- Cosmological simulations of galaxy formation: Successes and challenges in the era of supercomputers. Ludwig Biermann Award Lecture 2012
- Scannapieco, C.
I use cosmological hydrodynamical simulations to study the formation and evolution of galaxies similar in mass to the Milky Way. First, I use a set of eight simulations where the haloes have a great variety of merger and formation histories, to inve …
- Betti Numbers of Gaussian Fields
- Park, Changbom; Pranav, Pratyush; Chingangbam, Pravabati; van de Weygaert, Rien; Jones, Bernard; Vegter, Gert; Kim, Inkang; Hidding, Johan; Hellwing, Wojciech A.
We present the relation between the genus in cosmology and the Betti numbers for excursion sets of three- and two-dimensional smooth Gaussian random fields, and numerically investigate the Betti numbers as a function of threshold level. Betti number …
- Coronal loop physical parameters from the analysis of multiple observed transverse oscillations
- Asensio Ramos, A.; Arregui, I.
The analysis of quickly damped transverse oscillations of solar coronal loops using magneto-hydrodynamic seismology allows us to infer physical parameters that are difficult to measure otherwise. Under the assumption that such damped oscillations ar …
- Assessment of stochastic and deterministic models of 6304 quasar lightcurves from SDSS Stripe 82
- Andrae, R.; Kim, D.-W.; Bailer-Jones, C. A. L.
The optical lightcurves of many quasars show variations of tenths of a magnitude or more on timescales of months to years. This variation often cannot be described well by a simple deterministic model. We perform a Bayesian comparison of over 20 det …
- Period Error Estimation for the Kepler Eclipsing Binary Catalog
- Mighell, Kenneth J.; Plavchan, Peter
The Kepler Eclipsing Binary Catalog (KEBC) describes 2165 eclipsing binaries identified in the 115 deg2 Kepler Field based on observations from Kepler quarters Q0, Q1, and Q2. The periods in the KEBC are given in units of days out to six decimal pla …
- Estimating the Properties of Hard X-Ray Solar Flares by Constraining Model Parameters
- Ireland, J.; Tolbert, A. K.; Schwartz, R. A.; Holman, G. D.; Dennis, B. R.
We wish to better constrain the properties of solar flares by exploring how parameterized models of solar flares interact with uncertainty estimation methods. We compare four different methods of calculating uncertainty estimates in fitting paramete …
- A New Result on the Origin of the Extragalactic Gamma-Ray Background
- Zhou, Ming; Wang, Jiancheng
In this paper, we repeatedly use the method of image stacking to study the origin of the extragalactic gamma-ray background (EGB) at GeV bands, and find that the Faint Images of the Radio Sky at Twenty centimeters (FIRST) sources undetected by the L …
- Candidate Planets in the Habitable Zones of Kepler Stars
- Gaidos, Eric
A key goal of the Kepler mission is the discovery of Earth-size transiting planets in “habitable zones” where stellar irradiance maintains a temperate climate on an Earth-like planet. Robust estimates of planet radius and irradiance require accurate …
- Maximum Likelihood Analysis of Systematic Errors in Interferometric Observations of the Cosmic Microwave Background
- Zhang, Le; Karakci, Ata; Sutter, Paul M.; Bunn, Emory F.; Korotkov, Andrei; Timbie, Peter; Tucker, Gregory S.; Wandelt, Benjamin D.
We investigate the impact of instrumental systematic errors in interferometric measurements of the cosmic microwave background (CMB) temperature and polarization power spectra. We simulate interferometric CMB observations to generate mock visibiliti …
- χ2 Discriminators for Transiting Planet Detection in Kepler Data
- Seader, Shawn; Tenenbaum, Peter; Jenkins, Jon M.; Burke, Christopher J.
The Kepler spacecraft observes a host of target stars to detect transiting planets. Requiring a 7.1σ detection in three years of data yields over 100,000 detections, many of which are false alarms. After a second cut is made on a robust detection s …
- Recovering redshift distributions with cross-correlations: pushing the boundaries
- Schmidt, Samuel J.; Ménard, Brice; Scranton, Ryan; Morrison, Christopher; McBride, Cameron K.
Determining accurate redshift distributions for very large samples of objects has become increasingly important in cosmology. We investigate the impact of extending cross-correlation based redshift distribution recovery methods to include small-scal …
- Minimum variability time-scales of long and short GRBs
- MacLachlan, G. A.; Shenoy, A.; Sonbas, E.; Dhuga, K. S.; Cobb, B. E.; Ukwatta, T. N.; Morris, D. C.; Eskandarian, A.; Maximon, L. C.; Parke, W. C.
We have investigated the time variations in the light curves from a sample of long and short Fermi/GBM gamma-ray bursts (GRBs) using an impartial wavelet analysis. The results indicate that in the source frame, the variability time-scales for long b …
- Order statistics applied to the most massive and most distant galaxy clusters
- Waizmann, J.-C.; Ettori, S.; Bartelmann, M.
In this work, we present an analytic framework for calculating the individual and joint distributions of the nth most massive or nth highest redshift galaxy cluster for a given survey characteristic allowing us to formulate Λ cold dark matter (ΛCD …
- TPZ: photometric redshift PDFs and ancillary information by using prediction trees and random forests
- Carrasco Kind, Matias; Brunner, Robert J.
With the growth of large photometric surveys, accurately estimating photometric redshifts, preferably as a probability density function (PDF), and fully understanding the implicit systematic uncertainties in this process, has become increasingly imp …
- Universal Scaling Law in Long Gamma-Ray Bursts
- Tsutsui, Ryo; Shigeyama, Toshikazu
The overwhelming diversity of long gamma-ray bursts (LGRBs), discovered after the launch of the Swift satellite,is a major obstacle to LGRB studies. Recently, it was shown that the prompt emission of LGRBs can be classified into three subclasses: Ty …
- NIFTY – Numerical Information Field Theory. A versatile PYTHON library for signal inference
- Selig, M.; Bell, M. R.; Junklewitz, H.; Oppermann, N.; Reinecke, M.; Greiner, M.; Pachajoa, C.; Enßlin, T. A.
NIFTy (Numerical Information Field Theory) is a software package designed to enable the development of signal inference algorithms that operate regardless of the underlying spatial grid and its resolution. Its object-oriented framework is written in …
- Reconstructing the Shape of the Correlation Function
- Huffenberger, K. M.; Galeazzi, M.; Ursino, E.
We develop an estimator for the correlation function which, in the ensemble average, returns the shape of the correlation function, even for signals that have significant correlations on the scale of the survey region. Our estimator is general and w …
- Bayesian physical reconstruction of initial conditions from large-scale structure surveys
- Jasche, Jens; Wandelt, Benjamin D.
We present a fully probabilistic, physical model of the non-linearly evolved density field, as probed by realistic galaxy surveys. Our model is valid in the linear and mildly non-linear regimes and uses second-order Lagrangian perturbation theory to …
- How to Find More Supernovae with Less Work: Object Classification Techniques for Difference Imaging
- Bailey, S.; Aragon, C.; Romano, R.; Thomas, R. C.; Weaver, B. A.; Wong, D.
We present the results of applying new object classification techniques to difference images in the context of the Nearby Supernova Factory supernova search. Most current supernova searches subtract reference images from new images, identify objects …
- Measuring X-ray variability in faint/sparsely-sampled AGN
- Allevato, V.; Paolillo, M.; Papadakis, I.; Pinto, C.
We study the statistical properties of the Normalized Excess Variance of variability process characterized by a red-noise power spectral density (PSD), as the case of Active Galactic Nuclei (AGN). We perform Monte Carlo simulations of lightcurves, a …