198 results on '"D'Abrusco, R."'
Search Results
152. IDENTIFICATION OF THE INFRARED NON-THERMAL EMISSION IN BLAZARS
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Massaro, F., primary, D'Abrusco, R., additional, Ajello, M., additional, Grindlay, J. E., additional, and Smith, Howard A., additional
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- 2011
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153. Nuclear activity and star formation properties of Seyfert 2 galaxies
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Rafanelli, P., primary, D’Abrusco, R., additional, Ciroi, S., additional, Cracco, V., additional, Di Mille, F., additional, and Vaona, L., additional
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- 2009
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154. The properties of the heterogeneous Shakhbazyan groups of galaxies in the SDSS
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Capozzi, D., primary, De Filippis, E., additional, Paolillo, M., additional, D'Abrusco, R., additional, and Longo, G., additional
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- 2009
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155. Quasar candidates selection in the Virtual Observatory era
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D'Abrusco, R., primary, Longo, G., additional, and Walton, N. A., additional
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- 2009
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156. Steps towards a map of the nearby universe
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D'Abrusco, R., primary, Longo, G., additional, Staiano, A., additional, de Filippis, E., additional, Paolillo, M., additional, and Brescia, M., additional
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- 2007
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157. Optical spectroscopic observations of γ-ray blazar candidates II. The 2013 KPNO campaign in the northern hemisphere.
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Massaro, F., Landoni, M., D'Abrusco, R., Milisavljevic, D., Paggi, A., Masetti, N., Smith, H. A., and Tosti, G.
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OPTICAL spectroscopy ,NORTHERN sky (Astronomy) ,BL Lacertae objects ,X-ray astronomy ,ASTRONOMICAL observations ,ASTROMETRIC telescopes - Abstract
Context. We recently started a systematic search of low-energy counterparts of the unidentified γ-ray sources (UGSs) listed in the Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) and the Fermi-LAT 2-Year Source Catalog (2FGL). Aims. The main goal of our investigation is to find active galaxies belonging to the blazar class that lie within the positional uncertainty region of the UGSs and thus could be their potential low-energy counterparts. Methods. To achieve our aims, we first adopted several procedures based on the peculiar observational properties of blazars in the radio and in the IR. Then we carried out a follow-up spectroscopic campaign in the optical band to verify the nature of the candidates selected as potential counterparts of the UGSs. Here we present the results of the observations carried out in 2013 in the northern hemisphere at Kitt Peak National Observatory (KPNO). Optical spectroscopy is crucial to confirm the nature of the sources and can be used to estimate their redshifts; it will also allow us to test the robustness of our methods when the whole campaign is completed. Results. Here we present the optical spectroscopic observations of 39 sources. Within our sample we found that 6 sources are blazars, candidates to be low-energy counterparts of the UGSs listed in the 2FGL.We confirm that an additional 8 sources, previously classified as active galaxies of uncertain type and associated in the 2FGL, are also all BL Lac objects. Moreover, we also present 20 new spectra for known blazars listed in the Multi-frequency Catalogue of Blazars as having an uncertain redshift and/or being classified as BL Lac candidates. Conclusions. We conclude that our methods for selecting γ-ray blazar candidates allows us to discover new blazars and increase the list of potential low-energy counterparts for the Fermi UGSs. [ABSTRACT FROM AUTHOR]
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- 2015
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158. THE RADIAL DISTRIBUTION OF X-RAY BINARIES AND GLOBULAR CLUSTERS IN NGC 4649 AND THEIR RELATION WITH THE LOCAL STELLAR MASS DENSITY.
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Mineo, S., Fabbiano, G., D'Abrusco, R., Fragos, T., Kim, D.-W., Strader, J., Brodie, J. P., Gallagher, J. S., Zezas, A., and Luo, B.
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X-ray binaries ,ELLIPTICAL galaxies ,STELLAR luminosity function ,X-ray astronomy ,BINARY stars - Abstract
We investigate the radial distribution of the low-mass X-ray binary (LMXB) population in the elliptical galaxy NGC 4649, using Chandra and Hubble data to separate the field and globular cluster (GC) populations. GCs with LMXBs have the same radial distribution as the parent red and blue GCs. The radial profile of field LMXBs follows the V-band profile within the D25 of NGC 4649. Using the spatial information provided by our data, we find that the global galaxy-wide relations among cumulative number and luminosity of LMXBs and the integrated stellar mass hold on local scales within D25. An excess of field LMXBs with respect to the V-band light is observed in the galaxy's outskirts, which may be partially due to unidentified GC sources or to a rejuvenated field LMXB population caused by past merging interactions. [ABSTRACT FROM AUTHOR]
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- 2014
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159. DAME: A Distributed Web Based Framework for Knowledge Discovery in Databases
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Brescia, M., Longo, G., Castellani, M., Stefano Cavuoti, D Abrusco, R., Laurino, O., Piercarlo Bonifacio, Brescia, M., Longo, G., Castellani, M., Cavuoti, S., D'Abrusco, R., Laurino, O., and M. Marconi, V. Andretta, E. Mazzotta Epifani, E. Cascone, E. Iodice
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distributed computing ,machine learning ,Astroinformatics, Data mining, Distributed computing, Machine learning, Virtual Observatory ,Astroinformatic ,data mining ,virtual observatory - Abstract
Massive data sets explored in many e-science communities, as in the Astrophysics case, are gathered by a very large number of techniques and stored in very diversified and often-incompatible data repositories. Moreover, we need to integrate services across distributed, heterogeneous, dynamic virtual organizations formed from the different resources within a single enterprise and/or from external resource sharing and service provider relationships. The DAME project aims at creating a distributed e-infrastructure to guarantee integrated and asynchronous access to data collected by very different experiments and scientific communities in order to correlate them and improve their scientific usability. The project consists of a data mining framework with powerful software instruments capable to work on massive data sets, organized by following Virtual Observatory standards, in a distributed computing environment. The integration process can be technically challenging because of the need to achieve a specific quality of service when running on top of different native platforms. In these terms, the result of the DAME project effort is a service-oriented architecture, by using appropriate standards and incorporating Cloud/Grid paradigms and Web services, that will have as main target the integration of interdisciplinary distributed systems within and across organizational domains.
160. The Chandra COSMOS Legacy Survey: A New Window to the Obscured and Distant Universe
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Civano, Francesca M., Elvis, M., Hasinger, G., Comastri, A., Harrison, F., Urry, C. M., Brusa, M., Zamorani, G., Cappelluti, N., Scoville, N., Eva Schinnerer, Donley, J., Allevato, V., Silverman, J., Treister, E., Capak, P. L., Aldcroft, T. L., Alexander, D., D Abrusco, R., Finoguenov, A., Fruscione, A., Glikman, E., Hao, H., Jahnke, K., Karim, A., Kartaltepe, J. S., Leauthaud, A., Lanzuisi, G., Miyaji, T., Vignali, C., Fiore, F., Puccetti, S., Ranalli, P., Smolcic, V., Riguccini, L., Sargent, M., Schawinski, K., Stern, D., Gilli, R., Civano, Francesca M., Elvis, M., Hasinger, G., Comastri, A., Harrison, F., Urry, C. M., Brusa, M., Zamorani, G., Cappelluti, N., Scoville, N., Schinnerer, E., Donley, J., Allevato, V., Silverman, J., Treister, E., Capak, P. L., Aldcroft, T. L., Alexander, D., D'Abrusco, R., Finoguenov, A., Fruscione, A., Glikman, E., Hao, H., Jahnke, K., Karim, A., Kartaltepe, J. S., Leauthaud, A., Lanzuisi, G., Miyaji, T., Vignali, C., Fiore, F., Puccetti, S., Ranalli, P., Smolcic, V., Riguccini, L., Sargent, M., Schawinski, K., Stern, D., and Gilli, R.
- Abstract
The equatorial 2 deg2 COSMOS area is the only large field for which a complete, deep, pan-chromatic data set exists, from an outstanding survey effort, and that all large telescopes can observe. Now, this pioneering and ambitious COSMOS survey is undergoing major extension, pushing its frontiers via the newly approved Chandra COSMOS Legacy Survey, the second largest Chandra proposal ever approved.'COSMOS-Legacy' will uniformly cover the 1.7 deg2 COSMOS/HST field with 2.8 Ms of Chandra ACIS-I imaging at ~160 ksec depth. This project expands the current deep C-COSMOS area by a factor of ~3 at ~3e-16 (1.45 vs 0.44 deg2). This will be achieved with 56x50 ks tiles covering a total area of 2.2 deg2, which will be observed during Chandra Cycle 14. The area and depth of COSMOS Legacy are designed to detect ~40 z>4, and ~4 z>5 Large Scale Structures on >15 arcmin scales. These structures have proven to connect luminous AGN (over 200 at z>3 will be detected) and sub-mm galaxies. COSMOS Legacy will also probe mini-quasars at z>7, using anistotropies of the unresolved X-ray Background, and the masses of the Dark Matter halos hosting X-ray AGN up to 3, via autocorrelation functions on ~30arcmin scales. To fully achieve these goals, COSMOS Legacy is complemented by spectroscopic follow-up with DEIMOS and MOSFIRE at Keck and KMOS at the VLT and FMOS at Subaru, just approved observations with Spitzer and JVLA, and with harder (5-80 keV) X-ray imaging with NuSTAR. In the near future, observations with Subaru HyperSuprimeCam (grizY) to r(AB)=28.2 are planned.
161. DAta Mining and Exploration (DAME): New Tools for Knowledge Discovery in Astronomy
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Djorgovski, Stanislav G., Longo, G., Brescia, M., Donalek, C., Cavuoti, S., Maurizio Paolillo, D Abrusco, R., Laurino, O., Mahabal, A., and Graham, M.
162. VizieR Online Data Catalog: WISE candidate γ-ray blazar radio sources (D'Abrusco+, 2014)
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D Abrusco, R., Massaro, F., Alessandro Paggi, Smith, H. A., Masetti, N., Landoni, M., and Tosti, G.
163. Confirming the gamma-ray blazar nature of the low energy counterpart QSO GB6 J1604+5714 of 2FGL J1604.6+5710 with WISE
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Massaro, F., D Abrusco, R., and Alessandro Paggi
164. A possible WISE blazar counterpart of the new GeV source Fermi J1350-1140
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Alessandro Paggi, Massaro, F., and D Abrusco, R.
165. VizieR Online Data Catalog: AGN automatic photometric classification (Cavuoti+, 2014)
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Cavuoti, S., Massimo Brescia, D Abrusco, R., Longo, G., and Paolillo, M.
166. VizieR Online Data Catalog: Blazars with γ-ray counterparts. I. (D'Abrusco+, 2013)
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D Abrusco, R., Massaro, F., Alessandro Paggi, Masetti, N., Tosti, G., Giroletti, M., and Smith, H. A.
167. Infrared counterparts of the two X-ray sources in the error circle of 2FGL J1551.9+0855
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Massaro, F., Cowperthwaite, P. S., Alessandro Paggi, and D Abrusco, R.
168. A Wise View Of The Non-thermal Gamma-ray Sky
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Massaro, Francesco, D Abrusco, R., Alessandro Paggi, Tosti, G., Ajello, M., and Gasaparrini, D.
169. The γ -ray sky seen at X-ray energies
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Marchesini, E. J., Paggi, A., Massaro, F., Masetti, N., D’Abrusco, R., Andruchow, I., and de Menezes, R.
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170. The footprint of large scale cosmic structure on the ultrahigh energy cosmic ray distribution.
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Cuoco, A., D’Abrusco, R., Longo, G., Miele, G., and Serpico, P. D.
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- 2006
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171. An Optical Overview of Blazars with LAMOST. II. Gamma-Ray Blazar Candidates and Updated Classifications
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H. A. Peña-Herazo, Minfeng Gu, N. Masetti, Alessandro Paggi, Federica Ricci, Francesco Massaro, Raffaele D'Abrusco, Marco Landoni, V. H. Chavushyan, Pena-Herazo, Ha, Massaro, F, Gu, Mf, Paggi, A, Landoni, M, D'Abrusco, R, Ricci, F, Masetti, N, Chavushyan, V, Peña-Herazo, H.A., Massaro, F., Gu, M., Paggi, A., Landoni, M., D'Abrusco, R., Ricci, F., Masetti, N., and Chavushyan, V.
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Physics ,Point source ,media_common.quotation_subject ,Gamma-ray sources (633) ,Astronomy and Astrophysics ,Astrophysics ,Flat-spectrum radio quasars (2163) ,Optical identification (1167) ,Redshift ,law.invention ,LAMOST ,Telescope ,Space and Planetary Science ,law ,Sky ,Spectroscopy (1558) ,BL Lacertae objects (158) ,Emission spectrum ,Blazar ,Blazars (164) ,media_common ,Fermi Gamma-ray Space Telescope - Abstract
Blazars represent the dominant class of associated γ-ray sources detected by the Fermi Large Area Telescope (LAT). However, in the more recent release of the Fourth Fermi-LAT Point Source Catalog (4FGL), ∼25% of the sources associated with lower-energy counterparts show a multifrequency behavior similar to that of blazars, but lacks an optical spectroscopic confirmation of their nature and are therefore classified as Blazar Candidates of Uncertain Type (BCUs). A particularly challenging task in blazar studies is to classify these BCUs and, when possible to estimate their redshifts, in particular for BL Lac objects, characterized by almost featureless optical spectra with only weak emission lines. Continuing our study of blazars with Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) optical spectral data, we perform an extensive search for optical spectra available in the LAMOST Data Release 6 archive. Our aim is confirming the blazar nature of BCUs and to test if new data can allow us to get a redshift estimate for BL Lac objects that lack measurement, as well as to search for and discover changing-look blazars. We selected sources out of the 4FGL catalog, the list of targets from our follow-up spectroscopic campaign of unidentified and/or unassociated γ-ray sources, and the Roma-BZCAT multifrequency catalog of blazars, finding a total of 42 sources with available LAMOST DR6 spectra. We confirmed the blazar-like nature of four blazar candidates . For the remaining 37 sources we confirm their previous classification. © 2021. The American Astronomical Society. All rights reserved.
- Published
- 2021
172. The Fornax Deep Survey with VST. IX. Catalog of sources in the FDS area with an example study for globular clusters and background galaxies
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Luca Limatola, Nicola R. Napolitano, Crescenzo Tortora, Aku Venhola, Massimo Quintini, Reynier Peletier, Michael Hilker, Aniello Grado, Fabrizio Gentile, Marilena Spavone, Massimo Capaccioli, Enrica Iodice, Jesus Falcon Barroso, Pietro Schipani, Gabriella Raimondo, Giovanni Covone, Maurizio Paolillo, Michele Cantiello, Glenn van de Ven, Steffen Mieske, Raffaele D'Abrusco, Astronomy, Cantiello M., Venhola A., Grado A., Paolillo M., D'Abrusco R., Raimondo G., Quintini M., Hilker M., Mieske S., Tortora C., Spavone M., Capaccioli M., Iodice E., Peletier R., Barroso J.F., Limatola L., Napolitano N., Schipani P., Van De Ven G., Gentile F., Covone G., Cantiello, M., Venhola, A., Grado, A., Paolillo, M., D'Abrusco, R., Raimondo, G., Quintini, M., Hilker, M., Mieske, S., Tortora, C., Spavone, M., Capaccioli, M., Iodice, E., Peletier, R., Barroso, J. F., Limatola, L., Napolitano, N., Schipani, P., Van De Ven, G., Gentile, F., and Covone, G.
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Population ,FOS: Physical sciences ,Context (language use) ,Astrophysics ,01 natural sciences ,cD ,Photometry (optics) ,0103 physical sciences ,Galaxy formation and evolution ,Fornax Cluster ,galaxies: elliptical and lenticular ,education ,010303 astronomy & astrophysics ,Physics ,education.field_of_study ,010308 nuclear & particles physics ,galaxies: clusters: individual: Fornax ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Galaxies: elliptical and lenticular, cD ,Stars ,galaxies: individual: NGC 1399 ,Space and Planetary Science ,Globular cluster ,Astrophysics of Galaxies (astro-ph.GA) ,galaxies: stellar content ,galaxies: evolution ,galaxies: individual: NGC 1316 - Abstract
This paper continues the series of the Fornax Deep Survey (FDS). Following the previous studies dedicated to extended Fornax cluster members, we present the catalogs of compact stellar systems in the Fornax cluster as well as extended background sources and point-like sources. We derive ugri photometry of ~1.7 million sources over the $\sim$21 sq. degree area of FDS centered on NGC1399. For a wider area, of $\sim$27 sq. degs extending in the direction of NGC1316, we provide gri data for ~3.1 million sources. To improve the morphological characterization of sources we generate multi-band image stacks by coadding the best seeing gri-band single exposures with a cut at FWHM, 25 pages, 18 figures, A&A accepted, tables 3-6 available on line
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- 2020
173. Optical spectroscopic observations of gamma-ray blazar candidates. X. Results from the 2018–2019 SOAR and OAN-SPM observations of blazar candidates of uncertain type
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H. A. Peña-Herazo, Raúl A. Amaya-Almazán, R. de Menezes, Alessandro Paggi, N. Masetti, Francesco Massaro, Elena Jiménez-Bailón, E. J. Marchesini, Howard A. Smith, Raffaele D'Abrusco, Dan Milisavljevic, G. Tosti, F. La Franca, C. C. Cheung, Federica Ricci, Marco Landoni, V. H. Chavushyan, de Menezes, R., Amaya-Almazan, R. A., Marchesini, E. J., Pena-Herazo, H. A., Massaro, F., Chavushyan, V., Paggi, A., Landoni, M., Masetti, N., Ricci, F., D'Abrusco, R., La Franca, F., Smith, H. A., Milisavljevic, D., Tosti, G., Jimenez-Bailon, E., Cheung, C. C., de Menezes R., Amaya-Almazan R. A., Marchesini E. J., Pena-Herazo H. A., Massaro F., Chavushyan V., Paggi A., Landoni M., Masetti N., Ricci F., D'Abrusco R., La Franca F., Smith H. A., Milisavljevic D., Tosti G., Jimenez-Bailon E., and Cheung C. C.
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active [Galaxies] ,Radiation mechanisms: non-thermal ,FOS: Physical sciences ,Galaxies: BL Lacertae objects ,Astrophysics ,Surveys ,01 natural sciences ,Galaxies: active ,Quasars: general ,law.invention ,purl.org/becyt/ford/1 [https] ,Telescope ,law ,Observatory ,0103 physical sciences ,Blazar ,010303 astronomy & astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,non-thermal [Radiation mechanisms] ,Gamma ray ,Astronomy and Astrophysics ,Quasar ,general [Quasars] ,purl.org/becyt/ford/1.3 [https] ,Galaxy ,Redshift ,Space and Planetary Science ,Galaxies: BL Lacertae object ,Astrophysics - High Energy Astrophysical Phenomena ,BL Lacertae object [Galaxies] ,BL LACERTAE OBJECTS [GALAXIES] ,Fermi Gamma-ray Space Telescope - Abstract
The fourth Fermi Large Area Telescope Source Catalog (4FGL) lists over 5000 gamma-ray sources with statistical significance above 4$\sigma$. About 23% of the sources listed in this catalog are unidentified/unassociated gamma-ray sources while ~26% of the sources are classified as blazar candidates of uncertain type (BCUs), lacking optical spectroscopic information. To probe the blazar nature of candidate counterparts of UGSs and BCUs, we started our optical spectroscopic follow up campaign in 2012, which up to date account for more than 350 observed sources. In this paper, the tenth of our campaign, we report on the spectroscopic observations of 37 sources, mostly BCUs, whose observations were carried out predominantly at the Observatorio Astron\'omico Nacional San Pedro M\'artir and the Southern Astrophysical Research Observatory between August 2018 and September 2019. We confirm the BL Lac nature of 27 sources and the flat spectrum radio quasar nature of three sources. The remaining ones are classified as six BL Lacs galaxy-dominated and one normal galaxy. We were also able to measure the redshifts for 20 sources, including 10 BL Lacs. As in previous analyses, the largest fraction of BCUs revealed to be BL Lac objects., Comment: 24 pages, 14 figures, 3 tables (Pre-proof version)
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- 2020
174. Optical spectroscopic observations of low-energy counterparts of Fermi -LAT γ -ray sources
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H. A. Peña-Herazo, C. C. Cheung, Raúl A. Amaya-Almazán, G. Tosti, Francesco Massaro, R. de Menezes, R. D'Abrusco, Elena Jiménez-Bailón, Alessandro Paggi, Howard A. Smith, Marco Landoni, V. H. Chavushyan, F. Ricci, Dan Milisavljevic, E. J. Marchesini, N. Masetti, Víctor M. Patiño-Álvarez, F. La Franca, Pena-Herazo H. A., Amaya-Almazan R. A., Massaro F., De Menezes R., Marchesini E. J., Chavushyan V., Paggi A., Landoni M., Masetti N., Ricci F., D'Abrusco R., Cheung C. C., La Franca F., Smith H. A., Milisavljevic D., Jimenez-Bailon E., Patino-Alvarez V. M., Tosti G., Pena-Herazo, H. A., Amaya-Almazan, R. A., Massaro, F., De Menezes, R., Marchesini, E. J., Chavushyan, V., Paggi, A., Landoni, M., Masetti, N., Ricci, F., D'Abrusco, R., Cheung, C. C., La Franca, F., Smith, H. A., Milisavljevic, D., Jimenez-Bailon, E., Patino-Alvarez, V. M., and Tosti, G.
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luminosity function, mass function [Galaxies] ,active [Galaxies] ,media_common.quotation_subject ,Population ,FOS: Physical sciences ,Astrophysics ,01 natural sciences ,law.invention ,Telescope ,emission lines [Quasars] ,Low energy ,law ,Galaxies: luminosity function ,0103 physical sciences ,Blazar ,education ,010303 astronomy & astrophysics ,media_common ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,education.field_of_study ,Quasars: emission lines ,general [BL Lacertae objects] ,010308 nuclear & particles physics ,Gamma ray ,Astronomy and Astrophysics ,BL Lacertae objects: general ,Galaxies: active ,Space and Planetary Science ,Sky ,mass function ,Astrophysics - High Energy Astrophysical Phenomena ,Data release ,Fermi Gamma-ray Space Telescope - Abstract
A significant fraction of all $\gamma$-ray sources detected by the Large Area Telescope aboard the \fer\ satellite is still lacking a low-energy counterpart. In addition, there is still a large population of $\gamma$-ray sources with associated low-energy counterparts that lack firm classifications. In the last 10 years we have undertaken an optical spectroscopic campaign to address the problem of unassociated/unidentified $\gamma$-ray sources (UGSs), mainly devoted to observing blazars and blazar candidates because they are the largest population of $\gamma$-ray sources associated to date. Here we describe the overall impact of our optical spectroscopic campaign on sources associated in \fer-LAT catalogs, coupled with objects found in the literature. In the literature search, we kept track of efforts by different teams that presented optical spectra of counterparts or potential counterparts of \fer-LAT catalog sources. Our summary includes an analysis of an additional 30 newly-collected optical spectra of counterparts or potential counterparts of \fer-LAT sources of previously unknown nature.New spectra were acquired at the Blanco 4-m and OAN-SPM 2.1-m telescopes, and those available in the Sloan Digital Sky Survey (data release 15) archive. All new sources with optical spectra analyzed here are classified as blazars. Thanks to our campaign, we altogether discovered and classified 394 targets with an additional 123 objects collected from a literature search. We began our optical spectroscopic campaign between the release of the second and third \fer-LAT source catalogs (2FGL and 3FGL, respectively), and classified about 25\% of the sources with uncertain nature and discovered a blazar-like potential counterpart for $\sim$10\% of UGSs listed therein. In the 4FGL catalog, about 350 \fer-LAT sources are classified to date thanks to our campaign. [incomplete abstract], Comment: 31 pages, 12 tables, 32 figures, 2 appendices, accepted for publication on A&A (pre-proofs version)
- Published
- 2020
175. Photometric redshifts for Quasars in multi band Surveys
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Raffaele D'Abrusco, Giuseppe Longo, Stefano Cavuoti, Massimo Brescia, Amata Mercurio, ITA, Brescia, M., Cavuoti, S., D'Abrusco, R., Longo, G., Mercurio, A., and D’Abrusco, R.
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catalog ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Radio galaxy ,media_common.quotation_subject ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Standard deviation ,Photometry (optics) ,quasars: general ,survey ,Median absolute deviation ,catalogs, galaxies: distances and redshifts, methods: data analysis, quasars: general, surveys, DIGITAL-SKY-SURVEY, 7TH DATA RELEASE, FUNCTION MINIMIZATION, CONJUGATE GRADIENTS, GALAXIES, SDSS, EVOLUTION, SELECTION, EXPLORER, MISSION ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,media_common ,Physics ,Astronomy and Astrophysics ,Quasar ,Redshift ,galaxies: distances and redshift ,Space and Planetary Science ,Sky ,Outlier ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysic ,methods: data analysi ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
MLPQNA stands for Multi Layer Perceptron with Quasi Newton Algorithm and it is a machine learning method which can be used to cope with regression and classification problems on complex and massive data sets. In this paper we give the formal description of the method and present the results of its application to the evaluation of photometric redshifts for quasars. The data set used for the experiment was obtained by merging four different surveys (SDSS, GALEX, UKIDSS and WISE), thus covering a wide range of wavelengths from the UV to the mid-infrared. The method is able i) to achieve a very high accuracy; ii) to drastically reduce the number of outliers and catastrophic objects; iii) to discriminate among parameters (or features) on the basis of their significance, so that the number of features used for training and analysis can be optimized in order to reduce both the computational demands and the effects of degeneracy. The best experiment, which makes use of a selected combination of parameters drawn from the four surveys, leads, in terms of DeltaZnorm (i.e. (zspec-zphot)/(1+zspec)), to an average of DeltaZnorm = 0.004, a standard deviation sigma = 0.069 and a Median Absolute Deviation MAD = 0.02 over the whole redshift range (i.e. zspec, 38 pages, Submitted to ApJ in February 2013; Accepted by ApJ in May 2013
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- 2013
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176. THE INFRARED–GAMMA-RAY CONNECTION: A WISE VIEW OF THE EXTRAGALACTIC GAMMA-RAY SKY
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D’Abrusco, R. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)]
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- 2016
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177. Optical Spectroscopic Observations of Gamma-ray Blazar Candidates. XI. Optical Observations from SOAR, Blanco, NTT and OAN-SPM. The Story so Far
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Marco Landoni, Fabio La Franca, Howard A. Smith, V. H. Chavushyan, Francesco Massaro, Federica Ricci, Elena Jiménez-Bailón, Dan Milisavljevic, Alessandro Paggi, N. Masetti, Raffaele D'Abrusco, Víctor M. Patiño-Álvarez, H. A. Peña-Herazo, E. J. Marchesini, Abigail García-Pérez, Gino Tosti, Raúl A. Amaya-Almazán, Pena-Herazo, H. A., Paggi, A., Garcia-Perez, A., Amaya-Almazan, R. A., Massaro, F., Ricci, F., Chavushyan, V., Marchesini, E. J., Masetti, N., Landoni, M., D'Abrusco, R., Milisavljevic, D., Jimenez-Bailon, E., Patino-Alvarez, V. M., La Franca, F., Smith, H. A., Tosti, G., Peña-Herazo, H.A., García-Pérez, A., Amaya-Almazán, R.A., Marchesini, E.J., Jiménez-Bailón, E., Patiño-Álvarez, V.M., and Smith, H.A.
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Optical identification, Blazars, BL Lacertae objects, Flat-spectrum radio quasars ,Gamma ray ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,extended figures ,Flat-spectrum radio quasars (2163) ,Optical identification (1167) ,Space and Planetary Science ,BL Lacertae objects (158) ,Optical identification ,Soar ,Blazar ,Blazars (164) ,Astrophysics::Galaxy Astrophysics - Abstract
Blazars represent about 62% of the sources in the ?-ray Fermi-LAT catalog, and about 80% of the ?-ray sources associated with a lower-energy counterpart, dominating the ?-ray sky. In particular, about 42% of the ?-ray blazars are classified as Blazars Candidates of Uncertain type (BCUs) for which spectroscopic observations are mandatory to confirm their blazar nature. Here we report the spectra of 64 targets observed as part of our follow-up optical spectroscopic campaign. This sample includes 62 sources classified in Fermi-LAT catalog as BCUs, one source classified as a generic active galactic nucleus, and one source classified as a BL Lac in Fermi-LAT and as blazar of uncertain type in the Roma-BZCAT catalog. We confirm the blazar nature of all BCUs. We classify 33 of them as BL Lacs, 11 as Flat Spectrum Radio Quasars, and 18 as blazars with nonnegligible host-galaxy emission. We also classify the generic active galactic nucleus as a BL Lac. Finally, we confirm the classification of the BL Lac. We also reported a lower limit redshift for 43 sources. For 20 sources, we got redshift measurements consistent with the literature values. For the other 21 sources, we obtained their first spectroscopic redshift measurement; while, for two sources, we provide lower limits on the redshift. With the upcoming release of the sixth edition of the Roma-BZCAT Multifrequency Catalog of Blazars, we take the opportunity in the present work to present the collective results of the first phase of our optical spectroscopic follow-up campaign. © 2021. The American Astronomical Society. All rights reserved..
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- 2021
178. Astroinformatics-based search for globular clusters in the Fornax Deep Survey
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Maurizio Paolillo, Reynier Peletier, Massimo Brescia, Enrichetta Iodice, V. Pota, Nicola R. Napolitano, Michele Cantiello, Giuseppe Angora, Thomas H. Puzia, Giuseppe D'Ago, Stefano Cavuoti, Marilena Spavone, Giuseppe Longo, Massimo Capaccioli, Raffaele D'Abrusco, Steffen Mieske, Giuseppe Riccio, Michael Hilker, Astronomy, Angora, G., Brescia, M., Cavuoti, S., Paolillo, M., Longo, G., Cantiello, M., Capaccioli, M., D'Abrusco, R., D'Ago, G., Hilker, M., Iodice, E., Mieske, S., Napolitano, N., Peletier, R., Pota, V., Puzia, T., Riccio, G., Spavone, M., ITA, USA, DEU, CHL, and NLD
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Neural gas ,Astroinformatics ,FOS: Physical sciences ,Feature selection ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,globular clusters: general ,CLASSIFICATION ,cD ,Photometry (optics) ,010104 statistics & probability ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,CORE ,NETWORK ,galaxies: elliptical and lenticular ,0101 mathematics ,Fornax Cluster ,Cluster analysis ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,VLT Survey Telescope ,business.industry ,Astronomy and Astrophysics ,Pattern recognition ,methods: data analysis ,Space and Planetary Science ,Globular cluster ,galaxies: elliptical and lenticular, cD ,FEATURE-SELECTION ,Artificial intelligence ,business ,Astrophysics - Instrumentation and Methods for Astrophysics ,methods: data analysis, globular clusters: general, galaxies: elliptical, Astrophysics - Instrumentation and Methods for Astrophysics ,SYSTEM - Abstract
In the last years, Astroinformatics has become a well defined paradigm for many fields of Astronomy. In this work we demonstrate the potential of a multidisciplinary approach to identify globular clusters (GCs) in the Fornax cluster of galaxies taking advantage of multi-band photometry produced by the VLT Survey Telescope using automatic self-adaptive methodologies. The data analyzed in this work consist of deep, multi-band, partially overlapping images centered on the core of the Fornax cluster. In this work we use a Neural-Gas model, a pure clustering machine learning methodology, to approach the GC detection, while a novel feature selection method ($\Phi$LAB) is exploited to perform the parameter space analysis and optimization. We demonstrate that the use of an Astroinformatics based methodology is able to provide GC samples that are comparable, in terms of purity and completeness with those obtained using single band HST data (Brescia et al. 2012) and two approaches based respectively on a morpho-photometric (Cantiello et al. 2018b) and a PCA analysis (D'Abrusco et al. 2015) using the same data discussed in this work., Comment: 29 pages, 14 figures
- Published
- 2019
179. Optical spectroscopic observations of gamma-ray blazar candidates. IX. Optical archival spectra and further observations from SOAR and OAGH
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Marco Landoni, Dan Milisavljevic, Alessandro Paggi, H. A. Peña-Herazo, Raffaele D'Abrusco, V. H. Chavushyan, F. La Franca, Federica Ricci, Gino Tosti, Francesco Massaro, Elena Jiménez-Bailón, E. J. Marchesini, N. Masetti, Howard A. Smith, Peña-Herazo, H. A., Massaro, F., Chavushyan, V., Marchesini, E. J., Paggi, A., Landoni, M., Masetti, N., Ricci, F., D’Abrusco, R., Milisavljevic, D., Jiménez-Bailón, E., La Franca, F., Smith, Howard A., and Tosti, G.
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Active galactic nucleus ,active [Galaxies] ,Radiation mechanisms: non-thermal ,media_common.quotation_subject ,Population ,FOS: Physical sciences ,Galaxies: BL Lacertae objects ,Astrophysics ,Surveys ,Galaxies: active ,Quasars: general ,01 natural sciences ,Cosmology ,Observatory ,0103 physical sciences ,Survey ,Blazar ,education ,010303 astronomy & astrophysics ,media_common ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,education.field_of_study ,non-thermal [Radiation mechanisms] ,Gamma ray ,general [Quasars] ,Astronomy and Astrophysics ,Quasar ,Astrophysics - Astrophysics of Galaxies ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,Galaxies: BL Lacertae object ,Astrophysics - High Energy Astrophysical Phenomena ,BL Lacertae object [Galaxies] - Abstract
Nearly one-third of the sources in the $Fermi$-LAT catalogs lack a lower energy counterpart, hence being referred as unidentified/unassociated gamma-ray sources (UGSs). In order to firmly classify them, dedicated multifrequency follow-up campaigns are necessary. These will permit to unveil their nature and identify the fraction that could belong to the class of active galaxies known as blazars that is the largest population of extragalactic $\gamma$-ray sources. In $Fermi$-LAT catalogs there are also gamma-ray sources associated with multifrequency blazar-like objects known as Blazars Candidates of Uncertain type (i.e., BCUs) for which follow up spectroscopic campaigns are mandatory to confirm their blazar nature. Thus, in 2013 we started an optical spectroscopic campaign to identify blazar-like objects potential counterparts of UGSs and BCUs. Here we report the spectra of 31 additional targets observed as part of our follow up campaign. Thirteen of them are BCUs for which we acquired spectroscopic observations at Observatorio Astrof\'isico Guillermo Haro (OAGH) and at Southern Astrophysical Research Observatory (SOAR) telescopes, while the rest has been identified thanks to the archival observations available from the Sloan Digital Sky Survey (SDSS). We confirm the blazar nature of all BCUs: three of them are in blazar of quasar type (BZQs) while the remaining ones can be spectroscopically classified as BL Lac objects (BZBs). Then we also discovered 18 BL Lac objects lying within the positional uncertainty regions of UGSs that could be their potential counterparts., Comment: 30 pages and 65 figures
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- 2019
180. The Fornax Deep Survey with the VST. V. Exploring the faintest regions of the bright early-type galaxies inside the virial radius
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G. van de Ven, Pietro Schipani, Enrica Iodice, Maurizio Paolillo, M. Capaccioli, Anna Pasquali, Jesús Falcón-Barroso, Aku Venhola, R. D'Abrusco, M. Cantiello, A. Grado, L. Limatola, Marilena Spavone, Nicola R. Napolitano, Reynier Peletier, S. Mieske, Michael Hilker, Rory Smith, Iodice, E., Spavone, M., Capaccioli, M., Peletier, R. ~F., van de Ven, G., Napolitano, N. ~R., Hilker, M., Mieske, S., Smith, R., Pasquali, A., Limatola, L., Grado, A., Venhola, A., Cantiello, M., Paolillo, M., Falcon-Barroso, J., D'Abrusco, R., Schipani, P., and Astronomy
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DWARF GALAXIES ,Stellar population ,TIDAL STREAMS ,FOS: Physical sciences ,Context (language use) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,cD ,STAR-FORMATION ,surveys ,GLOBULAR-CLUSTERS ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,INTRACLUSTER LIGHT ,Surface brightness ,QUANTITATIVE MORPHOLOGY ,Fornax Cluster ,galaxies: elliptical and lenticular ,individual ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,010308 nuclear & particles physics ,galaxies: clusters: individual: Fornax ,Astronomy and Astrophysics ,Radius ,Position angle ,VIRGO CLUSTER ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,KINEMATICALLY DISTINCT CORES ,galaxies: photometry ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Globular cluster ,Fornax ,SPIRAL GALAXIES ,MORPHOLOGY-DENSITY RELATION - Abstract
This paper is based on the multi-band (ugri) Fornax Deep Survey (FDS) with the VLT Survey Telescope (VST). We study bright early-type galaxies (m_B 28 mag/arcsec^2). Therefore, the new FDS data allow us to explore in great detail the morphology and structure of cluster galaxies out to the region of the stellar halo. The observations suggest that the Fornax cluster is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and GCs) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster., Accepted for publication in Astronomy & Astrophysics. High-resolution version of paper is available at the following link: https://www.dropbox.com/s/ybe4tg2hbqayteh/FDS_V.ETGs.pdf?dl=0
- Published
- 2019
181. Optical spectroscopic observations of gamma-ray blazar candidates VIII: the 2016–2017 follow up campaign carried out at SPM, NOT, KPNO and SOAR telescopes
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Marchesini, J., E., Pe��a-Herazo, A., H., Crespo, ��lvarez, Ricci, Negro, M., Milisavljevic, Massaro, Masetti, Landoni, Chavushyan, D'Abrusco, Jim��nez-Bail��n, Franca, La, Paggi, Smith, Tosti, Marchesini, E. J., Peña-Herazo, H. A., Álvarez Crespo, N., Ricci, F., Negro, M., Milisavljevic, D., Massaro, F., Masetti, N., Landoni, M., Chavushyan, V., D’Abrusco, R., Jiménez-Bailón, E., La Franca, F., Paggi, A., Smith, H. A., Tosti, G., ITA, and USA
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Active galactic nucleus ,active [Galaxies] ,FOS: Physical sciences ,Galaxies: BL Lacertae objects ,Astrophysics ,01 natural sciences ,Observatory ,0103 physical sciences ,Blazar ,010303 astronomy & astrophysics ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Line-of-sight ,Gamma ray ,Astronomy and Astrophysics ,Quasar ,general [Quasars] ,Galaxies: active ,Astronomy and Astrophysic ,Astrophysics - Astrophysics of Galaxies ,Quasars: general ,Redshift ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Galaxies: BL Lacertae object ,Astrophysics - High Energy Astrophysical Phenomena ,BL Lacertae object [Galaxies] ,Fermi Gamma-ray Space Telescope - Abstract
The third Fermi source catalog lists 3033 gamma-ray sources above $4\sigma$ significance. More than 30% are classified as either unidentified/unassociated Gamma-ray sources (UGSs), with about 20% classified as Blazar candidates of uncertain types (BCUs). To confirm the blazar-like nature of candidate counterparts of UGSs and BCUs, we started in 2012 an optical spectroscopic follow up campaign. We report here the spectra of 36 targets with observations from the Observatorio Astron\'omico Nacional San Pedro M\'artir, the Southern Astrophysical Research Observatory, the Kitt Peak National Observatory and the Northern Optical Telescope, between 2016 and 2017. We confirm the BL Lac nature of 23 sources, and the flat spectrum radio quasar nature of other 7 ones. We also provide redshift estimates for 19 out of these 30 confirmations, with only one being a lower limit due to spectral features ascribable to intervening systems along the line of sight. As in previous analyses, the largest fraction of now-classified BCUs belong to the class of BL Lac objects, that appear to be the most elusive class of active galactic nuclei. One of the BL Lacs identified in this work, associated with 3FGL J2213.6-4755, lies at a redshift of $z>$1.529, making it one of the few distant gamma-ray BL Lac objects., Comment: 29 pages, 2 tables, 36 figures, pre-proof version, published on 2019 Ap&SS, 364, 5
- Published
- 2019
182. Comparing X-ray color selection in separating X-ray binary classes using color-color-intensity diagrams.
- Author
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Islam, N., Vrtilek, S.D., Boroson, Bram, Kim, D.-W., O'Sullivan, E., McCollough, M.L., Fabbiano, G., Anderson, C., Burke, D.J., D'Abrusco, R., Fruscione, A., Lauer, J.L., Morgan, D., Mossman, A., Paggi, A., and Trinchieri, G.
- Subjects
- *
X-ray binaries , *BINARY black holes , *X-rays , *NEUTRON stars , *BLACK holes - Abstract
• Color-Color-Intensity diagrams are used for classifying X-ray binaries. • Different X-ray colors are tested for CCI diagrams of separate classes of XRBs. • X-ray binaries with black holes are separated from neutron stars in all X-ray colors. • Soft BH XRBs spectral states are separated in X-ray colors with lowest energyband. X-ray binaries exhibit a wide range of properties but there are few accepted methods to determine the nature of the compact object. Color-Color-Intensity diagrams have been suggested as a means of distinguishing between systems containing black holes from those containing neutron stars. However, this technique has been verified with data from only one instrument (RXTE/ASM) with a single set of X-ray colors defined using data available only in pre-determined energy bands. We test a selection of X-ray colors with a more sensitive instrument to determine the reliability of this method. We use data from the MAXI /Gas Slit Camera, which allows users to specify energy-bands. We test X-ray colors that have been previously defined in the literature as well as ones that we define specifically in this paper. A representative set of systems are used to construct Color-Color-Intensity diagrams in each set of colors to determine which are best for separating different classes. For studying individual sources certain bands are more effective than others. For a specified energy range, the separation of soft states in black hole binaries was possible only where both soft and hard colors included information from the lowest energy band. We confirm that Color-Color-Intensity diagrams can distinguish between systems containing black holes or neutron stars in all X-ray colors tested; this suggests an universality in the accretion processes governing these different classes. We suggest possible physical processes driving different classes of X-ray binaries to different locations in Color-Color-Intensity diagrams. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
183. The Fornax Cluster VLT Spectroscopic Survey. I - VIMOS spectroscopy of compact stellar systems in the Fornax core region
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R. Munoz, Raffaele D'Abrusco, Aaron J. Romanowsky, Crescenzo Tortora, Nicola R. Napolitano, Chiara Spiniello, R. E. Peletier, Vincenzo Pota, M. Capaccioli, Matthew A. Taylor, Michele Cantiello, C. Schulz, Paul Eigenthaler, Michael Hilker, Marilena Spavone, T. Lisker, Enrica Iodice, Thomas H. Puzia, G. van de Ven, Maurizio Paolillo, Mark A. Norris, Pietro Schipani, Y. Ordenes-Briceno, Ruben Sanchez-Janssen, Astronomy, Pota, V., Napolitano, N. R., Hilker, M., Spavone, M., Schulz, C., Cantiello, M., Tortora, C., Iodice, E., Paolillo, M., D'Abrusco, R., Capaccioli, M., Puzia, T., Peletier, R. F., Romanowsky, A. J., van de Ven, G., Spiniello, C., Norris, M., Lisker, T., Munoz, R., Schipani, P., Eigenthaler, P., Taylor, M. A., Sánchez-Janssen, R., and Ordenes-Briceño, Y.
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Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,ULTRACOMPACT DWARF GALAXIES ,NGC-1399 ,Population ,FOS: Physical sciences ,galaxies:evolution ,F800 ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Galaxies: kinematics and dynamic ,NGC 1399 ,GLOBULAR-CLUSTERS ,0103 physical sciences ,EARLY-TYPE GALAXIES ,Astrophysics::Solar and Stellar Astrophysics ,Surface brightness ,Fornax Cluster ,education ,010303 astronomy & astrophysics ,galaxies: kinematics and dynamics ,POPULATION ,Astrophysics::Galaxy Astrophysics ,Physics ,education.field_of_study ,010308 nuclear & particles physics ,Velocity dispersion ,Astronomy and Astrophysics ,Astronomy and Astrophysic ,Planetary nebula ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Radial velocity ,VIRGO ,COSMOLOGICAL SIMULATIONS ,13. Climate action ,Space and Planetary Science ,Globular cluster ,Astrophysics of Galaxies (astro-ph.GA) ,PLANETARY-NEBULAE ,SIGHT VELOCITY DISTRIBUTIONS ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the results of a wide spectroscopic survey aimed at detecting extragalactic globular clusters (GCs) in the core of the Fornax cluster. About 4500 low resolution spectra (from 4800 to 10000 \AA ) were observed in 25 VLT/VIMOS masks covering the central 1 deg$^{2}$ around the dominant galaxy NGC 1399 corresponding to $\sim$175 kpc galactocentric radius. We describe the methodology used for data reduction and data analysis. We found a total of 387 unique physical objects (372 GCs and 15 ultra compact dwarfs) in the field covered by our observations. Most of these objects are associated with NGC 1399, with only 10% likely belonging to other giant galaxies. The new VIMOS dataset is complementary to the many GC catalogues already present in the literature and it brings the total number of tracer particles around NGC 1399 to more than 1130 objects. With this comprehensive radial velocity sample we have found that the velocity dispersion of the GC population (equally for red and blue GC populations) shows a relatively sharp increase from low velocity dispersion ($\sim250$-$350$ kms$^{-1}$) to high velocity dispersion ($\sim300$-$400$ kms$^{-1}$) at projected radius of $\approx10$ arcmin ($\sim60$ kpc) from the galaxy centre. This suggests that at a projected radius of $\approx60$ kpc both blue and red GC populations begin to be governed by the dominating Fornax cluster potential, rather than by the central NGC 1399 galaxy potential. This kinematic evidence corroborates similar results found using surface brightness analysis and planetary nebulae kinematics., Comment: 13 pages, 9 figures, submitted to MNRAS, companion paper FVSS-II (Spiniello et al. 2018, submitted)
- Published
- 2018
- Full Text
- View/download PDF
184. Optical Spectroscopic Observations of Gamma-Ray Blazar Candidates. VII. Follow-up Campaign in the Southern Hemisphere
- Author
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Peña-Herazo, A., H., Marchesini, J., E., Crespo, Álvarez, Ricci, Massaro, Chavushyan, Landoni, Strader, Chomiuk, Cheung, C., C., Masetti, Jiménez-Bailón, D'Abrusco, Paggi, Milisavljevic, Franca, La, Smith, Tosti, Pena-Herazo, H. A., Marchesini, E. J., Ã lvarez Crespo, N., Ricci, F., Massaro, F., Chavushyan, V., Landoni, M., Strader, J., Chomiuk, L., Cheung, C. C., Masetti, N., Jimenez-Bailon, E., D'Abrusco, R., Paggi, A., Milisavljevic, D., La Franca, F., Smith, H. A., Tosti, G., ITA, USA, ARG, CAN, COL, and MEX
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Ciencias Astronómicas ,active [Galaxies] ,Ciencias Físicas ,FOS: Physical sciences ,Galaxies: BL Lacertae objects ,Astrophysics ,010501 environmental sciences ,01 natural sciences ,law.invention ,Telescope ,Low energy ,law ,0103 physical sciences ,Blazar ,010303 astronomy & astrophysics ,Southern Hemisphere ,0105 earth and related environmental sciences ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Gamma ray ,Galaxies: active ,Quasars: general ,Astronomy and Astrophysics ,Space and Planetary Science ,general [Quasars] ,Astronomy and Astrophysic ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Astronomía ,Astrophysics of Galaxies (astro-ph.GA) ,Galaxies: BL Lacertae object ,BL Lacertae object [Galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,BL LACERTAE OBJECTS [GALAXIES] ,CIENCIAS NATURALES Y EXACTAS ,Fermi Gamma-ray Space Telescope - Abstract
Searching for low energy counterparts of gamma-ray sources is one of the major challenges in modern gamma-ray astronomy. In the third Fermi source catalog about 30 % of detected sources are unidentified/unassociated Gamma-ray Sources (UGSs). We recently started an optical spectroscopic follow up campaign to confirm the blazar-like nature of candidates counterparts of UGSs. Here we report the spectra of 61 targets collected with the Southern Astrophysical Research Telescope (SOAR) between 2014 and the 2017. Our sample includes 33 potential counterparts of UGSs, selected on the basis of WISE colors, and 27 blazar candidates of uncertain type associated with gamma-ray sources of the last release of the Fermi catalog. We confirm the BZB nature of 20 sources lying within the positional uncertainty region of the UGSs. All the observed BCUs show blazar-like spectra, classified as 2 BZQs and 25 BZBs, for which we obtained 6 redshift estimates. Within the BCUs observations we report the redshift estimate for the BZB associated with, 3FGL J1106.4-3643 that is the second most distant BL Lac known to date, at z>1.084., 38 pages, 1 table, 61 figures, pre-proof version, published on 2017 Ap&SS, 362, 228
- Published
- 2017
185. Intra-cluster patches of baryons in the core of the Fornax cluster
- Author
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Michael Hilker, A. Grado, L. Limatola, Nicola R. Napolitano, Raffaele D'Abrusco, Steffen Mieske, Aku Venhola, G. van de Ven, E. Iodice, Pietro Schipani, Reynier Peletier, Maurizio Paolillo, Marilena Spavone, Michele Cantiello, Massimo Capaccioli, Astronomy, Iodice, E., Spavone, M., Cantiello, M., D'Abrusco, R., Capaccioli, M., Hilker, M., Mieske, S., Napolitano, N. R., Peletier, R. F., Limatola, L., Grado, A., Venhola, A., Paolillo, M., Ven, G. Van De, and Schipani, P.
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galaxies: clusters: intracluster medium ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Luminosity ,0103 physical sciences ,Cluster (physics) ,galaxies: interactions ,Astrophysics::Solar and Stellar Astrophysics ,Fornax Cluster ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,education.field_of_study ,interactions [galaxies] ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astronomy and Astrophysic ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Stars ,clusters: intracluster medium [galaxies] ,Space and Planetary Science ,galaxies: interaction ,Astrophysics of Galaxies (astro-ph.GA) ,Globular cluster ,Halo - Abstract
In the core of the Fornax cluster, on the West side of NGC1399, we have detected a previously unknown region of intra-cluster light (ICL). It is made up by several faint ($\mu_r \simeq 28 - 29$~mag/arcsec$^2$) {\it patches} of diffuse light. The bulk of the ICL is located in between the three bright galaxies in the core, NGC1387, NGC1379 and NGC1381, at $10\leq R \leq40$~arcmin ($\sim 58 - 230$~kpc) from the central galaxy NGC~1399. We show that the ICL is the counterpart in the diffuse light of the known over-density in the population of blue globular clusters (GCs). The total g-band luminosity of the ICL is $L_g\simeq 8.3 \times 10^{9}$ $L_{\odot}$, which is $\sim5\%$ of the total luminosity of NGC1399. This is consistent with the fraction of the blue GCs in the same region of the cluster. The ICL has $g-r \sim 0.7$~mag, which is similar to the colors in the halo of the bright galaxies in the cluster core. The new findings were compared with theoretical predictions for the ICL formation and they support a scenario in which the intra-cluster population detected in the core of the Fornax cluster is build up by the tidal stripping of material (stars and GCs) from galaxy outskirts in a close passage with the cD. Moreover, the diffuse form of the ICL and its location close to the core of the cluster is expected in a dynamically evolved cluster as Fornax., Comment: Accepted for publication in ApJ
- Published
- 2017
186. Optical archival spectra of blazar candidates of uncertain type in the 3rd Fermi Large Area Telescope Catalog
- Author
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Elena Jiménez-Bailón, Víctor M. Patiño-Álvarez, N. Álvarez Crespo, N. Masetti, Francesco Massaro, Howard A. Smith, Dan Milisavljevic, R. D'Abrusco, Alessandro Paggi, F. La Franca, Marco Landoni, V. H. Chavushyan, F. Ricci, Álvarez Crespo, N., Massaro, F., D’Abrusco, R., Landoni, M., Masetti, N., Chavushyan, V., Jiménez Bailón, E., LA FRANCA, Fabio, Milisavljevic, D., Paggi, A., Patiño Álvarez, V., RICCI, FEDERICA, Smith, Howard A., and Ricci, Federica
- Subjects
Active galactic nucleus ,active [Galaxies] ,Radiation mechanisms: non-thermal ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,FOS: Physical sciences ,Galaxies: BL Lacertae objects ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxies: active ,Astronomy and Astrophysics ,Space and Planetary Science ,010501 environmental sciences ,01 natural sciences ,law.invention ,Telescope ,law ,0103 physical sciences ,education ,Blazar ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,High Energy Astrophysical Phenomena (astro-ph.HE) ,astro-ph.HE ,Physics ,Field galaxy ,education.field_of_study ,non-thermal [Radiation mechanisms] ,Quasar ,Astronomy and Astrophysic ,Galaxy ,Galaxies: BL Lacertae object ,BL Lacertae object [Galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope - Abstract
Despite the fact that blazars constitute the rarest class among active galactic nuclei (AGNs) they are the largest known population of associated $\gamma$-ray sources. Many of the $\gamma$-ray objects listed in the Fermi-Large Area Telescope Third Source catalog (3FGL) are classified as blazar candidates of uncertain type (BCUs), either because they show multifrequency behaviour similar to blazars but lacking optical spectra in the literature, or because the quality of such spectra is too low to confirm their nature. Here we select, out of 585 BCUs in the 3FGL, 42 BCUs which we identify as probable blazars by their WISE infrared colors and which also have optical spectra that are available in the Sloan Digital Sky Survey (SDSS) and/or Six-Degree Field Galaxy Survey Database (6dFGS). We confirm the blazar nature of all of the sources. We furthermore conclude that 28 of them are BL Lacs, 8 are radio-loud quasars with flat radio spectrum and 6 are BL Lac whose emission is dominated by their host galaxy.
- Published
- 2016
187. Optical Spectroscopic Observations of Gamma-ray Blazar Candidates. V. TNG, KPNO, and OAN Observations of Blazar Candidates of Uncertain Type in the Northern Hemisphere
- Author
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Federica Ricci, Elena Jiménez-Bailón, Marco Landoni, Gino Tosti, Francesco Massaro, Howard A. Smith, J. Torrealba, L. Latronico, Raffaele D'Abrusco, Alessandro Paggi, N. Álvarez Crespo, F. La Franca, N. Masetti, V. H. Chavushyan, Víctor M. Patiño-Álvarez, ITA, USA, Álvarez Crespo, N., Masetti, N., Ricci, Federica, Landoni, M., Patiño Álvarez, V., Massaro, F., D'Abrusco, R., Paggi, A., Chavushyan, V., Jiménez Bailón, E., Torrealba, J., Latronico, L., LA FRANCA, Fabio, Smith, Howard A., Tosti, G., and RICCI, FEDERICA
- Subjects
Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,galaxies: active ,FOS: Physical sciences ,BL Lacertae objects: general ,radiation mechanisms: non-thermal ,BL Lacertae objects: general , galaxies: active , radiation mechanisms: non-thermal ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Observatory ,0103 physical sciences ,Emission spectrum ,Blazar ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,general [BL Lacertae objects] ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Quasar ,non-thermal [radiation mechanisms] ,Redshift ,Galaxy ,Space and Planetary Science ,active [galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope - Abstract
The extragalactic $\gamma$-ray sky is dominated by emission from blazars, a peculiar class of active galactic nuclei (AGNs). Many of the $\gamma$-ray sources included in Fermi -Large Area Telescope Third Source catalog (3FGL) are classified as a blazar candidate of uncertain type (BCU) because there is no optical spectra available in the literature to confirm their nature. In 2013 we started a spectroscopic campaign to look for the optical counterparts of the BCUs and of the Unidentified $\gamma$-ray Sources. The main goal of our investigation is to confirm the blazar nature of these sources having peculiar properties as compact radio emission and/or selected on the basis of their infrared (IR) colors. Whenever possible we also determine their redshifts. Here we present the results of the observations carried out in the Northern hemisphere in 2013 and 2014 at Telescopio Nazionale Galilleo (TNG), Kitt Peak National Observatory (KPNO) and Observatorio Astron\'omico Nacional (OAN) in San Pedro M\'artir. In this paper we describe the optical spectra of 25 sources. We confirmed that all the 15 BCUs observed in our campaign and included in our sample are blazars and we estimated the redshift for 3 of them. In addition, we present the spectra for 3 sources classified as BL Lacs in the literature but with no optical spectra available to date. We found that one of them is a quasar (QSO) at a redshift $z$ = 0.208 and the other 2 are BL Lacs. Moreover, we also present 7 new spectra for known blazars listed in the Roma-BZCAT having an uncertain redshift or being classified as BL Lac candidates. We found that one of them, 5BZB J0724+2621 is a `changing look' blazar. According to the spectrum available in the literature it was classified as a BL Lac but in our observation we clearly detected a broad emission line that lead to classify this source as a QSO at $z$=1.17., Comment: 21 pages, 26 figures, 3 tables, pre-proof version, published on the Astronomical Journal. arXiv admin note: text overlap with arXiv:1503.04202
- Published
- 2016
188. OPTICAL SPECTROSCOPIC OBSERVATIONS OF GAMMA-RAY BLAZAR CANDIDATES. VI. FURTHER OBSERVATIONS FROM TNG, WHT, OAN, SOAR, AND MAGELLAN TELESCOPES
- Author
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M. Kagaya, Víctor M. Patiño-Álvarez, Marco Landoni, Francesco Massaro, Federica Ricci, Laura Chomiuk, Hideaki Katagiri, Raffaele D'Abrusco, V. H. Chavushyan, N. Masetti, F. La Franca, Dan Milisavljevic, Jay Strader, Elena Jiménez-Bailón, Howard A. Smith, Gino Tosti, C. C. Cheung, N. Álvarez Crespo, Alessandro Paggi, Álvarez Crespo, N., Massaro, F., Milisavljevic, D., Landoni, M., Chavushyan, V., Patiño Álvarez, V., Masetti, N., Jiménez Bailón, E., Strader, J., Chomiuk, L., Katagiri, H., Kagaya, M., Cheung, C. C., Paggi, A., D'Abrusco, R., Ricci, Federica, LA FRANCA, Fabio, Smith, Howard A., Tosti, G., ITA, USA, and RICCI, FEDERICA
- Subjects
ACTIVE GALACTIC NUCLEI ,RADIO-SOURCES ,Active galactic nucleus ,SAMPLE ,010504 meteorology & atmospheric sciences ,active [Galaxies] ,Young stellar object ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,galaxies: active ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,MHZ ,BL Lacertae objects: general ,quasars: general ,radiation mechanisms: non-thermal ,GHZ ,0103 physical sciences ,Emission spectrum ,Blazar ,education ,SOURCE CATALOG ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Physics ,education.field_of_study ,non-thermal [Radiation mechanisms] ,general [BL Lacertae objects] ,Gamma ray ,Quasar ,Astronomy and Astrophysics ,general [Quasars] ,COUNTERPARTS ,Space and Planetary Science ,ALL-SKY SURVEY ,OBJECTS ,Astrophysics - High Energy Astrophysical Phenomena ,EMISSION ,Fermi Gamma-ray Space Telescope - Abstract
Indexación: Web of Science Blazars, one of the most extreme classes of active galaxies, constitute so far the largest known population of.-ray sources, and their number is continuously growing in the Fermi catalogs. However, in the latest release of the Fermi catalog there is still a large fraction of sources that are classified as blazar candidates of uncertain type (BCUs) for which optical spectroscopic observations are necessary to confirm their nature and their associations. In addition, about one-third of the gamma-ray point sources listed in the Third Fermi-LAT Source Catalog (3FGL) are still unassociated and lacking an assigned lower-energy counterpart. Since 2012 we have been carrying out an optical spectroscopic campaign to observe blazar candidates to confirm their nature. In this paper, the sixth of the series, we present optical spectroscopic observations for 30 gamma-ray blazar candidates from different observing programs we carried out with the Telescopio Nazionale Galileo, William Herschel Telescope, Observatorio Astronomico Nacional, Southern Astrophysical Research Telescope, and Magellan. Telescopes. We found that 21 out of 30 sources investigated are BL Lac objects, while the remaining targets are classified as flat-spectrum radio quasars showing the typical broad emission lines of normal quasi-stellar objects. We conclude that our selection of gamma-ray blazar. candidates based on their multifrequency properties continues to be a successful way to discover potential low-energy counterparts of the Fermi. unidentified gamma-ray sources and to confirm the nature of BCUs. http://iopscience.iop.org/article/10.3847/0004-6256/151/4/95/meta
- Published
- 2016
189. The gamma-ray blazar quest: new optical spectra, state of art and future perspectives
- Author
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Massaro, F., Álvarez, Crespo, D’Abrusco, N., Landoni, R., Masetti, M., Ricci, N., Milisavljevic, F., Paggi, D., Chavushyan, A., Jiménez Bailón, V., Patiño Álvarez, E., Strader, V., Chomiuk, J., La Franca, L., Smith, F., Tosti, H. A., Tosti, Gino, Massaro, F., Álvarez Crespo, N., D’Abrusco, R., Landoni, M., Masetti, N., RICCI, FEDERICA, Milisavljevic, D., Paggi, A., Chavushyan, V., Jiménez Bailón, E., Patiño Álvarez, V., Strader, J., Chomiuk, L., LA FRANCA, Fabio, Smith, Howard A., Tosti, G., and Ricci, Federica
- Subjects
active [Galaxies] ,Radiation mechanisms: non-thermal ,Infrared ,media_common.quotation_subject ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Galaxies: BL Lacertae objects ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Surveys ,01 natural sciences ,Galaxies: active ,Quasars: general ,Spectral line ,Astronomy and Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Survey ,Blazar ,010303 astronomy & astrophysics ,media_common ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,non-thermal [Radiation mechanisms] ,010308 nuclear & particles physics ,Gamma ray ,general [Quasars] ,Astronomy and Astrophysic ,Optical spectra ,Sky ,Galaxies: BL Lacertae object ,State of art ,BL Lacertae object [Galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope - Abstract
We recently developed a procedure to recognize gamma-ray blazar candidates within the positional uncertainty regions of the unidentified/unassociated gamma-ray sources (UGSs). Such procedure was based on the discovery that Fermi blazars show peculiar infrared colors. However, to confirm the real nature of the selected candidates, optical spectroscopic data are necessary. Thus, we performed an extensive archival search for spectra available in the literature in parallel with an optical spectroscopic campaign aimed to reveal and confirm the nature of the selected gamma-ray blazar candidates. Here, we first search for optical spectra of a selected sample of gamma-ray blazar candidates that can be potential counterparts of UGSs using the Sloan Digital Sky Survey (SDSS DR12). This search enables us to update the archival search carried out to date. We also describe the state-of-art and the future perspectives of our campaign to discover previously unknown gamma-ray blazars., Comment: 11 pages, 2 figures, 5 tables, pre-proof version, accepted for publication of Astrophysics and Space Science
- Published
- 2016
190. A Bibliometric Analysis of Observatory Publications 2011-2015
- Author
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Dennis R. Crabtree, Lesteven, S., Kern, B., D’abrusco, R., and Dorch, B.
- Subjects
Bibliometric analysis ,Observatory ,Physics ,QC1-999 ,Measure (physics) ,Bibliometrics ,Data science - Abstract
Bibliometrics are increasingly used as metrics to measure the performance of individuals, institutions and countries. Refereed publications are the primary output of modern observatories. In this paper, I use bibliometric techniques to examine the performance of astronomical observatories.
- Published
- 2018
191. Optical spectroscopic observations of gamma-ray blazar candidates. IV. results of the 2014 follow-up campaign
- Author
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Francesco Massaro, Howard A. Smith, Marco Landoni, Dan Milisavljevic, Federica Ricci, Raffaele D'Abrusco, Alessandro Paggi, N. Masetti, Daniel Stern, Gino Tosti, Ricci, Federica, Massaro, F., Landoni, M., D'Abrusco, R., Milisavljevic, D., Stern, D., Masetti, N., Paggi, A., Smith, Howard A., Tosti, G., ITA, USA, and RICCI, FEDERICA
- Subjects
Active galactic nucleus ,Radio galaxy ,radiation mechanism ,galaxies: active ,FOS: Physical sciences ,BL Lacertae objects: general , galaxies: active , radiation mechanisms: non-thermal ,active ,Astrophysics ,BL Lacertae object ,Observatory ,galaxies ,Blazar ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,galaxie ,Quasar ,Astronomy and Astrophysics ,BL Lacertae objects: general ,radiation mechanisms: non-thermal ,BL Lacertae objects ,general ,non-thermal ,radiation mechanisms ,Redshift ,Galaxy ,Space and Planetary Science ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope - Abstract
The extragalactic gamma-ray sky is dominated by the emission arising from blazars, one of the most peculiar classes of radio-loud active galaxies. Since the launch of Fermi several methods were developed to search for blazars as potential counterparts of unidentified gamma-ray sources (UGSs). To confirm the nature of the selected candidates, optical spectroscopic observations are necessary. In 2013 we started a spectroscopic campaign to investigate gamma-ray blazar candidates selected according to different procedures. The main goals of our campaign are: 1) to confirm the nature of these candidates, and 2) whenever possible determine their redshifts. Optical spectroscopic observations will also permit us to verify the robustness of the proposed associations and check for the presence of possible source class contaminants to our counterpart selection. This paper reports the results of observations carried out in 2014 in the Northern hemisphere with Kitt Peak National Observatory (KPNO) and in the Southern hemisphere with the Southern Astrophysical Research (SOAR) telescopes. We also report three sources observed with the Magellan and Palomar telescopes. Our selection of blazar-like sources that could be potential counterparts of UGSs is based on their peculiar IR colors and on their combination with radio observations both at high and low frequencies (i.e., above and below ~ 1 GHz) in publicly available large radio surveys. We present the optical spectra of 27 objects. [....] We also report the case for WISE J173052.85-035247.2, candidate counterpart of the source 2FGL J1730.6-0353, which has no radio counterpart in the major radio surveys. We confirm that our selection of gamma-ray blazars candidates can successfully indentify low-energy counterparts to Fermi unassociated sources and allow us to discover new blazars., 20 pages, 30 figures, 1 table, AJ accepted for publication (pre-proof version), Abstract cut
- Published
- 2015
192. DAMEWARE: A Web Cyberinfrastructure for Astrophysical Data Mining
- Author
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Francesco Esposito, Michelangelo Fiore, Giuseppe Longo, Mauro Garofalo, Alessandro Di Guido, Ciro Donalek, Ashish Mahabal, Alfonso Nocella, Massimo Brescia, Matthew J. Graham, Giovanni D'Angelo, Raffaele D'Abrusco, Giovanni Albano, Marisa Guglielmo, S. George Djorgovski, Stefano Cavuoti, Francesco Manna, Brescia, Massimo, Cavuoti, Stefano, Longo, Giuseppe, Nocella, Alfonso, Garofalo, Mauro, Manna, Francesco, Esposito, Francesco, Albano, Giovanni, Guglielmo, Marisa, D’Angelo, Giovanni, Di Guido, Alessandro, George Djorgovski, S., Donalek, Ciro, Mahabal, Ashish A., Graham, Matthew J., Fiore, Michelangelo, D’Abrusco, Raffaele, Brescia, M., Cavuoti, S., Longo, G., Nocella, A., Garofalo, M., Manna, F., Esposito, F., Albano, G., Guglielmo, M., D'Angelo, G., Di Guido, A., Donalek, C., Mahabal, A. A., Graham, M. J., Fiore, M., and D'Abrusco, R.
- Subjects
Computer science ,media_common.quotation_subject ,FOS: Physical sciences ,computer.software_genre ,01 natural sciences ,010104 statistics & probability ,Cyberinfrastructure ,Resource (project management) ,0103 physical sciences ,Web application ,0101 mathematics ,Cluster analysis ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,media_common ,business.industry ,Astronomy and Astrophysics ,Data analysi ,Techniques ,Variety (cybernetics) ,Identification (information) ,Space and Planetary Science ,Sky ,Data mining ,Astrophysics - Instrumentation and Methods for Astrophysics ,business ,computer - Abstract
Astronomy is undergoing through a methodological revolution triggered by an unprecedented wealth of complex and accurate data. The new panchromatic, synoptic sky surveys require advanced tools for discovering patterns and trends hidden behind data which are both complex and of high dimensionality. We present DAMEWARE (DAta Mining & Exploration Web Application REsource): a general purpose, web-based, distributed data mining environment developed for the exploration of large datasets, and finely tuned for astronomical applications. By means of graphical user interfaces, it allows the user to perform classification, regression or clustering tasks with machine learning methods. Salient features of DAMEWARE include its capability to work on large datasets with minimal human intervention, and to deal with a wide variety of real problems such as the classification of globular clusters in the galaxy NGC1399, the evaluation of photometric redshifts and, finally, the identification of candidate Active Galactic Nuclei in multiband photometric surveys. In all these applications, DAMEWARE allowed to achieve better results than those attained with more traditional methods. With the aim of providing potential users with all needed information, in this paper we briefly describe the technological background of DAMEWARE, give a short introduction to some relevant aspects of data mining, followed by a summary of some science cases and, finally, we provide a detailed description of a template use case., To appear in PASP (accepted for pubblication)
- Published
- 2014
193. Photometric classification of emission line galaxies with Machine Learning methods
- Author
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Stefano Cavuoti, Maurizio Paolillo, Raffaele D'Abrusco, Giuseppe Longo, Massimo Brescia, Cavuoti, Stefano, Brescia, Massimo, D'Abrusco, Raffaele, Longo, Giuseppe, Paolillo, Maurizio, Cavuoti, S., Brescia, M., D'Abrusco, R., Longo, G., and Paolillo, M.
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,galaxies: active ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Photometry (optics) ,Conjugate gradient method ,survey ,Emission spectrum ,Astrophysics::Galaxy Astrophysics ,Physics ,Astrophysics - Cosmology and Extragalactic Astrophysics ,business.industry ,Astronomy and Astrophysics ,Pattern recognition ,Galaxy ,galaxies: Seyfert ,Support vector machine ,Space and Planetary Science ,Multilayer perceptron ,Line (geometry) ,Artificial intelligence ,catalogue ,business ,methods: data analysi ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
In this paper we discuss an application of machine learning based methods to the identification of candidate AGN from optical survey data and to the automatic classification of AGNs in broad classes. We applied four different machine learning algorithms, namely the Multi Layer Perceptron (MLP), trained respectively with the Conjugate Gradient, Scaled Conjugate Gradient and Quasi Newton learning rules, and the Support Vector Machines (SVM), to tackle the problem of the classification of emission line galaxies in different classes, mainly AGNs vs non-AGNs, obtained using optical photometry in place of the diagnostics based on line intensity ratios which are classically used in the literature. Using the same photometric features we discuss also the behavior of the classifiers on finer AGN classification tasks, namely Seyfert I vs Seyfert II and Seyfert vs LINER. Furthermore we describe the algorithms employed, the samples of spectroscopically classified galaxies used to train the algorithms, the procedure followed to select the photometric parameters and the performances of our methods in terms of multiple statistical indicators. The results of the experiments show that the application of self adaptive data mining algorithms trained on spectroscopic data sets and applied to carefully chosen photometric parameters represents a viable alternative to the classical methods that employ time-consuming spectroscopic observations., 10 pages, 1 figure, accepted by MNRAS in October 10, 2013
- Published
- 2014
194. A web application for photometric redshift estimation
- Author
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O. LAURINO, R. D'ABRUSCO, BRESCIA M, S. CAVUOTI, A. CORAZZA, G. D'ANGELO, C. DONALEK, S. G. DJORGOVSKI, N. DENISKINA, M. FIORE, M. GAROFALO, G. LONGO, A. MAHABAL, F. MANNA, A. NOCELLA, B. SKORDOVSKI, Roberto Barbera, Marcello Iacono Manno, Marco Fargetta, Laurino, O., D'Abrusco, R., Brescia, M, Cavuoti, S., Corazza, A., D'Angelo, G., Donalek, C., Djorgovski, S. G., Deniskina, N., Fiore, M., Garofalo, M., Longo, G., Mahabal, A., Manna, F., Nocella, A., and Skordovski, B.
- Abstract
In the era of massive astronomical datasets, efficient identification of candidate quasars and the reconstruction of their three dimensional distribution in the Universe is a key requirement for constraining some of the main issues regarding the formation and evolution of QSOs. A method for the determination of photometric redshifts of QSOs based on multiwavelength photometry and on a combination of data mining techniques will be discussed. This procedure, specifically suited for accompanying the candidate selection method discussed in (D’Abrusco et al. 2008), makes use of specific tools developed under the EuroVO and NVO frameworks for data gathering, pre-processing and mining, while relying on the scaling capabilities of the computing grid. This method allowed us to obtain photometric redshifts with an increased accuracy (up to 30%) with respect to the literature.
- Published
- 2009
195. MINING THE STRUCTURE OF THE NEARBY UNIVERSE
- Author
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Massimo Brescia, E. De Filippis, Roberto Tagliaferri, Maurizio Paolillo, Giovanni Longo, Raffaele D'Abrusco, Antonino Staiano, Vito Di Gesù, Giosuè Lo Bosco, and Maria Concetta Maccarone, D'Abrusco, Raffaele, Longo, Giuseppe, Brescia, Massimo, DE FILIPPIS, Elisabetta, Paolillo, Maurizio, Staiano, Antonino, Tagliaferri, Roberto, D'Abrusco, R., Brescia, M., de Filippis, E., Staiano, A., and Tagliaferri, R.
- Subjects
Structure (mathematical logic) ,Physics ,Massive data set ,photometric redshifts ,Distributed Computing Environment ,Artificial neural network ,neural network ,media_common.quotation_subject ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Data science ,Galaxy ,Universe ,ComputingMethodologies_PATTERNRECOGNITION ,Sky ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
We discuss some preliminary results of our ongoing efforts to implement a new generation of data mining tools, largely based on neural networks and specifically tailored to work in a distributed computing environment. These tools have been applied to the Sloan Digital Sky Survey public dataset to produce a 3-D map of the galaxy distribution in the nearby universe.
- Published
- 2007
196. Steps towards a map of the nearby universe
- Author
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Massimo Brescia, Giuseppe Longo, Antonino Staiano, Raffaele D'Abrusco, E. De Filippis, Maurizio Paolillo, D'Abrusco, Raffaele, Longo, Giuseppe, A., Staiano, E., de Filippi, Paolillo, Maurizio, M., Brescia, P. Bernardini, G. Fogli and E. Lisi, D'Abrusco, R., Longo, G., Staiano, A., de Filippis, E., Paolillo, M., and Brescia, M.
- Subjects
Physics ,QSOS ,Nuclear and High Energy Physics ,Artificial neural network ,media_common.quotation_subject ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astrophysics ,Object (computer science) ,Base (topology) ,computer.software_genre ,Atomic and Molecular Physics, and Optics ,Galaxy ,Universe ,Field (computer science) ,Sky ,Data mining ,computer ,media_common - Abstract
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, in particular, to produce a list of candidate AGNs and QSOs., 3 pages, 1 figure. To appear in Nucl Phys. B, in the proceedings of the NOW-2006 (Neutrino Oscillation Workshop - 2006), R. Fogli et al. eds
- Published
- 2007
197. Steps toward a classifier for the Virtual Observatory. I. Classifying the SDSS photometric archive
- Author
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Raffaele D'Abrusco, Staiano, A., Longo, G., Paolillo, M., Filippis, E., N.Napolitano, M.Paolillo, D'Abrusco, R., Staiano, A., Longo, Giuseppe, Paolillo, Maurizio, and de Filippis, E.
- Subjects
Astrophysics (astro-ph) ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
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 complexity of the Sloan Digital Sky Survey archive, for which an example of application is reported., Comment: To appear in the Proceedings of the "1st Workshop of Astronomy and Astrophysics for Students" - Naples, 19-20 April 2006
198. The VO-Neural project:. recent developments and some applications
- Author
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Brescia, M., Cavuoti, S., D Angelo, G., Raffaele D'Abrusco, Deniskina, N., Garofalo, M., Laurino, O., Longo, G., Nocella, A., Skordovski, B., Brescia, M., Cavuoti, S., D'Angelo, G., D'Abrusco, R., Deniskina, N., Garofalo, M., Laurino, O., Longo, G., Nocella, A., and Skordovski, B.
- Subjects
Computational Engineering, Finance, and Science (cs.CE) ,FOS: Computer and information sciences ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astrophysics ,Computer Science - Computational Engineering, Finance, and Science - Abstract
VO-Neural is the natural evolution of the Astroneural project which was started in 1994 with the aim to implement a suite of neural tools for data mining in astronomical massive data sets. At a difference with its ancestor, which was implemented under Matlab, VO-Neural is written in C++, object oriented, and it is specifically tailored to work in distributed computing architectures. We discuss the current status of implementation of VO-Neural, present an application to the classification of Active Galactic Nuclei, and outline the ongoing work to improve the functionalities of the package., Contributed, Data Centre Alliance Workshops: GRID and the Virtual Observatory, April 9-11 Munich, to appear in Mem. SAIt
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