ABSTRACT The primary Kepler Mission provided nearly continuous monitoring of ∼200,000 objects with unprecedented photometric precision. We present the final catalog of eclipsing binary systems within the 105 deg2 Kepler field of view. This release incorporates the full extent of the data from the primary mission (Q0-Q17 Data Release). As a result, new systems have been added, additional false positives have been removed, ephemerides and principal parameters have been recomputed, classifications have been revised to rely on analytical models, and eclipse timing variations have been computed for each system. We identify several classes of systems including those that exhibit tertiary eclipse events, systems that show clear evidence of additional bodies, heartbeat systems, systems with changing eclipse depths, and systems exhibiting only one eclipse event over the duration of the mission. We have updated the period and galactic latitude distribution diagrams and included a catalog completeness evaluation. The total number of identified eclipsing and ellipsoidal binary systems in the Kepler field of view has increased to 2878, 1.3% of all observed Kepler targets. An online version of this catalog with downloadable content and visualization tools is maintained at http://keplerEBs.villanova.edu.

We present the first results of a project aiming to trace the spatial structure of the Milky Way using detached eclipsing binaries (DEBs) as distance indicators. A sample of DEBs from the OGLE-II catalogue was selected and their near infrared photometry was taken from the Vista Variables in the Via Lactea (VVV) survey. The I band OGLE-II light curves are used to create models of the DEBs, which together with the VVV photometry are compared with a set of theoretical isochrones. After correcting for stellar reddening, we find a set of absolute physical parameters of components of a given binary, including absolute magnitudes and distances. With this approach we can calculate the distances with the precision better than 5 per cent. Even though we have a few systems, the distribution is not homogeneous along the line of sight, and appears to follow the overall structure of the Galaxy - several spiral arms and the Bulge are distinguishable. A number of systems can be seen behind the Bulge, reaching even the distance to the Sagittarius dwarf galaxy.

In recent years, we have witnessed an explosion of photometric time-series data, collected for the purpose of finding a small number of rare sources, such as transiting extrasolar planets and gravitational microlenses. Once combed, these data are often set aside, and are not further searched for the many other variable sources that they undoubtedly contain. To this end, we describe a pipeline that is designed to systematically analyze such data, while requiring minimal user interaction. We ran our pipeline on a subset of the Trans-Atlantic Exoplanet Survey dataset, and used it to identify and model 773 eclipsing binary systems. For each system we conducted a joint analysis of its light curve, colors, and theoretical isochrones. This analysis provided us with estimates of the binary's absolute physical properties, including the masses and ages of their stellar components, as well as their physical separations and distances. We identified three types of eclipsing binaries that are of particular interest and merit further observations. The first category includes 11 low-mass candidates, which may assist current efforts to explain the discrepancies between the observation and the models of stars at the bottom of the main sequence. The other two categories include 34 binaries with eccentric orbits, and 20 binaries with abnormal light curves. Finally, this uniform catalog enabled us to identify a number of relations that provide further constraints on binary population models and tidal circularization theory.

We describe the discovery of a 0.68+0.52 M☉ eclipsing binary (EB) with an 8.4 day orbital period, found through a systematic search of 10 fields of the Trans-atlantic Exoplanet Survey (TrES). Such long-period low-mass EBs constitute critical test cases for resolving the long-standing discrepancy between the theoretical and observational mass-radius relations at the bottom of the main sequence. It has been suggested that this discrepancy may be related to strong stellar magnetic fields, which are not properly accounted for in current theoretical models. All previously well-characterized low-mass main-sequence EBs have periods of a few days or less, and their components are therefore expected to be rotating rapidly as a result of tidal synchronization, thus generating strong magnetic fields. In contrast, the binary system described here has a period that is more than 3 times longer than previously characterized low-mass main-sequence EBs, and its components rotate relatively slowly. It is therefore expected to have a weaker magnetic field and to better match the assumptions of theoretical stellar models. Our follow-up observations of this EB yield preliminary stellar properties that suggest it is indeed consistent with current models. If further observations confirm a low level of activity in this system, these determinations would provide support for the hypothesis that the mass-radius discrepancy is at least partly due to magnetic activity.

Eclipsing binary star systems provide the most accurate method of measuring both the masses and radii of stars. Moreover, they enable testing tidal synchronization and circularization theories, as well as constraining models of stellar structure and dynamics. With the recent availability of large-scale multi-epoch photometric datasets we were able to study eclipsing binary stars en masse. In this thesis, we analyzed 185,445 light curves from ten TrES fields, and 218,699 light curves from the OGLE II bulge fields. In order to manage such large quantities of data, we developed a pipeline with which we systematically identified eclipsing binaries, solved for their geometric orientations, and then found their components' absolute properties. Following this analysis we assembled catalogs of eclipsing binaries with their models, computed statistical distributions of their properties, and located rare cases for further follow-up, including T-Cyg1-03378, which has unusual eclipse timing variations. Of particular importance are low-mass eclipsing binaries, which are rare yet critical for resolving the ongoing mass-radius discrepancy between theoretical models and observations. To this end, we have discovered over a dozen new low-mass eclipsing binary candidates and spectroscopically confirmed the masses of five of them. One of these confirmed candidates, T-Lyr1-17236, is especially interesting because of its long orbital period. We examined T-Lyr1-17236 in detail and found that it is consistent with the magnetic disruption hypothesis. Both the source code of our pipeline and the complete list of our candidates are freely available.

We describe the Method for Eclipsing Component Identification (MECI), which is an automated method for assigning the most likely absolute physical parameters to the components of an eclipsing binary. MECI is unique in that it requires only the photometric light curve and combined color of the eclipsing binaries. We have implemented this method using published theoretical isochrones and limb-darkening coefficients, and publicly released its source code*. MECI lends itself to creating large catalogues through the systematic analyses of datasets consisting of photometric time series, such as those produced by OGLE, MACHO, HAT, and many others surveys. We will be presenting results of data mining the Trans-Atlantic Exoplanet Survey (TrES). This sort of mining technique may be used for both characterizing stellar populations and for discovering rare and interesting binary systems. Of particular interest are the lower main-sequence stars, for which models underestimate their sizes by as much as 20%. Progress in this area has been hampered by the small number of suitable M-dwarf binary systems with accurately determined stellar properties. Finding additional systems by mining Exoplanet Surveys may provide significant benefits for our understanding of such low-mass stars.

The Method for Eclipsing Component Identification (MECI) is an automated method for assigning the most likely absolute physical parameters to the components of an eclipsing binary (EB) star system. MECI is unique in that it requires only the photometric light curve and combined colors of an eclipsing binary star system. This method enables us to systematically analyze large photometric time-series survey datasets (e.g. OGLE, MACHO, TrES, HAT, and many others). It also enables the analysis of binaries that are faint due to their large distance or low intrinsic luminosity, for which obtaining multi-epoch spectroscopy would be difficult. We built an automated implementation of this method and publicly released its source code(1). We intend to use MECI to find rare and interesting systems, specifically low-mass binaries, for which the mass-radius relation is poorly understood.

We describe an automated method for assigning the most likely physical parameters to the components of an eclipsing binary (EB), using only its photometric light curve and combined color. In traditional methods (e.g. WD and EBOP) one attempts to optimize a multi-parameter model over many iterations, so as to minimize the chi-squared value. We suggest an alternative method, where one selects pairs of coeval stars from a set of theoretical stellar models, and compares their simulated light curves and combined colors with the observations. This approach greatly reduces the EB parameter-space over which one needs to search, and allows one to determine the components' masses, radii and absolute magnitudes, without spectroscopic data. We have implemented this method in an automated program using published theoretical isochrones and limb-darkening coefficients. Since it is easy to automate, this method lends itself to systematic analyses of datasets consisting of photometric time series of large numbers of stars, such as those produced by OGLE, MACHO, TrES, HAT, and many others surveys.

We have undertaken a long-term project, Planets in Stellar Clusters Extensive Search (PISCES), to search for transiting planets in open clusters. In this paper we present the results for NGC 6791, a very old, populous, metal-rich cluster. We have monitored the cluster for over 300 hr, spread over 84 nights. We have not detected any good transiting planet candidates. Given the photometric precision and temporal coverage of our observations and the current best estimates for the frequency and radii of short-period planets, the expected number of detectable transiting planets in our sample is 1.5. We have discovered 14 new variable stars in the cluster, most of which are eclipsing binaries, and present high-precision light curves spanning 2 years for these new variables and also the previously known variables.

We have developed a fully automated pipeline for systematically identifying and analyzing eclipsing binaries within large data sets of light curves. The pipeline is made up of multiple tiers that subject the light curves to increasing levels of scrutiny. After each tier, light curves that did not conform to a given criteria were filtered out of the pipeline, reducing the load on the following, more computationally intensive tiers. As a central component of the pipeline, we created the fully automated Detached Eclipsing Binary Light curve fitter (DEBiL), which rapidly fits large numbers of light curves to a simple model. Using the results of DEBiL, light curves of interest can be flagged for follow-up analysis. As a test case, we analyzed the 218,699 light curves within the bulge fields of the OGLE II survey and produced 10,862 model fits. We point out a small number of extreme examples, as well as unexpected structure found in several of the population distributions. We expect this approach to become increasingly important as light-curve data sets continue growing in both size and number.

We explain in simple terms how the build-up of dark haloes by merging compact satellites, as in the cold dark matter (CDM) cosmology, inevitably leads to an inner cusp of density profile rho proportional to r(-alpha) with alphagreater than or similar to 1, as seen in cosmological N -body simulations. A flatter halo core with alpha < 1 exerts on the satellites tidal compression in all directions, which prevents the deposit of stripped satellite material in the core region. This makes the satellite orbits decay from the radius where alpha similar to 1 to the halo centre with no local tidal mass transfer, and thus causes a rapid steepening of the inner profile to alpha > 1. These tidal effects, the resultant steepening of the profile to a cusp, and the stability of this cusp to tandem mergers with compact satellites are demonstrated using N-body simulations. The transition at alpha similar to 1 is then addressed using toy models in the limiting cases of impulse and adiabatic approximations and using tidal radii for satellites on radial and circular orbits. In an associated paper, we address the subsequent slow convergence from either side to an asymptotic stable cusp with alpha greater than or similar to 1. Our analysis thus implies that an inner cusp is enforced when small haloes are typically more compact than larger haloes, as in the CDM scenario, such that enough satellite material makes it intact into the inner halo and is deposited there. We conclude that a necessary condition for maintaining a flat core, as indicated by observations, is that the inner regions of the CDM satellite haloes be puffed up by about 50 per cent such that when they merge into a larger halo they would be disrupted outside the halo core. This puffing up could be due to baryonic feedback processes in small haloes, which may be stimulated by the tidal compression in the halo cores.

We propose a model for how the buildup of dark halos by merging satellites produces a characteristic inner cusp, with a density profile ρ ∝ r, where αin → αas ≳ 1, as seen in cosmological N-body simulations of hierarchical clustering scenarios. Dekel, Devor, & Hetzroni argue that a flat core of αin < 1 exerts tidal compression that prevents local deposit of satellite material; the satellite sinks intact into the halo center, thus causing a rapid steepening to αin > 1. Using merger N-body simulations, we learn that this cusp is stable under a sequence of mergers and derive a practical tidal mass transfer recipe in regions where the local slope of the halo profile is α > 1. According to this recipe, the ratio of mean densities of the halo and initial satellite within the tidal radius equals a given function ψ(α), which is significantly smaller than unity (compared to being ~1 according to crude resonance criteria) and is a decreasing function of α. This decrease makes the tidal mass transfer relatively more efficient at larger α, which means steepening when α is small and flattening when α is large, thus causing convergence to a stable solution. Given this mass transfer recipe, linear perturbation analysis, supported by toy simulations, shows that a sequence of cosmological mergers with homologous satellites slowly leads to a fixed-point cusp with an asymptotic slope αas > 1. The slope depends only weakly on the fluctuation power spectrum, in agreement with cosmological simulations. During a long interim period the profile has an NFW-like shape, with a cusp of 1 < αin < αas. Thus, a cusp is enforced if enough compact satellite remnants make it intact into the inner halo. In order to maintain a flat core, satellites must be disrupted outside the core, possibly as a result of a modest puffing up due to baryonic feedback.

We show how the buildup of halos by merging satellites forces an inner cusp, with a density profile \rho \propto r^{-\alpha} where \alpha \to \alpha_a \gsim 1$. Our analysis is based on a new prescription for tidal stripping as a function of \alpha(r), using a simple toy model which matches N-body simulations. In a core of \alpha 1. Where \alpha > 1, the stripping of each satellite shell is preceded by gradual puffing up, which makes the stripping more efficient at larger \alpha, causing flattening where \alpha is large enough. Therefore, we can show using linear perturbation analysis that a sequence of mergers slowly leads to a fixed point \alpha(r)=\alpha_a. This result implies that a cusp is enforced as long as enough satellite material makes it into the inner halo and is deposited there. We conclude that in order to maintain a flat core, as indicated by observations, satellites must be disrupted outside the core, e.g., because of puffing up due to baryonic feedback effects.

We explain in simple terms how the buildup of dark halos by merging satellites inevitably leads to an inner cusp of density profile ρ ∝ r with α > ∼ 1, as seen in cosmological N-body simulations. A flatter core with α < 1 exerts on each satellite tidal compression in all directions, which prevents deposit of stripped satellite material in this region. This makes the satellite orbits decay from the radius where α ∼ 1 to the halo center with no tidal mass transfer in the core and thus causes a rapid steepening of the inner profile. The transition at α ∼ 1 is addressed qualitatively in the extreme limits of impulse and adiabatic approximations and using tidal radii for satellites on radial and circular orbits. These tidal effects and the resulting steepening of the profile are then demonstrated using merger N-body simulations. In an associated paper we address the subsequent slow convergence to an asymptotic stable cusp with α > ∼ 1. Our result implies that an inner cusp is enforced as long as enough satellite material makes it intact into the inner halo and is deposited there. We conclude that in order to maintain a flat core as indicated by observations, CDM satellites must be disrupted outside the core. This could be the result of puffing up of small halos due to baryonic feedback processes, which could actually be stimulated by the same effect of tidal compression in the halo core.

We propose a model for how the buildup of dark halos by merging satellites produces an inner cusp, of a density profile ρ ∝ rin with αin → αas > ∼ 1, as seen in cosmological N-body simulations. Dekel & Devor (2002) showed that a core of αin < 1 exerts tidal compression which prevents local deposit of satellite material; the satellite sinks intact into the halo center which causes steepening to αin > 1. Using merger simulations we derive here a mass-transfer recipe in regions where the local slope is α > 1, according to which the ratio of mean densities of halo and initial satellite within the tidal radius equals a given function ψ(α) that is decreasing with α. This makes the mass transfer relatively more efficient at larger α, which causes steepening of the profile at small α and flattening at large α. Given this mass-transfer recipe, linear perturbation analysis, supported by toy simulations, shows that a sequence of cosmological mergers with homologous satellites slowly leads to a fixed-point asymptotic cusp with a slope αas > 1. The cusp depends only weakly on the power spectrum of fluctuations, in agreement with cosmological N-body simulations. During a long interim period the profile has an NFW-like shape, with a cusp of 1 < αin < αas. Thus, a cusp is enforced if enough satellite remnants make it intact into the inner halo. In order to maintain a flat core, satellites must be disrupted outside the core, e.g., as a result of puffing up due to baryonic feedback.