Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation

Details Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation

1993-10-07

arxiv.org/abs/astro-ph/9310015v1

Astronomy and Astrophysics

Astrophysics

4 pages,IUCAA-23/93; sept,93; submitted for publication

Scientific paper

The recent detection of microlensing of stars of LMC by compact objects in the halo of our galaxy suggests that our galaxy is surrounded by a non-luminous halo made of compact objects with mass of about $(0.03-0.5) \msun$. The rate of detection could be consistent with the assumption that these halo objects are distributed with a softened isothermal profile with a core radius of $(2-8)$Kpc and asymptotic circular velocity of $220\kms$. Taken in isolation, this observation is consistent with a universe having only baryonic dark matter (BDM, hereafter) contributing $\Omega_b=\Omega_{total}\simeq0.06$ which will, however, violently contradict several other large scale observations, notably the COBE-DMR results. Alternatively one can assume that galaxies like ours are surrounded by both BDM and non-baryonic dark matter (NBDM, hereafter). A model with a single component for NBDM with, say, $\Omega_b\simeq0.06,\Omega_{cdm}\simeq0.94$, is also ruled out if we demand that: (i) at least thirty percent of the dark matter density within $100$ kpc is baryonic and (ii) galactic structures should have collapsed by redshift of $z=1$. Further if half or more of the dark matter within $100 kpc$ is baryonic then the maximum value of $\Omega_{dm}$, contributed by NBDM clustered at galactic scales, can only be about $\Omega_{max}\simeq0.29$. Models with C+HDM cannot satisfy this constraint but $\Lambda$+ CDM models are still

Affiliated with

Also associated with

No associations

Rating

Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation 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 Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-122548