A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses

Momcheva, Ivelina; Williams, Kurtis A.; Cool, R. J.; Keeton, Charles R.; Zabludoff, Ann I.

doi:10.1088/0067-0049/219/2/29

Cited by 40 publications

(68 citation statements)

References 162 publications

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“…The falling sensitivity of our redshift catalog (Momcheva et al 2015) results in few groups above z0.6. Four of nine of the lenses with z>0.6 either have only a photometric redshift or an uncertain spectroscopic redshift, so we do not assign them group membership.…”

Section: Lens Groupsmentioning

confidence: 81%

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A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H₀

Wilson

Zabludoff

Keeton

et al. 2017

ApJ

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Strong gravitational lensing provides an independent measurement of the Hubble parameter (H 0 ). One remaining systematic is a bias from the additional mass due to a galaxy group at the lens redshift or along the sightline. We quantify this bias for more than 20 strong lenses that have well-sampled sightline mass distributions, focusing on the convergence κ and shear γ. In 23% of these fields, a lens group contributes 1% convergence bias; in 57%, there is a similarly significant line-of-sight group. For the nine time-delay lens systems, H 0 is overestimated by 11 2 3 -+ % on average when groups are ignored. In 67% of fields with total 0.01  k , line-of-sight groups contribute 2 ´more convergence than do lens groups, indicating that the lens group is not the only important mass. Lens environment affects the ratio of four (quad) to two (double) image systems; all seven quads have lens groups while only 3 of 10 doubles do, and the highest convergences due to lens groups are in quads. We calibrate the γ-κ relation: log 1.94 0.34 log tot tot) with an rms scatter of 0.34 dex. Although shear can be measured directly from lensed images, unlike convergence, it can be a poor predictor of convergence; for 19% of our fields, κ is 2  g. Thus, accurate cosmology using strong gravitational lenses requires precise measurement and correction for all significant structures in each lens field.

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Section: Lens Groupsmentioning

confidence: 81%

“…The lens sample selection is described in Momcheva et al (2015). It depended in part on the ancillary data available at the Wilson et al (2016).…”

Section: Sample Selectionmentioning

confidence: 99%

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H₀

Wilson

Zabludoff

Keeton

et al. 2017

ApJ

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“…This means that there may be other galaxies within this magnitude range and radius from the lens which are also part of the galaxy group associated with the lensing galaxy, but which are missed due to spectroscopic incompleteness. In Section 5.1.3 we have specifically computed the lensing properties of this group, based on its physical properties derived by Momcheva et al (2015). As a result, when we compute κ ext at the location of the lens, using the weighted number counts approach, we must remove the galaxies which are part of this group, as the convergence from the group has already been included in the lensing models, and must not be double-counted.…”

Section: Appendix D: Accounting For the Missing Galaxy Group Members mentioning

confidence: 99%

A SHARP view of H0LiCOW: H0 from three time-delay gravitational lens systems with adaptive optics imaging

Chen

Fassnacht

Suyu

et al. 2019

Monthly Notices of the Royal Astronomical Society

195

167

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We present the measurement of the Hubble Constant, H 0 , 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 each lens, we combine new adaptive optics (AO) imaging from the Keck Telescope, obtained as part of the SHARP AO effort, with Hubble Space Telescope (HST ) imaging, velocity dispersion measurements, and a description of the line-of-sight mass distribution to build an accurate and precise lens mass model. This mass model is then combined with the COSMOGRAIL measured time delays in these systems to determine H 0 . We do both an AO-only and an AO+HST analysis of the systems and find that AO and HST results are consistent. After unblinding, the AO-only analysis gives H 0 = 82.8 +9.4 −8.3 km s −1 Mpc −1 for PG 1115+080, H 0 = 70.1 +5.3 −4.5 km s −1 Mpc −1 for HE 0435−1223, and H 0 = 77.0 +4.0 −4.6 km s −1 Mpc −1 for RXJ 1131−1231. The joint AOonly result for the three lenses is H 0 = 75.6 +3.2 −3.3 km s −1 Mpc −1 . The joint result of the AO+HST analysis for the three lenses is H 0 = 76.8 +2.6−2.6 km s −1 Mpc −1 . All of the above results assume a flat Λ cold dark matter cosmology with a uniform prior on Ω m in [0.05, 0.5] and H 0 in [0, 150] km s −1 Mpc −1 . This work is a collaboration of the SHARP and H0LiCOW teams, and shows that AO data can be used as the high-resolution imaging component in lens-based measurements of H 0 . The full time-delay cosmography results from a total of six strongly lensed systems are presented in a companion paper.

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“…The mean-field-dynamo model predicts that the axisymmetric mode is the strongest mode excited in a galactic disk and that the random field is expected to dominate over the coherent field 29 , as observed here. On-going star formation in this z = 0.439 galaxy, indicated by strong O[II] lines in its spectrum 12,30 , and subsequent supernova explosions can drive turbulence and therefore the alpha-effect, which is a necessary ingredient for the mean-field dynamo 11,29 .…”

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confidence: 99%

Detection of microgauss coherent magnetic fields in a galaxy five billion years ago

et al. 2017

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Magnetic fields play a pivotal role in the physics of interstellar medium in galaxies 1 , but there are few observational constraints on how they evolve across cosmic time 2-7 . Spatially resolved synchrotron polarization maps at radio wavelengths reveal well-ordered largescale magnetic fields in nearby galaxies 1,8,9 that are believed to grow from a seed field via a dynamo effect 10,11 . To directly test and characterize this theory requires magnetic field strength and geometry measurements in cosmologically distant galaxies, which are

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A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses

Cited by 40 publications

References 162 publications

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H₀

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H₀

A SHARP view of H0LiCOW: H0 from three time-delay gravitational lens systems with adaptive optics imaging

Detection of microgauss coherent magnetic fields in a galaxy five billion years ago

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A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses

Cited by 40 publications

References 162 publications

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H0

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H0

A SHARP view of H0LiCOW: H0 from three time-delay gravitational lens systems with adaptive optics imaging

Detection of microgauss coherent magnetic fields in a galaxy five billion years ago

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A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H₀

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for H₀