%0 Generic %1 berg2016selection %A Berg, T. A. M. %A Ellison, S. L. %A Prochaska, J. X. %A Sanchez-Ramirez, R. %A Lopez, S. %A D'Odorico, V. %A Becker, G. %A Christensen, L. %A Cupani, G. %A Denney, K. %A Worseck, G. %D 2016 %K DLA MgII high-z selection %T On the selection of damped Lyman alpha systems using MgII absorption at 2<z<4 %U http://arxiv.org/abs/1609.09081 %X The XQ-100 survey provides optical and near infrared coverage of 36 blindly selected, intervening damped Lyman alpha systems (DLAs) at 2 < z < 4, simultaneously covering the MgII doublet at 2796A, 2803A, and the Ly-alpha transition. Using the XQ-100 DLA sample, we investigate the completeness of selecting DLA absorbers based on their MgII rest-frame equivalent width (W2796) at these redshifts. Of the 29 DLAs with clean MgII profiles, we find that six (20% of DLAs) have W2796 < 0.6A. The DLA incidence rate of W2796 < 0.6A absorbers is a factor of ~5 higher than what is seen in z~1 samples, indicating a potential evolution in the MgII properties of DLAs with redshift. All of the W2796 < 0.6A DLAs have low metallicities (-2.5 < M/H < -1.7), small velocity widths (v90 < 50 km/s), and tend to have relatively low N(HI). We demonstrate that the exclusion of these low W2796 DLAs results in a higher mean N(HI) which in turn leads to a ~7% increase in the cosmological gas density of HI of DLAs at 2 < z < 4; and that this exclusion has a minimal effect on the HI-weighted mean metallicity.

@misc{berg2016selection, abstract = {The XQ-100 survey provides optical and near infrared coverage of 36 blindly selected, intervening damped Lyman alpha systems (DLAs) at 2 < z < 4, simultaneously covering the MgII doublet at 2796A, 2803A, and the Ly-alpha transition. Using the XQ-100 DLA sample, we investigate the completeness of selecting DLA absorbers based on their MgII rest-frame equivalent width (W2796) at these redshifts. Of the 29 DLAs with clean MgII profiles, we find that six (20% of DLAs) have W2796 < 0.6A. The DLA incidence rate of W2796 < 0.6A absorbers is a factor of ~5 higher than what is seen in z~1 samples, indicating a potential evolution in the MgII properties of DLAs with redshift. All of the W2796 < 0.6A DLAs have low metallicities (-2.5 < [M/H] < -1.7), small velocity widths (v90 < 50 km/s), and tend to have relatively low N(HI). We demonstrate that the exclusion of these low W2796 DLAs results in a higher mean N(HI) which in turn leads to a ~7% increase in the cosmological gas density of HI of DLAs at 2 < z < 4; and that this exclusion has a minimal effect on the HI-weighted mean metallicity.}, added-at = {2016-09-30T10:03:17.000+0200}, author = {Berg, T. A. M. and Ellison, S. L. and Prochaska, J. X. and Sanchez-Ramirez, R. and Lopez, S. and D'Odorico, V. and Becker, G. and Christensen, L. and Cupani, G. and Denney, K. and Worseck, G.}, biburl = {https://www.bibsonomy.org/bibtex/2f9ededd7a7d2d3a6be6fbd7b2cb2103c/miki}, description = {[1609.09081] On the selection of damped Lyman alpha systems using MgII absorption at 2&lt;z&lt;4}, interhash = {7a2eeb574c589e57c81c3729cbfba603}, intrahash = {f9ededd7a7d2d3a6be6fbd7b2cb2103c}, keywords = {DLA MgII high-z selection}, note = {cite arxiv:1609.09081Comment: Accepted into MNRAS Letters. 6 pages, 2 figures}, timestamp = {2016-09-30T10:03:17.000+0200}, title = {On the selection of damped Lyman alpha systems using MgII absorption at 2<z<4}, url = {http://arxiv.org/abs/1609.09081}, year = 2016 }