%0 Generic %1 khostovan2016nature %A Khostovan, Ali Ahmad %A Sobral, David %A Mobasher, Bahram %A Smail, Ian %A Darvish, Behnam %A Nayyeri, Hooshang %A Hemmati, Shoubaneh %A Stott, John P. %D 2016 %K emission evolution galaxies line %T The Nature of H$\beta+$Oiii and Oii emitters to $z \sim 5$ with HiZELS: stellar mass functions and the evolution of EWs %U http://arxiv.org/abs/1604.02456 %X We investigate the properties of $\sim7000$ narrow-band selected galaxies with strong H$\beta+$OIII and OII nebular emission lines from the High-$z$ Emission Line Survey (HiZELS) between $z 0.8 - 5.0$. Our sample covers a wide range in stellar mass ($M\sim10^7.5 - 12.0$ M$_ødot$), rest-frame equivalent widths (EW$_rest10 - 10^5$ \AA), and line luminosities ($L\sim10^40.5 - 43.2$ erg s$^-1$). We measure the H$\beta+$OIII and OII-selected stellar mass functions out to $z 3.5$ and find that both $M_\star$ and $\phi_\star$ increases with cosmic time, which may be due to the OIII selection including an increasing fraction of AGN at lower redshifts. The OII-selected stellar mass functions show a constant $M_\star\sim10^11.6$ M$_ødot$ and a strong, increasing evolution with cosmic time in $\phi_\star$ in line with H$\alpha$ studies. We also investigate the EW$_rest$ evolution as a function of redshift with a fixed mass range (10$^9.5 - 10.0$ M$_ødot$) and find an increasing trend best represented by $(1+z)^3.81\pm0.14$ and $(1+z)^2.72\pm0.19$ up to $z2$ and $3$ for H$\beta$+OIII and OII emitters, respectively. This is the first time that the EW evolution has been directly measured for H$\beta+$OIII and OII emitters up to these redshifts. There is evidence for a slower evolution for $z > 2$ in the H$\beta+$OIII EW and a decreasing trend for $z > 3$ in the OII EW evolution, which would imply low OII EW at the highest redshifts and higher OIII/OII line ratios. This suggests that the ionization parameter at higher redshift may be significantly higher than the local Universe. Our results set the stage for future near-IR space-based spectroscopic surveys to test our extrapolated predictions and also produce $z > 5$ measurements to constrain the high-$z$ end of the EW$_rest$ and OIII/OII evolution.

@misc{khostovan2016nature, abstract = {We investigate the properties of $\sim7000$ narrow-band selected galaxies with strong H$\beta+$[OIII] and [OII] nebular emission lines from the High-$z$ Emission Line Survey (HiZELS) between $z \sim 0.8 - 5.0$. Our sample covers a wide range in stellar mass ($M\sim10^{7.5 - 12.0}$ M$_\odot$), rest-frame equivalent widths (EW$_\mathrm{rest}\sim 10 - 10^5$ \AA), and line luminosities ($L\sim10^{40.5 - 43.2}$ erg s$^{-1}$). We measure the H$\beta+$[OIII] and [OII]-selected stellar mass functions out to $z \sim 3.5$ and find that both $M_\star$ and $\phi_\star$ increases with cosmic time, which may be due to the [OIII] selection including an increasing fraction of AGN at lower redshifts. The [OII]-selected stellar mass functions show a constant $M_\star\sim10^{11.6}$ M$_\odot$ and a strong, increasing evolution with cosmic time in $\phi_\star$ in line with H$\alpha$ studies. We also investigate the EW$_\mathrm{rest}$ evolution as a function of redshift with a fixed mass range (10$^{9.5 - 10.0}$ M$_\odot$) and find an increasing trend best represented by $(1+z)^{3.81\pm0.14}$ and $(1+z)^{2.72\pm0.19}$ up to $z\sim 2$ and $\sim 3$ for H$\beta$+[OIII] and [OII] emitters, respectively. This is the first time that the EW evolution has been directly measured for H$\beta+$[OIII] and [OII] emitters up to these redshifts. There is evidence for a slower evolution for $z > 2$ in the H$\beta+$[OIII] EW and a decreasing trend for $z > 3$ in the [OII] EW evolution, which would imply low [OII] EW at the highest redshifts and higher [OIII]/[OII] line ratios. This suggests that the ionization parameter at higher redshift may be significantly higher than the local Universe. Our results set the stage for future near-IR space-based spectroscopic surveys to test our extrapolated predictions and also produce $z > 5$ measurements to constrain the high-$z$ end of the EW$_\mathrm{rest}$ and [OIII]/[OII] evolution.}, added-at = {2016-04-12T12:13:18.000+0200}, author = {Khostovan, Ali Ahmad and Sobral, David and Mobasher, Bahram and Smail, Ian and Darvish, Behnam and Nayyeri, Hooshang and Hemmati, Shoubaneh and Stott, John P.}, biburl = {https://www.bibsonomy.org/bibtex/2c4aea7dda6f6ebc6e02f91623ca14fba/miki}, description = {[1604.02456] The Nature of H$\beta+$[O{\sc iii}] and [O{\sc ii}] emitters to $z \sim 5$ with HiZELS: stellar mass functions and the evolution of EWs}, interhash = {515810c686b61caf0d7e2558644f35bb}, intrahash = {c4aea7dda6f6ebc6e02f91623ca14fba}, keywords = {emission evolution galaxies line}, note = {cite arxiv:1604.02456Comment: 20 pages, 10 figures, 6 tables, submitted to MNRAS}, timestamp = {2016-04-12T12:13:18.000+0200}, title = {The Nature of H$\beta+$[O{\sc iii}] and [O{\sc ii}] emitters to $z \sim 5$ with HiZELS: stellar mass functions and the evolution of EWs}, url = {http://arxiv.org/abs/1604.02456}, year = 2016 }