Why Limits on Contributions to Super PACs Should Survive \u3ci\u3eCitizens United\u3c/i\u3e

Soon after the Supreme Court decided Citizens United v. FEC, the D.C. Circuit held all limits on contributions to super PACs unconstitutional. Its decision in SpeechNow.org v. FEC created a regime in which contributions to candidates are limited but in which contributions to less responsible groups urging votes for these candidates are unbounded. No legislator voted for this system of campaign financing, and the judgment that the Constitution requires it is astonishing. Forty-two years ago, Buckley v. Valeo held that Congress could limit contributions to candidates because these contributions are corrupting or create an appearance of corruption. According to the D.C. Circuit, however, Congress may not prohibit multi-million-dollar contributions to satellite campaigns because these contributions do not create even an appearance of corruption. The D.C. Circuit said that a single sentence of the Citizens United opinion compelled its result. It wrote, “In light of the Court’s holding as a matter of law that independent expenditures do not corrupt or create the appearance of corruption, contributions to groups that make only independent expenditures also cannot corrupt or create the appearance of corruption.” This Article contends that, contrary to the D.C. Circuit’s reasoning, contributions to super PACs can corrupt even when expenditures by these groups do not. Moreover, the statement that the D.C. Circuit took as its premise was dictum, and the Supreme Court did not mean this statement to be taken in the way the D.C. Circuit took it. The Supreme Court’s long-standing distinction between contribution limits and expenditure limits does not rest on the untenable proposition thatcandidates cannot be corrupted by funds paid to and spent on their behalf by others. Rather, Buckley noted five differences between contributions and expenditures. A review of these differences makes clear that contributions to super PACs cannot be distinguished from the contributions to candidates whose limitation the Court upheld. The ultimate question posed by Buckley is whether super PAC contributions create a sufficient appearance of corruption to justify their limitation. This Article reviews the statements of candidates of both parties in the 2016 presidential election, the views of Washington insiders, and public opinion polls. It shows that SpeechNow has sharpened class divisions and helped to tear America apart. The Justice Department did not seek Supreme Court review of the SpeechNow decision. In a statement that belongs on a historic list of wrong predictions, Attorney General Holder explained that the decision would “affect only a small subset of federally regulated contributions.” Although eight years have passed since SpeechNow, the Supreme Court has not decided whether the Constitution guarantees the right to give unlimited funds to super PACs. A final section of this Article describes the efforts of members of Congress and candidates for Congress to bring that question before the Court. The Federal Election Commission is opposing their efforts, offering arguments that, if accepted, would be likely to keep the Court from ever deciding the issue

Qualitative and quantitative analysis of mixtures of compounds containing both hydrogen and deuterium

Method allows qualitative and quantitative analysis of mixtures of partially deuterated compounds. Nuclear magnetic resonance spectroscopy determines location and amount of deuterium in organic compounds but not fully deuterated compounds. Mass spectroscopy can detect fully deuterated species but not the location

How the First Stars Regulated Local Star Formation I: Radiative Feedback

We present numerical simulations of how a 120 M$_\odot$ primordial star regulates star formation in nearby cosmological halos at $z \sim$ 20 by photoevaporation. Our models include nine-species primordial chemistry and self-consistent multifrequency conservative transfer of UV photons with all relevant radiative processes. Whether or not new stars form in halos clustered around a Population III star ultimately depends on their core densities and proximity to the star. Diffuse halos with central densities below 2 - 3 cm$^{-3}$ are completely ionized and evaporated anywhere in the cluster. Evolved halos with core densities above 2000 cm$^{-3}$ are impervious to both ionizing and Lyman-Werner flux at most distances from the star and collapse as quickly as they would in its absence. Star formation in halos of intermediate density can be either promoted or suppressed depending on how the I-front remnant shock compresses, deforms and enriches the core with H$_2$. We find that the 120 M$_\odot$ star photodissociates H$_2$ in most halos in the cluster but that catalysis by H- restores it a few hundred kyr after the death of the star, with little effect on star formation. Our models exhibit significant departures from previous one-dimensional spherically-symmetric simulations, which are prone to serious errors due to unphysical geometric focusing effects.Comment: 20 pages, 19 figures, accepted by ApJ, title and abstract change

Photoionization of Clustered Halos by the First Stars

We present numerical simulations of the photoevaporation of cosmological halos clustered around a 120 M$_\odot$ primordial star, confining our study to structures capable of hosting Population III star formation. The calculations include self-consistent multifrequency conservative transfer of UV photons together with nine-species primordial chemistry and all relevant radiative processes. The ultimate fates of these halos varies with central density and proximity to the central source but generally fall into one of four categories. Diffuse halos with central densities below 2 - 3 cm$^{-3}$ are completely ionized and evaporated by the central star anywhere in the cluster. More evolved halo cores at densities above 2000 cm$^{-3}$ are impervious to both ionizing and Lyman-Werner flux at most distances from the star and collapse of their cores proceeds without delay. Radiative feedback in halos of intermediate density can be either positive or negative, depending on how the I-front remnant shock both compresses and deforms the core and enriches it with H$_2$. We find that the 120 M$_\odot$ star photodissociates H$_2$ in most halos within the cluster but that catalysis by H- rapidly restores molecular hydrogen within a few hundred Kyr after the death of the star, with little delay in star formation. Our models exhibit significant departures from previous one-dimensional spherically-symmetric simulations, which are prone to serious errors due to unphysical geometric focusing effects.Comment: 5 pages, 5 figures, to appear in "First Stars III", eds. B. O'Shea, A. Heger and T. Abe

Population III star formation in a Lambda CDM universe, II: Effects of a photodissociating background

We examine aspects of primordial star formation in the presence of a molecular hydrogen-dissociating ultraviolet background. We compare a set of AMR hydrodynamic cosmological simulations using a single cosmological realization but with a range of ultraviolet background strengths in the Lyman-Werner band. This allows us to study the effects of Lyman-Werner radiation on suppressing H2 cooling at low densities as well as the high-density evolution of the collapsing core in a self-consistent cosmological framework. We find that the addition of a photodissociating background results in a delay of the collapse of high density gas at the center of the most massive halo in the simulation and, as a result, an increase in the virial mass of this halo at the onset of baryon collapse. We find that, contrary to previous results, Population III star formation is not suppressed for J$_{21} \geq 0.1$, but occurs even with backgrounds as high as J$_{21} = 1$. We find that H2 cooling leads to collapse despite the depressed core molecular hydrogen fractions due to the elevated H2 cooling rates at $T=2-5 \times 10^3$ K. We observe a relationship between the strength of the photodissociating background and the rate of accretion onto the evolving protostellar cloud core, with higher LW background fluxes resulting in higher accretion rates. Finally, we find that the collapsing halo cores in our simulations do not fragment at densities below $n \sim 10^{10}$ cm$^{-3}$ regardless of the strength of the LW background, suggesting that Population III stars forming in halos with T$_{vir} \sim 10^4$ K may still form in isolation.Comment: 46 pages, 14 figures (9 color). Accepted by the Astrophysical Journal, some minor revision

Did Massive Primordial Stars Preenrich the Lyman Alpha Forest?

We examine the dynamical evolution and statistical properties of the supernova ejecta of massive primordial stars in a cosmological framework to determine whether this first population of stars could have enriched the universe to the levels and dispersions seen by the most recent observations of the Lyman-Alpha forest. We evolve a lambda CDM model in a 1 Mpc^3 volume to a redshift of z = 15 and add ``bubbles'' of metal corresponding to the supernova ejecta of the first generation of massive stars in all dark matter halos with masses greater than 5 times 10^5 solar masses. These initial conditions are then evolved to z = 3 and the distribution and levels of metals are compared to observations. In the absence of further star formation the primordial metal is initially contained in halos and filaments. Photoevaporation of metal-enriched gas due to the metagalactic ultraviolet background radiation at the epoch of reionization (z ~ 6) causes a sharp increase of the metal volume filling factor. At z = 3, ~ 2.5% of the simulation volume (approx. 20% of the total gas mass) is filled with gas enriched above a metallicity of 10^-4 Z_solar, and less than 0.6% of the volume is enriched above a metallicity of 10^-3 Z_solar. This suggests that, even with the most optimistic prescription for placement of primordial supernova and the amount of metals produced by each supernova, this population of stars cannot entirely be responsible for the enrichment of the Lyman-$\alpha$ forest to the levels and dispersions seen by current observations unless we have severely underestimated the duration of the Pop III epoch. However, comparison to observations show that Pop III supernovae can be significant contributors to the very low overdensity Lyman-Alpha forest.Comment: 4 pages, 3 figures (color). Accepted to ApJ Letters. Replaced version has some correction

Late Pop III Star Formation During the Epoch of Reionization: Results from the Renaissance Simulations

We present results on the formation of Pop III stars at redshift 7.6 from the Renaissance Simulations, a suite of extremely high-resolution and physics-rich radiation transport hydrodynamics cosmological adaptive-mesh refinement simulations of high redshift galaxy formation performed on the Blue Waters supercomputer. In a survey volume of about 220 comoving Mpc$^3$, we found 14 Pop III galaxies with recent star formation. The surprisingly late formation of Pop III stars is possible due to two factors: (i) the metal enrichment process is local and slow, leaving plenty of pristine gas to exist in the vast volume; and (ii) strong Lyman-Werner radiation from vigorous metal-enriched star formation in early galaxies suppresses Pop III formation in ("not so") small primordial halos with mass less than $\sim$ 3 $\times$ 10$^7$ M$_\odot$. We quantify the properties of these Pop III galaxies and their Pop III star formation environments. We look for analogues to the recently discovered luminous Ly $\alpha$ emitter CR7 (Sobral et al. 2015), which has been interpreted as a Pop III star cluster within or near a metal-enriched star forming galaxy. We find and discuss a system similar to this in some respects, however the Pop III star cluster is far less massive and luminous than CR7 is inferred to be.Comment: 8 pages, 4 figures, 3 tables. Accepted by Ap

Production and processing of Cu-Cr-Nb alloys

A new Cu-based alloy possessing high strength, high conductivity, and good stability at elevated temperatures was recently produced. This paper details the melting of the master alloys, production of rapidly solidified ribbon, and processing of the ribbon to sheet by hot pressing and hot rolling

Population III Star Formation in a Lambda WDM Universe

In this paper we examine aspects of primordial star formation in a gravitino warm dark matter universe with a cosmological constant. We compare a set of simulations using a single cosmological realization but with a wide range of warm dark matter particle masses which have not yet been conclusively ruled out by observations. The addition of a warm dark matter component to the initial power spectrum results in a delay in the collapse of high density gas at the center of the most massive halo in the simulation and, as a result, an increase in the virial mass of this halo at the onset of baryon collapse. Both of these effects become more pronounced as the warm dark matter particle mass becomes smaller. A cosmology using a gravitino warm dark matter power spectrum assuming a particle mass of m_{WDM} ~ 40keV is effectively indistinguishable from the cold dark matter case, whereas the m_{WDM} ~ 15 keV case delays star formation by approx. 10^8 years. There is remarkably little scatter between simulations in the final properties of the primordial protostar which forms at the center of the halo, possibly due to the overall low rate of halo mergers which is a result of the WDM power spectrum. The detailed evolution of the collapsing halo core in two representative WDM cosmologies is described. At low densities (n_{b} <= 10^5 cm^{-3}), the evolution of the two calculations is qualitatively similar, but occurs on significantly different timescales, with the halo in the lower particle mass calculation taking much longer to evolve over the same density range and reach runaway collapse. Once the gas in the center of the halo reaches relatively high densities (n_{b} >= 10^5 cm^{-3}) the overall evolution is essentially identical in the two calculations.Comment: 36 pages, 12 figures (3 color). Astrophysical Journal, accepte

Probing The Ultraviolet Luminosity Function of the Earliest Galaxies with the Renaissance Simulations

In this paper, we present the first results from the Renaissance Simulations, a suite of extremely high-resolution and physics-rich AMR calculations of high redshift galaxy formation performed on the Blue Waters supercomputer. These simulations contain hundreds of well-resolved galaxies at $z \sim 25-8$, and make several novel, testable predictions. Most critically, we show that the ultraviolet luminosity function of our simulated galaxies is consistent with observations of high-z galaxy populations at the bright end of the luminosity function (M$_{1600} \leq -17$), but at lower luminosities is essentially flat rather than rising steeply, as has been inferred by Schechter function fits to high-z observations, and has a clearly-defined lower limit in UV luminosity. This behavior of the luminosity function is due to two factors: (i) the strong dependence of the star formation rate on halo virial mass in our simulated galaxy population, with lower-mass halos having systematically lower star formation rates and thus lower UV luminosities; and (ii) the fact that halos with virial masses below $\simeq 2 \times 10^8$ M$_\odot$ do not universally contain stars, with the fraction of halos containing stars dropping to zero at $\simeq 7 \times 10^6$ M$_\odot$. Finally, we show that the brightest of our simulated galaxies may be visible to current and future ultra-deep space-based surveys, particularly if lensed regions are chosen for observation.Comment: 7 pages, 4 figures, accepted by The Astrophysical Journal Letter