The halo mass function conditioned on density from the Millennium Simulation: insights into missing baryons and galaxy mass functions

Details The halo mass function conditioned on density from the Millennium Simulation: insights into missing baryons and galaxy mass functions The halo mass function conditioned on density from the Millennium Simulation: insights into missing baryons and galaxy mass functions

2010-02-03

arxiv.org/abs/1002.0844v2

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

aligned with version published in ApJ

Scientific paper

The baryon content of high-density regions in the universe is relevant to two critical unanswered questions: the workings of nurture effects on galaxies and the whereabouts of the missing baryons. In this paper, we analyze the distribution of dark matter and semianalytical galaxies in the Millennium Simulation to investigate these problems. Applying the same density field reconstruction schemes as used for the overall matter distribution to the matter locked in halos we study the mass contribution of halos to the total mass budget at various background field densities, i.e., the conditional halo mass function. In this context, we present a simple fitting formula for the cumulative mass function accurate to ~ 5% for halo masses between 10^{10} and 10^{15}Msol/h. We find that in dense environments the halo mass function becomes top heavy and present corresponding fitting formulae for different redshifts. We demonstrate that the major fraction of matter in high-density fields is associated with galaxy groups. Since current X-ray surveys are able to nearly recover the universal baryon fraction within groups, our results indicate that the major part of the so-far undetected warm-hot intergalactic medium resides in low-density regions at low temperatures. Similarly, we show that the differences in galaxy mass functions with environment seen in observed and simulated data stem predominantly from differences in the mass distribution of halos. In particular, the hump in the galaxy mass function is associated with the central group galaxies, and the bimodality observed in the galaxy mass function is therefore interpreted as that of central galaxies versus satellites.

Affiliated with

Also associated with

No associations

Rating

The halo mass function conditioned on density from the Millennium Simulation: insights into missing baryons and galaxy mass functions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The halo mass function conditioned on density from the Millennium Simulation: insights into missing baryons and galaxy mass functions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The halo mass function conditioned on density from the Millennium Simulation: insights into missing baryons and galaxy mass functions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-154118