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

    • Black hole masses for 14 gravitationally lensed quasars
      Aims: We have estimated black hole masses (M BH) for 14 gravitationally lensed quasars using Balmer lines; we also provide estimates based on MgII and CIV emission lines for four and two of them, respectively. We compared these estimates to results obtained for other lensed quasars. Methods: We used spectroscopic data from the Large Binocular
      Melo, A. et al.

      Fecha de publicación:

      12
      2023
      Número de citas
      2
    • Revealing the structure of the lensed quasar Q 0957+561. III. Constraints on the size of the broad-line region
      Aims: Our aim is to examine the size, kinematics, and geometry of the broad-line region (BLR) in the double-lensed quasar Q 0957+561 by analyzing the impact of microlensing on various rest-frame ultraviolet broad-emission lines (BELs). Methods: We explore the influence of intrinsic variability and microlensing on the C IV, C III], and Mg II
      Fian, C. et al.

      Fecha de publicación:

      10
      2023
      Número de citas
      7
    • Constraints on the Abundance of Primordial Black Holes from X-Ray Quasar Microlensing Observations: Substellar to Planetary Mass Range
      We use X-ray observations of quasar microlensing (sensitive to smaller compact objects than in the optical) to study the possible presence of a population of low mass black holes (BHs; from ~10 -3 M ⊙ to 10 -1 M ⊙) in lens galaxies. We compare these observations with microlensing magnification simulations of a mixed population of stars and BHs plus
      Esteban-Gutiérrez, A. et al.

      Fecha de publicación:

      9
      2023
      Número de citas
      6
    • Long-term optical spectral monitoring of a changing-look active galactic nucleus NGC 3516. II. Broad-line profile variability
      Context. We analyze the broad Hβ line profile variability of a "changing look" active galactic nucleus (CL-AGN) NGC 3516 over an extensive period of 25 years (from 1996 to 2021). The observed change in the broad line profile may indicate a change in the geometry of the broad line region (BLR). The main objective is to follow and understand the
      Popović, Luka Č. et al.

      Fecha de publicación:

      7
      2023
      Número de citas
      7
    • The spectra of IceCube Neutrino (SIN) candidate sources - III. Optical spectroscopy and source characterization of the full sample
      A correlation between astrophysical high-energy neutrinos and blazars has been suggested by various authors. In particular, a likely association between IceCube events and intermediate- and high-energy peaked BL Lac objects has led to a sample of 47 objects having a high probability of being neutrino sources. In the first paper of this series we
      Paiano, Simona et al.

      Fecha de publicación:

      5
      2023
      Número de citas
      8
    • Fast Multipole Method for Gravitational Lensing: Application to High-magnification Quasar Microlensing
      We introduce the use of the fast multipole method (FMM) to speed up gravitational lensing ray tracing calculations. The method allows very fast calculation of ray deflections when a large number of deflectors, N *, are involved, while keeping rigorous control on the errors. In particular, we apply this method, in combination with the inverse
      Jiménez-Vicente, J. et al.

      Fecha de publicación:

      12
      2022
      Número de citas
      11
    • Revealing the structure of the lensed quasar Q 0957+561. II. Supermassive black hole mass via gravitational redshift
      Aims: We intend to use the impact of microlensing on the Fe III λλ2039−2113 emission line blend along with a measure of its gravitational redshift to estimate the mass of the quasar's central supermassive black hole (SMBH). Methods: We fit the Fe III feature in multiple spectroscopic observations between 2008 and 2016 of the gravitationally lensed
      Fian, C. et al.

      Fecha de publicación:

      11
      2022
      Número de citas
      4
    • Virial theorem in clusters of galaxies with MOND
      A specific modification of Newtonian dynamics known as MOND has been shown to reproduce the dynamics of most astrophysical systems at different scales without invoking non-baryonic dark matter (DM). There is, however, a long-standing unsolved problem when MOND is applied to rich clusters of galaxies in the form of a deficit (by a factor around two)
      López-Corredoira, M. et al.

      Fecha de publicación:

      12
      2022
      Número de citas
      4
    • A Mass Model for the Lensing Cluster SDSS J1004+4112: Constraints from the Third Time Delay
      We have built a new model for the lens system SDSS J1004+4112 including the recently measured time delay of the fourth quasar image. This time delay has a strong influence on the inner mass distribution of the lensing cluster (ρ ∝ r -α ) allowing us to determine $\alpha ={1.18}_{-0.03(-0.18)}^{+0.02(+0.11)}$ at the 68% (95%) confidence level in
      Forés-Toribio, R. et al.

      Fecha de publicación:

      9
      2022
      Número de citas
      14
    • Limiting the Abundance of LIGO/Virgo Black Holes with Microlensing Observations of Quasars of Finite Size
      We present a simple but general argument that strongly limits the abundance of primordial black holes (PBHs) (or other unknown population of compact objects) with masses similar to those determined by LIGO/Virgo from BH binary mergers. We show that quasar microlensing can be very sensitive to the mass of the lenses, and that it is able to
      Esteban-Gutiérrez, A. et al.

      Fecha de publicación:

      4
      2022
      Número de citas
      6
    • On the orbital velocity of isolated galaxy pairs: II accurate MOND predictions
      Examining a catalogue of isolated galaxy pairs, a preferred orbital intervelocity of ~ 150 km s -1 was recently reported. This discovery is difficult to reconcile with the expectations from Newtonian numerical simulations of cosmological structure formations. In a previous paper, we have shown that a preferred intervelocity for galaxy pairs is
      Scarpa, Riccardo et al.

      Fecha de publicación:

      5
      2022
      Número de citas
      4
    • HARMONI view of the host galaxies of active galactic nuclei around cosmic noon. Resolved stellar morpho-kinematics and the M<SUB>BH</SUB> − σ<SUB>⋆</SUB> relation
      Context. The formation and evolution of galaxies appear linked to the growth of supermassive black holes, as evidenced by empirical scaling relations in nearby galaxies. Understanding this co-evolution over cosmic time requires the revelation of the dynamical state of galaxies and the measurement of the mass of their central black holes (M BH) at a
      García-Lorenzo, B. et al.

      Fecha de publicación:

      3
      2022
      Número de citas
      1
    • On the orbital velocity of isolated galaxy pairs: a test of gravity in the low acceleration regime
      The dynamics of isolated galaxy pairs represents an important tool to investigate the behaviour of gravity in the low acceleration regime. Statistical analysis of a large sample of galaxy pairs led to the noticeable discovery of a region of preferred 3-dimensional velocities centered at ~150 and ~100 km s -1 wide, a feature hard to justify in the
      Scarpa, Riccardo et al.

      Fecha de publicación:

      2
      2022
      Número de citas
      4
    • First black hole mass estimation for the quadruple lensed system WGD2038-4008
      Context. The quadruple lensed system WGD2038-4008 (z s = 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
      Número de citas
      5
    • 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
      Número de citas
      11
    • 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
      Número de citas
      21
    • 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
      Número de citas
      8
    • 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
      Número de citas
      10
    • 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
      Número de citas
      2
    • 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
      Número de citas
      6

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