The dark halo of the main lens galaxy in QSO 0957+561

Abstract

We present an analysis of infrared/optical/ultraviolet spectra of the two images of the first gravitationally lensed quasar Q0957+561A, B. The Hubble Space Telescope observations of Q0957+561A and Q0957+561B are separated in time by the known time delay in this system, so we can directly deduce the flux ratios. These flux ratios of images lead to important information on the dark halo of the main lens galaxy (a giant elliptical at redshift z = 0.36). Our measurements for the continuum are in good agreement with extinction in the elliptical galaxy and a small fraction of mass in collapsed objects (no need for gravitational microlensing). From the continuum and emission line ratios, we also show evidence in favour of the existence of a network of compact dusty clouds.

arXiv comment5 pages, 2 figures + 1 table, accepted for publication in MNRAS Letters (more details at http://grupos.unican.es/glendama/)

References in corpus (19)

• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• The MACHO Project: Microlensing Results from 5.7 Years of LMC Observations
• MACHO Project Limits on Black Hole Dark Matter in the 1-30 Solar Mass Range
• Dust and Extinction Curves in Galaxies with z>0: The Interstellar Medium of Gravitational Lens Galaxies
• EROS and MACHO Combined Limits on Planetary Mass Dark Matter in the Galactic Halo
• An optical time-delay estimate for the double gravitational lens system B1600+434
• Disentangling microlensing and differential extinction in the double QSO HE0512-3329
• A microlensing measurement of the size of the broad emission line region in the lensed QSO 2237+0305
• Evidence for a source size of less than 2000 AU in Quasar 2237+0305
• Improved Parameters and New Lensed Features for Q0957+561 from WFPC2 Imaging
• BVRI photometry of QSO 0957+561A, B: Observations, new reduction method and time delay
• Short-timescale Fluctuations in the Difference Light Curves of QSO 0957+561A,B: Microlensing or Noise?
• Observable consequences of cold clouds as dark matter
• New VR magnification ratios of QSO 0957+561
• A Large Brightness Enhancement of the QSO 0957+561 A Component
• Five nights of intensive R- and V-band photometry of QSO 0957+561A,B
• GLITP Optical Monitoring of QSO 0957+561: VR Light Curves and Variability
• Spectroscopy of the Lens Galaxy of Q0957+561A,B. Implications of a possible central massive dark object

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