%0 Generic %1 du2019searching %A Du, Xinnan %A Shapley, Alice E. %A Tang, Mengtao %A Stark, Daniel P. %A Martin, Crystal L. %A Mobasher, Bahram %A Topping, Michael W. %A Chevallard, Jacopo %D 2019 %K library %T Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation %U http://arxiv.org/abs/1910.11877 %X Strong OIII$łambdałambda$4959,5007+H$\beta$ emission appears to be typical in star-forming galaxies at z > 6.5. As likely contributors to cosmic reionization, these galaxies and the physical conditions within them are of great interest. At z > 6.5, where Ly$\alpha$ is greatly attenuated by the intergalactic medium, rest-UV metal emission lines provide an alternative measure of redshift and also constraints on the physical properties of star-forming regions and massive stars. We present the first statistical sample of rest-UV line measurements in z $\sim$ 2 galaxies selected as analogs of those in the reionization era based on OIII$łambdałambda$4959,5007 EW or rest-frame U-B color. Our sample is drawn from the 3D-HST Survey and spans the redshift range 1.36 $łeqslant$ z $łeqslant$ 2.49. We find that the median Ly$\alpha$ and CIII$łambdałambda$1907,1909 EWs of our sample are significantly greater than those of z $\sim$ 2 UV-continuum-selected star-forming galaxies. Measurements from both individual and composite spectra indicate a monotonic, positive correlation between CIII and OIII, while a lack of trend is observed between Ly$\alpha$ and OIII at OIII EW < 1000$x212B$. At higher OIII EW, extreme Ly$\alpha$ emission starts to emerge. Using stacked spectra, we find that Ly$\alpha$ and CIII are significantly enhanced in galaxies with lower metallicity. Two objects in our sample appear comparable to z > 6.5 galaxies with exceptionally strong rest-UV metal line emission. These objects have significant CIV$łambdałambda$1548,1550, HeII$łambda$1640, and OIII$łambdałambda$1661,1665 emission in addition to intense Ly$\alpha$ or CIII. Detailed characterization of these lower-redshift analogs provides unique insights into the physical conditions in z > 6.5 star-forming regions, motivating future observations of reionization-era analogs at lower redshifts.

@misc{du2019searching, abstract = {Strong [OIII]$\lambda\lambda$4959,5007+H$\beta$ emission appears to be typical in star-forming galaxies at z > 6.5. As likely contributors to cosmic reionization, these galaxies and the physical conditions within them are of great interest. At z > 6.5, where Ly$\alpha$ is greatly attenuated by the intergalactic medium, rest-UV metal emission lines provide an alternative measure of redshift and also constraints on the physical properties of star-forming regions and massive stars. We present the first statistical sample of rest-UV line measurements in z $\sim$ 2 galaxies selected as analogs of those in the reionization era based on [OIII]$\lambda\lambda$4959,5007 EW or rest-frame U-B color. Our sample is drawn from the 3D-HST Survey and spans the redshift range 1.36 $\leqslant$ z $\leqslant$ 2.49. We find that the median Ly$\alpha$ and CIII]$\lambda\lambda$1907,1909 EWs of our sample are significantly greater than those of z $\sim$ 2 UV-continuum-selected star-forming galaxies. Measurements from both individual and composite spectra indicate a monotonic, positive correlation between CIII] and [OIII], while a lack of trend is observed between Ly$\alpha$ and [OIII] at [OIII] EW < 1000$\unicode{x212B}$. At higher [OIII] EW, extreme Ly$\alpha$ emission starts to emerge. Using stacked spectra, we find that Ly$\alpha$ and CIII] are significantly enhanced in galaxies with lower metallicity. Two objects in our sample appear comparable to z > 6.5 galaxies with exceptionally strong rest-UV metal line emission. These objects have significant CIV$\lambda\lambda$1548,1550, HeII$\lambda$1640, and OIII]$\lambda\lambda$1661,1665 emission in addition to intense Ly$\alpha$ or CIII]. Detailed characterization of these lower-redshift analogs provides unique insights into the physical conditions in z > 6.5 star-forming regions, motivating future observations of reionization-era analogs at lower redshifts.}, added-at = {2019-10-29T07:38:25.000+0100}, author = {Du, Xinnan and Shapley, Alice E. and Tang, Mengtao and Stark, Daniel P. and Martin, Crystal L. and Mobasher, Bahram and Topping, Michael W. and Chevallard, Jacopo}, biburl = {https://www.bibsonomy.org/bibtex/27e2ef8741709165ce9cea87c2f28132e/gpkulkarni}, description = {Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation}, interhash = {40c6ee8029ca8acfcae768d233c0c50d}, intrahash = {7e2ef8741709165ce9cea87c2f28132e}, keywords = {library}, note = {cite arxiv:1910.11877Comment: 21 pages, 9 figures, submitted to ApJ}, timestamp = {2019-10-29T07:38:25.000+0100}, title = {Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation}, url = {http://arxiv.org/abs/1910.11877}, year = 2019 }