Manolis Plionis

Manolis Plionis
Aristotle University of Thessaloniki | AUTH · School of Physics

PhD Univ. of Sussex, 1989

About

269
Publications
12,643
Reads
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4,144
Citations
Additional affiliations
January 2017 - present
National Observatory of Athens
Position
  • Managing Director
Description
  • Director of Center and President of the BoD
October 2012 - present
Aristotle University of Thessaloniki
Position
  • Professor (Full)
June 2011 - June 2011
Universitat de Barcelona
Position
  • Visiting scientist
Education
October 1984 - July 1989
University of Sussex
Field of study
  • Astrophysics
September 1983 - September 1984
University of Sussex
Field of study
  • Astronomy
September 1978 - July 1983
University of Crete
Field of study
  • Mathematics

Publications

Publications (269)
Article
Full-text available
We present a three-dimensional study of the local (<100 h^-1} kpc) and the large scale (<1 h^{-1} Mpc) environment of the two main types of Seyfert AGN galaxies. For this purpose we use 48 Sy1 galaxies (with redshifts in the range 0.007<z<0.036) and 56 Sy2 galaxies (with 0.004<z<0.020), located at high galactic latitudes, as well as two control sam...
Article
Full-text available
In the hierarchical structure formation model cosmic halos are supposed to form by accretion of smaller units along anisotropic direction, defined by large-scale filamentary structures. After the epoch of primary mass aggregation (which depend on the cosmological model), violent relaxation processes will tend to alter the halo phase-space configura...
Article
Full-text available
We study the global dynamics of the universe within the framework of the Interacting Dark Matter (IDM) scenario. Assuming that the dark matter obeys the collisional Boltzmann equation, we can derive analytical solutions of the global density evolution, which can accommodate an accelerated expansion, equivalent to either the {\em quintessence} or th...
Article
Full-text available
We estimate the distribution of intrinsic shapes of the APM galaxy clusters from their corresponding distribution of projected shapes. We smooth the discrete galaxy distribution and define the cluster shape by fitting the best ellipse to the different isodensity contours. Using Monte-Carlo simulations we have studied the performance of our method i...
Preprint
Full-text available
We study the host galaxy properties of active galactic nuclei (AGN) that have been detected in X-rays in the nearby Universe ($\rm z<0.2$). For that purpose, we use the catalogue provided by the ROSAT-2RXS in the 0.1-2.4\,keV energy band, one of the largest X-ray datasets with spectroscopic observations. Our sample consists of $\sim 900$ X-ray AGN....
Article
We place novel constraints on the cosmokinetic parameters by using a joint analysis of the newest VLT-KMOS HII galaxies (HIIG) with the Supernovae Type Ia (SNIa) Pantheon sample. We combine the latter data sets in order to reconstruct, in a model independent way, the Hubble diagram to as high redshifts as possible. Using a Gaussian process we deriv...
Preprint
Full-text available
We present the forward cosmological analysis of an $XMM$ selected sample of galaxy clusters out to a redshift of unity. Following our previous 2018 study based on the dn/dz quantity alone, we perform an upgraded cosmological analysis of the same XXL C1 cluster catalogue (178 objects), with a detailed account of the systematic errors. We follow the...
Article
We present novel cosmological constraints based on a joint analysis of our HII galaxies (HIIG) Hubble relation with the full Planck Cosmic Microwave Background anisotropy spectrum and the Baryon Acoustic Oscillations (BAO) probes. The HII galaxies span a large redshift range (0.088 ≤ z ≤ 2.5), reaching significantly higher redshifts than available...
Preprint
Full-text available
We place novel constraints on the cosmokinetic parameters by using a joint analysis of the newest VLT-KMOS HII galaxies (HIIG) with the Supernovae Type Ia (SNIa) Pantheon sample. We combine the latter datasets in order to reconstruct, in a model-independent way, the Hubble diagram to as high redshifts as possible. Using a Gaussian process we derive...
Preprint
Full-text available
We present novel cosmological constraints based on a joint analysis of our HII galaxies (HIIG) Hubble relation with the full Planck Cosmic Microwave Background anisotropy spectrum and the Baryon Acoustic Oscillations (BAO) probes. The HII galaxies span a large redshift range $(0.088 \le z \le 2.5)$, reaching significantly higher redshifts than avai...
Preprint
Full-text available
We studied a sample of 274 radio and X-ray selected quasars (XQSOs) detected in the COSMOS and XXL-S radio surveys at 3 GHz and 2.1 GHz, respectively. This sample was identified by adopting a conservative threshold in X-ray luminosity, Lx [2-10\ keV] >= 10^44 erg/s, selecting only the most powerful quasars. Using available multiwavelength data, we...
Article
Aims. The main purpose of this study is to investigate aspects regarding the validity of the active galactic nucleus (AGN) unification paradigm (UP). In particular, we focus on the AGN host galaxies, which according to the UP should show no systematic differences depending on the AGN classification. Methods. For the purpose of this study, we used (...
Article
Full-text available
We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(Hβ), and the velocity dispersion (σ) for H ii galaxies (HIIG). These results are based on new VLT-KMOS high spectral resolution observations of 41 high-z (1.3 ≤ z ≤2.6) HIIG combine...
Preprint
Full-text available
We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(H$\beta$), and the velocity dispersion ($\sigma$) for HII galaxies (HIIG). These results are based on new VLT-KMOS high spectral resolution observations of 41 high-z ($1.3 \leq$ z $...
Article
Large samples of galaxy clusters provide knowledge of both astrophysics in the most massive virialised environments and the properties of the cosmological model that defines our Universe. However, an important issue that affects the interpretation of galaxy cluster samples is the role played by the selection waveband and the potential for this to i...
Preprint
Full-text available
Large samples of galaxy clusters provide knowledge of both astrophysics in the most massive virialised environments and the properties of the cosmological model that defines our Universe. However, an important issue that affects the interpretation of galaxy cluster samples is the role played by the selection waveband and the potential for this to i...
Article
Full-text available
Aims. In order to pinpoint the place of the (ultra-) luminous infrared galaxies ((U)LIRGs) in the local Universe, we examine the properties of a sample of 67 such nearby systems and compare them with those of 268 early- and 542 late-type, well studied, galaxies from the DustPedia database. Methods. We made use of multi-wavelength photometric data (...
Preprint
Full-text available
In order to pinpoint the place of the (U)LIRGs in the local Universe we examine the properties of a sample of 67 such systems and compare them with those of 268 ETGs and 542 LTGs from the DustPedia database. We make use of multi-wavelength photometric data and the CIGALE SED fitting code to extract their physical parameters. The median SEDs as well...
Article
Relatively few X-ray sources are known which have low mass galaxies as hosts. This is an important restriction on studies of Active Galactic Nuclei (AGN), hence black holes, and of X-ray binaries (XRBs) in low mass galaxies; addressing it requires very large samples of both galaxies and of X-ray sources. Here we have matched the X-ray point sources...
Article
Aims. We study the dependence of the dynamical properties of massive ( M ≥ 1.5 × 10 ¹³ M ⊙ h ⁻¹ ) dark matter halos on their environment in a whole-sky ΛCDM light-cone simulation extending to z ∼ 0.65. The properties of interest for this study are the halo shape (parametrized via its principal axes), spin and virialization status, the alignment of...
Preprint
Full-text available
The main purpose of this study is to investigate aspects regarding the validity of the AGN unification paradigm (UP). In particular we focus on the AGN host galaxies, which according to the UP should show no systematic differences depending on the AGN classification. For the purpose of this study we use (a) the spectroscopic SDSS (Sloan Digital Sky...
Article
Full-text available
We use 3,213 Active Galactic Nuclei (AGNs) from the XMM-XXL northern field to investigate the relation of AGN type with host galaxy properties. Applying a Bayesian method, we derive the hardness ratios (HRs) and through these the hydrogen column density (N H) for each source. We consider as absorbed sources (type-2) those with N H > 10 21.5 cm −2....
Preprint
Full-text available
We use 3,213 Active Galactic Nuclei (AGNs) from the $\it{XMM}$-XXL northern field to investigate the relation of AGN type with host galaxy properties. Applying a Bayesian method, we derive the hardness ratios (HRs) and through these the hydrogen column density ($\rm N_H$) for each source. We consider as absorbed sources (type-2) those with $\rm N_H...
Preprint
Full-text available
Aims: To study the dependence of the dynamical properties of dark matter halos on their environment in a whole-sky $\Lambda$CDM light-cone simulation extending to $z\sim 0.65$. The properties of interest are halo shape (parametrized by its principal axes), spin and virialisation status, the alignment of halo spin and shape, as well as the shape-sha...
Article
We studied a sample of 274 radio and X-ray selected quasars (XQSOs) detected in the COSMOS and XXL-S radio surveys at 3 GHz and 2.1 GHz, respectively. This sample was identified by adopting a conservative threshold in X-ray luminosity, L X [2−10 keV] ≥ 10 ⁴⁴ erg s ⁻¹ , selecting only the most powerful quasars. A number of previous studies on the or...
Article
Full-text available
We study the kinematics of the giant H ii regions NGC 5455 and NGC 5471 located in the galaxy M101, using integral field observations that include the H β and [O iii]$\, \lambda$ 5007 emission lines, obtained with the Keck Cosmic Web Imager. We analyse the line profiles using both single and multiple Gaussian curves, gathering evidence for the pres...
Preprint
Full-text available
We study the kinematics of the giant H II regions NGC 5455 and NGC 5471 located in the galaxy M101, using integral field observations that include the Hbeta and [O III] 5007 emission lines, obtained with the Keck Cosmic Web Imager. We analyse the line profiles using both single and multiple Gaussian curves, gathering evidence for the presence of se...
Article
We develop an optimization algorithm, using simulated annealing for the quantification of patterns in astronomical data based on techniques developed for robotic vision applications. The methodology falls in the category of cost minimization algorithms and it is based on user-determined interaction – among the pattern elements – criteria that defin...
Preprint
Full-text available
We develop an optimization algorithm, using simulated annealing (SA) for the quantification of patterns in astronomical data based on techniques developed for robotic vision applications. The methodology falls in the category of cost minimization algorithms and it is based on user-determined interaction - among the pattern elements - criteria which...
Article
Full-text available
We present new high spectral resolution observations of 15 high-z (1.3 ≤ z ≤2.5) H II galaxies (H II G) obtained with MOSFIRE at the Keck Observatory. These data, combined with already published data for another 31 high-z and 107 z ≤0.15 H II G, are used to obtain new independent cosmological results using the distance estimator based on the establ...
Preprint
Full-text available
We present new high spectral resolution observations of 15 high-z ($1.3 \leq$ z $\leq 2.5$) HII Galaxies (HIIG) obtained with MOSFIRE at the Keck Observatory. These data, combined with already published data for another 31 high-z and 107 z $\leq 0.15$ HIIG, are used to obtain new independent cosmological results using the distance estimator based o...
Article
Recent studies which select active galactic nucleus (AGN) in the mid-infrared (IR) part of the spectrum find that obscured AGNs reside in more massive dark matter haloes compared to unobscured ones. In contrast, X-ray AGN surveys do not find a difference in the dark matter haloes of these two populations.We visit anewthis issue by examining the clu...
Preprint
Full-text available
In the currently debated context of using clusters of galaxies as cosmological probes, the need for well-defined cluster samples is critical. The XXL Survey has been specifically designed to provide a well characterised sample of some 500 X-ray detected clusters suitable for cosmological studies. The main goal of present article is to make public a...
Article
Full-text available
Context. We present the results of a study of the active galactic nucleus (AGN) density in a homogeneous and well-studied sample of 167 bona fide X-ray galaxy clusters (0.1 < z < 0.5) from the XXL Survey, from the cluster core to the outskirts (up to 6 r 500 ). The results can provide evidence of the physical mechanisms that drive AGN and galaxy ev...
Article
Full-text available
Context. Galaxy clusters trace the highest density peaks in the large-scale structure of the Universe. Their clustering provides a powerful probe that can be exploited in combination with cluster mass measurements to strengthen the cosmological constraints provided by cluster number counts. Aims. We investigate the spatial properties of a homogeneo...
Preprint
Full-text available
Galaxy clusters trace the highest density peaks in the large-scale structure of the Universe. Their clustering provides a powerful probe that can be exploited in combination with cluster mass measurements to strengthen the cosmological constraints provided by cluster number counts. We investigate the spatial properties of a homogeneous sample of X-...
Conference Paper
Full-text available
The European space sciences landscape is very diverse as it involves two major intergovernmental organisations (The European Space Agency-ESA- and the European Commission-EC) and more than 25 countries that each have their national institutional setting and scientific planning approach. It has therefore always been essential to coordinate space sci...
Article
We present observations at 1.1 mm towards 16 powerful radio galaxies and a radio-quiet quasar at 0.5 < z < 6.3 acquired with the AzTEC camera mounted at the JCMT and ASTE to study the spatial distribution of submillimeter galaxies towards possible protocluster regions. The survey covers a total area of 1.01 square degrees with rms depths of 0.52 -...
Preprint
We present observations at 1.1 mm towards 16 powerful radio galaxies and a radio-quiet quasar at 0.5<z<6.3 acquired with the AzTEC camera mounted at the JCMT and ASTE to study the spatial distribution of submillimeter galaxies towards possible protocluster regions. The survey covers a total area of 1.01 square degrees with rms depths of 0.52 - 1.44...
Article
Full-text available
Aims . We study the dependence of the halo abundance function (AF) on different environments in a whole-sky ΛCDM light-cone halo catalogue extending to z ~ 0.65, using a simple and well-defined halo isolation criterion. Methods . The isolation status of each individual dark matter halo is determined by the distance to its nearest neighbour, which d...
Preprint
Full-text available
Aims.We study the dependence of the halo Abundance Function (AF) on different environments in a whole-sky {\Lambda}CDM light-cone halo catalogue extending to z~0.65, using a simple and well defined halo isolation criterion. Methods. The isolation status of each individual dark matter halo is determined by its nearest neighbour distance, which defin...
Preprint
Full-text available
Superclusters form from the largest enhancements in the primordial density perturbation field and extend for tens of Mpc, tracing the large-scale structure of the Universe. We characterise XLSSsCN01, a rich supercluster at z~0.3 detected in the XXL Survey, composed of X-ray clusters of different virial masses and luminosities. As one of the first s...
Article
Full-text available
The XMM-XXL Survey spans two fields of $\rm 25$ deg$^2$ each observed for more than 6Ms with XMM, which provided a sample of tens of thousands of point sources with a flux limit of $\sim 2.2 \times 10^{-15}$ and $\sim 1.4 \times 10^{-14}$ erg s$^{-1}$ cm$^{2}$, corresponding to 50% of the area curve, in the soft band and hard band, respectively. In...
Article
Full-text available
The classification of the host galaxies of the radio sources in the 25 deg$^2$ ultimate XMM extragalactic survey south field (XXL-S) is presented. XXL-S was surveyed at 2.1 GHz with the Australia Telescope Compact Array (ATCA) and is thus far the largest area radio survey conducted down to rms flux densities of $\sigma \sim 41$ $\mu$Jy beam$^{-1}$....
Article
Full-text available
A&A, in press Shortened abstract Full catalogues available online, see paper
Article
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Context. This work is part of a series of studies focusing on the environment and the properties of the X-ray selected active galactic nuclei (AGN) population from the XXL survey. The present survey, given its large area, continuity, extensive multiwavelength coverage, and large-scale structure information, is ideal for this kind of study. Here, we...
Article
Full-text available
Context. An X-ray survey with the XMM-Newton telescope, XMM-XXL, has identified hundreds of galaxy groups and clusters in two 25 deg ² fields. Combining spectroscopic and X-ray observations in one field, we determine how the kinetic energy of galaxies scales with hot gas temperature and also, by imposing prior constraints on the relative energies o...
Article
Full-text available
The evolution of the linear and scale independent bias, based on the most popular dark matter bias models within the $\Lambda$CDM cosmology, is confronted to that of the Dark Energy Survey (DES) Luminous Red Galaxies (LRGs). Applying a $\chi^2$ minimization procedure between models and data we find that all the considered linear bias models reprodu...
Article
Full-text available
The relationship between the integrated H$\beta$ line luminosity and the velocity dispersion of the ionized gas of HII galaxies and giant HII regions represents an exciting standard candle that presently can be used up to redshifts z ~ 4. Locally it is used to obtain precise measurements of the Hubble constant by combining the slope of the relation...
Article
Full-text available
The fraction of galaxies bound in groups in the nearby Universe is high (50% at z~0). Systematic studies of galaxy properties in groups are important in order to improve our understanding of the evolution of galaxies and of the physical phenomena occurring within this environment. We have built a complete spectrophotometric sample of galaxies withi...
Article
Full-text available
Modern cosmological simulations rely heavily on feedback from active galactic nuclei (AGN) in order to stave off overcooling in massive galaxies and galaxy groups and clusters. An important independent test is whether or not the simulations capture the broad demographics of the observed AGN population. Here, we have used the cosmo-OWLS suite of cos...
Article
Full-text available
The correlation between emission-line luminosity (L) and profile width (sigma) for HII Galaxies provides a powerful method to measure the distances to galaxies over a wide range of redshifts. In this paper we use SDSS spectrophotometry to explore the systematics of the correlation using the [OIII]5007 lines instead of Halpha or Hbeta to measure lum...
Article
Full-text available
The correlation between emission-line luminosity (L) and profile width (sigma) for HII Galaxies provides a powerful method to measure the distances to galaxies over a wide range of redshifts. In this paper we use SDSS spectrophotometry to explore the systematics of the correlation using the [OIII]5007 lines instead of Halpha or Hbeta to measure lum...
Article
We use the HII galaxies $L - \sigma$ relation and the resulting Hubble expansion cosmological probe of a sample of just 25 high-$z$ (up to $z \sim 2.33$) HII galaxies, in a joint likelihood analysis with other well tested cosmological probes (CMB, BAOs) in an attempt to constrain the dark energy equation of state (EoS). The constraints, although st...