Volume 565, May 2014
|Number of page(s)||4|
|Published online||25 April 2014|
The molecular gas content of ULIRG type 2 quasars at z < 1⋆
1 Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
2 Centro de Astrobiología (INTA-CSIC), Carretera de Ajalvir, km 4, 28850 Torrejón de Ardoz, Madrid, Spain
3 Centro de Astrofisica, Universidade do Porto, rua das Estrelas, 4150-762 Porto, Portugal
4 Dept. of Earth and Space Science, Onsala Space Observatory, Chalmers U. of Technology, 43992 Onsala, Sweden
5 Observatorio Astronómico Nacional (OAN)-Observatorio de Madrid, Alfonso XII, 3, 28014 Madrid, Spain
Received: 7 November 2013
Accepted: 26 February 2014
We present new results of CO(1–0) spectroscopic observations of four Sloan Digital Sky Survey (SDSS) type 2 quasars (QSO2) at z ~ 0.3, observed with the 30-m IRAM radio telescope. The QSO2 have infrared luminosities in the ultra-luminous infrared galaxies (ULIRG) regime. We confirm the CO(1–0) detection in one of our four QSO2, SDSS J1543-00, with L′CO and MH2 (1.2 ± 0.2) × 1010 K km s-1 pc2 and (9.4 ± 1.4) × 109 M ⊙, respectively. The full width at half maximum (FWHM) of the CO(1–0) line is =575 ± 102 km s-1. No CO(1–0) emission is detected in SDSS J0903+02, SDSS J1337-01, SDSS J1520-01 above 3 sigma, yielding upper limits on M(H2) ~ 9.6, 4.3 and 5.1 × 109 M⊙, respectively. We expand previous studies of the molecular gas content of intermediate z QSO2 into the ULIRG regime. Taking into account nine QSO2 at z ~ 0.3–1.0 from the literature, we discuss the location of the 13 ULIRG QSO2 at z < 1 with available L′CO measurements in the L′CO vs. z and L′CO vs. LFIR diagrams, in comparison with other QSO1 and ULIRG star forming samples.
Key words: quasars: general / quasars: emission lines / galaxies: ISM
© ESO, 2014
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