اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدClustering of supernova Ia host galaxies
262
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
For the first time the cross-correlation between type Ia supernova host galaxies and surrounding field galaxies is measured using the Supernova Legacy Survey sample. Over the z=0.2 to 0.9 redshift range we find that supernova hosts are correlated an average of 60% more strongly than similarly selected field galaxies over the 3-100 arcsec range and about a factor of 3 more strongly below 10 arcsec. The correlation errors are empirically established with a jackknife analysis of the four SNLS fields. The hosts are more correlated than the field at a significance of 99% in the fitted amplitude and slope, with the point-by-point difference of the two correlation functions having a reduced $chi^2$ for 8 degrees of freedom of 4.3, which has a probability of random occurrence of less than 3x10^{-5}. The correlation angle is 1.5+/-0.5 arcsec, which deprojects to a fixed co-moving correlation length of approximately 6.5+/- 2/h mpc. Weighting the field galaxies with the mass and star formation rate supernova frequencies of the simple A+B model produces good agreement with the observed clustering. We conclude that these supernova clustering differences are primarily the expected outcome of the dependence of supernova rates on galaxy masses and stellar populations with their clustering environment.
قيم البحث
اقرأ أيضاً
We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia Supernovae (SNe Ia), sourced from the CSP, CfA, SDSS-II, and SNLS supernova samples, to examine the relationships between SNe Ia and the galaxies that host the
m. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance $rm > 5 sigma$), and decline more rapidly in massive hosts (significance $rm > 9sigma$) and in hosts with low specific star formation rates (significance $rm > 8sigma$). We study the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts, and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter ($rm sigma_{int}=0.08pm0.01$) in luminosity after standardization.
We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory (SNfactory). Combining GALEX UV data with optical and near infrared photometry, we employ stellar populatio
n synthesis techniques to measure SN Ia host galaxy stellar masses, star-formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high precision redshifts, gas-phase metallicities, and Halpha-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from SDSS for stellar masses log(M_*/M_Sun)>8.5 where the relation is well-defined. The star-formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.
We present an analysis of the light curve (LC) decline rates $(Delta m_{15})$ of 407 normal and peculiar supernovae (SNe) Ia and global parameters of their host galaxies. As previously known, there is a significant correlation between the $Delta m_{1
5}$ of normal SNe Ia and global ages (morphologies, colours, masses) of their hosts. On average, those normal SNe Ia that are in galaxies from the Red Sequence (early-type, massive, old hosts) have faster declining LCs in comparison with those from the Blue Cloud (late-type, less massive, younger hosts) of the colour-mass diagram. The observed correlations between the $Delta m_{15}$ of normal SNe Ia and hosts parameters appear to be due to the superposition of at least two distinct populations of faster and slower declining normal SNe Ia from older and younger stellar components. We show, for the first time, that the $Delta m_{15}$ of 91bg- and 91T-like SNe is independent of host morphology and colour. The distribution of hosts on the colour-mass diagram confirms the known tendency for 91bg-like SNe to occur in globally red/old galaxies while 91T-like events prefer blue/younger hosts. On average, the youngest global ages of 02cx-like SNe hosts and their positions in the colour-mass diagram hint that these events likely originate from young population, but they differ from 91T-like events in the LC decline rate. Finally, we discuss the possible explosion channels and present our favoured SN Ia models that have the potential to explain the observed SN-host relations.
We measured high-quality surface brightness fluctuation (SBF) distances for a sample of 63 massive early-type galaxies using the WFC3/IR camera on the Hubble Space Telescope. The median uncertainty on the SBF distance measurements is 0.085 mag, or 3.
9% in distance. Achieving this precision at distances of 50 to 100 Mpc required significant improvements to the SBF calibration and data analysis procedures for WFC3/IR data. Forty-two of the galaxies are from the MASSIVE Galaxy Survey, a complete sample of massive galaxies within ~100 Mpc; the SBF distances for these will be used to improve the estimates of the stellar and central supermassive black hole masses in these galaxies. Twenty-four of the galaxies are Type Ia supernova hosts, useful for calibrating SN Ia distances for early-type galaxies and exploring possible systematic trends in the peak luminosities. Our results demonstrate that the SBF method is a powerful and versatile technique for measuring distances to galaxies with evolved stellar populations out to 100 Mpc and constraining the local value of the Hubble constant.
The Supernova Cosmology Project has conducted the `See Change programme, aimed at discovering and observing high-redshift (1.13 $leq$ z $leq$ 1.75) Type Ia supernovae (SNe Ia). We used multi-filter Hubble Space Telescope (HST) observations of massive
galaxy clusters with sufficient cadence to make the observed SN Ia light curves suitable for a cosmological probe of dark energy at z > 0.5. This See Change sample of SNe Ia with multi-colour light curves will be the largest to date at these redshifts. As part of the See Change programme, we obtained ground-based spectroscopy of each discovered transient and/or its host galaxy. Here we present Very Large Telescope (VLT) spectra of See Change transient host galaxies, deriving their redshifts, and host parameters such as stellar mass and star formation rate. Of the 39 See Change transients/hosts that were observed with the VLT, we successfully determined the redshift for 26, including 15 SNe Ia at z > 0.97. We show that even in passive environments, it is possible to recover secure redshifts for the majority of SN hosts out to z = 1.5. We find that with typical exposure times of 3 - 4 hrs on an 8m-class telescope we can recover ~75% of SN Ia redshifts in the range of 0.97 < z < 1.5. Furthermore, we show that the combination of HST photometry and VLT spectroscopy is able to provide estimates of host galaxy stellar mass that are sufficiently accurate for use in a mass-step correction in the cosmological analysis.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
