Start year
1988
Organizational Unit
Organizing institutions
Grants related:
General
Description
Introduction
Gravitational lenses are a powerful tool for Astrophysics and Cosmology. The goals of this project are: i) to obtain a robust determination of the Hubble constant from the time delay measured between the images of a lensed quasar; ii) to study the individual and statistical properties of dark matter condensations in lens galaxies from microlensing on the images of lensed quasars; iii) to study the unresolved structure of quasars (broad and narrow emission line and continuum emission regions) from induced variations by microlensing in the photometry of the lensed quasar images as well as in the profile of their emission lines; iv) to study the variation of dust extinction properties with redshift from the determination of extinction curves in lens galaxies; (v) to develop new numerical and statistical methods to study microlensing and (vi) to detect exoplanets through gravitational microlensing.
Members
Principal investigator
Evencio
Mediavilla Gradolph
Project staff
Miquel
Serra Ricart
Alejandro
Oscoz Abad
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
Results
- We have introduced a new method to measure the masses of the supermassive black holes of the quasars based on the gravitational redshift of the ultraviolet lines of the iron (UV Fe III). The calculated masses are in agreement with the estimates obtained using the virial theorem.
Scientific activity
Related publications
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Black hole masses for 14 gravitationally lensed quasarsAims: 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 BinocularMelo, A. et al.
Advertised on:
122023 -
Revealing the structure of the lensed quasar Q 0957+561. III. Constraints on the size of the broad-line regionAims: 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 IIFian, C. et al.
Advertised on:
102023 -
Constraints on the Abundance of Primordial Black Holes from X-Ray Quasar Microlensing Observations: Substellar to Planetary Mass RangeWe 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 plusEsteban-Gutiérrez, A. et al.
Advertised on:
92023 -
Long-term optical spectral monitoring of a changing-look active galactic nucleus NGC 3516. II. Broad-line profile variabilityContext. 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 thePopović, Luka Č. et al.
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72023 -
The spectra of IceCube Neutrino (SIN) candidate sources - III. Optical spectroscopy and source characterization of the full sampleA 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 wePaiano, Simona et al.
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52023 -
Fast Multipole Method for Gravitational Lensing: Application to High-magnification Quasar MicrolensingWe 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 inverseJiménez-Vicente, J. et al.
Advertised on:
122022 -
Revealing the structure of the lensed quasar Q 0957+561. II. Supermassive black hole mass via gravitational redshiftAims: 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 lensedFian, C. et al.
Advertised on:
112022 -
Virial theorem in clusters of galaxies with MONDA 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.
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122022 -
A Mass Model for the Lensing Cluster SDSS J1004+4112: Constraints from the Third Time DelayWe 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 inForés-Toribio, R. et al.
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92022 -
Limiting the Abundance of LIGO/Virgo Black Holes with Microlensing Observations of Quasars of Finite SizeWe 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 toEsteban-Gutiérrez, A. et al.
Advertised on:
42022 -
On the orbital velocity of isolated galaxy pairs: II accurate MOND predictionsExamining 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 isScarpa, Riccardo et al.
Advertised on:
52022 -
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> relationContext. 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 aGarcía-Lorenzo, B. et al.
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32022 -
On the orbital velocity of isolated galaxy pairs: a test of gravity in the low acceleration regimeThe 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 theScarpa, Riccardo et al.
Advertised on:
22022 -
First black hole mass estimation for the quadruple lensed system WGD2038-4008Context. 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, whichMelo, A. et al.
Advertised on:
122021 -
Revealing the structure of the lensed quasar Q 0957+561. I. Accretion disk sizeAims: 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 toFian, C. et al.
Advertised on:
102021 -
Microlensing of the broad emission lines in 27 gravitationally lensed quasars. Broad line region structure and kinematicsAims: 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 emissionFian, C. et al.
Advertised on:
92021 -
Testing Einsteins Equivalence Principle and Its Cosmological Evolution from Quasar Gravitational RedshiftsWe 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 aMediavilla, E. et al.
Advertised on:
62021 -
The spectra of IceCube neutrino candidate sources - I. Optical spectroscopy of blazarsThere 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 TelescopioPaiano, Simona et al.
Advertised on:
72021 -
Low-redshift quasars in the SDSS Stripe 82 - II. Associated companion galaxies and signature of star formationWe 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 paperStone, M. B. et al.
Advertised on:
22021 -
The Impact of the Mass Spectrum of Lenses in Quasar Microlensing Studies. Constraints on a Mixed Population of Primordial Black Holes and StarsWe 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 ofEsteban-Gutiérrez, A. et al.
Advertised on:
122020
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