1,025 research outputs found
X-ray properties of an Unbiased Hard X-ray Detected Sample of AGN
The SWIFT gamma ray observatory's Burst Alert Telescope (BAT) has detected a
sample of active galactic nuclei (AGN) based solely on their hard X-ray flux
(14-195 keV). In this paper, we present for the first time {\it XMM-Newton}
X-ray spectra for 22 BAT AGNs with no previously analyzed X-ray spectra. If our
sources are a representative sample of the BAT AGN, as we claim, our results
present for the first time global X-ray properties of an unbiased towards
absorption (n), AGN
sample. We find 9/22 low absorption (n cm), simple power
law model sources, where 4 of these sources have a statistically significant
soft component. Among these sources, we find the presence of a warm absorber
statistically significant for only one Seyfert 1 source, contrasting with the
ASCA results of \citet{rey97} and \citet{geo98}, who find signatures of warm
absorption in half or more of their Seyfert 1 samples at similar redshifts.
Additionally, the remaining sources (14/22) have more complex spectra, well-fit
by an absorbed power law at keV. Five of the complex sources are
classified as Compton-thick candidates. Further, we find four more sources with
properties consistent with the hidden/buried AGN reported by Ueda {\it et al.}
(2007). Finally, we include a comparison of the {\it XMM-Newton} EPIC spectra
with available SWIFT X-ray Telescope (XRT) observations. From these
comparisons, we find 6/16 sources with varying column densities, 6/16 sources
with varying power law indices, and 13/16 sources with varying fluxes, over
periods of hours to months. Flux and power law index are correlated for objects
where both parameters vary.Comment: 39 pages, 16 figures, accepted to Ap
Do Differing Levels of Boldness Influence the Success of Translocation? : A Pilot Study on Red Squirrels (Sciurus vulgaris)
Peer reviewedPublisher PD
Levelling Up Learning: Exploring the Impact of Gamification in Flipped Classrooms
In recent years, the integration of gamification into educational settings has garnered significant attention as a means to enhance student engagement and learning outcomes. By leveraging gamified elements such as points and leaderboards, educators aim to promote active participation, motivation, and deeper understanding among students. This study investigates the effects of gamification on student engagement in a flipped classroom environment. The findings suggest that gamification strategies, when effectively implemented, can have a positive impact on student motivation and engagement. This paper concludes with recommendations for educators, potential challenges such as superficial engagement and demotivation, and future directions for research to address these challenges and further explore the potential of gamification in fostering student success
Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes
We present the Suzaku broad band observations of two AGNs detected by the
Swift/BAT hard X-ray (>15 keV) survey that did not have previous X-ray data,
Swift J0601.9-8636 and Swift J0138.6-4001. The Suzaku spectra reveals in both
objects a heavily absorbed power law component with a column density of NH =~
10^{23.5-24} cm^{-2} that dominates above 10 keV, and an intense reflection
component with a solid angle >~ from a cold, optically thick medium. We
find that these AGNs have an extremely small fraction of scattered light from
the nucleus, <~ 0.5% with respect to the intrinsic power law component. This
indicates that they are buried in a very geometrically-thick torus with a small
opening angle and/or have unusually small amount of gas responsible for
scattering. In the former case, the geometry of Swift J0601.9-8636 should be
nearly face-on as inferred from the small absorption for the reflection
component. The discovery of two such objects in this small sample implies that
there must be a significant number of yet unrecognized, very Compton thick AGNs
viewed at larger inclination angles in the local universe, which are difficult
to detect even in the currently most sensitive optical or hard X-ray surveys.Comment: 4 pages, 3 figures, accepted for publication in ApJ Lette
Galaxy Cluster Pressure Profiles as Determined by Sunyaev Zel'dovich Effect Observations with MUSTANG and Bolocam I: Joint Analysis Technique
We present a technique to constrain galaxy cluster pressure profiles by
jointly fitting Sunyaev-Zel'dovich effect (SZE) data obtained with MUSTANG and
Bolocam for the clusters Abell 1835 and MACS0647. Bolocam and MUSTANG probe
different angular scales and are thus highly complementary. We find that the
addition of the high resolution MUSTANG data can improve constraints on
pressure profile parameters relative to those derived solely from Bolocam. In
Abell 1835 and MACS0647, we find gNFW inner slopes of and , respectively when
and are constrained to 0.86 and 4.67 respectively. The fitted
SZE pressure profiles are in good agreement with X-ray derived pressure
profiles.Comment: 12 pages, 12 figures. Submitted to Ap
Myeloid sarcoma without circulating leukemia mimicking gastrointestinal malignancy and lymphoma
We present an unusual case of myeloid sarcoma with ascites and abdominal pain in which initial clinical, laboratory, and imaging studies suggested a gastrointestinal malignancy or lymphoma. Subsequent detection of leukemic ascites and blasts in a gastric, small bowel, and skin biopsy supported a diagnosis of myeloid sarcoma. Bone marrow biopsy revealed 15% blasts, and cytogenetics with an inversion 16 rearrangement was diagnostic of acute myeloid leukemia (AML). Positron emission tomography-computed tomography performed at presentation to stage a presumptive lymphoma found later utility in following the burden of extramedullary disease. Standard AML induction chemotherapy resulted in complete remission and was followed by three rounds of high dose cytarabine consolidation. The patient unfortunately relapsed leading to re-induction followed by allogeneic stem cell transplantation. This report describes the presentation, assessment, and management of myeloid sarcoma
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