Testing HOD modelYu Liang

Tsinghua University &Instituto de Física Teórica (IFT), Universidad Autónoma de Madrid (UAM)

Background

Five parameter HOD model

Motivation-testing HOD model

Varying the five parameters to fit the correlation function.

After the correlation is fitted well, we check how it will be in power spectrum.

We guess HOD model with five parameters can fit any correlation but it won’t be so well even though correlation function is well fitted.

Catalogs

CatalgoAccSm.a.0.65.DAT (get from Anatoly , some one named peter created sub-sub-halo, original from BDMV)

BDMV (whole catalog and with 6.3E13 mass cut to select distinct halo)

BDMW (whole catalog and with 6.3E13 mass cut to select distinct halo)

FOF with particles (whole catalog and with 6.3E13 mass cut to select distinct halo)

Get data by Query the MultiDark Database (few days) haloid=$((62000000000+$i))sql=“select top 5 fofId, p.particleId, snapnum, x, y, z, vx, vy, vz, phkey from MDR1..FOFParticles62 as fp inner join MDR1..particles62 as p on fp.particleId = p.particleId where fp.fofId = $haloid order by newid()"

Get data by Query the MultiDark Database (few hours)with tmp as ( select row_number() over ( partition by fofId order by newid() ) as 'rownum', fofId, particleId from MDR1..FOFparticles62 where fofId between 62000400000 $plus $i $times 1e3 and 62000400999 $plus $i $times 1e3)select fp.fofId , p.* from tmp as fp , MDR1..particles62 as pWhere fp.particleId = p.particleId and fp.rownum <= 5Order by fofId, particleId

Correlation function

Check what’s going on with the subhalo

Compute the correlation function of subhalos "only“

Compute the distance between each subhalo and its parent distinct halo, and then make a distribution

Check what’s going on with the subhalo The typical size of a halo is smaller than 1 Mpc/h and it is why we have

very large power at first bin.

The subhalo picked in my way would boost the power of the correlation function. In addition, we found the subhalos are living very close to distinct halos (i.e. < 1Mpc/h) and that is why we have large power at first two bins (r < 2Mpc/h)

Use HOD to assign galaxy

HOD model Difference between papers

a, No central galaxy, no satellite galaxy.

b, Satellite galaxies can exist without central galaxy.

c, Nsat=[(M-M0)/M1]^alpha (astro-ph/0408564 ZhengZheng et al)

d, Nsat=Ncen*[(M-M0)/M1]^alpha (astro-ph/0703457 ZhengZheng et al)

e, Nsat=(M/M1)^alpha * exp(-Mcut/M1) (arXiv 1202:6057V4)

Varying five parameters

The mean occupancy of all haloes in our MultiDark sample

Fig 8. Nuza et al 2013

Thank you!