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arXiv 0811.4158astro-ph
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AKARI深度测量中的测光红移精度

Photometric redshift accuracy in AKARI Deep Surveys

M. Negrello, S. Serjeant, C. Pearson, T. Takagi, A. Efstathiou, T. Goto, D. Burgarella, W. -S. Jeong, M. Im, H. M. Lee, H. Matsuhara, S. Oyabu, T. Wada, G. White

摘要:

我们调查的光度红移精度实现与AKARI红外数据在深多波段调查,如在北极领域。我们证明,通过红移的多环芳烃和硅酸盐功能到中红外波长窗口覆盖的AKARI是一个有价值的手段来恢复红移的星爆星系。为此,我们从GOODS-North场收集了由Spitzer、ISO和AKARI卫星提供的光谱红移为0.5<~ zspec <~1.5,测光范围为3.6 ~ 24 μ m的~60个星系样本。红外光谱拟合使用合成星系光谱能量分布占星暴和活动核发射。在我们的样本中,约90%的源的红移被恢复,|z光-z光谱|/(1+z_spec)<~ 10%。对不同的模拟光谱进行类似的分析表明,AKARI的红外数据本身就可以提供精确到|z光-z光谱|/(1+z_spec)在z<~2时<~10%(1-sigma)。在更高的红移下,PAH的特征被移到AKARI覆盖的波长范围之外,并且photo-z的估计依赖于不太突出的1.6微米恒星隆起;在这种情况下,(1+z)的准确度约为10- 15%,前提是AGN对红外辐射的贡献是次主导的。我们的技术并不比光学紫外光z更容易产生红移混叠,而且通过增加亚毫米和/或无线电数据,有可能进一步减少这种混叠。

英文摘要:

We investigate the photometric redshift accuracy achievable with the AKARI infrared data in deep multi-band surveys, such as in the North Ecliptic Pole field. We demonstrate that the passage of redshifted policyclic aromatic hydrocarbons and silicate features into the mid-infrared wavelength window covered by AKARI is a valuable means to recover the redshifts of starburst galaxies. To this end we have collected a sample of ~60 galaxies drawn from the GOODS-North Field with spectroscopic redshift 0.5<~z_spec<~1.5 and photometry from 3.6 to 24 micron, provided by the Spitzer, ISO and AKARI satellites. The infrared spectra are fitted using synthetic galaxy Spectral Energy Distributions which account for starburst and active nuclei emission. For ~90% of the sources in our sample the redshift is recovered with an accuracy |z_phot-z_spec|/(1+z_spec)<~10%. A similar analysis performed on different sets of simulated spectra shows that the AKARI infrared data alone can provide photometric redshifts accurate to |z_phot-z_spec|/(1+z_spec)<~10% (1-sigma) at z<~2. At higher redshifts the PAH features are shifted outside the wavelength range covered by AKARI and the photo-z estimates rely on the less prominent 1.6 micron stellar bump; the accuracy achievable in this case on (1+z) is ~10-15%, provided that the AGN contribution to the infrared emission is subdominant. Our technique is no more prone to redshift aliasing than optical-uv photo-z, and it may be possible to reduce this aliasing further with the addition of submillimetre and/or radio data.

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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