bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suitability of quality-of-life outcome measures in palliative care in the South African setting
Authors: Maree Johanna E. , Jansen Van Rensburg Jacoba J.M. 
Published: March 2015

AbstractObjective:Quality of life (QoL) is a multidimensional, subjective, and highly individual phenomenon. The current study speaks to the QoL domains identified by palliative patients living in Africa. The need to identify these domains has been recognized but seemed to still be lacking. This study filled this knowledge gap by providing the domains and by giving directions in terms of the assessment of QoL in palliative patients living in resource-restricted communities in South Africa.Method:We followed a multi-method approach and conducted a literature review to identify and describe the multidimensional QoL instruments used in African palliative care. A secondary analysis design and open-coding method was employed to identify the domains influencing the QoL of palliative patients living in a resource-restricted South African community, after which we compared these domains to the domains assessed by the identified QoL instruments.Results:We found that two multidimensional QoL of life instruments—the Missoula–Vitas Quality of Life Index (MVQoLI) and the Functional Assessments of Chronic Illness Therapy–Palliative Care (FACIT–Pal)—have been used in African palliative care and have identified various domains, grouped as four themes: physical concerns, psychosocial issues, financial restraints, and existential issues. The patient-identified QoL domains were to a great extent not assessed by the MVQoLI and FACIT–Pal.Significance of Results:Our study highlights the complexity of QoL and QoL assessment. A more accurate representation of the QoL of palliative patients living in resource-restricted communities might be obtained by using individualized measures or exploring what QoL means to these patients and selecting QoL instruments accordingly.
Stochastic approach to modeling the γ-ray variability of Fermi/LAT blazars
Authors: Sobolewska M. , Siemiginowska A. , Kelly B. , Nalewajko K. 
Published: March 2015

AbstractWe studied the γ-ray variability of 13 blazars observed with the Fermi Large Area Telescope (LAT). These blazars were among the brightest ones monitored during the first 4 years of the Fermi sky survey. We modelled their γ-ray light curves with the Ornstein-Uhlenbeck (OU) process or mixed OU process. The power spectral density (PSD) of the OU process is a zero-centered Lorentzian function, proportional to 1/fα with α changing at a characteristic time scale, τ0, from 0 (τ ≫ τ0) to 2 (τ ≪ τ0). The PSD of the mixed OU process has in addition an intermediate part with 0 < α < 2 between the long and short characteristic time scales. We show that the OU model provides a good description of the Fermi/LAT light curves of three blazars in our sample. For the first time we provide constraints on the characteristic γ-ray time scale of variability in two BL Lac sources, 3C 66A and PKS 2155-304. We find that the mixed OU process describes the light curves of the remaining 10 blazars better than the OU process. We infer that their Fermi/LAT PSD resemble power-law functions and constrain their PSD slopes.
Very high energy gamma-rays from flat spectrum radio quasars
Authors: Lindfors Elina 
Published: March 2015

AbstractThe detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra and distance. Nevertheless four FSRQs are now known to be VHE emitters. The detection of the VHE γ-rays has challenged the emission models of these sources. The sources are also found to exhibit very different behavior. I will give an overview of what is known about the VHE emission of these sources and about the multiwavelength signatures that are connected to the VHE gamma-ray emission.
Multifrequency VLBI follow up study of strong γ-ray flares in the blazars 3C273 and 3C279
Authors: Lisakov Mikhail M. , Kovalev Yuri Y. 
Published: March 2015

AbstractWe present multifrequency VLBI observations of the blazars 3C273 and 3C279 after detecting strong γ-ray flares in both of them. 3C273 exhibited a prominent flare in γ-rays in September 2009 which was followed by a strong flare in the 7 mm VLBI core and emergence of a new feature in the parsec scale jet. We have used time delay between flares in different wavebands together with kinematic analysis to determine that the γ-ray emission zone in 3C273 is located 3.6-5.3 pc upstream from the apparent 7 mm core. We have also analyzed frequency dependent core position to measure a deprojected distance between 7 mm core and the true base of the jet: 1-6 pc for 3C273 and 1-3 pc for 3C279, depending on observing epoch. For 3C279 light curve analysis did not give a robust γ-radio delay because there were too many overlapping flares in this source during considered period.
First results from HAWC: monitoring the TeV gamma-ray sky
Authors: Lauer Robert J. ,   for the HAWC Collaboration
Published: March 2015

AbstractThe High Altitude Water Cherenkov (HAWC) Observatory is a wide-field gamma-ray detector sensitive to primary energies between 100 GeV and 100 TeV. The array is being built at an altitude of 4100 m a.s.l. on the Sierra Negra volcano near Puebla, Mexico. Data taking has already started while construction continues, with the completion projected for early 2015. The design is optimized to detect extended air showers induced by gamma rays that pass through the array and to reconstruct the directions and energies of the primary photons. With a duty cycle close to 100% and a daily coverage of ~8 sr of the sky, HAWC will perform a survey of TeV emissions from many different sources. The northern active galactic nuclei will be monitored for up to 6 hours each day, providing unprecedented light curve coverage at energies comparable to those of imaging air Cherenkov telescopes. HAWC has been in scientific operation with more than 100 detector modules since August 2013. Here we present a preliminary look at the first results and discuss the efforts to integrate HAWC in multi-wavelength studies of extragalactic jets.
Using the methods of wavelet analysis and singular spectrum analysis in the study of the variability of flux of radio sources 3C120 and BL Lac in the radio range
Authors: Donskykh Ganna , Ryabov Michael , Sukharev Artem , Aller Margo 
Published: March 2015

AbstractWe investigated the monitoring data of extragalactic sources 3C120 and BL Lac. This monitoring was held with University of Michigan 26-meter radio telescope. To study flux density of extragalactic sources 3C120 and BL Lac at frequencies of 14.5, 8 and 4.8 GHz, the wavelet analysis and singular spectrum analysis were used. Calculating the integral wavelet spectra revealed long-term components (11 - 4 years) and short-term components (3.4 - 0.7 years) in 3C120. BL Lac has long-period components of 7 - 8 years and short-term components of 1 - 4 years. Studying of VLBI radio maps (by the program Mojave) allowed investigating features of components movement relatively to the VLBI core. The data of radio astronomy observations were also investigated using singular spectrum analysis. This method does not use the analyzing function, so its calculations allow to distinguish various components of investigated series with a high accuracy. To get spectral power distribution depending on time in the studied narrowband components obtained by singular spectrum analysis, short-term Fourier transformation was used.
Variability of the counterpart to the gamma-ray blazar GT0106+613
Authors: Luque-Escamilla Pedro L. , Martí J. , Ramírez-Valenzuela E. , Muñoz-Arjonilla A. J. , Paredes J. M. 
Published: March 2015

AbstractWe present the optical/infrared counterpart to GT0106+613, a transient gamma-ray source believed to be a blazar. Long-term differential photometry and satellite information was used to confirm the variability in optical/infrared wavelengths, correlated with gamma-ray flares from the source. An intense optical flare with no counterpart in gamma-rays is also remarkable.
The mid-infrared spectral characteristics of blazars
Authors: Smith Howard A. , Massaro F. , D'Abrusco R. , Paggi A. , Cowperthwaite P. , Masetti N. , Giroletti M. , Tosti G. , Landoni M. 
Published: March 2015

AbstractWe previously reported discovering that blazars have distinctive infrared colors as seen in the WISE mission. Of particular note are γ-ray blazars, the locus of whose colors roughly overlaps with QSOs contours but which is more tightly delimited and bluer than ULIRGs and Seyferts. Since a large fraction of γ-ray sources are unassociated with any point source, but are expected to be blazars, identifying a WISE-candidate blazar in the γ-ray source field enables efficient followup studies. In an effort to better understand why blazars have these colors, we reduced and analyzed Spitzer Infrared Spectrometer (IRS) measurements on 73 blazars of varying types, some at several epochs. These spectra can be used to study the continuum emission (non-thermal), and search for atomic or other spectral features.
Symmetric and triangle-shaped variability of blazars
Authors: Yoshida Kenji 
Published: March 2015

AbstractSymmetric and triangle-shaped flux variability in X-ray and gamma-ray light curves is observed from many blazars. We derived the X-ray spectrum changing in time by using a kinetic equation of high energy electrons. Giving linearly changing the injection of low energy electrons into accelerating and emitting region, we obtained the preliminary results that represent the characteristic X-ray variability of the linear flux increase with hardening in the rise phase and the linear decrease with softening in the decay phase.
AGN feedback by relativistic jets
Authors: Bicknell G. V. , McNamara B. R. , Nawaz M. A. , Sutherland R. S. , Umemura M. , Wagner A. Y. 
Published: March 2015

AbstractFeedback provided by relativistic jets may be effective in shaping the galaxy luminosity function. The quenching mode (quasar mode) at redshifts ~2-3 potentially disperses gas in star-forming galaxies. The maintenance mode (radio mode) heats the gas in galaxy clusters counteracting cooling flows. A number of authors have examined the effect of relativistic jets in dispersing clouds in the kpc-scale inhomogeneous interstellar medium of evolving galaxies. We have also investigated a particular case of maintenance-mode feedback in our simulation of the iconic radio galaxy / cooling flow cluster Hydra A. Modelling of the knots produced by the jets in the inner 10 kpc provides an estimate of 0.8 – 0.9 c for the velocities of the jets in agreement with other velocity estimates for FR1 jets. The addition of jet precession provides realistic simulations of the morphology of the Hydra A radio source and raises interesting questions as to the role of black hole and disk precession, in general, in galaxy formation.
The parsec-scale structure, kinematics, and polarization of radio-loud narrow-line Seyfert 1 galaxies
Authors: Richards J. L. , Lister M. L. , Savolainen T. , Homan D. C. , Kadler M. , Hovatta T. , Readhead A. C. S. , Arshakian T. G. , Chavushyan V. 
Published: March 2015

AbstractSeveral narrow-line Seyfert 1 galaxies (NLS1s) have now been detected in gamma rays, providing firm evidence that at least some of this class of active galactic nuclei (AGN) produce relativistic jets. The presence of jets in NLS1s is surprising, as these sources are typified by comparatively small black hole masses and near- or super-Eddington accretion rates. This challenges the current understanding of the conditions necessary for jet production. Comparing the properties of the jets in NLS1s with those in more familiar jetted systems is thus essential to improve jet production models. We present early results from our campaign to monitor the kinematics and polarization of the parsec-scale jets in a sample of 15 NLS1s through multifrequency observations with the Very Long Baseline Array. These observations are complemented by fast-cadence 15 GHz monitoring with the Owens Valley Radio Observatory 40 m telescope and optical spectroscopic monitoring with with the 2 m class telescope at the Guillermo Haro Astrophysics Observatory in Cananea, Mexico.
Very high energy neutrino expectation from Fanaroff-Riley I sources
Authors: Marinelli Antonio , Fraija Nissim 
Published: March 2015

AbstractFanaroff-Riley I radiogalaxies have been observed in TeV gamma-rays during the last decades. The origin of the emission processes related with this energy band is still under debate. Here we consider the case of the two closest Fanaroff-Riley I objects: Centaurus A and M87. Their entire broadband spectral energy distributions and variability fluxes show evidences that leptonic models are not sufficient to explain their fluxes above 100 GeV. Indeed, both objects have been imaged by LAT instrument aboard of Fermi telescope with measured spectra well connected with one-zone leptonic models. However, to explain the TeV spectra obtained with campaigns by H.E.S.S., for Centaurus A, and by VERITAS, MAGIC and H.E.S.S. for M87, different emission processes must be introduced. In this work we introduce hadronic scenarios to describe the TeV gamma-ray fluxes observed and to obtain the expected neutrino counterparts for each considered TeV campaign. With the obtained neutrino spectra we calculate, through Monte Carlo simulations, the expected neutrino event rate in a hypothetical Km3 neutrino telescope and we compare the results with what has been observed by IceCube experiment up to now.
A survey of X-ray emission from 100 kpc radio jets
Authors: Schwartz D. A. , Marshall H. L. , Worrall D. M. , Birkinshaw M. , Perlman E. , Lovell J. E. J. , Jauncey D. , Murphy D. , Gelbord J. , Godfrey L. , Bicknell G. 
Published: March 2015

AbstractWe have completed a Chandra snapshot survey of 54 radio jets that are extended on arcsec scales. These are associated with flat spectrum radio quasars spanning a redshift range z=0.3 to 2.1. X-ray emission is detected from the jet of approximately 60% of the sample objects. We assume minimum energy and apply conditions consistent with the original Felten-Morrison calculations in order to estimate the Lorentz factors and the apparent Doppler factors. This allows estimates of the enthalpy fluxes, which turn out to be comparable to the radiative luminosities.
Spatially resolved studies of extragalactic jets in high redshift radio galaxies
Authors: Morabito Leah K. , Deller Adam , Oonk J. B. R. , Röttgering Huub , Miley George 
Published: March 2015

AbstractThe correlation between radio spectral steepness and redshift has been successfully used to find high redshift (z ⩾ 2) radio galaxies, but the origin of this relation is unknown. The ultra-steep spectra of high-z radio sources make them ideally suited for studies with the Low Band Antenna of the new Low Frequency Array, which covers 10–80 MHz and has baselines up to about 1300 km. As part of an ongoing survey, we use the longest baselines to map the low-frequency (< 70 MHz) spatial distributions along the jets of 5 bright extended steep spectrum high-z radio sources. From this, we will determine whether the spectra change over these spatially resolved sources, thereby constraining particle acceleration processes. We present early results from our low-frequency survey of ultra-steep spectrum radio galaxies. The first low frequency long baseline images of these objects are presented.
Early evolution stage of AGN
Authors: Kunert-Bajraszewska M. , Labiano A. , Siemiginowska A. , Guainazzi M. , Gawroński M. 
Published: March 2015

AbstractRadio sources are divided into two distinct morphological groups of objects: Fanaroff-Riley type I and type II sources. There is a relatively sharp luminosity boundary between these at low frequency. The nature of the FR division is still an open issue, as are the details of the evolutionary process in which younger and smaller GHz-peaked spectrum (GPS) and compact steep spectrum (CSS) sources become large-scale radio structures. It is still unclear whether FRII objects evolve to become FRIs, or whether a division has already occurred amongst CSS sources and some of these then become FRIs and some FRIIs. We explored evolution scenarios of AGNs using new radio, optical and X-ray data of unstudied so far Low Luminosity Compact (LLC) sources. We suggest that the determining factors of the further evolution of compact radio objects could occur at subgalactic (or even nuclear) scales, or they could be related to the radio jet - interstellar medium (ISM) interactions and evolution. Our studies show that the evolutionary track could be related to the interaction, strength of the radio source and excitation levels of the ionized gas instead of the radio morphology of the young radio source.
The North Middle Lobe of Centaurus A
Authors: Neff Susan G. , Eilek Jean A. , Owen Frazer N. 
Published: March 2015

AbstractWe present new, deep VLA 327 MHz, GALEX Far-UV, and Hα images of the inner ~50 kpc of Centaurus A. We find the structure identified by Morganti et al. 1999 as a possible “large scale jet” is part of a knotty, linear feature within a broader region of diffuse radio emission. The linear feature is coincident with a narrow ribbon of Far-UV and Hα emission that extends 6-35 kpc from the galaxy core, as well with a similar ridge of soft X-ray emission. The Far-UV image also shows that a strong starburst is occurring in the central dusty disk, with a star-formation rate of ~ 2M⊙ yr−1. We suggest that the various peculiar phenomena seen to the NE of the galaxy can be explained by a wind from the starburst disk, enhanced by energy input from the AGN.
Jet-gas interactions at crucial jet power for feedback
Authors: Worrall D. M. , Birkinshaw M. 
Published: March 2015

AbstractMost X-ray studies of radio-mode feedback have concentrated on locally-abundant low-power radio sources in relatively rich cluster environments. But the scaling found between mechanical and radiative power, when combined with the radio luminosity function, means that half of the heating in the local Universe is expected from higher-power sources, which lie within a factor of about three of the FRI/II transition, and these sources encounter a wide range of atmosphere properties. We summarize what is observed at FRI/II transition powers from a complete sample observed with modest Chandra exposure times. We then discuss two systems with deep Chandra data. In one we find that the work done in driving shocks exceeds that in evacuating cavities. This source also displays a remarkable jet-cloud interaction, and revealing hotspot X-ray emission. In the second we find evidence of radio-emitting plasma running along boundaries between gas of different temperature, apparently lubricating the gas flows and inhibiting heat transfer, and itself being heavily structured by the process.
X-ray jets and nuclear emission in low redshift early-type galaxies
Authors: Jones Christine , Forman William , Churazov Eugene , Nulsen Paul 
Published: March 2015

AbstractDue to its high angular resolution, the Chandra Observatory has allowed the discovery and detailed study of extragalactic X-ray jets. Although supermassive black holes are regularly found in the cores of massive galaxies and X-ray emission is detected from ~80% of these, X-ray and radio jets are only detected in a small fraction of “normal” galaxies. X-ray jets are either single-sided or double-sided and, with only one possible exception, are found to have radio emission. However many radio jets are not detected in current X-ray observations. The expanding jets produce cavities in the surrounding hot gas in the galaxy halos. By determining how much gas has been pushed out of these cavities, we can determine the mechanical energy and power of the jet.
Radio source evolution from galaxy core to intracluster medium
Authors: Maciel Tamela , Alexander Paul 
Published: March 2015

AbstractThere is mounting evidence that mechanical kinetic-mode AGN feedback is important in galaxy evolution, and in order to quantify this feedback, detailed models of radio source evolution are required. Self-similar analytic models exist for large powerful radio sources but the evolution of young precursor radio sources is not yet fully understood. In this talk we present a versatile dynamical and radiative model for young source evolution on sub-kiloparsec scales, which extends existing self-similar models into a more complete radio source evolutionary model. This semi-analytic model is successful in reproducing the strong spectral aging observed in compact symmetric objects.
Evidence for jet driven outflows: the case of 3C293
Authors: Mahony E. K. , Oonk J. B. R. , Morganti R. , Oosterloo T. A. , Emonts B. H. C. , Tadhunter C. N. 
Published: March 2015

AbstractThe tight correlations observed between galaxies and their SMBH provides compelling evidence that the evolution of the galaxy and its central black hole are strongly linked. This is generally attributed to feedback mechanisms which, according to simulations, often take the form of outflows of gas, quenching star formation in the host galaxy and halting accretion onto the central black hole. While there are a number of plausible ways that outflows could be produced, recent results have shown that in some cases radio jets could be responsible for driving fast outflows of gas. One such example is seen in the nearby radio galaxy 3C293. In this talk I will present results from JVLA radio observations where we detect fast outflows (~1200 km/s) of neutral gas which are being driven by the radio-jet approximately 0.5 kpc from the central core, providing direct evidence for jet-ISM interaction. This is accompanied with recent IFU observations showing that ionised gas outflows are also being driven by the radio jet. Pinpointing the location of these outflows enables us to derive crucial parameters, such as the mass outflow rates and kinetic energy involved, which we can compare to predictions from galaxy evolution simulations.
The implications of bent jets in galaxy groups
Authors: Nielsen Danielle M. , Wilcots Eric M. 
Published: March 2015

AbstractBent-double sources, sometimes referred to as wide- or narrow-angle tails, are most likely the result of ram pressure from either the motion of the source through a dense medium or the "cluster weather." These unusual sources have long been associated with high density, high velocity dispersion, and turbulent environments of massive clusters, however a surprising number have been found in lower mass systems. We focus our attention on a sample of such sources in galaxy groups where the velocity dispersion is significantly lower. We have acquired multi-frequency radio continuum observations using the GMRT of our bent-double sample and new optical spectroscopy to measure the velocity dispersion of groups hosting these bent-double sources. Our goal is to derive an estimate of the density of the intergalactic medium in these groups. Here, we present GMRT data for one source in our sample.