An optical time-delay for the lensed BAL quasar HE 2149-2745

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dc.contributor.authorBurud, I
dc.contributor.authorCourbin, F
dc.contributor.authorMagain, P
dc.contributor.authorLidman, C
dc.contributor.authorHutsemékers, D
dc.contributor.authorKneib, JP
dc.contributor.authorHjorth, J
dc.contributor.authorBrewer, J
dc.contributor.authorPompei, E
dc.contributor.authorGermany, L
dc.contributor.authorPritchard, J
dc.contributor.authorJaunsen, AO
dc.contributor.authorLetawe, G
dc.contributor.authorMeylan, G
dc.date.accessioned2025-01-21T01:30:30Z
dc.date.available2025-01-21T01:30:30Z
dc.date.issued2002
dc.description.abstractWe present optical V and i-band light curves of the gravitationally lensed BAL quasar HE 2149-2745. The data, obtained with the 1.5 m Danish Telescope (ESO-La Silla) between October 1998 and December 2000, are the first from a long-term project aimed at monitoring selected lensed quasars in the Southern Hemisphere. A time delay of 103+/-12 days is determined from the light curves. In addition, VLT/FORS1 spectra of HE 2149 2745 are deconvolved in order to obtain the spectrum of the faint lensing galaxy, free of any contamination by the bright nearby two quasar images. By cross-correlating the spectrum with galaxy-templates we obtain a tentative redshift estimate of z = 0.495+/-0:01. Adopting this redshift, a Omega = 0.3, Lambda = 0.7 cosmology, and a chosen analytical lens model, our time-delay measurement yields a Hubble constant of H-0 = 66+/-8 km s(-1) Mpc(-1) (1sigma error) with an estimated systematic error of +/-3 km s(-1) Mpc(-1). Using non-parametric models yields H-0 = 65+/-8 km s(-1) Mpc(-1) (1sigma error) and confirms that the lens exhibits a very dense/concentrated mass profile. Finally, we note, as in other cases, that the flux ratio between the two quasar components is wavelength dependent. While the flux ratio in the broad emission lines-equal to 3.7-remains constant with wavelength, the continuum of the brighter component is bluer. Although the data do not rule out extinction of one quasar image relative to the other as a possible explanation, the effect could also be produced by differential microlensing by stars in the lensing galaxy.
dc.fuente.origenWOS
dc.identifier.doi10.1051/0004-6361:20011731
dc.identifier.issn0004-6361
dc.identifier.urihttps://doi.org/10.1051/0004-6361:20011731
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/96790
dc.identifier.wosidWOS:000174183500010
dc.issue.numero1
dc.language.isoen
dc.pagina.final81
dc.pagina.inicio71
dc.revistaAstronomy & astrophysics
dc.rightsacceso restringido
dc.subjectgravitational lensing
dc.subjectquasars : individual : HE 2149-2745
dc.subjectcosmological parameters
dc.titleAn optical time-delay for the lensed BAL quasar HE 2149-2745
dc.typeartículo
dc.volumen383
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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