<html>
<head>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 10 (filtered)">
<style>
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 77.95pt 1.0in 77.95pt;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=EN-US link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>ALMA Memo # 499</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>An Approach Detecting the Event Horizon of SgrA* </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Makoto Miyoshi</span></font>, Seiji Kameno, Jose K. Ishitsuka</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>(National Astronomical Observatory, Mitaka, </span></font>Tokyo, Japan)</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Zhi-Qiang Shen</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>(</span></font>Shanghai Astronomical Observatory, Chinese Academy of
Sciences, Shanghai)</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Rohta Takahashi</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>(Yukawa Institute for Theoretical Physics, </span></font>Kyoto
University, Japan)</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Shinji Horiuchi</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>(Center for Astrophysics and Supercomputing, Swinburne </span></font>University
of Technology,Victoria, Australia) </p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>2004-05-20 </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Keywords: black hole, event horizon, SgrA*, submillimeter VLBI</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Imaging the vicinity of a black hole is one of the ultimate goals of
VLBI astronomy. The closest massive black hole, SgrA*, located at the Galactic
center is the leading candidate for such observations. Combined with recent
VLBI recording technique and submillimeter radio engineering, we now have the
sufficient sensitivity for the observations. Here we show performance
simulations of submillimeter VLBI arrays for imaging SgrA*. Good images are
obtained from submillimeter VLBI arrays in the southern hemisphere composed of
more than 10 stations. We also note that even with a small array, we can
estimate the shadow size and then the mass of black hole from visibility
analysis. Now, all we need is to construct a submillimeter VLBI array in the
southern hemisphere if we wish to unveil the black hole environment of SgrA*. </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>View a pdf version of ALMA Memo #499. </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>http://www.alma.nrao.edu/memos/html-memos/alma499/memo499.pdf</span></font></p>
</div>
</body>
</html>