The Disappearing Act of KH 15D: Photometric Results from 1995 to 2004

We present results from the most recent (2002-2004) observing campaigns of the eclipsing system KH 15D, in addition to re-reduced data obtained at Van Vleck Observatory (VVO) between 1995 and 2000. Phasing nine years of photometric data shows substantial evolution in the width and depth of the eclipses. The most recent data indicate that the eclipses are now approximately 24 days in length, or half the orbital period. These results are interpreted and discussed in the context of the recent models for this system put forward by Winn et al. and Chiang & Murray-Clay. A periodogram of the entire data set yields a highly significant peak at 48.37 +/- 0.01 days, which is in accord with the spectroscopic period of 48.38 +/- 0.01 days determined by Johnson et al. Another significant peak, at 9.6 days, was found in the periodogram of the out-of-eclipse data at two different epochs. We interpret this as the rotation period of the visible star and argue that it may be tidally locked in pseudosynchronism with its orbital motion. If so, application of Hut's theory implies that the eccentricity of the orbit is e = 0.65 +/- 0.01. Analysis of the UVES/VLT spectra obtained by Hamilton et al. shows that the v sin(i) of the visible star in this system is 6.9 +/- 0.3 km/sec. Using this value of v sin(i) and the measured rotation period of the star, we calculate the lower limit on the radius to be R = (1.3 +/- 0.1), R_Sun, which concurs with the value obtained by Hamilton et al. from its luminosity and effective temperature. Here we assume that i = 90 degrees since it is likely that the spin and orbital angular momenta vectors are nearly aligned.Comment: 55 pages, 18 figures, 1 color figure, to appear the September issue of the Astronomical Journa

Three (Potential) Pillars of Transnational Economic Justice: The Bretton Woods Institutions as Guarantors of Global Equal Treatment and Market Completion

This essay aims to bring two important lines of inquiry and criticism together. It first lays out an institutionally enriched account of what a just world economic order will look like. That account prescribes, via the requisites to that mechanism which most directly instantiate the account, three realms of equal treatment and market completion - the global products, services, and labor markets; the global investment/financial markets; and the global preparticipation opportunity allocation. The essay then suggests how, with minimal if any departure from familiar canons of traditional international legal mandate interpretation, each of the Bretton Woods institutions - particularly the GATT/WTO and the IMF - can be viewed at least in part as charged with the task of fostering equal treatment and ultimate market completion within one of those three realms. The piece then argues that one of the institutions in particular - the World Bank - has, for reasons of at best negligent and at worst willful injustice on the part of influential state actors in the world community, fallen farthest short in pursuit of what should be viewed as its proper mandate. The article accordingly concludes that a fuller empowerment of the Bank to effect its ideal mission will press the Bretton Woods system more nearly into ethical balance, and with it the world into justice; and that full empowerment of the GATT/WTO and IMF should be partly conditioned upon the fuller empowerment of the Bank

The Astropy Problem

The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software

Dreams and nightmares of liberal international law: capitalist accumulation, natural rights and state hegemony

This article develops a line of theorising the relationship between peace, war and commerce and does so via conceptualising global juridical relations as a site of contestation over questions of economic and social justice. By sketching aspects of a historical interaction between capitalist accumulation, natural rights and state hegemony, the article offers a critical account of the limits of liberal international law, and attempts to recover some ground for thinking about the emancipatory potential of international law more generally

Many Labs 2: Investigating Variation in Replicability Across Samples and Settings

We conducted preregistered replications of 28 classic and contemporary published findings, with protocols that were peer reviewed in advance, to examine variation in effect magnitudes across samples and settings. Each protocol was administered to approximately half of 125 samples that comprised 15,305 participants from 36 countries and territories. Using the conventional criterion of statistical significance (p < .05), we found that 15 (54%) of the replications provided evidence of a statistically significant effect in the same direction as the original finding. With a strict significance criterion (p < .0001), 14 (50%) of the replications still provided such evidence, a reflection of the extremely highpowered design. Seven (25%) of the replications yielded effect sizes larger than the original ones, and 21 (75%) yielded effect sizes smaller than the original ones. The median comparable Cohen’s ds were 0.60 for the original findings and 0.15 for the replications. The effect sizes were small (< 0.20) in 16 of the replications (57%), and 9 effects (32%) were in the direction opposite the direction of the original effect. Across settings, the Q statistic indicated significant heterogeneity in 11 (39%) of the replication effects, and most of those were among the findings with the largest overall effect sizes; only 1 effect that was near zero in the aggregate showed significant heterogeneity according to this measure. Only 1 effect had a tau value greater than .20, an indication of moderate heterogeneity. Eight others had tau values near or slightly above .10, an indication of slight heterogeneity. Moderation tests indicated that very little heterogeneity was attributable to the order in which the tasks were performed or whether the tasks were administered in lab versus online. Exploratory comparisons revealed little heterogeneity between Western, educated, industrialized, rich, and democratic (WEIRD) cultures and less WEIRD cultures (i.e., cultures with relatively high and low WEIRDness scores, respectively). Cumulatively, variability in the observed effect sizes was attributable more to the effect being studied than to the sample or setting in which it was studied.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

The Once and Future Sun

This site describes the evolution of stars like the sun from the collapse of gas and dust to turning into a white dwarf. The life cycle of a star is illustrated through all stages with text and images

Spectroscopy monitoring of active galactic nuclei from CTIO. I. NGC 3227

The results of a five-month monitoring campaign on the Seyfert 1.5 galaxy NGC 3227 are presented. Variability was detected in the continuum and in the broad emission lines. Cross correlations of the 4200 Å continuum light curve with the Hβ and He II λ4686 emission-line light curves indicate delays of 18 ± 5 and 16 ± 2 days, respectively, between the continuum variations and the response of the lines. We apply a maximum entropy method to solve for the transfer function that relates the Hβ and He II λ4686 lines and 4200 Å continuum variability and the result of this analysis suggests that there is a deficit of emission-line response due to gas along the line of sight to the continuum source for both lines. Using a composite off-nuclear spectrum, we synthesize the bulge stellar population, which is found to be mainly old (77% with age > 10 Gyr) with a metallicity twice the solar value. The synthesis also yields an internal color excess E(B−V) ≈0.04. The mean contribution of the stellar population to the inner 5" x 10" spectra during the campaign was ~40%

Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XIV. Intensive Optical Spectrophotometric Observations of NGC 7469

We present results of an intensive 2 month campaign of ground-based spectrophotometric monitoring of the Seyfert 1 galaxy NGC 7469, with a temporal resolution [approximately less than]1 day. The broad Hα and Hβ emission lines respond to ~35% ultraviolet continuum variations with an amplitude of ~10% and time delays of 5.6±1.3 days and 5.4±0.8 days, respectively. We interpret this as evidence of variable Balmer line gas ~5-6 light days from the central source in this object, widely believed to be a supermassive black hole. The virial mass of the central source implied by line widths and time delays is ~106-107 M◉ Concomitantly, we find evidence for wavelength-dependent continuum time delays : optical continuum variations lag those at 1315 Å by 1.0±0.3 days at 4865 Å to 1.5±0.7 days at 6962 Å. . This suggests a stratified continuum reprocessing region extending several light days from the central source, possibly an accretion disk