Browsing by Author "Salinas, R."
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- ItemA Segmented Period-Luminosity Relation for Nearby Extragalactic Delta Scuti Stars(2022) Martínez-Vázquez, C. E.; Salinas, R.; Vivas, A. K.; Catelan , MarcioThe period-luminosity relations (PLRs) of Milky Way δ Scuti (δ Sct) stars have been described to the present day by a linear relation. However, when studying extragalactic systems such as the Magellanic Clouds and several dwarf galaxies, we notice for the first time a nonlinear behavior in the PLR of δ Sct stars. Using the largest sample of ~3700 extragalactic δ Sct stars from data available in the literature-mainly based on the Optical Gravitational Lensing Experiment and the Super MAssive Compact Halo Object project in the Large Magellanic Cloud (LMC)-we obtain that the best fit to the period-luminosity (M V ) plane is given by the following piecewise linear relation with a break at logP = -1.03 ± 0.01 (or 0.093 ± 0.002 days) for shorter periods (sp) and longer periods (lp) than the break-point:...
- ItemAn AO-assisted variability study of four globular clusters(2016) Salinas, R.; Contreras Ramos, Rodrigo Andrés; Strader, J.; Hakala, P.; Catelan, Márcio; Peacock, M. B.; Simunovic , M.
- ItemConsideraciones acerca de la “interrupción voluntaria del embarazo”, desde el punto de vista ético-médico (a propósito de un proyecto de ley)(2015) Echeverria, C.; Serani Merlo, Alejandro; Arriagada, A.; Goic, A.; Herrera, C.; Quintana Villar, Carlos; Rojas, A.; Ruiz, G.; Salinas, R.; Taboada R., Paulina; Vacarezza, R.
- ItemDisentangling multiple stellar populations in globular clusters using the Strömgren system(2015) Alonso-García, J.; Catelan, Márcio; Amigo, P.; Cortés, C.; Kuehn, C. A.; Grundahl, F.; López, G.; Salinas, R.; Smith, H. A.; Stetson, P. B.; Sweigart, Allen V.; Valcarce, Aldo A. R.; Zoccali, M.An increasing amount of spectroscopic and photometric evidence is showing that the stellar populations of globular clusters are not as simple as they have been considered for many years. The presence of at least two different populations of stars is being discovered in a growing number of globular clusters, both in our Galaxy and in others. We have started a series of observations of Galactic globular clusters using the Strömgren photometric system in order to find the signatures of these multiple populations and establish their presence in a more complete sample of globular clusters in the Milky Way, and to study their radial distributions and extensions. We present here the first results of our survey....
- ItemDoes therapeutic privilege have a place in modern medicine?(2017) Salinas, R.; Echeverría, C.; Arriagada A.; Goic, A.; Quintana Villar, Carlos; Rojas, A.; Serani Merlo, Alejandro; Taboada R., Paulina; Vacarezza, R.
- ItemMultiple populations in Galactic globular clusters from a Strömgren perspective(2014) Alonso-García, J.; Catelan, Márcio; Amigo, P.; Cortés, C.; Kuehn, C. A.; Grundahl, F.; López, G.; Salinas, R.; Smith, H. A.; Stetson, P. B.; Sweigart, Allen V.; Valcarce, Aldo A. R.; Zoccali, M.Our view of the stellar populations in globular clusters has radically changed in the last years. Now we are coming to believe that all globular clusters host at least two distinct stellar populations. We present in this contribution preliminary results of a photometric survey we are currently conducting to disentangle photometrically the several populations in a significant number of Galactic globular clusters, using the Strömgren system, aiming to characterize their relative ratios and their radial distributions....
- ItemMultiple populations in Galactic globular clusters: a survey in the Strömgren system(2013) Alonso-García, J.; Catelan, Márcio; Amigo, P.; Cortés, C.; Kuehn, C. A.; Grundahl, F.; López, G.; Salinas, R.; Smith, H. A.; Stetson, P. B.; Sweigart, Allen V.; Valcarce, Aldo A. R.; Zoccali, M.We are coming to believe that stellar populations in globular clusters are not as simple as they were once thought to be. A growing amount of photometric and spectroscopic evidence shows that globular clusters host at least two different stellar populations. In our contribution to these proceedings we present the first results of a survey we are conducting to look for the presence of multiple populations in a significant number of Galactic globular clusters, using the Strömgren system. We intend to photometrically separate these populations and characterize their radial distributions and extensions....
- ItemNewly Discovered Variable Stars in the Globular Clusters Ngc 5634, Arp 2 and Terzan 8(2005) Salinas, R.; Catelan, Márcio
- ItemStellar variability at the main-sequence turnoff of the intermediate-age LMC cluster NGC 1846(2018) Salinas, R.; Pajkos, M.A.; Vivas, A.K.; Strader, J.; Contreras Ramos, Rodrigo Andrés
- ItemStructural parameters and blue stragglers in Sagittarius dwarf spheroidal galaxy globular clusters(2012) Salinas, R.; Catelan, Márcio; Amigo Fuentes, Pía
- ItemThe curious case of the companion : evidence for cold accretion onto a dwarf satellite near the isolated elliptical NGC 7796(2018) Richtler, T.; Hilker, M.; Voggel, K.; Puzia, Thomas H.; Salinas, R.; Gómez, M.; Lane, R.
- ItemTHE OVERLOOKED ROLE OF STELLAR VARIABILITY IN THE EXTENDED MAIN SEQUENCE OF LMC INTERMEDIATE-AGE CLUSTERS(2016) Salinas, R.; Pajkos, M. A.; Strader, J.; Vivas, A. K.; Ramos, R. ContrerasIntermediate-age star clusters in the Large Magellanic Cloud show extended main sequence turnoffs (MSTOs) that are not consistent with a canonical single stellar population. These broad turnoffs have been interpreted as evidence for extended star formation and/or stellar rotation. Since most of these studies use single frames per filter to do the photometry, the presence of variable stars near the MSTO in these clusters has remained unnoticed and their impact has been totally ignored. We model the influence of Delta Scuti using synthetic CMDs, adding variable stars following different levels of incidence and amplitude distributions. We show that Delta Scuti observed at a single phase will produce a broadening of the MSTO without affecting other areas of a CMD such as the upper MS or the red clump; furthermore, the amount of spread introduced correlates with cluster age, as observed. This broadening is constrained to ages similar to 1-3 Gyr when the MSTO area crosses the instability strip, which is also consistent with observations. Variable stars cannot explain bifurcarted MSTOs or the extended MSTOs seen in some young clusters, but they can make an important contribution to the extended MSTOs in intermediate-age clusters.
- ItemThe Sagittarius dSph globular cluster system: variable stars(2006) Salinas, R.; Catelan, Marcio; Smith, H. A.; Pritzl, B. J.; Borissova, J.We have applied the image subtraction technique to images of four globular clusters which have been suggested to be associated with the Sagittarius dSph galaxy: Arp, NGC634, Palomar2 and Terzan. As a result we have a found a sizeable population of variable stars incluiding RR Lyrae and SX Phoenicis stars in the globular clusters Arp, NGC634 and Terzan. We do not confirm the presence of variable stars that has been previously claimed in Palomar2. In NGC634 we have found 19 RR Lyrae stars (six previously known), and 1 SXstar. Although the real amplitudes of all the variables are not completely determined, the Bailey diagram for the RRab stars, together with the mean of its periods <P_{ab}> = 0.639 d, confirm the Oosterhoff II classification for this cluster. In Arp 2 we have found 9 RRL stars (four previously known) and 3 SXPhe stars. If we only consider the mean period of the RRab stars, <P_{ab}> = 0.593 d, we can classify this cluster as Oosterhoff-intermediate. However, the Bailey diagram does not support this classification, because only one out of eight RRab stars are located in the intermediate region. The RRL specific frequency for this cluster is S_{RR} = 68.8, the highest of all Sagittarius-related globulars, which could be a hint that some of the studied RRL are not Arp members but rather Sagittarius field stars....
- ItemVariable Stars in Sagittarius Globular Clusters. I. Arp 2(2019) Pritzl, B. J.; Gehrman, T. C.; Salinas, R.; Catelan, Márcio; Smith, H. A.; Borissova, J.