Attractiveness, Education and Marriage Market Outcomes

This dissertation studies the interrelationship among attractiveness, education and marriage market outcomes. In Section 2, I first examine individuals attractiveness in four dimensions: anthropometric measures (e.g. height and BMI), physical attractiveness, personality attractiveness and grooming, using a unique data set called Add Health. I find that height has positive effects on men's perceived physical attractiveness, but no significant non-zero effects on women. A higher BMI decreases an individual's physical attractiveness on average. However, if the square of BMI is considered, it is shown that thinner women, and stronger men have higher ratings of physical attractiveness. Physical attractiveness, personality attractiveness and grooming are positively correlated with each other. Then I studied how the four attractiveness measures affect peoples socioeconomic outcomes simultaneously. I find that, with all dimensions of attractiveness considered, physical attractiveness still has significant effects on individuals' earnings and spouses' education. Finally, I investigate the source of the penalty and premia of grooming in the labor market. The DID model provides some evidence that there exists general employer discrimination against bad looks. Section 3 studies pre-marital education investment strategies developed by heterogeneous individuals. People with different attributes or marriage incentives form different marriage prospects when making their college decisions, which leads to distinct investment strategies. Overall, people with lower abilities are less likely to go to college than their high-ability cohorts. Low-ability individuals who value current wealth and expected future earnings in a relationship (“marrying-for-money” type) are more likely to go to college than their cohorts who prefer desirable attributes or matching qualities (“marrying-for-love” type). Empirically, this paper adopts the mixture density model to capture the unobserved types of marriage incentives. Data from National Longitudinal Study of Adolescent Health provides supportive evidence. It is estimated that there are over 60 percent of people who belong to the “marrying-for-money” type in the sample. The “marrying-for-love” type of people have higher percentages of attending college on average

A search for pulsations from the compact object of GRB 060218

A fraction of massive stars are expected to collapse into compact objects (accreting black holes or rapidly rotating neutron stars) that successfully produce gamma-ray bursts (GRBs). We examine the possibility of directly observing these gamma-ray burst compact objects (GCOs) using post-explosion observations of past and future GRB sites. In particular, we present a search for early pulsations from the nearby (z=0.0335) gamma-ray burst GRB 060218, which exhibited features possibly consistent with a rapidly spinning neutron star as its underlying GCO. We also consider alternative techniques that could potentially achieve a detection of GCOs either in the Local Volume or near the plane of our own Galaxy.Comment: 4 pages, 3 figures. Revised version, accepted for publication in Astronomy and Astrophysic

The Correlated Multi-color Optical Variations of BL Lac Object S5 0716+714

S5 0716+714 is a well-studied BL Lac object in the sky. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate the emission processes. To examine the possible existence of a lag between variations in different optical bands on this source, we employ a discrete correlation function (DCF) analysis on the light curves. In order to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties, we perform Monte Carlo simulations called "flux redistribution/random subset selection" (FR/RSS). Our analysis confirms that the variations in different optical light curves are strongly correlated. The time lags show a hint of the variations in high frequency band leading those in low frequency band of the order of a few minutes.Comment: 6 pages, 5 figures, 3 tables. This paper has been accepted for publication in PASA

On the Gamma Ray Burst Origin of Extremely Energetic Cosmic Rays

Air shower experiments have detected cosmic ray events of energies upto 300 EeV. Most likely these cosmic rays have originated from compact objects. Their exact sources are yet to be identified. It has been suggested before that gamma ray bursts are possible sources of ultra-high energy cosmic rays. The two models of gamma ray burst emissions most often discussed are the internal and external shock models. We have calculated the proton spectrum above 60EeV from all gamma ray bursts distributed upto a redshift of 0.02 in the internal shock model assuming redshift and luminosity distributions consistent with observations, log normal distributions for their values of Lorentz factors, variability times and duration of bursts. Within the external shock model we have calculated the proton flux above 60EeV from all nearby gamma ray bursts assuming log normal distributions in their values of total energies, Lorentz factors at the deceleration epoch and compared with the observed data. We find that gamma ray bursts can produce cosmic ray proton flux comparable to the flux observed by the Pierre Auger experiment both within the internal and external shock models. We have also studied the dependence of the maximum proton energies and the cooling breaks in the proton spectrum on the various parameters like Lorentz factor, energy of the GRB fireball, variability time (in case of internal shocks), ambient particle density (in case of external shocks). Our results are important to understand how the various observable parameters determine which mechanism e.g. $p\gamma$ interactions, synchrotron cooling of protons will dominate over one another inside these sources.Comment: 16pages,8figures. version accepted in Astroparticle Physic

Rapid X-ray Variability of the BL Lacertae Object PKS 2155-304

(Abridged) We present a detailed power density spectrum and cross-correlation analysis of the X-ray light curves of the BL Lac object PKS 2155-304, observed with BeppoSAX in 1997 and 1996, aimed at exploring the rapid variability properties and the inter-band cross correlations in the X-rays. We also perform the same analysis on the (archival) X-ray light curve obtained with ASCA in 1994.Comment: 47 pages, 11 figures, AAS Latex macros V4.0, accepted for publication in the Astrophysical Journa