5,286 research outputs found

    The Ultra-Fast Outflow of WKK 4438: Suzaku and NuSTAR X-ray Spectral Analysis

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    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 vout=0.319βˆ’0.008+0.005cv_{\rm out}=0.319^{+0.005}_{-0.008}c 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 (ZArβ€²>6ZβŠ™Z^{\prime}_{\rm Ar}>6Z_{\odot}) and a slight iron over-abundance (ZFeβ€²=2.6βˆ’2.0+1.9ZβŠ™Z^{\prime}_{\rm Fe}=2.6^{+1.9}_{-2.0}Z_{\odot}) are found in our spectral modelling. Based on Monte-Carlo simulations, the detection of the UFO is estimated to be around at 3Οƒ\sigma significance. The fast wind most likely arises from a radius of β‰₯20rg\geq20r_g away from the central black hole. The disk is accreting at a high Eddington ratio (Lbol=0.4βˆ’0.7LEddL_{\rm bol}=0.4-0.7L_{\rm Edd}). The mass outflow rate of the UFO is comparable with the disk mass inflow rate (MΛ™out>30%MΛ™in\dot M_{\rm out}>30\%\dot M_{\rm in}), assuming a maximum covering factor. The kinetic power of the wind might not be high enough to have influence in AGN feedback (EΛ™wind/Lbolβ‰ˆ3βˆ’5%\dot E_{\rm wind}/L_{\rm bol}\approx 3-5\%) due to a relatively small column density (12βˆ’4+9Γ—102212^{+9}_{-4}\times10^{22}~cmβˆ’2^{-2}). However note that both the inferred velocity and the column density could be lower limits owing to the low viewing angle (i=23βˆ’2+3i=23^{+3}_{-2}∘^{\circ}).Comment: 7 pages, 3 figures, accepted by MNRA

    The Absolute Magnitude Distribution of Kuiper Belt Objects

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    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, Ξ±1=1.5βˆ’0.2+0.4\alpha_{\textrm{1}}=1.5_{-0.2}^{+0.4}, and break magnitude, HB=6.9βˆ’0.2+0.1H_{\textrm{B}}=6.9_{-0.2}^{+0.1} (r'-band). The hot population has a shallower bright-end slope of, Ξ±1=0.87βˆ’0.2+0.07\alpha_{\textrm{1}}=0.87_{-0.2}^{+0.07}, and break magnitude HB=7.7βˆ’0.5+1.0H_{\textrm{B}}=7.7_{-0.5}^{+1.0}. Both populations share similar faint end slopes of Ξ±2∼0.2\alpha_2\sim0.2. We estimate the masses of the hot and cold populations are ∼0.01\sim0.01 and \sim3\times10^{-4} \mbox{ M_{\bigoplus}}. The broken power-law fit to the Trojan H-distribution has Ξ±1=1.0Β±0.2\alpha_\textrm{1}=1.0\pm0.2, Ξ±2=0.36Β±0.01\alpha_\textrm{2}=0.36\pm0.01, and HB=8.3H_{\textrm{B}}=8.3. 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 Hr’≲3H_{\textrm{r'}}\lesssim3, 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

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    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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