Examinando por Autor "Sarro Baro, Luis Manuel"
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Publicación A Bayesian Graphical Model for Frequency Recovery of Periodic Variable Stars(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial., 2014-02-27) Delgado-Ureña Poirier, Héctor; Sarro Baro, Luis ManuelThis thesis has been developed in the context of the recently launched European Space Agency’s Gaia mission. The thesis has addressed the problem of determining the probability distributions of the real physical parameters for a variable star population, given their recovered values by the Data Processing and Analysis Consortium (DPAC) from the telemetry of the satellite. These recovered values are affected by a number of stochastic errors and systematic biases due to the aliasing phenomenon as a product of the Gaia scanning law, the optical and photometric resolution of the satellite and the algorithms used in the recovery process. The purpose of the thesis has been to model the data recovery process and infer the real distributions for the frequencies, apparent Gmagnitudes and amplitudes for a Large Magellanic Cloud (LMC) classic Cepheid star population. A two level Bayesian graphical model was constructed with the aid of a domain expert to model the recovery process and a Markov chain Monte Carlo (MCMC) algorithm specified to perform the inference. The system was implemented in the declarative BUGS language. The system was trained from a set of recovered data from an artificially generated real distribution of LMC Cepheids. The system was tested by comparing the parameters of the artificially generated real distributions with the distributions inferred by the MCMC algorithm. The results obtained have shown that the system remove successfully the systematic biases and is able to infer correctly the real frequency distribution. The results have also shown a correct inference for the real apparent magnitudes in the G band. Nevertheless, the results obtained for the case of the real amplitude distribution have not allowed to establish significant conclusions.Publicación Big Data Clustering(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial, 2017-07-07) Tizón Galisteo, Daniel; Sarro Baro, Luis ManuelEn este trabajo he realizado una investigación sobre algoritmos de clusterización que tienen órdenes de complejidad lineales o logarítmicos respecto al tiempo de ejecución, y que pueden ser paralelizables, y por tanto nos permitan trabajar con grandes cantidades de datos. Además, hay que tener en cuenta que puesto que utilizaré un cluster de Spark, los algoritmos que podremos utilizar estarán limitados por aquellos que se encuentran implementados en la librería MLlib de Apache Spark. También he llevado a cabo un estudio de distintos índices de validación interna y externa que podemos emplear para evaluar la calidad de los grupos o clusters creados por dichos algoritmos. Como caso de uso, he utilizado los datos astrométricos procedentes de millones de estrellas de nuestra galaxia proporcionados por la misión Gaia de la Agencia Espacial Europea para realizar una clusterización de dichas estrellas, con el objetivo de tratar de encontrar cúmulos estelares nuevos o recabar más información sobre los ya existentes. Para llevar a cabo el caso de estudio, dada la gran cantidad de datos a tratar, he utilizado la infraestructura facilitada por la DPAC (Data Processing and Analysis Consortium), consistente en un cluster de Apache Spark formado por 6 nodos con 16 cores y 64Gb de RAM cada uno.Publicación Computational Framework for the Assesment of New Forms of Political Organization in Social Media(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial., 2016-07-07) Aragón Asenjo, Pablo; Kaltenbrunner, Andreas; Sarro Baro, Luis ManuelSocial media has become a key mechanism for the organization of grassroots movements. In the 2015 Barcelona City Council election, Barcelona en Comú, an emerging grassroots party, was the most voted one. This candidacy was devised by activists involved in the Spanish 15M movement in order to turn citizen outrage into political change. On the one hand, the 15M movement is based on a decentralized structure. On the other hand, political science literature postulates that parties historically develop oligarchical leadership structures. This tension motivates to examine whether Barcelona en Comú preserved a decentralized structure or adopted a conventional centralized organization. This thesis proposes a computational framework to (1) better identify the Twitter networks of political parties by setting a confidence parameter in a popular community detection algorithm of the state of the art, and (2) analyze each party network by measuring the hierarchical structure, small-world phenomenon and coreness. The evaluation of the framework on the Twitter networks of the parties that ran for this election shows that the extended community detection algorithm effectively set boundaries between party networks. Although most parties consist of one single cluster, in Barcelona en Comú two well-defined groups co-exist: a cluster dominated by the party leader and the collective accounts, and another cluster formed by the movement activists. While the former group is highly centralized like traditional parties, the latter one stands out for its decentralized, cohesive and resilient structure.Publicación The cosmic DANCe of Perseus - I. Membership, phase-space structure, mass, and energy distributions(EDP Sciences, 2023-02-27) Olivares Romero, Javier; Bouy, Hervé; Miret Roig, Nuria; Galli, P. A. B.; Sarro Baro, Luis Manuel; Moraux, Estelle; Berihuete, Ángel; https://orcid.org/0000-0002-7084-487X; https://orcid.org/0000-0001-5292-0421; https://orcid.org/0000-0003-2271-9297; https://orcid.org/0000-0003-4127-7295; https://orcid.org/0000-0002-8589-4423Context. Star-forming regions are excellent benchmarks for testing and validating theories of star formation and stellar evolution. The Perseus star-forming region, being one of the youngest (< 10 Myr), closest (280−320 pc), and most studied in the literature, is a fundamental benchmark. Aims. We aim to study the membership, phase-space structure, mass, and energy (kinetic plus potential) distribution of the Perseus star-forming region using public catalogues (Gaia, APOGEE, 2MASS, and Pan-STARRS). Methods. We used Bayesian methodologies that account for extinction to identify the Perseus physical groups in the phase-space, retrieve their candidate members, derive their properties (age, mass, 3D positions, 3D velocities, and energy), and attempt to reconstruct their origin. Results. We identify 1052 candidate members in seven physical groups (one of them new) with ages between 3 and 10 Myr, dynamical super-virial states, and large fractions of energetically unbounded stars. Their mass distributions are broadly compatible with that of Chabrier for masses ≳0.1 M⊙ and do not show hints of over-abundance of low-mass stars in NGC 1333 with respect to IC 348. These groups’ ages, spatial structure, and kinematics are compatible with at least three generations of stars. Future work is still needed to clarify if the formation of the youngest was triggered by the oldest. Conclusions. The exquisite Gaia data complemented with public archives and mined with comprehensive Bayesian methodologies allow us to identify 31% more members than previous studies, discover a new physical group (Gorgophone: 7 Myr, 191 members, and 145 M⊙), and confirm that the spatial, kinematic, and energy distributions of these groups support the hierarchical star formation scenario.Publicación Diseño de un Prototipo de Sistema Experto para la generación de los Informes de Calidad relativos a los Objetos Variables detectados por la Misión Espacial GAIA(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial., 2012-09) Garcia Sedano, Fernando; Sarro Baro, Luis ManuelEl objetivo de este Trabajo Fin de Máster es el diseño de un SE diseñado para la tarea de evaluar la calidad de los muestreos o “surveys” de variabilidad obtenidos por la misión espacial GAIA. GAIA es una misión de la AGENCIA espacial Europea (ESA) con fecha prevista de lanzamiento en el año 2.013, con el objetivo de recoger datos para entender el origen y evolución de nuestra Galaxia. Esto implica la observación de unos 109 objetos celestes (el mayor y más preciso mapa galáctico realizado hasta la fecha) con posiciones, distancias y características espectrales básicas, convirtiéndose de este modo en la sucesora de la misión Hipparcos, aunque a una escala mucho mayor.Publicación Estimación de la función de luminosidad de UCDs mediante técnicas de aprendizaje automático(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial, 2021-09-01) Arroyo Galende, Borja; Sarro Baro, Luis ManuelGaia es una misión espacial cuyo objetivo es medir una muestra de estrellas de nuestra Galaxia devolviendo tanto medidas astrométricas como fotométricas. El procesamiento de datos surge entonces de forma natural para poder responder a cuestiones planteadas por el ámbito científico. En este trabajo se crea un flujo de datos que comienza con la misión Gaia (junto con observaciones de otras misiones) y termina con la construcción de un modelo jerárquico multinivel encargado de estimar las probabilidades a posteriori de distintas variables astrofísicas junto con algunos parámetros. Para ello, primero se eliminan las observaciones ruidosas mediante un bosque aleatorio entrenado sobre los conjuntos de entrenamiento positivo, o de buenas soluciones astrométricas; y negativo, o de malas soluciones astrométricas. El resultado es una lista curada de estrellas, en cuanto a que poseen una buena solución astrométrica, que se introducen como entrada al modelo jerárquico bayesiano multinivel. Dicho modelo infiere las relaciones entre las distintas variables que intervienen en el proceso y da como resultado la estimación de la secuencia principal. La función de luminosidad se representa, a priori, según una exponencial. Esta suposición, junto con la mala escalabilidad del modelo jerárquico, debido a que posee un proceso gaussiano embebido, causan la imposibilidad de realizar una inferencia completa con todas las observaciones. La excedencia con creces del tiempo teórico de dedicación a este trabajo es el mayor impedimento de cara a finalizar lo que ha sido, y es, un estudio muy completo que aborda diferentes métodos del mundo de la ciencia de datos.Publicación Estimación de la temperatura y gravedad de estrellas del archivo de COROT a partir de espectros FLAMES(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial., 2011-09) León Manzano, Gonzalo; Sarro Baro, Luis ManuelEl área de conocimiento en el que la investigación se halla enmarcada es la Minería de Datos, cuyo objetivo es el descubrimiento de patrones en grandes volúmenes de datos. El conjunto de datos del que se quiere extraer conocimiento procede de la Astronomía, en concreto, son los espectros de un conjunto de estrellas de los que se pretende estimar diversos parámetros físicos.Publicación Estudio y análisis de las técnicas del pipeline de OCA aplicadas a datos simulados de la misión GAIA(Universidad Nacional de Educación a Distancia (España). Escuela Técnica Superior de Ingeniería Informática. Departamento de Inteligencia Artificial., 2012-09-27) Pérez Liñana, Juan Gabriel; Sarro Baro, Luis Manuel; García Torres, MiguelEste Trabajo de Fin de Master se enmarca dentro de la mision GAIA de la Agencia Europea del Espacio, cuyo lanzamiento esta previsto para nales de 2013. Debido al elevado volumen de datos que se generara, se ha decidido crear un consorcio para el procesamiento y analisis de datos, llamado Gaia Data Processing and Analysis Consortium (DPAC). Dicho consorcio se encuentra dividido en 10 unidades de coordinacion de las cuales, la octava (CU8), esta enfocada en la estimacion de parametros astrofsicos a partir de las observaciones. El presente trabajo pertenece a los estudios preliminares llevados a cabo dentro del bloque de trabajo Object Clustering Algorithm (OCA) de CU8. El objetivo principal de OCA es desarrollar las herramientas adecuadas para el analisis de los datos recibidos desde la perspectiva del agrupamiento. Los principales retos de OCA son estudiar la tecnicas mas adecuadas de agrupamiento para la naturaleza de los datos de GAIA y ser capaz de escalar dichas tecnicas para poder tratar el gran volumen de datos que se recibira a lo largo de la mision. A lo largo de este trabajo se presentaran las metodologas propuestas en la literatura para poder escalar algoritmos de agrupamiento as como la descripcion de las tecnicas elegidas debido a sus propiedades.Publicación Gaia Data Release 3 Chemical cartography of the Milky Way(EDP Sciences, 2023-06-16) Recio Blanco, Alejandra; Kordopatis, G.; Laverny, P. de; Alonso Palicio, Pedro; Sarro Baro, Luis ManuelContext. The motion of stars has been used to reveal details of the complex history of the Milky Way, in constant interaction with its environment. Nevertheless, to reconstruct the Galactic history puzzle in its entirety, the chemo-physical characterisation of stars is essential. Previous Gaia data releases were supported by a smaller, heterogeneous, and spatially biased mixture of chemical data from ground-based observations. Aims. Gaia Data Release 3 opens a new era of all-sky spectral analysis of stellar populations thanks to the nearly 5.6 million stars observed by the Radial Velocity Spectrometer (RVS) and parametrised by the GSP-Spec module. In this work, we aim to demonstrate the scientific quality of Gaia’s Milky Way chemical cartography through a chemo-dynamical analysis of disc and halo populations. Methods. Stellar atmospheric parameters and chemical abundances provided by Gaia DR3 spectroscopy are combined with DR3 radial velocities and EDR3 astrometry to analyse the relationships between chemistry and Milky Way structure, stellar kinematics, and orbital parameters. Results. The all-sky Gaia chemical cartography allows a powerful and precise chemo-dynamical view of the Milky Way with unprecedented spatial coverage and statistical robustness. First, it reveals the strong vertical symmetry of the Galaxy and the flared structure of the disc. Second, the observed kinematic disturbances of the disc – seen as phase space correlations – and kinematic or orbital substructures are associated with chemical patterns that favour stars with enhanced metallicities and lower [α/Fe] abundance ratios compared to the median values in the radial distributions. This is detected both for young objects that trace the spiral arms and older populations. Several α, iron-peak elements and at least one heavy element trace the thin and thick disc properties in the solar cylinder. Third, young disc stars show a recent chemical impoverishment in several elements. Fourth, the largest chemo-dynamical sample of open clusters analysed so far shows a steepening of the radial metallicity gradient with age, which is also observed in the young field population. Finally, the Gaia chemical data have the required coverage and precision to unveil galaxy accretion debris and heated disc stars on halo orbits through their [α/Fe] ratio, and to allow the study of the chemo-dynamical properties of globular clusters. Conclusions. Gaia DR3 chemo-dynamical diagnostics open new horizons before the era of ground-based wide-field spectroscopic surveys. They unveil a complex Milky Way that is the outcome of an eventful evolution, shaping it to the present day.Publicación Gaia Data Release 3. A golden sample of astrophysical parameters(EDP Sciences, 2023-06-16) Creevey, O. L.; Lobel, A.; Pancino, Elena; Sarro Baro, Luis ManuelContext. Gaia Data Release 3 (DR3) provides a wealth of new data products for the astronomical community to exploit, including astrophysical parameters for half a billion stars. In this work, we demonstrate the high quality of these data products and illustrate their use in different astrophysical contexts. Aims. We produce homogeneous samples of stars with high-quality astrophysical parameters by exploiting Gaia DR3, while focusing on many regimes across the Hertzsprung-Russell (HR) diagram; spectral types OBA, FGKM, and ultracool dwarfs (UCDs). We also focus on specific subsamples of particular interest to the community: solar analogues, carbon stars, and the Gaia spectrophotometric standard stars (SPSS). Methods. We query the astrophysical parameter tables along with other tables in Gaia DR3 to derive the samples of the stars of interest. We validate our results using the Gaia catalogue itself and by comparison with external data. Results. We produced six homogeneous samples of stars with high-quality astrophysical parameters across the HR diagram for the community to exploit. We first focus on three samples that span a large parameter space: young massive disc stars (OBA; about 3 Million), FGKM spectral type stars (about 3 Million), and UCDs (about 20 000). We provide these sources along with additional information (either a flag or complementary parameters) as tables that are made available in the Gaia archive. We also identify 15 740 bone fide carbon stars and 5863 solar analogues, and provide the first homogeneous set of stellar parameters of the SPSS sample. We demonstrate some applications of these samples in different astrophysical contexts. We use a subset of the OBA sample to illustrate its usefulness in analysing the Milky Way rotation curve. We then use the properties of the FGKM stars to analyse known exoplanet systems. We also analyse the ages of some unseen UCD-companions to the FGKM stars. We additionally predict the colours of the Sun in various passbands (Gaia, 2MASS, WISE) using the solar-analogue sample. Conclusions. Gaia DR3 contains a wealth of new high-quality astrophysical parameters for the community to exploit.Publicación Gaia Data Release 3. Apsis. III. Non-stellar content and source classification(EDP Sciences, 2023-06-16) Delchambre, L.; Bailer Jones, C. A. L.; Bellas Velidis, I.; Drimmel, R.; Garabato, D.; Sarro Baro, Luis Manuel; https://orcid.org/0000-0003-2559-408X; https://orcid.org/0009-0004-7385-9198; https://orcid.org/0000-0002-1777-5502; https://orcid.org/0000-0002-7133-6623Context. As part of the third Gaia Data Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims. For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods. The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classifier (UGC) determine the redshifts of the sources classified as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b|> 5°. Results.Gaia DR3 includes 1591 million sources with DSC classifications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0.013 deg2 where the extinction is evaluated by TGE. Conclusions. Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0.1 for sources with empty warning flags, while UGC redshifts have a mean error of 0.008 ± 0.037 if evaluated on a clean set of spectra. An internal validation of the OA results further shows that 30 million sources are located in high confidence regions of the clustering map.Publicación Gaia Data Release 3. Exploring and mapping the diffuse interstellar band at 862 nm(EDP Sciences, 2023-06-16) Schultheis, M.; Zhao, He; Marshall, D. J.; Zhao, He; Sarro Baro, Luis ManuelContext. Diffuse interstellar bands (DIBs) are common interstellar absorption features in spectroscopic observations but their origins remain unclear. DIBs play an important role in the life cycle of the interstellar medium (ISM) and can also be used to trace Galactic structure. Aims. Here, we demonstrate the capacity of the Gaia-Radial Velocity Spectrometer (RVS) in Gaia DR3 to reveal the spatial distribution of the unknown molecular species responsible for the most prominent DIB at 862 nm in the RVS passband, exploring the Galactic ISM within a few kiloparsecs from the Sun. Methods. The DIBs are measured within the GSP-Spec module using a Gaussian profile fit for cool stars and a Gaussian process for hot stars. In addition to the equivalent widths and their uncertainties, Gaia DR3 provides their characteristic central wavelength, width, and quality flags. Results. We present an extensive sample of 476 117 individual DIB measurements obtained in a homogeneous way covering the entire sky. We compare spatial distributions of the DIB carrier with interstellar reddening and find evidence that DIB carriers are present in a local bubble around the Sun which contains nearly no dust. We characterised the DIB equivalent width with a local density of 0.19 ± 0.04 Å kpc−1 and a scale height of 98.60+11.10 −8.46 pc. The latter is smaller than the dust scale height, indicating that DIBs are more concentrated towards the Galactic plane. We determine the rest-frame wavelength with unprecedented precision (λ0 = 8620.86 ±0.019 Å in air) and reveal a remarkable correspondence between the DIB velocities and the CO gas velocities, suggesting that the 862 nm DIB carrier is related to macro-molecules. Conclusions. We demonstrate the unique capacity of Gaia to trace the spatial structure of the Galactic ISM using the 862 nm DIB.Publicación Gaia Data Release 3. External calibration of BP/RP low-resolution spectroscopic data(EDP Sciences, 2023-06-16) Montegriffo, P.; Angeli, Francesca De; Andrae, Rene; Riello, Marco; Pancino, Elena; Sarro Baro, Luis Manuel; https://orcid.org/0000-0001-5013-5948; https://orcid.org/0000-0003-1879-0488; https://orcid.org/0000-0001-8006-6365; https://orcid.org/0000-0002-3134-0935; https://orcid.org/0000-0003-0788-5879Context.Gaia Data Release 3 contains astrometry and photometry results for about 1.8 billion sources based on observations collected by the European Space Agency (ESA) Gaia satellite during the first 34 months of its operational phase (the same period covered by Gaia early Data Release 3; Gaia EDR3). Low-resolution spectra for 220 million sources are one of the important new data products included in this release. Aims. In this paper, we focus on the external calibration of low-resolution spectroscopic content, describing the input data, algorithms, data processing, and the validation of the results. Particular attention is given to the quality of the data and to a number of features that users may need to take into account to make the best use of the catalogue. Methods. We calibrated an instrument model to relate mean Gaia spectra to the corresponding spectral energy distributions (SEDs) using an extended set of calibrators: this includes modelling of the instrument dispersion relation, transmission, and line spread functions. Optimisation of the model is achieved through total least-squares regression, accounting for errors in Gaia and external spectra. Results. The resulting instrument model can be used for forward modelling of Gaia spectra or for inverse modelling of externally calibrated spectra in absolute flux units. Conclusions. The absolute calibration derived in this paper provides an essential ingredient for users of BP/RP spectra. It allows users to connect BP/RP spectra to absolute fluxes and physical wavelengths.Publicación Gaia Data Release 3. Mapping the asymmetric disc of the Milky Way(EDP Sciences, 2023-06-16) Drimmel, R.; Romero Gómez, Mercé; Chemin, L.; Ramos, Pau; Sarro Baro, Luis ManuelContext. With the most recent Gaia data release, the number of sources with complete 6D phase space information (position and velocity) has increased to well over 33 million stars, while stellar astrophysical parameters are provided for more than 470 million sources, and more than 11 million variable stars are identified. Aims. Using the astrophysical parameters and variability classifications provided in Gaia DR3, we selected various stellar populations to explore and identify non-axisymmetric features in the disc of the Milky Way in configuration and velocity space. Methods. Using more about 580 000 sources identified as hot OB stars, together with 988 known open clusters younger than 100 Myr, we mapped the spiral structure associated with star formation 4−5 kpc from the Sun. We selected over 2800 Classical Cepheids younger than 200 Myr that show spiral features extending as far as 10 kpc from the Sun in the outer disc. We also identified more than 8.7 million sources on the red giant branch (RGB), of which 5.7 million have line-of-sight velocities. This later sample allows the velocity field of the Milky Way to be mapped as far as 8 kpc from the Sun, including the inner disc. Results. The spiral structure revealed by the young populations is consistent with recent results using Gaia EDR3 astrometry and source lists based on near-infrared photometry, showing the Local (Orion) Arm to be at least 8 kpc long, and an outer arm consistent with what is seen in HI surveys, which seems to be a continuation of the Perseus arm into the third quadrant. The subset of RGB stars with velocities clearly reveals the large-scale kinematic signature of the bar in the inner disc, as well as evidence of streaming motions in the outer disc that might be associated with spiral arms or bar resonances. A local comparison of the velocity field of the OB stars reveals similarities and differences with the RGB sample. Conclusions. This cursory study of Gaia DR3 data shows there is a rich bounty of kinematic information to be explored more deeply, which will undoubtedly lead us to a clearer understanding of the dynamical nature of the non-axisymmetric structures of the Milky Way.Publicación Gaia Data Release 3. Non-stellar content and source classification(EDP Sciences, 2023-06-16) Delchambre, L.; Bailer Jones, C. A. L.; Bellas Velidis, I.; Sarro Baro, Luis ManuelContext. As part of the third Gaia Data Release, we present the contributions of the non-stellar and classifcation modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims. For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods. The Discrete Source Classier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classfication. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classfier (UGC) determine the redshifts of the sources classfied as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b| > 5◦. Results. Gaia DR3 includes 1591 million sources with DSC classications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0.013 deg2 where the extinction is evaluated by TGE. Conclusions. Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0.1 for sources with empty warning flags, while UGC redshifts have a mean error of 0.008 ± 0.037 if evaluated on a clean set of spectra. An internal validation of the OA results further shows that 30 million sources are located in high confidence regions of the clustering map.Publicación Gaia Data Release 3. Processing and validation of BP/RP low-resolution spectral data(EDP Sciences, 2023-06-16) Angeli, Francesca De; Weiler, Michael; Montegriffo, P.; Evans, Dafydd Wyn; Sarro Baro, Luis Manuel; https://orcid.org/0000-0003-1879-0488; https://orcid.org/0000-0002-3007-3927; https://orcid.org/0000-0001-5013-5948; https://orcid.org/0000-0002-6685-5998Context. Blue (BP) and Red (RP) Photometer low-resolution spectral data are one of the exciting new products in Gaia Data Release 3 (Gaia DR3). These data have also been used to derive astrometry and integrated photometry in Gaia Early Data Release 3 and astrophysical parameters and Solar System object reflectance spectra in Gaia DR3. Aims. In this paper, we give an overview of the processing techniques that allow raw satellite data of multiple transits per source to be converted into combined spectra calibrated to an internal reference system, resulting in low-resolution BP and RP mean spectra. We describe how we overcome challenges due to the complexity of the on-board instruments and to the various observation strategies. Furthermore, we show highlights from our scientific validation of the results. This work covers the internal calibration of BP/RP spectra to a self-consistent mean instrument, while the calibration of the BP/RP spectra to the absolute reference system of physical flux and wavelength is covered by one of the accompanying Gaia DR3 papers. Methods. We calibrate about 65 billion individual transit spectra onto the same mean BP/RP instrument through a series of calibration steps, including background subtraction, calibration of the CCD geometry, and an iterative procedure for the calibration of CCD efficiency as well as variations of the line-spread function and dispersion across the focal plane and in time. The calibrated transit spectra are then combined for each source in terms of an expansion into continuous basis functions. We discuss the configuration of these basis functions. Results. Time-averaged mean spectra covering the optical to near-infrared wavelength range [330, 1050] nm are published for approximately 220 million objects. Most of these are brighter than G = 17.65 but some BP/RP spectra are published for sources down to G = 21.43. Their signal-to-noise ratio (S/N) varies significantly over the wavelength range covered, and with magnitude and colour of the observed objects, with sources around G = 15 having a S/N above 100 in some wavelength ranges. The top-quality BP/RP spectra are achieved for sources with magnitudes 9 < G < 12, with S/N reaching 1000 in the central part of the RP wavelength range. Scientific validation suggests that the internal calibration was generally successful. However, there is some evidence for imperfect calibrations at the bright end G < 11, where calibrated BP/RP spectra can exhibit systematic flux variations that exceed their estimated flux uncertainties. We also report that, due to long-range noise correlations, BP/RP spectra can exhibit wiggles when sampled in pseudo-wavelength. Conclusions. The Gaia DR3 data products are the expansion coefficients and corresponding covariance matrices for BP and RP separately. Users are encouraged to work with the data in this format, with full covariance information showing that correlations between coefficients are typically very low. Documentation and instructions on how to access and use BP/RP spectral data from the archive are also provided.Publicación Gaia Data Release 3. Pulsations in main sequence OBAF-type stars(EDP Sciences, 2023-06-16) Ridder, Joris De; Ripepi, Vincenzo; Aerts, C.; Palaversa, Lovro; Sarro Baro, Luis ManuelContext. The third Gaia data release provides photometric time series covering 34 months for about 10 million stars. For many of those stars, a characterisation in Fourier space and their variability classification are also provided. This paper focuses on intermediate- to high-mass (IHM) main sequence pulsators (M ≥ 1.3 M) of spectral types O, B, A, or F, known as βCep, slowly pulsating B (SPB), δ Sct, and γ Dor stars. These stars are often multi-periodic and display low amplitudes, making them challenging targets to analyse with sparse time series. Aims. We investigate the extent to which the sparse Gaia DR3 data can be used to detect OBAF-type pulsators and discriminate them from other types of variables. We aim to probe the empirical instability strips and compare them with theoretical predictions. The most populated variability class is that of the δ Sct variables. For these stars, we aim to confirm their empirical period-luminosity (PL) relation, and verify the relation between their oscillation amplitude and rotation. Methods. All datasets used in this analysis are part of the Gaia DR3 data release. The photometric time series were used to perform a Fourier analysis, while the global astrophysical parameters necessary for the empirical instability strips were taken from the Gaia DR3 gspphot tables, and the v sin i data were taken from the Gaia DR3 esphs tables. The δ Sct PL relation was derived using the same photometric parallax method as the one recently used to establish the PL relation for classical Cepheids using Gaia data. Results. We show that for nearby OBAF-type pulsators, the Gaia DR3 data are precise and accurate enough to pinpoint them in the Hertzsprung Russell (HR) diagram. We find empirical instability strips covering roader regions than theoretically predicted. In particular, our study reveals the presence of fast rotating gravity-mode pulsators outside the strips, as well as the co-existence of rotationally modulated variables inside the strips as reported before in the literature. We derive an extensive period–luminosity relation for δ Sct stars and provide evidence that the relation features different regimes depending on the oscillation period. We demonstrate how stellar rotation attenuates the amplitude of the dominant oscillation mode of δ Sct stars. Conclusions. The Gaia DR3 time-series photometry already allows for the detection of the dominant (non-)radial oscillation mode in about 100 000 intermediate- and high-mass dwarfs across the entire sky. This detection capability will increase as the time series becomes longer, allowing the additional delivery of frequencies and amplitudes of secondary pulsation modes.Publicación Gaia Data Release 3. Reflectance spectra of Solar System small bodies(EDP Sciences, 2023-06-16) Galluccio, Laurent; Delbo, M.; Ángeli, F. De; Sarro Baro, Luis Manuel::virtual::2673::600; Sarro Baro, Luis Manuel; Sarro Baro, Luis Manuel; Sarro Baro, Luis ManuelContext. The Gaia mission of the European Space Agency (ESA) has been routinely observing Solar System objects (SSOs) since the beginning of its operations in August 2014. The Gaia data release three (DR3) includes, for the first time, the mean reflectance spectra of a selected sample of 60 518 SSOs, primarily asteroids, observed between August 5, 2014, and May 28, 2017. Each reflectance spectrum was derived from measurements obtained by means of the Blue and Red photometers (BP/RP), which were binned in 16 discrete wavelength bands. For every spectrum, the DR3 also contains additional information about the data quality for each band. Aims. We describe the processing of the Gaia spectral data of SSOs, explaining both the criteria used to select the subset of asteroid spectra published in Gaia DR3, and the different steps of our internal validation procedures. In order to further assess the quality of Gaia SSO reflectance spectra, we carried out external validation against SSO reflectance spectra obtained from ground-based and space-borne telescopes and available in the literature; we present our validation approach. Methods. For each selected SSO, an epoch reflectance was computed by dividing the calibrated spectrum observed by the BP/RP at each transit on the focal plane by the mean spectrum of a solar analogue. The latter was obtained by averaging the Gaia spectral measurements of a selected sample of stars known to have very similar spectra to that of the Sun. Finally, a mean of the epoch reflectance spectra was calculated in 16 spectral bands for each SSO. Results. Gaia SSO reflectance spectra are in general agreement with those obtained from a ground-based spectroscopic campaign specifically designed to cover the same spectral interval as Gaia and mimic the illumination and observing geometry characterising Gaia SSO observations. In addition, the agreement between Gaia mean reflectance spectra and those available in the literature is good for bright SSOs, regardless of their taxonomic spectral class. We identify an increase in the spectral slope of S-type SSOs with increasing phase angle. Moreover, we show that the spectral slope increases and the depth of the 1 um absorption band decreases for increasing ages of S-type asteroid families. The latter can be interpreted as proof of progressive ageing of S-type asteroid surfaces due to their exposure to space weathering eects.Publicación Gaia Data Release 3. Stellar multiplicity, a teaser for the hidden treasure(EDP Sciences, 2023-06-16) Arenou, F.; Babusiaux, C.; Barstow, M. A.; Sarro Baro, Luis ManuelContext. The Gaia DR3 catalogue contains, for the first time, about 800 000 solutions with either orbital elements or trend parameters for astrometric, spectroscopic, and eclipsing binaries, and combinations of these three. Aims. With this paper, we aim to illustrate the huge potential of this large non-single-star catalogue. Methods. Using the orbital solutions and models of the binaries, we have built a catalogue of tens of thousands of stellar masses or lower limits thereof, some with consistent flux ratios. Properties concerning the completeness of the binary catalogues are discussed, statistical features of the orbital elements are explained, and a comparison with other catalogues is performed. Results. Illustrative applications are proposed for binaries across the Hertzsprung-Russell Diagram (HRD). Binarity is studied in the giant branch and a search for genuine spectroscopic binaries among long-period variables is performed. The discovery of new EL CVn systems illustrates the potential of combining variability and binarity catalogues. Potential compact object companions are presented, mainly white dwarf companions or double degenerates, but one candidate neutron star is also found. Towards the bottom of the main sequence, the orbits of previously suspected binary ultracool dwarfs are determined and new candidate binaries are discovered. The long awaited contribution of Gaia to the analysis of the substellar regime shows the brown dwarf desert around solar-type stars using true rather than minimum masses, and provides new important constraints on the occurrence rates of substellar companions to M dwarfs. Several dozen new exoplanets are proposed, including two with validated orbital solutions and one super-Jupiter orbiting a white dwarf, all being candidates requiring confirmation. Besides binarity, higher order multiple systems are also found. Conclusions. By increasing the number of known binary orbits by more than one order of magnitude, Gaia DR3 will provide a rich reservoir of dynamical masses and an important contribution to the analysis of stellar multiplicity.Publicación Gaia Data Release 3. Summary of the content and survey properties(EDP Sciences, 2023-06-16) Vallenari, Antonella; Brown, Anthony; Prusti, Timo; Bruijne, Jos de; Sarro Baro, Luis Manuel::virtual::6209::600; Sarro Baro, Luis Manuel; Sarro Baro, Luis Manuel; Sarro Baro, Luis Manuel; https://orcid.org/0000-0003-0014-519X; https://orcid.org/0000-0002-7419-9679; https://orcid.org/0000-0003-3120-7867; https://orcid.org/0000-0001-6459-8599Context. We present the third data release of the European Space Agency’s Gaia mission, Gaia DR3. This release includes a large variety of new data products, notably a much expanded radial velocity survey and a very extensive astrophysical characterisation of Gaia sources. Aims. We outline the content and the properties of Gaia DR3, providing an overview of the main improvements in the data processing in comparison with previous data releases (where applicable) and a brief discussion of the limitations of the data in this release. Methods. The Gaia DR3 catalogue is the outcome of the processing of raw data collected with the Gaia instruments during the first 34 months of the mission by the Gaia Data Processing and Analysis Consortium. Results. The Gaia DR3 catalogue contains the same source list, celestial positions, proper motions, parallaxes, and broad band photometry in the G, GBP, and GRP pass-bands already present in the Early Third Data Release, Gaia EDR3. Gaia DR3 introduces an impressive wealth of new data products. More than 33 million objects in the ranges GRVS < 14 and 3100 < Teff < 14 500, have new determinations of their mean radial velocities based on data collected by Gaia. We provide GRVS magnitudes for most sources with radial velocities, and a line broadening parameter is listed for a subset of these. Mean Gaia spectra are made available to the community. The Gaia DR3 catalogue includes about 1 million mean spectra from the radial velocity spectrometer, and about 220 million low-resolution blue and red prism photometer BP/RP mean spectra. The results of the analysis of epoch photometry are provided for some 10 million sources across 24 variability types. Gaia DR3 includes astrophysical parameters and source class probabilities for about 470 million and 1500 million sources, respectively, including stars, galaxies, and quasars. Orbital elements and trend parameters are provided for some 800 000 astrometric, spectroscopic and eclipsing binaries. More than 150 000 Solar System objects, including new discoveries, with preliminary orbital solutions and individual epoch observations are part of this release. Reflectance spectra derived from the epoch BP/RP spectral data are published for about 60 000 asteroids. Finally, an additional data set is provided, namely the Gaia Andromeda Photometric Survey, consisting of the photometric time series for all sources located in a 5.5 degree radius field centred on the Andromeda galaxy. Conclusions. This data release represents a major advance with respect to Gaia DR2 and Gaia EDR3 because of the unprecedented quantity, quality, and variety of source astrophysical data. To date this is the largest collection of all-sky spectrophotometry, radial velocities, variables, and astrophysical parameters derived from both low- and high-resolution spectra and includes a spectrophotometric and dynamical survey of SSOs of the highest accuracy. The non-single star content surpasses the existing data by orders of magnitude. The quasar host and galaxy light profile collection is the first such survey that is all sky and space based. The astrophysical information provided in Gaia DR3 will unleash the full potential of Gaia’s exquisite astrometric, photometric, and radial velocity surveys.