Differential cross section analysis in kaon photoproduction using associated legendre polynomials

Angular distributions of differential cross sections from the latest CLAS data sets \cite{bradford}, for the reaction ${\gamma}+p {\to} K^{+} + {\Lambda}$ have been analyzed using associated Legendre polynomials. This analysis is based upon theoretical calculations in Ref. \cite{fasano} where all sixteen observables in kaon photoproduction can be classified into four Legendre classes. Each observable can be described by an expansion of associated Legendre polynomial functions. One of the questions to be addressed is how many associated Legendre polynomials are required to describe the data. In this preliminary analysis, we used data models with different numbers of associated Legendre polynomials. We then compared these models by calculating posterior probabilities of the models. We found that the CLAS data set needs no more than four associated Legendre polynomials to describe the differential cross section data. In addition, we also show the extracted coefficients of the best model.Comment: Talk given at APFB08, Depok, Indonesia, August, 19-23, 200

The M(BH)-Sigma Relation for Supermassive Black Holes

We investigate the differences in the M(BH)-sigma relation derived recently by Ferrarese & Merritt (2000) and Gebhardt et al. (2000). The shallower slope found by the latter authors (3.75 vs. 4.8) is due partly to the use of a regression algorithm that ignores measurement errors, and partly to the value of the velocity dispersion adopted for a single galaxy, the Milky Way. A steeper relation is shown to provide a better fit to black hole masses derived from reverberation mapping studies. Combining the stellar dynamical, gas dynamical, and reverberation mapping mass estimates, we derive a best-fit relation M(BH) = 1.30 (+/- 0.36) X 10^8 (sigma_c/200)^{4.72(+/- 0.36)}, where M(BH) is in solar masses, and sigma in km/s.Comment: The Astrophysical Journal, in pres

Intrinsic Axis Ratio Distribution of Early-type Galaxies From Sloan Digital Sky Survey

Using Sloan Digital Sky Survey Data Release 5, we have investigated the intrinsic axis ratio distribution (ARD) for early-type galaxies. We have constructed a volume-limited sample of 3,922 visually-inspected early-type galaxies at $0.05 \leq z \leq 0.06$ carefully considering sampling biases caused by the galaxy isophotal size and luminosity. We attempt to de-project the observed ARD into three-dimensional types (oblate, prolate, and triaxial), which are classified in terms of triaxiality. We confirm that no linear combination of $randomly$-distributed axis ratios of the three types can reproduce the observed ARD. However, using Gaussian intrinsic distributions, we have found reasonable fits to the data with preferred mean axis ratios for oblate, prolate, and triaxial (triaxials in two axis ratios), $\mu_o=0.44, \mu_p=0.72, \mu_{t,\beta}=0.92, \mu_{t,\gamma}=0.78$ where the fractions of oblate, prolate and triaxial types are \textrm{O:P:T}=0.29^{\pm0.09}:0.26^{\pm0.11}:0.45^{\pm0.13}$. We have also found that the luminous sample ($-23.3 < M_r \leq -21.2$) tends to have more triaxials than the less luminous ($-21.2 < M_r <-19.3$) sample does. Oblate is relatively more abundant among the less luminous galaxies. Interestingly, the preferences of axis ratios for triaxial types in the two luminosity classes are remarkably similar. We have not found any significant influence of the local galaxy number density on ARD. We show that the results can be seriously affected by the details in the data selection and type classification scheme. Caveats and implications on galaxy formation are discussed.Comment: 9 pages, 11 figures, Accepted for publication in Ap

The Dependence of Galaxy Shape on Luminosity and Surface Brightness Profile

For a sample of 96,951 galaxies from the Sloan Digital Sky Survey Data Release 3, we study the distribution of apparent axis ratios as a function of r-band absolute magnitude and surface brightness profile type. We use the parameter fracDeV to quantify the profile type (fracDeV = 1 for a de Vaucouleurs profile; fracDeV = 0 for an exponential profile). When the apparent axis ratio q_{am} is estimated from the moments of the light distribution, the roundest galaxies are very bright (M_r \sim -23) de Vaucouleurs galaxies and the flattest are modestly bright (M_r \sim -18) exponential galaxies. When the apparent axis ratio q_{25} is estimated from the axis ratio of the 25 mag/arcsec^2 isophote, we find that de Vaucouleurs galaxies are flatter than exponential galaxies of the same absolute magnitude. For a given surface brightness profile type, very bright galaxies are rounder, on average, than fainter galaxies. We deconvolve the distributions of apparent axis ratios to find the distribution of the intrinsic short-to-long axis ratio gamma, assuming constant triaxiality T. For all profile types and luminosities, the distribution of apparent axis ratios is inconsistent with a population of oblate spheroids, but is usually consistent with a population of prolate spheroids. Bright galaxies with a de Vaucouleurs profile (M_r < -21.84, fracDeV > 0.9) have a distribution of q_{am} that is consistent with triaxiality in the range 0.4 < T < 0.8, with mean intrinsic axis ratio 0.66 < gamma < 0.69. The fainter de Vaucouleurs galaxies are best fit with prolate spheroids (T = 1) with mean axis ratio gamma = 0.51.Comment: 32 pages, 12 figures, to appear in Ap

XMM-Newton discovery of 2.6 s pulsations in the soft gamma-ray repeater SGR 1627-41

After nearly a decade of quiescence, the soft gamma-ray repeater SGR 1627-41 reactivated on 2008 May 28 with a bursting episode followed by a slowly decaying enhancement of its persistent emission. To search for the still unknown spin period of this SGR taking advantage of its high flux state, we performed on 2008 September 27-28 a 120 ks long X-ray observation with the XMM-Newton satellite. Pulsations with P = 2.594578(6) s were detected at a higher than 6-sigma confidence level, with a double-peaked pulse profile. The pulsed fraction in the 2-12 keV range is 19% +/- 3% and 24% +/- 3% for the fundamental and the second harmonic, respectively. The observed 2-10 keV flux is 3.4E-13 erg/cm^2/s, still a factor of ~ 5 above the quiescent pre-burst-activation level, and the spectrum is well fitted by an absorbed power law plus blackbody model (photon index Gamma = 0.6, blackbody temperature kT = 0.5 keV, and absorption nH = 1.2E+23 cm^-2). We also detected a shell of diffuse soft X-ray emission which is likely associated with the young supernova remnant G337.0-0.1.Comment: Minor changes to match the final version (to appear in The Astrophysical Journal Letters). 5 pages in emulate-apj style, 1 table, 4 figures (1 color

Fractional Q-Switched 1064 nm laser for treatment of atrophic scars in asian skin

Background and Objectives: Asian patients with Fitzpatrick skin type III–IV are a less studied subtype of patients in the medical literature. Q-Switched, 1064 nm neodymium-doped yttrium aluminum garnet (Nd: YAG) laser with a fractionated beam profile (QSF) is a new modality that was reported to be effective in the treatment of scars. This study aims to evaluate the efficacy and safety of QSF Nd: YAG laser in treating scars in Asian patients. Materials and Methods: A total of 29 Subjects were treated with 1064 nm QSF laser. Each patients had three treatments with a fractionated microlens array handpiece every 8 weeks). Efficacy of treatment was evaluated using the Goodman and Baron’s quantitative grading scale before and 3 months after the last treatment. Results: All 29 patients treated had significant improvement of acne scars according to Goodman and Baron’s Quantitative Global Acne Scarring Grading System. No side effect has been observed except some minor erythematous reactions in three patients. Conclusions: Our results confirm that the 1064 nm QSF Nd: YAG laser is a safe and effective technique for treating scars in Asians

Role of the IL-23/IL-17 Pathway in Rheumatic Diseases: An Overview

Interleukin-23 (IL-23) is a pro-inflammatory cytokine composed of two subunits, IL-23A (p19) and IL-12/23B (p40), the latter shared with Interleukin-12 (IL-12). IL-23 is mainly produced by macrophages and dendritic cells, in response to exogenous or endogenous signals, and drives the differentiation and activation of T helper 17 (Th17) cells with subsequent production of IL-17A, IL-17F, IL-6, IL-22, and tumor necrosis factor \u3b1 (TNF-\u3b1). Although IL-23 plays a pivotal role in the protective immune response to bacterial and fungal infections, its dysregulation has been shown to exacerbate chronic immune-mediated inflammation. Well-established experimental data support the concept that IL-23/IL-17 axis activation contributes to the development of several inflammatory diseases, such as PsA, Psoriasis, Psoriatic Arthritis; AS, Ankylosing Spondylitis; IBD, Inflammatory Bowel Disease; RA, Rheumatoid Arthritis; SS, Sjogren Syndrome; MS, Multiple Sclerosis. As a result, emerging clinical studies have focused on the blockade of this pathogenic axis as a promising therapeutic target in several autoimmune disorders; nevertheless, a greater understanding of its contribution still requires further investigation. This review aims to elucidate the most recent studies and literature data on the pathogenetic role of IL-23 and Th17 cells in inflammatory rheumatic diseases

The Ellipticity of the Disks of Spiral Galaxies

The disks of spiral galaxies are generally elliptical rather than circular. The distribution of ellipticities can be fit with a log-normal distribution. For a sample of 12,764 galaxies from the Sloan Digital Sky Survey Data Release 1 (SDSS DR1), the distribution of apparent axis ratios in the i band is best fit by a log-normal distribution of intrinsic ellipticities with ln epsilon = -1.85 +/- 0.89. For a sample of nearly face-on spiral galaxies, analyzed by Andersen and Bershady using both photometric and spectroscopic data, the best fitting distribution of ellipticities has ln epsilon = -2.29 +/- 1.04. Given the small size of the Andersen-Bershady sample, the two distribution are not necessarily inconsistent. If the ellipticity of the potential were equal to that of the light distribution of the SDSS DR1 galaxies, it would produce 1.0 magnitudes of scatter in the Tully-Fisher relation, greater than is observed. The Andersen-Bershady results, however, are consistent with a scatter as small as 0.25 magnitudes in the Tully-Fisher relation.Comment: 19 pages, 5 figures; ApJ, accepte