CONNECTION BETWEEN THE CIRCUMGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM OF GALAXIES: RESULTS FROM THE COS-GASS SURVEY
CONNECTION BETWEEN THE CIRCUMGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM OF GALAXIES: RESULTS FROM THE COS-GASS SURVEY
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DOI：
10.1088/0004-637x/813/1/46
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
S. Borthakur;T. Heckman;J. Tumlinson;R. Bordoloi;C. Thom;B. Catinella;D. Schiminovich;R. Davé;G. Kauffmann;S. Moran;A. Saintonge
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作者：
S. Borthakur;T. Heckman;J. Tumlinson;R. Bordoloi;C. Thom;B. Catinella;D. Schiminovich;R. Davé;G. Kauffmann;S. Moran;A. Saintonge
本文介绍了一项探索星际介质(ISM)的性质和性质及其与星际介质(ISM)中原子气体含量之间的关系的研究，该物质由HI21厘米线追踪。我们的样本包括来自GALEX阿雷西博SDSS调查(星系演化探测器/阿雷西博/斯隆数字天空调查)的45个低z(0.026-0.049)星系。在63-231kpc的碰撞参数下，通过吸收背景类恒星天体的光谱来探测它们的CGM。这些光谱是由哈勃太空望远镜上的宇宙起源光谱仪获得的。我们在92%的星系的CGM中探测到了中性氢(Lyα吸收线)。我们发现，由Lyα当量宽度跟踪的CGM的径向轮廓可以按指数形式进行拟合，其标度长度大致等于暗物质晕的维里半径。我们发现视线相对于星系长轴的方向与Lyα当量宽度之间没有关联。环星系气体的速度扩散与ISM中原子气体的速度分布是一致的。我们发现气体分数(M(HI)/M⋆)与经碰撞参数修正的Lyα当量宽度之间有很强的相关性(99.8%置信度)。这比修正的Lyα当量宽度与比星形成率/M⋆之间的相似相关性(97.5%置信度)更强。这些结果暗示了HI盘和CGM之间的物理联系，CGM在尺度上要大一个数量级。这与HI盘被来自CGM的气体吸积所滋养的图景是一致的。
We present a study exploring the nature and properties of the circumgalactic medium (CGM) and its connection to the atomic gas content in the interstellar medium (ISM) of galaxies as traced by the H i 21 cm line. Our sample includes 45 low-z (0.026–0.049) galaxies from the GALEX Arecibo SDSS Survey (Galaxy Evolution Explorer/Arecibo/Sloan Digital Sky Survey). Their CGM was probed via absorption in the spectra of background quasi-stellar objects at impact parameters of 63–231 kpc. The spectra were obtained with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. We detected neutral hydrogen (Lyα absorption lines) in the CGM of 92% of the galaxies. We find that the radial profile of the CGM as traced by the Lyα equivalent width can be fit as an exponential with a scale length of roughly the virial radius of the dark matter halo. We found no correlation between the orientation of the sightline relative to the galaxy’s major axis and the Lyα equivalent width. The velocity spread of the circumgalactic gas is consistent with that seen in the atomic gas in the ISM. We find a strong correlation (99.8% confidence) between the gas fraction (M(H i)/M⋆) and the impact-parameter-corrected Lyα equivalent width. This is stronger than the analogous correlation between corrected Lyα equivalent width and specific star formation rate (SFR)/M⋆ (97.5% confidence). These results imply a physical connection between the H i disk and the CGM, which is on scales an order of magnitude larger. This is consistent with the picture in which the H i disk is nourished by accretion of gas from the CGM.