Persona: Díaz García, Pedro
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Díaz García
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Publicación Acceso Abierto Calibration and performance of the NIKA2 camera at the IRAM 30-m Telescope.(EDP Sciences, 2020-05-18) Perotto, L.; Ponthieu, N.; Marcías Pérez, J. F.; Adam, R.; Ade, P.; André, P.; Andrianasolo, A.; Aussel, H.; Beelen, A.; Benoit, A.; Berta, S.; Bideaud, A.; Bourrion, O.; Calvo, M.; Catalano, A.; Comis, B.; De Petris, M.; Désert, F. X.; Doyle, S.; Driessen, E. F. C.; Gómez, A.; Goupy, J.; John, D.; Kéruzoré, F.; Kramer, C.; Ladjelate, B.; Lagache, G.; Leclercq, S.; Lestrade, L. F.; Maury, A.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Navarro, Sara; Peñalver, J.; Pierfederici, F.; Pisano, G.; Revéret, V.; Ritacco, A.; Roussel, H.; Ruppin, F.; Schuster, K.; Shu, S.; Sievers, A.; Tucker, C.; Zylka, R.; Díaz García, Pedro; Romero Guzman, Catalina; Agence Nationale de la Recherche (ANR); European Commission (EC); Ministerio de Economía y Competitividad (MINECO); Centre National D'Etudes Spatiales (CNES); 0000-0001-6937-5052; 0000-0002-3101-0768; 0000-0002-5385-2763; 0000-0001-6478-7883; 0000-0001-9995-4792; 0000-0002-8752-1401; 0000-0001-7859-2139; 0000-0002-6370-2101; 0000-0001-6397-5516; 0000-0002-1371-5705; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Context. NIKA2 is a dual-band millimetre continuum camera of 2 900 kinetic inductance detectors, operating at 150 and 260 GHz, installed at the IRAM 30-m telescope in Spain. Open to the scientific community since October 2017, NIKA2 will provide key observations for the next decade to address a wide range of open questions in astrophysics and cosmology. Aims. Our aim is to present the calibration method and the performance assessment of NIKA2 after one year of observation. Methods. We used a large data set acquired between January 2017 and February 2018 including observations of primary and secondary calibrators and faint sources that span the whole range of observing elevations and atmospheric conditions encountered by the IRAM 30-m telescope. This allowed us to test the stability of the performance parameters against time evolution and observing conditions. We describe a standard calibration method, referred to as the "Baseline" method, to translate raw data into flux density measurements. This includes the determination of the detector positions in the sky, the selection of the detectors, the measurement of the beam pattern, the estimation of the atmospheric opacity, the calibration of absolute flux density scale, the flat fielding, and the photometry. We assessed the robustness of the performance results using the Baseline method against systematic effects by comparing results using alternative methods. Results. We report an instantaneous field of view of 6.5 ' in diameter, filled with an average fraction of 84%, and 90% of valid detectors at 150 and 260 GHz, respectively. The beam pattern is characterised by a FWHM of 17.6 '' +/- 0.1 '' and 11.1 '' +/- 0.2 '', and a main-beam efficiency of 47%+/- 3%, and 64%+/- 3% at 150 and 260 GHz, respectively. The point-source rms calibration uncertainties are about 3% at 150 GHz and 6% at 260 GHz. This demonstrates the accuracy of the methods that we deployed to correct for atmospheric attenuation. The absolute calibration uncertainties are of 5%, and the systematic calibration uncertainties evaluated at the IRAM 30-m reference Winter observing conditions are below 1% in both channels. The noise equivalent flux density at 150 and 260 GHz are of 9 +/- 1 mJy s(1/2) and 30 +/- 3 mJy s(1/2). This state-of-the-art performance confers NIKA2 with mapping speeds of 1388 +/- 174 and 111 +/- 11 arcmin(2) mJy(-2) h(-1) at 150 and 260 GHz. Conclusions. With these unique capabilities of fast dual-band mapping at high (better that 18 '') angular resolution, NIKA2 is providing an unprecedented view of the millimetre Universe.Publicación Acceso Abierto The miniJPAS survey: star-galaxy classification using machine learning(EDP Sciences, 2021-01-18) Baqui, P. O.; Marra, V.; Casarini, L.; Angulo, R.; Hernández Monteagudo, C.; Lopes, P. A. A.; López Sanjuan, C.; Muniesa, D. J.; Placco, V. M.; Quartin, M.; Queiroz, C.; Sobral, D.; Tempel, E.; Varela, J.; Vílchez, J. M.; Abramo, L. R.; Alcaniz, J. S.; Benítez, N.; Bonoli, S.; Carneiro, S.; Cenarro, A. J.; Cristóbal Hornillos, D.; De Amorim, A. L.; De Oliveira, C. M.; Dupke, R. A.; Ederoclite, A.; González Delgado, R. M.; Marín Franch, A.; Moles, M.; Vázquez Ramió, H.; Sodré, L.; Taylor, K.; Solano, Enrique; Díaz García, Pedro; European Commission (EC); Agencia Estatal de Investigación (AEI); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Gobierno de Aragón; Ministerio de Ciencia e Innovación (MICINN); Ministerio de Economía y Competitividad (MINECO); Ministry of Education, Culture, Sports, Science and Technology (MEXT); 0000-0002-7773-1579Context. Future astrophysical surveys such as J-PAS will produce very large datasets, the so-called “big data”, which will require the deployment of accurate and efficient machine-learning (ML) methods. In this work, we analyze the miniJPAS survey, which observed about ∼1 deg2 of the AEGIS field with 56 narrow-band filters and 4 ugri broad-band filters. The miniJPAS primary catalog contains approximately 64 000 objects in the r detection band (magAB ≲ 24), with forced-photometry in all other filters. Aims. We discuss the classification of miniJPAS sources into extended (galaxies) and point-like (e.g., stars) objects, which is a step required for the subsequent scientific analyses. We aim at developing an ML classifier that is complementary to traditional tools that are based on explicit modeling. In particular, our goal is to release a value-added catalog with our best classification. Methods. In order to train and test our classifiers, we cross-matched the miniJPAS dataset with SDSS and HSC-SSP data, whose classification is trustworthy within the intervals 15 ≤ r ≤ 20 and 18.5 ≤ r ≤ 23.5, respectively. We trained and tested six different ML algorithms on the two cross-matched catalogs: K-nearest neighbors, decision trees, random forest (RF), artificial neural networks, extremely randomized trees (ERT), and an ensemble classifier. This last is a hybrid algorithm that combines artificial neural networks and RF with the J-PAS stellar and galactic loci classifier. As input for the ML algorithms we used the magnitudes from the 60 filters together with their errors, with and without the morphological parameters. We also used the mean point spread function in the r detection band for each pointing. Results. We find that the RF and ERT algorithms perform best in all scenarios. When the full magnitude range of 15 ≤ r ≤ 23.5 is analyzed, we find an area under the curve AUC = 0.957 with RF when photometric information alone is used, and AUC = 0.986 with ERT when photometric and morphological information is used together. When morphological parameters are used, the full width at half maximum is the most important feature. When photometric information is used alone, we observe that broad bands are not necessarily more important than narrow bands, and errors (the width of the distribution) are as important as the measurements (central value of the distribution). In other words, it is apparently important to fully characterize the measurement. Conclusions. ML algorithms can compete with traditional star and galaxy classifiers; they outperform the latter at fainter magnitudes (r ≳ 21). We use our best classifiers, with and without morphology, in order to produce a value-added catalog.Publicación Acceso Abierto GASTON: Galactic Star Formation with NIKA2 – evidence for the mass growth of star-forming clumps(Oxford Academics: Oxford University Press, 2021-01-25) Rigby, A. J.; Peretto, N.; Adam, R.; Ade, P.; Anderson, M.; André, P.; Andrianasolo, A.; Aussel, H.; Bacmann, A.; Beelen, A.; Benoit, A.; Berta, S.; Bourrion, O.; Bracco, A.; Calvo, M.; Catalano, A.; De Petris, M.; Désert, F. X.; Doyle, S.; Driessen, E. F. C.; Gómez, A.; Goupy, J.; Kéruzoré, F.; Kramer, C.; Ladjelate, B.; Lagache, G.; Leclercq, S.; Lestrade, L. F.; Marcías Pérez, J. F.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Perotto, L.; Pisano, G.; Ponthieu, N.; Revéret, V.; Ristorcelli, I.; Ritacco, A.; Roussel, H.; Ruppin, F.; Schuster, K.; Shu, S.; Sievers, A.; Tucker, C.; Watkins, E. J.; Díaz García, Pedro; Romero Guzman, Catalina; Science and Technology Facilities Council (STFC); National Aeronautics and Space Administration (NASA); European Research Council (ERC); European Commission (EC); Ritacco, A. [0000-0003-0162-8206]; Rigby, A. J. [0000-0002-3351-2200]; Peretto, N. [0000-0002-6893-602X]; Bacmann, A. [0000-0003-1263-4986]Determining the mechanism by which high-mass stars are formed is essential for our understanding of the energy budget and chemical evolution of galaxies. By using the New IRAM KIDs Array 2 (NIKA2) camera on the Institut de Radio Astronomie Millimétrique (IRAM) 30-m telescope, we have conducted high-sensitivity and large-scale mapping of a fraction of the Galactic plane (GP) in order to search for signatures of the transition between the high- and low-mass star-forming modes. Here, we present the first results from the Galactic Star Formation with NIKA2 (GASTON) project, a Large Programme at the IRAM 30-m telescope that is mapping ≈2 deg2 of the inner GP, centred on ℓ = 23∘.9, b = 0∘.05, as well as targets in Taurus and Ophiuchus in 1.15- and 2.00-mm continuum wavebands. In this paper, we present the first of the GASTON GP data taken, and present initial science results. We conduct an extraction of structures from the 1.15-mm maps using a dendrogram analysis and, by comparison to the compact source catalogues from Herschel survey data, we identify a population of 321 previously undetected clumps. Approximately 80 per cent of these new clumps are 70-μm-quiet, and may be considered as starless candidates. We find that this new population of clumps are less massive and cooler, on average, than clumps that have already been identified. Further, by classifying the full sample of clumps based upon their infrared-bright fraction – an indicator of evolutionary stage – we find evidence for clump mass growth, supporting models of clump-fed high-mass star formation.Publicación Acceso Abierto Novel design of superhydrophobic and anticorrosive PTFE and PAA + β − CD composite coating deposited by electrospinning, spin coating and electrospraying techniques(Multidisciplinary Digital Publishing Institute (MDPI), 2022-10-16) Vicente, Adrián; Rivero, Pedro J.; Urdiroz, U.; Mora, J.; Palacio, J. F.; Palomares, F. J.; Rodríguez, Rafael; Díaz García, Pedro; Asociación de la Industria Navarra (AIN); Agencia Estatal de Investigación (AEI)A superhydrophobic composite coating consisting of polytetrafluoroethylene (PTFE) and poly(acrylic acid)+ β-cyclodextrin (PAA + β-CD) was prepared on an aluminum alloy AA 6061T6 substrate by a three-step process of electrospinnig, spin coating, and electrospraying. The electrospinning technique is used for the fabrication of a polymeric binder layer synthesized from PAA + β-CD. The superhydrophilic characteristic of the electrospun PAA + β-CD layer makes it suitable for the absorption of an aqueous suspension with PTFE particles in a spin-coating process, obtaining a hydrophobic behavior. Then, the electrospraying of a modified PTFE dispersion forms a layer of distributed PTFE particles, in which a strong bonding of the particles with each other and with the PTFE particles fixed in the PAA + β-CD fiber matrix results in a remarkable improvement of the particles adhesion to the substrate by different heat treatments. The experimental results corroborate the important role of obtaining hierarchical micro/nano multilevel structures for the optimization of superhydrophobic surfaces, leading to water contact angles above 170°, very low contact angle of hysteresis (CAH = 2°) and roll-off angle (αroll−off < 5°). In addition, a superior corrosion resistance is obtained, generating a barrier to retain the electrolyte infiltration. This study may provide useful insights for a wide range of applications
