Constraining the formation of black-holes in short-period Black-Hole Low-Mass X-ray Binaries

The formation of stellar mass black holes is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova event (if any) and the magnitude of the natal kick the black hole receives at birth (if any). Repetto et al. (2012), studying the position of Galactic X-ray binaries containing black holes, found evidence for black holes receiving high natal kicks at birth. In this Paper we extend that study, taking into account the previous binary evolution of the sources as well. The seven short-period black-hole X-ray binaries that we use, are compact binaries consisting of a low-mass star orbiting a black hole in a period less than $1$ day. We trace their binary evolution backwards in time, from the current observed state of mass-transfer, to the moment the black hole was formed, and we add the extra information on the kinematics of the binaries. We find that several systems could be explained by no natal kick, just mass ejection, while for two systems (and possibly more) a high kick is required. So unless the latter have an alternative formation, such as within a globular cluster, we conclude that at least some black holes get high kicks. This challenges the standard picture that black hole kicks would be scaled down from neutron star kicks. Furthermore, we find that five systems could have formed with a non-zero natal kick but zero mass ejected (i.e. no supernova) at formation, as predicted by neutrino-driven natal kicks.Comment: 15 pages, 14 figures, accepted for publication in MNRA

Micro Efficiency and Aggregate Growth in Chile

Using plant-level data on Chilean manufacturing firms for the 1980-2001 period, we estimate and characterize disaggregate total factor productivity. We use these estimates to study the microeconomic sources of aggregate efficiency, a fundamental part of aPlant dynamics, total factor productivity, growth, chilean manufacturing

Climate Change and Damage from Extreme Weather Events

The risks of extreme weather events are typically being estimated, by federal agencies and others, with historical frequency data assumed to reflect future probabilities. These estimates may not yet have adequately factored in the effects of past and future climate change, despite strong evidence of a changing climate. They have relied on historical data stretching back as far as fifty or a hundred years that may be increasingly unrepresentative of future conditions. Government and private organizations that use these risk assessments in designing programs and projects with long expected lifetimes may therefore be investing too little to make existing and newly constructed infrastructure resistant to the effects of changing climate. New investments designed to these historical risk standards may suffer excess damages and poor returns. This paper illustrates the issue with an economic analysis of the risks of relatively intense hurricanes striking the New York City region.climate; global warming; natural disasters; risk; adaptation

The Dynamics of Earnings in Chile

This paper provides an empirical analysis of individual earnings using data from the Encuesta Suplementaria de Ingresos. We find that the predictable component of income is hump-shaped over the life-cycle, and that there are strong education effects. The unpredictable component of income can be described by a very persistent permanent shock and a transitory shock. Our estimates are built from a panel of cohorts, so we use US data from the PSID to provide a magnitude for the underestimation of the estimated variances. Surprisingly, we find that the variance of the permanent shock is almost 4 times smaller in Chile than in the US, a result, perhaps, of the relative rigidity of the Chilean labor marketEarnings dynamics, income uncertainty

Investigating stellar-mass black hole kicks

We investigate whether stellar-mass black holes have to receive natal kicks in order to explain the observed distribution of low-mass X-ray binaries containing black holes within our Galaxy. Such binaries are the product of binary evolution, where the massive primary has exploded forming a stellar-mass black hole, probably after a common envelope phase where the system contracted down to separations of order 10-30 Rsun. We perform population synthesis calculations of these binaries, applying both kicks due to supernova mass-loss and natal kicks to the newly-formed black hole. We then integrate the trajectories of the binary systems within the Galactic potential. We find that natal kicks are in fact necessary to reach the large distances above the Galactic plane achieved by some binaries. Further, we find that the distribution of natal kicks would seem to be similar to that of neutron stars, rather than one where the kick velocities are reduced by the ratio of black hole to neutron-star mass (i.e. where the kicks have the same momentum). This result is somewhat surprising; in many pictures of stellar-mass black-hole formation, one might have expected black holes to receive kicks having the same momentum (rather than the same speed) as those given to neutron stars.Comment: 13 pages, 8 figures, 4 tables. Accepted for publication in MNRA

Slow Recoveries

Economies respond differently to aggregate shocks that reduce output. While some countries rapidly recover their pre-crisis trend, others stagnate. Recent studies provide empirical support for a link between aggregate growth and plant dynamics through its effect on productivity: the entry and exit of firms and the reallocation of resources from less to more efficient firms explain a relevant part of transitional productivity dynamics. In this paper we use a stochastic general equilibrium model with heterogeneous firms to study the effect on aggregate short-run growth of policies that distort the process of birth, growth and death of firms, as well as the reallocation of resources across economic units. Our findings show that indeed policies that alter plant dynamics can explain slow recoveries. We also find that output losses associated to delayed recoveries are large.

Market Reforms and Efficiency Gains in Chile

Starting in the mid 1970s, Chile implemented a deep and comprehensive set of structural market reforms. In spite of the wide agreement there is with respect to the benefits these reforms should have on growth, little evidence has been provided to empirically establish and to quantify this connection. Using plant-level data on Chilean manufacturing firms for the 1980-2001 period, we provide suggestive evidence of the role of structural reforms on plant efficiency. The paper first analyzes the behavior of aggregate total factor productivity constructed from data at the plant-level. We find that, once major reforms had been fully implemented, aggregate efficiency gains were explained in equal proportions by within plant improvements and by the net entry of new and more productive economic units. The reallocation among incumbent plants did not contribute significantly to the enhancement of efficiency. The paper also finds that within-plant efficiency gains were the largest among firms producing traded goods, and among firms that were more likely to face binding liquidity constraints. Thus, in Chile, the adoption of better technologies and production processes, fostered by broader foreign exposure and a superior access to external finance, seem to have at least partially accounted for the observed improvement in manufacturing performance.