%0 Generic %1 Draganova2011 %A Draganova, N. %A Richter, P. %A Fechner, C. %D 2011 %K OVI component multi %T High-resolution observations of two OVI absorbers at z=2 towards PKS 1448-232 %U http://arxiv.org/abs/1110.4515 %X To explore the ionization conditions in highly-ionized absorbers at high redshift we have studied in detail two intervening OVI absorbers at z=2 towards the quasar PKS1448-232, based on high (R=75,000) and intermediate (R=45,000) resolution optical VLT/UVES spectra. We find that both absorption systems are composed of several narrow subcomponents with CIV/OVI Doppler-parameters b<10 km/s, typically. This implies that the gas temperatures are T<10^5 K and that the absorbers are photoionized by the UV background. The system at z=2.1098 represents a simple, isolated OVI absorber that has only two absorption components and that is relatively metal-rich (Z0.6 solar). Ioinization modeling implies that the system is photoionized with OVI, CIV, and HI coexisting in the same gas phase. The second system at z=2.1660 represents a complicated, multi-component absorption system with eight OVI components spanning almost 300 km/s in radial velocity. The photoionization modeling implies that the metallicity is non-uniform and relatively low (<= 0.1 solar) and that the OVI absorption must arise in a gas phase different from that traced by CIV, CIII, and HI. Our detailed study of the two OVI systems towards PKS1448-232 shows that multi-phase, multi-component high-ion absorbers like the one at z=2.1660 require a detailed ionization modeling of the various subcomponents to obtain reliable results on the physical conditions and metal-abundances in the gas.

@misc{Draganova2011, abstract = { To explore the ionization conditions in highly-ionized absorbers at high redshift we have studied in detail two intervening OVI absorbers at z=2 towards the quasar PKS1448-232, based on high (R=75,000) and intermediate (R=45,000) resolution optical VLT/UVES spectra. We find that both absorption systems are composed of several narrow subcomponents with CIV/OVI Doppler-parameters b<10 km/s, typically. This implies that the gas temperatures are T<10^5 K and that the absorbers are photoionized by the UV background. The system at z=2.1098 represents a simple, isolated OVI absorber that has only two absorption components and that is relatively metal-rich (Z\sim 0.6 solar). Ioinization modeling implies that the system is photoionized with OVI, CIV, and HI coexisting in the same gas phase. The second system at z=2.1660 represents a complicated, multi-component absorption system with eight OVI components spanning almost 300 km/s in radial velocity. The photoionization modeling implies that the metallicity is non-uniform and relatively low (<= 0.1 solar) and that the OVI absorption must arise in a gas phase different from that traced by CIV, CIII, and HI. Our detailed study of the two OVI systems towards PKS1448-232 shows that multi-phase, multi-component high-ion absorbers like the one at z=2.1660 require a detailed ionization modeling of the various subcomponents to obtain reliable results on the physical conditions and metal-abundances in the gas. }, added-at = {2011-10-21T18:32:10.000+0200}, author = {Draganova, N. and Richter, P. and Fechner, C.}, biburl = {https://www.bibsonomy.org/bibtex/2811899f3bcefbe03625b74677719c4c7/miki}, description = {[1110.4515] High-resolution observations of two OVI absorbers at z=2 towards PKS 1448-232}, interhash = {8ff81677641bd07b38c3fe67a2c57ab2}, intrahash = {811899f3bcefbe03625b74677719c4c7}, keywords = {OVI component multi}, note = {cite arxiv:1110.4515}, timestamp = {2011-10-21T18:32:10.000+0200}, title = {High-resolution observations of two OVI absorbers at z=2 towards PKS 1448-232}, url = {http://arxiv.org/abs/1110.4515}, year = 2011 }