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Workplace Safety and Health: Multiple Challenges Lengthen OSHA's Standard Setting (open access)

Workplace Safety and Health: Multiple Challenges Lengthen OSHA's Standard Setting

A letter report issued by the Government Accountability Office with an abstract that begins "Between 1981 and 2010, the time it took the Department of Labor’s Occupational Safety and Health Administration (OSHA) to develop and issue safety and health standards ranged widely, from 15 months to 19 years, and averaged more than 7 years. Experts and agency officials cited increased procedural requirements, shifting priorities, and a rigorous standard of judicial review as contributing to lengthy time frames for developing and issuing standards. For example, they said that a shift in OSHA’s priorities toward one standard took attention away from several other standards that previously had been a priority."
Date: April 2, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
The Federal Government's Long-Term Fiscal Outlook: Spring 2012 Update (open access)

The Federal Government's Long-Term Fiscal Outlook: Spring 2012 Update

Other written product issued by the Government Accountability Office with an abstract that begins "Federal deficits and debt have reached historic highs in recent years. Congress has taken action to address the fiscal imbalance, but longer-term challenges remain. The Budget Control Act (BCA) of 2011 limits spending over the next decade and leads to an improved fiscal outlook. The act targets discretionary spending, and under both of GAO’s simulations, discretionary spending as a share of the economy would be lower in 2022 than at any point in the last 50 years. Further, as the economy recovers, revenue increases and spending decreases. While the BCA improved the outlook, it did not eliminate the longer-term challenge, in part because it did not focus on the fundamental drivers of the government’s future fiscal imbalances—a structural gap between revenues and spending driven by rising health care costs and demographics. As our 2011 simulations showed, if the Patient Protection and Affordable Care Act (PPACA) is implemented as intended it would have a major effect on the gap but would not eliminate it. The aging of the population and rising health care costs will continue putting upward pressure on spending. Assuming revenue in the long term …
Date: April 2, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Energy Conservation and Climate Change: Factors to Consider in the Design of the Nonbusiness Energy Property Credit (open access)

Energy Conservation and Climate Change: Factors to Consider in the Design of the Nonbusiness Energy Property Credit

A letter report issued by the Government Accountability Office with an abstract that begins "Under criteria for evaluating a tax credit design, both the performance-based and cost-based credits have advantages and disadvantages with neither design being unambiguously the better option based on current information. Both a cost-based and a performance-based credit are designed to reduce energy use and CO2 emissions by providing incentives for energy conservation investment. However, they differ in their relative effectiveness and costs. In general, a performance-based credit is more likely to effectively reduce energy use and CO2 emissions because it rewards energy savings from the investment rather than the cost-based credit’s rewarding of spending regardless of whether this spending results in energy savings. However, the performance-based credit may have significant up-front costs for energy audits, not required by the cost-based credit, which could reduce its effectiveness by discouraging investment. In addition, for taxpayers who do invest, these up-front costs may mean that a performance-based credit may have significantly higher taxpayer compliance and IRS administrative costs than a cost-based credit. A credit’s fairness depends on subjective judgments of how a credit varies with a taxpayer’s income level."
Date: April 2, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Draft INFL Guideline on SIMS (open access)

Draft INFL Guideline on SIMS

Secondary Ion Mass Spectrometry (SIMS) is used for elemental and isotopic analysis of solid samples. The greatest strength of SIMS is the ability to analyze very small areas (as small as 50 nm using the CAMECA NanoSIMS, for example) and to generate high-spatial resolution maps of the distribution of elements and isotopes within the sample. The measurement of the isotopic composition of sample is usually straightforward, only requiring the analysis of the sample and that of an isotopic reference material for determination of the mass bias of the instrument. Quantification of elements, however, involves the analysis of matrix matched standards for the determination of the relative sensitivity factor (a function of both the element to be analyzed and the matrix). SIMS is commonly used in nuclear forensics for exploring the heterogeneity of the material on fine spatial scale.
Date: April 2, 2012
Creator: Kristo, M J
Object Type: Report
System: The UNT Digital Library
Eliminating the Renormalization Scale Ambiguity for Top-Pair Production Using the Principle of Maximum Conformality (open access)

Eliminating the Renormalization Scale Ambiguity for Top-Pair Production Using the Principle of Maximum Conformality

The uncertainty in setting the renormalization scale in finite-order perturbative QCD predictions using standard methods substantially reduces the precision of tests of the Standard Model in collider experiments. It is conventional to choose a typical momentum transfer of the process as the renormalization scale and take an arbitrary range to estimate the uncertainty in the QCD prediction. However, predictions using this procedure depend on the choice of renormalization scheme, leave a non-convergent renormalon perturbative series, and moreover, one obtains incorrect results when applied to QED processes. In contrast, if one fixes the renormalization scale using the Principle of Maximum Conformality (PMC), all non-conformal {l_brace}{beta}{sub i}{r_brace}-terms in the perturbative expansion series are summed into the running coupling, and one obtains a unique, scale-fixed, scheme-independent prediction at any finite order. The PMC renormalization scale {mu}{sub R}{sup PMC} and the resulting finite-order PMC prediction are both to high accuracy independent of choice of the initial renormalization scale {mu}{sub R}{sup init}, consistent with renormalization group invariance. Moreover, after PMC scale-setting, the n!-growth of the pQCD expansion is eliminated. Even the residual scale-dependence at fixed order due to unknown higher-order {l_brace}{beta}{sub i}{r_brace}-terms is substantially suppressed. As an application, we apply the PMC procedure to obtain …
Date: April 2, 2012
Creator: Brodsky, Stanley J. & Wu, Xing-Gang
Object Type: Article
System: The UNT Digital Library
Summary of Current LLNL Projects with the Russian Federation (open access)

Summary of Current LLNL Projects with the Russian Federation

Developing a sophisticated theory to understand the electronic structure of 5f-metals is a great challenge to solid state physics. Complicated electronic structures of 5f-metals make their properties strongly sensitive to small energy changes produced by the addition of a small amount of alloy, impurities, or crystal structure defects caused by irradiation. A theoretical material science technique applicable to investigate these effects is atomistic simulation using Classical Molecular Dynamics (CMD). In contrast to ab initio techniques, CMD may include several million particles, so that there is a possibility of direct simulation of very low concentration impurities and defects (as well as phenomena such as plasticity and polymorphous transitions) under given conditions. The goal is to develop theoretical models to understand and predict changes in materials properties of actinides caused by self-irradiation.
Date: April 2, 2012
Creator: Schilling, O
Object Type: Report
System: The UNT Digital Library
Interfacial Engineering for Highly Efficient-Conjugated Polymer-Based Bulk Heterojunction Photovoltaic Devices (open access)

Interfacial Engineering for Highly Efficient-Conjugated Polymer-Based Bulk Heterojunction Photovoltaic Devices

The aim of our proposal is to apply interface engineering approach to improve charge extraction, guide active layer morphology, improve materials compatibility, and ultimately allow the fabrication of high efficiency tandem cells. Specifically, we aim at developing: i. Interfacial engineering using small molecule self-assembled monolayers ii. Nanostructure engineering in OPVs using polymer brushes iii. Development of efficient light harvesting and high mobility materials for OPVs iv. Physical characterization of the nanostructured systems using electrostatic force microscopy, and conducting atomic force microscopy v. All-solution processed organic-based tandem cells using interfacial engineering to optimize the recombination layer currents vi. Theoretical modeling of charge transport in the active semiconducting layer The material development effort is guided by advanced computer modeling and surface/ interface engineering tools to allow us to obtain better understanding of the effect of electrode modifications on OPV performance for the investigation of more elaborate device structures. The materials and devices developed within this program represent a major conceptual advancement using an integrated approach combining rational molecular design, material, interface, process, and device engineering to achieve solar cells with high efficiency, stability, and the potential to be used for large-area roll-to-roll printing. This may create significant impact in lowering manufacturing cost …
Date: April 2, 2012
Creator: Jen, Alex; Ginger, David; Luscombe, Christine & Ma, Hong
Object Type: Report
System: The UNT Digital Library
Recent Results in Semileptonic B Decays with BaBar (open access)

Recent Results in Semileptonic B Decays with BaBar

In this note, recent results of studies of semileptonic B meson decays from BABAR are discussed and preliminary results given. In particular, a recent measurement of {Beta}(B {yields} D{sup (*)}{tau}{nu}) and the ratio {Beta}(B {yields} D{sup (*)}{tau}{nu})/{Beta}(B {yields} D{sup (*)}{ell}{nu}) is presented. For the D* mode, a branching fraction of 1.79 {+-} 0.13(stat) {+-} 0.17(syst) is found, with a ratio of 0.325 {+-} 0.023(stat) {+-} 0.027(syst). For the D mode, the results are 1.04 {+-} 0.12(stat) {+-} 0.14(syst) and 0.456 {+-} 0.053(stat) {+-} 0.056(syst), respectively. In addition, a study of B{sub s} production and semileptonic decays using data collected in a center-of-mass energy region above the {Upsilon}(4S) resonance is discussed. The semileptonic branching fraction {Beta}(B{sub s} {yields} {ell}{nu}X) is measured to be 9.9{sub -2.1}{sup +2.6}(stat){sub -2.0}{sup +1.3}(syst).
Date: April 2, 2012
Creator: Hamilton, B.K.
Object Type: Article
System: The UNT Digital Library
STABLE SR VS 85SR SORPTION FROM SIMULATED WASTE SOLUTIONS BY MST AND MMST (open access)

STABLE SR VS 85SR SORPTION FROM SIMULATED WASTE SOLUTIONS BY MST AND MMST

A series of tests were performed to examine the sorption of stable Sr versus the sorption of {sup 85}Sr by monosodium titanate (MST) and modified monosodium titanate (mMST) from simulated waste solutions. Earlier testing indicated a discrepancy between the decontamination factors (DFs) obtained by measuring the stable Sr concentrations by inductively coupled plasma - mass spectroscopy (ICP-MS) and the {sup 85}Sr activities by gamma spectroscopy. One hypothesis to explain this discrepancy was that the stable Sr and {sup 85}Sr were in different chemical forms in the simulated solutions. Several simulants were prepared using different methods for adding the Sr and performance tests were carried out using MST and mMST to determine the Sr and {sup 85}Sr DFs with the various simulants. Testing indicated no discrepancy between the Sr and {sup 85}Sr DFs in tests with these simulants.
Date: April 2, 2012
Creator: Taylor-Pashow, K. & Hobbs, D.
Object Type: Report
System: The UNT Digital Library
Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients (open access)

Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients

This thesis presents a two-grid algorithm based on Smoothed Aggregation Spectral Element Agglomeration Algebraic Multigrid (SA-{rho}AMGe) combined with adaptation. The aim is to build an efficient solver for the linear systems arising from discretization of second-order elliptic partial differential equations (PDEs) with stochastic coefficients. Examples include PDEs that model subsurface flow with random permeability field. During a Markov Chain Monte Carlo (MCMC) simulation process, that draws PDE coefficient samples from a certain distribution, the PDE coefficients change, hence the resulting linear systems to be solved change. At every such step the system (discretized PDE) needs to be solved and the computed solution used to evaluate some functional(s) of interest that then determine if the coefficient sample is acceptable or not. The MCMC process is hence computationally intensive and requires the solvers used to be efficient and fast. This fact that at every step of MCMC the resulting linear system changes, makes an already existing solver built for the old problem perhaps not as efficient for the problem corresponding to the new sampled coefficient. This motivates the main goal of our study, namely, to adapt an already existing solver to handle the problem (with changed coefficient) with the objective to achieve …
Date: April 2, 2012
Creator: Kalchev, D
Object Type: Report
System: The UNT Digital Library
Final technical report for the Award DE-FG02-08ER64574, with list of 30 refereed journal articles that acknowledge support from this award. (open access)

Final technical report for the Award DE-FG02-08ER64574, with list of 30 refereed journal articles that acknowledge support from this award.

In this project, we focused on applications of the new warm-rain and ice microphysics schemes to simulate various cloud systems. The overall goal was either to evaluate and improve specific aspects of the schemes (through comparisons with ARM/ASR observations) or to understand the coupling between aerosols, cloud microphysics and cloud dynamics in variety of situations. These studies are relevant to the indirect impact of atmospheric aerosols on climate. Below we report on selected key aspects of the research and then list all peer-reviewed papers that acknowledge support from this grant. Overall, studies partially supported by this grant resulted in 30 peer-reviewed publications (listed below), several dozens of conference presentations (including posters and oral presentations at the ASR Science Team Meetings), and two PhD dissertations. More detailed summaries of our accomplishments are included in yearly reports. Here we summarize only major efforts.
Date: April 2, 2012
Creator: Grabowski, Wojciech W.
Object Type: Report
System: The UNT Digital Library
HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses (open access)

HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses

In our study, a series of lab-scale crucible tests were performed on designed glasses of different compositions to further investigate and simulate the effect of Cr, Ni, Fe, Al, Li, and RuO2 on the accumulation rate of spinel crystals in the glass discharge riser of the HLW melter. The experimental data were used to expand the compositional region covered by an empirical model developed previously (Matyáš et al. 2010b), improving its predictive performance. We also investigated the mechanism for agglomeration of particles and impact of agglomerates on accumulation rate. In addition, the TL was measured as a function of temperature and composition.
Date: April 2, 2012
Creator: Matyas, Josef; Huckleberry, Adam R.; Rodriguez, Carmen P.; Lang, Jesse B.; Owen, Antionette T. & Kruger, Albert A.
Object Type: Report
System: The UNT Digital Library
Searching for Gamma-Ray Blazar Candidates Among the Unidentified INTEGRAL Sources (open access)

Searching for Gamma-Ray Blazar Candidates Among the Unidentified INTEGRAL Sources

The identification of low-energy counterparts for {gamma}-ray sources is one of the biggest challenge in modern {gamma}-ray astronomy. Recently, we developed and successfully applied a new association method to recognize {gamma}-ray blazar candidates that could be possible counterparts for the unidentified {gamma}-ray sources above 100 MeV in the second Fermi Large Area Telescope (LAT) catalog (2FGL). This method is based on the Infrared (IR) colors of the recent Wide-Field Infrared Survey Explorer (WISE) all-sky survey. In this letter we applied our new association method to the case of unidentified INTEGRAL sources (UISs) listed in the fourth soft gamma-ray source catalog (4IC). Only 86 UISs out of the 113 can be analyzed, due to the sky coverage of the WISE Preliminary data release. Among these 86 UISs, we found that 18 appear to have a {gamma}-ray blazar candidate within their positional error region. Finally, we analyzed the Swift archival data available for 10 out these 18 {gamma}-ray blazar candidates, and we found that 7 out of 10 are clearly detected in soft X-rays and/or in the optical-ultraviolet band. We cannot confirm the associations between the UISs and the selected {gamma}-ray blazar candidates due to the discrepancies between the INTEGRAL and the …
Date: April 2, 2012
Creator: Massaro, F.; Paggi, A.; D'Abrusco, R. & Tosti, G.
Object Type: Article
System: The UNT Digital Library
Origin of Room Temperature Broadband Light Emission and Carrier Dynamics in Ag Ion-Implanted Silicon Nanocrystals (open access)

Origin of Room Temperature Broadband Light Emission and Carrier Dynamics in Ag Ion-Implanted Silicon Nanocrystals

This article studies the origin of broad band light emission in the ultraviolet to the red from silicon nanoparticles fabricated using a single low energy silver ion implantation.
Date: April 2, 2012
Creator: Singh, Akhilesh; Grycznski, Karol G. & Neogi, Arup
Object Type: Article
System: The UNT Digital Library
Sweetwater Reporter (Sweetwater, Tex.), Vol. 114, No. 065, Ed. 1 Monday, April 2, 2012 (open access)

Sweetwater Reporter (Sweetwater, Tex.), Vol. 114, No. 065, Ed. 1 Monday, April 2, 2012

Daily newspaper from Sweetwater, Texas that includes local, state, and national news along with advertising.
Date: April 2, 2012
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
The 60-month all-sky BAT Survey of AGN and the Anisotropy of Nearby AGN (open access)

The 60-month all-sky BAT Survey of AGN and the Anisotropy of Nearby AGN

Surveys above 10 keV represent one of the the best resources to provide an unbiased census of the population of Active Galactic Nuclei (AGN). We present the results of 60 months of observation of the hard X-ray sky with Swift/BAT. In this timeframe, BAT detected (in the 15-55 keV band) 720 sources in an all-sky survey of which 428 are associated with AGN, most of which are nearby. Our sample has negligible incompleteness and statistics a factor of {approx}2 larger over similarly complete sets of AGN. Our sample contains (at least) 15 bona-fide Compton-thick AGN and 3 likely candidates. Compton-thick AGN represent a {approx}5% of AGN samples detected above 15 keV. We use the BAT dataset to refine the determination of the LogN-LogS of AGN which is extremely important, now that NuSTAR prepares for launch, towards assessing the AGN contribution to the cosmic X-ray background. We show that the LogN-LogS of AGN selected above 10 keV is now established to a {approx}10% precision. We derive the luminosity function of Compton-thick AGN and measure a space density of 7.9{sub -2.9}{sup +4.1} x 10{sup -5} Mpc{sup -3} for objects with a de-absorbed luminosity larger than 2 x 10{sup 42} erg s{sup -1}. …
Date: April 2, 2012
Creator: Ajello, M.; /KIPAC, Menlo Park; Alexander, D.M.; U., /Durham; Greiner, J.; /Garching, Max Planck Inst., MPE et al.
Object Type: Article
System: The UNT Digital Library
Reliable High Performance Peta- and Exa-Scale Computing (open access)

Reliable High Performance Peta- and Exa-Scale Computing

As supercomputers become larger and more powerful, they are growing increasingly complex. This is reflected both in the exponentially increasing numbers of components in HPC systems (LLNL is currently installing the 1.6 million core Sequoia system) as well as the wide variety of software and hardware components that a typical system includes. At this scale it becomes infeasible to make each component sufficiently reliable to prevent regular faults somewhere in the system or to account for all possible cross-component interactions. The resulting faults and instability cause HPC applications to crash, perform sub-optimally or even produce erroneous results. As supercomputers continue to approach Exascale performance and full system reliability becomes prohibitively expensive, we will require novel techniques to bridge the gap between the lower reliability provided by hardware systems and users unchanging need for consistent performance and reliable results. Previous research on HPC system reliability has developed various techniques for tolerating and detecting various types of faults. However, these techniques have seen very limited real applicability because of our poor understanding of how real systems are affected by complex faults such as soft fault-induced bit flips or performance degradations. Prior work on such techniques has had very limited practical utility because …
Date: April 2, 2012
Creator: Bronevetsky, G
Object Type: Report
System: The UNT Digital Library
Simultaneous Multiwavelength Observation of Mkn 501 in a Low State in 2006 (open access)

Simultaneous Multiwavelength Observation of Mkn 501 in a Low State in 2006

None
Date: April 2, 2012
Creator: Anderhub, H.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Baixeras, C.; Balestra, S. et al.
Object Type: Article
System: The UNT Digital Library
Fermi LAT Observations of LS I +61 303: First Detection of an Orbital Modulation in GeV Gamma Rays (open access)

Fermi LAT Observations of LS I +61 303: First Detection of an Orbital Modulation in GeV Gamma Rays

This Letter presents the first results from the observations of LS I +61{sup o}303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 {+-} 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff, yielding an overall flux above 100 MeV of 0.82 {+-} 0.03(stat) {+-} 0.07(syst) 10{sup -6} ph cm{sup -2} s{sup -1}, with a cutoff at 6.3 {+-} 1.1(stat) {+-} 0.4(syst) GeV and photon index {Gamma} = 2.21 {+-} 0.04(stat) {+-} 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest that the link …
Date: April 2, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
Object Type: Article
System: The UNT Digital Library
Unidentified Gamma-Ray Sources: Hunting Gamma-Ray Blazars (open access)

Unidentified Gamma-Ray Sources: Hunting Gamma-Ray Blazars

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of the unidentified {gamma}-ray sources (UGSs). Despite the large improvements of Fermi in the localization of {gamma}-ray sources with respect to the past {gamma}-ray missions, about one third of the Fermi-detected objects are still not associated to low energy counterparts. Recently, using the Wide-field Infrared Survey Explorer (WISE) survey, we discovered that blazars, the rarest class of Active Galactic Nuclei and the largest population of {gamma}-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Based on this result, we designed an association method for the {gamma}-ray sources to recognize if there is a blazar candidate within the positional uncertainty region of a generic {gamma}-ray source. With this new IR diagnostic tool, we searched for {gamma}-ray blazar candidates associated to the UGS sample of the second Fermi {gamma}-ray catalog (2FGL). We found that our method associates at least one {gamma}-ray blazar candidate as a counterpart each of 156 out of 313 UGSs analyzed. These new low-energy candidates have the same IR properties as the blazars associated to {gamma}-ray sources in the 2FGL catalog.
Date: April 2, 2012
Creator: Massaro, F.; D'Abrusco, R.; Tosti, G.; Ajello, M. & Gasparrini, A.Paggi.D.
Object Type: Article
System: The UNT Digital Library
United abominations: Density functional studies of heavy metal chemistry (open access)

United abominations: Density functional studies of heavy metal chemistry

Carbonyl and nitrile addition to uranyl (UO{sup 2}{sup 2+}) are studied. The competition between nitrile and water ligands in the formation of uranyl complexes is investigated. The possibility of hypercoordinated uranyl with acetone ligands is examined. Uranyl is studied with diactone alcohol ligands as a means to explain the apparent hypercoordinated uranyl. A discussion of the formation of mesityl oxide ligands is also included. A joint theory/experimental study of reactions of zwitterionic boratoiridium(I) complexes with oxazoline-based scorpionate ligands is reported. A computational study was done of the catalytic hydroamination/cyclization of aminoalkenes with zirconium-based catalysts. Techniques are surveyed for programming for graphical processing units (GPUs) using Fortran.
Date: April 2, 2012
Creator: Schoendorff, George
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Iran Sanctions (open access)

Iran Sanctions

None
Date: April 2, 2012
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Conservation Compliance and U.S. Farm Policy (open access)

Conservation Compliance and U.S. Farm Policy

The report discusses the Food Security Act of 1985 that included a number of significant conservation provisions designed to reduce production and conserve soil and water resources. It points out Conservation Compliance Today and Issues for the Next Farm Bill.
Date: April 2, 2012
Creator: Stubbs, Megan
Object Type: Report
System: The UNT Digital Library
The WISE Gamma-Ray Strip Parametrization: The Nature of the Gamma-Ray Active Galactic Nuclei of Uncertain Type (open access)

The WISE Gamma-Ray Strip Parametrization: The Nature of the Gamma-Ray Active Galactic Nuclei of Uncertain Type

Despite the large number of discoveries made recently by Fermi, the origins of the so called unidentified {gamma}-ray sources remain unknown. The large number of these sources suggests that among them there could be a population that significantly contributes to the isotropic gamma-ray background and is therefore crucial to understand their nature. The first step toward a complete comprehension of the unidentified {gamma}-ray source population is to identify those that can be associated with blazars, the most numerous class of extragalactic sources in the {gamma}-ray sky. Recently, we discovered that blazars can be recognized and separated from other extragalactic sources using the infrared (IR) WISE satellite colors. The blazar population delineates a remarkable and distinctive region of the IR color-color space, the WISE blazar strip. In particular, the subregion delineated by the {gamma}-ray emitting blazars is even narrower and we named it as the WISE Gamma-ray Strip (WGS). In this paper we parametrize the WGS on the basis of a single parameter s that we then use to determine if {gamma}-ray Active Galactic Nuclei of the uncertain type (AGUs) detected by Fermi are consistent with the WGS and so can be considered blazar candidates. We find that 54 AGUs out …
Date: April 2, 2012
Creator: Massaro, F.; D'Abrusco, R.; Tosti, G.; Ajello, M.; Gasparrini, D.; Grindlay, J. E. et al.
Object Type: Article
System: The UNT Digital Library