: high angular resolution -- Astrometry -- Occultations -- Stars: binaries -- Stars: carbon -- Masers } ------=_Part_79454_9387393.1216623235381 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline
%astro-ph/0807.2650

\documentclass{aa} 
\usepackage{graphicx}
\usepackage{longtable}
\usepackage{txfonts}
\begin{document}
   \title{Milliarcsecond angular resolution of reddened stellar sources in the vicinity of the Galactic Center. II. Additional observations
\thanks{Based on observations made with ESO telescopes at Paranal Observatory}
}

\author{A. Richichi\inst{1}
             \and
             O. Fors\inst{2}\fnmsep\inst{3}
             \and
             E. Mason\inst{4}
}

\institute{
             European Southern Observatory,
Karl-Schwarzschild-Str. 2, 85748 Garching bei M\"unchen, Germany
             \email{arichich@eso.org}
         \and
             Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Mart\'{\i} i Franqu\'es 1, 08028 Barcelona, Spain
         \and
             Observatori Fabra, Cam\'{\i} de l'Observatori s/n, 08035
Barcelona, Spain
         \and
             European Southern Observatory, Santiago, Chile
}

\abstract
  % context heading (optional)
  % {} leave it empty if necessary 
{
We present lunar occultation (LO)
observations obtained in August 2006 with the recently
demonstrated burst mode of the ISAAC instrument at the
ESO VLT. The results presented here follow the
previously reported observations carried out in March 2006 on a similar but unrelated set of sources.
}
  % aims heading (mandatory)
{
Interstellar extinction in the inner regions of the
galactic bulge amounts to tens of magnitudes at visual
wavelengths. As a consequence, the majority of sources
in that area are poorly studied and large numbers of
potentially interesting sources such as late-type giants
with circumstellar shells, stellar masers, infrared stars,
remain excluded from the typical investigations
which are carried out in less problematic regions.
Also undetected are a large numbers of binaries.
By observing LO events in this region, we gain the means
to investigate at least a selected number of sources
with an unprecedented combination of sensitivity and
angular resolution.
}
  % methods heading (mandatory)
{
The LO technique permits to achieve milliarcsecond resolution
with a sensitivity of K$\approx$12\,mag at a very large telescope. We have used the opportunity of a favorable passage of the Moon over a crowded region in the general direction of the Galactic Center to observe 78 LO events of heavily reddened stellar sources.
}
  % results heading (mandatory)
{We have detected six new binary and one triple star, with typical
projected separation of $\approx 0\farcs01$. We have also detected the compact circumstellar emission around one maser and one central star of a planetary nebula. Additionally we have measured the diameter and/or circumstellar shell of two carbon stars and other IR sources.
}
  % conclusions heading (optional), leave it empty if necessary
{We have used the upper limits on the size of about 60 unresolved
or marginally resolved sources to establish the performance of the
method. In agreement with our previous result, we conclude that
lunar occultations in fast read-out mode on a detector subwindow
at an 8\,m-class telescope can achieve an angular resolution close
to $0\farcs001$ with a sensitivity K$\approx 12$\,mag.
}

\keywords{
Techniques: high angular resolution --
Astrometry --
Occultations --
Stars: binaries --
Stars: carbon --
Masers
}

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