Astrofísica Relativista y Teórica

Año de inicio
1988
Unidad organizativa
    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

    • First black hole mass estimation for the quadruple lensed system WGD2038-4008

      Context. The quadruple lensed system WGD2038-4008 (zs = 0.777 ± 0.001) has recently been discovered with the help of new techniques and observations. Black hole masses have been estimated for lensed quasars, but they have mostly been calculated for one broad emission line of one image. However, the images could be affected by microlensing, which

      Melo, A. et al.

      Fecha de publicación:

      12
      2021
    • Revealing the structure of the lensed quasar Q 0957+561. I. Accretion disk size

      Aims: We aim to use signatures of microlensing induced by stars in the foreground lens galaxy to infer the size of the accretion disk in the gravitationally lensed quasar Q 0957+561. The long-term photometric monitoring of this system (which so far has provided the longest available light curves of a gravitational lens system) permits us to

      Fian, C. et al.

      Fecha de publicación:

      10
      2021
    • Microlensing of the broad emission lines in 27 gravitationally lensed quasars. Broad line region structure and kinematics

      Aims: We aim to study the structure and kinematics of the broad line region (BLR) of a sample of 27 gravitationally lensed quasars with up to five different epochs of observation. This sample is composed of ∼100 spectra from the literature plus 22 unpublished spectra of 11 systems. Methods: We measure the magnitude differences in the broad emission

      Fian, C. et al.

      Fecha de publicación:

      9
      2021
    • Testing Einsteins Equivalence Principle and Its Cosmological Evolution from Quasar Gravitational Redshifts

      We propose and apply a new test of Einsteins equivalence principle (EEP) based on the gravitational redshift induced by the central supermassive black hole of quasars in the surrounding accretion disk. Specifically, we compare the observed gravitational redshift of the Fe III 2039-2113 emission line blend in quasars with the predicted values in a

      Mediavilla, E. et al.

      Fecha de publicación:

      6
      2021
    • The spectra of IceCube neutrino candidate sources - I. Optical spectroscopy of blazars

      There is mounting evidence that ultra-energetic neutrinos of astrophysical origin may be associated with blazars. Here, we investigate a unique sample of 47 blazars, ∼20 of which could be new neutrino sources. In particular, we focus on 17 objects of yet unknown redshift, for which we present optical spectroscopy secured at the Gran Telescopio

      Paiano, Simona et al.

      Fecha de publicación:

      7
      2021
    • Low-redshift quasars in the SDSS Stripe 82 - II. Associated companion galaxies and signature of star formation

      We present optical spectroscopy of the close companions of 22 low-redshift (z < 0.5) quasars (QSO) selected from a larger sample of QSO in the SDSS Stripe82 region for which both the host galaxy and the large-scale environments have been investigated in our previous work. The new observations extend the number of QSO studied in our previous paper

      Stone, M. B. et al.

      Fecha de publicación:

      2
      2021
    • The Impact of the Mass Spectrum of Lenses in Quasar Microlensing Studies. Constraints on a Mixed Population of Primordial Black Holes and Stars

      We show that quasar microlensing magnification statistics induced by a population of point microlenses distributed according to a mass spectrum can be very well approximated by that of a single-mass, monochromatic, population. When the spatial resolution (physically defined by the source size) is small compared with the Einstein radius, the mass of

      Esteban-Gutiérrez, A. et al.

      Fecha de publicación:

      12
      2020
    • 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 (QSOB) that are at the same redshift of the foreground quasar (QSOF). Here we report on optical spectroscopy, gathered at Gran Telescopio Canarias, of 14 QPPs. In

      Sandrinelli, A. et al.

      Fecha de publicación:

      11
      2020
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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

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