0000000001216303
AUTHOR
E. E. Falco
showing 15 related works from this author
MICROLENSING OF QUASAR ULTRAVIOLET IRON EMISSION
2013
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{sub s}∼4√(M/M{sub ⊙}) light-days for the Fe line-emitting regions, which is comparable to the size of the region generating the UV continuum (∼3-7 light-days). This may indicate that a significant part of the UV Fe II and Fe III emission originates in the quasar accretion disk.
THE AVERAGE SIZE AND TEMPERATURE PROFILE OF QUASAR ACCRETION DISKS
2014
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 narrow band photometry we have been able to remove contamination from the weakly microlensed broad emission lines, extinction and any uncertainties in the large-scale macro magnification of the lens model. We determine a maximum likelihood estimate for the exponent of the size versus wavelength scaling ($r_s\propto \lambda^p$ corresponding to a disk temperature profile of $T\propto r^{-1/p}$) of $p=0.75^{+0.2}_{-0.2}$, and a Bayesian estimate of $p=0.8\pm0.2$, which are significantly smaller than the prediction of thi…
Study of the Extended Narrow‐Line Region in the Host Galaxy of the Lensed QSO 2237+0305 (z= 1.69)
2004
The detection of spatially extended line emission in multiply imaged QSOs offers a new possibility to study the properties (kinematics and structure) of the ionized gas in the host galaxies of high-redshift QSOs. We have studied the arc of extended emission detected in Q2237+0305, finding that it arises from the core of the C III] λ1909 emission line and that the emission in the wings is compact. From the morphology of the emission-line profiles we have identified an additional narrow emission line component affecting the core of the spectra in the region of the arc (around component D). The kinematic analysis shows that the extended narrow-line region (NLR) exhibits broadening similar to t…
The Redshift Distribution of Flat-Spectrum Radio Sources
2003
The redshift distribution of flat-spectrum radio sources with 5 GHz flux densities S>5 mJy is a key component in using current radio lens surveys to probe the cosmological model. We have constructed the first flat-spectrum radio sample in the flux density range 3-20 mJy. Our new sample has 33 sources; we have determined the redshifts of 14 of these (42% complete). The low mean redshift, ~0.75, of our faintest sample needs to be confirmed by further observations to improve the sample completeness. We also increased the redshift completeness of several surveys of brighter flat-spectrum sources. While the mean redshift, ~1.1 of flat-spectrum samples fainter than 1 Jy is nearly constant, the fr…
Measuring Supermassive Black Hole Masses: Correlation between the Redshifts of the Fe III UV Lines and the Widths of Broad Emission Lines
2019
We test the recently proposed (Mediavilla et al. 2018) black hole mass scaling relationship based on the redshift {with respect to the quasar's rest frame} of the Fe III$\lambda\lambda$2039-2113 line blend. To this end, we fit this feature in the spectra of a well suited sample of quasars, observed with X-shooter at the Very Large Telescope (VLT), whose masses have been independently estimated using the virial theorem. For the quasars of this sample we consistently confirm the redshift of the Fe III$\lambda\lambda$2039-2113 blend and find that it correlates with the squared widths of H$\beta$, H$\alpha$ and Mg II, which are commonly used as a measure of $M_{BH}/R$ to determine masses from t…
The extinction law in high redshift galaxies
2004
We estimate the dust extinction laws in two intermediate redshift galaxies. The dust in the lens galaxy of LBQS1009-0252, which has an estimated lens redshift of zl~0.88, appears to be similar to that of the SMC with no significant feature at 2175 A. Only if the lens galaxy is at a redshift of zl~0.3, completely inconsistent with the galaxy colors, luminosity or location on the fundamental plane, can the data be fit with a normal Galactic extinction curve. The dust in the zl=0.68 lens galaxy for B0218+357, whose reddened image lies behind a molecular cloud, requires a very flat ultraviolet extinction curve with (formally) R(V)=12 +- 2. Both lens systems seem to have unusual extinction curve…
The structure of the accretion disk in the lensed quasar SBS 0909+532
2011
We derive the size and temperature profile of the accretion disk of the lensed quasar SBS 0909+532 by measuring the wavelength dependence (chromaticity) of the microlensing magnification produced by the stars in the lens galaxy. After correcting for extinction using the flux ratios of 14 emission lines, we observe a marked change in the B-A flux ratio with wavelength, varying from -0.67 ± 0.05 mag at (rest frame) ∼1460 Åto -0.24 ± 0.07 mag at ∼6560 Å. For λ ≳ 7000 both effects, extinction and microlensing, look minimal. Simulations indicate that image B rather than A is strongly microlensed. If we model the change in disk size from 1460 Å to 6560 Å using a Gaussian source (I exp(-R 2/2r 2 s…
Probing the Broad Line Region and the Accretion Disk in the Lensed Quasars HE0435-1223, WFI2033-4723, and HE2149-2745 using Gravitational Microlensing
2017
We use single-epoch spectroscopy of three gravitationally lensed quasars, HE0435-1223, WFI2033-4723, and HE2149-2745, to study their inner structure (BLR and continuum source). We detect microlensing-induced magnification in the wings of the broad emission lines of two of the systems (HE0435-1223 and WFI2033-4723). In the case of WFI2033-4723, microlensing affects two "bumps" in the spectra which are almost symmetrically arranged on the blue (coincident with an AlIII emission line) and red wings of CIII]. These match the typical double-peaked profile that follows from disk kinematics. The presence of microlensing in the wings of the emission lines indicates the existence of two different re…
The First Precise Determination of an Optical–Far‐Ultraviolet Extinction Curve Beyond the Local Group ( \documentclass{aastex} \usepackage{amsbsy} \u…
2005
We present the optical-far-ultraviolet extinction curve of the dust in the lens galaxy of the gravitational lens system SBS 0909+532 (z = 0.83). Extending our previous optical-UV estimate (from λ ~ 2 to 5 μm-1) into the far ultraviolet (from λ ~ 5 to 8 μm-1) is crucial for comparing with the extinction curves measured for Local Group galaxies in the spectral region where the differences are greatest. The SBS 0909+532 curve is similar to that of the LMC2 supershell, with a weaker 2175 A feature and a steeper rise into the UV than that observed in the Milky Way. The shapes of the extinction curve inferred from the quasar continuum and emission lines are in very good agreement. There is, howev…
Systematic Redshift of the Fe III UV Lines in Quasars. Measuring Supermassive Black Hole Masses under the Gravitational Redshift Hypothesis
2018
We find that the Fe III$\lambda\lambda$2039-2113 spectral feature in quasars appears systematically redshifted by amounts accountable under the hypothesis of gravitational redshift induced by the central supermassive black hole. Our analysis of 27 composite spectra from the BOSS survey indicates that the redshift and the broadening of the lines in the Fe III$\lambda\lambda$2039-2113 blend roughly follow the expected correlation in the weak limit of Schwarzschild geometry for virialized kinematics. Assuming that the Fe III UV redshift provides a measure of $M_{BH}\over R$ (${\Delta \lambda\over \lambda}\simeq{3\over2}{G\over c^2} {M_{BH}\over R}$) and using different estimates of the emittin…
Individual Estimates of the Virial Factor in 10 Quasars: Implications on the Kinematics of the Broad Line Region
2020
Assuming a gravitational origin for the Fe III$\lambda\lambda$2039-2113 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, $\langle f_{H\beta}\rangle={\bf 0.43\pm 0.20}$ and $\langle f_{H\alpha}\rangle={\bf 0.50\pm 0.24}$, are in good agreement with the results of previous studies for objects with lines of comparable widths. In the case of Mg II, consistent results, $f_{Mg II} \sim {\bf 0.44}$, can be also obtained accepting a reasonable scaling for the size of the emitting region. The modeling of the cumulative histograms of indi…
Microlensing and Intrinsic Variability of the Broad Emission Lines of Lensed Quasars
2018
We 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 lines are only weakly affected by microlensing, but C iv shows strong microlensing in some cases, even for regions of the line core, presumably associated with small projected velocities. However, excluding the strongly microlensed cases, there is a strikingly good match, on average, between the red wings of the C iv and C iii] profiles. Analysis of th…
Measuring Microlensing using Spectra of Multiply Lensed Quasars
2012
We report on a program of spectroscopic observations of gravitationally-lensed QSOs with multiple images. We seek to establish whether microlensing is occurring in each QSO image using only single-epoch observations. We calculate flux ratios for the cores of emission lines in image pairs to set a baseline for no microlensing. The offset of the continuum flux ratios relative to this baseline yields the microlensing magnification free from extinction, as extinction affects the continuum and the lines equally. When we find chromatic microlensing, we attempt to constrain the size of the QSO accretion disk. SDSSJ1004+4112 and HE1104-1805 show chromatic microlensing with amplitudes $0.2< |\Delta …
Microlensing of Quasar Broad Emission Lines: Constraints on Broad Line Region Size
2012
We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that high ionization lines such as CIV are more strongly microlensed than low ionization lines, indicating that the high ionization line emission regions are more compact. If we statistically model the distribution of microlensing magnifications, we obtain estimates for the broad line region radius of 24 (-15/+22) and 55 (-35/+150) light-days (90% confidence) for the high and low ionization lines, respectively. When the sample is divided attending to quasar luminosity, we find that the line emission regions of more luminous quasars are larger, with a slope c…
Constraining the neutrino emission of gravitationally lensed Flat-Spectrum Radio Quasars with ANTARES data
2014
This paper proposes to exploit gravitational lensing effects to improve the sensitivity of neutrino telescopes to the intrinsic neutrino emission of distant blazar populations. This strategy is illustrated with a search for cosmic neutrinos in the direction of four distant and gravitationally lensed Flat-Spectrum Radio Quasars. The magnification factor is estimated for each system assuming a singular isothermal profile for the lens. Based on data collected from 2007 to 2012 by the ANTARES neutrino telescope, the strongest constraint is obtained from the lensed quasar B0218+357, providing a limit on the total neutrino luminosity of this source of 1.08×10^46 erg s-1. This limit is about one o…