J/A+A/697/A139 r-band light curves of 22 lensed QSOs (Dux+, 2025)
TDCOSMO. XVII. New time delays in 22 lensed quasars from optical monitoring
with the ESO-VST 2.6m and MPG 2.2m telescopes.
Dux F., Millon M., Galan A., Paic E., Lemon C., Courbin F., Bonvin V.,
Anguita T., Auger M., Birrer S., Buckley-Geer E., Fassnacht C.D.,
Frieman J., McMahon R.G., Marshall P.J., Melo A., Motta V., Neira F.,
Sluse D., Suyu S.H., Treu T., Agnello A., Avila F., Chan J., Chijani M.,
Rojas K., Hempel A., Hempel M., Kim S., Eigenthaler P., Lachaume R.,
Rabus M.
<Astron. Astrophys. 697, A139 (2025)>
=2025A&A...697A.139D 2025A&A...697A.139D (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Gravitational lensing ; Photometry ; Optical
Keywords: methods: data analysis - surveys - distance scale
Abstract:
We present new time delays, the main ingredient of time delay
cosmography, for 22 lensed quasars resulting from high-cadence r-band
monitoring on the 2.6m ESO VLT Survey Telescope and
Max-Planck-Gesellschaft 2.2m telescope. Each lensed quasar was
typically monitored for one to four seasons, often shared between the
two telescopes to mitigate the interruptions forced by the COVID-19
pandemic. The sample of targets consists of 19 quadruply and 3 doubly
imaged quasars, which received a total of 1918 hours on-sky time split
in 21581 wide-field frames, each of 320 seconds. In a given field, the
5-σ depth of the combined exposures typically reaches the 27th
magnitude, while that of single visits is 24.5mag - similar to the
expected depth of the upcoming Vera-Rubin LSST. The fluxes of the
different lensed images of the targets were reliably de-blended,
providing not only light curves with photometric precision down to the
photon noise limit, but also high resolution models of the targets
whose features and astrometry were systematically confirmed in Hubble
Space Telescope imaging. This was made possible thanks to a new
photometric pipeline, lightcurver, and the forward modelling method
STARRED. Finally, the time delays between pairs of curves and their
uncertainties were estimated taking into account the degeneracy due to
microlensing, and for the first time the full covariance matrices of
the delay pairs are provided. Of note, this survey, with 13 square
degrees, has applications beyond that of time delays, such as the
study of the structure function of the multiple high-redshift quasars
present in the footprint at a new high both in terms of depth and
frequency. The reduced images will be available through the European
Southern Observatory Science Portal.
Description:
Deblended r-band light curves of 22 lensed quasars from the
Paranal/VST and La Silla/2.2m telescopes. The data points with
telescope label "2p2" were taken in the Rc (ESO WFI #844) filter.
Those with telescope label "VST" were taken in the SDSS-r filter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
targets.dat 52 22 Target list
lc/* . 22 Individual light curve files
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See also:
J/A+A/488/481 : Time delays and H0 from WFI J2033-4723 (Vuissoz+, 2008)
J/A+A/536/A53 : R-band light curves of HE 0435-1223 (Courbin+, 2011)
J/A+A/553/A121 : 2 lensed quasars light curves (Eulaers+, 2013)
J/A+A/556/A22 : R-band light curves of RX J1131-1231 (Tewes+, 2013)
J/A+A/557/A44 : Doubly lensed quasar SDSS J1001+5027 (Rathna Kumar+, 2013)
J/MNRAS/465/4914 : R-band light curves of HE 0435-1223 (Bonvin+, 2017)
J/A+A/609/A71 : R-band light curves of DES J0408-5359 (Courbin+, 2018)
J/A+A/616/A183 : R-band light curves of PG 1115+080 (Bonvin+, 2018)
J/A+A/629/A97 : R-band light curves of WFI2033-4723 (Bonvin+, 2019)
J/A+A/640/A105 : R-band light curves of 23 lensed QSOs (Millon+, 2020)
J/A+A/642/A193 : Rc-band light curves of 6 lensed QSOs (Millon+, 2020)
Byte-by-byte Description of file: targets.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Name of the lensed quasar
16- 23 F8.4 deg RAdeg Right ascension (J2000)
25- 33 F9.5 deg DEdeg Declination (J2000)
35- 52 A18 --- FileName Name of the light curve file in subdirectory lc
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Byte-by-byte Description of file: lc/*
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Bytes Format Units Label Explanations
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1- 18 F18.12 --- MJD Modified Julian Date
20- 37 F18.15 mag rmag r band magnitude
39- 59 F21.19 mag e_rmag r band magnitude uncertainty
61- 62 A2 --- LensLabel [A B C D AB AD] Label of the lensed quasar
image at hand
64- 75 A12 --- Tel Telescope that captured the data point
(2p2, ECAM, VST, LCOMuscat3, LCOnotMuscat)
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Acknowledgements:
Frederic Dux, duxfrederic(at)gmail.com
References:
Millon et al., Paper I 2020A&A...639A.101M 2020A&A...639A.101M
Millon et al., Paper II 2020A&A...642A.193M 2020A&A...642A.193M, Cat. J/A+A/642/A193
GilmaN et al., Paper III 2020A&A...642A.194G 2020A&A...642A.194G
Birrer et al., Paper IV 2020A&A...643A.165B 2020A&A...643A.165B
Birrer & Treu, Paper V 2021A&A...649A..61B 2021A&A...649A..61B
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(End) Patricia Vannier [CDS] 10-Apr-2025