The parkes quarter-Jansky flat-spectrum sample. 2. New optical spectra and redshift measurements

I. M. Hook; P. A. Shaver; C. A. Jackson; J. V. Wall; K. I. Kellermann

doi:10.1051/0004-6361:20021803

The parkes quarter-Jansky flat-spectrum sample. 2. New optical spectra and redshift measurements

I. M. Hook^*, P. A. Shaver, C. A. Jackson, J. V. Wall, K. I. Kellermann

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

27 Citations (Scopus)

Abstract

We present optical spectra and redshift measurements for 178 flat-spectrum objects from the Parkes quarter-Jansky flat-spectrum sample. These spectra were obtained in order to compile a complete sample of quasars for use in a study of quasar evolution. We present a composite optical spectrum made from the subset of 109 quasars that have flux densities in the range 0.25 Jy < S_2.7 GHz < 0.5 Jy, and make a comparison with a composite for radio-quiet QSOs from the Large Bright Quasar Survey. Our large sample of radio-loud quasars allows us to strengthen previous reports that the Lyα and CIV emission lines have larger equivalent width in radio-loud quasars than radio-quiet QSOs to greater than the 3σ level. However we see no significant difference in the equivalent widths of CIII] or MgII. We also show that the flux decrements across the Lyman-α line (D_A) measured from these spectra show the same trend with redshift as for optically selected QSOs.

Original language	English
Pages (from-to)	469-487
Number of pages	19
Journal	Astronomy and Astrophysics
Volume	399
Issue number	2
DOIs	https://doi.org/10.1051/0004-6361:20021803
Publication status	Published - 2003

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title = "The parkes quarter-Jansky flat-spectrum sample. 2. New optical spectra and redshift measurements",

abstract = "We present optical spectra and redshift measurements for 178 flat-spectrum objects from the Parkes quarter-Jansky flat-spectrum sample. These spectra were obtained in order to compile a complete sample of quasars for use in a study of quasar evolution. We present a composite optical spectrum made from the subset of 109 quasars that have flux densities in the range 0.25 Jy < S2.7 GHz < 0.5 Jy, and make a comparison with a composite for radio-quiet QSOs from the Large Bright Quasar Survey. Our large sample of radio-loud quasars allows us to strengthen previous reports that the Lyα and CIV emission lines have larger equivalent width in radio-loud quasars than radio-quiet QSOs to greater than the 3σ level. However we see no significant difference in the equivalent widths of CIII] or MgII. We also show that the flux decrements across the Lyman-α line (DA) measured from these spectra show the same trend with redshift as for optically selected QSOs.",

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author = "Hook, {I. M.} and Shaver, {P. A.} and Jackson, {C. A.} and Wall, {J. V.} and Kellermann, {K. I.}",

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doi = "10.1051/0004-6361:20021803",

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T1 - The parkes quarter-Jansky flat-spectrum sample. 2. New optical spectra and redshift measurements

AU - Hook, I. M.

AU - Shaver, P. A.

AU - Jackson, C. A.

AU - Wall, J. V.

AU - Kellermann, K. I.

PY - 2003

Y1 - 2003

N2 - We present optical spectra and redshift measurements for 178 flat-spectrum objects from the Parkes quarter-Jansky flat-spectrum sample. These spectra were obtained in order to compile a complete sample of quasars for use in a study of quasar evolution. We present a composite optical spectrum made from the subset of 109 quasars that have flux densities in the range 0.25 Jy < S2.7 GHz < 0.5 Jy, and make a comparison with a composite for radio-quiet QSOs from the Large Bright Quasar Survey. Our large sample of radio-loud quasars allows us to strengthen previous reports that the Lyα and CIV emission lines have larger equivalent width in radio-loud quasars than radio-quiet QSOs to greater than the 3σ level. However we see no significant difference in the equivalent widths of CIII] or MgII. We also show that the flux decrements across the Lyman-α line (DA) measured from these spectra show the same trend with redshift as for optically selected QSOs.

AB - We present optical spectra and redshift measurements for 178 flat-spectrum objects from the Parkes quarter-Jansky flat-spectrum sample. These spectra were obtained in order to compile a complete sample of quasars for use in a study of quasar evolution. We present a composite optical spectrum made from the subset of 109 quasars that have flux densities in the range 0.25 Jy < S2.7 GHz < 0.5 Jy, and make a comparison with a composite for radio-quiet QSOs from the Large Bright Quasar Survey. Our large sample of radio-loud quasars allows us to strengthen previous reports that the Lyα and CIV emission lines have larger equivalent width in radio-loud quasars than radio-quiet QSOs to greater than the 3σ level. However we see no significant difference in the equivalent widths of CIII] or MgII. We also show that the flux decrements across the Lyman-α line (DA) measured from these spectra show the same trend with redshift as for optically selected QSOs.

KW - Quasars: general

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U2 - 10.1051/0004-6361:20021803

DO - 10.1051/0004-6361:20021803

M3 - Article

SN - 0004-6361

VL - 399

SP - 469

EP - 487

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

IS - 2

ER -

The parkes quarter-Jansky flat-spectrum sample. 2. New optical spectra and redshift measurements

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