24,170 research outputs found
The X-ray Power Spectral Density Function and Black Hole Mass Estimate for the Seyfert AGN IC 4329a
We present the X-ray broadband power spectral density function (PSD) of the
X-ray-luminous Seyfert IC 4329a, constructed from light curves obtained via
Rossi X-ray Timing Explorer monitoring and an XMM-Newton observation. Modeling
the 3-10 keV PSD using a broken power-law PSD shape, a break in power-law slope
is significantly detected at a temporal frequency of 2.5(+2.5,-1.7) * 10^-6 Hz,
which corresponds to a PSD break time scale T_b of 4.6(+10.1,-2.3) days. Using
the relation between T_b, black hole mass M_BH, and bolometric luminosity as
quantified by McHardy and coworkers, we infer a black hole mass estimate of
M_BH = 1.3(+1.0,-0.3) * 10^8 solar masses and an accretion rate relative to
Eddington of 0.21(+0.06,-0.10) for this source. Our estimate of M_BH is
consistent with other estimates, including that derived by the relation between
M_BH and stellar velocity dispersion. We also present PSDs for the 10-20 and
20-40 keV bands; they lack sufficient temporal frequency coverage to reveal a
significant break, but are consistent with the same PSD shape and break
frequency as in the 3-10 keV band.Comment: Accepted for publication in ApJ. 11 pages, 6 figures (5 color
Circuit increases capability of hysteresis synchronous motor
Frequency and phase detector circuit enables a hysteresis synchronous motor to drive a load of given torque value at a precise speed determined by a stable reference. This technique permits driving larger torque loads with smaller motors and lower power drain
Barriers to Representation for Detained Immigrants Facing Deportation: Varick Street Detention Facility, A Case Study
There is an evolving crisis in the immigration courts and federal courts of appeals caused by the lack of quality representation for immigrants facing deportation. The problem is particularly acute for immigrants who are detained during their removal proceedings. As part of the Study Group on Immigrant Representation (Katzmann study group), the Subcommittee on Enhancing Mechanisms for Service Delivery undertook a case study of the institutional and legal barriers to quality legal representation for immigrants held at the Varick Street Detention Facility in New York City. Through this lens we hope to offer some useful insights into the core factors contributing to the immigration representation crisis, the institutional barriers that aggravate the crisis, and, finally, to propose a series of reforms to address the crisis
On time, frequency, and polar motion Quarterly reports, 1 Jan. - 30 Jun. 1969
Sudden changes in earth rotational acceleration and polar secular motio
The Price of Alcohol, Wife Abuse, and Husband Abuse
Alcohol consumption has been frequently linked to family violence. The purpose of this paper is to examine the direct relationship between the price of alcohol, which determines consumption, and violence towards spouses. The data come from the 1985 cross section and the 1985-1987 panel of the National Family Violence Survey. The 1985 data are a nationally representative sample while the panel oversamples violent individuals. Dichotomous indicators of severe violence towards wives and husbands are used. A reduced for violence equation is estimated, and individual-level fixed effects are used to control for unobserved characteristics in the panel. A consistent result that emerges from this paper is that an increase in the pure price of alcohol, as measured by a weighted average of the price of alcohol from beer, wine, and liquor, will serve to reduce severe violence aimed at wives. By contrast, the evidence on the propensity of an increase in the price of alcohol to lower violence towards husbands is mixed. When individual level characteristics are not controlled for, the price is not a predictor of violence towards men. However, once the individual traits are controlled for, a negative relationship between the price and violence emerges.
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