LUMINOSITY FUNCTIONS OF TYPE Ia SUPERNOVAE AND THEIR HOST GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY
LUMINOSITY FUNCTIONS OF TYPE Ia SUPERNOVAE AND THEIR HOST GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY
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DOI：
10.1088/0004-6256/139/1/39
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发表时间：
2009-05
期刊：
影响因子：
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通讯作者：
N. Yasuda;M. Fukugita
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文献类型：
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作者：
N. Yasuda;M. Fukugita
利用斯隆数字巡天(SDSS)-II超新星巡天在南赤道300度带观测到的137颗0.05≥z≤0.3的Ia型低红移超新星（SNe Ia）样本，推导了Ia型低红移超新星及其宿主星系在g、r、i波段的光度函数。我们发现Ia型超新星宿主星系的LF与一般场中星系的LF匹配得很好，这表明Ia型超新星的出现并不有利于特定类型的星系，而是主要与星系的光度成正比。SNe速率随宿主星系颜色的变化而变化的证据很弱。唯一指出SN率与恒星形成活动可能相关的证据是，晚型星系的SN率比早型星系高31%±35%。在我们的低红移样品中，Ia型SN率与恒星形成活动成正比的分量在综合SN率中并不明显，而我们的观测结果与目前的双分量模型是兼容的。样本中包含8个Ia型超新星，它们的宿主星系没有被确定，但它们的出现与它们在调查之外的低亮度星系中出现的情况一致。Ia型超新星的LF近似为高斯分布，半最大值时的全宽度为σ = 0.24等或光度为1.67。如果消光与变红之比RV低于银河系的特征值，并且根据光曲线形状对光度进行校正，则高斯分布变得更紧。平均色差为≈0.07等，明显小于预期的场星系变红。这种颜色过剩并不随超新星距离宿主星系中心至15kpc的距离而变化。这表明，颜色过剩的主要部分似乎是内在的或在SNe的直接环境中产生的变红，而不是宿主星系的星际变红，而且SNe Ia的大部分发生在相对无尘的环境中。
The sample of 137 low-redshift type Ia supernovae (SNe Ia) with 0.05 ⩽ z ⩽ 0.3 obtained from the Sloan Digital Sky Survey (SDSS)-II supernova survey for the southern equatorial stripe of 300 deg2 is used to derive the luminosity functions (LFs) of SNe Ia and of their host galaxies in the g, r, i passbands. We show that the LF of SNe Ia host galaxies matches well with that of galaxies in the general field, suggesting that the occurrence of SNe Ia does not favor a particular type of galaxy but is predominantly proportional to the luminosity of galaxies. The evidence is weak that the SNe rate varies with the color of host galaxies. The only evidence that points to possible correlation between the SN rate and star formation activity is that the SN rate in late-type galaxies is higher than that in early-type galaxies by 31% ± 35%. In our low-redshift sample, the component of type Ia SN rate that is proportional to star formation activity is not evident in the integrated SN rate, while our observation is compatible with the current two-component models. The sample contains eight SNe Ia whose host galaxies were not identified, but it is shown that their occurrence is consistent with them occurring in low-luminous galaxies beyond the survey. The LF of SNe Ia is approximately Gaussian with the full width at half-maximum being a factor of σ = 0.24 mag or 1.67 in luminosity. The Gaussian distribution becomes tighter if the ratio of extinction to reddening, RV, is lower than the characteristic value for the Milky Way and if luminosity is corrected for the light-curve shape. The average color excess is ≈0.07 mag, which is significantly smaller than reddening expected for field galaxies. This color excess does not vary with the distance of the SNe from the center of the host galaxy to 15 kpc. This suggests that the major part of the color excess appears to be either intrinsic or reddening that arises in the immediate environment of SNe, rather than interstellar reddening in host galaxies, and most of SNe Ia take place in a relatively dust-free environment.