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Register a new userThe impact of ionised outflows from z$sim$2.5 quasars is not through instantaneous in-situ quenching: the evidence from ALMA and VLT/SINFONI
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We present high-resolution ($sim$2.4,kpc) ALMA band 7 observations (rest-frame $lambda sim 250mu$m) of three powerful z$sim$2.5 quasars ($L_{rm bol}=10^{47.3}$-$10^{47.5}$ ergs s$^{-1}$). These targets have previously been reported as showing evidence for suppressed star formation based on cavities in the narrow H$alpha$ emission at the location of outflows traced with [O~{sc iii}] emission. Here we combine the ALMA observations with a re-analysis of the VLT/SINFONI data to map the rest-frame far-infrared emission, H$alpha$ emission, and [O~{sc iii}] emission. In all targets we observe high velocity [O~{sc iii}] gas (i.e., W80$sim$1000--2000,km,s$^{-1}$) across the whole galaxy. We do not identify any H$alpha$ emission that is free from contamination from AGN-related processes; however, based on SED analyses, we show that the ALMA data contains a significant dust-obscured star formation component in two out of the three systems. This dust emission is found to be extended over $approx$1.5--5.5,kpc in the nuclear regions, overlaps with the previously reported H$alpha$ cavities and is co-spatial with the peak in surface brightness of the [O~{sc iii}] outflows. In summary, within the resolution and sensitivity limits of the data, we do not see any evidence for a instantaneous shut down of in-situ star formation caused directly by the outflows. However, similar to the conclusions of previous studies and based on our measured star formation rates, we do not rule out that the global host galaxy star formation could be suppressed on longer timescales by the cumulative effect of quasar episodes during the growth of these massive black holes.
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The physical properties of galactic winds are of paramount importance for our understanding of galaxy formation. Fortunately, they can be constrained using background quasars passing near star-forming galaxies (SFGs). From the 14 quasar$-$galaxy pairs in our VLT/SINFONI Mgii Program for Line Emitters (SIMPLE) sample, we reobserved the 10 brightest galaxies in H$_{alpha}$ with the VLT/SINFONI with 0.7 seeing and the corresponding quasar with the VLT/UVES spectrograph. Applying geometrical arguments to these ten pairs, we find that four are likely probing galactic outflows, three are likely probing extended gaseous disks, and the remaining three are not classifiable because they are viewed face-on. In this paper we present a detailed comparison between the line-of-sight kinematics and the host galaxy emission kinematics for the pairs suitable for wind studies. We find that the kinematic profile shapes (asymmetries) can be well reproduced by a purely geometrical wind model with a constant wind speed, except for one pair (towards J2357$-$2736) that has the smallest impact parameter b = 6 kpc and requires an accelerated wind flow. Globally, the outflow speeds are $sim$ 100 km/s and the mass ejection rates (or $dot M _{rm out}$) in the gas traced by the low-ionization species are similar to the star formation rate (SFR), meaning that the mass loading factor, $eta$ = $dot M _{rm out}$/SFR, is $sim$1.0. The outflow speeds are also smaller than the local escape velocity, which implies that the outflows do not escape the galaxy halo and are likely to fall back into the interstellar medium.
We present VLT/SINFONI observations of 35 quasars at 2.1 < z < 3.2, the majority of which were selected from the Clusters Around Radio-Loud AGN (CARLA) survey. CARLA quasars have large CIV-based black hole (BH) masses (M(BH) > 10^9 Msun) and powerful radio emission (P(500MHz) > 27.5 W/Hz). We estimate Ha-based M(BH), finding a scatter of 0.35 dex compared to CIV. We evaluate several recipes for correcting CIV-based masses, which reduce the scatter to 0.24 dex. The radio power of the radio-loud quasars is at most weakly correlated with the interconnected quantities Ha-width, L(5100A) and M(BH), suggesting that it is governed by different physical processes. However, we do find a strong inverse correlation between CIV blueshift and radio power linked to higher Eddington ratios and L(5100A). Under standard assumptions, the BH growth time is longer than the cosmic age for many CARLA quasars, suggesting that they must have experienced more efficient growth in the past. If these BHs were growing from seeds since the epoch of reionization, it is possible that they grew at the Eddington limit like the quasars at z ~ 6-7, and then continued to grow at the reduced rates observed until z ~ 2-3. Finally, we study the relation between M(BH) and environment, finding a weak positive correlation between M(BH) and galaxy density measured by CARLA.
As part of our KMOS AGN Survey at High-redshift (KASHz), we present spatially-resolved VLT/KMOS and VLT/SINFONI spectroscopic data and ALMA 870$mu$m continuum imaging of eight $z$=1.4--2.6 moderate AGN ($L_{rm 2-10 rm kev}$ = $10^{42} - 10^{45}$ ergs s$^{-1}$). We map [OIII], H$alpha$ and rest-frame FIR emission to search for any spatial anti-correlation between ionised outflows (traced by the [OIII] line) and star formation (SF; traced by H$alpha$ and FIR), that has previously been claimed for some high-z AGN and used as evidence for negative and/or positive AGN feedback. Firstly, we conclude that H$alpha$ is unreliable to map SF inside our AGN host galaxies based on: (i) SF rates inferred from attenuation-corrected H$alpha$ can lie below those inferred from FIR; (ii) the FIR continuum is more compact than the H$alpha$ emission by a factor of $sim 2$ on average; (iii) in half of our sample, we observe significant spatial offsets between the FIR and H$alpha$ emission, with an average offset of $1.4pm0.6$ kpc. Secondly, for the five targets with outflows we find no evidence for a spatial anti-correlation between outflows and SF using either H$alpha$ or FIR as a tracer. This holds for our re-analysis of a famous $z$=1.6 X-ray AGN (`XID 2028) where positive and negative feedback has been previously claimed. Based on our results, any impact on SF by ionised outflows must be subtle, either occurring on scales below our resolution, or on long timescales.
We measure the evolution of the quiescent fraction and quenching efficiency of satellites around star-forming and quiescent central galaxies with stellar mass $log(M_{mathrm{cen}}/M_{odot})>10.5$ at $0.3<z<2.5$. We combine imaging from three deep near-infrared-selected surveys (ZFOURGE/CANDELS, UDS, and UltraVISTA), which allows us to select a stellar-mass complete sample of satellites with $log(M_{mathrm{sat}}/M_{odot})>9.3$. Satellites for both star-forming and quiescent central galaxies have higher quiescent fractions compared to field galaxies matched in stellar mass at all redshifts. We also observe galactic conformity: satellites around quiescent centrals are more likely to be quenched compared to the satellites around star-forming centrals. In our sample, this conformity signal is significant at $gtrsim3sigma$ for $0.6<z<1.6$, whereas it is only weakly significant at $0.3<z<0.6$ and $1.6<z<2.5$. Therefore, conformity (and therefore satellite quenching) has been present for a significant fraction of the age of the universe. The satellite quenching efficiency increases with increasing stellar mass of the central, but does not appear to depend on the stellar mass of the satellite to the mass limit of our sample. When we compare the satellite quenching efficiency of star-forming centrals with stellar masses 0.2 dex higher than quiescent centrals (which should account for any difference in halo mass), the conformity signal decreases, but remains statistically significant at $0.6<z<0.9$. This is evidence that satellite quenching is connected to the star-formation properties of the central as well as to the mass of the halo. We discuss physical effects that may contribute to galactic conformity, and emphasize that they must allow for continued star-formation in the central galaxy even as the satellites are quenched.
Theoretical models have suggested an evolutionary model for quasars, in which most of luminous quasars are triggered by major mergers. It is also postulated that reddening as well as powerful outflows indicate an early phase of activity, close to the merger event. We test this model on a sample of quasars with powerful low ionization outflows seen in broad Iron absorption lines (FeLoBAL). This sample of objects show strong reddening in the optical and fast ($sim$0.1c) high column density outflows. We present HST WFC3/IR F160W imaging of 10 FeLoBAL host galaxies at redshifts z$sim$0.9 ($lambda_{rest}sim8500AA$). We compare the host galaxy morphologies and merger signatures of FeLoBALs to luminous blue non-BAL quasars from Villforth et al. 2017 of comparable luminosity, which show no excess of merger features compared to inactive control samples. If FeLoBAL quasars are indeed in a young evolutionary state, close in time to the initial merging event, they should have strong merger features. We find that the host galaxies of FeLoBAL quasars are of comparable luminosity to the host galaxies of optical quasars and show no enhanced merger rates. When looking only at quasars without strong PSF residuals, an enhancement in disturbed and merger rates is seen. While FeLoBAL hosts show weak enhancements over a control of blue quasars, their host galaxies are not dominated by recent major mergers.
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