Early-type Host Galaxies of Type Ia Supernovae. I. Evidence for Downsizing

Type Ia supernova (SN Ia) cosmology provides the most direct evidence for the presence of dark energy. This result is based on the assumption that the look-back time evolution of SN Ia luminosity, after light-curve corrections, would be negligible. Recent studies show, however, that the Hubble residual (HR) of SN Ia is correlated with the mass and morphology of host galaxies, implying the possible dependence of SN Ia luminosity on host galaxy properties. In order to investigate this more directly, we have initiated spectroscopic survey for the early-type host galaxies, for which population age and metallicity can be more reliably determined from the absorption lines. As the first paper of the series, here we present the results from high signal-to-noise ratio (>100 per pixel) spectra for 27 nearby host galaxies in the southern hemisphere. For the first time in host galaxy studies, we find a significant (~3.9sigma) correlation between host galaxy mass (velocity dispersion) and population age, which is consistent with the "downsizing" trend among non-host early-type galaxies. This result is rather insensitive to the choice of population synthesis models. Since we find no correlation with metallicity, our result suggests that stellar population age is mainly responsible for the relation between host mass and HR. If confirmed, this would imply that the luminosity evolution plays a major role in the systematic uncertainties of SN Ia cosmology.Comment: Accepted for publication in ApJ

Recent Parental Death and Relationship Qualities Between Midlife Adults and Their Grown Children

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149257/1/jomf12549_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149257/2/jomf12549.pd

Family Ties and Subjective Aging in Later Life

Subjective aging refers to individuals’ understanding and expectations of aging-related changes. Although studies have consistently documented that subjective aging constructs are associated with individuals’ behaviors and well-being in later life, the link between one’s social environment and subjective aging beliefs remains understudied. This three-study dissertation examined how close social ties shape different subjective aging perceptions, by focusing on how individuals in later life view their aging-related changes in family contexts. Using data from the Boston Aging Together Study¸ the first study explored how health and relationship quality indicators are associated with aging perceptions of very old parents and their children. Findings indicated that individuals’ self-perceptions of aging were more similar within their age group. Very old parents’ self-perceptions of aging were associated with their own depressive symptoms as well as the children’s report of caregiver burden. Children’s self-perceptions of aging were only related to their own characteristics. The findings demonstrate some evidence for the interdependence of subjective aging experiences among very old parents and their children. The second study utilized data from the Korean Baby Boomer Panel Study to examine subjective aging experiences of married Korean baby boomers, namely, how their aging anxiety is shaped in the context of the parents’ and in-law’s financial and health characteristics in midlife. This study examined and found the cumulative effect, as well as the exposure effect, of the health and financial challenges of parents and in-laws on Korean baby boomers’ level of aging anxiety. Furthermore, frequency of contact moderated the effect of the financial condition of the poorest parent/in-law, such that individuals reporting more contact with the poorest parent/in-law showed higher levels of aging anxiety than those with less contact. Finally, drawing on three waves of quadrennial data (2008–2016) from the Health and Retirement Study, the third study examined how changes in health and relationship quality with a spouse over time contribute to aging perceptions of married older men and women. Multilevel models showed that there was no gender difference in self-perceptions of aging at baseline and how positive self-perceptions of aging changed over time. However, the changes in health and relationship quality affected men and women differently at both within-person and between-person level. Men’s self-perceptions of aging were particularly sensitive to changes in relationship quality, whereas women’s self-perceptions of aging were particularly sensitive to changes in functional limitations. In sum, the three studies aimed to form a cohesive body of work that examines multiple ways in which family members (i.e., spouse, parents, and children) mutually influence one another’s aging perceptions. The combination of findings provides support for adapting a life course framework in assessing individuals’ understanding of and attitudes toward own aging. Evidence suggests that interventions aimed at improving aging perceptions should investigate and target late-life family dynamics as one of the key components

Older adults with functional limitations and their use of telehealth during COVID-19

We investigated the association between functional limitations and telehealth use among older Medicare beneficiaries in 2020. We use logistic regression models to estimate associations between functional limitations and the use of technological tools (i.e., computers, Internet, telehealth). We consider Internet use and informal technological support as moderators for telehealth use. Respondents (N = 3151; Mage = 78.31) with more functional limitations were more likely to use video-based telehealth. Net of functional limitations, those with a consistent Internet use were more likely to use emails/texts/portal messages to communicate with a healthcare provider. Further, more functional limitations were associated with a higher probability of using emails/texts/portal messages, but only among respondents who received informal technological support. Healthcare access may have been more difficult for older adults with functional limitations during the COVID-19 pandemic, especially for those with little prior experience with the Internet, or those without friends/family to provide technological support.Nanyang Technological UniversityThis work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (P2CHD042849), National Institute on Aging (P30AG066614), and Nanyang Technological University (03INS001006C430)

Like Parent, Like Child? Aging Anxiety Among Married Korean Baby Boomers

Objectives: How intergenerational relationships influence individuals' views on aging remains understudied. This study investigated how multiple older family members' health and financial challenges may shape middle-aged adults' aging anxiety. Method: Married Korean baby boomers (N = 1,389) from the Korean Baby Boomer Panel Study reported on their own aging anxiety and rated each of their living parents' and in-laws' health and financial conditions. Using structural equation modeling, we examined how parents' and in-laws' health and financial challenges are associated with one's aging anxiety, and whether gender and frequency of intergenerational contact moderate the link. We expected worse health or financial conditions to be associated with higher levels of aging anxiety, and the effect to be more pronounced for women and those with more contact. Results: A worse financial condition of the poorest parent/in-law was associated with higher levels of aging anxiety, while worse health condition of the unhealthiest parent/in-law was associated with lower levels of aging anxiety. The same results were found when we considered the sum of all living parents' and in-laws' financial and health conditions. Frequency of contact moderated the effect of the financial condition of the poorest parent/in-law, such that individuals reporting more contact with the poorest parent/in-law showed higher levels of aging anxiety than those with less contact. There was no moderating effect of gender. Discussion: The findings highlight the role family ties play in shaping one's aging anxiety. Interventions aimed at improving views on aging through intergenerational interactions should target the quality of the intergenerational experience.N

Racial Differences in Early Parental Death, Midlife Life Problems, and Relationship Strain With Adult Children

Objectives: Black Americans typically experience the death of a parent earlier in the life course than do non-Hispanic Whites, and early parental death is known to hinder subsequent relationship outcomes. Whether early parental death may contribute to racial differences in midlife family relationships and the role midlife adults' current life problems play remain unexplored. Method: Using multilevel modeling, we examined how timing of parental death is associated with relationship strain with adult children and whether the association differs by midlife adults' life problems in Black (n = 166) and non-Hispanic White (n = 467) families from the Family Exchanges Study. Results: Losing a parent in childhood was associated with more relationship strain with adult children for Black midlife adults, but not for their non-Hispanic White counterparts. Among the bereaved, earlier timing of parental death was associated with more relationship strain with adult children only for Black midlife adults. In both bereaved and nonbereaved sample, participants' recent physical-emotional problems exacerbated the link between timing of parental death and relationship strain with adult children for Black midlife adults. Discussion: Experiencing the death of a parent in the early life course can be an added structural disadvantage that imposes unique challenges for Black Americans in midlife. Policies and programs aimed at supporting bereaved children may benefit relationships with their own children later in life, and addressing physical-emotional problems in midlife may be a viable intervention point for those midlife adults who experienced the death of a parent in the early life course.N

ENVIRONMENTAL DEPENDENCE OF TYPE IA SUPERNOVA LUMINOSITIES FROM THE YONSEI SUPERNOVA CATALOG

There is evidence that the luminosities of Type Ia supernova (SN Ia) depend on their environments. While the impact of this trend on estimating cosmological parameters is widely acknowledged, the origin of this correlation is still under debate. In order to explore this problem, we first construct the YONSEI (YOnsei Nearby Supernova Evolution Investigation) SN catalog. The catalog consists of 1231 spectroscopically confirmed SNe Ia over a wide redshift range (0.01 < z < 1.37) from various SN surveys and includes light-curve fit data from two independent light-curve fitters, SALT2 and MLCS2k2. For a sample of 674 host galaxies, we use the stellar mass and the star formation rate data in Kim et al. (2018). We find that SNe Ia in low-mass and star-forming host galaxies are 0.062 ± 0.009 m a g and 0.057 ± 0.010 m a g fainter than those in high-mass and passive hosts, after light-curve corrections with SALT2 and MLCS2k2, respectively. When only local environments of SNe Ia (e.g., locally star-forming and locally passive) are considered, this luminosity difference increases to 0.081 ± 0.018 m a g for SALT2 and 0.072 ± 0.018 m a g for MLCS2k2. Considering the significant difference in the mean stellar population age between the two environments, this result suggests that the luminosity evolution of SNe Ia with redshift is most likely the origin of the environmental dependence