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Primordial magnetic fields (PMFs) play a pivotal role in influencing small-scale fluctuations within the primordial density field, thereby enhancing the matter power spectrum within the context of the $\Lambda$CDM model at small scales.…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-02 Qile Zhang , Shang Li , Xiu-Hui Tan , Jun-Qing Xia

Sun like stars are born from the collapse of fragment of molecular clouds. During the first embedded phase (the so called class 0/1), the protostar is surrounded by a collapsing envelope, whose physical and chemical structure would set up…

Astrophysics · Physics 2009-11-07 S. Maret , C. Ceccarelli , E. Caux , A. G. G. M. Tielens , A. Castets

We reconstruct the shape of the primordial power spectrum from the latest cosmic microwave background data, including the new results from the Wilkinson Microwave Anisotropy Probe (WMAP), and large scale structure data from the two degree…

Astrophysics · Physics 2009-11-07 S. L. Bridle , A. M. Lewis , J. Weller , G. Efstathiou

We examine the effects of cosmic strings on structure formation and on the ionization history of the universe. While Gaussian perturbations from inflation are known to provide the dominant contribution to the large scale structure of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Benjamin Shlaer , Alexander Vilenkin , Abraham Loeb

Many questions in physical cosmology regarding the thermal history of the intergalactic medium, chemical enrichment, reionization, etc. are thought to be intimately related to the nature and evolution of pregalactic structure. In particular…

Astrophysics · Physics 2007-05-23 Tom Abel , Greg L. Bryan , Michael L. Norman

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

We present high-resolution simulations of the first star-forming clouds in 15 minihalos with masses ranging from $\sim 10^5$ to $10^7\ \text{M}_{\odot}$ at redshifts $z \sim 17-20$, using the GIZMO code. Our simulations incorporate detailed…

Astrophysics of Galaxies · Physics 2026-05-28 Meng-Yuan Ho , Ke-Jung Chen , Pei-Cheng Tung

Primordial black holes may have formed in the radiative era of the early Universe from the collapse of large enough amplitude perturbations of the metric. These correspond to non linear energy density perturbations characterized by an…

General Relativity and Quantum Cosmology · Physics 2020-01-06 Ilia Musco

The effects that large scale fluctuations had on small scale isothermal modes at the epoch of recombination are analysed. We find that: (a) Albeit the fact that primordial fluctuations were at this epoch still well in the linear regime, a…

Astrophysics · Physics 2009-10-30 Nir J. Shaviv

It has been hypothesized that the cosmic microwave background (CMB) provides a temperature floor for collapsing protostars that can regulate the process of star formation and result in a top-heavy initial mass function at high metallicity…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Jeremy Bailin , Greg Stinson , Hugh Couchman , William E. Harris , James Wadsley , Sijing Shen

The initial power spectrum of density perturbations, generated during the inflationary epoch, is now constrained by observations on scales $\lambda>5$~Mpc and has a power-law form. The peculiarities of the inflationary process can lead to…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 S. V. Pilipenko , S. A. Drozdov , M. V. Tkachev , A. G. Doroshkevich

We report results from numerical simulations of star formation in the early universe that focus on gas at very high densities and very low metallicities. We argue that the gas in the central regions of protogalactic halos will fragment as…

Astrophysics · Physics 2009-06-23 Paul C. Clark , Simon C. O. Glover , Ralf S. Klessen

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

The oscillation feature in primordial power spectrum (PPS), a fingerprint of not only a wide class of models of inflation but new physics, is of significant theoretical interest, and can be imprinted on the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-19 Ze-Yu Peng , Yun-Song Piao

Possible influence of primordial black hole (PBH) evaporations on cosmic microwave background (CMB) is investigated. The spectrum distortions of CMB from the black-body spectrum are described by the chemical potential $\mu$ and the Compton…

Astrophysics · Physics 2008-11-26 Hiroyuki Tashiro , Naoshi Sugiyama

Star formation within the Central Molecular Zone (CMZ) may be intimately linked to the orbital dynamics of the gas. Recent models suggest that star formation within the dust ridge molecular clouds (from G0.253+0.016 to Sgr B2) follows an…

Astrophysics of Galaxies · Physics 2016-10-06 J. D. Henshaw , S. N. Longmore , J. M. D. Kruijssen

The molecular gas content of local early-type galaxies is constrained and discussed in relation to their evolution. First, as part of the Atlas3D survey, we present the first complete, large (260 objects), volume-limited single-dish survey…

The formation of the first stars out of metal-free gas appears to result in stars at least an order of magnitude more massive than in the present-day case. We here consider what controls the transition from a primordial to a modern initial…

Astrophysics · Physics 2011-02-11 A. -K. Jappsen , M. -M. Mac Low , S. C. O. Glover , R. S. Klessen , S. Kitsionas

In the early Universe, energy stored in small-scale density perturbations is quickly dissipated by Silk-damping, a process that inevitably generates mu- and y-type spectral distortions of the cosmic microwave background (CMB). These…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jens Chluba , Adrienne L. Erickcek , Ido Ben-Dayan

The remarkable progress in cosmic microwave background (CMB) studies over past decade has led to the era of precision cosmology in striking agreement with the $\Lambda$CDM model. However, the lack of power in the CMB temperature…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-09 Asif Iqbal , Jayanti Prasad , Tarun Souradeep , Manzoor A. Malik