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

    • Spectroscopy of 10 γ-Ray BL Lac Objects at High Redshift

      We present optical spectra with high signal-to-noise ratio of 10 BL Lac objects detected at GeV energies by the Fermi satellite (3FGL catalog), which previous observations suggested are at relatively high redshift. The new observations, obtained at the 10 m Gran Telescopio Canarias, allowed us to find the redshift for J0814.5+2943 (z = 0.703), and

      Paiano, S. et al.

      Fecha de publicación:

      8
      2017
      Número de citas
      30
    • On the lensed blazar B0218+357

      We present an optical spectrum (λλ4000-10 500) of the lensed blazar B0218+357 secured at the 10 m GTC and aimed to investigate and clarify the properties of this intriguing system. We found that the emission line spectrum of the blazar is characterized by only one broad emission line that interpreted as Mg ii 2800 Å yields z = 0.95. In addition, we

      Falomo, R. et al.

      Fecha de publicación:

      9
      2017
      Número de citas
      8
    • On the Redshift of TeV BL Lac Objects

      We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a sample of 22 BL Lac objects detected (or candidates) at TeV energies, aiming to determine or constrain their redshift. This is of fundamental importance for the interpretation of their emission models and for population studies and is also mandatory

      Paiano, S. et al.

      Fecha de publicación:

      3
      2017
      Número de citas
      70
    • Limits on the Mass and Abundance of Primordial Black Holes from Quasar Gravitational Microlensing

      The idea that dark matter can be made of intermediate-mass primordial black holes (PBHs) in the 10 M ⊙ ≲ M ≲ 200 M ⊙ range has recently been reconsidered, particularly in the light of the detection of gravitational waves by the LIGO experiment. The existence of even a small fraction of dark matter in black holes should nevertheless result in

      Mediavilla, E. et al.

      Fecha de publicación:

      2
      2017
      Número de citas
      72
    • Probing the Broad-line Region and the Accretion Disk in the Lensed Quasars HE 0435-1223, WFI 2033-4723, and HE 2149-2745 Using Gravitational Microlensing

      We use single-epoch spectroscopy of three gravitationally lensed quasars, HE 0435-1223, WFI 2033-4723, and HE 2149-2745, to study their inner structure (broad-line region [BLR] and continuum source). We detect microlensing-induced magnification in the wings of the broad emission lines of two of the systems (HE 0435-1223 and WFI 2033-4723). In the

      Motta, V. et al.

      Fecha de publicación:

      2
      2017
      Número de citas
      31
    • MONDian dynamical modelling of NGC 288 with β ≠ 0

      NGC 288 is a diffuse Galactic globular cluster; it is remarkable in that its low density results in internal accelerations being below the critical MOND a0 acceleration throughout. This makes it an ideal testing ground for MONDian gravity, as the details of the largely unknown transition function between the Newtonian and modified regimes become

      Hernandez, X. et al.

      Fecha de publicación:

      1
      2017
      Número de citas
      9
    • What Is the Redshift of the Gamma-ray BL Lac Source S4 0954+65?

      High signal-to-noise ratio spectroscopic observations of the BL Lac object S4 0954+65 at the alleged redshift z = 0.367 are presented. This source was detected at gamma frequencies by the MAGIC (TeV) and FERMI (GeV) telescopes during a remarkable outburst that occurred in 2015 February, making the determination of its distance particularly relevant

      Landoni, M. et al.

      Fecha de publicación:

      12
      2015
      Número de citas
      27
    • Resolving the Innermost Region of the Accretion Disk of the Lensed Quasar Q2237+0305 through Gravitational Microlensing

      We study three high magnification microlensing events, generally recognized as probable caustic crossings, in the optical light curves of the multiply imaged quasar Q2237+0305. We model the light curve of each event as the convolution of a standard thin disk luminosity profile with a straight fold caustic. We also allow for a linear gradient that

      Mediavilla, E. et al.

      Fecha de publicación:

      12
      2015
      Número de citas
      13
    • Probing the Dark Matter Radial Profile in Lens Galaxies and the Size of X-Ray Emitting Region in Quasars with Microlensing

      We use X-ray and optical microlensing measurements to study the shape of the dark matter density profile in the lens galaxies and the size of the (soft) X-ray emission region. We show that single epoch X-ray microlensing is sensitive to the source size. Our results, in good agreement with previous estimates, show that the size of the X-ray emission

      Jiménez-Vicente, J. et al.

      Fecha de publicación:

      6
      2015
      Número de citas
      33
    • Dark Matter Mass Fraction in Lens Galaxies: New Estimates from Microlensing

      We present a joint estimate of the stellar/dark matter mass fraction in lens galaxies and the average size of the accretion disk of lensed quasars based on microlensing measurements of 27 quasar image pairs seen through 19 lens galaxies. The Bayesian estimate for the fraction of the surface mass density in the form of stars is α = 0.21 ± 0.14 near

      Jiménez-Vicente, J. et al.

      Fecha de publicación:

      2
      2015
      Número de citas
      48
    • Statistics of Microlensing Caustic Crossings in Q 2237+0305: Peculiar Velocity of the Lens Galaxy and Accretion Disk Size

      We use the statistics of caustic crossings induced by microlensing in the lens system Q 2237+0305 to study the lens galaxy peculiar velocity. We calculate the caustic crossing rates for a comprehensive family of stellar mass functions and find a dependence of the average number of caustic crossings with the effective transverse velocity and the

      Mediavilla, E. et al.

      Fecha de publicación:

      1
      2015
      Número de citas
      16
    • Strong Chromatic Microlensing in HE0047–1756 and SDSS1155+6346

      We use spectra of the double-lensed quasars HE0047–1756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Lyα line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the

      Rojas, K. et al.

      Fecha de publicación:

      12
      2014
      Número de citas
      23
    • UV surface brightness of galaxies from the local universe to z ~ 5

      The Tolman test for surface brightness (SB) dimming was originally proposed as a test for the expansion of the universe. The test, which is independent of the details of the assumed cosmology, is based on comparisons of the SB of identical objects at different cosmological distances. Claims have been made that the Tolman test provides compelling

      Lerner, E. J. et al.

      Fecha de publicación:

      5
      2014
      Número de citas
      13
    • The extent of the Mg II absorbing circumgalactic medium of quasars

      We investigate the extent and the properties of the Mg II cool, low-density absorbing gas located in the halo and in the circumgalactic environment of quasars, using a sample of 31 projected quasar pairs with impact parameter pd < 200 kpc in the redshift range 0.5 ≲ z ≲ 1.6. In the transverse direction, we detect 18 Mg II absorbers associated with

      Farina, E. P. et al.

      Fecha de publicación:

      6
      2014
      Número de citas
      34
    • Photometric Decomposition of Mergers in Disk Galaxies

      Several observational studies and numerical simulations suggest that mergers must contribute to the evolution of galaxies; however, the role that they play is not yet fully understood. In this paper we study a sample of 52 double nucleus disk galaxies that are considered as candidates for a minor merger event. The luminosity of each of the nuclei

      Mezcua, M. et al.

      Fecha de publicación:

      3
      2014
      Número de citas
      23
    • The Average Size and Temperature Profile of Quasar Accretion Disks

      We use multi-wavelength microlensing measurements of a sample of 10 image pairs from 8 lensed quasars to study the structure of their accretion disks. By using spectroscopy or narrowband photometry, we have been able to remove contamination from the weakly microlensed broad emission lines, extinction, and any uncertainties in the large-scale macro

      Mediavilla, E. et al.

      Fecha de publicación:

      3
      2014
      Número de citas
      61
    • Long-term Monitoring, Time Delay, and Microlensing in the Gravitational Lens System Q0142-100

      We present 12 yr of monitoring of the gravitational lens Q0142-100 from the Teide Observatory. The data, taken from 1999 to 2010, comprise 105 observing nights with the IAC80 Telescope. The application of the δ2 method to the dataset leads to a value for the time delay between both components of the system of 72 ± 22 days (68% confidence level)

      Muñoz, J. A. et al.

      Fecha de publicación:

      12
      2013
      Número de citas
      7
    • Microlensing of Quasar Ultraviolet Iron Emission

      We measure the differential microlensing of the UV Fe II and Fe III emission line blends between 14 quasar image pairs in 13 gravitational lenses. We find that the UV iron emission is strongly microlensed in four cases with amplitudes comparable to that of the continuum. Statistically modeling the magnifications, we infer a typical size of r_s\sim

      Guerras, E. et al.

      Fecha de publicación:

      12
      2013
      Número de citas
      18
    • Reclassification of the nearest quasar pair candidate: SDSS J15244+3032-RXS J15244+3032

      We present optical spectroscopy of the nearest quasar pair listed in the 13th edition of the Véron-Cetty & Véron catalogue, i.e. the two quasars SDSS J15244+3032 and RXS J15244+3032 (redshift z≈0.27, angular separation Δ θ≈7″, and line-of-sight velocity difference ΔV≈1900 km/s). This system would be an optimal candidate to investigate the mutual

      Farina, E. P. et al.

      Fecha de publicación:

      5
      2013
      Número de citas
      0
    • Microlensing of Quasar Broad Emission Lines: Constraints on Broad Line Region Size

      We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that the broad emission lines are in general weakly microlensed. The results show, at a modest level of confidence (1.8σ), that high ionization lines such as C IV are more strongly microlensed than low ionization

      Falco, E. et al.

      Fecha de publicación:

      2
      2013
      Número de citas
      68

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