New analysis in the field of open cluster Collinder 223

The present study of the open cluster Collinder 223 (Cr 223) has been mainly depended on the photoelectric data of Claria & Lapasset (1991; hereafter CL91). This data of CL91 has been used with the cluster's image of AAO-DSS in order to re-investigate and improve the main parameters of Cr 223. Stellar count has been achieved to determine the stellar density, the cluster's center and the cluster's diameter. In addition, the luminosity function, mass function, and the total mass of the cluster have been estimated.Comment: 12 pages, 8 figure

Day-side z'-band emission and eccentricity of Wasp-12b

We report the detection of the eclipse of the very-hot Jupiter WASP-12b via z'-band time-series photometry obtained with the 3.5-meter ARC telescope at Apache Point Observatory. We measure a decrease in flux of 0.082+/-0.015% during the passage of the planet behind the star. That planetary flux is equally well reproduced by atmospheric models with and without extra absorbers, and blackbody models with f > 0.585+/-0.080. It is therefore necessary to measure the planet at other wavelengths to further constrain its atmospheric properties. The eclipse appears centered at phase = 0.5100 (+0.0072,-0.0061), consistent with an orbital eccentricity of |e cos w| = 0.016 (+0.011,-0.009) (see note at end of Section 4). If the orbit of the planet is indeed eccentric, the large radius of WASP-12b can be explained by tidal heating.Comment: One more author added. Version accepted for publication on ApJ

Deep, Wide-field CCD Photometry for the Open Cluster NGC3532

We present the results of a deep, wide-field CCD survey for the open cluster NGC~3532. Our new $BV(RI)_{c}$ photometry effectively covers a one square degree area and reaches an unprecedented depth of $V\sim21$ to reveal that NGC~3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams, including supplementing our photometry with $JHK_{s}$ data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence. Our results confirm previous findings that NGC~3532 lies fairly near to the Sun [$(m-M)_0=8.46\pm0.05$; $492^{+12}_{-11}$~pc] and has an extremely low reddening for its location near the Galactic plane [$E(B-V)=0.028\pm0.006$]. Moreover, an age of $\sim300$\,Myr has been derived for the cluster by fitting a set of overshooting isochrones to the well-populated upper main-sequence. This new photometry also extends faint enough to reach the cluster white dwarf sequence, as confirmed by our photometric recovery of eight spectroscopically identified members of the cluster. Using the location of these eight members, along with the latest theoretical cooling tracks, we have identified $\sim30$ additional white dwarf stars in the $[V,~(B-V)]$ color-magnitude diagram that have a high probability of belonging to NGC~3532. The age we derive from fitting white dwarf isochrones to the locus of these stars, $300\pm100$\,Myr, is consistent with the age derived from the turnoff. Our analysis of the photometry also includes an estimation of the binary star fraction, as well as a determination of the cluster's luminosity and mass functions.Comment: Accepted for publication in AJ. 55 pages, 21 figures. High-quality version with complete data tables can be downloaded from http://www.phys.lsu.edu/~jclem/NGC3532

Lifting the Dusty Veil With Near- and Mid-Infrared Photometry: I. Description and Applications of the Rayleigh-Jeans Color Excess Method

The Milky Way (MW) remains a primary laboratory for understanding the structure and evolution of spiral galaxies, but typically we are denied clear views of MW stellar populations at low Galactic latitudes because of extinction by interstellar dust. However, the combination of 2MASS near-infrared (NIR) and Spitzer-IRAC mid-infrared (MIR) photometry enables a powerful method for determining the line of sight reddening to any star: the sampled wavelengths lie in the Rayleigh-Jeans part of the spectral energy distribution of most stars, where, to first order, all stars have essentially the same intrinsic color. Thus, changes in stellar NIR-MIR colors due to interstellar reddening are readily apparent, and (under an assumed extinction law) the observed colors and magnitudes of stars can be easily and accurately restored to their intrinsic values, greatly increasing their usefulness for Galactic structure studies. In this paper we explore this "Rayleigh-Jeans Color Excess" (RJCE) method and demonstrate that use of even a simple variant of the RJCE method based on a single reference color, (H-[4.5um]), can rather accurately remove dust effects from previously uninterpretable 2MASS color-magnitude diagrams of stars in fields along the heavily reddened Galactic mid-plane, with results far superior to those derived from application of other dereddening methods. We also show that "total" Galactic midplane extinction looks rather different from that predicted using 100um emission maps from the IRAS/ISSA and COBE/DIRBE instruments as presented by Schlegel et al. Instead, the Galactic mid-plane extinction strongly resembles the distribution of 13-CO (J=1->0) emission. Future papers will focus on refining the RJCE method and applying the technique to understand better not only dust and its distribution, but the distribution of stars intermixed with the dust in the low-latitude Galaxy.Comment: Accepted to ApJ; 21 pages, 17 figure

Neural Stem and Progenitor Cells as a Tool for Tissue Regeneration

Neural stem and progenitor cells (NSPC) can differentiate to neurons and glial cells. NSPC are easily propagated in vitro and are therefore an attractive tool for tissue regeneration. Traumatic brain injury (TBI) is a common cause for death and disabilities. A fundamental problem following TBI is tissue loss. Animal studies aiming at cell replacement have encountered difficulties in achieving sufficient graft survival and differentiation. To improve outcome of grafted cells after experimental TBI (controlled cortical impact, CCI) in mice, we compared two transplantation settings. NSPC were transplanted either directly upon CCI to the injured parenchyma, or one week after injury to the contralateral ventricle. Enhanced survival of transplanted cells and differentiation were seen when cells were deposited in the ventricle. To further enhance cell survival, efforts were made to reduce the inflammatory response to TBI by administration of ibuprofen to mice that had been subjected to CCI. Inflammation was reduced, as monitored by a decrease in inflammatory markers. Cell survival as well as differentiation to early neuroblasts seemed to be improved. To device a 3D system for future transplantation studies, NSPC from different ages were cultured in a hydrogel consisting of hyaluronan and collagen. Cells survived and proliferated in this culturing condition and the greatest neuronal differentiating ability was seen in cells from the newborn mouse brain. NSPC were also used in a model of peripheral nervous system injury, and xeno-transplanted to rats where the dorsal root ganglion had been removed. Cells survived and differentiated to neurons and glia, furthermore demonstrating their usefulness as a tool for tissue regeneration