Spherical collapse and virialization in f ( T ) gravities
Abstract
Using the classical tophat profile, we study the nonlinear growth of spherically symmetric density perturbation and structure formation in f ( T ) gravities. In particular, three concrete models, which have been tested against the observation of largescale evolution and linear perturbation of the universe in the cosmological scenario, are investigated in this framework, covering both minimal and nonminimal coupling cases of f ( T ) gravities. Moreover, we consider the virialization of the overdense region in the models after they detach from the background expanding universe and turn around to collapse. We find that there are constraints in the magnitude and occurring epoch of the initial perturbation. The existence of these constraints indicates that a perturbation that is too weak or occurs too late will not be able to stop the expanding of the overdense region. The illustration of the evolution of the perturbation shows that in f ( T ) gravities, the initial perturbation within the constraints can eventually lead to clustering and form structure. The evolution also shows that nonminimal coupling models collapse slower than the minimal coupling one.
 Authors:
 Shanghai United Center for Astrophysics (SUCA), Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)
 Publication Date:
 OSTI Identifier:
 22679964
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 03; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COUPLING; COVERINGS; DENSITY; DISTURBANCES; GRAVITATION; NONLINEAR PROBLEMS; PERTURBATION THEORY; QUANTUM GRAVITY; SIMULATION; SPHERICAL CONFIGURATION; SYMMETRY; UNIVERSE
Citation Formats
Lin, RuiHui, Zhai, XiangHua, and Li, XinZhou, Email: 1000379711@smail.shnu.edu.cn, Email: zhaixh@shnu.edu.cn, Email: kychz@shnu.edu.cn. Spherical collapse and virialization in f ( T ) gravities. United States: N. p., 2017.
Web. doi:10.1088/14757516/2017/03/040.
Lin, RuiHui, Zhai, XiangHua, & Li, XinZhou, Email: 1000379711@smail.shnu.edu.cn, Email: zhaixh@shnu.edu.cn, Email: kychz@shnu.edu.cn. Spherical collapse and virialization in f ( T ) gravities. United States. doi:10.1088/14757516/2017/03/040.
Lin, RuiHui, Zhai, XiangHua, and Li, XinZhou, Email: 1000379711@smail.shnu.edu.cn, Email: zhaixh@shnu.edu.cn, Email: kychz@shnu.edu.cn. Wed .
"Spherical collapse and virialization in f ( T ) gravities". United States.
doi:10.1088/14757516/2017/03/040.
@article{osti_22679964,
title = {Spherical collapse and virialization in f ( T ) gravities},
author = {Lin, RuiHui and Zhai, XiangHua and Li, XinZhou, Email: 1000379711@smail.shnu.edu.cn, Email: zhaixh@shnu.edu.cn, Email: kychz@shnu.edu.cn},
abstractNote = {Using the classical tophat profile, we study the nonlinear growth of spherically symmetric density perturbation and structure formation in f ( T ) gravities. In particular, three concrete models, which have been tested against the observation of largescale evolution and linear perturbation of the universe in the cosmological scenario, are investigated in this framework, covering both minimal and nonminimal coupling cases of f ( T ) gravities. Moreover, we consider the virialization of the overdense region in the models after they detach from the background expanding universe and turn around to collapse. We find that there are constraints in the magnitude and occurring epoch of the initial perturbation. The existence of these constraints indicates that a perturbation that is too weak or occurs too late will not be able to stop the expanding of the overdense region. The illustration of the evolution of the perturbation shows that in f ( T ) gravities, the initial perturbation within the constraints can eventually lead to clustering and form structure. The evolution also shows that nonminimal coupling models collapse slower than the minimal coupling one.},
doi = {10.1088/14757516/2017/03/040},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 03,
volume = 2017,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}

We calculate the nonlinear virialization density, Δ{sub c}, of halos under spherical collapse from peaks with an arbitrary initial and final density profile. This is in contrast to the standard calculation of Δ{sub c} which assumes tophat profiles. Given our formalism, the nonlinear halo density can be calculated once the shape of the initial peak's density profile and the shape of the virialized halo's profile are provided. We solve for Δ{sub c} for halos in an Einstein deSitter and a ΛCDM universe. As examples, we consider powerlaw initial profiles as well as spherically averaged peak profiles calculated from the statisticsmore »

GT strength distribution in fp shell nuclei and {nu}{sub {ital e}} from stellar collapse
The GamowTeller strength distribution in fp shell nuclei is important in determining {ital e}{sup {minus}}capture and {beta}decay rates on neutron rich nuclei in presupernova and collapsing cores of massive stars. We use the recently available data for pn and np reactions on some of these nuclei to generate a generalized relation for the centroid (in energy) of the GT distribution in terms of nuclear mass number and neutron excess. We then calculate the energy spectrum of the electroncapture neutrinos which stream freely out of the collapsing star {ital without} {ital further} {ital interactions} (i.e., the pretrapping neutrinos). The number andmore »