294 research outputs found
The Myth of the Stupid Believer: The Negative Religiousness–IQ Nexus is Not on General Intelligence (g) and is Likely a Product of the Relations Between IQ and Autism Spectrum Traits
Numerous studies have found a negative relationship between religiousness and IQ.
It is in the region of −0.2, according to meta-analyses. The reasons for this relationship are, however, unknown. It has been suggested that higher intelligence leads
to greater attraction to science, or that it helps to override evolved cognitive dispositions such as for religiousness. Either way, such explanations assume that the
religion–IQ nexus is on general intelligence (g), rather than some subset of specialized cognitive abilities. In other words, they assume it is a Jensen efect. Two large
datasets comparing groups with diferent levels of religiousness show that their IQ
diferences are not on g and must, therefore, be attributed to specialized abilities. An
analysis of the specialized abilities on which the religious and non-religious groups
difer reveals no clear pattern. We cautiously suggest that this may be explicable in
terms of autism spectrum disorder traits among people with high IQ scores, because
such traits are negatively associated with religiousness
Stars and dark matter in the spiral gravitational lens 2237+0305
We construct a mass model for the spiral lens galaxy 2237+0305, at redshift
z_l=0.04, based on gravitational-lensing constraints, HI rotation, and new
stellar-kinematic information, based on data taken with the ESI spectrograph on
the 10m Keck-II Telescope. High resolution rotation curves and velocity
dispersion profiles along two perpendicular directions, close to the major and
minor axes of the lens galaxy, were obtained by fitting the Mgb-Fe absorption
line region. The stellar rotation curve rises slowly and flattens at r~1.5"
(~1.1 kpc). The velocity dispersion profile is approximately flat. A
combination of photometric, kinematic and lensing information is used to
construct a mass model for the four major mass components of the system -- the
dark matter halo, disc, bulge, and bar. The best-fitting solution has a dark
matter halo with a logarithmic inner density slope of gamma=0.9+/-0.3 for
rho_DM propto r^-gamma, a bulge with M/L_B=6.6+/-0.3 Upsilon_odot, and a disc
with M/L_B =1.2+/-0.3 Upsilon_odot, in agreement with measurements of late-type
spirals. The bulge dominates support in the inner regions where the multiple
images are located and is therefore tightly constrained by the observations.
The disc is sub-maximal and contributes 45+/-11 per cent of the rotational
support of the galaxy at 2.2r_d. The halo mass is (2.0+/-0.6) x 10^12 M_odot,
and the stellar to virial mass ratio is 7.0+/-2.3 per cent, consistent with
typical galaxies of the same mass.Comment: 14 pages, 6 figures, MNRAS, in pres
Disentangling Baryons and Dark Matter in the Spiral Gravitational Lens B1933+503
Measuring the relative mass contributions of luminous and dark matter in
spiral galaxies is important for understanding their formation and evolution.
The combination of a galaxy rotation curve and strong lensing is a powerful way
to break the disk-halo degeneracy that is inherent in each of the methods
individually. We present an analysis of the 10-image radio spiral lens
B1933+503 at z_l=0.755, incorporating (1) new global VLBI observations, (2) new
adaptive-optics assisted K-band imaging, (3) new spectroscopic observations for
the lens galaxy rotation curve and the source redshift. We construct a
three-dimensionally axisymmetric mass distribution with 3 components: an
exponential profile for the disk, a point mass for the bulge, and an NFW
profile for the halo. The mass model is simultaneously fitted to the kinematics
and the lensing data. The NFW halo needs to be oblate with a flattening of
a/c=0.33^{+0.07}_{-0.05} to be consistent with the radio data. This suggests
that baryons are effective at making the halos oblate near the center. The
lensing and kinematics analysis probe the inner ~10 kpc of the galaxy, and we
obtain a lower limit on the halo scale radius of 16 kpc (95% CI). The dark
matter mass fraction inside a sphere with a radius of 2.2 disk scale lengths is
f_{DM,2.2}=0.43^{+0.10}_{-0.09}. The contribution of the disk to the total
circular velocity at 2.2 disk scale lengths is 0.76^{+0.05}_{-0.06}, suggesting
that the disk is marginally submaximal. The stellar mass of the disk from our
modeling is log_{10}(M_{*}/M_{sun}) = 11.06^{+0.09}_{-0.11} assuming that the
cold gas contributes ~20% to the total disk mass. In comparison to the stellar
masses estimated from stellar population synthesis models, the stellar initial
mass function of Chabrier is preferred to that of Salpeter by a probability
factor of 7.2.Comment: 16 pages, 13 figures, minor revisions based on referee's comments,
accepted for publication in Ap
Mass Modeling of Disk Galaxies: Constraints, Degeneracies and Adiabatic Contraction
This paper addresses available constraints on mass models fitted to rotation
curves. Mass models of disk galaxies have well-known degeneracies, that prevent
a unique mass decomposition. The most notable is due to the unknown value of
the stellar mass-to-light ratio (the disk-halo degeneracy); even with this
known, degeneracies between the halo parameters themselves may prevent an
unambiguous determination of the shape of the dark halo profile, which includes
the inner density slope of the dark matter halo. The latter is often referred
to as the ``cusp-core degeneracy''. We explore constraints on the disk and halo
parameters and apply these to four mock and six observed disk galaxies with
high resolution and extended rotation curves. Our full set of constraints
consists of mass-to-light (M/L) ratios from stellar population synthesis models
based on B-R colors, constraints on halo parameters from N-body simulations,
and constraining the halo virial velocity to be less than the maximum observed
velocity. These constraints are only partially successful in lifting the
cusp-core degeneracy. The effect of adiabatic contraction of the halo by the
disk is to steepen cores into cusps and reduce the best-fit halo concentration
and M/L values (often significantly). We also discuss the effect of disk
thickness, halo flattening, distance errors, and rotation curve error values on
mass modeling. Increasing the imposed minimum rotation curve error from
typically low, underestimated values to more realistic estimates decreases the
chi-square substantially and makes distinguishing between a cuspy or cored halo
profile even more difficult. In spite of the degeneracies and uncertainties
present, our constrained mass modeling favors sub-maximal disks (i.e., a
dominant halo) at 2.2 disk scale lengths, with Vdisk/Vtot < 0.6.Comment: 26 pages, 11 figures, minor changes to agree with published version,
uses emulateap
Two-dimensional kinematics of SLACS lenses: III. Mass structure and dynamics of early-type lens galaxies beyond z ~ 0.1
We combine in a self-consistent way the constraints from both gravitational
lensing and stellar kinematics to perform a detailed investigation of the
internal mass distribution, amount of dark matter, and dynamical structure of
the 16 early-type lens galaxies from the SLACS Survey, at z = 0.08 - 0.33, for
which both HST/ACS and NICMOS high-resolution imaging and VLT VIMOS IFU
spectroscopy are available. Based on this data set, we analyze the inner
regions of the galaxies, i.e. typically within one (3D) effective radius r_e,
under the assumption of axial symmetry and by constructing dynamical models
supported by two-integral stellar DFs. For all systems, the total mass density
distribution is found to be well approximated by a simple power-law: this
profile is on average slightly super-isothermal, with a logarithmic slope
= 2.074^{+0.043}_{-0.041} (68% CL) and an intrinsic scatter
0.144^{+0.055}_{-0.014}, and is fairly round, with an average axial ratio =
0.77+/-0.04. The lower limit for the dark matter fraction (fDM) inside r_e
ranges, in individual systems, from nearly zero to almost a half, with a median
value of 12%. By including stellar masses derived from SPS models with a
Salpeter IMF, we obtain an average fDM = 31%. The fDM rises to 61% if, instead,
a Chabrier IMF is assumed. For both IMFs, the dark matter fraction increases
with the total mass of the galaxy (3-sigma correlation). Based on the intrinsic
angular momentum parameter calculated from our models, we find that the
galaxies can be divided into two dynamically distinct groups, which are shown
to correspond to the usual classes of the slow and fast rotators. Overall, the
SLACS systems are structurally and dynamically very similar to their nearby
counterparts, indicating that the inner regions of early-type galaxies have
undergone little, if any, evolution since redshift z ~ 0.35. (Abridged)Comment: 27 pages, 34 figures. MNRAS, in pres
Constraints on the Assembly and Dynamics of Galaxies: I. Detailed Rest-frame Optical Morphologies on Kiloparsec-scale of z ~ 2 Star-forming Galaxies
We present deep and high-resolution HST/NIC2 F160W imaging at 1.6micron of
six z~2 star-forming galaxies with existing near-IR integral field spectroscopy
from SINFONI at the VLT. The unique combination of rest-frame optical imaging
and nebular emission-line maps provides simultaneous insight into morphologies
and dynamical properties. The overall rest-frame optical emission of the
galaxies is characterized by shallow profiles in general (Sersic index n<1),
with median effective radii of ~5kpc. The morphologies are significantly clumpy
and irregular, which we quantify through a non-parametric morphological
approach, estimating the Gini (G), Multiplicity (Psi), and M_20 coefficients.
The strength of the rest-frame optical emission lines in the F160W bandpass
indicates that the observed structure is not dominated by the morphology of
line-emitting gas, and must reflect the underlying stellar mass distribution of
the galaxies. The sizes and structural parameters in the rest-frame optical
continuum and Halpha emission reveal no significant differences, suggesting
similar global distributions of the on-going star formation and more evolved
stellar population. While no strong correlations are observed between stellar
population parameters and morphology within the NIC2/SINFONI sample itself, a
consideration of the sample in the context of a broader range of z~2 galaxy
types indicates that these galaxies probe the high specific star formation rate
and low stellar mass surface density part of the massive z~2 galaxy population,
with correspondingly large effective radii, low Sersic indices, low G, and high
Psi and M_20. The combined NIC2 and SINFONI dataset yields insights of
unprecedented detail into the nature of mass accretion at high redshift.
[Abridged]Comment: 44 pages, 19 figures. Revised version accepted for publication in the
Astrophysical Journa
Line-of-sight velocity dispersions and a mass distribution model of the Sa galaxy NGC 4594
In the present paper we develop an algorithm allowing to calculate
line-of-sight velocity dispersions in an axisymmetric galaxy outside of the
galactic plane. When constructing a self-consistent model, we take into account
the galactic surface brightness distribution, stellar rotation curve and
velocity dispersions. This algorithm is applied to a Sa galaxy NGC 4594 = M
104, for which there exist velocity dispersion measurements outside of the
galactic major axis. The mass distribution model is constructed in two stages.
In the first stage we construct a luminosity distribution model, where only
galactic surface brightness distribution is taken into account. Thereafter, in
the second stage we develop on the basis of the Jeans equations a detailed mass
distribution model and calculate line-of-sight velocity dispersions and the
stellar rotation curve. Here a dark matter halo is added to visible components.
Calculated dispersions are compared with observations along different slit
positions perpendicular and parallel to the galactic major axis. In the
best-fitting model velocity dispersion ellipsoids are radially elongated.
Outside the galactic plane velocity dispersion behaviour is more sensitive to
the dark matter density distribution and allows to estimate dark halo
parameters.Comment: 12 pages, 13 figures, accepted for publication in MNRA
The star formation history of mass-selected galaxies in the COSMOS field
We explore the evolution of the specific star formation rate (SSFR) for
3.6um-selected galaxies of different M_* in the COSMOS field. The average SFR
for sub-sets of these galaxies is estimated with stacked 1.4GHz radio continuum
emission. We separately consider the total sample and a subset of galaxies (SF)
that shows evidence for substantive recent star formation in the rest-frame
optical SED. At 0.2<z<3 both populations show a strong and M_*-independent
decrease in their SSFR towards z=0.2, best described by a power- law (1+z)^n,
where n~4.3 for all galaxies and n~3.5 for SF sources. The decrease appears to
have started at z>2, at least above 4x10^10M_Sun where our conclusions are most
robust. We find a tight correlation with power-law dependence, SSFR (M_*)^beta,
between SSFR and M_* at all z. It tends to flatten below ~10^10M_Sun if
quiescent galaxies are included; if they are excluded a shallow index beta_SFG
-0.4 fits the correlation. On average, higher M_* objects always have lower
SSFRs, also among SF galaxies. At z>1.5 there is tentative evidence for an
upper SSFR-limit that an average galaxy cannot exceed. It is suggested by a
flattening of the SSFR-M_* relation (also for SF sources), but affects massive
(>10^10M_Sun) galaxies only at the highest z. Below z=1.5 there thus is no
direct evidence that galaxies of higher M_* experience a more rapid waning of
their SSFR than lower M_* SF systems. In this sense, the data rule out any
strong 'downsizing'. We combine our results with recent measurements of the
galaxy (stellar) mass function in order to determine the characteristic mass of
a SF galaxy (M_*=10^(10.6\pm0.4)M_Sun). In this sense, too, there is no
'downsizing'. Our analysis constitutes the most extensive SFR density
determination with a single technique to z=3. Recent Herschel results are
consistent with our results, but rely on far smaller samples.Comment: 37 pages, 14 figures, 7 tables; accepted for publication in the
Astrophysical Journal; High resolution versions of all figures available at
www.mpia-hd.mpg.de/homes/karim/research.htm
Childhood maltreatment and intimate partner violence in dissociative disorder patients
Background: Childhood maltreatment (CM) is a risk factor for subsequent intimate partner violence (IPV) in adulthood, with high rates of retrospectively reported CM among IPV victims and perpetrators. A theorized mechanism of the link between CM and IPV is dissociation. Dissociation may allow perpetrators of violence to remain emotionally distant from their behavior and minimize empathy toward those they victimize, enabling them to commit acts of violence similar to their own experiences. Indeed, elevated rates of dissociation and dissociative disorders (DD) have been found among IPV survivors and perpetrators. In addition, in pilot studies, DD clinicians have reported high levels of violent behavior among DD patients. Objective: The present study investigates IPV among DD patients with Dissociative Identity Disorder and Dissociative Disorder Not Otherwise Specified, a group with CM rates of 80–95% and severe dissociative symptoms. Methods: DD clinicians reported on rates of CM and IPV among 275 DD patients in outpatient treatment. DD patients also completed a self-report measure of dissociation. Analyses assessed the associations between CM typologies and IPV, as well as trait dissociation and IPV. Results: Physical and emotional child abuse were associated with physical IPV, and childhood witnessing of domestic violence (DV) and childhood neglect were associated with emotional IPV. Conclusions: The present study is the first to provide empirical support for a possible CM to adult IPV developmental trajectory among DD patients. Future research is needed to better understand the link between CM and IPV among those with trauma and DD
The PN.S Elliptical Galaxy Survey: the dark matter in NGC 4494
We present new Planetary Nebula Spectrograph observations of the ordinary
elliptical galaxy NGC 4494, resulting in positions and velocities of 255 PNe
out to 7 effective radii (25 kpc). We also present new wide-field surface
photometry from MMT/Megacam, and long-slit stellar kinematics from VLT/FORS2.
The spatial and kinematical distributions of the PNe agree with the field stars
in the region of overlap. The mean rotation is relatively low, with a possible
kinematic axis twist outside 1 Re. The velocity dispersion profile declines
with radius, though not very steeply, down to ~70 km/s at the last data point.
We have constructed spherical dynamical models of the system, including Jeans
analyses with multi-component LCDM-motivated galaxies as well as logarithmic
potentials. These models include special attention to orbital anisotropy, which
we constrain using fourth-order velocity moments. Given several different sets
of modelling methods and assumptions, we find consistent results for the mass
profile within the radial range constrained by the data. Some dark matter (DM)
is required by the data; our best-fit solution has a radially anisotropic
stellar halo, a plausible stellar mass-to-light ratio, and a DM halo with an
unexpectedly low central density. We find that this result does not
substantially change with a flattened axisymmetric model.
Taken together with other results for galaxy halo masses, we find suggestions
for a puzzling pattern wherein most intermediate-luminosity galaxies have very
low concentration halos, while some high-mass ellipticals have very high
concentrations. We discuss some possible implications of these results for DM
and galaxy formation.Comment: 29 pages, 17 figures. MNRAS, accepte
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