Kavli Affiliate: Hsiaowen Chen
|Summary:We investigate large-scale gas kinematics in the multiphase circumgalactic medium (CGM) using the observed correlation between line width and column density for H I and O VI absorbers. Leveraging extensive public galaxy survey data at $zlesssim0.1$, we construct a new galaxy sample based on the availability of background QSOs with far-ultraviolet spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE). By combining this FUSE-galaxy sample with literature collections, we find that H I absorbers exhibit a clear inverse correlation between Doppler width and column density over nearly five orders of magnitude in $N_rm HI$, from $N_rm HI approx 10^13rm~cm^-2$ to $N_rm HI approx 10^18rm~cm^-2$, while O VI absorption follows a positive correlation across $N_rm OVIapprox 3times10^13$-$10^15rm~cm^-2$. We develop a model framework to interpret these contrasting trends and show that H I absorbers are best described as systems of approximately constant total column density ($N_rm H$), whereas O VI traces regions of roughly constant spatial density ($n_rm H$ and $n_rm OVI$). Under the latter scenario, the observed $b_rm OVI$-$N_rm OVI$ relation maps directly to a velocity-size relation consistent with a Kolmogorov-like turbulent spectrum. Together, these findings reveal a coherent physical picture in which H I and O VI trace a continuous turbulent cascade spanning more than five orders of magnitude in spatial scale-from cool, photoionized clumps to warm, highly ionized halo gas–with accretion in the halo outskirts likely driving the turbulent energy injection that sustains the multiphase CGM.| Search Query: arXiv Query: search_query=au:”Chen Hsiao-wen”&id_list=&start=0&max_results=10Read More