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We study a combined sample of 264 star-forming, 51 composite, and 73 active galaxies using optical spectra from SDSS and mid-infrared (mid-IR) spectra from the Spitzer Infrared Spectrograph. We examine optical and mid-IR spectroscopic…

In order to analyse the large numbers of Seyfert galaxy spectra available at present, we are testing new techniques to derive their physical parameters fastly and accurately. We present an experiment on such a new technique to segregate old…

The classification of galaxies as spirals or ellipticals is a crucial task in understanding their formation and evolution. With the arrival of large-scale astronomical surveys, such as the Sloan Digital Sky Survey (SDSS), astronomers now…

Context. Active galactic nuclei (AGNs) and star forming galaxies (SFGs) are the primary sources of extragalactic radio sky. But it is difficult to distinguish the radio emission produced by AGNs from that by SFGs, especially when the radio…

Different activation functions work best for different deep learning models. To exploit this, we leverage recent advancements in gradient-based search techniques for neural architectures to efficiently identify high-performing activation…

In order to develop systems capable of artificial evolution, we need to identify which systems can produce complex behavior. We present a novel classification method applicable to any class of deterministic discrete space and time dynamical…

The characterization of the dynamical state of galaxies up to z~7 is crucial for constraining the mechanisms driving the mass assembly in the early Universe. However, it is unclear whether the data quality of current and future observations…

In order to perform a more complete census of active galactic nuclei (AGN) in the local Universe, we investigate the use of the HeII~$\lambda 4685$ emission line diagnostic diagram by Shirazi & Brinchmann (2012) in addition to the standard…

Targeted searches for dual active galactic nuclei (AGN), with separations 1 -- 10 kpc, have yielded relatively few successes. A recent pilot survey by Satyapal et al. has demonstrated that mid-infrared (mid-IR) pre-selection has the…

We investigate the link between AGN activity, star-formation and stellar mass of the host galaxy at 0<z<1, looking for spectroscopic traces of AGN and aging of the host. This work provides an extension of the existing studies at z<0.1 and…

We report on a new method to identify Active Galactic Nuclei (AGN) among unidentified INTEGRAL sources. This method consists of cross-correlating unidentified sources listed in the fourth IBIS Survey Catalogue first with infrared and then…

Supermassive black holes (SMBHs) have been detected in the centers of most nearby massive galaxies. Galaxies today are the products of billions of years of galaxy mergers, but also billions of years of SMBH activity as active galactic…

We present a new implementation of the GAlaxy Evolution and Assembly (GAEA) semi-analytic model, that features an improved modelling of the process of cold gas accretion onto supermassive black hole (SMBHs), derived from both analytic…

We study sensor-based human activity recognition in manual work processes like assembly tasks. In such processes, the system states often have a rich structure, involving object properties and relations. Thus, estimating the hidden system…

We present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the…

We address the problem of morphological classification of galaxies from the Galaxy Zoo DECaLS dataset using classical machine learning techniques. Our approach employs a dimensionality reduction method followed by a classical classifier to…

Active galactic nuclei (AGN) are typically identified through their distinctive X-ray or radio emissions, mid-infrared (MIR) colors, or emission lines. However, each method captures different subsets of AGN due to signal-to-noise (SNR)…

To explain the properties of the local galaxy population, theoretical models require active galactic nuclei (AGN) to inject energy into host galaxies, thereby expelling outflows of gas that would otherwise form stars. Observational tests of…

Data generation is a data augmentation technique for enhancing the generalization ability for skeleton-based human action recognition. Most existing data generation methods face challenges to ensure the temporal consistency of the dynamic…

Using the 'k-means' cluster analysis algorithm, we carry out an unsupervised classification of all galaxy spectra in the seventh and final Sloan Digital Sky Survey data release (SDSS/DR7). Except for the shift to restframe wavelengths, and…