48
48
Sep 20, 2013
09/13
by
M. Paolillo
texts
eye 48
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We present the study of three bright Early-Type galaxies hosted in groups or poor clusters: NGC 1399, NGC 1404 and NGC 507. We used ROSAT HRI, PSPC and, when available, higher resolution Chandra data to study the structure of the X-ray halo. The halo center of NGC 1399 and NGC 507 is dominated by a bright emission peak coincident with the position of the optical galaxy. This central peak is not explained by cooling flow models and is likely to be produced by kinetically heated stellar material....
Source: http://arxiv.org/abs/astro-ph/0204500v1
39
39
Sep 19, 2013
09/13
by
M. Spavone; E. Iodice; G. Longo; M. Paolillo
texts
eye 39
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We present a kinematical and photometrical study of a member, NGC4778, of the nearest (z=0.0137) compact group: Hickson 62. Our analysis reveals that Hickson 62a, also known as NGC4778, is an S0 galaxy with kinematical and morphological peculiarities, both in its central regions (r < 5'') and in the outer halo. In the central regions, the rotation curve shows the existence of a kinematically decoupled stellar component, offset with respect to the photometric center. In the outer halo we find...
Source: http://arxiv.org/abs/astro-ph/0701646v1
40
40
Sep 23, 2013
09/13
by
V. Allevato; M. Paolillo; I. Papadakis; C. Pinto
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eye 40
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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, assuming both a continuous and a sparse sampling pattern and various signal-to-noise (S/N) ratios. We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled lightcurves. The bias depends...
Source: http://arxiv.org/abs/1202.3786v5
53
53
Sep 23, 2013
09/13
by
M. Paolillo; G. Fabbiano; G. Peres; D. -W. Kim
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eye 53
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We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax cluster. Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple Beta model and suggests instead three distinct components. We use a multi-component bidimensional model to study in detail these three components that we identify respectively with the cooling flow region, the galactic and...
Source: http://arxiv.org/abs/astro-ph/0109342v1
44
44
Sep 22, 2013
09/13
by
M. Paolillo; G. Fabbiano; G. Peres; D. -W. Kim
texts
eye 44
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We present the preliminary results of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC1399 in the Fornax cluster. We find, in agreement with previous observations, an extended (41 Kpc adopting a distance of 19 Mpc) gaseous halo with a luminosity of L_X=(4.41\pm 0.04)x10^{41} erg/s. The 5 arcsec resolution of the data allows us to detect a very complex and asymmetric structure of the halo with respect to the optical galaxy. Moreover the analysis of the radial structure reveals the...
Source: http://arxiv.org/abs/astro-ph/0106309v1
131
131
Sep 23, 2013
09/13
by
M. Miranda; M. Sereno; E. De Filippis; M. Paolillo
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eye 131
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We perform a combined X-ray and strong lensing analysis of RX J1347.5-1145, one of the most luminous galaxy clusters at X-ray wavelengths. We show that evidence from strong lensing alone, based on published VLT and new HST data, strongly argues in favor of a complex structure. The analysis takes into account arc positions, shapes and orientations and is done thoroughly in the image plane. The cluster inner regions are well fitted by a bimodal mass distribution, with a total projected mass of...
Source: http://arxiv.org/abs/0801.1429v1
47
47
Sep 20, 2013
09/13
by
M. Sazhin; M. Capaccioli; G. Longo; M. Paolillo; O. Khovanskaya
texts
eye 47
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CSL-1 is a peculiar object (R.A._{2000}= 12h 23m 30.5"; Dec_{2000}= -12deg 38' 57.0") which, for its photometric and spectroscopic properties, is possibly the first case of gravitational lensing by a cosmic string. In this paper we present additional evidences, based on medium-high resolution VLT + FORS1 observations, that the spectra of the two components of CSL-1 are identical within a confidence level higher than 99.9% and the velocity difference of the two components is consistent...
Source: http://arxiv.org/abs/astro-ph/0506400v3
50
50
Sep 23, 2013
09/13
by
M. Brescia; S. Cavuoti; M. Paolillo; G. Longo; T. Puzia
texts
eye 50
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We present an application of self-adaptive supervised learning classifiers derived from the Machine Learning paradigm, to the identification of candidate Globular Clusters in deep, wide-field, single band HST images. Several methods provided by the DAME (Data Mining & Exploration) web application, were tested and compared on the NGC1399 HST data described in Paolillo 2011. The best results were obtained using a Multi Layer Perceptron with Quasi Newton learning rule which achieved a...
Source: http://arxiv.org/abs/1110.2144v2
5
5.0
Jun 29, 2018
06/18
by
F. Vagnetti; R. Middei; M. Antonucci; M. Paolillo; R. Serafinelli
texts
eye 5
favorite 0
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Most investigations of the X-ray variability of active galactic nuclei (AGN) have been concentrated on the detailed analyses of individual, nearby sources. A relatively small number of studies have treated the ensemble behaviour of the more general AGN population in wider regions of the luminosity-redshift plane. We want to determine the ensemble variability properties of a rich AGN sample, called Multi-Epoch XMM Serendipitous AGN Sample (MEXSAS), extracted from the fifth release of the...
Topics: Astrophysics, High Energy Astrophysical Phenomena, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1607.02629
49
49
Sep 18, 2013
09/13
by
M. Spavone; E. Iodice; G. Longo; M. Paolillo; S. Sodani
texts
eye 49
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Detailed studies of the photometric and kinematical properties of compact groups of galaxies are crucial to understand the physics of galaxy interactions and to shed light on some aspects of galaxy formation and evolution. In this paper we present a kinematical and photometrical study of a member, NGC4778, of the nearest (z=0.0137) compact group: Hickson 62. Aims: The aim of this work was to investigate the existence of kinematical anomalies in the brightest group member, NGC4778 in order to...
Source: http://arxiv.org/abs/astro-ph/0606730v2
55
55
Sep 21, 2013
09/13
by
R. D'Abrusco; A. Staiano; G. Longo; M. Paolillo; E. De Filippis
texts
eye 55
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Modern photometric multiband digital surveys produce large amounts of data that, in order to be effectively exploited, need automatic tools capable to extract from photometric data an objective classification. We present here a new method for classifying objects in large multi-parametric photometric data bases, consisting of a combination of a clustering algorithm and a cluster agglomeration tool. The generalization capabilities and the potentialities of this approach are tested against the...
Source: http://arxiv.org/abs/0706.4424v1
69
69
Sep 23, 2013
09/13
by
D. Capozzi; E. De Filippis; M. Paolillo; R. D'Abrusco; G. Longo
texts
eye 69
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We present a systematic study of the sub-sample of Shakhbazyan groups (SHKs) covered by the Sloan Digital Sky Survey Data Release--5 (SDSS-5). SHKs probe an environment with characteristics which are intermediate between those of loose and very compact groups. Surprisingly, we found that several groups identifying algorithms (e.g. Berlind et al. 2006, Tago et al. 2008) miss this type of structures. Using the SDSS-5 spectroscopic data and the photometric redshifts derived in D'Abrusco et al....
Source: http://arxiv.org/abs/0903.1093v2
54
54
Sep 19, 2013
09/13
by
S. Sodani; E. De Filippis; M. Paolillo; G. Longo; M. Spavone
texts
eye 54
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We studied the X-ray properties of the Hickson Compact Group HCG62, in order to determine the properties and dynamic and evolutionary state of its hot gaseous halo. Our analysis reveals that the X-ray diffuse halo has an extremely complex morphological, thermal and chemical structure. Two deep cavities, due to the presence of the AGN hosted by the central galaxy NGC 4778, are clearly visible in the group X-ray halo. The cavities appear to be surrounded by ridges of cool gas. The group shows a...
Source: http://arxiv.org/abs/astro-ph/0701616v1
48
48
Sep 18, 2013
09/13
by
E. Puddu; S. Andreon; G. Longo; V. Strazzullo; M. Paolillo; R. Gal
texts
eye 48
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By means of CCD photometry in three bands (Gunn g, r, i) we investigate the existence of 12 candidate clusters extracted via a model independent peak finding algorithm (\cite{memsait}) from DPOSS data. The derived color-magnitude diagrams allow us to confirm the physical nature of 9 of the cluster candidates, and to estimate their photometric redshifts. Of the other candidates, one is a fortuitous detection of a true cluster at z~0.4, one is a false detection and the last is undecidable on the...
Source: http://arxiv.org/abs/astro-ph/0110321v1
34
34
Sep 23, 2013
09/13
by
F. La Barbera; M. Paolillo; E. De Filippis; R. R. de Carvalho
texts
eye 34
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We present an X-ray follow-up, based on XMM plus Chandra, of six Fossil Group (FG) candidates identified in our previous work using SDSS and RASS data. Four candidates (out of six) exhibit extended X-ray emission, confirming them as true FGs. For the other two groups, the RASS emission has its origin as either an optically dull/X-ray bright AGN, or the blending of distinct X-ray sources. Using SDSS-DR7 data, we confirm, for all groups, the presence of an r-band magnitude gap between the seed...
Source: http://arxiv.org/abs/1202.4804v1
44
44
Sep 20, 2013
09/13
by
M. Paolillo; E. J. Schreier; R. Giacconi; A. M. Koekemoer; N. A. Grogin
texts
eye 44
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We studied the X-ray variability of sources detected in the Chandra Deep Field South (Giacconi et al. 2002), nearly all of which are low to moderate z AGN (Tozzi et al. 2001). We find that 45% of the sources with >100 counts exhibit significant variability on timescales ranging from a day up to a year. The fraction of sources found to be variable increases with observed flux, suggesting that >90% of all AGNs possess intrinsic variability. We also find that the fraction of variable sources...
Source: http://arxiv.org/abs/astro-ph/0404418v1
3
3.0
Jun 29, 2018
06/18
by
R. Middei; F. Vagnetti; S. Bianchi; F. La Franca; M. Paolillo; F. Ursini
texts
eye 3
favorite 0
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Variability in the X-rays is a key ingredient in understanding and unveiling active galactic nuclei (AGN) properties. In this band flux variations occur on short time scales (hours) as well as on larger times scales. While short time scale variability is often investigated in single source studies, only few works are able to explore flux variation on very long time scales.This work provides a statistical analysis of the AGN long term X-ray variability. We study variability on the largest time...
Topics: Astrophysics, High Energy Astrophysical Phenomena, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1612.08547
62
62
Sep 19, 2013
09/13
by
R. d'Abrusco; G. Longo; A. Staiano; E. de Filippis; M. Paolillo; M. Brescia
texts
eye 62
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We present a new analysis of the Sloan Digital Sky Survey data aimed at producing a detailed map of the nearby (z < 0.5) universe. Using neural networks trained on the available spectroscopic base of knowledge we derived distance estimates for about 30 million galaxies distributed over ca. 8,000 sq. deg. We also used unsupervised clustering tools developed in the framework of the VO-Tech project, to investigate the possibility to understand the nature of each object present in the field and,...
Source: http://arxiv.org/abs/astro-ph/0701135v2
117
117
Sep 17, 2013
09/13
by
V. Allevato; C. Pinto; M. Paolillo; I. Papadakis; P. Ranalli; A. Comastri; K. Iwasawa
texts
eye 117
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Recent work on nearby AGNs has shown that X-ray variability is correlated with the mass and accretion rate onto the central SMBH. Here we present the application of the variability-luminosity relation to high redshift AGNs in the CDFS, making use of XMM-Newton observations. We use Monte Carlo simulations in order to properly account for bias and uncertainties introduced by the sparse sampling and the very low statistics. Our preliminary results indicate that BH masses span over the range from...
Source: http://arxiv.org/abs/0912.0152v2
45
45
Sep 19, 2013
09/13
by
R. d'Abrusco; G. Longo; M. Paolillo; E. de Filippis; M. Brescia; A. Staiano; R. Tagliaferri
texts
eye 45
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In the framework of the European VO-Tech project, we are implementing new machine learning methods specifically tailored to match the needs of astronomical data mining. In this paper, we shortly present the methods and discuss an application to the Sloan Digital Sky Survey public data set. In particular, we discuss some preliminary results on the 3-D taxonomy of the nearby (z < 0.5) universe. Using neural networks trained on the available spectroscopic base of knowledge we derived distance...
Source: http://arxiv.org/abs/astro-ph/0701137v1
51
51
Sep 18, 2013
09/13
by
E. De Filippis; M. Paolillo; G. Longo; F. La Barbera; R. R. de Carvalho; R. Gal
texts
eye 51
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We present the analysis of the luminosity function of a large sample of galaxy clusters from the Northern Sky Optical Cluster Survey, using latest data from the Sloan Digital Sky Survey. Our global luminosity function (down to M_r
Source: http://arxiv.org/abs/1102.5310v1
3
3.0
Jun 30, 2018
06/18
by
M. Antonucci; A. Talavera; F. Vagnetti; D. Trevese; A. Comastri; M. Paolillo; P. Ranalli; C. Vignali
texts
eye 3
favorite 0
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The XMM-Newton X-ray observatory has repeatedly observed the CDFS in 33 epochs (2001-2010) through the XMM-CDFS Deep Survey. During the X-ray observations, XMM-OM targeted the central 17x17 arcmin2 region of the X-ray field of view, providing simultaneous optical/UV coverage of the CDFS. The resulting set of data can be used to build an XMM-OM catalogue of the CDFS, filling the UV spectral coverage between the optical surveys and GALEX observations. We present the UV catalogue of the XMM-CDFS...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1411.0502
74
74
Jul 20, 2013
07/13
by
S. Piranomonte; M. Paolillo; G. Longo; S. Andreon; E. Puddu; R. Scaramella; R. Gal; S. G. Djorgovski
texts
eye 74
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We present the composite luminosity function (hereafter LF) of galaxies for 80 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data in the framework of the CRoNaRio collaboration. Our determination of the LF has been computed with very high accuracy thanks to the use of homogeneous data both for the clusters and the control fields and to a local estimate of the background, which takes into account the presence of large-scale structures and of foreground clusters and...
Source: http://arxiv.org/abs/astro-ph/0009350v1
42
42
Sep 19, 2013
09/13
by
S. Piranomonte; M. Paolillo; S. Andreon; G. Longo; E. Puddu; R. Scaramella; R. Gal; S. G. Djorgovski
texts
eye 42
favorite 0
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We present the composite luminosity function (hereafter LF) of galaxies for 81 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data processed by the CRoNaRio collaboration. The derived LF is very accurate due to the use of homogeneous data both for the clusters and the control fields and to the local estimate of the background, which takes into account the presence of large-scale structures and of foreground clusters and groups. The global composite LF is quite flat...
Source: http://arxiv.org/abs/astro-ph/0010037v1
118
118
Jul 20, 2013
07/13
by
M. Paolillo; T. Puzia; S. E. Zepf; T. J. Maccarone; P. Goudfrooij; A. Kundu; G. Fabbiano; L. Angelini
texts
eye 118
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We present a wide field study of the Globular Clusters/Low Mass X-ray Binaries connection in the cD elliptical NGC1399, combining HST/ACS and Chandra high resolution data. We find evidence that LMXB formation likelihood is influenced by GCs structural parameters, in addition to the well known effects of mass and metallicity, independently from galactocentric distance.
Source: http://arxiv.org/abs/1007.0990v1
52
52
Sep 18, 2013
09/13
by
V. Strazzullo; M. Paolillo; G. Longo; E. Puddu; S. G. Djorgovski; R. R. De Carvalho; R. R. Gal
texts
eye 52
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The morphology of clusters of galaxies may be described with a set of parameters which contain information about the formation and evolutionary history of these systems. In this paper we present a preliminary study of the morphological parameters of a sample of 28 compact Abell clusters extracted from DPOSS data. The morphology of galaxy clusters is parameterized by their apparent ellipticity, position angle of the major axis, centre coordinates, core radius and beta-model power law index. Our...
Source: http://arxiv.org/abs/astro-ph/0502062v1
51
51
Sep 18, 2013
09/13
by
M. Paolillo; S. Andreon; G. Longo; E. Puddu; R. R. Gal; R. Scaramella; S. G. Djorgovski; R. de Carvalho
texts
eye 51
favorite 0
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The composite galaxy luminosity function (hereafter LF) of 39 Abell clusters of galaxies is derived by computing the statistical excess of galaxy counts in the cluster direction with respect to control fields. Due to the wide field coverage of the digitised POSS-II plates, we can measure field counts around each cluster in a fully homogeneous way. Furthermore, the availability of virtually unlimited sky coverage allows us to directly compute the LF errors without having to rely on the estimated...
Source: http://arxiv.org/abs/astro-ph/0012219v1
44
44
Sep 20, 2013
09/13
by
M. V. Sazhin; M. Capaccioli; G. Longo; M. Paolillo; O. S. Khovanskaya; N. A. Grogin; E. J. Schreier; G. Covone
texts
eye 44
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On January 12 2006, the Hubble Space Telescope observed the peculiar double extragalactic object CSL-1, suspected to be the result of gravitational lensing by a cosmic string. The high resolution image shows that the object is actually a pair of interacting giant elliptical galaxies. In spite of the weird similarities of the energy and light distributions and of the radial velocities of the two components, CSL-1 is not the lensing of an elliptical galaxy by a cosmic string.
Source: http://arxiv.org/abs/astro-ph/0601494v2
89
89
Sep 18, 2013
09/13
by
M. V. Sazhin; O. S. Khovanskaya; M. Capaccioli; G. Longo; M. Paolillo; G. Covone; N. A. Grogin; E. J. Schreier
texts
eye 89
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Cosmic strings were postulated by Kibble in 1976 and, from a theoretical point of view, their existence finds support in modern superstring theories, both in compactification models and in theories with extended additional dimensions. Their eventual discovery would lead to significant advances in both cosmology and fundamental physics. One of the most effective ways to detect cosmic strings is through their lensing signatures which appear to be significantly different from those introduced by...
Source: http://arxiv.org/abs/astro-ph/0611744v2
54
54
Sep 19, 2013
09/13
by
R. Gilli; P. Tozzi; P. Rosati; M. Paolillo; S. Borgani; M. Brusa; A. Comastri; E. Lusso; F. Marulli; C. Vignali
texts
eye 54
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We discuss some of the main open issues in the evolution of Active Galactic Nuclei which can be solved by the sensitive, wide area surveys to be performed by the proposed Wide Field X-ray Telescope mission.
Source: http://arxiv.org/abs/1010.6024v2
49
49
Sep 23, 2013
09/13
by
E. Puddu; S. Andreon; G. Longo; M. Paolillo; R. Scaramella; V. Testa; R. R. Gal; R. R. de Carvalho; S. G. Djorgovski
texts
eye 49
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We present preliminary results of a simple peak finding algorithm applied to catalogues of galaxies, extracted from the Second Palomar Sky Survey in the framework of the CRoNaRio project. All previously known Abell and Zwicky clusters in a test region of 5x5 sq. deg. are recovered and new candidate clusters are also detected. This algorithm represents an alternative way of searching for galaxy clusters with respect to that implemented and tested at Caltech on the same type of data (Gal et al....
Source: http://arxiv.org/abs/astro-ph/9909367v1
59
59
Sep 23, 2013
09/13
by
M. Paolillo; S. Andreon; G. Longo; E. Puddu; S. Piranomonte; R. Scaramella; V. Testa; R. R. de Carvalho; S. G. Djorgovski; R. R. Gal
texts
eye 59
favorite 0
comment 0
We present the composite luminosity function of galaxies for 24 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data in the framework of the CRoNaRio collaboration. Our determination of the luminosity function has been computed with very high accuracy thanks to 1) the use of homogeneous data both in the cluster and in the control field, 2) a local estimate of the background, which takes into account the presence of large-scale structures (which tipically make the...
Source: http://arxiv.org/abs/astro-ph/9909366v1
72
72
Sep 19, 2013
09/13
by
P. Rosati; S. Borgani; R. Gilli; M. Paolillo; P. Tozzi; S. Murray; R. Giacconi; A. Ptak; M. Weisskopf; W. Forman; C. Jones; the WFXT Team
texts
eye 72
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The Wide Field X-Ray Telescope (WFXT) is a medium-class mission designed to be 2-orders-of-magnitude more sensitive than any previous or planned X-ray mission for large area surveys and to match in sensitivity the next generation of wide-area optical, IR and radio surveys. Using an innovative wide-field X-ray optics design, WFXT provides a field of view of 1 square degree (10 times Chandra) with an angular resolution of 5" (Half Energy Width, HEW) nearly constant over the entire field of...
Source: http://arxiv.org/abs/1010.6252v1
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42
Sep 19, 2013
09/13
by
P. Tozzi; J. Santos; H. Yu; A. Bignamini; P. Rosati; S. Borgani; S. Campana; P. Conconi; R. Gilli; M. Paolillo; A. Ptak; the WFXT Team
texts
eye 42
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We investigate the scientific impact of the Wide Field X-ray Telescope mission. We present simulated images and spectra of X-ray sources as observed from the three surveys planned for the nominal 5-year WFXT lifetime. The goal of these simulations is to provide WFXT images of the extragalactic sky in different energy bands based on accurate description of AGN populations, normal and star forming galaxies, groups and clusters of galaxies. The images are realized using a detailed PSF model,...
Source: http://arxiv.org/abs/1010.6208v1
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47
Sep 18, 2013
09/13
by
M. Young; W. N. Brandt; Y. Q. Xue; M. Paolillo; D. M. Alexander; F. E. Bauer; B. D. Lehmer; B. Luo; O. Shemmer; D. P. Schneider; C. Vignali
texts
eye 47
favorite 1
comment 0
The 4 Ms Chandra Deep Field-South (CDF-S) and other deep X-ray surveys have been highly effective at selecting active galactic nuclei (AGN). However, cosmologically distant low-luminosity AGN (LLAGN) have remained a challenge to identify due to significant contribution from the host galaxy. We identify long-term X-ray variability (~month-years, observed frame) in 20 of 92 CDF-S galaxies spanning redshifts z~0.08-1.02 that do not meet other AGN selection criteria. We show that the observed...
Source: http://arxiv.org/abs/1201.4391v1
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67
Sep 18, 2013
09/13
by
G. Covone; M. Paolillo; N. R. Napolitano; M. Capaccioli; G. Longo; J. -P. Kneib; E. Jullo; J. Richard; O. Khovanskaya; M. Sazhin; N. A. Grogin; E. Schreier
texts
eye 67
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We analyze a new gravitational lens, OAC-GL J1223-1239, serendipitously found in a deep I-band image of the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The lens is a L_*, edge-on S0 galaxy at z=0.4656. The gravitational arc has a radius of 0.42 arcsec. We have determined the total mass and the dark matter (DM) fraction within the Einstein radius as a function of the lensed source redshift, which is presently unknown. For z ~ 1.3, which is in the middle of the redshift range...
Source: http://arxiv.org/abs/0809.4125v1
45
45
Sep 18, 2013
09/13
by
K. Iwasawa; R. Gilli; C. Vignali; A. Comastri; W. N. Brandt; P. Ranalli; F. Vito; N. Cappelluti; F. J. Carrera; S. Falocco; I. Georgantopoulos; V. Mainieri; M. Paolillo
texts
eye 45
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We present results on a search of heavily obscured active galaxies z>1.7 using the rest-frame 9-20 keV excess for X-ray sources detected in the deep XMM-CDFS survey. Out of 176 sources selected with the conservative detection criteria (>8 sigma) in the first source catalogue of Ranalli et al., 46 objects lie in the redshift range of interest with the median redshift z~2.5. Their typical rest-frame 10-20 keV luminosity is 1e+44 erg/s, as observed. Among optically faint objects that lack...
Source: http://arxiv.org/abs/1209.0916v1
116
116
Sep 23, 2013
09/13
by
S. Vattakunnel; P. Tozzi; F. Matteucci; P. Padovani; N. Miller; M. Bonzini; V. Mainieri; M. Paolillo; L. Vincoletto; W. N. Brandt; B. Luo; K. I. Kellermann; Y. Q. Xue
texts
eye 116
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In order to trace the instantaneous star formation rate at high redshift, and hence help understanding the relation between the different emission mechanisms related to star formation, we combine the recent 4 Ms Chandra X-ray data and the deep VLA radio data in the Extended Chandra Deep Field South region. We find 268 sources detected both in the X-ray and radio band. The availability of redshifts for $\sim 95$ of the sources in our sample allows us to derive reliable luminosity estimates and...
Source: http://arxiv.org/abs/1111.3285v1
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41
Sep 22, 2013
09/13
by
A. E. Hornschemeier; D. M. Alexander; F. E. Bauer; W. N. Brandt; R. Chary; C. Conselice; N. A. Grogin; A. M. Koekemoer; B. Mobasher; M. Paolillo; S. Ravindranath; E. J. Schreier
texts
eye 41
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We have identified a sample of 10 highly reliable off-nuclear (> 2 kpc) X-ray sources at z=0.03-0.25 in late-type host galaxies within the two GOODS fields (i.e., the two Chandra Deep Fields). The combination of the superb spatial resolution and great depth of the HST ACS and Chandra ACIS coverage in the GOODS fields is critical to the identification of these sources. We extend the study of this enigmatic population up to higher redshifts and larger look-back times than has been possible...
Source: http://arxiv.org/abs/astro-ph/0308408v1
11
11
Jun 28, 2018
06/18
by
N. R. Napolitano; G. Covone; N. Roy; C. Tortora; F. La Barbera; M. Radovich; F. Getman; M. Capaccioli; A. Colonna; M. Paolillo; G. A. Verdoes Kleijn; L. V. E. Koopmans; KiDS collaboration
texts
eye 11
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We have started a systematic search of strong lens candidates in the ESO public survey KiDS based on the visual inspection of massive galaxies in the redshift range $0.1
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1507.00733
7
7.0
Jun 29, 2018
06/18
by
G. Yang; W. Brandt; B. Luo; Y. Xue; F. Bauer; M. Sun; S. Kim; S. Schulze; X. Zheng; M. Paolillo; O. Shemmer; T. Liu; D. Schneider; C. Vignali; F. Vito; J. -X. Wang
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eye 7
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We perform long-term ($\approx 15$ yr, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6 Ms $Chandra$ Deep Field-South (CDF-S) survey; the majority are in the redshift range of $0.6-3.1$, providing access to penetrating rest-frame X-rays up to $\approx 10-30$ keV. Twenty-four of the 68 sources are optical spectral type I AGNs, and the rest (44) are type II AGNs. The time scales probed in this work are among the longest for X-ray...
Topics: Astrophysics, High Energy Astrophysical Phenomena, Astrophysics of Galaxies, Instrumentation and...
Source: http://arxiv.org/abs/1608.08224
7
7.0
Jun 29, 2018
06/18
by
E. Iodice; M. Capaccioli; A. Grado; L. Limatola; M. Spavone; N. R. Napolitano; M. Paolillo; R. F. Peletier; M. Cantiello; T. Lisker; C. Wittmann; A. Venhola; M. Hilker; R. D'Abrusco; V. Pota; P. Schipani
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eye 7
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[Abrigded] We have started a new deep, multi-imaging survey of the Fornax cluster, dubbed Fornax Deep Survey (FDS), at the VLT Survey Telescope. In this paper we present the deep photometry inside two square degrees around the bright galaxy NGC1399 in the core of the cluster. We found a very extended and diffuse envelope surrounding the luminous galaxy NGC1399: we map the surface brightness out to 33 arcmin (~ 192 kpc) from the galaxy center and down to about 31 mag/arcsec^2 in the g band. The...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1602.02149
4
4.0
Jun 30, 2018
06/18
by
M. Vaccari; G. Covone; M. Radovich; A. Grado; L. Limatola; M. T. Botticella; E. Cappellaro; M. Paolillo; G. Pignata; D. De Cicco; S. Falocco; L. Marchetti; M. Brescia; S. Cavuoti; G. Longo; M. Capaccioli; N. Napolitano; P. Schipani
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eye 4
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We present the VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey, a VST INAF Guaranteed Time program designed to provide optical coverage of two 4 deg$^2$ cosmic windows in the Southern hemisphere. VOICE provides the first, multi-band deep optical imaging of these sky regions, thus complementing and enhancing the rich legacy of longer-wavelength surveys with VISTA, Spitzer, Herschel and ATCA available in these areas and paving the way for upcoming observations with facilities such...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1704.01495
49
49
Sep 21, 2013
09/13
by
B. D. Lehmer; Y. Q. Xue; W. N. Brandt; D. M. Alexander; F. E. Bauer; M. Brusa; A. Comastri; R. Gilli; A. E. Hornschemeier; B. Luo; M. Paolillo; A. Ptak; O. Shemmer; D. P. Schneider; P. Tozzi; C. Vignali
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eye 49
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We present 0.5-2 keV, 2-8 keV, 4-8 keV, and 0.5-8 keV cumulative and differential number counts (logN-logS) measurements for the recently completed ~4 Ms Chandra Deep Field-South (CDF-S) survey, the deepest X-ray survey to date. We implement a new Bayesian approach, which allows reliable calculation of number counts down to flux limits that are factors of ~1.9-4.3 times fainter than the previously deepest number-counts investigations. In the soft band, the most sensitive bandpass in our...
Source: http://arxiv.org/abs/1204.1977v1
5
5.0
Jun 30, 2018
06/18
by
M. Symeonidis; A. Georgakakis; M. J. Page; J. Bock; M. Bonzini; V. Buat; D. Farrah; A. Franceschini; E. Ibar; D. Lutz; B. Magnelli; G. Magdis; S. J. Oliver; M. Pannella; M. Paolillo; D. Rosario; I. G. Roseboom; M. Vaccari; C. Villforth
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eye 5
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We present the most complete study to date of the X-ray emission from star-formation in high redshift (median z=0.7; z
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1407.4511
3
3.0
Jun 30, 2018
06/18
by
E. Iodice; M. Spavone; M. Capaccioli; R. F. Peletier; T. Richtler; M. Hilker; S. Mieske; L. Limatola; A. Grado; N. R. Napolitano; M. Cantiello; R. D'Abrusco; M. Paolillo; A. Venhola T. Lisker; G. van de Ven; J. Falcon-Barroso; P. Schipani
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eye 3
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As part of the Fornax Deep Survey with the ESO VLT Survey Telescope, we present new $g$ and $r$ bands mosaics of the SW group of the Fornax cluster. It covers an area of $3 \times 2$ square degrees around the central galaxy NGC1316. The deep photometry, the high spatial resolution of OmegaCam and the large covered area allow us to study the galaxy structure, to trace stellar halo formation and look at the galaxy environment. We map the surface brightness profile out to 33arcmin ($\sim 200$kpc...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1703.07989
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44
Sep 19, 2013
09/13
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N. A. Grogin; C. J. Conselice; E. Chatzichristou; D. M. Alexander; F. E. Bauer; A. E. Hornschemeier; S. Jogee; A. M. Koekemoer; V. G. Laidler; M. Livio; R. A. Lucas; M. Paolillo; S. Ravindranath; E. J. Schreier; B. D. Simmons; C. M. Urry
texts
eye 44
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We investigate morphological structure parameters and local environments of distant moderate-luminosity active galactic nucleus (AGN) host galaxies in the overlap between the HST/ACS observations of the Great Observatories Origins Deep Survey (GOODS) and the two Chandra Deep Fields. We compute near-neighbor counts and BViz asymmetry (A) and concentration (C) indices for ~35,500 GOODS/ACS galaxies complete to z_850 ~ 26.6, including the resolved hosts of 322 X-ray-selected AGNs. Distributions of...
Source: http://arxiv.org/abs/astro-ph/0507091v1
9
9.0
Jun 30, 2018
06/18
by
D. De Cicco; M. Paolillo; G. Covone; S. Falocco; G. Longo; A. Grado; L. Limatola; M. T. Botticella; G. Pignata; E. Cappellaro; M. Vaccari; D. Trevese; F. Vagnetti; M. Salvato; M. Radovich; W. N. Brandt; M. Capaccioli; N. R. Napolitano; P. Schipani
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eye 9
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Optical variability has proven to be an effective way of detecting AGNs in imaging surveys, lasting from weeks to years. In the present work we test its use as a tool to identify AGNs in the VST multi-epoch survey of the COSMOS field, originally tailored to detect supernova events. We make use of the multi-wavelength data provided by other COSMOS surveys to discuss the reliability of the method and the nature of our AGN candidates. Our selection returns a sample of 83 AGN candidates; based on a...
Topics: Astrophysics of Galaxies, High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1412.1488
5
5.0
Jun 29, 2018
06/18
by
R. D'Abrusco; M. Cantiello; M. Paolillo; V. Pota; N. R. Napolitano; L. Limatola; M. Spavone; A. Grado; E. Iodice; M. Capaccioli; R. Peletier; G. Longo; M. Hilker; S. Mieske; E. K. Grebel; T. Lisker; C. Wittmann; G. van de Ven; G. Fabbiano
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eye 5
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We report the discovery of a complex extended density enhancement in the Globular Clusters (GCs) in the central $\sim 0.5(^{\circ})^2$ ($\sim 0.06$ Mpc$^2$) of the Fornax cluster, corresponding to $\sim 50\%$ of the area within 1 core radius. This overdensity connects the GC system of NGC1399 to most of those of neighboring galaxies within $\sim 0.6^{\circ}$ ($\sim 210$ kpc) along the W-E direction. The asymmetric density structure suggests that the galaxies in the core of the Fornax cluster...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1602.06076
49
49
Sep 23, 2013
09/13
by
A. Vikhlinin; S. Murray; R. Gilli; P. Tozzi; M. Paolillo; N. Brandt; G. Tagliaferri; M. Bautz; S. Allen; M. Donahue; A. Evrard; K. Flanagan; P. Rosati; S. Borgani; R. Giacconi; M. Weisskopf; A. Ptak; D. Alexander; G. Pareschi; W. Forman; C. Jones
texts
eye 49
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Sensitive, wide-area X-ray surveys which would be possible with the WFXT will detect huge samples of virialized objects spanning the mass range from sub-groups to the most massive clusters, and extending in redshift to beyond z=2. These samples will be an excellent dataset for carrying out many traditional cosmological tests using the cluster mass function and power spectrum. Uniquely, WFXT will be able not only to detect clusters but also to make detailed X-ray measurements for a large number...
Source: http://arxiv.org/abs/0903.5320v1
