%0 Generic %1 lehner2014galactic %A Lehner, Nicolas %A O'Meara, John M. %A Fox, Andrew J. %A Howk, J. Christopher %A Prochaska, J. Xavier %A Burns, Vincent %A Armstrong, Ashley A. %D 2014 %K circumgalactic dla lls medium ovi %T Galactic and Circumgalactic OVI and its Impact on the Cosmological Metal and Baryon Budgets at 2<z<3.5 %U http://arxiv.org/abs/1401.1811 %X We present the first results from our NASA KODIAQ survey, which aims to characterize the properties of the highly ionized gas associated with absorbers that are optically thick at the Lyman limit at 2<z<4, an epoch corresponding to the peak level of the star formation in the universe. These absorbers are known to probe galaxies and their circumgalactic medium (CGM). In this first paper, we assemble a sample where the main selection criteria are that the absorbers have log N(HI)> 17 and both transitions of the OVI doublet have little contamination. We found 20 absorbers that satisfy these rules, the sample being divided in 7 Lyman limit systems (LLSs, here with 17.7<log N(HI)<19), 8 super-LLSs (SLLSs, here with 19.6<log N(HI)<20.3) and 5 damped Lya (DLAs, log N(HI)> 20.3). The OVI detection rate in this sample is 100% for the DLAs, 71% for the LLSs, and 63% for the SLLSs. When OVI is detected, we find log<N(OVI)>=14.9+/-0.3, which is much larger and with a smaller dispersion than in blind OVI surveys. Strong OVI absorption is therefore nearly ubiquitous in the CGM of z~2-3 galaxies. The total velocity widths of the OVI profiles are also large (200< Delta v(OVI)<400 km/s). These properties strongly suggest these OVI absorbers probe gas associated with outflows of star-forming galaxies at 2<z<3.5. The LLSs and SLLSs with no OVI absorption have properties consistent with those seen in cosmological simulations tracing cold streams feeding galaxies. When the highly ionized gas is taken into account, we determine that the optically thick absorbers contain as much as 5-15% of the cosmic baryon budget at z~2-3. We conservatively show that at least 10% of the metals ever produced at z~2-3 are in form of highly ionized metals ejected in the CGM of galaxies; combined with estimates of other metal reservoirs, this is essentially enough to close the cosmic metal budget at z~2-3.

@misc{lehner2014galactic, abstract = {We present the first results from our NASA KODIAQ survey, which aims to characterize the properties of the highly ionized gas associated with absorbers that are optically thick at the Lyman limit at 2<z<4, an epoch corresponding to the peak level of the star formation in the universe. These absorbers are known to probe galaxies and their circumgalactic medium (CGM). In this first paper, we assemble a sample where the main selection criteria are that the absorbers have log N(HI)> 17 and both transitions of the OVI doublet have little contamination. We found 20 absorbers that satisfy these rules, the sample being divided in 7 Lyman limit systems (LLSs, here with 17.7<log N(HI)<19), 8 super-LLSs (SLLSs, here with 19.6<log N(HI)<20.3) and 5 damped Lya (DLAs, log N(HI)> 20.3). The OVI detection rate in this sample is 100% for the DLAs, 71% for the LLSs, and 63% for the SLLSs. When OVI is detected, we find log<N(OVI)>=14.9+/-0.3, which is much larger and with a smaller dispersion than in blind OVI surveys. Strong OVI absorption is therefore nearly ubiquitous in the CGM of z~2-3 galaxies. The total velocity widths of the OVI profiles are also large (200< Delta v(OVI)<400 km/s). These properties strongly suggest these OVI absorbers probe gas associated with outflows of star-forming galaxies at 2<z<3.5. The LLSs and SLLSs with no OVI absorption have properties consistent with those seen in cosmological simulations tracing cold streams feeding galaxies. When the highly ionized gas is taken into account, we determine that the optically thick absorbers contain as much as 5-15% of the cosmic baryon budget at z~2-3. We conservatively show that at least 10% of the metals ever produced at z~2-3 are in form of highly ionized metals ejected in the CGM of galaxies; combined with estimates of other metal reservoirs, this is essentially enough to close the cosmic metal budget at z~2-3.}, added-at = {2014-01-10T15:10:39.000+0100}, author = {Lehner, Nicolas and O'Meara, John M. and Fox, Andrew J. and Howk, J. Christopher and Prochaska, J. Xavier and Burns, Vincent and Armstrong, Ashley A.}, biburl = {https://www.bibsonomy.org/bibtex/2b0c510e77fba7414fc6cd873274b1c35/miki}, description = {[1401.1811] Galactic and Circumgalactic OVI and its Impact on the Cosmological Metal and Baryon Budgets at 2&lt;z&lt;3.5}, interhash = {78fdd02afeeab754f1bd1ead439b8509}, intrahash = {b0c510e77fba7414fc6cd873274b1c35}, keywords = {circumgalactic dla lls medium ovi}, note = {cite arxiv:1401.1811Comment: Submitted to the ApJ}, timestamp = {2014-01-10T15:10:39.000+0100}, title = {Galactic and Circumgalactic OVI and its Impact on the Cosmological Metal and Baryon Budgets at 2<z<3.5}, url = {http://arxiv.org/abs/1401.1811}, year = 2014 }