Disk, merger, or outflow? Molecular gas kinematics in two powerful obscured QSOs at z >= 3.4

作者：Polletta M^*; Nesvadba N P H; Neri R; Omont A; Berta S; Bergeron J

来源：Astronomy & Astrophysics, 2011, 533: A20.

DOI：10.1051/0004-6361/201116446

• galaxies: high-redshift
• galaxies: active
• submillimeter: galaxies
• submillimeter: ISM
• quasars: general
• galaxies: evolution

We report on the detection of bright CO(4-3) line emission in two powerful, obscured quasars discovered in the SWIRE survey, SW022513 and SW022550 at z >= 3.4. We analyze the line strength and profile to determine the gas mass, dynamical mass, and the gas dynamics for both galaxies. In SW022513 we may have found the first evidence for a molecular, AGN-driven wind in the early Universe. The line profile in SW022513 is broad (FWHM = 1000 km s(-1)) and blueshifted by -200 km s(-1) relative to systemic (where the systemic velocity is estimated from the narrow components of ionized gas lines, as is commonly done for AGN at low and high redshifts). SW022550 has a more regular, double-peaked profile, which is marginally spatially resolved in our data, consistent with either a merger or an extended disk.
The molecular gas masses, 4 x 10(10) M-circle dot, are large and account for <30% of the stellar mass, making these obscured QSOs as gas rich as other powerful CO emitting galaxies at high redshift, i.e., submillimeter galaxies. Our sources exhibit relatively lower star-formation efficiencies compared to other dusty, powerful starburst galaxies at high redshift. We speculate that this could be a consequence of the AGN perturbing the molecular gas.

• 出版日期2011-9