%0 Generic %1 Malhotra2011 %A Malhotra, Sangeeta %A Rhoads, James E. %A Finkelstein, Steven L. %A Hathi, Nimish %A Nilsson, Kim %A McLinden, Emily %A Pirzkal, Norbert %D 2011 %K lbg size %T Sizing up Lyman-alpha and Lyman Break Galaxies %U http://arxiv.org/abs/1106.2816 %X We show that populations of high redshift galaxies grow more luminous as they grow in linear size. This is because the brightness per unit area has a distinct upper limit due to the self-regulating nature of star-formation. As a corollary, we show that the observed increase in characteristic luminosity of Lyman Break Galaxies (L*) with time can be explained by their increase in size, which scales as 1/H(z). In contrast, Lyman-alpha selected galaxies have a characteristic, constant, small size between redshift z=2.25 and 6.5. Coupled with a characteristic surface brightness, this can explain their non-evolving ultraviolet continuum luminosity function. This compact physical size seems to be a critical determining factor in whether a galaxy will show Lyman-alpha emission. We base these conclusions on new size measurements for a sample of about 170 Lyman-alpha selected galaxies with Hubble Space Telescope broad-band imaging, over the redshift range 2.25 < z < 6. We combine these with a similar number of Lyman-alpha selected galaxies with half-light radii from the literature, and derive surface brightnesses for the entire combined sample.

@misc{Malhotra2011, abstract = { We show that populations of high redshift galaxies grow more luminous as they grow in linear size. This is because the brightness per unit area has a distinct upper limit due to the self-regulating nature of star-formation. As a corollary, we show that the observed increase in characteristic luminosity of Lyman Break Galaxies (L*) with time can be explained by their increase in size, which scales as 1/H(z). In contrast, Lyman-alpha selected galaxies have a characteristic, constant, small size between redshift z=2.25 and 6.5. Coupled with a characteristic surface brightness, this can explain their non-evolving ultraviolet continuum luminosity function. This compact physical size seems to be a critical determining factor in whether a galaxy will show Lyman-alpha emission. We base these conclusions on new size measurements for a sample of about 170 Lyman-alpha selected galaxies with Hubble Space Telescope broad-band imaging, over the redshift range 2.25 < z < 6. We combine these with a similar number of Lyman-alpha selected galaxies with half-light radii from the literature, and derive surface brightnesses for the entire combined sample. }, added-at = {2011-06-16T18:27:13.000+0200}, author = {Malhotra, Sangeeta and Rhoads, James E. and Finkelstein, Steven L. and Hathi, Nimish and Nilsson, Kim and McLinden, Emily and Pirzkal, Norbert}, biburl = {https://www.bibsonomy.org/bibtex/27ffac529ebd4806ed15cdbf8cec5eca3/miki}, description = {[1106.2816] Sizing up Lyman-alpha and Lyman Break Galaxies}, interhash = {f9e10e9f5a5190c67e33b12b3702208c}, intrahash = {7ffac529ebd4806ed15cdbf8cec5eca3}, keywords = {lbg size}, note = {cite arxiv:1106.2816Comment: Submitted to ApJ letters, comments welcome}, timestamp = {2011-06-16T18:27:13.000+0200}, title = {Sizing up Lyman-alpha and Lyman Break Galaxies}, url = {http://arxiv.org/abs/1106.2816}, year = 2011 }