A Halo Occupation Interpretation Of Quasars At $zsim1.5$ Using Very Small Scale Clustering Information


Abstract in English

We combine the most precise small scale ($< 100, rm h^{-1}kpc$) quasar clustering constraintsto date with recent measurements at large scales ($> 1, rm h^{-1}Mpc$) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) to better constrain the satellite fraction of quasars at $zsim 1.5$ in the halo occupation formalism. We build our Halo Occupation Distribution (HOD) framework based on commonly used analytic forms for the one and two-halo terms with two free parameters: the minimum halo mass that hosts a central quasar and the fraction of satellite quasars that are within one halo. Inspired by recent studies that propose a steeper density profile for the dark matter haloes that host quasars, we explore HOD models at kiloparsec scales and best-fit parameters for models with $10times$ higher concentration parameter. We find that an HOD model with a satellite fraction of $f_{rm sat} = 0.071_{-0.004}^{+0.009}$ and minimum mass of $rm M_{m} = 2.31_{-0.38}^{+0.41} times 10^{12}, , rm h^{-1} M_{odot}$ for the host dark matter haloes best describes quasar clustering (on all scales) at $z sim 1.5$. Our results are marginally inconsistent with earlier work that studied brighter quasars, hinting at a luminosity-dependence to the one-halo term.

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