Feedback in the Local Lyman-break Galaxy Analog Haro 11 as Probed by Far-Ultraviolet and X-Ray Observations
Feedback in the Local Lyman-break Galaxy Analog Haro 11 as Probed by Far-Ultraviolet and X-Ray Observations
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通过远紫外线和 X 射线观测探测本地莱曼断裂星系模拟 Haro 11 中的反馈
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发表时间：
2007
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通讯作者：
A. Ptak
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作者：
J. Grimes;T. Heckman;D. Strickland;W. Dixon;K. Sembach;R. Overzier;C. Hoopes;A. Aloisi;A. Ptak
我们重新分析了FUSE观测数据，获得了哈洛11的Chandra观测结果。哈罗11是一个本地（DL = 88 Mpc）紫外发光星系。哈洛11的远紫外光度（1010.3 L）、紫外表面亮度（109.4 L/kpc-2）、星星形成率（SFR）和金属丰度与莱曼破裂星系（LBG）相似。我们发现，哈洛11具有扩展的软热（kT~0.68 keV）X射线发射的亮度和大小与物理性质（例如，SFR，恒星质量）的宿主星系。相对于太阳丰度，α/Fe比值增加到~4，表明超新星有显著的富集作用。这些结果与超新星驱动的外流和周围物质之间的冲击产生的X射线发射一致。远紫外（FUV）光谱显示出类似于LBG光谱中观察到的强吸收线。一个蓝移的吸收分量被确定为在~200 - 280 km s-1流出的风。在T~105.5K，还观测到日冕气体的主要冷却机制--OVI λ λ 1032、1038发射。如果与外流有关，O VI发射的光度表明超新星和太阳风的总机械能的20%被辐射出去。这意味着通过OVI的辐射冷却不会显著抑制流出气体的生长。与Bergvall及其同事的发现相反，我们在哈洛11中没有发现令人信服的莱曼连续体泄漏的证据。我们的结论是，风并没有创造一个"隧道"，允许逃逸的一个显着的部分莱曼连续光子，并放置一个限制的逃逸分数fesc的2%。总的来说，哈洛11和以前观察到的LBG类似物VV 114都为高红移LBG的X射线和FUV特性提供了宝贵的见解。
We have reanalyzed FUSE data and obtained new Chandra observations of Haro 11, a local (DL = 88 Mpc) UV luminous galaxy. Haro 11 has a far-UV luminosity (1010.3 L☉), UV surface brightness (109.4 L☉ kpc-2), star formation rate (SFR), and metallicity similar to those observed in Lyman-break galaxies (LBGs). We show that Haro 11 has extended soft thermal (kT ~ 0.68 keV) X-ray emission of a luminosity and size which scales with the physical properties (e.g., SFR, stellar mass) of the host galaxy. An enhanced α/Fe ratio of ~4 relative to solar abundance suggests significant supernova enrichment. These results are consistent with the X-ray emission being produced in a shock between a supernova-driven outflow and the ambient material. The far-ultraviolet (FUV) spectra show strong absorption lines similar to those observed in LBG spectra. A blueshifted absorption component is identified as a wind outflowing at ~200-280 km s-1. O VI λλ1032,1038 emission, the dominant cooling mechanism for coronal gas at T ~ 105.5 K, is also observed. If associated with the outflow, the luminosity of the O VI emission suggests that ≲20% of the total mechanical energy from the supernovae and solar winds is being radiated away. This implies that radiative cooling through O VI is not significantly inhibiting the growth of the outflowing gas. In contradiction to the findings of Bergvall and coworkers, we find no convincing evidence of Lyman continuum leakage in Haro 11. We conclude that the wind has not created a "tunnel" allowing the escape of a significant fraction of Lyman continuum photons, and place a limit on the escape fraction of fesc ≲ 2%. Overall, both Haro 11 and a previously observed LBG analog, VV 114, provide invaluable insight into the X-ray and FUV properties of high-redshift LBGs.