J/A+A/605/L8 Spectra of lensed QSO PSOJ0147 (Lee, 2017)
Accurate spectroscopic redshift of the multiply lensed quasar PSOJ0147 from the
Pan-STARRS survey.
Lee C.-H.
<Astron. Astrophys. 605, L8 (2017)>
=2017A&A...605L...8L 2017A&A...605L...8L (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; QSOs ; Spectroscopy
Keywords: gravitational lensing: strong - quasars: general -
cosmology: observations
Abstract:
The gravitational lensing time delay method provides a one-step
determination of the Hubble constant (H0) with an uncertainty level on
par with the cosmic distance ladder method. However, to further
investigate the nature of the dark energy, a H0 estimate down to 1%
level is greatly needed. This requires dozens of strongly lensed
quasars that are yet to be delivered by ongoing and forthcoming
all-sky surveys.
In this work we aim to determine the spectroscopic redshift of
PSOJ0147, the first strongly lensed quasar candidate found in the
Pan-STARRS survey. The main goal of our work is to derive an accurate
redshift estimate of the background quasar for cosmography.
To obtain timely spectroscopically follow-up, we took advantage of the
fast-track service programme that is carried out by the Nordic Optical
Telescope. Using a grism covering 3200-9600Å, we identified
prominent emission line features, such as Lyα, NV, OI, CII,
SiIV, CIV, and [CIII] in the spectra of the background quasar of the
PSOJ0147 lens system. This enables us to determine accurately the
redshift of the background quasar.
The spectrum of the background quasar exhibits prominent absorption
features bluewards of the strong emission lines, such as Lyα,
NV, and CIV. These blue absorption lines indicate that the background
source is a broad absorption line (BAL) quasar. Unfortunately, the BAL
features hamper an accurate determination of redshift using the
above-mentioned strong emission lines. Nevertheless, we are able to
determine a redshift of 2.341±0.001 from three of the four lensed
quasar images with the clean forbidden line [CIII]. In addition, we
also derive a maximum outflow velocity of ∼9800km/s with the broad
absorption features bluewards of the CIV emission line. This value of
maximum outflow velocity is in good agreement with other BAL quasars.
Description:
Spectra of the three quasar images A, B, and C are presented.
Objects:
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RA (2000) DE Designation(s)
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01 47 10.154 +46 30 40.58 PSOJ0147
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
quasar_a.dat 21 1290 Quasar image A spectrum
quasar_b.dat 21 1290 Quasar image B spectrum
quasar_c.dat 21 1290 Quasar image C spectrum
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Byte-by-byte Description of file: quasar_a.dat quasar_b.dat quasar_c.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Wavelength (Angstrom)
10- 21 E12.7 10mW/m2/nm Flux Flux (erg/s/cm+2/Å)
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Acknowledgements:
Lee, Chien-Hsiu, leech(at)naoj.org
(End) Lee C.-H. [Subaru Telescope, NAOJ, Japan], P. Vannier [CDS] 20-Sep-2017