Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation
| dc.creator | Padmanabhan, T. | |
| dc.creator | Subramanian, K. | |
| dc.date | 1993-10-07 | |
| dc.date.accessioned | 2026-07-07T02:18:55Z | |
| dc.date.available | 2026-07-07T02:18:55Z | |
| dc.description | 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 $Ω_b=Ω_{total}\simeq0.06$ 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, $Ω_b\simeq0.06,Ω_{cdm}\simeq0.94$, 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 $Ω_{dm}$, contributed by NBDM clustered at galactic scales, can only be about $Ω_{max}\simeq0.29$. Models with C+HDM cannot satisfy this constraint but $Λ$+ CDM models are still | |
| dc.description | 4 pages,IUCAA-23/93; sept,93; submitted for publication | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9310015 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9310015 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/9672 | |
| dc.subject | Astrophysics | |
| dc.title | Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation | |
| dc.type | text |