اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدRelative frequencies of supernovae types: dependence on host galaxy magnitude, galactocentric radius and local metallicity
55
0
0.0
(
0
)
تأليف
S. Boissier
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Context: Stellar evolution theory suggests that the relationship between number ratios of supernova (SN) types and metallicity holds important clues as to the nature of the progenitor stars (mass, metallicity, rotation, binarity, etc). Aims: We investigate the metallicity dependence of number ratios of various SN types, using a large sample of SN along with information on their radial position in, and magnitude of, their host galaxy. Methods: We derive typical galaxian metallicities (using the well known metallicity-luminosity relation) and local metallicities, i.e. at the position of the SN; in the latter case, we use the empirical fact that the metallicity gradients in disk galaxies are ~ constant when expressed in dex/R25. Results: We confirm a dependence of the N(Ibc)/N(II) ratio on metallicity; recent single star models with rotation and binary star models with no rotation appear to reproduce equally well that metallicity dependence. The size of our sample does not allow significant conclusions on the N(Ic)/N(Ib) ratio. Finally, we find an unexpected metallicity dependence of the ratio of thermonuclear to core collapse supernovae, which we interpret in terms of the star formation properties of the host galaxies.
قيم البحث
اقرأ أيضاً
Gravitational microlensing is currently the only technique that helps study the Galactic distribution of planets as a function of distance from the Galactic center. The Galactic location of a lens system can be uniquely determined only when at least
two of the three quantities that determine the mass--distance relations are measured. However, even if only one mass--distance relation can be obtained, a large sample of microlensing events can be used to statistically discuss the Galactic distribution of the lenses. In this study, we extract the Galactic distribution of planetary systems from the distribution of the lens-source proper motion, $mu_{rm rel}$, for a given Einstein radius crossing time, $t_{rm E}$, measured for the 28 planetary events in the statistical sample by Suzuki et al. (2016). Because microlensing is randomly caused by stars in our Galaxy, the observational distribution can be predicted using a Galactic model. We incorporate the planet-hosting probability, $P_{rm host} propto M_{rm L}^m R_{rm L}^r$, into a Galactic model for random-selected stars, where $M_{rm L}$ is the lens mass ($sim$ host mass), and $R_{rm L}$ is the Galactocentric distance. By comparing the observed distribution with the model-predicted $mu_{rm rel}$ distribution for a given $t_{rm E}$ at various combinations of $(m ,r)$, we obtain an estimate $r = 0.2 pm 0.4$ under a plausible uniform prior for $m$ of $0<m<2$. This indicates that the dependence of the planet frequency on the Galactocentric distance is not large, and suggests that the Galactic bulge does have planets.
We present the dependences of the properties of type Ia Supernovae (SNe Ia) on their host galaxies by analyzing the multi-band lightcurves of 118 spectroscopically confirmed SNe Ia observed by the Sloan Digital Sky Survey (SDSS) Supernova Survey and
the spectra of their host galaxies. We derive the equivalent width of the rm{H}$alpha$ emission line, star formation rate, and gas-phase metallicity from the spectra and compare these with the lightcurve widths and colors of SNe Ia. In addition, we compare host properties with the deviation of the observed distance modulus corrected for lightcurve parameters from the distance modulus determined by the best fit cosmological parameters. This allows us to investigate uncorrected systematic effects in the magnitude standardization. We find that SNe Ia in host galaxies with a higher star formation rate have synthesized on average a larger $^{56}$Ni mass and show wider lightcurves. The $^{56}$Ni mass dependence on metallicity is consistent with a prediction of Timmes et al. 2003 based on nucleosynthesis. SNe Ia in metal-rich galaxies ({$log_{10}(O/H)+12>8.9$) have become 0.13 $pm$ 0.06 magnitude brighter after corrections for their lightcurve widths and colors, which corresponds to up to 6% uncertainty in the luminosity distance. We investigate whether parameters for standardizing SN Ia maximum magnitude differ among samples with different host characteristics. The coefficient of the color term is larger by 0.67 $pm$ 0.19 for SNe Ia in metal-poor hosts than those in metal-rich hosts when no color cuts are imposed.
Type Ia supernovae (SNe Ia) are standardizable candles, but for over a decade, there has been a debate on how to properly account for their correlations with host galaxy properties. Using the Bayesian hierarchical model UNITY, we simultaneously fit f
or the SN Ia light curve and host galaxy standardization parameters on a set of 103 Sloan Digital Sky Survey II SNe Ia. We investigate the influences of host stellar mass, along with both localized ($r<3$ kpc) and host-integrated average stellar ages, derived from stellar population synthesis modeling. We find that the standardization for the light-curve shape ($alpha$) is correlated with host galaxy standardization terms ($gamma_i$) requiring simultaneous fitting. In addition, we find that these correlations themselves are dependent on host galaxy stellar mass that includes a shift in the color term ($beta$) of $0.8 mathrm{mag}$, only significant at $1.2sigma$ due to the small sample. We find a linear host mass standardization term at the $3.7sigma$ level, that by itself does not significantly improve the precision of an individual SN Ia distance. However, a standardization that uses both stellar mass and average local stellar age is found to be significant at $>3sigma$ in the two-dimensional posterior space. In addition, the unexplained scatter of SNe Ia absolute magnitude post standardization, is reduced from $0.122^{+0.019}_{-0.018}$ to $0.109pm0.017$ mag, or $sim10%$. We do not see similar improvements when using global ages. This combination is consistent with either metallicity or line-of-sight dust affecting the observed luminosity of SNe Ia.
LIGO has detected gravitational waves from massive binary black hole mergers. In order to explain the origin of such massive stellar-mass black holes, extreme metal poor stars including first stars have been invoked. However, black holes do not carry
information of the metallicity. In order to check the metallicity dependence of the black hole formation, we focus on galactic black hole-main sequence binaries (BH-MSs). Using a binary population synthesis method, we find that $gaia$ can detect $sim200-400$ BH-MSs whose metallicity is $zsun$ and $sim70-400$ BH-MSs whose metallicity is $0.1zsun$. With the spectroscopic observation on 4-m class telescopes, we can check the metallicity of BH-MSs. The metallicity dependence of the black hole formation might be checked by the astrometry and spectroscopic observations.
We aim to study how the orbits of galaxies in clusters depend on the prominence of the corresponding central galaxies. We divided our data set of $sim$ 100 clusters and groups into four samples based on their magnitude gap between the two brightest m
embers, $Delta m_{12}$. We then stacked all the systems in each sample, in order to create four stacked clusters, and derive the mass and velocity anisotropy profiles for the four groups of clusters using the MAMPOSSt procedure. Once the mass profile is known, we also obtain the (non parametric) velocity anisotropy profile via the inversion of the Jeans equation. In systems with the largest $Delta m_{12}$, galaxy orbits are prevalently radial, except near the centre, where orbits are isotropic (or tangential when also the central galaxies are considered in the analysis). In the other three samples with smaller $Delta m_{12}$, galaxy orbits are isotropic or only mildly radial. Our study supports the results of numerical simulations that identify radial orbits of galaxies as the cause of an increasing $Delta m_{12}$ in groups.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
