Galaxies and Supermassive Black Holes Evolving in a Secular Universe

Most massive galaxies host a supermassive black hole (BH), that had most of its mass built up throughout bright periods of vigorous accretion, during which it is referred to as an active galactic nucleus (AGN). In the local universe it has been observed that BH mass (M_BH) follows tight correlations with various properties of the galactic bulge in which it resides. This led to the currently popular co-evolution'' picture, in which most present-day galaxies went through at least one active phase in the past, during which a link between galaxy and BH gets established. However, more robust observational constraints are required on how galaxy and BH related at earlier times, and which mechanism is responsible for triggering these BH growth phases. This thesis studies a large sample of AGN out to z~1 from the COSMOS survey, selected from their X-ray emission and imaged in finest detail with the Hubble Space Telescope, allowing the study of growing BHs together with their host galaxies. We present new constraints on the ratio of BH mass to total galaxy stellar mass (M_*) over the last 7 Gyr for 32 type-1 AGN. We show that the M_BH-M_* ratio at z~0.7 is consistent with the local relation between BH mass and galactic bulge mass. For these galaxies to obey the local relation only a redistribution of disk-to-bulge mass is needed, likely driven by passive secular evolution. We then tackle and answer a 30-year old question: what is the relevance of major mergers and interactions as triggering mechanisms for AGN activity? We visually analyze the morphologies of 140 AGN out to z~1 looking for signatures of recent mergers, and compare them with a control sample of over 1200 matched inactive galaxies. We find that the merger fraction of the AGN host galaxies is statistically identical to the corresponding inactive galaxy population, at roughly 15%. Together with the fact that the majority of the AGN host galaxies are disk-dominated, unlikely relics of a recent major merger, these results are the strongest evidence to date that secular evolution rather than major merging has dominated BH fueling at least since z~1, and that BHs and galaxies have, for the last 7 Gyr, evolved in a secular universe

Myrosmodes nervosa (Orchidaceae, Cranichidinae, subgenus Myrosmodes): nueva combinación de Myrosmodes para Chile

De acuerdo a datos macromorfológicos y de hábitat se transfiere Altensteinia nervosa Kraenzl. al género Myrosmodes. Se describela especie y se establece el tipo.De acuerdo a datos macromorfológicos y de hábitat se transfiere Altensteinia nervosa Kraenzl. al género Myrosmodes. Se describela especie y se establece el tipo

Breakdown of species boundaries in Mandevilla: Floral morphological intermediacy, novel fragrances and asymmetric pollen flow

Phenotypic intermediacy is an indicator of putative hybrid origin, and has provided the main clues to discovering hybrid plants in nature. Mandevilla pentlandiana and M. laxa (Apocynaceae) are sister species with clear differences in floral phenotype and associated pollinator guilds: diurnal Hymenoptera and nocturnal hawkmoths, respectively. The presence of individuals with intermediate phenotypes in a wild population raises questions about the roles of visual and olfactory signals (i.e. corolla morphology and floral fragrances) as barriers to interbreeding, and how the breakdown of floral isolation occurs.We examined phenotypic variation in a mixed Mandevilla population analysing the chemical composition of floral fragrances, characterizing floral shape through geometric morphometrics and assessing individual grouping through taxonomically relevant traits and an unsupervised learning algorithm. We quantified the visitation frequencies of floral visitors and tracked their foraging movements using pollen analogues.The presence of morphologically intermediate individuals and pollen analogue movement suggested extensive hybridization between M. laxa and M. pentlandiana, along with asymmetrical rates of backcrossing between these putative hybrids and M. laxa. Floral volatiles from putative hybrid individuals showed a transgressive phenotype, with additional compounds not emitted by either parental species.Our results suggest the presence of a hybrid swarm between sympatric M. pentlandiana and M. laxa and indicate that initial hybridization events between these parental species are rare, but once they occur, visits between putative hybrids and M. laxa are common and facilitate continued introgression.Fil: Rubini Pisano, María Aimé. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: More, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Cisternas, Mauricio. Jardín Botánico Nacional; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Raguso, Robert A.. Cornell University; Estados UnidosFil: Benitez-Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Association between the Mediterranean Diet Index and self-reported Gingival Health Status Indicators in a population of Chilean adults: a cross-sectional study

Despite the recognized impact of diet on non-communicable diseases, the association between the Mediterranean diet and periodontal diseases is still uncertain. This study aimed to determine the association between adherence to the Mediterranean Diet Index (MDI) and self-reported gingival health status in Chilean adults, exploring the feasibility of using validated web-based survey questionnaires. Methodology: Cross-sectional data were collected from a representative sample of a population of Chilean adults (18-60 years old) using a low-cost and time-saving methodology. By the PsyToolkit platform, anonymous survey data were downloaded and analyzed in bivariate (crude) and backward stepwise selection multivariate logistic regression models adjusted for sociodemographic determinants, smoking, and dental attendance using STATA 17. Odds ratios (OR) [95% confidence intervals] were estimated. Results: In total, 351 complete statistical data were mostly obtained from female university students who had never smoked and reported having visited a dentist in the previous year. Multivariate regression models showed an association between MDI and very good/good gingival health status (OR 1.18 [95% CI 1.04-1.34], p=0.013), absence of bleeding on toothbrushing (OR 1.12 [95% CI 1.01-1.25], p=0.035), and absence of clinical signs of gingival inflammation (OR 1.24 [95% CI 1.10-1.40], p<0.001), after controlling for age, sex, educational level, smoking, and dental attendance. Conclusions: We associated adherence to the Mediterranean diet with better self-reported gingival health status in a population of Chilean adults in an entirely web-based research environment. Longitudinal studies with random sampling are required to establish the effect of diet on gingival and periodontal health. Nevertheless, this evidence could contribute to the design of low-cost surveillance programs to reduce the burden of periodontal disease and related “common risk factors”

The Role of Bars in AGN Fueling in Disk Galaxies Over the Last Seven Billion Years

We present empirical constraints on the influence of stellar bars on the fueling of active galactic nuclei (AGNs) out to z = 0.84 using a sample of X-ray-selected AGNs hosted in luminous non-interacting face-on and moderately inclined disk galaxies from the Chandra COSMOS survey. Using high-resolution Hubble Space Telescope imaging to identify bars, we find that the fraction of barred active galaxies displays a similar behavior as that of inactive spirals, declining with redshift from 71% at z∼ 0.3, to 35% at z∼ 0.8. With active galaxies being typically massive, we compare them against a mass-matched sample of inactive spirals and show that, while at face value the AGN bar fraction is slightly higher at all redshifts, we cannot rule out that the bar fractions of active and inactive galaxies are the same. The presence of a bar has no influence on the AGN strength, with barred and unbarred active galaxies showing equivalent X-ray luminosity distributions. From our results, we conclude that the occurrence and the efficiency of the fueling process is independent of the large scale structure of a galaxy. The role of bars, if any, may be restricted to providing the suitable conditions for black hole fueling to occur, i.e., bring a fresh supply of gas to the central 100 pc. At the high-redshift end, we find that roughly 60% of active disk galaxies are unbarred. We speculate this to be related with the known dynamical state of disks at higher redshifts—more gas-rich and prone to instabilities than local spirals—which could also lead to gas inflows without the need of bars

H-alpha kinematics of S4G spiral galaxies-II. Data description and non-circular motions

We present a kinematical study of 29 spiral galaxies included in the Spitzer Survey of Stellar Structure in Galaxies, using Halpha Fabry-Perot data obtained with the Galaxy Halpha Fabry-Perot System instrument at the William Herschel Telescope in La Palma, complemented with images in the R-band and in Halpha. The primary goal is to study the evolution and properties of the main structural components of galaxies through the kinematical analysis of the FP data, complemented with studies of morphology, star formation and mass distribution. In this paper we describe how the FP data have been obtained, processed and analysed. We present the resulting moment maps, rotation curves, velocity model maps and residual maps. Images are available in FITS format through the NASA/IPAC Extragalactic Database and the Centre de Donn\'ees Stellaires. With these data products we study the non-circular motions, in particular those found along the bars and spiral arms. The data indicate that the amplitude of the non-circular motions created by the bar does not correlate with the bar strength indicators. The amplitude of those non-circular motions in the spiral arms does not correlate with either arm class or star formation rate along the spiral arms. This implies that the presence and the magnitude of the streaming motions in the arms is a local phenomenon.Comment: 23 pages, 14 figures, without appendices, accepted to be published in MNRA

The bulk of the black hole growth since z ~ 1 occurs in a secular universe: no major merger-AGN connection

What is the relevance of major mergers and interactions as triggering mechanisms for active galactic nuclei (AGNs) activity? To answer this long-standing question, we analyze 140 XMM-Newton-selected AGN host galaxies and a matched control sample of 1264 inactive galaxies over z ~ 0.3–1.0 and M_∗ < 10^(11.7) M_⊙ with high-resolution Hubble Space Telescope/Advanced Camera for Surveys imaging from the COSMOS field. The visual analysis of their morphologies by 10 independent human classifiers yields a measure of the fraction of distorted morphologies in the AGN and control samples, i.e., quantifying the signature of recent mergers which might potentially be responsible for fueling/triggering the AGN. We find that (1) the vast majority (>85%) of the AGN host galaxies do not show strong distortions and (2) there is no significant difference in the distortion fractions between active and inactive galaxies. Our findings provide the best direct evidence that, since z ~ 1, the bulk of black hole (BH) accretion has not been triggered by major galaxy mergers, therefore arguing that the alternative mechanisms, i.e., internal secular processes and minor interactions, are the leading triggers for the episodes of major BH growth.We also exclude an alternative interpretation of our results: a substantial time lag between merging and the observability of the AGN phase could wash out the most significant merging signatures, explaining the lack of enhancement of strong distortions on the AGN hosts. We show that this alternative scenario is unlikely due to (1) recent major mergers being ruled out for the majority of sources due to the high fraction of disk-hosted AGNs, (2) the lack of a significant X-ray signal in merging inactive galaxies as a signature of a potential buried AGN, and (3) the low levels of soft X-ray obscuration for AGNs hosted by interacting galaxies, in contrast to model predictions