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arXiv 1004.4816astro-ph.CO
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DiskMass调查。I.概述

The DiskMass Survey. I. Overview

Matthew A. Bershady, Marc A. W. Verheijen, Rob A. Swaters, David R. Andersen, Kyle B. Westfall, Thomas Martinsson

摘要:

我们提出了一个调查的螺旋盘的质量表面密度,在旋转曲线分解突出的不确定性的动机。我们的方法利用积分场光谱测量恒星和气体运动学在近面对星系采样在515,660和860 nm,使用定制的SparsePak和PPak仪器。从UGC中选取的一个两层样本包括146个几乎面对面的星系,B<14.7,盘标度长度在10到20角秒之间,我们已经获得了它们的H-α速度场;还有一个代表性的46个星系子集,我们已经获得了它们的恒星速度和速度色散。根据对现有光度和光谱数据的重新校准,我们发现这些星系的跨度因子L(K)为100(0.03 < L/L(K)* < 3),L(B)/L(K)为8,R波段盘中心表面亮度为10,距离在15 - 200 Mpc之间。该调查是由4-70微米斯皮策IRAC和MIPS测光,地基UBVRIJHK测光,和HI孔径合成成像增强。我们概述了光谱分析协议,用于获得精确和准确的视线恒星速度色散。我们的关键测量是动态盘质量表面密度。恒星形成率和星系盘的运动学和光度规律性也是这项研究的核心成果。巡天的目的是产生足够小的随机和系统误差:(i)证实或反驳中间型盘星系的最大盘假设,(ii)提供远低于当今恒星群体合成模型中不确定性的恒星质光比的绝对校准,(iii)在确定盘星系内部区域暗晕形状方面取得重大进展。

英文摘要:

We present a survey of the mass surface-density of spiral disks, motivated by outstanding uncertainties in rotation-curve decompositions. Our method exploits integral-field spectroscopy to measure stellar and gas kinematics in nearly face-on galaxies sampled at 515, 660, and 860 nm, using the custom-built SparsePak and PPak instruments. A two-tiered sample, selected from the UGC, includes 146 nearly face-on galaxies, with B<14.7 and disk scale-lengths between 10 and 20 arcsec, for which we have obtained H-alpha velocity-fields; and a representative 46-galaxy subset for which we have obtained stellar velocities and velocity dispersions. Based on re-calibration of extant photometric and spectroscopic data, we show these galaxies span factors of 100 in L(K) (0.03 < L/L(K)* < 3), 8 in L(B)/L(K), 10 in R-band disk central surface-brightness, with distances between 15 and 200 Mpc. The survey is augmented by 4-70 micron Spitzer IRAC and MIPS photometry, ground-based UBVRIJHK photometry, and HI aperture-synthesis imaging. We outline the spectroscopic analysis protocol for deriving precise and accurate line-of-sight stellar velocity dispersions. Our key measurement is the dynamical disk-mass surface-density. Star-formation rates and kinematic and photometric regularity of galaxy disks are also central products of the study. The survey is designed to yield random and systematic errors small enough (i) to confirm or disprove the maximum-disk hypothesis for intermediate-type disk galaxies, (ii) to provide an absolute calibration of the stellar mass-to-light ratio well below uncertainties in present-day stellar-population synthesis models, and (iii) to make significant progress in defining the shape of dark halos in the inner regions of disk galaxies.

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