%0 Generic %1 whitaker2015galaxy %A Whitaker, Katherine E. %A Franx, Marijn %A Bezanson, Rachel %A Brammer, Gabriel B. %A van Dokkum, Pieter G. %A Kriek, Mariska T. %A Labbe, Ivo %A Leja, Joel %A Momcheva, Ivelina G. %A Nelson, Erica J. %A Rigby, Jane R. %A Rix, Hans-Walter %A Skelton, Rosalind E. %A van der Wel, Arjen %A Wuyts, Stijn %D 2015 %K formation galaxy star structure %T Galaxy Structure as a Driver of the Star Formation Sequence Slope and Scatter %U http://arxiv.org/abs/1508.04771 %X It is well established that (1) star-forming galaxies follow a relation between their star formation rate (SFR) and stellar mass (M$_\star$), the "star-formation sequence", and (2) the SFRs of galaxies correlate with their structure, where star-forming galaxies are less concentrated than quiescent galaxies at fixed mass. Here, we consider whether the scatter and slope of the star-formation sequence is correlated with systematic variations in the Sersic indices, $n$, of galaxies across the SFR-M$_\star$ plane. We use a mass-complete sample of 23,848 galaxies at $0.5<z<2.5$ selected from the 3D-HST photometric catalogs. Galaxy light profiles parameterized by $n$ are based on Hubble Space Telescope CANDELS near-infrared imaging. We use a single SFR indicator empirically-calibrated from stacks of Spitzer/MIPS 24$\mu$m imaging, adding the unobscured and obscured star formation. We find that the scatter of the star-formation sequence is related in part to galaxy structure; the scatter due to variations in $n$ at fixed mass for star-forming galaxies ranges from 0.14$\pm$0.02 dex at $z\sim2$ to 0.30$\pm$0.04 dex at $z<1$. While the slope of the log(SFR)-log(M$_\star$) relation is of order unity for disk-like galaxies, galaxies with $n>2$ (implying more dominant bulges) have significantly lower SFR/M$_\star$ than the main ridgeline of the star-formation sequence. These results suggest that bulges in massive $z\sim2$ galaxies are actively building up, where the stars in the central concentration are relatively young. At $z<1$, the presence of older bulges within star-forming galaxies lowers global SFR/M$_\star$, decreasing the slope and contributing significantly to the scatter of the star-formation sequence.

@misc{whitaker2015galaxy, abstract = {It is well established that (1) star-forming galaxies follow a relation between their star formation rate (SFR) and stellar mass (M$_{\star}$), the "star-formation sequence", and (2) the SFRs of galaxies correlate with their structure, where star-forming galaxies are less concentrated than quiescent galaxies at fixed mass. Here, we consider whether the scatter and slope of the star-formation sequence is correlated with systematic variations in the Sersic indices, $n$, of galaxies across the SFR-M$_{\star}$ plane. We use a mass-complete sample of 23,848 galaxies at $0.5<z<2.5$ selected from the 3D-HST photometric catalogs. Galaxy light profiles parameterized by $n$ are based on Hubble Space Telescope CANDELS near-infrared imaging. We use a single SFR indicator empirically-calibrated from stacks of Spitzer/MIPS 24$\mu$m imaging, adding the unobscured and obscured star formation. We find that the scatter of the star-formation sequence is related in part to galaxy structure; the scatter due to variations in $n$ at fixed mass for star-forming galaxies ranges from 0.14$\pm$0.02 dex at $z\sim2$ to 0.30$\pm$0.04 dex at $z<1$. While the slope of the log(SFR)-log(M$_{\star}$) relation is of order unity for disk-like galaxies, galaxies with $n>2$ (implying more dominant bulges) have significantly lower SFR/M$_{\star}$ than the main ridgeline of the star-formation sequence. These results suggest that bulges in massive $z\sim2$ galaxies are actively building up, where the stars in the central concentration are relatively young. At $z<1$, the presence of older bulges within star-forming galaxies lowers global SFR/M$_{\star}$, decreasing the slope and contributing significantly to the scatter of the star-formation sequence.}, added-at = {2015-08-21T09:50:22.000+0200}, author = {Whitaker, Katherine E. and Franx, Marijn and Bezanson, Rachel and Brammer, Gabriel B. and van Dokkum, Pieter G. and Kriek, Mariska T. and Labbe, Ivo and Leja, Joel and Momcheva, Ivelina G. and Nelson, Erica J. and Rigby, Jane R. and Rix, Hans-Walter and Skelton, Rosalind E. and van der Wel, Arjen and Wuyts, Stijn}, biburl = {https://www.bibsonomy.org/bibtex/24b44bb867ae8c32d557c03d83ec3807e/miki}, description = {[1508.04771] Galaxy Structure as a Driver of the Star Formation Sequence Slope and Scatter}, interhash = {e422c5e4dc8e2991b508da64da45e468}, intrahash = {4b44bb867ae8c32d557c03d83ec3807e}, keywords = {formation galaxy star structure}, note = {cite arxiv:1508.04771Comment: Accepted for publication in the Astrophysical Journal Letters}, timestamp = {2015-08-21T09:50:22.000+0200}, title = {Galaxy Structure as a Driver of the Star Formation Sequence Slope and Scatter}, url = {http://arxiv.org/abs/1508.04771}, year = 2015 }