首页> 外文期刊>The Astrophysical journal >VII?Zw?403: H I STRUCTURE IN A BLUE COMPACT DWARF GALAXY
【24h】

VII?Zw?403: H I STRUCTURE IN A BLUE COMPACT DWARF GALAXY

机译:VII Zw 403:H I在蓝色紧凑矮星状星系中的结构

获取原文
           

摘要

We present optical (UBVJ), ultraviolet (FUV, NUV), and high-resolution atomic hydrogen (H I) observations of the nearby blue compact dwarf (BCD), VII?Zw?403. We find that VII?Zw?403 has a relatively high H I mass-to-light ratio for a BCD. The rotation velocity is nominally 10-15?km?s–1, but rises to ~20?km?s–1 after correction for the ~8-10?km?s–1 random motions present in the gas. The velocity field is complex, including a variation in the position angle of the major axis going from the northeast to the southwest parts of the galaxy. Our high-resolution H I maps reveal structure in the central gas, including a large, low-density H I depression or hole between the southern and northern halves of the galaxy, coincident with an unresolved X-ray source. Although interactions have been proposed as the triggering mechanism for the vigorous star formation occurring in BCDs, VII?Zw?403 does not seem to have been tidally triggered by an external interaction, as we have found no nearby possible perturbers. It also does not appear to fall in the set of galaxies that exhibit a strong central mass density concentration, as its optical scale length is large in comparison to similar systems. However, there are some features that are compatible with an accretion event: optical/H I axis misalignment, a change in position angle of the kinematic axis, and a complex velocity field.
机译:我们介绍了附近蓝色紧缩矮星(BCD)VII?Zw?403的光学(UBVJ),紫外线(FUV,NUV)和高分辨率原子氢(HI)观测结果。我们发现,对于BCD,VII Zw 403具有较高的H I质光比。旋转速度名义上为10-15?km?s–1,但在校正了气体中存在的〜8-10?km?s–1随机运动后,上升到了〜20?km?s-1。速度场是复杂的,包括从银河系东北到西南的主轴位置角的变化。我们的高分辨率H I图揭示了中心气体中的结构,包括星系的南半部和北半部之间的一个大的低密度H I凹陷或孔,与一个未解析的X射线源相吻合。尽管已经提出相互作用是发生在BCD中剧烈的恒星形成的触发机制,但VII?Zw?403似乎并没有被外部相互作用以潮汐方式触发,因为我们没有发现附近可能存在干扰。由于它的光学标尺长度比类似系统大,因此它似乎也不会落入显示出强大的中心质量密度浓度的星系。但是,有些特征与吸积事件兼容:光学/ HI轴未对准,运动轴位置角的变化以及复杂的速度场。
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号