The molecular gas content of ULIRG type 2 quasars at z < 1 (Research Note)

Artikel i vetenskaplig tidskrift, 2014

We present new results of CO(1-0) spectroscopic observations of four Sloan Digital Sky Survey (SDSS) type 2 quasars (QSO2) at z similar to 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 M-H2 (1.2 +/- 0.2) x 10(10) K km s(-1) pc(2) and (9.4 +/- 1.4) x 10(9) M-circle dot, 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(H-2) similar to 9.6, 4.3 and 5.1 x 10(9) M-circle dot, 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 similar to 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. L-FIR diagrams, in comparison with other QSO1. and ULIRG star forming samples.