A Breakthrough in Planetary Nebulae Research
Toshiya Ueta
% and the start of your text. \begin{abstract} % Leave intact We present the preliminary results from our {\sl HST}/NICMOS imaging polarimetry on optically thin PPNs. The data show the dust distribution in an unprecedented detail. The structure of these faint PPNs is revealed via polarization properties of the dust-scattered light without much interference from the bright central star, proving the unique advantages of the technique over simple imaging.
ueta2.tex
%APN3_PROCEEDINGS_FORM%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% SAMPLE1.TEX -- APN3 (2003) ASP Conference Proceedings sample
% paper with minimal markup. Based on the sample from ADASS XII (02).
%
% This is a simple example.  If you want to see a more comprehensive
% sample paper,  take a look at sample2.tex.
%
% Much of the input will be enclosed by braces (i.e., { }).  The
% percent sign, "%", denotes the start of a comment; text after it
% will be ignored by LaTeX.  You might also notice in some of the
% examples below the use of "\ " after a period; this prevents LaTeX
% from interpreting the period as the end of a sentence and putting
% extra space after it.   
% 
% You should check your paper by processing it with LaTeX.  For
% details about how to run LaTeX as well as how to print out the User
% Guide, consult the README file.  
%
% If you do not have access to the LaTeX software or a laser printer
% at your site, you can still prepare your paper following the
% instructions in the User Guide.  In such cases, the editors will
% process the file and make any necessary editorial adjustments.
% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
\documentclass[11pt,twoside]{article}  % Leave intact
\usepackage{apn3conf}

% If you have the old LaTeX 2.09, and not the current LaTeX2e, comment
% out the \documentclass and \usepackage lines above and uncomment
% the following:

%\documentstyle[11pt,twoside,apn3conf]{article}

\begin{document}   % Leave intact


%-----------------------------------------------------------------------
%		            Paper Title 
%-----------------------------------------------------------------------
% Enter the title of the paper.
%
% EXAMPLE: \title{A Breakthrough in Planetary Nebulae Research}
%
% If your title is so long as to fill the page header when you print it,
% then please supply a short form as a \titlemark.
%
% EXAMPLE:
%  \title{Magnetic Fields in the Shaping of Planetary Nebulae:
%         Observations Meet Theory}
%  \titlemark{Magnetic Fields in Planetary Nebulae}
%

\title{HST/NICMOS Imaging Polarimetry of PPNs}
%\titlemark{ }

%-----------------------------------------------------------------------
%		          Authors of Paper
%-----------------------------------------------------------------------
% Enter the authors followed by their affiliations.  The \author and
% \affil commands may appear multiple times as necessary.  List each
% author by giving the first name or initials first followed by the
% last name.  Authors with the same affiliations should grouped
% together. 
%
% Try to limit the front matter to no more than three \author
% commands.  Group authors with the same affiliations.  Too many
% \author commands fills the first page of the paper with little
% actual text.

\author{Toshiya Ueta}
\affil{Royal Observatory of Belgium, Ringlaan 3, B-1180, Belgium}
\author{Koji Murakawa}
\affil{Subaru Telescope, 650 N. A'ohoku Place, Hilo, HI 96720, USA}
\author{Margaret Meixner}
\affil{STScI, 3700 San Martin Dr., Baltimore, MD 21218, USA}

%-----------------------------------------------------------------------
%			 Contact Information
%-----------------------------------------------------------------------
% This information will not appear in the paper but will be used by
% the editors in case you need to be contacted concerning your
% submission.  Enter your name as the contact along with your email
% address.

\contact{Toshiya Ueta}
\email{ueta@oma.be}

%-----------------------------------------------------------------------
%		      Author Index Specification
%-----------------------------------------------------------------------
% Specify how each author name should appear in the author index.  The 
% \paindex{ } should be used to indicate the primary author, and the
% \aindex for all other co-authors.  You MUST use the following
% syntax: 
%
% SYNTAX:  \aindex{LASTNAME, F. M.}
% 
% where F is the first initial and M is the second initial (if
% used).  This guarantees that authors that appear in multiple papers
% will appear only once in the author index.  
%
% EXAMPLE: \paindex{Crabtree, D.}
%          \aindex{Manset, N.}
%          \aindex{Veillet, C.}
%
% NOTE: this information is also used to build the author list that
% appears in the table of contents.  Authors will be listed in the order
% of the \paindex and \aindex commmands.
%

\paindex{Ueta, T.}
\aindex{Murakawa, K.}     
\aindex{Meixner, M.}     

%-----------------------------------------------------------------------
%                     Author list for page header
%-----------------------------------------------------------------------
% Please supply a list of author last names for the page header. in
% one of these formats:
%
% EXAMPLES:
% \authormark{LASTNAME}
% \authormark{LASTNAME1 \& LASTNAME2}
% \authormark{LASTNAME1, LASTNAME2, ... \& LASTNAMEn}
% \authormark{LASTNAME et al.}
%
% Use the "et al." form in the case of seven or more authors, or if
% the preferred form is too long to fit in the header.

\authormark{Ueta, Murakawa, \& Meixner}

%-----------------------------------------------------------------------
%			Subject Index keywords
%-----------------------------------------------------------------------
% Enter up to 6 keywords describing your paper.  These will NOT be
% printed as part of your paper; however, they will be used to
% generate an object index and a subject index for the proceedings.  
% There is no standard list,  however, individual object names are
% encouraged and one or two word descriptions of the topics (e.g.MHD, 
% ionized gas) are useful. 
%
% EXAMPLE:  \keywords{NGC 7027, AFGL 2688, HD 161796, binary stars,
%                      dust,  molecular gas}

\keywords{IRAS 07134+1005, IRAS 06530-0213, IRAS 04296+3429, 
IRAS 02229+6208, dust, polarization, circumstellar shell}

%-----------------------------------------------------------------------
%			       Abstract
%-----------------------------------------------------------------------
% Type abstract in the space below.  Consult the User Guide and Latex
% Information file for a list of supported macros (e.g. for typesetting 
% special symbols). Do not leave a blank line between \begin{abstract} 
% and the start of your text.

\begin{abstract}          % Leave intact
We present the preliminary results from our {\sl HST}/NICMOS imaging 
polarimetry on optically thin PPNs.
The data show the dust distribution in an unprecedented detail.
The structure of these faint PPNs is revealed via polarization
properties of the dust-scattered light without much interference from
the bright central star, proving the unique advantages of the technique
over simple imaging. 
\end{abstract}

%-----------------------------------------------------------------------
%			      Main Body
%-----------------------------------------------------------------------
% Place the text for the main body of the paper here.  You should use
% the \section command to label the various sections; use of
% \subsection is optional.  Significant words in section titles should
% be capitalized.  Sections and subsections will be numbered
% automatically. 

\section{Introduction}

We observed 4 PPNs of SOLE type (Ueta et al.\ 2000) by means of imaging
polarimetry
using {\sl HST}/NICMOS (NIC1 with POL0S, POL120S, and POL240S filters)
during cycle 11 (GO 9377).
Our main objective was 
to study the dust distribution in these {\sl optically thin} 
PPN shells around the bright central star.
Imaging polarimetry (e.g., Gledhill et al.\ 2001) is a very effective
technique for this purpose because 
(1) bright stellar emission (unpolarized component) is
automatically removed when the linearly polarized component 
(i.e., dust-scattered star light of the reflection nebula) is
computed from the Stokes $Q$ and $U$ parameters,
(2) the dust distribution in the reflection nebula can be probed at high
resolution as opposed to the mid-IR diffraction-limit resolution,
and
(3) dust properties (e.g., the size distribution) can also be 
investigated. 

\section{Preliminary Results}

Figure \ref{fig1} shows imaging polarimetry 
data for IRAS 07134+1005 (left) and IRAS 06530-0213 (right).
The IRAS 07134+1005 data illustrate the distribution and
strength of polarization.
The four frames display, from top left to bottom right,
the total intensity (the Stokes $I$),
the polarized intensity ($I_{\rm pol} = \sqrt{Q^2 + U^2}$),
the degree of polarization ($I_{\rm pol}/I$),
and the 10.3 $\mu$m Gemini image (Kwok et al.\ 2002) 
for comparison.
The total and polarized intensity images look similar, suggesting that
the nebula emission consists mostly of scattered star light as expected
in this reflection nebula. 
The total intensity image confirms the equatorially 
enhanced (toroidal) structure of the shell as seen in the 
10.3 $\mu$m image and also shows the structure {\sl within} the 
reflection nebula in an unprecedented detail.
Such detailed structure of the shell was not seen well in 
{\sl HST}/WFPC2 data due to the invasively bright central star and its
enormous PSF spikes 
(Ueta et al.\ 2001).

In the IRAS 06530-0213 data,
the distribution and angles of polarization vectors
are displayed.
The four frames shows the the polarized intensity,
the distribution of polarization vectors of less than 30\% 
($I_{\rm pol}/I < 0.3$) strengths,
of 30 to 40\% strengths,
and of more than 40\% strengths,
from top left to bottom right.
The vectors are distributed in a clear centro-symmetric pattern
with respect to the central star. 
This confirms the optically thin nature of this PPN shell.
It is also apparent that the stronger polarization is found near the
edge of the shell.
This is because 
dust-scattered light near the nebula edge tends to have
near 90$^{\circ}$ scattering angle, and hence, tends to yield
the highest degree of polarization.
%It may also be related to the fact that these PPNs show 
%reflection nebulae having a rather sharp edge.
%We also recognize some point-symmetric structure in the way 
%these vectors are distributed.
Our data yielded rather high degrees of polarization in 
our target PPNs.
This may be due to a population of small dust grains 
residing in these shells.
We are currently finalizing our data analysis, and the results would
shed light on the PPN shell structure as well as the properties of dust
grains present in PPNs.

\begin{figure}
\epsscale{1}
\plottwo{ueta2_1.eps}{ueta2_2.eps}
\caption{%
Imaging polarimetry data of IRAS 07134+1005 (left) and
IRAS 06530-0123 (right).} \label{fig1}
\end{figure}

% You can also add an acknowledgments section as indicated below.

\acknowledgments

Support for GO-9377 was provided by NASA through a grant from
the STScI, which is operated by the AURA, Inc., under NASA
contract NAS 5-26555. 
Ueta was also supported by IUAP P5/36 financed by the OSTC 
of the Belgian Federal State.

%-----------------------------------------------------------------------
%			      References
%-----------------------------------------------------------------------
% List your references below within the reference environment
% (i.e. between the \begin{references} and \end{references} tags).
% Each new reference should begin with a \reference command which sets
% up the proper indentation.  Observe the following order when listing
% bibliographical information for each reference:  author name(s),
% publication year, journal name, volume, and page number for
% articles.  Note that many journal names are available as macros; see
% the User Guide for a listing "macro-ized" journals.   
%
% Note the following are some of the tricks that can be used:
%
%   o  \& is used to format an ampersand symbol (&).
%   o  \'e puts an accent grave over the letter e.  See the User Guide
%      for details on formatting special characters.  
%   o  "\ " after a period prevents LaTeX from interpreting the period 
%      as an end of a sentence.
%   o  \aj is a macro that expands to "Astron. J."  See the User Guide
%      for a full list of journal macros
%
\begin{references}
%\reference Gledhill, T.\ M., Chrysostomou, A., Hough, J.\ H., \& Yates, J.\ A.
\reference Gledhill, T.\ M., et al.
2001, \mnras, 322, 321
\reference Kwok, S., Volk, K., \& Hrivnak, B.\ J.
2002, \apj, 573, 720
\reference Ueta, T., Meixner, M., \& Bobrowsky, M.
2000, \apj, 528, 861
\end{references}

% Do not place any material after the references section

\end{document}  % Leave intact
