Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5 × 10(10) solar masses) of the submillimetre bright galaxies can explain the formation of typical elliptical galaxies, it is inadequate to form elliptical galaxies that already have stellar masses above 2 × 10(11) solar masses at z ≈ 2. Here we report multi-wavelength high-resolution observations of a rare merger of two massive submillimetre bright galaxies at z = 2.3. The system is seen to be forming stars at a rate of 2,000 solar masses per year. The star-formation efficiency is an order of magnitude greater than that of normal galaxies, so the gas reservoir will be exhausted and star formation will be quenched in only around 200 million years. At a projected separation of 19 kiloparsecs, the two massive starbursts are about to merge and form a passive elliptical galaxy with a stellar mass of about 4 × 10(11) solar masses. We conclude that gas-rich major galaxy mergers with intense star formation can form the most massive elliptical galaxies by z ≈ 1.5.
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http://dx.doi.org/10.1038/nature12184 | DOI Listing |
Biosystems
January 2025
Departamento de Estado Sólido, Instituto de Física, Universidad Nacional Autónoma de México, Circuito de la Investigación Científica, Ciudad Universitaria, Ciudad de México, 04510, Mexico.
A prebiotic model, based in the framework of thermodynamic efficiency loss from small dissipative eukaryote organisms is developed to describe the maximum possible concentration of solar power to be dissipated on topological circular molecules structures encapsulated in lipid-walled vacuoles, which floated in the Archean oceans. By considering previously, the analysis of 71 species examined by covering 18 orders of mass magnitude from the Megapteranovaeangliae to Saccharomyces cerevisiae suggest that in molecular structures of smaller masses than any living being known nowadays, the power dissipation must be directly proportional to the power of the photons of solar origin that impinge them to give rise to the formation of more complex self-assembled molecular structures at the prebiotic stage by a quantum mechanics model of resonant photon wavelength excitation. The analysis of 12 circular molecules (encapsulated in lipid-walled vacuoles) relevant to the evolution of life on planet Earth such as the five nucleobases, and some aromatic molecules as pyrimidine, porphyrin, chlorin, coumarin, xanthine, etc.
View Article and Find Full Text PDFHeliyon
November 2024
Grenoble Alpes University, CNRS, Grenoble INP, Néel Institute, 38000, Grenoble, France.
Phys Chem Chem Phys
December 2024
Department of Physics, Sabang Sajanikanta Mahavidyalaya, Lutunia, West Bengal 721166, India.
Nontoxic, stable, and experimentally realized lead-free halide double perovskites, CsAgBiX (X = Br, Cl), attracted much attention for solar cell applications. However, their reduced electronic dimensionality and indirect (wide) bandgap, limiting solar energy absorption efficiency, are not mostly suitable. To address such issues, we employ the computationally efficient DFT-1/2 + SOC method to study the electronic structure of cation-ordered and cation-disordered materials comparatively.
View Article and Find Full Text PDFNature
November 2024
Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
Astronomers have found more than a dozen planets transiting stars that are 10-40 million years old, but younger transiting planets have remained elusive. The lack of such discoveries may be because planets have not fully formed at this age or because our view is blocked by the protoplanetary disk. However, we now know that many outer disks are warped or broken; provided the inner disk is depleted, transiting planets may thus be visible.
View Article and Find Full Text PDFHeliyon
October 2024
Department of Materials Science and Engineering, Khulna University of Engineering & Technology (KUET), Khulna, 9203, Bangladesh.
Here, first-principles calculations have been employed to make a comparative study on structural, mechanical, electronic, and optical properties of new CaMF (M = As and Sb) photovoltaic compounds under pressure. The findings disclose that these two systems possess a direct band gap, showcasing a large tunable range under pressure, effectively encompassing the visible light spectrum. Adjusting various levels of hydrostatic pressure has effectively tuned both the band alignment and the effective masses of electrons and holes.
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