Search results for "shift"

Euclid preparation : XXII. Selection of quiescent galaxies from mock photometry using machine learning

2023

The Euclid Space Telescope will provide deep imaging at optical and near-infrared wavelengths, along with slitless near-infrared spectroscopy, across ~15 000deg2 of the sky. Euclid is expected to detect ~12 billion astronomical sources, facilitating new insights into cosmology, galaxy evolution, and various other topics. In order to optimally exploit the expected very large dataset, appropriate methods and software tools need to be developed. Here we present a novel machine-learning-based methodology for the selection of quiescent galaxies using broadband Euclid IE, YE, JE, and HE photometry, in combination with multi-wavelength photometry from other large surveys (e.g. the Rubin LSST). The…

Euclid preparation : XXI. Intermediate-redshift contaminants in the search for z > 6 galaxies within the Euclid Deep Survey

2022

Mass-Metallicity Relation from Cosmological Hydrodynamical Simulations and X-ray Observations of Galaxy Groups and Clusters

2018

Recent X-ray observations of galaxy clusters show that the distribution of intra-cluster medium (ICM) metallicity is remarkably uniform in space and time. In this paper, we analyse a large sample of simulated objects, from poor groups to rich clusters, to study the dependence of the metallicity and related quantities on the mass of the systems. The simulations are performed with an improved version of the Smoothed-Particle-Hydrodynamics \texttt{GADGET-3} code and consider various astrophysical processes including radiative cooling, metal enrichment and feedback from stars and active galactic nuclei (AGN). The scaling between the metallicity and the temperature obtained in the simulations ag…

Cosmological hydrodynamical simulations of galaxy clusters: X-ray scaling relations and their evolution

2018

We analyse cosmological hydrodynamical simulations of galaxy clusters to study the X-ray scaling relations between total masses and observable quantities such as X-ray luminosity, gas mass, X-ray temperature, and $Y_{X}$. Three sets of simulations are performed with an improved version of the smoothed particle hydrodynamics GADGET-3 code. These consider the following: non-radiative gas, star formation and stellar feedback, and the addition of feedback by active galactic nuclei (AGN). We select clusters with $M_{500} > 10^{14} M_{\odot} E(z)^{-1}$, mimicking the typical selection of Sunyaev-Zeldovich samples. This permits to have a mass range large enough to enable robust fitting of the r…

Searching for differences in Swift's intermediate GRBs

2010

Gamma-ray bursts are usually classified through their high-energy emission into short-duration and long-duration bursts, which presumably reflect two different types of progenitors. However, it has been shown on statistical grounds that a third, intermediate population is needed in this classification scheme, although an extensive study of the properties of this class has so far not been done. The large amount of follow-up studies generated during the Swift era allows us to have a suficient sample to attempt a study of this third population through the properties of their prompt emission and their afterglows. Our study is focused on a sample of GRBs observed by Swift during its first four y…

Faint γ-ray sources at low redshift: the radio galaxy IC 1531

2018

We present amultiwavelength study of IC 1531 (z=0.02564), an extragalactic radio source associated with the γ -ray object 3FGL J0009.9-3206 and classified as a blazar of uncertain type in the Third Fermi-Large Area Telescope AGN catalog (3LAC). A core-jet structure, visible in radio and X-rays, is enclosed within a ~220 kpc wide radio structure. The morphology and spectral characteristics of the kiloparsec jet in radio and X-rays are typical of Fanaroff-Riley type I galaxies. The analysis of the radio data and optical spectrum and different diagnostic methods based on the optical, infrared, and γ -ray luminosities also support a classification as a low-power RG seen at moderate angles (θ = …

Iodine(I) and Silver(I) Complexes of Benzoimidazole and Pyridylcarbazole Derivatives

2021

The synthesis of iodine(I) complexes with either benzoimidazole or carbazole-derived sp 2 N -containing Lewis bases is described, as well as their corresponding silver(I) complexes. The addition of elemental iodine to the linear two-coordinate Ag(I) complexes produces iodine(I) complexes with a three-center four-electron (3c-4e) [N — I — N] + bond. The 1 H and 1 H- 15 N HMBC NMR studies unambiguously confirm the formation of the complexes in all cases via the [N — Ag — N] + → [N — I — N] + cation exchange, with the 15 N NMR chemical shift change between 94 to 111 ppm when compared to the free ligand. The single crystal X-ray crystallographic studies on four I + complexes revealed highly sym…

Analysis of Electrical Loads and Strategies for Increasing Self-Consumption with BIPV Case study : Skarpnes Zero-Energy House

2017

Master's thesis Renewable Energy ENE500 - University of Agder 2017 At Skarpnes village (Southern Norway), the houses as zero energy buildings (ZEB) are installed with Building Integrated Photovoltaic (BIPV) systems, and these houses are not containing smart control of equipments. The aim of such buildings is that the amount of electrical energy produced is the same as that consumed in the buildings on an annual basis. In this thesis, the main objective is to analyse the methods for increasing self -consumption in BIPV, by minimizing the cost of purchasing electricity from the grid at time with no PV production, and maximizing the utilization of solar PV generated power, which reduces the po…

Unraveling the prominent role of the Rh/ZrO2-interface in the water-gas shift reaction via a first principles microkinetic study

2018

The industrially important water–gas-shift (WGS) reaction is a complex network of competing elementary reactions in which the catalyst is a multicomponent system consisting of distinct domains. Herein, we have combined density functional theory calculations with microkinetic modeling to explore the active phase, kinetics, and reaction mechanism of the WGS over the Rh–ZrO2 interface. We have explicitly considered the support and metal and their interface and find that the Rh–ZrO2 interface is far more active toward WGS than Rh(111) facets, which are susceptible to CO poisoning. CO2 forming on the zirconia support rapidly transforms into formate. These findings demonstrate the central role of…

The ALHAMBRA survey: Discovery of a faint QSO at z = 5.41 (Research Note)

2013

Aims. We aim to illustrate the potentiality of the Advanced Large, Homogeneous Area, Medium-Band Redshift Astronomical (ALHAMBRA) survey to investigate the high-redshift universe through the detection of quasi stellar objects (QSOs) at redshifts higher than 5. Methods. We searched for QSOs candidates at high redshift by fitting an extensive library of spectral energy distributions – including active and non-active galaxy templates, as well as stars – to the photometric database of the ALHAMBRA survey (composed of 20 optical medium-band plus the 3 broad-band JHKs near-infrared filters). Results. Our selection over ≈1 square degree of ALHAMBRA data (∼1/4 of the total area covered by the surve…