J/A+A/557/A44 The doubly lensed quasar SDSS J1001+5027 (Rathna Kumar+, 2013)
COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses
XIV. Time delay of the doubly lensed quasar SDSS J1001+5027.
Rathna Kumar S., Tewes M., Stalin C.S., Courbin F., Asfandiyarov I.,
Meylan G., Eulaers E., Prabhu T.P., Magain P., Van Winckel H.,
Ehgamberdiev Sh.
<Astron. Astrophys. 557, A44 (2013)>
=2013A&A...557A..44R 2013A&A...557A..44R
ADC_Keywords: QSOs ; Gravitational lensing ; Photometry, RI
Keywords: gravitational lensing: strong - cosmological parameters -
quasars: individual: SDSS J1001+5027
Abstract:
This paper presents optical R-band light curves and the time delay of
the doubly imaged gravitationally lensed quasar SDSS J1001+5027 at a
redshift of 1.838. We have observed this target for more than six
years, between March 2005 and July 2011, using the 1.2-m Mercator
Telescope, the 1.5-m telescope of the Maidanak Observatory and the 2-m
Himalayan Chandra Telescope. Our resulting light curves are composed
of 443 independent epochs, and show strong intrinsic quasar
variability, with an amplitude of the order of 0.2 magnitudes. From
this data, we measure the time delay using five different methods, all
relying on distinct approaches. One of these techniques is a new
development presented in this paper. All our time-delay measurements
are perfectly compatible. By combining them, we conclude that image A
is leading B by 119.3±3.3 days (1σ, 2.8%), including
systematic errors. It has been shown recently that such accurate
time-delay measurements offer a highly complementary probe of dark
energy and spatial curvature, as they independently constrain the
Hubble constant. The next mandatory step towards using SDSS J1001+5027
in this context will be the measurement of the redshift of the lensing
galaxy, in combination with deep HST imaging.
Description:
These data are R-band light curves of the doubly lensed quasar SDSS
J1001+5027, as displayed in Fig. 4 of the paper. They cover 6.5 years,
from March 2005 to July 2011.
The light curves are obtained using deconvolution photometry of images
from 3 different telescopes, for a total of 443 epochs. Several quasar
variability features strongly constrain the time delay between the
quasar images.
Objects:
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RA (2000) DE Designation(s)
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10 01 28.61 +50 27 57.0 SDSS J1001+5027 = SDSS J100128.61+502756.9
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig4.dat 54 443 R-band light curves of SDSS J1001+5027
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Byte-by-byte Description of file: fig4.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD Heliocentric Julian date
15- 21 F7.5 mag RmagA [0.061/0.351] Relative magnitude of quasar image A
23- 29 F7.5 mag e_RmagA Magnitude uncertainty of quasar image A
31- 37 F7.5 mag RmagB [0.490/0.752] Relative magnitude of quasar image B
39- 45 F7.5 mag e_RmagB Magnitude uncertainty of quasar image B
47- 54 A8 --- Tel Telescope used (1)
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Note (1): Telescope as follows:
Mercator = the 1.2-m Mercator Telescope located at the Roque de los Muchachos
Observatory on La Palma (Spain)
Maidanak = the 1.5-m telescope of the Maidanak Observatory in Pamir Alai
(Uzbekistan)
HCT = the 2-m Himalayan Chandra Telescope (HCT) located at the Indian
Astronomical Observatory in Hanle (India)
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Acknowledgement:
Malte Tewes, malte.tewes( at )epfl.ch,
Ecole polytechnique federale de Lausanne
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(End) Malte Tewes [EPFL] 08-Jul-2013