Astrofísica Relativista y Teórica

Año de inicio
1988
Unidad organizativa

Subvenciones relacionadas:

    General
    Descripción

    El estudio de las lentes gravitatorias proporciona poderosas herramientas en Astrofísica y Cosmología. Las principales aplicaciones de las lentes gravitatorias en las que se centra este proyecto son las siguientes: (i) estudiar la presencia de subestructura de materia obscura en las galaxias lente a partir de las anomalías en la magnificación de las imágenes múltiples de quásares (mililensing), (ii) estudiar la estructura no resuelta de los discos de acreción en los quásares (tamaño, perfil de temperaturas, perfil de luminosidad) a partir de las alteraciones inducidas por el efecto microlente en el contínuo y en las líneas de emisión, (iii) estudiar la estructura y la cinemática de la región emisora de líneas anchas en quásares a partir de la respuesta de los perfiles de las líneas de emisión anchas al efecto microlente y de la variabilidad de esta respuesta, (iv) estudiar la "dinámica del Universo" a partir de las velocidades peculiares de las galaxias lente inferidas del ritmo de variabilidad inducido por el efecto microlente y, (v) desarrollar nuevos métodos numéricos y estadísticos para estudiar el efecto microlente.

    Investigador principal
    Personal del proyecto
    1. Hemos introducido un nuevo método para medir las masas de los agujeros negros supermasivos de los quásares basado en el redshift gravitatorio de las líneas ultravioletas del hierro dos veces ionizado. Las masas calculadas están en acuerdo con las estimaciones obtenidas usando el teorema del virial.

    Publicaciones relacionadas

    • The circum-galactic medium of quasars: transverse and line-of-sight absorptions
      Quasar projected pairs (QPPs) can be used for investigating the circumgalactic medium of quasars through the study of intervening absorption lines in the spectrum of the background quasar (QSO B) that are at the same redshift of the foreground quasar (QSO F). Here we report on optical spectroscopy, gathered at Gran Telescopio Canarias, of 14 QPPs
      Sandrinelli, A. et al.

      Fecha de publicación:

      11
      2020
      Número de citas
      0
    • Optical spectroscopy of BL Lac objects: TeV candidates
      We investigate the spectroscopic optical properties of gamma-ray sources detected with high significance above 50 GeV in the Third Catalog of Hard Fermi-LAT Sources and that are good candidates as TeV emitters. We focus on the 91 sources that are labelled by the Fermi team as BL Lac (BLL) objects or blazar candidates of uncertain type (BCUs), are
      Paiano, Simona et al.

      Fecha de publicación:

      6
      2020
      Número de citas
      26
    • A Second-order Moment of Microlensing Variability as a Novel Tool to Constrain Source Emission Size or Discrete Lens Demographics in Extragalactic Research
      We define a second-order moment of the observational differential microlensing curves that can be used to impose constraints on physical properties of lensed quasars. We show that this quantity is sensitive both to variations in the source size and the deflector mass. We formulize a methodology to recover the source size from the observational
      Guerras, Eduardo et al.

      Fecha de publicación:

      6
      2020
      Número de citas
      6
    • Individual Estimates of the Virial Factor in 10 Quasars: Implications on the Kinematics of the Broad-line Region
      Assuming a gravitational origin for the Fe iiiλλ2039-2113 redshift and using microlensing based estimates of the size of the region emitting this feature, we obtain individual measurements of the virial factor, f, in 10 quasars. The average values for the Balmer lines, $\langle {f}_{{\rm{H}}\beta }\rangle =0.43\pm 0.20$ and $\langle {f}_{{\rm{H}}
      Mediavilla, E. et al.

      Fecha de publicación:

      6
      2020
      Número de citas
      10
    • Visible and near-infrared observations of interstellar comet 2I/Borisov with the 10.4-m GTC and the 3.6-m TNG telescopes
      In this work, we present the results of an observational study of 2I/Borisov carried out with the 10.4-m Gran Telescopio Canarias (GTC) and the 3.6-m Telescopio Nazionale Galileo (TNG), both telescopes located at the Roque de Los Muchachos Observatory, in the island of La Palma (Spain). The study includes images in the visible and near-infrared, as
      de León, J. et al.

      Fecha de publicación:

      4
      2020
      Número de citas
      13
    • Microlensing Analysis for the Gravitational Lens Systems SDSS0924+0219, Q1355-2257, and SDSS1029+2623
      We use spectroscopic observations of the gravitationally lensed systems SDSS0924+0219(BC), Q1355-2257(AB), and SDSS1029+2623(BC) to analyze microlensing and dust extinction in the observed components. We detect chromatic microlensing effects in the continuum and microlensing in the broad emission line profiles of the systems SDSS0924+0219(BC) and
      Rojas, K. et al.

      Fecha de publicación:

      2
      2020
      Número de citas
      14
    • Spectroscopy and polarimetry of the gravitationally lensed quasar SDSS J1004+4112 with the 6m SAO RAS telescope
      Context. We present new spectroscopic and polarimetric observations of the gravitational lens SDSS J1004+4112 taken with the 6 m telescope of the Special Astrophysical Observatory (Russia). Aims: In order to explain the variability that is observed only in the blue wing of the C IV emission line, corresponding to image A, we analyze the
      Popović, L. Č. et al.

      Fecha de publicación:

      2
      2020
      Número de citas
      17
    • The Initial Mass Function of Lens Galaxies from Quasar Microlensing
      We present a new approach to studying the initial mass function (IMF) in external galaxies based on quasar microlensing observations. We use measurements of quasar microlensing magnifications in 24 lensed quasars to estimate the average mass of the stellar population in the lens galaxies without any a priori assumption on the shape of the IMF. The
      Jiménez-Vicente, J. et al.

      Fecha de publicación:

      11
      2019
      Número de citas
      16
    • Challenging a Newtonian prediction through Gaia wide binaries
      Under Newtonian dynamics, the relative motion of the components of a binary star should follow a Keplerian scaling with separation. Once orientation effects and a distribution of ellipticities are accounted for, dynamical evolution can be modeled to include the effects of Galactic tides and stellar mass perturbers, over the lifetime of the solar
      Hernandez, X. et al.

      Fecha de publicación:

      0
      2019
      Número de citas
      34
    • Measuring Supermassive Black Hole Masses: Correlation between the Redshifts of the Fe III UV Lines and the Widths of Broad Emission Lines
      We test the recently proposed black hole mass scaling relationship based on the redshift with respect to the quasar's rest frame of the Fe III λλ2039-2113 line blend. To this end, we fit this feature in the spectra of a well suited sample of quasars, observed with X-shooter at the Very Large Telescope, whose masses have been independently estimated
      Mediavilla, E. et al.

      Fecha de publicación:

      8
      2019
      Número de citas
      13
    • A New Einstein Cross Gravitational Lens of a Lyman-break Galaxy
      We report the study of an “Einstein Cross” configuration first identified in a set of HST images by Cerny et al. Deep spectroscopic observations obtained at the Spanish 10.4 m Gran Telescopio Canarias telescope, allowed us to demonstrate the lens nature of the system, that consists of a Lyman-break galaxy (LBG), not a quasi-stellar object as is
      Bettoni, D. et al.

      Fecha de publicación:

      3
      2019
      Número de citas
      6
    • Optical Spectroscopic Survey of a Sample of Unidentified Fermi Objects: II
      We report on optical spectroscopy obtained at the 10.4 m Gran Telescopio Canarias of 28 Fermi γ-ray sources that completes the study of a sample of 60 targets of unidentified objects for which the detection of an X-ray and/or radio source inside the 3FGL error box is available. The observations aim to characterize the nature and measure the
      Paiano, Simona et al.

      Fecha de publicación:

      2
      2019
      Número de citas
      29
    • Estimate of the Accretion Disk Size in the Gravitationally Lensed Quasar HE 0435–1223 Using Microlensing Magnification Statistics
      We present a measurement of the accretion disk size of the quadruple lensed quasar HE 0435–1223 from well-sampled 13-year COSMOGRAIL optical light curves. Using accurate time delays for the images A, B, C, and D, we modeled and removed the intrinsic quasar variability, and found microlensing events of amplitude up to 0.6, 0.4, and 0.5 mag in the
      Fian, C. et al.

      Fecha de publicación:

      12
      2018
      Número de citas
      15
    • New database for a sample of optically bright lensed quasars in the northern hemisphere
      In the framework of the Gravitational LENses and DArk MAtter (GLENDAMA) project, we present a database of nine gravitationally lensed quasars (GLQs) that have two or four images brighter than r = 20 mag and are located in the northern hemisphere. This new database consists of a rich variety of follow-up observations included in the GLENDAMA global
      Gil-Merino, R. et al.

      Fecha de publicación:

      8
      2018
      Número de citas
      17
    • Systematic Redshift of the Fe III UV Lines in Quasars: Measuring Supermassive Black Hole Masses under the Gravitational Redshift Hypothesis
      We find that the Fe III λλ2039-2113 spectral feature in quasars appears systematically redshifted by amounts accountable under the hypothesis of gravitational redshift induced by the central supermassive black hole (BH). Our analysis of 27 composite spectra from the BOSS survey indicates that the redshift and the broadening of the lines in the Fe
      Mediavilla, E. et al.

      Fecha de publicación:

      8
      2018
      Número de citas
      22
    • High-redshift BL Lac Objects: Spectroscopy of Candidates
      We report on 16 BL Lacertae objects that were proposed to be at z > 1. We present spectroscopic observations secured at the 10.4 m GTC that allowed us to assess the redshift of these sources. In particular, for five objects, we disprove the previous value of the redshift reported in the literature and found that they lie at z 1. Moreover, two of
      Landoni, M. et al.

      Fecha de publicación:

      7
      2018
      Número de citas
      21
    • Microlensing and Intrinsic Variability of the Broad Emission Lines of Lensed Quasars
      We study the broad emission lines in a sample of 11 gravitationally lensed quasars with at least two epochs of observation to identify intrinsic variability and to disentangle it from microlensing. To improve our statistical significance and emphasize trends, we also include 15 lens systems with single-epoch spectra. Mg II and C III] emission lines
      Fian, C. et al.

      Fecha de publicación:

      5
      2018
      Número de citas
      33
    • The Redshift of the BL Lac Object TXS 0506+056
      The bright BL Lac object TXS 0506+056 is the most likely counterpart of the IceCube neutrino event EHE 170922A. The lack of this redshift prevents a comprehensive understanding of the modeling of the source. We present high signal-to-noise optical spectroscopy, in the range 4100–9000 Å, obtained at the 10.4 m Gran Telescopio Canarias. The spectrum
      Paiano, S. et al.

      Fecha de publicación:

      2
      2018
      Número de citas
      135
    • Overdensity of galaxies in the environment of quasar pairs
      We report on a study of the galaxy environments of low redshift physical quasars pairs. We selected 20 pairs having projected separation 0.5 Mpc and difference of systemic velocity 800 km s-1. Using Sloan Digital Sky Survey images, we evaluated the galaxy overdensity around these quasars in pairs and then compare it with that of a sample of
      Sandrinelli, A. et al.

      Fecha de publicación:

      3
      2018
      Número de citas
      5
    • Optical Spectroscopic Survey of a Sample of Unidentified Fermi Objects
      We present optical spectroscopy secured at the 10 m Gran Telescopio Canarias of the counterparts of 20 extragalactic γ-ray sources detected by the Fermi satellite. The observations allow us to investigate the nature of these sources and to determine their redshift. We find that all optical counterparts have a spectrum that is consistent with a BL
      Paiano, S. et al.

      Fecha de publicación:

      12
      2017
      Número de citas
      35

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