Cristian E. Rusu
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View article: A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly
A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly Open
We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517, identified in a survey for QSOs by infrared selection. Hubble Space Telescope imaging reveals a quadruply lensed system in a cusp configuration, with a ma…
View article: A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly
A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly Open
We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517, identified in a survey for QSOs by infrared selection. Hubble Space Telescope imaging reveals a quadruply lensed system in a cusp configuration, with a ma…
View article: TDCOSMO
TDCOSMO Open
The importance of alternative methods for measuring the Hubble constant, such as time-delay cosmography, is highlighted by the recent Hubble tension. It is paramount to thoroughly investigate and rule out systematic biases in all measureme…
View article: TDCOSMO. IX. Systematic comparison between lens modelling software programs: time delay prediction for WGD 2038-4008
TDCOSMO. IX. Systematic comparison between lens modelling software programs: time delay prediction for WGD 2038-4008 Open
The importance of alternative methods for measuring the Hubble constant, such as time-delay cosmography, is highlighted by the recent Hubble tension. It is paramount to thoroughly investigate and rule out systematic biases in all measureme…
View article: Strongly lensed candidates from the HSC transient survey
Strongly lensed candidates from the HSC transient survey Open
We present a lensed quasar search based on the variability of lens systems in the Hyper Suprime-Cam (HSC) transient survey. Starting from 101 353 variable objects with i -band photometry in the HSC transient survey, we used a variability-b…
View article: Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI) – VII. Discovery and confirmation of three strongly lensed quasars†
Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI) – VII. Discovery and confirmation of three strongly lensed quasars† Open
We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogues. Images of HSC J091843.27–022007.5 show a red galaxy with two blue point sources at either…
View article: Erratum: Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars
Erratum: Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars Open
The paper 'Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars' was published inMNRAS, 483, 4, 5649-5671 (2019). The coordinate values of the image positions in table 4 were wron…
View article: H_0 from Lensed Quasars
H_0 from Lensed Quasars Open
Strong gravitational lens systems with time delays between the multiple images are a powerful probe of cosmology, particularly of the Hubble constant (H0). The H0 Lenses In COSMOGRAIL's Wellspring (H0LiCOW) project has measured H0 from len…
View article: Testing the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars
Testing the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars Open
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 …
View article: STRIDES: Spectroscopic and photometric characterization of the environment and effects of mass along the line of sight to the gravitational lenses DES J0408–5354 and WGD 2038–4008
STRIDES: Spectroscopic and photometric characterization of the environment and effects of mass along the line of sight to the gravitational lenses DES J0408–5354 and WGD 2038–4008 Open
In time-delay cosmography, three of the key ingredients are (1) determining the velocity dispersion of the lensing galaxy, (2) identifying galaxies and groups along the line of sight with sufficient proximity and mass to be included in the…
View article: Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI)
Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI) Open
Context. Strong lenses are extremely useful probes of the distribution of matter on galaxy and cluster scales at cosmological distances, however, they are rare and difficult to find. The number of currently known lenses is on the order of …
View article: Spin parity of spiral galaxies II: a catalogue of 80 k spiral galaxies using big data from the Subaru Hyper Suprime-Cam survey and deep learning
Spin parity of spiral galaxies II: a catalogue of 80 k spiral galaxies using big data from the Subaru Hyper Suprime-Cam survey and deep learning Open
We report an automated morphological classification of galaxies into S-wise spirals, Z-wise spirals, and non-spirals using big image data taken from Subaru/Hyper Suprime-Cam (HSC) Survey and a convolutional neural network (CNN)-based deep …
View article: H0LiCOW – XI. A weak lensing measurement of the external convergence in the field of the lensed quasar B1608+656 using <i>HST</i> and Subaru deep imaging
H0LiCOW – XI. A weak lensing measurement of the external convergence in the field of the lensed quasar B1608+656 using <i>HST</i> and Subaru deep imaging Open
We investigate the environment and line of sight (LoS) of the H0LiCOW (H0 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 …
View article: Survey of Gravitationally lensed Objects in HSC Imaging (SuGOHI) – V. Group-to-cluster scale lens search from the HSC–SSP Survey
Survey of Gravitationally lensed Objects in HSC Imaging (SuGOHI) – V. Group-to-cluster scale lens search from the HSC–SSP Survey Open
We report the largest sample of candidate strong gravitational lenses belonging to the Survey of Gravitationally lensed Objects in HSC Imaging for group-to-cluster scale (SuGOHI-c) systems. These candidates are compiled from the S18A data …
View article: VizieR Online Data Catalog: Redshift catalog of HE 0435-1223 field-of-view (Sluse+, 2017)
VizieR Online Data Catalog: Redshift catalog of HE 0435-1223 field-of-view (Sluse+, 2017) Open
Our data set combines multi-object spectroscopy obtained at Gemini- South, Keck, and ESO-Paranal observatories. The catalogue contains 534 unique objects, including 368 redshifts exclusively reported by MOM15 (Momcheva et al., 2015, Cat. J…
View article: Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps
Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps Open
Strong lenses are extremely useful probes of the distribution of matter on galaxy and cluster scales at cosmological distances, but are rare and difficult to find. The number of currently known lenses is on the order of 1,000. We wish to u…
View article: STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408−5354
STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408−5354 Open
We present a blind time-delay cosmographic analysis for the lens system DES J0408−5354. This system is extraordinary for the presence of two sets of multiple images at different redshifts, which provide the opportunity to obtain more infor…
View article: The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2017/2018 follow-up campaign: discovery of 10 lensed quasars and 10 quasar pairs
The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2017/2018 follow-up campaign: discovery of 10 lensed quasars and 10 quasar pairs Open
We report the results of the STRong lensing Insights into the Dark Energy Survey (STRIDES) follow-up campaign of the late 2017/early 2018 season. We obtained spectra of 65 lensed quasar candidates with ESO Faint Object Spectrograph and Cam…
View article: Discovery of an unusually compact lensed Lyman-break galaxy from the Hyper Suprime-Cam Survey
Discovery of an unusually compact lensed Lyman-break galaxy from the Hyper Suprime-Cam Survey Open
We report the serendipitous discovery of HSC J0904–0102, a quadruply lensed Lyman-break galaxy (LBG) in the Survey of Gravitationally-lensed Objects in Hyper Suprime-Cam Imaging (SuGOHI). Owing to its point-like appearance, the source was …
View article: Survey of Gravitationally lensed Objects in HSC Imaging (SuGOHI)
Survey of Gravitationally lensed Objects in HSC Imaging (SuGOHI) Open
Strong gravitationally lensed quasars provide a powerful means to study galaxy evolution and cosmology. We use C HITAH , which is an algorithm used to hunt for new lens systems, particularly lensed quasars, in the Hyper Suprime-Cam Subaru …
View article: X-ray study of the double source plane gravitational lens system Eye of Horus observed with <i>XMM–Newton</i>
X-ray study of the double source plane gravitational lens system Eye of Horus observed with <i>XMM–Newton</i> Open
A double source plane (DSP) system is a precious probe for the density profile of distant galaxies and cosmological parameters. However, these measurements could be affected by the surrounding environment of the lens galaxy. Thus, it is im…
View article: Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). IV. Lensed quasar search in the HSC survey
Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). IV. Lensed quasar search in the HSC survey Open
Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. We use Chitah to hunt for new lens systems in the Hyper Suprime$-$Cam Subaru Strategic Program (HSC SSP) S16A. We present 46 lens candida…
View article: H0LiCOW XII. Lens mass model of WFI2033 − 4723 and blind measurement of its time-delay distance and H0
H0LiCOW XII. Lens mass model of WFI2033 − 4723 and blind measurement of its time-delay distance and H0 Open
We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033 − 4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 yr of data obt…
View article: H0LiCOW – XIII. A 2.4 per cent measurement of H0 from lensed quasars: 5.3σ tension between early- and late-Universe probes
H0LiCOW – XIII. A 2.4 per cent measurement of H0 from lensed quasars: 5.3σ tension between early- and late-Universe probes Open
We present a measurement of the Hubble constant (H0) and other cosmological parameters from a joint analysis of six gravitationally lensed quasars with measured time delays. All lenses except the first are analysed blindly with respect to …
View article: A SHARP view of H0LiCOW: H0 from three time-delay gravitational lens systems with adaptive optics imaging
A SHARP view of H0LiCOW: H0 from three time-delay gravitational lens systems with adaptive optics imaging Open
We present the measurement of the Hubble constant, H0, with three strong gravitational lens systems. We describe a blind analysis of both PG 1115+080 and HE 0435−1223 as well as an extension of our previous analysis of RXJ 1131−1231. For e…
View article: H0LiCOW – X. Spectroscopic/imaging survey and galaxy-group identification around the strong gravitational lens system WFI 2033−4723
H0LiCOW – X. Spectroscopic/imaging survey and galaxy-group identification around the strong gravitational lens system WFI 2033−4723 Open
Galaxies and galaxy groups located along the line of sight towards gravitationally lensed quasars produce high-order perturbations of the gravitational potential at the lens position. When these perturbation are too large, they can induce …
View article: COSMOGRAIL
COSMOGRAIL Open
We present new measurements of the time delays of WFI2033−4723. The data sets used in this work include 14 years of data taken at the 1.2 m Leonhard Euler Swiss telescope, 13 years of data from the SMARTS 1.3 m telescope at Las Campanas Ob…
View article: A search for gravitationally lensed quasars and quasar pairs in Pan-STARRS1: spectroscopy and sources of shear in the diamond 2M1134−2103
A search for gravitationally lensed quasars and quasar pairs in Pan-STARRS1: spectroscopy and sources of shear in the diamond 2M1134−2103 Open
We present results of a systematic search for gravitationally lensed quasars in Pan-STARRS1. Our final sample of candidates comprises of 91 systems, not including 25 rediscovered lensed quasars and quasar pairs. In the absence of spectrosc…
View article: H0LiCOW – IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant
H0LiCOW – IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant Open
We present a blind time-delay strong lensing (TDSL) cosmographic analysis of\nthe doubly imaged quasar SDSS 1206+4332. We combine the relative time delay\nbetween the quasar images, Hubble Space Telescope imaging, the Keck stellar\nvelocit…
View article: Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars
Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars Open
Strong-gravitational lens systems with quadruply imaged quasars (quads) are unique probes to address several fundamental problems in cosmology and astrophysics. Although they are intrinsically very rare, ongoing and planned wide-field deep…