Estimating Fixed-Frame Galaxy Magnitudes in the Sloan Digital Sky Survey
Estimating Fixed-Frame Galaxy Magnitudes in the Sloan Digital Sky Survey
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DOI：
10.1086/342935
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发表时间：
2002-05
期刊：
影响因子：
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通讯作者：
M. Blanton;J. Brinkmann;I. Csabai;M. Doi;D. Eisenstein;M. Fukugita;J. Gunn;D. Hogg;D. Schlegel-D.
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文献类型：
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作者：
M. Blanton;J. Brinkmann;I. Csabai;M. Doi;D. Eisenstein;M. Fukugita;J. Gunn;D. Hogg;D. Schlegel-D.
对处于不同红移的星系的流量进行宽带测量，可以测量静止星系光谱的不同区域。某些天文学问题，如星系光度函数的演化，需要将这些与红移有关的星等转换为与红移无关的量。为了准备解决这些在后续论文中详细研究的天文问题，我们在斯隆数字巡天(SDSS)的光学观测背景下，将光谱能量分布(SED)拟合到宽带光度观测中。四个光谱模板的线性组合可以重现所有星系的五个SDSS星等，达到光度测量的精度。在适当的坐标系中表示，系数乘以模板的轨迹是平面的，并且实际上几乎是线性的。所得到的重建的SED可用于恢复红移范围内的固定帧幅度。这个过程产生了一致的结果，在这个意义上，在每个样本中，相似类型星系的本征颜色几乎是不变的，但红移。我们将我们的结果与SDSS的更简单的插值法和星系分光光度法进行了比较。产生这些结果的软件是公开可用的，很容易被改编成处理广泛的星系观测。
Broadband measurements of flux for galaxies at different redshifts measure different regions of the rest-frame galaxy spectrum. Certain astronomical questions, such as the evolution of the luminosity function of galaxies, require transforming these inherently redshift-dependent magnitudes into redshift-independent quantities. To prepare to address these astronomical questions, investigated in detail in subsequent papers, we fit spectral energy distributions (SEDs) to broadband photometric observations in the context of the optical observations of the Sloan Digital Sky Survey (SDSS). Linear combinations of four spectral templates can reproduce the five SDSS magnitudes of all galaxies to the precision of the photometry. Expressed in the appropriate coordinate system, the locus of the coefficients multiplying the templates is planar and, in fact, nearly linear. The resulting reconstructed SEDs can be used to recover fixed-frame magnitudes over a range of redshifts. This process yields consistent results in the sense that, within each sample, the intrinsic colors of similar type galaxies are nearly constant with redshift. We compare our results with simpler interpolation methods and galaxy spectrophotometry from the SDSS. The software that generates these results is publicly available and easily adapted to handle a wide range of galaxy observations.