CLASH: Extending galaxy strong lensing to small physical scales with distant sources highly magnified by galaxy cluster members
- Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)
- Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Universitè Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif sur Yvette (France)
- Dipartimento di Fisica, Università degli Studi di Trieste, via G. B. Tiepolo 12, I-34143 Trieste (Italy)
- INAF-Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, I-34131 Trieste (Italy)
- INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-80131 Napoli (Italy)
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122 Ferrara (Italy)
- INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy)
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
- Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
- Institut für Theoretische Astrophysik, Zentrum für Astronomie, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany)
- Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n, E-18008 Granada (Spain)
- Leiden Observatory, Leiden University, P.O. Box 9513, NL-2333 Leiden (Netherlands)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States)
- Department of Theoretical Physics, University of the Basque Country, P.O. Box 644, E-48080 Bilbao (Spain)
We present a complex strong lensing system in which a double source is imaged five times by two early-type galaxies. We take advantage in this target of the extraordinary multi-band photometric data set obtained as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, complemented by the spectroscopic measurements of the VLT/VIMOS and FORS2 follow-up campaign. We use a photometric redshift value of 3.7 for the source and confirm spectroscopically the membership of the two lenses to the galaxy cluster MACS J1206.2–0847 at redshift 0.44. We exploit the excellent angular resolution of the HST/ACS images to model the two lenses in terms of singular isothermal sphere profiles and derive robust effective velocity dispersion values of 97 ± 3 and 240 ± 6 km s{sup –1}. Interestingly, the total mass distribution of the cluster is also well characterized by using only the local information contained in this lensing system, which is located at a projected distance of more than 300 kpc from the cluster luminosity center. According to our best-fitting lensing and composite stellar population models, the source is magnified by a total factor of 50 and has a luminous mass of approximately (1.0 ± 0.5) × 10{sup 9} M {sub ☉} (assuming a Salpeter stellar initial mass function). By combining the total and luminous mass estimates of the two lenses, we measure luminous over total mass fractions projected within the effective radii of 0.51 ± 0.21 and 0.80 ± 0.32. Remarkably, with these lenses we can extend the analysis of the mass properties of lens early-type galaxies by factors that are approximately two and three times smaller than previously done with regard to, respectively, velocity dispersion and luminous mass. The comparison of the total and luminous quantities of our lenses with those of astrophysical objects with different physical scales, like massive early-type galaxies and dwarf spheroidals, reveals the potential of studies of this kind for improving our knowledge about the internal structure of galaxies. These studies, made possible thanks to the CLASH survey, will allow us to go beyond the current limits posed by the available lens samples in the field.
- OSTI ID:
- 22357030
- Journal Information:
- Astrophysical Journal, Vol. 786, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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