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arXiv 0809.4407astro-ph
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光度法辅助光谱提取(PHASE)和SNLS超新星的识别

PHotometry Assisted Spectral Extraction (PHASE) and identification of SNLS supernovae

S. Baumont, C. Balland, P. Astier, J. Guy, D. Hardin, D. A. Howell, C. Lidman, M. Mouchet, R. Pain, N. Regnault

摘要:

目的:我们提出了新的提取和识别技术的超新星(SN)光谱内开发的超新星遗产调查(SNLS)的合作。方法:新的光谱提取方法充分利用了加拿大-法国-夏威夷望远镜(CFHT)发现的光度信息和参考图像,通过跟踪光谱图上超新星和宿主信号的确切位置。当存在时,在深多波段参考图像上测量宿主空间分布,并用于模拟宿主对完整(超新星+宿主)信号的贡献。超新星被建模为宽度等于视宁度的高斯函数。卡方最小化提供2D频谱图的每个像素中的每个分量的通量。对于主超新星分离大于<~ 1像素的情况,这两个分量被分别恢复,与更标准的分析相比,我们不使用光谱模板。这种新的程序允许一个干净的提取超新星分别从主机在约70%的第三年ESO/VLT光谱的SNLS。提出了一种新的超新星鉴别方法。它使用SALT 2分光光度模板来结合光度和光谱数据。一个星系的模板是允许光谱的超新星和主机的单独提取是不可能的。结果:这些新技术已被测试对更多的标准提取和鉴定程序。它们允许在大约80%的情况下进行安全的类型和红移测定。本文用几个样品光谱说明了它们的性能。

英文摘要:

Aim: We present new extraction and identification techniques for supernova (SN) spectra developed within the Supernova Legacy Survey (SNLS) collaboration. Method: The new spectral extraction method takes full advantage of photometric information from the Canada-France-Hawai telescope (CFHT) discovery and reference images by tracing the exact position of the supernova and the host signals on the spectrogram. When present, the host spatial profile is measured on deep multi-band reference images and is used to model the host contribution to the full (supernova + host) signal. The supernova is modelled as a Gaussian function of width equal to the seeing. A chi-square minimisation provides the flux of each component in each pixel of the 2D spectrogram. For a host-supernova separation greater than <~ 1 pixel, the two components are recovered separately and we do not use a spectral template in contrast to more standard analyses. This new procedure permits a clean extraction of the supernova separately from the host in about 70% of the 3rd year ESO/VLT spectra of the SNLS. A new supernova identification method is also proposed. It uses the SALT2 spectrophotometric template to combine the photometric and spectral data. A galaxy template is allowed for spectra for which a separate extraction of the supernova and the host was not possible. Result: These new techniques have been tested against more standard extraction and identification procedures. They permit a secure type and redshift determination in about 80% of cases. The present paper illustrates their performances on a few sample spectra.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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