Time delays in the gravitationally lensed quasar H1413+117 (Cloverleaf)
The quadruple quasar H1413+117 (zs = 2.56) has been monitored with the 2.0 m Liverpool Telescope in the r Sloan band from 2008 February to July. This optical follow-up leads to accurate light curves of the four quasar images (A–D), which are defined by 33 epochs of observation and an average photome...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2010 |
| País: | España |
| Institución: | Universidad de Cantabria (UC) |
| Repositorio: | UCrea Repositorio Abierto de la Universidad de Cantabria |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.unican.es:10902/28126 |
| Acceso en línea: | https://hdl.handle.net/10902/28126 |
| Access Level: | acceso abierto |
| Palabra clave: | Gravitational lensing Quasars: individual |
| Sumario: | The quadruple quasar H1413+117 (zs = 2.56) has been monitored with the 2.0 m Liverpool Telescope in the r Sloan band from 2008 February to July. This optical follow-up leads to accurate light curves of the four quasar images (A–D), which are defined by 33 epochs of observation and an average photometric error of ∼15 mmag. We then use the observed (intrinsic) variations of ∼50–100 mmag to measure the three time delays for the lens system for the first time (1σ confidence intervals): ΔτAB = −17 ± 3, ΔτAC = −20 ± 4, and ΔτAD = 23 ± 4 days (Δτij = τj − τi; B and C are leading, while D is trailing). Although time delays for lens systems are often used to obtain the Hubble constant (H0), the unavailability of the spectroscopic lens redshift (zl) in the system H1413+117 prevents a determination of H0 from the measured delays. In this paper, the new time-delay constraints and a concordance expansion rate (H0 = 70 km s−1 Mpc−1) allow us to improve the lens model and to estimate the previously unknown zl. Our 1σ estimate zl = 1.88+0.09−0.11 is an example of how to infer the redshift of very distant galaxies via gravitational lensing. |
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