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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Please join us for the Physics Colloquium today, at<b> 3:45 PM</b> in The Robert Smith Seminar Room. There will be a reception at
<b>3:30PM</b> in the Atrium. Details concerning the talk are as follows: <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Speaker</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif">: Dave Kieda (University of Utah)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Date: Tuesday, September 3, 2019<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Time:
<b>3:45PM</b><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Place: 1080 Physics Research Building, The Robert Smith Seminar Room<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Title: Toward the Development of Visible Band Astronomical Imaging with Multi-kilometer Baselines</span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:0in;background:white">
<span style="font-family:"Arial",sans-serif">Abstract: </span><span style="font-family:"Helvetica",sans-serif;color:#555555">Stars visible to the naked eye typically have angular diameters on the order of one milliarcsecond (mas), while a handful of red supergiants
extend for a few tens of mas. Revealing details across and outside stellar surfaces, such as starspots or transiting exoplanets, requires imaging with resolution measured in tens of
<br>
micro-arcseconds (mas). The Rayleigh criterion requires kilometer-scale interferometric baselines to achieve this level of angular resolution in the visible waveband. Astronomical imaging with multi-kilometer interferometry has previously been achieved only
by radio/sub-mm interferometers such as VLA, ALMA, VLBA, and the Event Horizon Telescope (EHT).<o:p></o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:0in;background:white">
<span style="font-family:"Helvetica",sans-serif;color:#555555">Recent advances in optical telescope design, photodetector efficiency, and high-speed electronic data recording and synchronization have created a new observational capability to achieve unprecedented
angular resolution for several thousand bright (m< 6) and hot (O/B/A) stars through a modern implementation of Stellar Intensity Interferometry (SII). During the next decade, arrays of optical telescopes will perform SII over multi-kilometer baselines, allowing
visible band imaging with an angular resolution better than 40 m arc-sec.<o:p></o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:0in;background:white;box-sizing: border-box;-webkit-font-smoothing: antialiased;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;text-align:start;widows: 2;-webkit-text-stroke-width: 0px;text-decoration-style: initial;text-decoration-color: initial;word-spacing:0px">
<span style="font-family:"Helvetica",sans-serif;color:#555555">In this talk, I will describe science investigations that will be enabled by m arc-sec astronomical imaging in the visible. This observational capability can provide new insight in a broad range
of astrophysical topics including stellar structure and evolution, improvements in exoplanet mass estimation, and the direct imaging of fast stellar rotators and high-mass binary systems. We describe recent advances in the development of the technique, including
recent ~500 m arc-sec measurements of stellar diameters performed by the VERITAS-SII observatory in Spring 2019. The talk also describes the expected optical imaging resolution of VERITAS-SII and the future kilometer-baseline CTA IACT Observatory (Canary Islands,
Spain and Paranal, Chile). We conclude with potential capabilities of future Very Large Intensity Interferometer (VLII), which could employ a reconfigurable array of optical telescopes deployed in multi-kilometer baselines. VLII would allow field of view and
angular resolution to be reconfigured to meet the requirements for specific astronomical targets, analogous to VLA and ALMA. <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white;box-sizing: border-box;-webkit-font-smoothing: antialiased;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;text-align:start;widows: 2;-webkit-text-stroke-width: 0px;text-decoration-style: initial;text-decoration-color: initial;word-spacing:0px">
<span style="font-family:"Helvetica",sans-serif;color:#555555"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">The website for the colloquium is
<a href="https://physics.osu.edu/physics-colloquium-schedule"><span style="color:#0563C1">https://physics.osu.edu/physics-colloquium-schedule</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Also, there is the speaker/student discussion starting just after the colloquium, at 4:45pm in the Smith Seminar Room.</span><span style="font-family:Papyrus;color:#0070C0"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Papyrus;color:#0070C0"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Papyrus;color:#0070C0"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Papyrus;color:#0070C0"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Segoe Script";color:blue">Robin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0"><img border="0" width="224" height="45" style="width:2.3333in;height:.4687in" id="Picture_x0020_1" src="cid:image001.png@01D56237.DA281180" alt="The Ohio State University"><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;line-height:13.5pt;background:white">
<b><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#BB0000;background:white">Robin Patterson</span></b><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#333333"><br>
Program Coordinator<br>
</span><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#BB0000;background:white">Department of Physics</span><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#333333">
<br>
1040K Physics Research Building, 191 W. Woodruff Avenue, Columbus, OH 43210<br>
(614) 292-8523 Office (614) 292-7557 Fax<br>
</span><u><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:blue;background:white"><a href="mailto:patterson.716@osu.edu">patterson.716@osu.edu</a></span></u><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#333333">
<a href="http://osu.edu/"><span style="color:blue;background:white">osu.edu</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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