Broad-band X-ray observation of broad-line radio galaxy 3C 109

We present a study of the central engine in the broad-line radio galaxy 3C 109. To investigate the immediate surrounding of this accreting, supermassive black hole, we perform a multi-epoch broad-band spectral analysis of a joint NuSTAR/XMM observation (2017), an archival xmm observation (2005) and the 105-month averaged Swift-BAT data. We are able to clearly separate the spectrum into a primary continuum, neutral and ionized absorption, and a reflection component. The photon index of the primary continuum has changed since 2005 ($\Gamma = 1.61 \substack{+0.02 \\ -0.01} \rightarrow 1.54 \pm{0.02}$), while other components remain unchanged, indicative of minimal geometric changes to the central engine. We constrain the high-energy cutoff of 3C 109 (E$_{\text{cut}}= 49 \substack{+7 \\ -5}$\,keV ) for the first time. The reflector is found to be ionized (log $\xi$ = $2.3 \substack{+0.1 \\ -0.2}$) but no relativistic blurring is required by the data. SED analysis confirms the super-Eddington nature of 3C 109 initially ($\lambda_{Edd} >$ 2.09). However, we do not find any evidence for strong reflection (R = $0.18 \substack{+0.04 \\ -0.03}$) or a steep power law index, as expected from a super-Eddington source. This puts the existing virial mass estimate of 2 $\times 10^{8}$M$_{\odot}$ into question. We explore additional ways of estimating the Eddington ratio, some of which we find to be inconsistent with our initial SED estimate. We obtain a new black hole mass estimate of 9.3 $\times 10^{8}$M$_{\odot}$, which brings all Eddington ratio estimates into agreement and does not require 3C 109 to be super-Eddington.Comment: 13 pages, 8 figure

Modeling the Optical-X-ray Accretion Lag in LMC X-3: Insights Into Black-Hole Accretion Physics

The X-ray persistence and characteristically soft spectrum of the black hole X-ray binary LMC X-3 make this source a touchstone for penetrating studies of accretion physics. We analyze a rich, 10-year collection of optical/infrared (OIR) time-series data in conjunction with all available contemporaneous X-ray data collected by the ASM and PCA detectors aboard the Rossi X-ray Timing Explorer. A cross-correlation analysis reveals an X-ray lag of ~2 weeks. Motivated by this result, we develop a model that reproduces the complex OIR light curves of LMC X-3. The model is comprised of three components of emission: stellar light; accretion luminosity from the outer disk inferred from the time-lagged X-ray emission; and light from the X-ray-heated star and outer disk. Using the model, we filter a strong noise component out of the ellipsoidal light curves and derive an improved orbital period for the system. Concerning accretion physics, we find that the local viscous timescale in the disk increases with the local mass accretion rate; this in turn implies that the viscosity parameter alpha decreases with increasing luminosity. Finally, we find that X-ray heating is a strong function of X-ray luminosity below ~50% of the Eddington limit, while above this limit X-ray heating is heavily suppressed. We ascribe this behavior to the strong dependence of the flaring in the disk upon X-ray luminosity, concluding that for luminosities above ~50% of Eddington, the star lies fully in the shadow of the disk.Comment: Accepted in ApJ (12 pages long in emulateapj format

Exploring Canadian Echinoderm Diversity through DNA Barcodes

Funding: This research was funded, in part, by the Natural Sciences and Engineering Research Council (NSERC) through a Discovery Grant to PDNH and a postgraduate scholarship to EAC. Sequence analysis was enabled by funding from the government of Canada through Genome Canada and the Ontario Genomics Institute in support of the International Barcode of Life Project (OGI-036). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We thank Bridgette Clarkston, Christina Carr, Claudia Hand, Jeremy deWaard, Jim Boutillier, Katy Hind, Robert Frank, Sandra McCubbin, Tanya Brown, Tom Sheldon, and Victoria Frank for contributing specimens and aiding in collections. Kelly Sendall kindly provided access to the echinoderm collections at the Royal British Columbia Museum while we deeply appreciate the help that Chris Mah, Melissa Frey, and Phil Lambert provided with identifications. We also thank staff at the Canadian Centre for DNA Barcoding in the CBG for their aid in sequence acquisition. Lastly, we thank O.S. Klanten and two anonymous reviewers for their helpful suggestions on earlier versions of this manuscript.Peer reviewedPublisher PD

Triple Therapy or Triple Threat: An Analysis of Triple Antiplatelet Therapy Compared to Dual Antiplatelet Therapy

Triple antiplatelet therapy (TAPT, or triple therapy), is an oral medication regimen designed to reduce the risk of major cardiovascular events. It consists of aspirin, clopidogrel or an alternative, and an oral anticoagulant (OAC). It differs from dual antiplatelet therapy (DAPT) due to inclusion of an OAC. Multiple clinical studies have indicated that triple therapy is more effective at clot prevention, when compared to aspirin monotherapy and DAPT, but is associated with a higher risk of major bleeding. Pharmacists have a key role in determining candidates for DAPT and TAPT regimens. Other opportunities for pharmacists include patient monitoring, counseling and medication review throughout treatment with antithrombotic therapy

The Evolution of Critical Thinking Skills in Library Instruction, 1986-2006: A Selected and Annotated Bibliography and Review of Selected Programs

Undergraduate students are increasingly being asked to conduct higher-level research in their areas of study. In order to address undergraduate needs, many academic librarians, especially those charged with crafting instruction, take critical thinking as a given in the teaching of information literacy skills. However, this review of the literature has revealed that though there was some discussion of critical thinking in a library context in the mid-1980’s, the concept did not really take hold until the 1990’s when higher education reform began to appear on many campuses. Additionally, the literature regarding critical thinking skills during this period exhibits four themes: a lack of agreement, among librarians and others, on what critical thinking is and how it can be defined; the importance of subject and course integration in the teaching of critical thinking skills in libraries; the necessity of reaching undergraduate students; and the special challenges of teaching critical thinking skills in an age when technology is changing so rapidly

X-Ray Fluorescence from Super-Eddington Accreting Black Holes

X-ray reverberation has proven to be a powerful tool capable of probing the innermost region of accretion disks around compact objects. Current theoretical effort generally assumes that the disk is geometrically thin, optically thick and orbiting with Keplerian speed. Thus, these models cannot be applied to systems where super-Eddington accretion happens because the thin disk approximation fails in this accretion regime. Furthermore, state-of-the-art numerical simulations show that optically thick winds are launched from the super-Eddington accretion disks, and thereby changing the reflection geometry significantly from the thin disk picture. We carry out theoretical investigations on this topic by focusing on the Fe K$\alpha$ fluorescent lines produced from super-Eddington disks, and show that their line profiles are shaped by the funnel geometry and wind acceleration. We also systematically compare the Fe line profiles from super-Eddington thick disks to those from thin disks, and find that the former are substantially more blueshifted and symmetric in shape. These results are consistent with the observed Fe K$\alpha$ line from the jetted tidal disruption event, Swift J1644, in which a transient super-Eddington accretion disk was formed out of stellar debris. Therefore, careful analysis of the Fe K$\alpha$ line profile can be used to identify systems undergoing super-Eddington accretion.Comment: Typeset using LATEX default style in AASTeX61, 14 pages with 5 figures; updated and accepted to APJ

The Host Galaxy and Rapidly Evolving Broad-line Region in the Changing-look Active Galactic Nucleus 1ES 1927+654

Changing-look active galactic nuclei (AGNs) present an important laboratory to understand the origin and physical properties of the broad-line region (BLR). We investigate follow-up optical spectroscopy spanning $\sim 500$ days after the outburst of the changing-look AGN 1ES\,1927+654. The emission lines displayed dramatic, systematic variations in intensity, velocity width, velocity shift, and symmetry. Analysis of optical spectra and multi-band images indicate that the host galaxy contains a pseudobulge and a total stellar mass of $3.56_{-0.35}^{+0.38} \times 10^{9}\, M_\odot$. Enhanced continuum radiation from the outburst produced an accretion disk wind, which condensed into BLR clouds in the region above and below the temporary eccentric disk. Broad Balmer lines emerged $\sim 100$ days after the outburst, together with an unexpected, additional component of narrow-line emission. The newly formed BLR clouds then traveled along a similar eccentric orbit ($e \approx 0.6$). The Balmer decrement of the BLR increased by a factor of $\sim 4-5$ as a result of secular changes in cloud density. The drop in density at late times allowed the production of \hei\ and \heii\ emission. The mass of the black hole cannot be derived from the broad emission lines because the BLR is not virialized. Instead, we use the stellar properties of the host galaxy to estimate $M_\mathrm{BH} = 1.38_{-0.66}^{+1.25} \times 10^{6}\, M_\odot$. The nucleus reached near or above its Eddington limit during the peak of the outburst. We discuss the nature of the changing-look AGN 1ES\,1927+654 in the context of other tidal disruption events.Comment: 29 pages, 13 figures, published in the Astrophysical Journa