研究成果・発表論文

Statistical properties of diffuse Ly\ensuremathα haloes around star-forming galaxies at z ̃ 2

Momose, Rieko,   Ouchi, Masami,   Nakajima, Kimihiko,   Ono, Yoshiaki,   Shibuya, Takatoshi,   Shimasaku, Kazuhiro,   Yuma, Suraphong,   Mori, Masao,   & Umemura, Masayuki


要旨
We present statistical properties of diffuse Ly\ensuremathα haloes (LAHs) around high-z star-forming galaxies with large Subaru samples of Ly\ensuremathα emitters (LAEs) at z = 2.2. We make subsamples defined by the physical quantities of LAEs' central Ly\ensuremathα luminosities, ultraviolet (UV) magnitudes, Ly\ensuremathα equivalent widths, and UV slopes, and investigate LAHs' radial surface brightness (SB) profiles and scale lengths r$_n$ as a function of these physical quantities. We find that there exist prominent LAHs around LAEs with faint Ly\ensuremathα luminosities, bright UV luminosities, and small Ly\ensuremathα equivalent widths in cumulative radial Ly\ensuremathα SB profiles. We confirm this trend with the anticorrelation between r$_n$ and Ly\ensuremathα luminosities (equivalent widths) based on the Spearman's rank correlation coefficient that is \ensuremathh̊o = -0.9 (-0.7) corresponding to the 96 per cent (93 per cent) confidence level, although the correlation between r$_n$ and UV magnitudes is not clearly found in the rank correlation coefficient. Our results suggest that LAEs with properties similar to typical Lyman-break galaxies (with faint Ly\ensuremathα luminosities and small equivalent widths) possess more prominent LAHs. We investigate scenarios for the major physical origins of LAHs with our results. Because we find relatively small Ly\ensuremathα equivalent widths up to 77 \Å in LAHs that include LAEs' central components, these results suggest that the cold stream scenario is not preferred. There remain two possible scenarios of Ly\ensuremathα scattering in circumgalactic medium and satellite galaxies that cannot be tested with our observational data.




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