arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1003.5329astro-ph.CO
收藏

NGC 5253中心区电离气体与星团相互作用的二维光谱研究

A study of the interplay between ionized gas and star clusters in the central region of NGC 5253 with 2D spectroscopy

A. Monreal-Ibero, J. M. Vilchez, J. R. Walsh, C. Munoz-Tunon

摘要:

简要:本文对NGC 5253中心区进行了详细的二维研究,以描述其中心区~ 210 pc × 130 pc的恒星和电离气体结构以及电离气体的消光分布、物理性质和运动学特征。我们利用光学积分场光谱(IFS)与火焰获得的数据。NGC 5253中电离气体的详细消光图显示,最大的消光与突出的巨HII区域有关。在光学连续谱的峰和消光峰之间存在约0.5”的偏移,这与红外中的发现一致。我们发现恒星的消光比气体少0.33倍。[SII] l 6717/[SII] l 6731图显示电子密度(N_e)梯度从Ha(790 cm ^-3)的发射峰值向外下降,而Ar线比跟踪$N_e~4200 - 6200 cm ^(-3)的区域。根据过量[NII]/Ha推断,被额外氮污染的区域延伸到距离最大污染3.3”(~ 60 pc)的距离,该距离与连续排放峰值偏移~1.5”。沃尔夫-拉叶特徴以不规则的模式分布在较大的区域(~ 100 pc x 100 pc),与年轻的星团有关。我们测量了大部分视场中的He^+丰度,在局部区域中,He^+/H^+的值<~0.0005,这些区域通常与W-R发射或额外氮的区域不一致。线路轮廓很复杂。最多需要三个发射分量来再现它们。其中一个与巨大的HII区有关,呈现超音速宽度,[NII]和[SII]发射线相对于Ha移动了40 km/s。类似地,其中一个窄分量在[NII]线上呈现<~ 20 km/s的偏移。这是第一次,这样的速度偏移的星爆星系的地图已提交。

英文摘要:

ABRIDGED: A detailed 2D study of the central region of NGC5253 has been performed to characterize the stellar and ionized gas structure as well as the extinction distribution, physical properties and kinematics of the ionized gas in the central ~210pc x 130pc. We utilized optical integral field spectroscopy (IFS) data obtained with FLAMES. A detailed extinction map for the ionized gas in NGC5253 shows that the largest extinction is associated with the prominent Giant HII region. There is an offset of ~0.5" between the peak of the optical continuum and the extinction peak in agreement with findings in the infrared. We found that stars suffer less extinction than gas by a factor of 0.33. The [SII]l6717/[SII]l6731 map shows an electron density (N_e) gradient declining from the peak of emission in Ha (790cm^-3) outwards, while the argon line ratio traces areas with $N_e~4200 - 6200cm^(-3). The area polluted with extra nitrogen, as deduced from the excess [NII]/Ha, extends up to distances of 3.3" (~60pc) from the maximum pollution, which is offset by ~1.5" from the peak of continuum emission. Wolf-Rayet features are distributed in an irregular pattern over a larger area (~100pc x 100pc) and associated with young stellar clusters. We measured He^+ abundances over most of the field of view and values of He^++/H^+<~0.0005 in localized areas which do not coincide, in general, with the areas presenting W-R emission or extra nitrogen. The line profiles are complex. Up to three emission components were needed to reproduce them. One of them, associated with the giant HII region, presents supersonic widths and [NII] and [SII] emission lines shifted up to 40km/s with respect to Ha. Similarly, one of the narrow components presents offsets in the [NII] line of <~20km/s. This is the first time that maps with such velocity offsets for a starburst galaxy have been presented.

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。

↑