Publication Date:
2014-03-01
Description:
We present the cross-correlation function of Mg ii absorbers with respect to a volume-limited sample of luminous red galaxies (LRGs) at z = 0.45–0.60 using the largest Mg ii absorber sample and a new LRG sample from Sloan Digital Sky Survey Data Release 7. We present the clustering signal of absorbers on projected scales r p = 0.3-35 h –1 Mpc in four $W_{\rm r}^{\lambda 2796}$ bins spanning $W_{\rm r}^{\lambda 2796}=0.4{\rm -}5.6$ Å. We found that on average Mg ii absorbers reside in haloes 〈log M h 〉 12.1, similar to the halo mass of an L * galaxy. We report that the weakest absorbers in our sample with $W_{\rm r}^{\lambda 2796}=0.4{\rm -}1.1$ Å reside in relatively massive haloes with $\langle \log M_{\rm h} \rangle \approx 12.5^{+0.6}_{-1.3}$ , while stronger absorbers reside in haloes of similar or lower masses 〈log M h 〉 11.6 + 0.9 . We compared our bias data points, b , and the frequency distribution function of absorbers, $f_{W_{\rm r}}$ , with a simple model incorporating an isothermal density profile to mimic the distribution of absorbing gas in haloes. We also compared the bias data points with Tinker & Chen who developed halo occupation distribution models of Mg ii absorbers that are constrained by b and $f_{W_{\rm r}}$ . The simple isothermal model can be ruled at a 2.8 level mostly because of its inability to reproduce $f_{W_{\rm r}}$ . However, b values are consistent with both models, including Tinker & Chen. In addition, we show that the mean b of absorbers does not decrease beyond $W_{\rm r}^{\lambda 2796} \approx 1.6$ Å. The flat or potential upturn of b for $W_{\rm r}^{\lambda 2796}\gtrsim 1.6$ Å absorbers suggests the presence of additional cool gas in massive haloes.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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