J/ApJ/836/14 LCs & spectra of SDSS J1515+1511 lens system (Shalyapin+, 2017)
Doubly imaged quasar SDSS J1515+1511: time delay and lensing galaxies.
Shalyapin V.N., Goicoechea L.J.
<Astrophys. J., 836, 14-14 (2017)>
=2017ApJ...836...14S 2017ApJ...836...14S (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; Photometry, SDSS ; Spectroscopy ; QSOs
Keywords: gravitational lensing: strong; quasars: individual: "SDSS J1515+1511"
Abstract:
We analyze new optical observations of the gravitational lens system
SDSS J1515+1511. These include a 2.6-year photometric monitoring with
the Liverpool Telescope (LT) in the r band, as well as a spectroscopic
follow-up with the LT and the Gran Telescopio Canarias (GTC). Our
r-band LT light curves cover a quiescent microlensing period of the
doubly imaged quasar at zs=2.049, which permits us to robustly
estimate the time delay between the two images A and B: 211±5d
(1σ confidence interval; A is leading). Unfortunately, the main
lensing galaxy (G1) is so faint and close to the bright quasar that it
is not feasible to accurately extract its spectrum through the GTC
data. However, assuming the putative redshift zG1=0.742, the GTC and
LT spectra of the distant quasar are used to discuss the macrolens
magnification, and the extinction and microlensing effects in G1. The
new constraints on the time delay and macrolens magnification ratio
essentially do not change previous findings on the mass scale of G1
and external shear, while the redshift of the lensing mass is found to
be consistent with the assumed value of zG1. This is clear evidence
that G1 is indeed located at zG1=0.742. From the GTC data, we also
obtain the redshift of two additional objects (the secondary galaxy G2
and a new absorption system) and discuss their possible roles in the
lens scenario.
Description:
We conducted a photometric monitoring campaign of SDSS J1515+1511 from
early February of 2014 to mid September of 2016, i.e., for 2.6yr with
an average sampling rate of about two nights every week. All optical
observations were performed with the 2.0m fully robotic Liverpool
Telescope (LT) at the Roque de los Muchachos Observatory, Canary
Islands (Spain).
Deep long-slit spectra of SDSS J1515+1511 were obtained using the
R500B and R500R grisms in the OSIRIS spectrograph on the 10.4m Gran
Telescopio Canarias (GTC). We took a single 1800s exposure with the
blue grism (R500B) on 2015 April 15. We also observed the lens system
with the red grism (R500R) on 2015 April 16. Hence, the new data cover
a wavelength range of 3570-9250Å with a resolving power of ∼300-400.
We observed SDSS J1515+1511 with the SPRAT long-slit spectrograph on
2015 August 16 (red grating) and 2015 August 18 (blue). We have
re-observed the system on 2016 March 17 (blue).
Objects:
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RA (ICRS) DE Designation(s)
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15 15 38.59 +15 11 35.8 SDSS J1515+1511 = [IOR2014] SDSS J1515+1511
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 48 150 *LT r-band light curves of SDSS J1515+1511AB
table2.dat 22 1024 *GTC-OSIRIS-R500B spectra of SDSS J1515+1511AB
table3.dat 29 916 *GTC-OSIRIS-R500R spectra of SDSS J1515+1511ABG1
table4.dat 22 880 *LT-SPRAT-blue/red spectra of SDSS J1515+1511AB
(2015 August)
table5.dat 22 880 *LT-SPRAT-blue spectra of SDSS J1515+1511AB
(2016 March)
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Note on table*dat: See the "Description" section above for the observations
description.
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian Date
11- 16 F6.3 mag rmagA [18/18.3] r-band magnitude of SDSS J1515+1511A
18- 22 F5.3 mag e_rmagA [0.004/0.03] Uncertainty in rmagA
24- 29 F6.3 mag rmagB [18.3/18.7] r-band magnitude of SDSS J1515+1511B
31- 35 F5.3 mag e_rmagB [0.004/0.03] Uncertainty in rmagB
37- 42 F6.3 mag rmagS [18.1/18.2] r-band magnitude of the field
(control) star S
44- 48 F5.3 mag e_rmagS [0.003/0.02] Uncertainty in rmagS
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda [3567/7244] GTC-OSIRIS-R500B spectral
wavelength, in Angstroms
10- 15 F6.3 10-19W/m2/nm FluxA [9.6/95.2] Flux, SDSS J1515+1511A,
in 10-17erg/cm2/s/Å units
17- 22 F6.3 10-19W/m2/nm FluxB [7/58.3] Flux, SDSS J1515+1511B,
in 10-17erg/cm2/s/Å units
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda [4846.6/9252] GTC-OSIRIS-R500R spectral
wavelength, in Angstroms
10- 15 F6.3 10-19W/m2/nm FluxA [5.2/26.3] Flux, SDSS J1515+1511A,
in 10-17erg/cm2/s/Å units
17- 22 F6.3 10-19W/m2/nm FluxB [3.9/19] Flux, SDSS J1515+1511B,
in 10-17erg/cm2/s/Å units
24- 29 F6.3 10-19W/m2/nm FluxG1 [-0.1/1.2] Flux, SDSS J1515+1511G1,
in 10-17erg/cm2/s/Å units
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda [3980.4/8055.8] LT-SPRAT-blue/red spectral
wavelength, in Angstroms
10- 15 F6.3 10-19W/m2/nm FluxA [7.3/51.5] Flux, SDSS J1515+1511A,
in 10-17erg/cm2/s/Å units
17- 22 F6.3 10-19W/m2/nm FluxB [4.5/32] Flux, SDSS J1515+1511B,
in 10-17erg/cm2/s/Å units
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda [3968.4/8060] LT-SPRAT-blue spectral
wavelength, in Angstroms
10- 15 F6.3 10-19W/m2/nm FluxA [7.6/51] Flux, SDSS J1515+1511A,
in 10-17erg/cm2/s/Å units
17- 22 F6.3 10-19W/m2/nm FluxB [5.7/35.1] Flux, SDSS J1515+1511B,
in 10-17erg/cm2/s/Å units
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Sep-2017