本文介绍了185颗Ia型超新星（SN Ia）的多波段光度测量，共获得11500多个观测结果。这些是在2001年至2008年期间在F。L.哈佛-史密森天体物理中心（Harvard Smithsonian Center for Astrophysics，CfA）这个样本包含了迄今为止发表的最大数量的观测到的和还原的邻近Ia超新星（z < 0.08）。它使附近的样本增加了一倍多，使超新星Ia宇宙学达到了系统不确定性占主导地位的地步。我们的自然系统测光的精度为0.02等或更好的BVRIr 'i'和大约0.04等，在U的点亮度超过17.5等。我们还估计了一个系统的不确定度为0.03等，在我们的超新星Ia标准系统BVRIr 'i'测光和0.07等的U。我们的标准系统测光与已公布的Ia型超新星光变曲线和比较星的比较，在相同的SN，在大多数情况下，在百分之几等的水平上显示协议。我们发现1991 bg类超新星Ia在它们的颜色和光变曲线形状/光度关系上与其他超新星Ia有足够的区别，因此它们应该在光变曲线/距离拟合训练样本中单独对待。CfA 3样本将有助于开发更好的光变曲线/距离拟合器，特别是在已经获得近红外测光的几十个案例中，并且可以帮助从内在超新星颜色中解开主星系变红，减少由于尘埃导致的SN Ia距离的系统不确定性。
英文摘要：
We present multi-band photometry of 185 type-Ia supernovae (SN Ia), with over 11500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains the largest number of homogeneously-observed and reduced nearby SN Ia (z < 0.08) published to date. It more than doubles the nearby sample, bringing SN Ia cosmology to the point where systematic uncertainties dominate. Our natural system photometry has a precision of 0.02 mag or better in BVRIr'i' and roughly 0.04 mag in U for points brighter than 17.5 mag. We also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system BVRIr'i' photometry and 0.07 mag for U. Comparisons of our standard system photometry with published SN Ia light curves and comparison stars, where available for the same SN, reveal agreement at the level of a few hundredths mag in most cases. We find that 1991bg-like SN Ia are sufficiently distinct from other SN Ia in their color and light-curve-shape/luminosity relation that they should be treated separately in light-curve/distance fitter training samples. The CfA3 sample will contribute to the development of better light-curve/distance fitters, particularly in the few dozen cases where near-infrared photometry has been obtained and, together, can help disentangle host-galaxy reddening from intrinsic supernova color, reducing the systematic uncertainty in SN Ia distances due to dust.
We present bolometric light curves constructed from multi-wavelength photometry of Type Ia supernovae (SNe Ia) from the Carnegie Supernova Project and the CfA Supernova Group, using near-infrared observations to provide robust constraints on host galaxy dust extinction. This set of light curves form a well-measured reference set for comparison with theoretical models. Ejected mass and synthesized $^{56}$Ni mass are inferred for each SN Ia from its bolometric light curve using a semi-analytic Bayesian light curve model, and fitting formulae provided in terms of light curve width parameters from…
We construct and train an artificial neural network called the back-propagation neural network to describe the evolution of the type Ia supernova spectrum by using the data from the CfA Supernova Program. This network method has many attractive features, and one of them is that the constructed model is differentiable. Benefitting from this, we calculate the absorption velocity and its variation. The model we constructed can well describe not only the spectrum of SNe Ia with wavelength range from $3500Å$ to $8000Å$, but also the light-curve evolution with phase time from $-15$ to $50$ with diff…
We assess the robustness of the two highest rungs of the "cosmic distance ladder" for Type Ia supernovae and the determination of the Hubble-Lemaître constant. In this analysis, we hold fixed Rung 1 as the distance to the LMC determined to 1 % using Detached Eclipsing Binary stars. For Rung 2 we analyze two methods, the TRGB and Cepheid distances for the luminosity calibration of Type Ia supernovae in nearby galaxies. For Rung 3 we analyze various modern digital supernova samples in the Hubble flow, such as the Calán-Tololo, CfA, CSP, and Supercal datasets. This metadata analysis demonstrates …
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 them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance $\rm > 5 σ$), and decline more rapidly in massive hosts (significance $\rm > 9σ$) and in hosts with low specific star formation rates (significance $\rm > 8σ$). We study the varia…
We present a revised SALT2 surface (`SALT2-2021') for fitting the light curves of Type Ia supernovae (SNe Ia), which incorporates new measurements of zero-point calibration offsets and Milky Way extinction. The most notable change in the new surface occurs in the UV region. This new surface alters the distance measurements of SNe~Ia, which can be used to investigate the nature of dark energy by probing the expansion history of the Universe. Using the revised SALT2 surface on public data from the first three years of the Dark Energy Survey Supernova Program (combined with an external low-$z$ SN…
Secondary Parameters of Type Ia Supernova Light Curves
在Las Campanas天文台对当地Ia型超新星（SNe Ia）的$B$和$V$光变曲线进行的高质量观测表明，具有相同亮度衰减或拉伸的SNe Ia在最大光之后30天可能有系统的和独立的偏差< 5 days before and at times >。这表明存在两个独立的次要参数，除了亮度下降的关系控制的形状的超新星Ia光变曲线。伸展。的差异是一致的形态的时间依赖性和大小与预测模型内的延迟爆炸的情况。二次参数可以反映两个独立的物理效应所造成的祖和吸积率的变化，并链接的LC形状的变化与内在的，绝对的亮度。
Type Ia supernovae have light curves that have widths and magnitudes that can be used for testing cosmologies and they provide one of the few direct measurements of time dilation. It is shown that the standard analysis that calibrates the light curve against a rest-frame average (such as SALT2) removes all the cosmological information from the calibrated light curves. Consequently type Ia supernovae calibrated with these methods cannot be used to investigate cosmology. The major evidence that supports the hypothesis of a static universe is that the measurements of the widths of the raw light c…
We present detailed investigation of a specific $i$-band light-curve feature in Type Ia supernovae (SNe Ia) using the rapid cadence and high signal-to-noise ratio light-curves obtained by the Carnegie Supernova Project. The feature is present in most SNe Ia and emerges a few days after the $i$-band maximum. It is an abrupt change in curvature in the light-curve over a few days and appears as a flattening in mild cases and a strong downward concave shape, or a "kink", in the most extreme cases. We computed the second derivatives of Gaussian Process interpolations to study 54 rapid-cadence light…
We have analyzed multi-band light curves of 328 intermediate redshift (0.05 <= z < 0.24) type Ia supernovae (SNe Ia) observed by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II SN Survey). The multi-band light curves were parameterized by using the Multi-band Stretch Method, which can simply parameterize light curve shapes and peak brightness without dust extinction models. We found that most of the SNe Ia which appeared in red host galaxies (u - r > 2.5) don't have a broad light curve width and the SNe Ia which appeared in blue host galaxies (u - r < 2.0) have a variety of light cur…
Type II Supernovae: Model Light Curves and Standard Candle Relationships
II型超新星爆炸模型的调查已经进行，以确定它们的光变曲线和光谱如何随它们的质量，金属丰度和爆炸能量而变化。前超新星模型取自最近对太阳金属丰度下大质量恒星演化的调查，并辅以太阳下金属丰度的新计算。爆炸是由一个活塞附近的铁芯的边缘的运动模拟和由此产生的光变曲线和光谱计算使用全多波长辐射输运。公式的开发，描述了大约如何模型观测（光变曲线光度和持续时间）规模与祖质量，爆炸能量，和放射性核合成。与观测数据的比较表明，典型超新星的爆炸能量（用无穷远处的动能来衡量）相差近一个数量级--从0.5到4.0 x 10^51尔格，典型值约为0.9 x 10^51尔格。尽管有很大的变化，模型表现出紧密的光度和膨胀速度之间的关系，类似于以前采用的经验，使SNe IIP标准化蜡烛。这种关系可以用超新星包层中氢复合的简单行为来解释，但是我们发现对祖先金属丰度和质量的敏感性可能导致系统误差。光变曲线光度、持续时间和颜色之间的其他相关性可能使SNe IIP能够仅使用光度数据获得精确到约20%的距离。
We discovered two transient events in the Kepler field with light curves that strongly suggest they are type II-P supernovae. Using the fast cadence of the Kepler observations we precisely estimate the rise time to maximum for KSN2011a and KSN2011d as 10.5$\pm 0.4$ and 13.3$\pm 0.4$ rest-frame days respectively. Based on fits to idealized analytic models, we find the progenitor radius of KSN2011a (280$\pm 20$ R$_\odot$) to be significantly smaller than that for KSN2011d (490$\pm 20$ R$_\odot$) but both have similar explosion energies of 2.0$\pm 0.3\times 10^{51}$ erg. The rising light curve of…
The spectral energy distribution (SED) sequence for type Ia supernovae (SN Ia) is modeled by an artificial neural network. The SN Ia luminosity is characterized as a function of phase, wavelength, a color parameter and a decline rate parameter. After training and testing the neural network, the SED sequence could give both the spectrum with wavelength range from 3000Å~to 8000Å~ and the light curve with phase from 20 days before to 50 days after the maximum luminosity for the supernovae with different colors and decline rates. Therefore, we call this the Artificial Neural Network Spectral Light…
The LaSilla/QUEST Variability Survey (LSQ) and the Carnegie Supernova Project (CSP II) are collaborating to discover and obtain photometric light curves for a large sample of low redshift (z < 0.1) Type Ia supernovae. The supernovae are discovered in the LSQ survey using the 1 m ESO Schmidt telescope at the La Silla Observatory with the 10 square degree QUEST camera. The follow-up photometric observations are carried out using the 1 m Swope telescope and the 2.5 m du Pont telescopes at the Las Campanas Observatory. This paper describes the survey, discusses the methods of analyzing the data an…
With growing data from ongoing and future supernova surveys it is possible to empirically quantify the shapes of SNIa light curves in more detail, and to quantitatively relate the shape parameters with the intrinsic properties of SNIa. Building such relationship is critical in controlling systematic errors associated with supernova cosmology. Based on a collection of well-observed SNIa samples accumulated in the past years, we construct an empirical SNIa light curve model using a statistical method called the functional principal component analysis (FPCA) for sparse and irregularly sampled fun…
We examine the light curve parameters of 97 nearby Type Ia supernovae in the ultraviolet and optical using observations from the Swift Ultra-Violet/Optical Telescope. Our light curve models used a linear combinations of templates, which were based on Functional Principal Component Analysis of the optical photometry of SNe Ia. The weights for each principal component used in the fit capture certain aspects of the light curve properties. We find that there is little difference in the overall variability of principal component scores across filters. We also find correlations between certain filte…
