J/ApJ/873/117 Monitoring of the double quasar SDSS J1442+4055 (Shalyapin+, 2019)
Gravitationally lensed quasar SDSS J1442+4055: redshifts of lensing galaxies,
time delay, microlensing variability, and intervening metal system at z∼2.
Shalyapin V.N., Goicoechea L.J.
<Astrophys. J., 873, 117 (2019)>
=2019ApJ...873..117S 2019ApJ...873..117S
ADC_Keywords: Gravitational lensing; QSOs; Photometry, RI; Spectra, optical
Galaxies, spectra
Keywords: galaxies: high-redshift ; gravitational lensing: strong ;
quasars: individual (SDSS J1442+4055)
Abstract:
We present r-band photometric monitoring of the two images, A and B,
of the gravitationally lensed quasar SDSS J1442+4055 using the
Liverpool Telescope (LT). From the LT light curves between 2015
December and 2018 August, we derive at once a time delay of
25.0±1.5d (1σ confidence interval; A is leading) and
microlensing magnification gradients below 10-4mag/d. The delay
interval is not expected to be affected by an appreciable
microlensing-induced bias, so it can be used to estimate cosmological
parameters. This paper also focuses on new Gran Telescopio Canarias
(GTC) and LT spectroscopic observations of the lens system. We
determine the redshift of two bright galaxies around the doubly imaged
quasar using LT spectroscopy, while GTC data lead to low-noise
individual spectra of A, B, and the main lensing galaxy, G1. The G1
spectral shape is accurately matched to an early-type galaxy template
at z=0.284, and it has potential for further relevant studies.
Additionally, the quasar spectra show absorption by metal-rich gas at
z∼2. This dusty absorber is responsible for an extinction bump at a
rest-frame wavelength of 2209±2Å, which has strengths of ∼0.47
and 0.76mag/µm for A and B, respectively. In such an intervening
system, the dust-to-gas ratio, gas-phase metallicity indicator [Zn/H],
and dust depletion level [Fe/Zn] are relatively high.
Description:
We have monitored the double quasar SDSS J1442+4055 over three
complete observing seasons from 2015 December 23 to 2018 August 28.
All photometric observations were made in the r band with the IO:O
camera on the 2m Liverpool Telescope (LT). We obtained frames of the
lensed quasar for 135 observing epochs (nights). See Section 2.1.
We also performed spectroscopic observations of SDSS J1442+4055 on
2016 March 5 using the OSIRIS instrument on the 10.4m Gran Telescopio
Canarias (GTC). We took a 2850 (3x950)s GTC-OSIRIS exposure with each
of two grisms, R500B and R500R. See Section 2.2.
In the vicinity of the double quasar, there is a secondary lensing
galaxy (G2). The two galaxies G1 and G2 are <5" apart, so they could
be physically associated. To identify G2 and another bright field
galaxy (G3), both objects were spectroscopically observed on
2016 June 8 with the SPRAT instrument on the LT. See Section 2.3.
Objects:
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RA (2000) DE Designation(s)
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14 42 54.79 +40 55 35.7 SDSS J1442+4055A = [MOK2016] SDSS J1442+4055 A
14 42 54.61 +40 55 35.2 SDSS J1442+4055B = [MOK2016] SDSS J1442+4055 B
14 42 54.70 +40 55 35.4 SDSS J1442+4055G1 = [MOK2016] SDSS J1442+4055 G
14 42 54.53 +40 55 31.3 SDSS J1442+4055G2 = SDSS J144254.52+405531.3
14 42 57.39 +40 55 18.8 SDSS J1442+4055G3 = SDSS J144257.38+405518.8
14 42 49.56 +40 55 19.4 Star S = SDSS J144249.55+405519.4
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 125 LT-IO:O r-band light curves of SDSS J1442+4055AB
table2.dat 48 1074 GTC-OSIRIS-R500B spectra of SDSS J1442+4055ABG1
table3.dat 46 916 GTC-OSIRIS-R500R spectra of SDSS J1442+4055ABG1
table4.dat 22 880 LT-SPRAT spectra of SDSS J1442+4055G2G3
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See also:
II/179 : Southern Spectrophotometric Standards. I + II (Hamuy+ 1992,94)
VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)
VII/286 : SDSS quasar catalog, fourteenth data release (Paris+, 2018)
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
J/A+A/478/701 : Color excess of SDSS QSOs with DLA systems (Vladilo+, 2008)
J/A+A/488/481 : Time delays and H0 from WFI J2033-4723 (Vuissoz+, 2008)
J/A+A/596/A77 : SDSS J1339+1310 spectra and light curves (Goicoechea+, 2016)
J/MNRAS/465/4914 : R-band light curves of HE 0435-1223 (Bonvin+, 2017)
J/ApJ/836/14 : LCs & sp. of SDSS J1515+1511 lens system (Shalyapin+, 2017)
J/A+A/616/A118 : Lensed QSOs LCs & spectral monitoring (Gil-Merino+ 2018)
J/ApJ/860/41 : Spectral & environment data of z∼2 QSO pairs (Lusso+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 d MJD [7379.2/8359] Modified Julian Date; MJD-50000
10- 15 F6.3 mag rmagA [17.9/18.2] r-band magnitude of SDSS J1442+4055A
17- 21 F5.3 mag e_rmagA [0.003/0.02] Uncertainty in rmagA
23- 28 F6.3 mag rmagB [18.9/19.2] r-band magnitude of SDSS J1442+4055B
30- 34 F5.3 mag e_rmagB [0.006/0.03] Uncertainty in rmagB
36- 41 F6.3 mag rmagS [15.9/16.1] r-band magnitude of the field
(control) star S (SDSS J144249.55+405519.4)
43- 47 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 [3426.7/7247.5] Observed wavelength in Å
10- 15 F6.3 0.1nW/m3 FA [1.8/52.1] Flux of SDSS J1442+4055A
in 10-17erg/cm2/s/Å
17- 21 F5.3 0.1nW/m3 e_FA [0.06/1.7] Error in FA
23- 28 F6.3 0.1nW/m3 FB [0.2/22.7] Flux of SDSS J1442+4055B
in 10-17erg/cm2/s/Å
30- 34 F5.3 0.1nW/m3 e_FB [0.05/1.6] Error in FB
36- 42 F7.3 0.1nW/m3 FG1 [-10.1/5.7] Flux of SDSS J1442+4055G1
in 10-17erg/cm2/s/Å
44- 48 F5.3 0.1nW/m3 e_FG1 [0.06/1.7] Error in FG1
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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 [4846.7/9252.9] Observed wavelength in Å
10- 15 F6.3 0.1nW/m3 FA [5.5/31.7] Flux of SDSS J1442+4055A
in 10-17erg/cm2/s/Å
17- 21 F5.3 0.1nW/m3 e_FA [0.04/0.4] Error in FA
23- 28 F6.3 0.1nW/m3 FB [2.8/14.4] Flux of SDSS J1442+4055B
in 10-17erg/cm2/s/Å
30- 34 F5.3 0.1nW/m3 e_FB [0.03/0.3] Error in FB
36- 40 F5.3 0.1nW/m3 FG1 [1.5/6.1] Flux of SDSS J1442+4055G1
in 10-17erg/cm2/s/Å
42- 46 F5.3 0.1nW/m3 e_FG1 [0.04/0.4] Error in FG1
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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 [3984.3/8056.1] Observed wavelength in Å
10- 15 F6.3 0.1nW/m3 FG2 [-7.4/12.7] Flux of SDSS J1442+4055G2;
in 10-17erg/cm2/s/Å
17- 22 F6.3 0.1nW/m3 FG3 [-5.2/11.6] Flux of SDSS J1442+4055G3;
in 10-17erg/cm2/s/Å
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Aug-2020