Inverse Bremsstrahlung in Shocked Astrophysical Plasmas

There has recently been interest in the role of inverse bremsstrahlung, the emission of photons by fast suprathermal ions in collisions with ambient electrons possessing relatively low velocities, in tenuous plasmas in various astrophysical contexts. This follows a long hiatus in the application of suprathermal ion bremsstrahlung to astrophysical models since the early 1970s. The potential importance of inverse bremsstrahlung relative to normal bremsstrahlung, i.e. where ions are at rest, hinges upon the underlying velocity distributions of the interacting species. In this paper, we identify the conditions under which the inverse bremsstrahlung emissivity is significant relative to that for normal bremsstrahlung in shocked astrophysical plasmas. We determine that, since both observational and theoretical evidence favors electron temperatures almost comparable to, and certainly not very deficient relative to proton temperatures in shocked plasmas, these environments generally render inverse bremsstrahlung at best a minor contributor to the overall emission. Hence inverse bremsstrahlung can be safely neglected in most models invoking shock acceleration in discrete sources such as supernova remnants. However, on scales > 100pc distant from these sources, Coulomb collisional losses can deplete the cosmic ray electrons, rendering inverse bremsstrahlung, and perhaps bremsstrahlung from knock-on electrons, possibly detectable.Comment: 13 pages, including 2 figures, using apjgalley format; to appear in the January 10, 2000 issue, of the Astrophysical Journa

Using Gamma-Ray Burst Prompt Emission to Probe Relativistic Shock Acceleration

It is widely accepted that the prompt transient signal in the 10 keV - 10 GeV band from gamma-ray bursts (GRBs) arises from multiple shocks internal to the ultra-relativistic expansion. The detailed understanding of the dissipation and accompanying acceleration at these shocks is a currently topical subject. This paper explores the relationship between GRB prompt emission spectra and the electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The focus is on the array of possible high-energy power-law indices in accelerated populations, highlighting how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. It is emphasized that diffusive shock acceleration theory generates no canonical spectrum at relativistic MHD discontinuities. This diversity is commensurate with the significant range of spectral indices discerned in prompt burst emission. Such system diagnostics are now being enhanced by the broadband spectral coverage of bursts by the Fermi Gamma-Ray Space Telescope; while the Gamma-Ray Burst Monitor (GBM) provides key diagnostics on the lower energy portions of the particle population, the focus here is on constraints in the non-thermal, power-law regime of the particle distribution that are provided by the Large Area Telescope (LAT).Comment: 15 pages, 2 figures. Accepted for publication in Advances of Space Researc

The Contexts of Conversion among U.S. Latinos

The growth of Protestantism among U.S. Latinos has been the focus of considerable discussion among researchers. Yet few studies investigate how Latino Protestants and Latino Catholics differ, or which types of Latinos convert from Catholicism to Protestantism. Our study tests various theories about why some Latinos convert including a modified version of the semi-involuntary thesis, the national origin hypothesis, and assimilation theory. We use data from a large national sample of U.S. Latinos and find some support for assimilation theory and less for the semi-involuntary thesis. However, context matters. If we divide Latinos into national origin groups, these groups strongly predict who converts and who are lifelong Protestants. We discuss how war may influence the religious composition of early migrants and thus shape both the religious composition and conversion of later migrants

Religion and Attitudes toward Same-Sex Marriage among U.S. Latinos

Objectives. This study examines links between multiple aspects of religious involvement and attitudes toward same-sex marriage among U.S. Latinos. The primary focus is on variations by affiliation and participation, but the possible mediating roles of biblical beliefs, clergy cues, and the role of religion in shaping political views are also considered. Methods. We use binary logistic regression models to analyze data from a large nationwide sample of U.S. Latinos conducted by the Pew Hispanic Forum in late 2006. Results. Findings highlight the strong opposition to same-sex marriage among Latino evangelical (or conservative) Protestants and members of sectarian groups (e.g., LDS), even compared with devout Catholics. Although each of the hypothesized mediators is significantly linked with attitudes toward same-sex marriage, for the most part controlling for them does not alter the massive affiliation/attendance differences in attitudes toward same-sex marriage. Conclusions. This study illustrates the importance of religious cleavages in public opinion on social issues within the diverse U.S. Latino population. The significance of religious variations in Hispanic civic life is likely to increase with the growth of the Latino population and the rising numbers of Protestants and sectarians among Latinos

Attitudes toward Marriage, Divorce, Cohabitation, and Casual Sex among Working-Age Latinos: Does Religion Matter?

The rapid growth of the Latino population in the United States has renewed interest in Latino family research. It has often been assumed that Catholicism is a key factor influencing Latinos’ attitudes toward the family, despite the fact that nearly one third of Latinos are not Catholic. This article uses data from the 2006 National Survey of Religion and Family Life, a survey of working-age adults (aged 18-59 years) in the lower 48 states, to explore the relationship between multiple dimensions of religiosity—denomination, church attendance, prayer, and beliefs about the Bible—and Latinos’ attitudes regarding marriage, divorce, cohabitation, and casual sex. Compared with Catholics, evangelical Protestants tend to hold more conservative attitudes on family-related issues. Latinos who attend services regularly and pray frequently also report more traditional views. Findings involving literalist views of the Bible are more equivocal. Taken together, religious variables are just as potent as socioeconomic and demographic factors in explaining individual-level variation in Latinos’ attitudes. Study limitations are noted, and several directions for future research are identified

Faith, Race-Ethnicity, and Public Policy Preferences: Religious Schemas and Abortion Attitudes among U.S. Latinos

Research has demonstrated that white conservative Protestants are more opposed to abortion than their Catholic counterparts. At the same time, conservative Protestantism has made significant inroads among U.S. Latinos. This study augments existing research on religion and racial-ethnic variations in abortion attitudes by comparing levels of support for legalized abortion among Catholic and conservative Protestant Latinos. Data are drawn from a nationally representative sample of U.S. Latinos. Significantly greater opposition to abortion is found among religiously devout conservative Protestant Latinos when compared with their Catholic counterparts. Latino Catholicism, which functions as a near-monopolistic, highly institutionalized faith tradition among Hispanics, produces weaker antiabortion attitudes than those exhibited in Latino conservative Protestantism. Among Latinos, conservative Protestantism operates as a niche voluntaristic faith. These factors produce a religious schema that yields robust antiabortion attitudes. This study has important implications for understanding the intersection of race-ethnicity, religion, and public policy preferences