%0 Generic %1 momose2014diffuse %A Momose, Rieko %A Ouchi, Masami %A Nakajima, Kimihiko %A Ono, Yoshiaki %A Shibuya, Takatoshi %A Shimasaku, Kazuhiro %A Yuma, Suraphong %A Mori, Masao %A Umemura, Masayuki %D 2014 %K emission halos lya %T Diffuse Ly$\alpha$ Halos around Galaxies at $z=2.2-6.6$: Implications for Galaxy Formation and Cosmic Reionization %U http://arxiv.org/abs/1403.0732 %X We present diffuse Ly$\alpha$ halos (LAHs) identified in the composite Subaru narrowband images of $100-3600 $ Ly$\alpha$ emitters (LAEs) at $z=2.2$, $3.1$, $3.7$, $5.7$, and $6.6$. First, we carefully examine potential artifacts mimicking LAHs that include a large-scale point-spread function (PSF) made by instrumental and atmospheric effects. Based on our critical test with composite images of non-LAE samples whose narrowband-magnitude and source-size distributions are the same as our LAE samples, we confirm that no artifacts can produce a diffuse extended feature similar to our LAHs. After this test, we measure the scale lengths of exponential profile for the LAHs estimated from our $z=2.2-6.6$ LAE samples of $L_Ly\alpha210^42$ erg s$^-1$. We obtain the scale lengths of $5-10$ kpc at $z=2.2-5.7$, and find no evolution of scale lengths in this redshift range beyond our measurement uncertainties. Combining this result and the previously-known UV-continuum size evolution, we infer that the ratio of LAH to UV-continuum sizes is nearly constant at $z=2.2-5.7$. On the other hand, the scale length of our $z=6.6$ LAH is larger than $5-10$ kpc, and there is a hint that the scale lengths of LAHs would increase from $z=5.7$ to $6.6$. This may be a signature of increasing fraction of neutral hydrogen scattering Ly\alpha$ photons, due to cosmic reionization, although larger data are needed for a definitive conclusion.

@misc{momose2014diffuse, abstract = {We present diffuse Ly$\alpha$ halos (LAHs) identified in the composite Subaru narrowband images of $100-3600 $ Ly$\alpha$ emitters (LAEs) at $z=2.2$, $3.1$, $3.7$, $5.7$, and $6.6$. First, we carefully examine potential artifacts mimicking LAHs that include a large-scale point-spread function (PSF) made by instrumental and atmospheric effects. Based on our critical test with composite images of non-LAE samples whose narrowband-magnitude and source-size distributions are the same as our LAE samples, we confirm that no artifacts can produce a diffuse extended feature similar to our LAHs. After this test, we measure the scale lengths of exponential profile for the LAHs estimated from our $z=2.2-6.6$ LAE samples of $L_{\rm Ly\alpha}\gtrsim 2\times 10^{42}$ erg s$^{-1}$. We obtain the scale lengths of $\simeq 5-10$ kpc at $z=2.2-5.7$, and find no evolution of scale lengths in this redshift range beyond our measurement uncertainties. Combining this result and the previously-known UV-continuum size evolution, we infer that the ratio of LAH to UV-continuum sizes is nearly constant at $z=2.2-5.7$. On the other hand, the scale length of our $z=6.6$ LAH is larger than $5-10$ kpc, and there is a hint that the scale lengths of LAHs would increase from $z=5.7$ to $6.6$. This may be a signature of increasing fraction of neutral hydrogen scattering Ly\alpha$ photons, due to cosmic reionization, although larger data are needed for a definitive conclusion.}, added-at = {2014-03-05T09:49:32.000+0100}, author = {Momose, Rieko and Ouchi, Masami and Nakajima, Kimihiko and Ono, Yoshiaki and Shibuya, Takatoshi and Shimasaku, Kazuhiro and Yuma, Suraphong and Mori, Masao and Umemura, Masayuki}, biburl = {https://www.bibsonomy.org/bibtex/28970d1cda6c809279ca6ea7446283f18/miki}, description = {[1403.0732] Diffuse Ly$\alpha$ Halos around Galaxies at $z=2.2-6.6$: Implications for Galaxy Formation and Cosmic Reionization}, interhash = {f8e0866f64c466a2aa5967571fc72c3e}, intrahash = {8970d1cda6c809279ca6ea7446283f18}, keywords = {emission halos lya}, note = {cite arxiv:1403.0732Comment: 11 pages, 9 figures, 1 table. Submitted to MNRAS}, timestamp = {2014-03-05T09:49:32.000+0100}, title = {Diffuse Ly$\alpha$ Halos around Galaxies at $z=2.2-6.6$: Implications for Galaxy Formation and Cosmic Reionization}, url = {http://arxiv.org/abs/1403.0732}, year = 2014 }