# Astrofísica Relativista y Teórica

Año de inicio
1988
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.

Personal del proyecto
Dr.
E. Falco
Dr.
L. Popovic
Dr.
R. Gil-Merino
Dr.
C.S. Kochanek
Dr.
V. Motta
Dr.
P. Gómez
Dr.
T. Mediavilla
Dr.
O. Ariza
Dr.
C. González-Morcillo
Dr.
J. Jiménez
Dr.
Ricardo Scarpa
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.

• 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
• 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
• 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
• 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
• 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
• 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
• 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 (MBH) at a

García-Lorenzo, B. et al.

### Fecha de publicación:

3
2022
• 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
• 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.

4
2020