| 1. |
- Lamperti, I., et al.
(author)
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SUPER: V. ALMA continuum observations of z ∼2 AGN and the elusive evidence of outflows influencing star formation
- 2021
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 654
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Journal article (peer-reviewed)abstract
- We study the impact of active galactic nuclei (AGN) ionised outflows on star formation in high-redshift AGN host galaxies, by combining near-infrared integral field spectroscopic (IFS) observations, mapping the H emission and [O iii]5007 outflows, with matched-resolution observations of the rest-frame far-infrared (FIR) emission.We present high-resolution ALMA Band 7 observations of eight X-ray selected AGN (L2-10 keV = 1043:81045:2 erg s1) at z 2 from the SUPER (SINFONI Survey for Unveiling the Physics and Eect of Radiative feedback) sample, targeting the observed-frame 870 m (rest-frame 260 m) continuum at 2 kpc (0.200) spatial resolution. The targets were selected among the SUPER AGN with an [O iii] detection in the IFS maps and with a detection in the FIR photometry. We detected six out of eight targets with signal-to-noise ratio S=N & 10 in the ALMA maps, from which we measured continuum flux densities in the range 0:272:58 mJy and FIR half-light radii (Re) in the range 0:8-2:1 kpc. The other two targets were detected with S/N of 3.6 and 5.9, which are insucient for spatially resolved analysis. The FIR Re of our sample are comparable to other AGN and star-forming galaxies at a similar redshift from the literature. However, combining our sample with the literature samples, we find that the mean FIR size in X-ray AGN (Re = 1:16 0:11 kpc) is slightly smaller than in non-AGN (Re = 1:69 0:13 kpc). From spectral energy distribution fitting, we find that the main contribution to the 260 m flux density is dust heated by star formation, with 4% contribution from AGN-heated dust and 1% from synchrotron emission. The majority of our sample show dierent morphologies for the FIR (mostly due to reprocessed stellar emission) and the ionised gas emission (H and [O iii], mostly due to AGN emission). This could be due to the dierent locations of dust and ionised gas, the dierent sources of the emission (stars and AGN), or the eect of dust obscuration.We are unable to identify any residual H emission, above that dominated by AGN, that could be attributed to star formation. Under the assumption that the FIR emission is a reliable tracer of obscured star formation, we find that the obscured star formation activity in these AGN host galaxies is not clearly aected by the ionised outflows. However, we cannot rule out that star formation suppression is happening on smaller spatial scales than the ones we probe with our observations (<2 kpc) or on dierent timescales.
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| 2. |
- Scholtz, Jan, 1992, et al.
(author)
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The impact of ionized outflows from z - 2.5 quasars is not through instantaneous in situ quenching: The evidence from ALMA and VLT/SINFONI
- 2021
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In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 505:4, s. 5469-5487
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Journal article (peer-reviewed)abstract
- We present high-resolution (-2.4 kpc) ALMA band 7 observations (rest-frame λ - 250 μm) of three powerful z - 2.5 quasars (Lbol = 1047.3–1047.5 erg s−1). These targets have previously been reported as showing evidence for suppressed star formation based on cavities in the narrow H α emission at the location of outflows traced with [O 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 α emission, and [O III] emission. In all targets, we observe high velocity [O III] gas (i.e. W80 - 1000–2000 km s−1) across the whole galaxy. We do not identify any H α emission that is free from contamination from AGN-related processes; however, based on SED analyses, we show that the ALMA data contain a significant dust-obscured star formation component in two out of the three systems. This dust emission is found to be extended over ≈1.5–5.5 kpc in the nuclear regions, overlaps with the previously reported H α cavities and is co-spatial with the peak in surface brightness of the [O 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 time-scales by the cumulative effect of quasar episodes during the growth of these massive black holes.
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| 3. |
- Cicone, C., et al.
(author)
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SUPER VI. A giant molecular halo around a z similar to 2 quasar
- 2021
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 654
-
Journal article (peer-reviewed)abstract
- We present the discovery of copious molecular gas in the halo of cid_346, a z=2.2 quasar studied as part of the SINFONI survey for Unveiling the Physics and Effect of Radiative feedback (SUPER). New Atacama Compact Array (ACA) CO(3-2) observations detect a much higher flux (by a factor of 14 +/- 5) than measured on kiloparsec scales (r less than or similar to 8 kpc) using previous snapshot Atacama Large Millimeter/submillimeter Array data. Such additional CO(3-2) emission traces a structure that extends out to r similar to 200 kpc in projected size, as inferred through direct imaging and confirmed by an analysis of the uv visibilities. This is the most extended molecular circumgalactic medium (CGM) reservoir that has ever been mapped. It shows complex kinematics, with an overall broad line profile (FWHM=1000 km s(-1)) that is skewed towards redshifted velocities up to at least v similar to 1000 km s(-1). Using the optically thin assumption, we estimate a strict lower limit for the total molecular CGM mass observed by ACA of M-mol(CGM) > 10(10) M-circle dot. There is however room for up to M-mol(CGM) similar to 1.7 x 10(12) M-circle dot, once optically thick CO emission with alpha(CO) = 3.6 M-circle dot (K km s(-1) pc(2))(-1) and LCO(3- 2)'/LCO(1-0)' = 0.5 are assumed. Since cid_346 hosts quasar-driven ionised outflows and since there is no evidence of merging companions or an overdensity, we suggest that outflows may have played a crucial rule in seeding metal-enriched, dense gas on halo scales. However, the origin of such an extended molecular CGM remains unclear.
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