References of "Sluse, Dominique"
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See detailUsing strong lensing to understand the microJy radio emission in two radio quiet quasars at redshift 1.7
Hartley, P.; Jackson, N.; Badole, S. et al

in Monthly Notices of the Royal Astronomical Society (2021), 508

The radio quasar luminosity function exhibits an upturn around $L_{6\rm \:GHz}=10^{23}$ W Hz[SUP]-1[/SUP] that is well-modelled by a star-forming host galaxy population. This distribution leads some ... [more ▼]

The radio quasar luminosity function exhibits an upturn around $L_{6\rm \:GHz}=10^{23}$ W Hz[SUP]-1[/SUP] that is well-modelled by a star-forming host galaxy population. This distribution leads some authors to cite star formation as the main radio emission mechanism in so-called radio-quiet quasars (RQQs). Understanding the origin of RQQ radio emission is crucial for our understanding of quasar feedback mechanisms - responsible for the regulation of star formation in the host galaxy - and for understanding galaxy evolution as a whole. By observing RQQs that have been magnified by strong gravitational lensing, we have direct access to the RQQ population out to cosmic noon, where evidence for twin mini-jets has recently been found in a sub-$\mu$Jy RQQ. Here we present radio observations of two lensed RQQs using the VLA at 5 GHz, the latest objects to be observed in a sample of quadruply-imaged RQQs above -30°. In SDSS J1004+4112 we find strong evidence for AGN-related radio emission in the variability of the source. In PG 1115+080 we find tentative evidence for AGN-related emission, determined by comparing the radio luminosity with modelled dust components. If confirmed in the case of PG 1115+080, which lies on the radio-FIR correlation, the result would reinforce the need for caution when applying the correlation to rule out jet activity and when assuming no AGN heating of FIR-emitting dust when calculating star formation rates. Our programme so far has shown that the two of the faintest radio sources ever imaged show strong evidence for AGN-dominated radio emission. [less ▲]

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See detailGeometry and kinematics of the broad emission line region in the lensed quasar Q2237+0305
Hutsemekers, Damien ULiege; Sluse, Dominique ULiege

in Astronomy and Astrophysics (2021), 654

Line profile distortions are commonly observed in gravitationally lensed quasar spectra. These distortions are caused by microlensing from the stars in the lensing galaxy, which produce differential ... [more ▼]

Line profile distortions are commonly observed in gravitationally lensed quasar spectra. These distortions are caused by microlensing from the stars in the lensing galaxy, which produce differential magnification of spatially and kinematically separated parts of the broad line region (BLR). The quasi-simultaneous visible and near-infrared spectroscopy of the lensed quasar Q2237+0305 reveals strong microlensing-induced line deformations in the high-ionization C IVλ1549 Å and the low-ionization Hα emission lines. We use this effect to constrain the BLR size, geometry, and kinematics in Q2237+0305. For this purpose, we modeled the deformation of the emission lines for three representative BLR models: a Keplerian disk, an equatorial wind, and a biconical polar wind. We considered various inclinations with respect to the line of sight. We find that the observed microlensing effect, characterized by a set of four indices, can only be reproduced by a subsample of the considered BLR models. The microlensing analysis favors a Keplerian disk model for the regions emitting the C IV and the Hα emission lines. A polar wind model remains possible for the C IV BLR, although it is less likely. The equatorial wind model is totally excluded. A preferred inclination of the BLR of 40° is found, in agreement with expectations for a type 1 AGN and past constraints on the accretion disk inclination. The half-light radius of the BLR is r[SUB]1/2[/SUB] ≃ 47 ± 19 light-days, with no significant difference between the C IV and Hα BLRs. The size of the C IV BLR agrees with the radius-luminosity relation derived from reverberation mapping, while the size of the Balmer line BLR is one order of magnitude smaller, possibly revealing different quasar properties at high luminosities and high accretion rates. [less ▲]

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See detailErratum: VLA and ALMA observations of the lensed radio-quiet quasar SDSS J0924+0219: a molecular structure in a 3 µJy radio source
Badole, Shruti; Jackson, Neal; Hartley, Philippa et al

in Monthly Notices of the Royal Astronomical Society (2021), 507

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See detailHOLISMOKES. V. Microlensing of type II supernovae and time-delay inference through spectroscopic phase retrieval
Bayer, J.; Huber, S.; Vogl, C. et al

in Astronomy and Astrophysics (2021), 653

We investigate strongly gravitationally lensed type II supernovae (LSNe II) for time-delay cosmography, incorporating microlensing effects; this expands on previous microlensing studies of type Ia ... [more ▼]

We investigate strongly gravitationally lensed type II supernovae (LSNe II) for time-delay cosmography, incorporating microlensing effects; this expands on previous microlensing studies of type Ia supernovae (SNe Ia). We use the radiative-transfer code TARDIS to recreate five spectra of the prototypical SN 1999em at different times within the plateau phase of the light curve. The microlensing-induced deformations of the spectra and light curves are calculated by placing the SN into magnification maps generated with the code GERLUMPH. We study the impact of microlensing on the color curves and find that there is no strong influence on them during the investigated time interval of the plateau phase. The color curves are only weakly affected by microlensing due to the almost achromatic behavior of the intensity profiles. However, the lack of nonlinear structure in the color curves during the plateau phase of type II-plateau supernovae makes time-delay measurements more challenging compared to SN Ia color curves, given the possible presence of differential dust extinction. Therefore, we further investigate SN phase inference through spectral absorption lines under the influence of microlensing and Gaussian noise. As the spectral features shift to longer wavelengths with progressing time after explosion, the measured wavelength of a specific absorption line provides information on the epoch of the SN. The comparison between retrieved epochs of two observed lensing images then gives the time delay of the images. We find that the phase retrieval method that uses spectral features yields accurate delays with uncertainties of ≲2 days, making it a promising approach. [less ▲]

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See detaillenstronomy II: A gravitational lensing softwareecosystem
Birrer, Simon; Shajib, Anowar J.; Gilman, Daniel et al

in Journal of Open Source Software (2021)

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See detailTime delay lens modelling challenge
Ding, X.; Treu, T.; Birrer, S. et al

in Monthly Notices of the Royal Astronomical Society (2021), 503

In recent years, breakthroughs in methods and data have enabled gravitational time delays to emerge as a very powerful tool to measure the Hubble constant H[SUB]0[/SUB]. However, published state-of-the ... [more ▼]

In recent years, breakthroughs in methods and data have enabled gravitational time delays to emerge as a very powerful tool to measure the Hubble constant H[SUB]0[/SUB]. However, published state-of-the-art analyses require of order 1 yr of expert investigator time and up to a million hours of computing time per system. Furthermore, as precision improves, it is crucial to identify and mitigate systematic uncertainties. With this time delay lens modelling challenge, we aim to assess the level of precision and accuracy of the modelling techniques that are currently fast enough to handle of order 50 lenses, via the blind analysis of simulated data sets. The results in Rungs 1 and 2 show that methods that use only the point source positions tend to have lower precision ( $10\!-\!20{{\ \rm per\ cent}}$ ) while remaining accurate. In Rung 2, the methods that exploit the full information of the imaging and kinematic data sets can recover H[SUB]0[/SUB] within the target accuracy (|A| < 2 per cent) and precision (<6 per cent per system), even in the presence of a poorly known point spread function and complex source morphology. A post-unblinding analysis of Rung 3 showed the numerical precision of the ray-traced cosmological simulations to be insufficient to test lens modelling methodology at the percent level, making the results difficult to interpret. A new challenge with improved simulations is needed to make further progress in the investigation of systematic uncertainties. For completeness, we present the Rung 3 results in an appendix and use them to discuss various approaches to mitigating against similar subtle data generation effects in future blind challenges. [less ▲]

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See detailHOLISMOKES. III. Achromatic phase of strongly lensed Type Ia supernovae
Huber, S.; Suyu, S. H.; Noebauer, U. M. et al

in Astronomy and Astrophysics (2021), 646

To use strongly lensed Type Ia supernovae (LSNe Ia) for cosmology, a time-delay measurement between the multiple supernova (SN) images is necessary. The sharp rise and decline of SN Ia light curves make ... [more ▼]

To use strongly lensed Type Ia supernovae (LSNe Ia) for cosmology, a time-delay measurement between the multiple supernova (SN) images is necessary. The sharp rise and decline of SN Ia light curves make them promising for measuring time delays, but microlensing can distort these light curves and therefore add large uncertainties to the measurements. An alternative approach is to use color curves where uncertainties due to microlensing are significantly reduced for a certain period of time known as the achromatic phase. In this work, we investigate in detail the achromatic phase, testing four different SN Ia models with various microlensing configurations. We find on average an achromatic phase of around three rest-frame weeks or longer for most color curves, but the spread in the duration of the achromatic phase (due to different microlensing maps and filter combinations) is quite large and an achromatic phase of just a few days is also possible. Furthermore, the achromatic phase is longer for smoother microlensing maps and lower macro-magnifications. From our investigations, we do not find a strong dependency on the SN model or on asymmetries in the SN ejecta. We find that six rest-frame LSST color curves exhibit features such as extreme points or turning points within the achromatic phase, which make them promising for time-delay measurements; however, only three of the color curves are independent. These curves contain combinations of rest-frame bands u, g, r, and i, and to observe them for typical LSN Ia redshifts, it would be ideal to cover (observer-frame) filters r, i, z, y, J, and H. If follow-up resources are restricted, we recommend r, i, and z as the bare minimum for using color curves and/or light curves since LSNe Ia are bright in these filters and observational uncertainties are lower than in the infrared regime. With additional resources, infrared observations in y, J, and H would be useful for obtaining color curves of SNe, especially at redshifts above ∼0.8 when they become critical. [less ▲]

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See detailTesting the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars
Ding, Xuheng; Treu, Tommaso; Birrer, Simon et al

in Monthly Notices of the Royal Astronomical Society (2021), 501

One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ( $\mathcal {M}_{\rm BH}$ ) and the properties of ... [more ▼]

One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ( $\mathcal {M}_{\rm BH}$ ) and the properties of its active host galaxy is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed AGNs with deep Hubble Space Telescope imaging, using the lens modelling code LENSTRONOMY to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, we infer the host galaxy stellar mass based on stellar population models. $\mathcal {M}_{\rm BH}$ are estimated from broad emission lines using standard methods. Our results are in good agreement with recent work based on non-lensed AGNs, demonstrating the potential of using strongly lensed AGNs to extend the study of the correlations to higher redshifts. At the moment, the sample size of lensed AGNs is small and thus they provide mostly a consistency check on systematic errors related to resolution for non-lensed AGNs. However, the number of known lensed AGNs is expected to increase dramatically in the next few years, through dedicated searches in ground- and space-based wide-field surveys, and they may become a key diagnostic of black holes and galaxy co-evolution. [less ▲]

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See detailGaia GraL: Gaia DR2 Gravitational Lens Systems. VI. Spectroscopic Confirmation and Modeling of Quadruply-Imaged Lensed Quasars
Stern, D.; Djorgovski, S. G.; Krone-Martins, A. et al

in Astrophysical Journal (2021)

Combining the exquisite angular resolution of Gaia with optical light curves and WISE photometry, the Gaia Gravitational Lenses group (GraL) uses machine learning techniques to identify candidate strongly ... [more ▼]

Combining the exquisite angular resolution of Gaia with optical light curves and WISE photometry, the Gaia Gravitational Lenses group (GraL) uses machine learning techniques to identify candidate strongly lensed quasars, and has confirmed over two dozen new strongly lensed quasars from the Gaia Data Release 2. This paper reports on the 12 quadruply-imaged quasars identified by this effort to date, which is approximately a 20% increase in the total number of confirmed quadruply-imaged quasars. We discuss the candidate selection, spectroscopic follow-up, and lens modeling. We also report our spectroscopic failures as an aid for future investigations. [less ▲]

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See detailSpectropolarimetry of the changing-look active galactic nucleus Mrk 1018
Hutsemekers, Damien ULiege; Agis-Gonzalez, Beatriz ULiege; Marin, F. et al

in Astronomy and Astrophysics (2020), 644

We have obtained new spectropolarimetric observations at visible wavelengths of the changing-look active galactic nucleus (AGN) Mrk 1018. The AGN direct spectrum shows an extremely weak continuum with ... [more ▼]

We have obtained new spectropolarimetric observations at visible wavelengths of the changing-look active galactic nucleus (AGN) Mrk 1018. The AGN direct spectrum shows an extremely weak continuum with faint broad Hβ and Hα emission lines. Both lines can be fit with a single very broad emission line component of full width at half maximum FWHM ≃ 7200 km s[SUP]-1[/SUP], with no evidence of the additional 3000 km s[SUP]-1[/SUP]-wide component that was previously detected. While this is in agreement with line formation in a Keplerian disk, the line profile variability suggests that the broad emission line region is likely more complex. The continuum polarization of Mrk 1018 is low; it is not higher in the current faint state compared to the past bright state, confirming that dust obscuration is not the mechanism at the origin of the change of look. The polarization profile of the Hα line is asymmetric with no rotation of the polarization angle, which possibly reveals line formation in a polar outflow. Alternatively, the polarization profile may be the consequence of a time delay between the direct and the polarized light. Interestingly, the polarization signatures predicted for broad lines emitted around supermassive binary black holes are not observed. <P />Based on observations made with the ESO VLT at the Paranal Observatory under program ID 104.B-0620. [less ▲]

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See detailHOLISMOKES. I. Highly Optimised Lensing Investigations of Supernovae, Microlensing Objects, and Kinematics of Ellipticals and Spirals
Suyu, S. H.; Huber, S.; Cañameras, R. et al

in Astronomy and Astrophysics (2020), 644

We present the HOLISMOKES programme on strong gravitational lensing of supernovae (SNe) as a probe of SN physics and cosmology. We investigate the effects of microlensing on early-phase SN Ia spectra ... [more ▼]

We present the HOLISMOKES programme on strong gravitational lensing of supernovae (SNe) as a probe of SN physics and cosmology. We investigate the effects of microlensing on early-phase SN Ia spectra using four different SN explosion models. We find that distortions of SN Ia spectra due to microlensing are typically negligible within ten rest-frame days after a SN explosion (< 1% distortion within the 1σ spread and ≲10% distortion within the 2σ spread). This shows the great prospects of using lensed SNe Ia to obtain intrinsic early-phase SN spectra for deciphering SN Ia progenitors. As a demonstration of the usefulness of lensed SNe Ia for cosmology, we simulate a sample of mock lensed SN Ia systems that are expected to have accurate and precise time-delay measurements in the era of the Rubin Observatory Legacy Survey of Space and Time (LSST). Adopting realistic yet conservative uncertainties on their time-delay distances and lens angular diameter distances, of 6.6% and 5%, respectively, we find that a sample of 20 lensed SNe Ia would allow us to constrain the Hubble constant (H[SUB]0[/SUB]) with 1.3% uncertainty in the flat ΛCDM cosmology. We find a similar constraint on H[SUB]0[/SUB] in an open ΛCDM cosmology, while the constraint degrades to 3% in a flat wCDM cosmology. We anticipate lensed SNe to be an independent and powerful probe of SN physics and cosmology in the upcoming LSST era. [less ▲]

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See detailThe impact of mass map truncation on strong lensing simulations
Van de Vyvere, Lyne ULiege; Sluse, Dominique ULiege; Mukherjee, Sampath ULiege et al

in Astronomy and Astrophysics (2020), 644

Strong gravitational lensing is a powerful tool to measure cosmological parameters and to study galaxy evolution mechanisms. However, quantitative strong lensing studies often require mock observations ... [more ▼]

Strong gravitational lensing is a powerful tool to measure cosmological parameters and to study galaxy evolution mechanisms. However, quantitative strong lensing studies often require mock observations. To capture the full complexity of galaxies, the lensing galaxy is often drawn from high resolution, dark matter only or hydro-dynamical simulations. These have their own limitations, but the way we use them to emulate mock lensed systems may also introduce significant artefacts. In this work we identify and explore the specific impact of mass truncation on simulations of strong lenses by applying different truncation schemes to a fiducial density profile with conformal isodensity contours. Our main finding is that improper mass truncation can introduce undesired artificial shear. The amplitude of the spurious shear depends on the shape and size of the truncation area as well as on the slope and ellipticity of the lens density profile. Due to this effect, the value of H0 or the shear amplitude inferred by modelling those systems may be biased by several percents. However, we show that the effect becomes negligible provided that the lens projected map extends over at least 50 times the Einstein radius. [less ▲]

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See detailTDCOSMO. IV. Hierarchical time-delay cosmography - joint inference of the Hubble constant and galaxy density profiles
Birrer, S.; Shajib, A. J.; Galan, A. et al

in Astronomy and Astrophysics (2020), 643

The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H[SUB]0[/SUB] = 73.3[SUB]-1.8[/SUB][SUP]+1.7[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP], describing ... [more ▼]

The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H[SUB]0[/SUB] = 73.3[SUB]-1.8[/SUB][SUP]+1.7[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP], describing deflector mass density profiles by either a power-law or stars (constant mass-to-light ratio) plus standard dark matter halos. The mass-sheet transform (MST) that leaves the lensing observables unchanged is considered the dominant source of residual uncertainty in H[SUB]0[/SUB]. We quantify any potential effect of the MST with a flexible family of mass models, which directly encodes it, and they are hence maximally degenerate with H[SUB]0[/SUB]. Our calculation is based on a new hierarchical Bayesian approach in which the MST is only constrained by stellar kinematics. The approach is validated on mock lenses, which are generated from hydrodynamic simulations. We first applied the inference to the TDCOSMO sample of seven lenses, six of which are from H0LiCOW, and measured H[SUB]0[/SUB] = 74.5[SUB]-6.1[/SUB][SUP]+5.6[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP]. Secondly, in order to further constrain the deflector mass density profiles, we added imaging and spectroscopy for a set of 33 strong gravitational lenses from the Sloan Lens ACS (SLACS) sample. For nine of the 33 SLAC lenses, we used resolved kinematics to constrain the stellar anisotropy. From the joint hierarchical analysis of the TDCOSMO+SLACS sample, we measured H[SUB]0[/SUB] = 67.4[SUB]-3.2[/SUB][SUP]+4.1[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP]. This measurement assumes that the TDCOSMO and SLACS galaxies are drawn from the same parent population. The blind H0LiCOW, TDCOSMO-only and TDCOSMO+SLACS analyses are in mutual statistical agreement. The TDCOSMO+SLACS analysis prefers marginally shallower mass profiles than H0LiCOW or TDCOSMO-only. Without relying on the form of the mass density profile used by H0LiCOW, we achieve a ∼5% measurement of H[SUB]0[/SUB]. While our new hierarchical analysis does not statistically invalidate the mass profile assumptions by H0LiCOW - and thus the H[SUB]0[/SUB] measurement relying on them - it demonstrates the importance of understanding the mass density profile of elliptical galaxies. The uncertainties on H[SUB]0[/SUB] derived in this paper can be reduced by physical or observational priors on the form of the mass profile, or by additional data. <P />The full analysis is available at <A href="https://github.com/TDCOSMO/hierarchy_analysis_2020_public">http://https://github.com/TDCOSMO/hierarchy_analysis_2020_public</A>. [less ▲]

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See detailTDCOSMO. II. Six new time delays in lensed quasars from high-cadence monitoring at the MPIA 2.2 m telescope
Millon, M.; Courbin, F.; Bonvin, V. et al

in Astronomy and Astrophysics (2020), 642

We present six new time-delay measurements obtained from R[SUB]c[/SUB]-band monitoring data acquired at the Max Planck Institute for Astrophysics (MPIA) 2.2 m telescope at La Silla observatory between ... [more ▼]

We present six new time-delay measurements obtained from R[SUB]c[/SUB]-band monitoring data acquired at the Max Planck Institute for Astrophysics (MPIA) 2.2 m telescope at La Silla observatory between October 2016 and February 2020. The lensed quasars HE 0047-1756, WG 0214-2105, DES 0407-5006, 2M 1134-2103, PSJ 1606-2333, and DES 2325-5229 were observed almost daily at high signal-to-noise ratio to obtain high-quality light curves where we can record fast and small-amplitude variations of the quasars. We measured time delays between all pairs of multiple images with only one or two seasons of monitoring with the exception of the time delays relative to image D of PSJ 1606-2333. The most precise estimate was obtained for the delay between image A and image B of DES 0407-5006, where τ[SUB]AB[/SUB] = -128.4[SUB]-3.8[/SUB][SUP]+3.5[/SUP] d (2.8% precision) including systematics due to extrinsic variability in the light curves. For HE 0047-1756, we combined our high-cadence data with measurements from decade-long light curves from previous COSMOGRAIL campaigns, and reach a precision of 0.9 d on the final measurement. The present work demonstrates the feasibility of measuring time delays in lensed quasars in only one or two seasons, provided high signal-to-noise ratio data are obtained at a cadence close to daily. <P />All light curves presented in this paper are only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/642/A193">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/642/A193</A> [less ▲]

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See detailCOSMOGRAIL XIX: Time delays in 18 strongly lensed quasars from 15 years of optical monitoring
Millon, M.; Courbin, F.; Bonvin, V. et al

in Astronomy and Astrophysics (2020), 640

We present the results of 15 years of monitoring of lensed quasars conducted by the COSMOGRAIL program at the Leonhard Euler 1.2m Swiss Telescope. The decade-long light curves of 23 lensed QSOs are ... [more ▼]

We present the results of 15 years of monitoring of lensed quasars conducted by the COSMOGRAIL program at the Leonhard Euler 1.2m Swiss Telescope. The decade-long light curves of 23 lensed QSOs are presented for the first time. We complement our data set with other monitoring data available in the literature to measure the time delays in 18 systems, among which 9 reach a relative precision better than 15% for at least one time delay. To achieve this, we develop an automated version of the curve-shifting toolbox PyCS to ensure robust estimation of the time delay in the presence of microlensing while accounting for the errors due to imperfect representation of microlensing. We also reanalyze the previously published time delays of RX J1131$-$1231 and HE 0435$-$1223, adding respectively 6 and 2 new seasons of monitoring and confirming the previous time-delay measurements. When the time delay measurement is possible, we correct the light curves of the lensed images from their time delay and present the difference curves to highlight the microlensing signal contained in the data. This is to date the largest sample of decade-long lens monitoring data, useful to measure $H_0$, to measure the size of quasar accretion disks with microlensing, and to study quasar variability. [less ▲]

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See detailCosmic dissonance: are new physics or systematics behind a short sound horizon?
Arendse, Nikki; Wojtak, Radosław J.; Agnello, Adriano et al

in Astronomy and Astrophysics (2020), 639

Context. Persistent tension between low-redshift observations and the cosmic microwave background radiation (CMB), in terms of two fundamental distance scales set by the sound horizon r[SUB]d[/SUB] and ... [more ▼]

Context. Persistent tension between low-redshift observations and the cosmic microwave background radiation (CMB), in terms of two fundamental distance scales set by the sound horizon r[SUB]d[/SUB] and the Hubble constant H[SUB]0[/SUB], suggests new physics beyond the Standard Model, departures from concordance cosmology, or residual systematics. <BR /> Aims: The role of different probe combinations must be assessed, as well as of different physical models that can alter the expansion history of the Universe and the inferred cosmological parameters. <BR /> Methods: We examined recently updated distance calibrations from Cepheids, gravitational lensing time-delay observations, and the tip of the red giant branch. Calibrating the baryon acoustic oscillations and type Ia supernovae with combinations of the distance indicators, we obtained a joint and self-consistent measurement of H[SUB]0[/SUB] and r[SUB]d[/SUB] at low redshift, independent of cosmological models and CMB inference. In an attempt to alleviate the tension between late-time and CMB-based measurements, we considered four extensions of the standard ΛCDM model. <BR /> Results: The sound horizon from our different measurements is r[SUB]d[/SUB] = (137 ± 3[SUP]stat.[/SUP] ± 2[SUP]syst.[/SUP]) Mpc based on absolute distance calibration from gravitational lensing and the cosmic distance ladder. Depending on the adopted distance indicators, the combined tension in H[SUB]0[/SUB] and r[SUB]d[/SUB] ranges between 2.3 and 5.1 σ, and it is independent of changes to the low-redshift expansion history. We find that modifications of ΛCDM that change the physics after recombination fail to provide a solution to the problem, for the reason that they only resolve the tension in H[SUB]0[/SUB], while the tension in r[SUB]d[/SUB] remains unchanged. Pre-recombination extensions (with early dark energy or the effective number of neutrinos N[SUB]eff[/SUB] = 3.24 ± 0.16) are allowed by the data, unless the calibration from Cepheids is included. <BR /> Conclusions: Results from time-delay lenses are consistent with those from distance-ladder calibrations and point to a discrepancy between absolute distance scales measured from the CMB (assuming the standard cosmological model) and late-time observations. New proposals to resolve this tension should be examined with respect to reconciling not only the Hubble constant but also the sound horizon derived from the CMB and other cosmological probes. [less ▲]

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See detailTDCOSMO. I. An exploration of systematic uncertainties in the inference of H[SUB]0[/SUB] from time-delay cosmography
Millon, M.; Galan, A.; Courbin, F. et al

in Astronomy and Astrophysics (2020), 639

Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble constant, H[SUB]0[/SUB]. As part of an ongoing effort to uncover and control systematic uncertainties ... [more ▼]

Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble constant, H[SUB]0[/SUB]. As part of an ongoing effort to uncover and control systematic uncertainties, we investigate three potential sources: 1- stellar kinematics, 2- line-of- sight effects, and 3- the deflector mass model. To meet this goal in a quantitative way, we reproduced the H0LiCOW/SHARP/STRIDES (hereafter TDCOSMO) procedures on a set of real and simulated data, and we find the following. First, stellar kinematics cannot be a dominant source of error or bias since we find that a systematic change of 10% of measured velocity dispersion leads to only a 0.7% shift on H[SUB]0[/SUB] from the seven lenses analyzed by TDCOSMO. Second, we find no bias to arise from incorrect estimation of the line-of-sight effects. Third, we show that elliptical composite (stars + dark matter halo), power-law, and cored power-law mass profiles have the flexibility to yield a broad range in H[SUB]0[/SUB] values. However, the TDCOSMO procedures that model the data with both composite and power-law mass profiles are informative. If the models agree, as we observe in real systems owing to the "bulge- halo" conspiracy, H[SUB]0[/SUB] is recovered precisely and accurately by both models. If the two models disagree, as in the case of some pathological models illustrated here, the TDCOSMO procedure either discriminates between them through the goodness of fit, or it accounts for the discrepancy in the final error bars provided by the analysis. This conclusion is consistent with a reanalysis of six of the TDCOSMO (real) lenses: the composite model yields H[SUB]0[/SUB] = 74.0[SUB]-1.8[/SUB][SUP]+1.7[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP], while the power-law model yields 74.2[SUB]-1.6[/SUB][SUP]+1.6[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP]. In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO. [less ▲]

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See detailH0LiCOW - XI. A weak lensing measurement of the external convergence in the field of the lensed quasar B1608+656 using HST and Subaru deep imaging
Tihhonova, O.; Courbin, F.; Harvey, D. et al

in Monthly Notices of the Royal Astronomical Society (2020), 498

We investigate the environment and line of sight (LoS) of the H0LiCOW (H[SUB]0[/SUB] Lenses in COSMOGRAIL's Wellspring) lens B1608+656 using Subaru Suprime-Cam and the Hubble Space Telescope (HST) to ... [more ▼]

We investigate the environment and line of sight (LoS) of the H0LiCOW (H[SUB]0[/SUB] Lenses in COSMOGRAIL's Wellspring) lens B1608+656 using Subaru Suprime-Cam and the Hubble Space Telescope (HST) to perform a weak lensing analysis. We compare three different methods to reconstruct the mass map of the field, i.e. the standard Kaiser-Squires inversion coupled with inpainting and Gaussian or wavelet filtering, and ${\rm {\small {glimpse}}}$ , a method based on sparse regularization of the shear field. We find no substantial difference between the 2D mass reconstructions, but we find that the ground-based data are less sensitive to small-scale structures than the space-based observations. Marginalizing over the results obtained with all the reconstruction techniques applied to the two available HST filters F606W and F814W, we estimate the external convergence, κ[SUB]ext[/SUB], at the position of B1608+656 is $\kappa _{\mathrm{ext}}= 0.11^{+0.06}_{-0.04}$ , where the error bars correspond, respectively, to the 16th and 84th quartiles. This result is compatible with previous estimates using the number counts technique, suggesting that B1608+656 resides in an overdense LoS, but with a completely different technique. Using our mass reconstructions, we also compare the convergence at the position of several groups of galaxies in the field of B1608+656 with the mass measurements using various analytical mass profiles, and find that the weak lensing results favour truncated halo models. [less ▲]

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See detailVizieR Online Data Catalog: R-band light curves of 23 lensed QSOs (Millon+, 2020)
Millon, M.; Courbin, F.; Bonvin, V. et al

Textual, factual or bibliographical database (2020)

Data associated with paper Millon et al. 2020, A&A 639, A101. R-band cosmograil light curves of lensed quasars taken at the Euler 1.2m Swiss telescope with the EulerCAM and EulerC2 instrument. Additional ... [more ▼]

Data associated with paper Millon et al. 2020, A&A 639, A101. R-band cosmograil light curves of lensed quasars taken at the Euler 1.2m Swiss telescope with the EulerCAM and EulerC2 instrument. Additional data taken at the SMARTS 1.3m telescope with the ANDICAM optical/ infrared camera are also included for SDSS J0924+0219 (MacLeod et al., 2015ApJ...806..258M, Cat. J/ApJ/806/258). <P />For HE 0435-1223 and RX J1131-1231, data taken at the 1.5m telescope at the Maidanak Observatory, the Mercator Belgian telescope and at the SMARTS 1.3 m telescope are included (Courbin et al. 2011A&A...536A..53C, Cat, J/A+A/536/A53, Tewes et al. 2013A&A...553A.120T, 2013A&A...556A..22T, Cat. J/A+A/556/A22). For SDSS J1515+1511, we had the data from Shalyapin & Goicoechea (2017ApJ...836...14S) from the Liverpool Telescope. <P />(5 data files). [less ▲]

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See detailVLA and ALMA observations of the lensed radio-quiet quasar SDSS J0924+0219: a molecular structure in a 3 μJy radio source
Badole, Shruti; Jackson, Neal; Hartley, Philippa et al

in Monthly Notices of the Royal Astronomical Society (2020), 496

We present Karl G. Jansky Very Large Array (VLA) and Atacama Large Millimetre Array (ALMA) observations of SDSS J0924+0219, a z = 1.524 radio-quiet lensed quasar with an intrinsic radio flux density of ... [more ▼]

We present Karl G. Jansky Very Large Array (VLA) and Atacama Large Millimetre Array (ALMA) observations of SDSS J0924+0219, a z = 1.524 radio-quiet lensed quasar with an intrinsic radio flux density of about 3 $\, \mu$ Jy. The four lensed images are clearly detected in the radio continuum and the CO(5-4) line, whose centroid is at z = 1.5254 ± 0.0001, with a marginal detection in the submillimetre continuum. The molecular gas displays ordered motion, in a structure approximately 1-2.5 kpc in physical extent, with typical velocities of 50-100 km s[SUP]-1[/SUP]. Our results are consistent with the radio emission being emitted from the same region, but not with a point source of radio emission. SDSS J0924+0219 shows an extreme anomaly in the flux ratios of the two merging images in the optical continuum and broad emission lines, suggesting the influence of microlensing by stars in the lensing galaxy. We find the flux ratio in the radio, submillimetre continuum and CO lines to be slightly greater than 1 but much less than that in the optical, which can be reproduced with a smooth galaxy mass model and an extended source. Our results, supported by a microlensing simulation, suggest that the most likely explanation for the optical flux anomaly is indeed microlensing. [less ▲]

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