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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The circum-galactic medium of quasars: transverse and line-of-sight absorptionsQuasar 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 (QSO B) that are at the same redshift of the foreground quasar (QSO F). Here we report on optical spectroscopy, gathered at Gran Telescopio Canarias, of 14 QPPsSandrinelli, A. et al.
Advertised on:
112020 -
Optical spectroscopy of BL Lac objects: TeV candidatesWe 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), arePaiano, Simona et al.
Advertised on:
62020 -
A Second-order Moment of Microlensing Variability as a Novel Tool to Constrain Source Emission Size or Discrete Lens Demographics in Extragalactic ResearchWe 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 observationalGuerras, Eduardo et al.
Advertised on:
62020 -
Individual Estimates of the Virial Factor in 10 Quasars: Implications on the Kinematics of the Broad-line RegionAssuming 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.
Advertised on:
62020 -
Visible and near-infrared observations of interstellar comet 2I/Borisov with the 10.4-m GTC and the 3.6-m TNG telescopesIn 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, asde León, J. et al.
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42020 -
Microlensing Analysis for the Gravitational Lens Systems SDSS0924+0219, Q1355-2257, and SDSS1029+2623We 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) andRojas, K. et al.
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22020 -
Spectroscopy and polarimetry of the gravitationally lensed quasar SDSS J1004+4112 with the 6m SAO RAS telescopeContext. 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 thePopović, L. Č. et al.
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22020 -
The Initial Mass Function of Lens Galaxies from Quasar MicrolensingWe 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. TheJiménez-Vicente, J. et al.
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112019 -
Challenging a Newtonian prediction through Gaia wide binariesUnder 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 solarHernandez, X. et al.
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02019 -
Measuring Supermassive Black Hole Masses: Correlation between the Redshifts of the Fe III UV Lines and the Widths of Broad Emission LinesWe 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 estimatedMediavilla, E. et al.
Advertised on:
82019 -
A New Einstein Cross Gravitational Lens of a Lyman-break GalaxyWe 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 isBettoni, D. et al.
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32019 -
Optical Spectroscopic Survey of a Sample of Unidentified Fermi Objects: IIWe 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 thePaiano, Simona et al.
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22019 -
Estimate of the Accretion Disk Size in the Gravitationally Lensed Quasar HE 0435–1223 Using Microlensing Magnification StatisticsWe 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 theFian, C. et al.
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122018 -
New database for a sample of optically bright lensed quasars in the northern hemisphereIn the framework of the Gravitational LENses and DArk MAtter (GLENDAMA) project, we present a database of nine gravitationally lensed quasars (GLQs) that have two or four images brighter than r = 20 mag and are located in the northern hemisphere. This new database consists of a rich variety of follow-up observations included in the GLENDAMA globalGil-Merino, R. et al.
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82018 -
Systematic Redshift of the Fe III UV Lines in Quasars: Measuring Supermassive Black Hole Masses under the Gravitational Redshift HypothesisWe find that the Fe III λλ2039-2113 spectral feature in quasars appears systematically redshifted by amounts accountable under the hypothesis of gravitational redshift induced by the central supermassive black hole (BH). Our analysis of 27 composite spectra from the BOSS survey indicates that the redshift and the broadening of the lines in the FeMediavilla, E. et al.
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82018 -
High-redshift BL Lac Objects: Spectroscopy of CandidatesWe report on 16 BL Lacertae objects that were proposed to be at z > 1. We present spectroscopic observations secured at the 10.4 m GTC that allowed us to assess the redshift of these sources. In particular, for five objects, we disprove the previous value of the redshift reported in the literature and found that they lie at z 1. Moreover, two ofLandoni, M. et al.
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72018 -
Microlensing and Intrinsic Variability of the Broad Emission Lines of Lensed QuasarsWe study the broad emission lines in a sample of 11 gravitationally lensed quasars with at least two epochs of observation to identify intrinsic variability and to disentangle it from microlensing. To improve our statistical significance and emphasize trends, we also include 15 lens systems with single-epoch spectra. Mg II and C III] emission linesFian, C. et al.
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52018 -
The Redshift of the BL Lac Object TXS 0506+056The bright BL Lac object TXS 0506+056 is the most likely counterpart of the IceCube neutrino event EHE 170922A. The lack of this redshift prevents a comprehensive understanding of the modeling of the source. We present high signal-to-noise optical spectroscopy, in the range 4100–9000 Å, obtained at the 10.4 m Gran Telescopio Canarias. The spectrumPaiano, S. et al.
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22018 -
Overdensity of galaxies in the environment of quasar pairsWe report on a study of the galaxy environments of low redshift physical quasars pairs. We selected 20 pairs having projected separation 0.5 Mpc and difference of systemic velocity 800 km s-1. Using Sloan Digital Sky Survey images, we evaluated the galaxy overdensity around these quasars in pairs and then compare it with that of a sample ofSandrinelli, A. et al.
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32018 -
Optical Spectroscopic Survey of a Sample of Unidentified Fermi ObjectsWe present optical spectroscopy secured at the 10 m Gran Telescopio Canarias of the counterparts of 20 extragalactic γ-ray sources detected by the Fermi satellite. The observations allow us to investigate the nature of these sources and to determine their redshift. We find that all optical counterparts have a spectrum that is consistent with a BLPaiano, S. et al.
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122017
