%0 Generic %1 martinnavarro2014stellar %A Martín-Navarro, I. %A Pérez-González, P. G. %A Trujillo, I. %A Esquej, P. %A Vazdekis, A. %A Sánchez, H. Domínguez %A Barro, G. %A Bruzual, G. %A Charlot, S. %A Cava, A. %A Ferreras, I. %A Espino, N. %A La Barbera, F. %D 2014 %K early high-z imf population stellar type %T The stellar initial mass function at z>1 %U http://arxiv.org/abs/1407.4455 %X We explore the stellar initial mass function (IMF) of a sample of 49 massive quiescent galaxies (MQGs) at 0.9<z<1.5. We base our analysis on intermediate resolution spectro-photometric data in the GOODS-N field taken in the near-infrared and optical with the HST/WFC3 G141 grism and the Survey for High-z Absorption Red and Dead Sources (SHARDS). To constrain the slope of the IMF, we have measured the TiO2 spectral feature, whose strength depends strongly on the content of low-mass stars, as well as on stellar age. Using ultraviolet to near-infrared individual and stacked spectral energy distributions, we have independently estimated the stellar ages of our galaxies. For the heaviest z~1 MQGs (M > 10^11.0 Msun) we find an average age of 1.7$\pm$0.3 Gyr and a bottom-heavy IMF (\Gamma=3.2$\pm$0.2). Lighter MQGs (10^10.5 < M < 10^11.0 Msun) at the same redshift are younger on average (1.0$\pm$0.2 Gyr) and present a shallower IMF slope (\Gamma=2.7$\pm$0.3). Our results are in good agreement with the findings about the IMF slope in early-type galaxies of similar mass in the present-day Universe. This suggests that the IMF, a key characteristic of the stellar populations in galaxies, is bottom-heavier for more massive galaxies and has remained unchanged in the last ~8 Gyr.

@misc{martinnavarro2014stellar, abstract = {We explore the stellar initial mass function (IMF) of a sample of 49 massive quiescent galaxies (MQGs) at 0.9<z<1.5. We base our analysis on intermediate resolution spectro-photometric data in the GOODS-N field taken in the near-infrared and optical with the HST/WFC3 G141 grism and the Survey for High-z Absorption Red and Dead Sources (SHARDS). To constrain the slope of the IMF, we have measured the TiO2 spectral feature, whose strength depends strongly on the content of low-mass stars, as well as on stellar age. Using ultraviolet to near-infrared individual and stacked spectral energy distributions, we have independently estimated the stellar ages of our galaxies. For the heaviest z~1 MQGs (M > 10^11.0 Msun) we find an average age of 1.7$\pm$0.3 Gyr and a bottom-heavy IMF ({\Gamma}=3.2$\pm$0.2). Lighter MQGs (10^10.5 < M < 10^11.0 Msun) at the same redshift are younger on average (1.0$\pm$0.2 Gyr) and present a shallower IMF slope ({\Gamma}=2.7$\pm$0.3). Our results are in good agreement with the findings about the IMF slope in early-type galaxies of similar mass in the present-day Universe. This suggests that the IMF, a key characteristic of the stellar populations in galaxies, is bottom-heavier for more massive galaxies and has remained unchanged in the last ~8 Gyr.}, added-at = {2014-07-18T10:22:15.000+0200}, author = {Martín-Navarro, I. and Pérez-González, P. G. and Trujillo, I. and Esquej, P. and Vazdekis, A. and Sánchez, H. Domínguez and Barro, G. and Bruzual, G. and Charlot, S. and Cava, A. and Ferreras, I. and Espino, N. and La Barbera, F.}, biburl = {https://www.bibsonomy.org/bibtex/2b4cbe7ab92ff15c8fe8a5e83b1e1ab8f/miki}, description = {[1407.4455] The stellar initial mass function at z&gt;1}, interhash = {9d2eea096ea12146a514d1eb66bbfd23}, intrahash = {b4cbe7ab92ff15c8fe8a5e83b1e1ab8f}, keywords = {early high-z imf population stellar type}, note = {cite arxiv:1407.4455Comment: 6 pages, 4 figures; submitted. Comments are welcome}, timestamp = {2014-07-18T10:22:15.000+0200}, title = {The stellar initial mass function at z>1}, url = {http://arxiv.org/abs/1407.4455}, year = 2014 }