Improved mass constraints for two nearby strong-lensing elliptical galaxies from Hubble Space Telescope Imaging

Abstract

We analyse newly obtained Hubble Space Telescope (HST) imaging for two nearby strong lensing elliptical galaxies, SNL-1 (z = 0.03) and SNL-2 (z = 0.05), in order to improve the lensing mass constraints. The imaging reveals previously unseen structure in both the lens galaxies and lensed images. For SNL-1 which has a well resolved source, we break the mass-vs-shear degeneracy using the relative magnification information, and measure a lensing mass of 9.49 $\pm$ 0.15 $\times$ 10${}^{10}$ M${}_{\odot }$, a 7 per cent increase on the previous estimate. For SNL-2 the imaging reveals a bright unresolved component to the source and this presents additional complexity due to possible AGN microlensing or variability. We tentatively use the relative magnification information to constrain the contribution from SNL-2's nearby companion galaxy, measuring a lensing mass of 12.59 $\pm$ 0.30 $\times$ 10${}^{10}$ M${}_{\odot }$, a 9 per cent increase in mass. Our improved lens modelling reduces the mass uncertainty from 5 and 10 per cent to 2 and 3 per cent respectively. Our results support the conclusions of the previous analysis, with newly measured mass excess parameters of 1.17 $\pm$ 0.09 and 0.96 $\pm$ 0.10 for SNL-1 and SNL-2, relative to a Milky-Way like (Kroupa) initial mass function.

MNRAS accepted 1st September 2017

References in corpus (19)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The Structure of Cold Dark Matter Halos
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• On the variation of the Initial Mass Function
• Detailed Structural Decomposition of Galaxy Images
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• A systematic variation of the stellar initial mass function in early-type galaxies
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. II. Results
• Strong Lensing by Galaxies
• The initial mass function of early-type galaxies
• Galaxy Masses
• Quasar Microlensing at High Magnification and the Role of Dark Matter: Enhanced Fluctuations and Suppressed Saddlepoints
• EzGal: A Flexible Interface for Stellar Population Synthesis Models
• The SINFONI Nearby Elliptical Lens Locator Survey: Discovery of two new low-redshift strong lenses and implications for the initial mass function in giant early-type galaxies
• A calibration of the stellar mass fundamental plane at z ~ 0.5 using the micro-lensing induced flux ratio anomalies of macro-lensed quasars
• A giant elliptical galaxy with a lightweight initial mass function
• The 6dF Galaxy Survey: Fundamental Plane Data
• The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints
• Discovery of Strong Lensing by an Elliptical Galaxy at z=0.0345

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• Calibrated, cosmological hydrodynamical simulations with variable IMFs I: Method and effect on global galaxy scaling relations
• Unravelling the Origin of the Counter-Rotating Core in IC 1459 with KMOS and MUSE
• Recovery of the low- and high-mass end slopes of the IMF in massive early-type galaxies using detailed elemental abundances
• Dynamical masses of brightest cluster galaxies II: constraints on the stellar IMF
• Stellar velocity dispersion and initial mass function gradients in dissipationless galaxy mergers
• Comparing Lensing and Stellar Orbital Models of a Nearby Massive Strong-Lens Galaxy
• MNELLS: The MUSE Nearby Early-Type Galaxy Lens Locator Survey
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