What Divides, and What Unites, Right-Node Raising

We argue, following Barros and Vicente (2011), that right-node raising (RNR) results from either ellipsis or multidominance. Four considerations support this claim. (i) RNR has properties of el- lipsis and of multidominance. (ii) Where these are combined, the structure results from repeated RNR: a pivot created through ellipsis contains a right-peripheral secondary pivot created through multidominance. (iii) In certain circumstances, one or the other derivation is blocked, so that RNR behaves like pure ellipsis or pure multidominance. (iv) Linearization of RNR-as-mul- tidominance requires pruning. The same pruning operation delivers RNR-as-ellipsis, which ex- plains why the two derivations must meet the same ordering constraints

The Fundamental Plane of Damped Lyα Systems

Using a sample of 100 H I-selected damped Lyα (DLA) systems, observed with the High Resolution Echelle Spectrometer on the Keck I telescope, we present evidence that the scatter in the well-studied correlation between the redshift and metallicity of a DLA is largely due to the existence of a mass-metallicity relationship at each redshift. To describe the fundamental relations that exist between redshift, metallicity, and mass, we use a fundamental plane description, which is described by the following equation: [M/H] = (– 1.9 ± 0.5) + (0.74 ± 0.21) centerdot logΔv_90 – (0.32 ± 0.06) centerdot z. Here, we assert that the velocity width, Δv_90, which is defined as the velocity interval containing 90% of the integrated optical depth, traces the mass of the underlying dark matter halo. This description provides two significant improvements over the individual descriptions of the mass-metallicity correlation and metallicity-redshift correlation. Firstly, the fundamental equation reduces the scatter around both relationships by about 20%, providing a more stringent constraint on numerical simulations modeling DLAs. Secondly, it confirms that the dark matter halos that host DLAs satisfy a mass-metallicity relationship at each redshift between redshifts 2 through 5