The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses

C. Y. Peng, Christopher D Impey, E. E. Falco, C. S. Kochanek, J. Lehár, B. A. Mcleod, H. W. Rix, C. R. Keeton, J. A. Muñoz

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Deep HST/NICMOS H-band (F160W) observations of the z = 1.96 quasar pair Q1634+267A and B reveal no signs of a lens galaxy to a 1 σ threshold of ≃22.5 mag. The minimum luminosity for a normal lens galaxy would be a 6L* galaxy at z ≃ 0.5, which is 650 times greater than our detection threshold. Our observation constrains the infrared mass-to-light ratio (M/L) of any putative, early-type, lens galaxy to (M/L)H ≳ 690 h65 (1200 h65) for Ω0 = 0.1 (1.0) and H0 = 65 h65 km s-1 Mpc-1. We would expect to detect a galaxy somewhere in the field because of the very strong Mg II absorption lines at z = 1.1262 in the Q1634+267A spectrum, but the HST H-band, I-band (F785LP), and V-band (F555W) images require that any associated galaxy be very underluminous ≲0.1L*H (1.0L*I) if it lies within ≲40 h-165 (100 h-165) kpc from Q1634+267A and B. While the large image separation (3″.85) and the lack of a lens galaxy strongly favor interpreting Q1634+267A and B as a binary quasar system, the spectral similarity remains a puzzle. We estimate that, at most, 0.06% of randomly selected quasar pairs would have spectra as similar to each other as the spectra of Q1634+267A and B. Moreover, spectral similarities observed for the 14 known quasar pairs are significantly greater than would be expected for an equivalent sample of randomly selected field quasars. Depending on how strictly we define similarity, we estimate that only 0.01%-3% of randomly drawn samples of 14 quasar pairs would have as many similar pairs as the observational sample.

Original languageEnglish (US)
Pages (from-to)572-581
Number of pages10
JournalAstrophysical Journal
Volume524
Issue number2 PART 1
StatePublished - Oct 20 1999

Fingerprint

quasars
lenses
galaxies
mass to light ratios
thresholds
estimates
extremely high frequencies
luminosity
detection

Keywords

  • Gravitational lensing
  • Quasars: General

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Peng, C. Y., Impey, C. D., Falco, E. E., Kochanek, C. S., Lehár, J., Mcleod, B. A., ... Muñoz, J. A. (1999). The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses. Astrophysical Journal, 524(2 PART 1), 572-581.

The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses. / Peng, C. Y.; Impey, Christopher D; Falco, E. E.; Kochanek, C. S.; Lehár, J.; Mcleod, B. A.; Rix, H. W.; Keeton, C. R.; Muñoz, J. A.

In: Astrophysical Journal, Vol. 524, No. 2 PART 1, 20.10.1999, p. 572-581.

Research output: Contribution to journalArticle

Peng, CY, Impey, CD, Falco, EE, Kochanek, CS, Lehár, J, Mcleod, BA, Rix, HW, Keeton, CR & Muñoz, JA 1999, 'The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses', Astrophysical Journal, vol. 524, no. 2 PART 1, pp. 572-581.
Peng CY, Impey CD, Falco EE, Kochanek CS, Lehár J, Mcleod BA et al. The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses. Astrophysical Journal. 1999 Oct 20;524(2 PART 1):572-581.
Peng, C. Y. ; Impey, Christopher D ; Falco, E. E. ; Kochanek, C. S. ; Lehár, J. ; Mcleod, B. A. ; Rix, H. W. ; Keeton, C. R. ; Muñoz, J. A. / The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses. In: Astrophysical Journal. 1999 ; Vol. 524, No. 2 PART 1. pp. 572-581.
@article{7058066124d24f288ece65fc39dc4644,
title = "The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses",
abstract = "Deep HST/NICMOS H-band (F160W) observations of the z = 1.96 quasar pair Q1634+267A and B reveal no signs of a lens galaxy to a 1 σ threshold of ≃22.5 mag. The minimum luminosity for a normal lens galaxy would be a 6L* galaxy at z ≃ 0.5, which is 650 times greater than our detection threshold. Our observation constrains the infrared mass-to-light ratio (M/L) of any putative, early-type, lens galaxy to (M/L)H ≳ 690 h65 (1200 h65) for Ω0 = 0.1 (1.0) and H0 = 65 h65 km s-1 Mpc-1. We would expect to detect a galaxy somewhere in the field because of the very strong Mg II absorption lines at z = 1.1262 in the Q1634+267A spectrum, but the HST H-band, I-band (F785LP), and V-band (F555W) images require that any associated galaxy be very underluminous ≲0.1L*H (1.0L*I) if it lies within ≲40 h-165 (100 h-165) kpc from Q1634+267A and B. While the large image separation (3″.85) and the lack of a lens galaxy strongly favor interpreting Q1634+267A and B as a binary quasar system, the spectral similarity remains a puzzle. We estimate that, at most, 0.06{\%} of randomly selected quasar pairs would have spectra as similar to each other as the spectra of Q1634+267A and B. Moreover, spectral similarities observed for the 14 known quasar pairs are significantly greater than would be expected for an equivalent sample of randomly selected field quasars. Depending on how strictly we define similarity, we estimate that only 0.01{\%}-3{\%} of randomly drawn samples of 14 quasar pairs would have as many similar pairs as the observational sample.",
keywords = "Gravitational lensing, Quasars: General",
author = "Peng, {C. Y.} and Impey, {Christopher D} and Falco, {E. E.} and Kochanek, {C. S.} and J. Leh{\'a}r and Mcleod, {B. A.} and Rix, {H. W.} and Keeton, {C. R.} and Mu{\~n}oz, {J. A.}",
year = "1999",
month = "10",
day = "20",
language = "English (US)",
volume = "524",
pages = "572--581",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2 PART 1",

}

TY - JOUR

T1 - The quasar pair Q1634+267A,B and the binary QSO versus dark lens hypotheses

AU - Peng, C. Y.

AU - Impey, Christopher D

AU - Falco, E. E.

AU - Kochanek, C. S.

AU - Lehár, J.

AU - Mcleod, B. A.

AU - Rix, H. W.

AU - Keeton, C. R.

AU - Muñoz, J. A.

PY - 1999/10/20

Y1 - 1999/10/20

N2 - Deep HST/NICMOS H-band (F160W) observations of the z = 1.96 quasar pair Q1634+267A and B reveal no signs of a lens galaxy to a 1 σ threshold of ≃22.5 mag. The minimum luminosity for a normal lens galaxy would be a 6L* galaxy at z ≃ 0.5, which is 650 times greater than our detection threshold. Our observation constrains the infrared mass-to-light ratio (M/L) of any putative, early-type, lens galaxy to (M/L)H ≳ 690 h65 (1200 h65) for Ω0 = 0.1 (1.0) and H0 = 65 h65 km s-1 Mpc-1. We would expect to detect a galaxy somewhere in the field because of the very strong Mg II absorption lines at z = 1.1262 in the Q1634+267A spectrum, but the HST H-band, I-band (F785LP), and V-band (F555W) images require that any associated galaxy be very underluminous ≲0.1L*H (1.0L*I) if it lies within ≲40 h-165 (100 h-165) kpc from Q1634+267A and B. While the large image separation (3″.85) and the lack of a lens galaxy strongly favor interpreting Q1634+267A and B as a binary quasar system, the spectral similarity remains a puzzle. We estimate that, at most, 0.06% of randomly selected quasar pairs would have spectra as similar to each other as the spectra of Q1634+267A and B. Moreover, spectral similarities observed for the 14 known quasar pairs are significantly greater than would be expected for an equivalent sample of randomly selected field quasars. Depending on how strictly we define similarity, we estimate that only 0.01%-3% of randomly drawn samples of 14 quasar pairs would have as many similar pairs as the observational sample.

AB - Deep HST/NICMOS H-band (F160W) observations of the z = 1.96 quasar pair Q1634+267A and B reveal no signs of a lens galaxy to a 1 σ threshold of ≃22.5 mag. The minimum luminosity for a normal lens galaxy would be a 6L* galaxy at z ≃ 0.5, which is 650 times greater than our detection threshold. Our observation constrains the infrared mass-to-light ratio (M/L) of any putative, early-type, lens galaxy to (M/L)H ≳ 690 h65 (1200 h65) for Ω0 = 0.1 (1.0) and H0 = 65 h65 km s-1 Mpc-1. We would expect to detect a galaxy somewhere in the field because of the very strong Mg II absorption lines at z = 1.1262 in the Q1634+267A spectrum, but the HST H-band, I-band (F785LP), and V-band (F555W) images require that any associated galaxy be very underluminous ≲0.1L*H (1.0L*I) if it lies within ≲40 h-165 (100 h-165) kpc from Q1634+267A and B. While the large image separation (3″.85) and the lack of a lens galaxy strongly favor interpreting Q1634+267A and B as a binary quasar system, the spectral similarity remains a puzzle. We estimate that, at most, 0.06% of randomly selected quasar pairs would have spectra as similar to each other as the spectra of Q1634+267A and B. Moreover, spectral similarities observed for the 14 known quasar pairs are significantly greater than would be expected for an equivalent sample of randomly selected field quasars. Depending on how strictly we define similarity, we estimate that only 0.01%-3% of randomly drawn samples of 14 quasar pairs would have as many similar pairs as the observational sample.

KW - Gravitational lensing

KW - Quasars: General

UR - http://www.scopus.com/inward/record.url?scp=0033589148&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033589148&partnerID=8YFLogxK

M3 - Article

VL - 524

SP - 572

EP - 581

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2 PART 1

ER -