5,286 research outputs found
The Ultra-Fast Outflow of WKK 4438: Suzaku and NuSTAR X-ray Spectral Analysis
Previous X-ray spectral analysis has revealed an increasing number of AGNs
with high accretion rates where an outflow with a mildly relativistic velocity
originates from the inner accretion disk. Here we report the detection of a new
ultra-fast outflow (UFO) with a velocity of in addition to a relativistic disk reflection
component in a poorly studied NLS1 WKK~4438, based on archival \nustar and
\suzaku observations. The spectra of both \suzaku and \nustar observations show
an Fe~\textsc{xxvi} absorption feature and the \suzaku data also show evidence
for an Ar~\textsc{xviii} with the same blueshift. A super-solar argon abundance
() and a slight iron over-abundance
() are found in our spectral
modelling. Based on Monte-Carlo simulations, the detection of the UFO is
estimated to be around at 3 significance. The fast wind most likely
arises from a radius of away from the central black hole. The disk
is accreting at a high Eddington ratio (). The
mass outflow rate of the UFO is comparable with the disk mass inflow rate
(), assuming a maximum covering factor.
The kinetic power of the wind might not be high enough to have influence in AGN
feedback () due to a relatively
small column density (~cm). However note that
both the inferred velocity and the column density could be lower limits owing
to the low viewing angle ().Comment: 7 pages, 3 figures, accepted by MNRA
The Absolute Magnitude Distribution of Kuiper Belt Objects
Here we measure the absolute magnitude distributions (H-distribution) of the
dynamically excited and quiescent (hot and cold) Kuiper Belt objects (KBOs),
and test if they share the same H-distribution as the Jupiter Trojans. From a
compilation of all useable ecliptic surveys, we find that the KBO
H-distributions are well described by broken power-laws. The cold population
has a bright-end slope, , and break
magnitude, (r'-band). The hot population has
a shallower bright-end slope of, , and
break magnitude . Both populations share
similar faint end slopes of . We estimate the masses of the
hot and cold populations are and \sim3\times10^{-4} \mbox{
M_{\bigoplus}}. The broken power-law fit to the Trojan H-distribution has
, , and
. The KS test reveals that the probability that the Trojans
and cold KBOs share the same parent H-distribution is less than 1 in 1000. When
the bimodal albedo distribution of the hot objects is accounted for, there is
no evidence that the H-distributions of the Trojans and hot KBOs differ. Our
findings are in agreement with the predictions of the Nice model in terms of
both mass and H-distribution of the hot and Trojan populations. Wide field
survey data suggest that the brightest few hot objects, with
, do not fall on the steep power-law slope of fainter
hot objects. Under the standard hierarchical model of planetesimal formation,
it is difficult to account for the similar break diameters of the hot and cold
populations given the low mass of the cold belt.Comment: Accepted to the Astrophysical Journa
None for the money: how we actually make monetary decisions: a literature review
Often, critics of academic scholarship point to the failure of academic findings translating to practical applications. This paper tackles an issue that most people deal with every single day, how to make smart decisions with their money. The literature scrutinizing the psychology of monetary decisions is vast. However, in a literature so comprehensive it can be easy to miss the forest for all the trees. By returning primarily to two authors who did much of the foundational research on the subject and expanding upon their work, this paper examines the overwhelming prevalence, causes, and future implications of irrational monetary decision making
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