One of the most puzzling properties of observed galaxies is the universality of the empirical correlation between the star formation rate and average gas surface density on kiloparsec scales (the Schmidt law). In this study I present results of self-consistent cosmological simulations of high-redshift galaxy formation that reproduce the Schmidt law naturally, without assuming it, and provide so...

We present the detection of molecular absorption lines in the optical spectrum of the post-AGB star HD 56126. The C2 Phillips A Πu − X Σg (1,0), (2,0), and (3,0); Swan dΠg − a Πu (0,0) and (1,0); and CN Red system AΠ − XΣ (1,0), (2,0), (3,0), and (4,0) bands have been identified. From the identification of the molecular bands we find an expansion velocity of 8.5 ± 0.6 km s independent of excita...

– As a test of the time-dependent local-density approximation (TDLDA), we study the Σg → Σu excitation of H2 as a function of the nuclear distance d. We find rather accurate results for intermediate d but not for small and large d. At large d, TDLDA fails due to the strong non-locality and energy dependence of the exact functional. The spin-dependent formalism gives a qualitative improvement fo...

Theoretical ab initio calculations are reported of the cross sections for dissociative recombination of the lowest four excited vibrational levels of N2(+) at electron energies from 0.001 to 1.0 eV. Rydberg vibrational levels contributing to the cross section structures are identified as are dissociative channels contributing more than 10(-16) cm(2) to the total cross sections. In contrast to t...

Mod(Σ) = Homeo(Σ)/Homeo0(Σ), where, Homeo(Σ) is the group of orientation preserving homeomorphisms of Σ and Homeo0(Σ) are those homeomorphisms isotopic to the identity. When Σ is a closed surface of genus g ≥ 1 then we denote Mod(Σ) by Γg. In this case it is well-known that Γg is isomorphic to a subgroup of index 2 in Out(π1(Σ)). When g = 1, the subgroup structure of Γ1 is well-understood since...

This short note is a follow-up to (the second part of) Section 7.6 of my book [3]. There, earlier results of N. Dunfield and W. Thurston [1] on a certain type of random 3-manifolds (compact, connected) were improved and were made quantitative, using large-sieve inequalities for random walks on discrete groups. Roughly speaking, these results expressed the fact that “typical” 3-manifolds could b...

For more than 70 years, researchers in several areas of science have been intrigued by the physical and chemical properties of the lowest excited states of molecular oxygen. With two singlet states lying close above its triplet ground state, the O2 molecule possesses a very unique configuration, which gives rise to a very rich and easily accessible chemistry, and also to a number of important p...

The original article written by Lichten, McCusker, and Vierima reported the measurement of the fine structure of the v=0 vibrational state of the a 3 Σu + metastable state of He2 by a molecular beams-magnetic resonance (MBMR) machine from the afterglow of a pulsed helium plasma discharge. By fitting the measured zero field intervals in the N=1 and N=3 rotational levels, the author deduced the s...

has cardinality r ≥ 1. Let G be the F-rational points of a simple Chevalley group defined over F. In his thesis, Matsumoto [5] gave a beautiful construction for the metaplectic cover G̃ of G, a central extension of G by μr(F) whose existence is intimately connected with the deep properties of the r-th order Hilbert symbol (·, ·)F : F × × F → μr(F). Metaplectic groups figure prominently in the st...