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<p class="MsoNormal"><b><span style="font-size:20.0pt;color:black;mso-ligatures:none">Physics and Astronomy Seminar<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="color:#00B050;mso-ligatures:none">10:30am, Tuesday, Aug. 6, 2024, Science Building 103</span></b><b><span style="font-size:12.0pt;color:#00B050;mso-ligatures:none"><o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:20.0pt;color:black;mso-ligatures:none">Magnetar QPOs and crustal torsional oscillations<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:20.0pt;color:black;mso-ligatures:none">Dr. Hajime Sotani<o:p></o:p></span></p>
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</v:shapetype><v:shape id="Picture_x0020_2" o:spid="_x0000_s1026" type="#_x0000_t75" alt="Photo of Hajime Sotani" style='position:absolute;margin-left:0;margin-top:24.75pt;width:118.05pt;height:147.5pt;z-index:251659264;visibility:visible;mso-wrap-style:square;mso-width-percent:0;mso-height-percent:0;mso-wrap-distance-left:9pt;mso-wrap-distance-top:0;mso-wrap-distance-right:9pt;mso-wrap-distance-bottom:0;mso-position-horizontal:absolute;mso-position-horizontal-relative:text;mso-position-vertical:absolute;mso-position-vertical-relative:text;mso-width-percent:0;mso-height-percent:0;mso-width-relative:page;mso-height-relative:page'>
<v:imagedata src="cid:image001.jpg@01DAE67E.654B9190" o:title="Photo of Hajime Sotani" />
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</v:shape><![endif]--><![if !vml]><img width="157" height="197" style="width:1.6354in;height:2.052in" src="cid:image001.jpg@01DAE67E.654B9190" align="left" hspace="12" alt="Photo of Hajime Sotani" v:shapes="Picture_x0020_2"><![endif]><span style="font-size:20.0pt;color:black;mso-ligatures:none">RIKEN
</span><span style="font-size:16.0pt;color:black;mso-ligatures:none">(</span><span style="font-size:16.0pt;font-family:Roboto;color:black;background:white">Japan National Research and Development Agency)</span><span style="font-size:16.0pt;color:black;mso-ligatures:none"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">Abstract:</span><span style="font-size:20.0pt;color:black;mso-ligatures:none"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">Neutron stars are one of the most suitable environments for probing physics under extreme states. For example, the quasi-periodic oscillations (QPOs) observed in a giant flare occurred in a strongly
magnetized neutron star (magnetar), are carrying crucial information for extracting the neutron star properties. To theoretically explain the observed QPOs from magnetars, we systematically examine the crustal torsional oscillations, neglecting the magnetic
effects. We find that the observed QPOs can be identified well with crustal oscillations together with the nuclear saturation parameters. Then, we can constrain the so-called slope parameter, L. In addition, we consider the high-frequency QPOs observed in
GRB 200415A. By identifying the observed QPOs, we can inversely constrain the neutron star mass and radius for GRB 200415A by comparing them to the values of nuclear saturation parameters obtained from terrestrial experiments. </span><span style="font-size:12.0pt;color:black;mso-ligatures:none"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none"><o:p> </o:p></span></p>
<p class="MsoNormal">ChatGPT: Dr. Hajime Sotani is an astrophysicist in Japan, affiliated with RIKEN. His research focuses on various aspects of astrophysics, including neutron stars, black holes, and gravitational waves. Dr. Sotani has published numerous papers
contributing to the understanding of the fundamental properties and behaviors of these celestial objects. His work often involves collaborations with other leading scientists in the field. Detailed information about his research can be found at
<a href="https://inspirehep.net/authors/988012?ui-citation-summary=true&ui-exclude-self-citations=true">
https://inspirehep.net/authors/988012?ui-citation-summary=true&ui-exclude-self-citations=true</a><span style="mso-fareast-language:EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">BIO<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2004.3. Ph.D @ Waseda University (supervisor: Kei-ichi Maeda)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2004.4.-2006.3. Assistant prof. @ Waseda Univ.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2006.4.-2008.3. Marie-Currie Fellow @ University of Thessaloniki (Kostas Kokktas)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2008.4.-2010.5. Postdoc fellow @ University of Tuebingen (Kostas Kokkotas)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2010.6.-2012.10. Postdoc fellow @ National Astronomical Observatory of Japan (NAOJ)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2012.11.-2014.6. Specially Appointed Assistant Professor @ Yukawa Institute, Kyoto Univ.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2014.7.-2019.6. Specially Appointed Assistant Professor @ NAOJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2019.7.-2019.10. Specially Appointed researcher @ NAOJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2019.11.-2024.9. Researcher @ RIKEN<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;mso-ligatures:none">2024.10.- Associate professor @ Kochi Univ.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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