The Norma Arm Region Chandra Survey: X-ray Populations in the Spiral Arms

We present a catalog of 1415 X-ray sources identified in the Norma arm region Chandra survey (NARCS), which covers a 2 deg x 0.8 deg region in the direction of the Norma spiral arm to a depth of $\approx$20 ks. Of these sources, 1130 are point-like sources detected with $\geq3\sigma$ confidence in at least one of three energy bands (0.5-10, 0.5-2, and 2-10 keV), five have extended emission, and the remainder are detected at low significance. Since most sources have too few counts to permit individual classification, they are divided into five spectral groups defined by their quantile properties. We analyze stacked spectra of X-ray sources within each group, in conjunction with their fluxes, variability, and infrared counterparts, to identify the dominant populations in our survey. We find that $\sim$50% of our sources are foreground sources located within 1-2 kpc, which is consistent with expectations from previous surveys. Approximately 20% of sources are likely located in the proximity of the Scutum-Crux and near Norma arm, while 30% are more distant, in the proximity of the far Norma arm or beyond. We argue that a mixture of magnetic and nonmagnetic CVs dominates the Scutum-Crux and near Norma arms, while intermediate polars (IPs) and high-mass stars (isolated or in binaries) dominate the far Norma arm. We also present the cumulative number count distribution for sources in our survey that are detected in the hard energy band. A population of very hard sources in the vicinity of the far Norma arm and active galactic nuclei dominate the hard X-ray emission down to $f_X\approx10^{-14}$ erg cm$^{-2}$ s$^{-1}$, but the distribution curve flattens at fainter fluxes. We find good agreement between the observed distribution and predictions based on other surveys.Comment: 27 pages, 19 figures, 12 tables, catalog will be made available in published ApJ version and by personal reques

SUSY GUTs under Siege : Proton Decay

SO(10) supersymmetric grand unified theories [SUSY GUTs] provide a beautiful framework for physics beyond the standard model. Experimental measurements of the three gauge couplings are consistent with unification at a scale $M_G \sim 3 \times 10^{16}$ GeV. In addition predictive models for fermion masses and mixing angles have been found which fit the low energy data, including the recent data for neutrino oscillations. SO(10) boundary conditions can be tested via the spectrum of superparticles. The simplest models also predict neutron and proton decay rates. In this paper we discuss nucleon decay rates and obtain reasonable upper bounds. A clear picture of the allowed SUSY spectra as constrained by nucleon decay is presented.Comment: 13 page

An analysis of a Heavy Gluino LSP at CDF : The Heavy Gluino Window

In this paper we consider a heavy gluino to be the lightest supersymmetric particle [LSP]. We investigate the limits on the mass of a heavy gluino LSP, using the searches for excess events in the jets plus missing momentum channel in Run I. The neutral and charged R-hadrons, containing a heavy gluino LSP, have distinct signatures at the Fermilab Tevatron. The range of excluded gluino masses depends on whether the R-hadron is charged or neutral and the amount of energy deposited in the hadronic calorimeter. The latter depends on the energy loss per collision in the calorimeter and the number of collisions; where both quantities require a model for R-hadron- Nucleon scattering. We show how the excluded range of gluino mass depends on these parameters. We find that gluinos with mass in the range between $\sim 35$ GeV and $\sim 115$ GeV are excluded by CDF Run I data. Combined with previous results of Baer et al., which use LEP data to exclude the range 3 - 22$\sim$25 GeV, our result demonstrates that an allowed window for a heavy gluino with mass between 25 and 35 GeV is quite robust. Finally we discuss the relevant differences of our analysis of Tevatron data to that of Baer et al.Comment: 36 pages, 11 figures, added an acknowledgemen

Initial results from NuSTAR observations of the Norma arm

Results are presented for an initial survey of the Norma Arm gathered with the focusing hard X-ray telescope NuSTAR. The survey covers 0.2 deg$^2$ of sky area in the 3-79 keV range with a minimum and maximum raw depth of 15 ks and 135 ks, respectively. Besides a bright black-hole X-ray binary in outburst (4U 1630-47) and a new X-ray transient (NuSTAR J163433-473841), NuSTAR locates three sources from the Chandra survey of this region whose spectra are extended above 10 keV for the first time: CXOU J163329.5-473332, CXOU J163350.9-474638, and CXOU J163355.1-473804. Imaging, timing, and spectral data from a broad X-ray range (0.3-79 keV) are analyzed and interpreted with the aim of classifying these objects. CXOU J163329.5-473332 is either a cataclysmic variable or a faint low-mass X-ray binary. CXOU J163350.9-474638 varies in intensity on year-long timescales, and with no multi-wavelength counterpart, it could be a distant X-ray binary or possibly a magnetar. CXOU J163355.1-473804 features a helium-like iron line at 6.7 keV and is classified as a nearby cataclysmic variable. Additional surveys are planned for the Norma Arm and Galactic Center, and those NuSTAR observations will benefit from the lessons learned during this pilot study.Comment: Accepted for publication in the Astrophysical Journal, 10 pages, 4 figures, 3 table

Preparing for a Postmethod Pedagogy: A Transformative Approach to Curriculum Development

The three parameters of postmethod pedagogy proposed by Kumaravadivelu (2001), particularly a pedagogy of possibility, are in line with and drew on the works of such critical pedagogists as Giroux (1988) whose idea of transformative intellectuals viewed it rightful for every individual teacher and learner to actively participate in the process of learning with their entire social, economic and political experiences; and even make reformations to the direction of pedagogy based on their understanding. However, curriculum development, as an integral part of pedagogy, may inhibit this transformative and dynamic learning by restricting teachers to set and prefabricated materials and guidelines. Nonetheless, teachers play a pivotal role in the realization of this transformative process since they are the executive recipients of curricula. This paper is an attempt to shed light on a transformative approach to curriculum development and holds, a transformative approach to curriculum development requires teachers to have a hand in curriculum development when they are invited by the curriculum to act so; and adapt or transform the curriculum when they are constrained by it

Social media in project management: A systematic narrative literature review

Despite the adoption of social media in many business operations, evidence suggests that the usage of social media for project management activities is scarce. Through this literature review, the paper seeks to clarify the scope of the available knowledge, highlight the significance of new research agendas and address the principal reason for the limited use of social media in project management. A literature review was conducted to analyze the benefits of using social media in project management along with the areas in which it is used, the threats, barriers and enablers of social media adoption. Key areas where social media is used in project management include requirements management, communication management, policymaking, knowledge management and collaboration. Social media usage has shown to improve information sharing, engagement and relationships. Threats include a negative impact on reputation, employee productivity and information privacy. The reviewed literature highlights that the lack of a social media adoption strategy is the principal reason for the limited use of social media in project management. This study contributes to both the project management practice and literature by introducing a model for social media adoption in project management

NuSTAR J163433-4738.7: A Fast X-ray Transient in the Galactic Plane

During hard X-ray observations of the Norma spiral arm region by the Nuclear Spectroscopic Telescope Array (NuSTAR) in 2013 February, a new transient source, NuSTAR J163433-4738.7, was detected at a significance level of 8σ in the 3-10 keV bandpass. The source is consistent with having a constant NuSTAR count rate over a period of 40 ks and is also detected simultaneously by Swift at lower significance. The source is not significantly detected by NuSTAR, Swift, or Chandra in the days before or weeks after the discovery of the transient, indicating that the strong X-ray activity lasted between ~0.5 and 1.5 days. Near-infrared imaging observations were carried out before and after the X-ray activity, but we are not able to identify the counterpart. The combined NuSTAR and Swift energy spectrum is consistent with a power law with a photon index of (90% confidence errors), a blackbody with kT = 1.2 ± 0.3 keV, or a Bremsstrahlung model with keV. The reduced-χ2 values for the three models are not significantly different, ranging from 1.23 to 1.44 for 8 degrees of freedom. The spectrum is strongly absorbed with cm-2, cm-2, and cm-2, for the power-law, blackbody, and Bremsstrahlung models, respectively. Although the high column density could be due to material local to the source, it is consistent with absorption from interstellar material along the line of sight at a distance of 11 kpc, which would indicate an X-ray luminosity >1034 erg s-1. Although we do not reach a definitive determination of the nature of NuSTAR J163433-4738.7, we suggest that it may be an unusually bright active binary or a magnetar