From star-forming spirals to passive spheroids: integral field spectroscopy of E+A galaxies
From star-forming spirals to passive spheroids: integral field spectroscopy of E+A galaxies
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从恒星形成螺旋到被动球体：E A 星系的积分场光谱
DOI：
10.1111/j.1365-2966.2011.20082.x
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发表时间：
2011
影响因子：
4.8
通讯作者：
Portsmouth
中科院分区：
文献类型：
--
作者：
M. Swinbank;M. Balogh;R. Bower;A. Zabludoff;J. Lucey;S. McGee;C. Miller;R. Nichol;Icc;Durham;Waterloo;Arizona;Michigan.;Portsmouth
我们给出了在z=0.06-0.12的11个E+A星系的三维光谱。这些星系之所以被选中，是因为它们对Hδ的吸收很强，但[O II]λ3727和H发射很弱(或根本不存在)。这一选择表明，最近的一次恒星形成爆发是被触发的，但随后突然终止。我们探索了年轻(≲1Gyr)和老年(≳少数Gyr)恒星种群的空间和光谱特性。利用Hδ当量宽度，我们估计爆发质量一定至少为质量的10%(MBurst≳1010M⊙)，这也与从宽带光谱能量分布推断的恒星形成历史相一致。平均而言，A星覆盖了银河系图像的33%，延伸超过2-15kp2，这表明E+A特征是整个星系的特性，而不是由于种群的不同混合所致。在大约一半的样本中，我们发现A星、星云发射和连续体发射并不在同一位置，这表明最新的恒星是在不同于前形成≲1 Gyr的恒星的地方形成的，并且最近的恒星形成发生在与最古老的恒星群不同的区域。至少有10个星系(91%)的动力学特性将它们归类为“快速旋转星”，其星等、v/σ，λR和凸起与总的比率(B/T)可与具有代表性的局部椭圆和SOS相媲美。我们还发现了A星的空间范围与星系的动力学状态之间的关系，使得最快的旋转体往往拥有最紧凑的A星群体，这为旨在解释较晚类型星系向早期类型转变的模型提供了新的约束。最后，我们表明，在射电(活动星系核，AGN)中探测到的E+A星系的线宽和运动学与非射电源相比没有明显的差异，这表明活动星系核反馈在确定它们的性质方面没有起到明显的作用，和/或它的影响是短暂的。
We present three-dimensional spectroscopy of 11 E+A galaxies at z= 0.06–0.12. These galaxies were selected for their strong Hδ absorption but weak (or non-existent) [O ii] λ3727 and H emission. This selection suggests that a recent burst of star formation was triggered but subsequently abruptly ended. We probe the spatial and spectral properties of both the young (≲1 Gyr) and old (≳few Gyr) stellar populations. Using the Hδ equivalent widths we estimate that the burst masses must have been at least 10 per cent by mass (Mburst≳ 1010 M⊙), which is also consistent with the star formation history inferred from the broad-band spectral energy distributions. On average the A stars cover ∼33 per cent of the galaxy image, extending over 2–15 kpc2, indicating that the characteristic E+A signature is a property of the galaxy as a whole and not due to a heterogeneous mixture of populations. In approximately half of the sample, we find that the A stars, nebular emission and continuum emission are not co-located, suggesting that the newest stars are forming in a different place than those that formed ≲1 Gyr ago, and that recent star formation has occurred in regions distinct from the oldest stellar populations. At least 10 of the galaxies (91 per cent) have dynamics that class them as ‘fast rotators’ with magnitudes, v/σ, λR and bulge-to-total (B/T) ratio comparable to local, representative ellipticals and S0s. We also find a correlation between the spatial extent of the A stars and the dynamical state of the galaxy such that the fastest rotators tend to have the most compact A star populations, providing new constraints on models that aim to explain the transformation of later type galaxies into early types. Finally, we show that there are no obvious differences between the line extents and kinematics of E+A galaxies detected in the radio (active galactic nucleus, AGN) compared to non-radio sources, suggesting that AGN feedback does not play a dramatic role in defining their properties, and/or that its effects are short.
DOI：
10.1111/j.1365-2966.2009.15193.x
发表时间：
2009
影响因子：
4.8
作者：
Balogh M
通讯作者：
Balogh M