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Abstract High-velocity outflows are ubiquitous in compact, massive (M*∼ 1011M⊙),z∼ 0.5 galaxies with extreme star formation surface densities (ΣSFR∼ 2000M⊙yr−1kpc−2). We have previously detected and characterized these outflows using Mgiiabsorption lines. To probe their full extent, we present Keck/KCWI integral field spectroscopy of the [Oii] and Mgiiemission nebulae surrounding all of the 12 galaxies in this study. We find that [Oii] is more effective than Mgiiin tracing low surface brightness, extended emission in these galaxies. The [Oii] nebulae are spatially extended beyond the stars, with radial extentR90between 10 and 40 kpc. The nebulae exhibit nongravitational motions, indicating galactic outflows with maximum blueshifted velocities ranging from −335 to −1920 km s−1. The outflow kinematics correlate with the bursty star formation histories of these galaxies. Galaxies with the most recent bursts of star formation (within the last <3 Myr) exhibit the highest central velocity dispersions (σ≳ 400 km s−1), while the oldest bursts have the lowest-velocity outflows. Many galaxies exhibit both high-velocity cores and more extended, slower-moving gas indicative of multiple outflow episodes. The slower, larger outflows occurred earlier and have decelerated as they propagate into the circumgalactic medium and mix on timescales ≳50 Myr.
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Evidence for Intrinsic X-Ray Weakness among Red Quasars at Cosmic Noon
Abstract Quasar feedback is a key ingredient in shaping galaxy evolution. A rare population of extremely red quasars (ERQs) atz= 2−3 are often associated with high-velocity [Oiii]λ5008 outflows and may represent sites of strong feedback. In this paper, we present an X-ray study of 50 ERQs to investigate the link between the X-ray and outflow properties of these intriguing objects. Using hardness ratio analysis, we confirm that the ERQs are heavily obscured systems with gas column density reachingNH= 1023−24cm−2. We identify 20 X-ray-nondetected ERQs at high mid-infrared (MIR) luminosities ofνLν,6μm≳ 3 × 1046erg s−1. By stacking the X-ray observations, we find that the nondetected ERQs are on average underluminous in X-rays by a factor of ∼10 for their MIR luminosities. We consider such X-ray weakness to be due to both heavy gas absorption and intrinsic factors. Moreover, we find that the X-ray-weak sources also display higher-velocity outflows. One option to explain this trend is that weaker X-rays facilitate more vigorous line-driven winds, which then accelerate the [Oiii]-emitting gas to kiloparsec scales. Alternatively, super-Eddington accretion could also lead to intrinsic X-ray weakness and more powerful continuum-driven outflow.
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- Award ID(s):
- 2106453
- PAR ID:
- 10548960
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 974
- Issue:
- 2
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 225
- Size(s):
- Article No. 225
- Sponsoring Org:
- National Science Foundation
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