133 research outputs found
Interpreting physical and mental metaphors: Is Theory of Mind associated with pragmatics in middle childhood?
We investigated the association between individual differences in metaphor understanding and Theory of Mind (ToM) in typically developing children. We distinguished between two types of metaphors and created a Physical and Mental Metaphors task, echoing a similar distinction for ToM. Nine-year-olds scored lower than older age-groups in ToM as well as in the interpretation of mental, but not physical, metaphors. Moreover, nine-year-olds (but not older children) who are better in ToM are also better in interpreting mental, but not physical, metaphors. This suggests that the link between metaphor and ToM is stronger when metaphorical interpretation involves mental aspects, and it is more evident in early rather than later childhood
The vegetation of a mountain area of the Scalve Valley (Southern Alps) twenty years after environmental restoration work
The restoration of highly natural areas, such as mountain territories, is a very important issue for those involved in land management and nature conservation. This study reports data provided by the analysis of the vegetation of an area of the Scalve Valley (Lombardy, Italy) which underwent environmental restoration and soil stabilization work using soil bioengineering techniques following a landslide that occurred in 1992. Data on the vegetation, acquired by performing several phytosociological relev\ue9s (inside and outside the area) according to the Braun-Blanquet method (1964), were used to analyze the floristic and ecological characteristics of the plant communities currently present in the area. The Ecological Index of Maturity (EIM) (Giupponi et al. 2015) was applied in order to assess the level of disturbance to which the various plant communities are currently subject. The EIM is the result of the elaboration of flora and vegetation indices proposed by Taffetani & Rismondo (2009) and Rismondo et al. (2011) for the evaluation of the functionality of agro-ecosystems, and provides values ranging from 0 (high disturbance of vegetation) to 9 (undisturbed vegetation).
Results showed that, in the study area, there are some plant communities typical of forest margins, some typical of less evolved soils, and others with a high proportion of exotic species that were introduced in 1995 (at the end of slope stabilization work), when a mixture of commercial seed was sown. The results obtained calculating the EIM showed the presence of high disturbance for the plant communities with high percentages of exotic species and for those on unstable soils
The WISSH Quasars Project III. X-ray properties of hyper-luminous quasars
We perform a survey of the X-ray properties of 41 objects from the WISE/SDSS
selected Hyper-luminous (WISSH) quasars sample, composed by 86 broad-line
quasars (QSOs) with bolometric luminosity , at z~2-4. All but 3 QSOs show unabsorbed 2-10 keV luminosities
. Thanks to their extreme radiative output
across the Mid-IR-to-X-ray range, WISSH QSOs offer the opportunity to
significantly extend and validate the existing relations involving .
We study as a function of (i) X-ray-to-Optical (X/O) flux ratio,
(ii) mid-IR luminosity (), (iii) as well as (iv)
vs. the 2500 luminosity. We find that WISSH QSOs
show very low X/O(<0.1) compared to typical AGN values;
ratios significantly smaller than those derived for AGN with lower luminosity;
large X-ray bolometric corrections 100-1000; and steep
. These results lead to a scenario where the X-ray
emission of hyper-luminous quasars is relatively weaker compared to
lower-luminosity AGN. Models predict that such an X-ray weakness can be
relevant for the acceleration of powerful high-ionization emission line-driven
winds, commonly detected in the UV spectra of WISSH QSOs, which can in turn
perturb the X-ray corona and weaken its emission. Accordingly, hyper-luminous
QSOs represent the ideal laboratory to study the link between the AGN energy
output and wind acceleration. Additionally, WISSH QSOs show very large BH
masses (>9.5). This enables a more robust modeling
of the relation by increasing the statistics at high masses. We
derive a flatter dependence than previously found over the broad range
5 < < 11.Comment: 20 pages, 14 Figures. Accepted for publication on A&
The dense molecular gas in the QSO SDSS J231038.88+185519.7 resolved by ALMA
We present ALMA observations of the CO(6-5) and [CII] emission lines and the
sub-millimeter continuum of the quasi-stellar object (QSO) SDSS
J231038.88+185519.7. Compared to previous studies, we have analyzed a synthetic
beam that is ten times smaller in angular size, we have achieved ten times
better sensitivity in the CO(6-5) line, and two and half times better
sensitivity in the [CII] line, enabling us to resolve the molecular gas
emission. We obtain a size of the dense molecular gas of kpc, and
of kpc for the 91.5 GHz dust continuum. By assuming that CO(6-5) is
thermalized, and by adopting a CO--to-- conversion factor , we infer a molecular gas mass of
. Assuming that the
observed CO velocity gradient is due to an inclined rotating disk, we derive a
dynamical mass of , which is a factor of approximately two smaller than the previously
reported estimate based on [CII]. Regarding the central black hole, we provide
a new estimate of the black hole mass based on the C~IV emission line detected
in the X-SHOOTER/VLT spectrum: . We find a molecular gas fraction of ,
where . We derive a ratio
suggesting high gas turbulence, outflows/inflows
and/or complex kinematics due to a merger event. We estimate a global Toomre
parameter , indicating likely cloud fragmentation. We compare,
at the same angular resolution, the CO(6-5) and [CII] distributions, finding
that dense molecular gas is more centrally concentrated with respect to [CII].
We find that the current BH growth rate is similar to that of its host galaxy.Comment: A&A in pres
The WISSH quasars Project: II. Giant star nurseries in hyper-luminous quasars
Studying the coupling between the energy output produced by the central
quasar and the host galaxy is fundamental to fully understand galaxy evolution.
Quasar feedback is indeed supposed to dramatically affect the galaxy properties
by depositing large amounts of energy and momentum into the ISM. In order to
gain further insights on this process, we study the SEDs of sources at the
brightest end of the quasar luminosity function, for which the feedback
mechanism is supposed to be at its maximum. We model the rest-frame UV-to-FIR
SEDs of 16 WISE-SDSS Selected Hyper-luminous (WISSH) quasars at 1.8 < z < 4.6
disentangling the different emission components and deriving physical
parameters of both the nuclear component and the host galaxy. We also use a
radiative transfer code to account for the contribution of the quasar-related
emission to the FIR fluxes. Most SEDs are well described by a standard
combination of accretion disk+torus and cold dust emission. However, about 30%
of them require an additional emission component in the NIR, with temperatures
peaking at 750K, which indicates the presence of a hotter dust component in
these powerful quasars. We measure extreme values of both AGN bolometric
luminosity (LBOL > 10^47 erg/s) and SFR (up to 2000 Msun/yr). A new relation
between quasar and star-formation luminosity is derived (LSF propto
LQSO^(0.73)) by combining several Herschel-detected quasar samples from z=0 to
4. Future observations will be crucial to measure the molecular gas content in
these systems, probe the impact between quasar-driven outflows and on-going
star-formation, and reveal the presence of merger signatures in their host
galaxies.Comment: 19 pages, 12 figures; Accepted for publication in Astronomy &
Astrophysics on June 13, 201
The WISSH Project: Winds in the BLR
(On behalf of the WISSH collaboration) The WISE/SDSS-selected hyper-luminous quasar (WISSH) survey is an extensive multi-band observing program to investigate the role of nuclear activity in SMBH-galaxy self-regulated growth via extended outflows. Our ongoing project is designed to accurately probe the relationship between nuclear and host galaxy ISM properties in a large sample of ~90 quasars at the brightest end of the AGN luminosity function (log LBol > 47.3) and at the peak of their number density (z~2.5-3.5)We will report on the discovery of highly accreting (0.3-3Ledd), ten billion solar masses SMBHs being able to produce very powerful (up to ~ 4% of L_bol) ionized outflows and accretion disk windsThe impact of AGN-driven feedback on their host galaxies will be also discussed
The black hole and host galaxy growth in an isolated QSO observed with ALMA
The outstanding mass growth of supermassive black holes (SMBHs) at the
Reionisation Epoch and how it is related to the concurrent growth of their host
galaxies, poses challenges to theoretical models aimed at explaining how these
systems formed in short timescales (<1 Gyr). To trace the average evolutionary
paths of quasi-stellar objects (QSOs) and their host galaxies in the BH
mass-host mass () plane, we compare the star formation rate (SFR),
derived from the accurate estimate of the dust temperature and the dust mass
(), with the BH accretion rate. To this aim, we
analysed a deep, pc resolution ALMA observation of the sub-mm continuum,
[CII] and HO of the QSO J2310+1855, enabling a detailed study of
dust properties and cold gas kinematics. We performed an accurate SED analysis
obtaining a dust temperature of K and a dust mass of
. The implied AGN-corrected SFR
is , a factor of 2 smaller than previously
reported for this QSO. We derived the best estimate of the dynamical mass
within kpc, based on
a dynamical model of the system. We found that , suggesting that AGN feedback might be efficiently
acting to slow down the SMBH accretion, while the stellar mass assembly is
still vigorously taking place in the host galaxy. In addition, we were also
able to detect high-velocity emission on the red and blue sides of the [CII]
emission line, that traces a gaseous outflow, and for the first time, we mapped
a spatially-resolved water vapour disk through the HO v=0
emission line detected at GHz,
whose kinematic properties and size are broadly consistent with those of the
[CII] disk.Comment: 15 pages, 10 figures, 4 tables. Accepted in A&
Black hole and host galaxy growth in an isolated z 6 QSO observed with ALMA
The outstanding mass growth of supermassive black holes (SMBHs) at the epoch of reionisation and its relation to the concurrent growth of their host galaxies poses challenges to theoretical models aimed at explaining how these systems formed on short timescales (< 1 Gyr). To trace the average evolutionary paths of quasi-stellar objects (QSOs) and their host galaxies in the plane of BH mass to host mass (Mdyn), we compare the star formation rate (SFR), derived from the accurate estimate of the dust temperature and the dust mass (Tdust, Mdust) based on infrared and sub-millimeter (sub-mm) spectral energy distribution (SED), with the BH accretion rate, derived from Lbol based on X-ray and optical and ultraviolet SED. To this aim, we analysed a deep ALMA observation of the sub-mm continuum, [CII], and H2O of the z ∼ 6 QSO J2310+1855 with a resolution of 900 pc, which enabled a detailed study of dust properties and cold gas kinematics. We performed an accurate SED analysis obtaining a dust temperature of Tdust = 71 ± 4 K, dust mass Mdust = (4.4 ± 0.7)×108 M⊙, and total far-infrared luminosity of LTIR = 2.5−0.5+0.6 × 1013 L⊙. The implied active galactic nuclei (AGN) – corrected SFR = 1240−260+310 M⊙ yr−1 is a factor of 2 lower than previously reported for this QSO. We measured a gas-to-dust ratio of GDR = 101 ± 20. The dust continuum and [CII] surface brightness profiles are spatially extended out to r ∼ 6.7 kpc and r ∼ 5 kpc, respectively, with half-light radii of 0.9 and 1.1 kpc for the dust and gas, respectively. The derived gas surface density, Σgas, and star formation rate density, ΣSFR, place the J2310+1855 host galaxy above the Kennicutt-Schmidt relation. We derived a best estimate of the dynamical mass Mdyn = 5.2 × 1010 M⊙ within r = 1.7 kpc based on a dynamical model of the system with a rotating disk inclined at i = 25 deg. The Toomre parameter profile across the disk is Qgas ∼ 3 and implies that the disk is unstable. We found that SFR/Mdyn > ṀBH/MBH, suggesting that AGN feedback might be efficiently acting to slow down the SMBH accretion, while stellar mass assembly is still vigorously taking place in the host galaxy. In addition, we were also able to detect high-velocity emission on the red and blue sides of the [CII] emission line that is not consistent with disk rotation and traces a gaseous outflow. We derived an outflow mass Mout = 3.5 × 108 M⊙, and a mass outflow rate in the range Ṁout = 1800 − 4500 M⊙ yr−1. The implied Ėout ∼ 0.0005 − 0.001 Lbol is in agreement with the values observed for ionised winds. For the first time, we mapped a spatially resolved water vapour disk through the H2O v = 0 3(2, 2) − 3(1, 3) emission line detected at νobs = 274.074 GHz, whose kinematic properties and size are broadly consistent with those of the [CII] disk. The luminosity ratio LH2O/LTIR = 1.4 × 10−5 is consistent with line excitation by dust-reprocessed star formation in the interstellar medium of the host galaxy
The WISSH quasars project: VIII. Outflows and metals in the circum-galactic medium around the hyper-luminous z 3c 3.6 quasar J1538+08
Context. In recent years, Ly\u3b1 nebulae have been routinely detected around high redshift, radio-quiet quasars thanks to the advent of the highly sensitive integral field spectrographs. Constraining the physical properties of the Ly\u3b1 nebulae is crucial for a full understanding of the circum-galactic medium (CGM). The CGM acts both as a repository for intergalactic and galactic baryons as well as a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionising fluxes and dense CGM environments in which they are expected to be embedded. Aims. We aim to characterise the rest-frame ultraviolet (UV) emission lines in the CGM around a hyper-luminous, broad emission line, radio-quiet quasar at z 3c 3.6, which exhibits powerful outflows at both nuclear and host galaxy scales. Methods. We analyse VLT/MUSE observations of the quasar J1538+08 (Lbol = 6
7 1047 erg s-1), and we performed a search for extended UV emission lines to characterise its morphology, emissivity, kinematics, and metal content. Results. We report the discovery of a very luminous ( 3c2
7 1044 erg s-1), giant Ly\u3b1 nebula and a likely associated extended (75 kpc) CIV nebula. The Ly\u3b1 nebula emission exhibits moderate blueshift ( 3c440 km s-1) compared to the quasar systemic redshift and a large average velocity dispersion (\u3c3\u304v 3c700 km s-1) across the nebula, while the CIV nebula shows average velocity dispersion of \u3c3\u304v 3c350 km s-1. The Ly\u3b1 line profile exhibits a significant asymmetry towards negative velocity values at 20-30 kpc south of the quasar and is well parametrised by the following two Gaussian components: a narrow (\u3c3 3c 470 km s-1) systemic one plus a broad (\u3c3 3c 1200 km s-1), blueshifted ( 3c1500 km s-1) one. Conclusions. Our analysis of the MUSE observation of J1538+08 reveals metal-enriched CGM around this hyper-luminous quasar. Furthermore, our detection of blueshifted emission in the emission profile of the Ly\u3b1 nebula suggests that powerful nuclear outflows can propagate through the CGM over tens of kiloparsecs
On the discovery of fast molecular gas in the UFO/BAL quasar APM 08279+5255 at z = 3.912
We have performed a high sensitivity observation of the UFO/BAL quasar APM
08279+5255 at z=3.912 with NOEMA at 3.2 mm, aimed at detecting fast moving
molecular gas. We report the detection of blueshifted CO(4-3) with maximum
velocity (v95\%) of km s, with respect to the systemic peak
emission, and a luminosity of K km s
pc (where is the lensing magnification factor). We discuss various
scenarios for the nature of this emission, and conclude that this is the first
detection of fast molecular gas at redshift . We derive a mass flow rate of
molecular gas in the range M/yr, and
momentum boost , therefore consistent with
a momentum conserving flow. For the largest the scaling is also
consistent with a energy conserving flow with an efficiency of 10-20\%.
The present data can hardly discriminate between the two expansion modes. The
mass loading factor of the molecular outflow is .
We also detect a molecular emission line at a frequency of 94.83 GHz,
corresponding to a rest frame frequency of 465.8 GHz, which we tentatively
identified with the cation molecule (5-4), which would be the first
detection of this species at high redshift. We discuss the alternative
possibility that this emission is due to a CO emission line from the, so far
undetected, lens galaxy. Further observations of additional transitions of the
same species with NOEMA can discriminate between the two scenarios
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