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<p>A toda la comunidad, <br>
</p>
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<p>les recordamos que hoy a las 13h, en el Salón Meridiano, se
brindará la siguiente charla en el marco de los Seminarios de la
FCAG:<b> Hunting for the first stars in the Universe with S-PLUS</b>.<b>
</b>La misma estará a cargo del Dr. Felipe de Almeida Fernandes
(IAG, Universidad de Sao Paulo, Brasil), profesor invitado del
Grupo ALAS. A continuación les dejamos el resumen y los datos de
conexión para aquellos que no puedan acercarse al Salón
Meridiano.<b> <br>
</b></p>
<p><b>Resumen: </b>Metal-poor stars are key to our understanding
of the early stages of chemical evolution in the Universe. New
multifilter surveys, such as the Southern Photometric Local
Universe Survey (S-PLUS), are greatly advancing our ability to
select low-metallicity stars in our Galaxy. In a series of
papers, we have selected and analyzed a sample of 522 metal-poor
candidates in S-PLUS. Follow-up observations in Blanco and
Gemini South telescopes, using the COSMOS and GMOS
spectrographs, confirmed that 92% of the selected stars have
[Fe/H] < -1, while 83% have [Fe/H] < -2, and 15% [Fe/H]
< -3. Our sample also includes two stars with spectroscopic
metallicity below -4. Based on this sample, we proposed further
selection criteria by combining S-PLUS and Gaia DR3 data and
showed that we were able to improve the purity of the selection,
achieving fractions of 99.5% and 91% for [Fe/H] ≤ -1 and [Fe/H]
≤ -2, respectively. We also performed high-resolution
spectroscopic follow-ups for two peculiar stars in the sample:
i) SPLUS J2104−0049 was observed in the Magellan-Clay telescope
and found to be the ultra metal-poor star ([Fe/H] < -4) with
the lowest ever detected carbon abundance (at the time of our
publication). ii) More recently, SPLUS J1424-2542 was observed
during the system verification of the GHOST instrument,
installed at the Gemini South telescope. Our preliminary results
reveal that this star is not only a metal-poor star with low
carbon abundance, but is also enriched in r-process elements. </p>
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<p dir="ltr"
style="line-height:1.3800000000000001;text-align: justify;margin-top:0pt;margin-bottom:0pt;"><b
style="font-weight:normal;"
id="docs-internal-guid-9900c2c0-7fff-a3eb-cd2d-42c502fb9543"><b
style="font-weight:normal;"
id="docs-internal-guid-84bbdb09-7fff-3b80-37a8-3bd0810a2176"><b>Datos
de conexión:</b> </b></b></p>
<b style="font-weight:normal;"
id="docs-internal-guid-9900c2c0-7fff-a3eb-cd2d-42c502fb9543"> </b>
<b style="font-weight:normal;"
id="docs-internal-guid-84bbdb09-7fff-3b80-37a8-3bd0810a2176"> </b>
<b style="font-weight:normal;"
id="docs-internal-guid-84bbdb09-7fff-3b80-37a8-3bd0810a2176"> </b>
<div><b style="font-weight:normal;"
id="docs-internal-guid-84bbdb09-7fff-3b80-37a8-3bd0810a2176">
</b></div>
<div>Unirse a la reunión zoom: <a
href="https://us02web.zoom.us/j/89642687970"
class="moz-txt-link-freetext" moz-do-not-send="true">https://us02web.zoom.us/j/89642687970</a>
</div>
<div>ID de reunión: 896 4268 7970</div>
<div>Código de acceso: 526656</div>
<div><br>
</div>
<div><b>A fin de reducir el uso de residuos plásticos, les
solicitamos que se acerquen con sus propias tazas para el
café.</b></div>
<div>Aunque este seminario será en formato híbrido, esperamos
contar con su presencia.</div>
<p> Saludos, <br>
</p>
<p>Secyt-FCAG</p>
<pre class="moz-signature" cols="72">--
Secretaría de Ciencia y Técnica
Facultad de Ciencias Astronómicas y Geofísicas
Horario de atención: lunes a viernes de 8hs a 15hs</pre>
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