Washington Photometry of the Globular Clusters in the Virgo Giant Elliptical Galaxy M86

We present a photometric study of the globular clusters (GCs) in the Virgo giant elliptical galaxy M86 based on Washington CT1 images. The colors of the GCs in M86 show a bimodal distribution with a blue peak at (C -T1) = 1.30 and a red peak at (C -T1) = 1.72. The spatial distribution of the red GCs is elongated similarly to that of the stellar halo, while that of the blue GCs is roughly circular. The radial number density profile of the blue GCs is more extended than that of the red GCs. The radial number density profile of the red GCs is consistent with the surface brightness profile of the M86 stellar halo. The GC system has a negative radial color gradient, which is mainly due to the number ratio of the blue GCs to the red GCs increasing as galactocentric radius increase. The bright blue GCs in the outer region of M86 show a blue tilt: the brighter they are, the redder their mean colors get. These results are discussed in comparison with other Virgo giant elliptical galaxies.Comment: 15 pages, 13 figures, Accepted by Journal of the Korean Astronomical Societ

Simultaneous detection of the nonlinear restoring and excitation of a forced nonlinear oscillation: an integral approach

We address in this article, how to calculate the restoring characteristic and the excitation of a nonlinear forced oscillating system. Under the assumption that the forced nonlinear oscillator has a periodic solution with period, we constructed a system of linear equations by introducing time-dependent multipliers. The periodicity assumption helps simplify the system of linear equations. The stability and uniqueness are also presented for the inverse problem. Numerical testing is conducted to show the effectiveness of our presented methodology.Peer ReviewedPostprint (author's final draft

Color Intensity Method for Hydrogel Oxygen Sensor Array

The oxygen imaging technique to obtain a 2-D distribution is a convenient method because it does not require individual addressing of each sensing element in a sensor array. Until recently, color charge coupled devices (CCDs) have rarely been used for oxygen imaging in spite of usefulness for analyzing the spectral content of images. in this work, a color CCD camera was used for luminescence intensity imaging. Two methods of color intensity analysis are investigated and compared. the first method is to analyze the total Red-Green-Blue (RGB) color intensity of the original color image. the second method involves extracting the red color element to enhance the sensitivity of oxygen measurement. Both commercial Redeye oxygen sensor patches and lab-made photopatterned hydrogel (polyethylene glycol) sensor arrays were used to verify these methods. the linearity and sensitivity of oxygen detection based on the red intensity analysis was improved to those of spectrometric measurement and total color intensity analysis. This method also has potential applications in lifetime imaging, multi-analyte detection, and simultaneous structural and functional imaging of biological systems. © 2006 IEEE