1,942 research outputs found

    TID Tolerance of Popular CubeSat Components

    Get PDF
    In this paper we report total dose test results of COTS components commonly used on CubeSats. We investigate a variety of analog integrated circuits, a popular microcontroller (PIC24) as well as SD memory card

    A Threat Assessment and Security Analysis of the Three Sports Facilities of Indiana University-Purdue University, Indianapolis NCAA Softball Fields, Carroll Stadium, and the IU Natatorium

    Get PDF
    This research report provides a security assessment of the Softball Fields, Carroll Stadium, and the Natatorium Complex at Indiana University-Purdue University Indianapolis (IUPUI). The purpose of this report is to prevent and mitigate harm to visitors and these facilities which resulting from human-made or natural disasters. Research is guided by the hypothesis that these facilities- due to their respective importance, locations, and attendance patterns are in harm’s way; and that certain strategies of prevention, protection, and mitigation coupled with effective preparedness, response, and recovery can lessen risk, improve security and provide A THREAT ASSESSMENT AND SECURITY ANALYSIS 5 added resilience. Further, “harm’s way” is considered to be either a natural disaster or a human-made disaster, accident, active provocation, or act of terrorism. Methods of analysis include applied research; predominantly utilizing qualitative data with some quantitative investigation. Results of this assessment illustrate that these venues possess numerous vulnerabilities to both natural and human-made threats that if exposed, could result in serious consequences. The two most likely natural hazards identified include straight-line winds and tornadoes. Further, the most likely human threats to these facilities arise from a potential terrorist vehicle attack (TVA) and an active shooter. This project also identifies a specific need for additional planning to prevent an IED or VBIED attack on the Natatorium. Common themes from the attached three case studies reveal that given theses vulnerabilities, the following safety and security adjustments are recommended: Surveillance equipment Metal detectors Security bollards or other temporary barriers Evacuation routes and shelter in place plans Special event security procedures Weather related technology and protocols Staff training for emergency situation

    Limits to Rest-Frame Ultraviolet Emission From Far-Infrared-Luminous z~6 Quasar Hosts

    Full text link
    We report on a Hubble Space Telescope search for rest-frame ultraviolet emission from the host galaxies of five far-infrared-luminous z6z\simeq{}6 quasars and the z=5.85z=5.85 hot-dust free quasar SDSS J0005-0006. We perform 2D surface brightness modeling for each quasar using a Markov-Chain Monte-Carlo estimator, to simultaneously fit and subtract the quasar point source in order to constrain the underlying host galaxy emission. We measure upper limits for the quasar host galaxies of mJ>22.7m_J>22.7 mag and mH>22.4m_H>22.4 mag, corresponding to stellar masses of M<2×1011MM_\ast<2\times10^{11}M_\odot. These stellar mass limits are consistent with the local MBHM_{\textrm{BH}}-MM_\ast relation. Our flux limits are consistent with those predicted for the UV stellar populations of z6z\simeq6 host galaxies, but likely in the presence of significant dust (AUV2.6\langle A_{\mathrm{UV}}\rangle\simeq 2.6 mag). We also detect a total of up to 9 potential z6z\simeq6 quasar companion galaxies surrounding five of the six quasars, separated from the quasars by 1.4''-3.2'', or 8.4-19.4 kpc, which may be interacting with the quasar hosts. These nearby companion galaxies have UV absolute magnitudes of -22.1 to -19.9 mag, and UV spectral slopes β\beta of -2.0 to -0.2, consistent with luminous star-forming galaxies at z6z\simeq6. These results suggest that the quasars are in dense environments typical of luminous z6z\simeq6 galaxies. However, we cannot rule out the possibility that some of these companions are foreground interlopers. Infrared observations with the James Webb Space Telescope will be needed to detect the z6z\simeq6 quasar host galaxies and better constrain their stellar mass and dust content.Comment: 22 pages, 13 figures. Accepted for publication in Ap

    JWST NIRCam Photometry: A Study of Globular Clusters Surrounding Bright Elliptical Galaxy VV 191a at z=0.0513

    Full text link
    James Webb Space Telescope NIRCam images have revealed 443 globular cluster (GC) candidates around the z=0.0513z=0.0513 elliptical galaxy VV 191a. NIRCam broadband observations are made at 0.9-4.5 μ\mum using filters F090W, F150W, F356W, and F444W. Using photometry, the data is analyzed to present color-magnitude diagrams (CMDs) that suggest a fairly uniform population of GCs. Color histograms show a unimodal color distribution that is well fit by a single Gaussian, using color to primarily trace the metallicity. The findings show the sample's globular cluster luminosity function (GCLF) does not reach the turnover value and is, therefore, more luminous than what is typically expected, with an absolute AB magnitude, MF090W=8.70M_{F090W} = -8.70 mag, reaching within nearly one magnitude of the classical turnover value. We attribute this to the completeness in the sample. Models show that the mass estimate of the GCs detected tends to be more massive, reaching upward of 107M\simeq 10^7 M_{\odot}. However, the results show that current GC models do not quite align with the data. We find that the models appear to be bluer than the JWST data in the reddest (F356W-F444W) filters and redder than the data in the bluest (F090W-F150W) filters and may need to be revised to improve the modeling of near-IR colors of old, metal-poor stellar populations.Comment: 11 pages, 7 figure

    The Atacama Cosmology Telescope: Cosmological parameters from three seasons of data

    Get PDF
    We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz and 218 GHz made by the Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to 2010. A model of primary cosmological and secondary foreground parameters is fit to the map power spectra and lensing deflection power spectrum, including contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy from unresolved infrared sources, radio sources, and the correlation between the tSZ effect and infrared sources. The power ell^2 C_ell/2pi of the thermal SZ power spectrum at 148 GHz is measured to be 3.4 +\- 1.4 muK^2 at ell=3000, while the corresponding amplitude of the kinematic SZ power spectrum has a 95% confidence level upper limit of 8.6 muK^2. Combining ACT power spectra with the WMAP 7-year temperature and polarization power spectra, we find excellent consistency with the LCDM model. We constrain the number of effective relativistic degrees of freedom in the early universe to be Neff=2.79 +\- 0.56, in agreement with the canonical value of Neff=3.046 for three massless neutrinos. We constrain the sum of the neutrino masses to be Sigma m_nu < 0.39 eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and Hubble constant measurements. We constrain the amount of primordial helium to be Yp = 0.225 +\- 0.034, and measure no variation in the fine structure constant alpha since recombination, with alpha/alpha0 = 1.004 +/- 0.005. We also find no evidence for any running of the scalar spectral index, dns/dlnk = -0.004 +\- 0.012.Comment: 26 pages, 22 figures. This paper is a companion to Das et al. (2013) and Dunkley et al. (2013). Matches published JCAP versio
    corecore