Casey Carlile | Searcharxiv

arXiv2026

KCWI Observations of Type 2 Quasar-driven Ionized Outflows at z~0.1

AGN-driven outflows play a crucial role in regulating star formation in galaxies. These outflows are known to be multi-phase, and the characterization of the kinematics, extent, and energetics of each gas phase is needed to obtain a full picture of the outflow properties and impact. This study presents Keck Cosmic Web Imager (KCWI) integral field spectroscopy of the ionized gas outflow properties in seven low redshift (z<0.1) quasars---six Type 2 AGN and one narrow-line Type 1 AGN---providing insight into the warm ionized outflows in these luminous AGN. With the large field-of-view and high sensitivity of KCWI, these data reveal both larger ionized outflow extents than were previously known for these sources and uncover the existence of additional high-velocity kinematic components in the ionized outflows of these luminous AGN. We find (a) a high incidence (50-70%) of multiple outflows on scales of 4--10 kpc and (b) trends between the outflow extent, kinematics, and the ionized mass and energy outflow rates. These trends imply that the faster and often smaller outflows carry higher mass and energy outflow rates than the slower, larger outflows. We also find that the ionized gas outflows reach as far as the known extent of narrow-line ionized gas emission in AGN, which is known to depend weakly on AGN luminosity. This work highlights the utility of the current generation of wide-field integral field spectrographs on 8--10m class telescopes for studying quasar-driven outflows.

astro-ph.GA↗

arXiv2020

The Accretion History of AGN: A Newly Defined Population of Cold Quasars

Quasars are the most luminous of active galactic nuclei (AGN), and are perhaps responsible for quenching star formation in their hosts. The Stripe 82X catalog covers 31.3 deg$^2$ of the Stripe 82 field, of which the 15.6 deg$^2$ covered with XMM-Newton is also covered by Herschel/SPIRE. We have 2500 X-ray detected sources with multi-wavelength counterparts, and 30% of these are unobscured quasars, with $L_X > 10^{44}\,$erg/s and $M_B < -23$. We define a new population of quasars which are unobscured, have X-ray luminosities in excess of $10^{44}\,$erg/s, have broad emission lines, and yet are also bright in the far-infrared, with a 250$μ$m flux density of $S_{\rm 250}>30$mJy. We refer to these Herschel-detected, unobscured quasars as "Cold Quasars". A mere 4% (21) of the X-ray- and optically-selected unobscured quasars in Stripe 82X are detected at 250$μ$m. These Cold Quasars lie at $z\sim1-3$, have $L_{\rm IR}>10^{12}\,L_\odot$, and have star formation rates of $\sim200-1400\,M_\odot$/yr. Cold Quasars are bluer in the mid-IR than the full quasar population, and 72% of our Cold Quasars have WISE W3 $<$ 11.5 [Vega], while only 19% of the full quasar sample meets this criteria. Crucially, Cold Quasars have on average $\sim9\times$ as much star formation as the main sequence of star forming galaxies at similar redshifts. Although dust-rich, unobscured quasars have occasionally been noted in the literature before, we argue that they should be considered as a separate class of quasars due to their high star formation rates. This phase is likely short-lived, as the central engine and immense star formation consume the gas reservoir. Cold Quasars are type-1 blue quasars that reside in starburst galaxies.

astro-ph.GA↗