High resolution near-infrared imaging of submillimeter galaxies

We present F110W (~J) and F160W (~H) observations of ten submillimeter galaxies (SMGs) obtained with the Hubble Space Telescope's (HST's) NICMOS camera. Our targets have optical redshifts in the range 2.20<z<2.81 confirmed by millimeter CO or mid-IR spectroscopy, guaranteeing that the two bands sample the rest-frame optical with the Balmer break falling between them. Eight of ten are detected in both bands, while two are detected in F160W only. We study their F160W morphologies, applying a maximum-deblending detection algorithm to distinguish multiple- from single-component configurations, leading to reassessments for several objects. Based on our NICMOS imaging and/or previous dynamical evidence we identify five SMGs as multiple sources, which we interpret as merging systems. Additionally, we calculate morphological parameters asymmetry (A) and Gini coefficient (G); thanks to our sample's limited redshift range we recover the trend that multiple-component, merger-like morphologies are reflected in higher asymmetries. We analyze the stellar populations of nine objects with F110W/F160W photometry, using archival HST optical data when available. For multiple systems, we are able to model the individual components that build up an SMG. With the available data we cannot discriminate among star formation histories, but we constrain stellar masses and mass ratios for merger-like SMG systems, obtaining a mean log(M_*/M_sun)=10.9+/-0.2 for our full sample, with individual values log(M_*/M_sun)~9.6-11.8. The morphologies and mass ratios of the least and most massive systems match the predictions of the major-merger and cold accretion SMG formation scenarios, respectively, suggesting that both channels may have a role in the population's origin.Comment: 41 pages preprint, 3 figures, published in ApJ on 2013 May 1

THE ALIGNMENT BETWEEN SYSTEM AND OPERATIONAL EFFECTIVENESS: A CASE STUDY IN THE ELECTRICAL SECTOR IN AUSTRALIA.

Organizations are increasingly investing in complex enterprise information systems.  In most cases, claims are made concerning how these expensive systems will produce considerable improvements in the operational performance of the organizations.  Nevertheless, there is evidence that many of these systems fail to deliver the expected outcomes and often fail completely.  This study explores the linkages among system effectiveness, operational performance, and the organizational factors that influence the balance that these systems require. As current literature is silent in regard to such interactions, this research uses a qualitative approach, based on unstructured interviews with employees at different levels in an electricity distribution enterprise, to build on the existing literature and to further confirm and refine a theoretical framework

Ge/Si as a tracer for Si in paired catchments of the Luquillo CZO

Catchment lithology is a significant factor influencing the generation and transport of solutes in the critical zone. In the Luquillo Mountains of Puerto Rico, the Quebrada Guaba and Bisley catchments are studied to understand how lithology affects concentration-discharge (C-Q) relationships. Ge/Si ratios in pore water and stream samples are used to identify sources of Si to streams in the Bisley 1 watershed. Quebrada Guaba is underlain by quartz diorite and is characterized by strong Si dilution behavior (power law slope = -0.47)^1. During baseflow, Ge/Si = 0.27-0.47 μmol mol^-1 due to weathering of plagioclase and precipitation of Ge enriched kaolinite in the bedrock-saprolite interface2. During storms, hydrologic pathways shift to shallower flow paths with lower Si concentrations and higher Ge/Si (1.0-4.0 μmol mol^-1)^3. The shift to saprolite-dominated flow paths carrying dilute Si end-members drives the Si-Q pattern in this catchment. The volcaniclastic sub-catchment of Bisley 1 has a more chemostatic Si-Q relationship (power law slope of = -0.30)^1. In this study, lysemeters at the Bisley sites of B1S1, B1S2 and B1R show higher Si pore water concentrations than the LG sites at Quebrada Guaba. Ge/Si ratios for Bisley are lower than Guaba except for 200-300 cm depth were ratios increase to 2.87 μmol mol^-1 (B1S1). Dissolved Si concentrations increase markedly from 200 cm to the surface at B1S1 and B1S2. Ge/Si shows the opposite trend with ratios decreasing from 2.87 to 0.86 μmol mol^-1. This pattern of increased pore water Si and low Ge/Si may be due to phytolith dissolution also observed in Quebrada Guaba^2,4. Bisleys greater Si depletion near the surface may result in more sensitivity to phytolith inputs. Stream samples from Bisley 1 will be analyzed for major cations and Ge/Si to understand how pore water or other shallow surface reservoirs influence Si-Q patterns in this catchment.https://whiteiron.org/uploads/conferences/28/program/programVolume.pdfPublished versio

Ages for exoplanet host stars

Age is an important characteristic of a planetary system, but also one that is difficult to determine. Assuming that the host star and the planets are formed at the same time, the challenge is to determine the stellar age. Asteroseismology provides precise age determination, but in many cases the required detailed pulsation observations are not available. Here we concentrate on other techniques, which may have broader applicability but also serious limitations. Further development of this area requires improvements in our understanding of the evolution of stars and their age-dependent characteristics, combined with observations that allow reliable calibration of the various techniques.Comment: To appear in "Handbook of Exoplanets", eds. Deeg, H.J. & Belmonte, J.A, Springer (2018

A velocity decomposition method for exergy-based drag prediction

The exergy method is a powerful tool for aerodynamic analysis and drag prediction. However, its formulation still requires further improvements in order to obtain a useful drag breakdown for the analysis of wind tunnel data (like the far-field methods). The far-field drag breakdown is achieved by using a velocity decomposition technique but the related formulation is not well suited for the exergy method. Thus, the main objective of this work is to develop a new velocity decomposition suited for the exergy analysis and to propose a related exergy-based drag breakdown formulation for wind tunnel applications

K2-97b: A (Re-?)Inflated Planet Orbiting a Red Giant Star

Strongly irradiated giant planets are observed to have radii larger than thermal evolution models predict. Although these inflated planets have been known for over 15 years, it is unclear whether their inflation is caused by the deposition of energy from the host star or the inhibited cooling of the planet. These processes can be distinguished if the planet becomes highly irradiated only when the host star evolves onto the red giant branch. We report the discovery of K2-97b, a 1.31 ± 0.11 R_J, 1.10 ± 0.11 M_J planet orbiting a 4.20 ± 0.14 R⊙, 1.16 ± 0.12 M⊙ red giant star with an orbital period of 8.4 days. We precisely constrained stellar and planetary parameters by combining asteroseismology, spectroscopy, and granulation noise modeling along with transit and radial velocity measurements. The uncertainty in planet radius is dominated by systematic differences in transit depth, which we measure to be up to 30% between different light-curve reduction methods. Our calculations indicate the incident flux on this planet was 170^(+140)_(-60) times the incident flux on Earth, while the star was on the main sequence. Previous studies suggest that this incident flux is insufficient to delay planetary cooling enough to explain the present planet radius. This system thus provides the first evidence that planets may be inflated directly by incident stellar radiation rather than by delayed loss of heat from formation. Further studies of planets around red giant branch stars will confirm or contradict this hypothesis and may reveal a new class of re-inflated planets

THE K2 M67 STUDY: REVISITING OLD FRIENDS WITH K2 REVEALS OSCILLATING RED GIANTS IN THE OPEN CLUSTER M67

Observations of stellar clusters have had a tremendous impact in forming our understanding of stellar evolution. The open cluster M67 has a particularly important role as a calibration benchmark for stellar evolution theory due to its near-solar composition and age. As a result, it has been observed extensively, including attempts to detect solar-like oscillations in its main sequence and red giant stars. However, any asteroseismic inference has so far remained elusive due to the difficulty in measuring these extremely low-amplitude oscillations. Here we report the first unambiguous detection of solar-like oscillations in the red giants of M67. We use data from the Kepler ecliptic mission, K2, to measure the global asteroseismic properties. We find a model-independent seismic-informed distance of 816 ±11 pc, or (m - M)0 = 9.57 ± 0.03 mag, an average red giant mass of 1.36 ± 0.01 M⊙, in agreement with the dynamical mass from an eclipsing binary near the cluster turn-off, and ages of individual stars compatible with isochrone fitting. We see no evidence of strong mass loss on the red giant branch. We also determine seismic of all the cluster giants with a typical precision of ∼0.01 dex. Our results generally show good agreement with independent methods and support the use of seismic scaling relations to determine global properties of red giant stars with near-solar metallicity. We further illustrate that the data are of such high quality that future work on individual mode frequencies should be possible, which would extend the scope of seismic analysis of this cluster

Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run

We present revised properties for 196,468 stars observed by the NASA Kepler Mission and used in the analysis of Quarter 1-16 (Q1-Q16) data to detect and characterize transiting exoplanets. The catalog is based on a compilation of literature values for atmospheric properties (temperature, surface gravity, and metallicity) derived from different observational techniques (photometry, spectroscopy, asteroseismology, and exoplanet transits), which were then homogeneously fitted to a grid of Dartmouth stellar isochrones. We use broadband photometry and asteroseismology to characterize 11,532 Kepler targets which were previously unclassified in the Kepler Input Catalog (KIC). We report the detection of oscillations in 2,762 of these targets, classifying them as giant stars and increasing the number of known oscillating giant stars observed by Kepler by ~20% to a total of ~15,500 stars. Typical uncertainties in derived radii and masses are ~40% and ~20%, respectively, for stars with photometric constraints only, and 5-15% and ~10% for stars based on spectroscopy and/or asteroseismology, although these uncertainties vary strongly with spectral type and luminosity class. A comparison with the Q1-Q12 catalog shows a systematic decrease in radii for M dwarfs, while radii for K dwarfs decrease or increase depending on the Q1-Q12 provenance (KIC or Yonsei-Yale isochrones). Radii of F-G dwarfs are on average unchanged, with the exception of newly identified giants. The Q1-Q16 star properties catalog is a first step towards an improved characterization of all Kepler targets to support planet occurrence studies.Comment: 20 pages, 14 figures, 5 tables; accepted for publication in ApJS; electronic versions of Tables 4 and 5 are available as ancillary files (see sidebar on the right), and an interactive version of Table 5 is available at the NASA Exoplanet Archive (http://exoplanetarchive.ipac.caltech.edu/