Juan J. Claria

VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way

Original article can be found at: http://www.sciencedirect.com/science/journal/13841076 Copyright Elsevier B.V.

The Line-of-Sight Depth of Populous Clusters in the Small Magellanic Cloud

We present an analysis of age, metal abundance, and positional data on populous clusters in the Small Magellanic Cloud (SMC) with the ultimate aim of determining the line-of-sight (LOS) depth of the SMC by using these clusters as proxies. Our data set contains 12 objects and is limited to clusters with the highest-quality data for which the ages and abundances are best known and can be placed on an inter- nally consistent scale. We have analyzed the variation of the clustersproperties with position on the sky and with line-of-sight depth. Based on this analysis, we draw the following conclusions: (1) The obser- vational data indicate that the eastern side of the SMC (facing the Large Magellanic Cloud) contains younger and more metal-rich clusters as compared with the western side. This is not a strong correlation because our data set of clusters is necessarily limited, but it is suggestive and warrants further study. (2) Depending on how the reddening is computed to our clusters, we —nd a mean distance modulus that ranges from to 18.82 ^ 0.05. (3) The intrinsic ^1 p LOS depth of the SMC (m ( M) 0 \ 18.71 ^ 0.06 populous clusters in our study is between D6 and D12 kpc, depending primarily on whether we adopt the Burstein & Heiles reddenings or those from Schlegel et al. (4) Viewing the SMC as a triaxial galaxy with declination, right ascension, and LOS depth as the three axes, we —nd axial ratios of approximately 1:2:4. Taken together, these conclusions largely agree with those of previous investigators and under- score the utility of populous star clusters as probes of the structure of the Small Magellanic Cloud.

Optical Light Curve of the Type Ia Supernova 1998bu in M96 and the Supernova Calibration of the Hubble Constant

We present the UBV(RI)KC light curves of the Type Ia supernova SN 1998bu, which appeared in the nearby galaxy M96 (NGC 3368). M96 is a spiral galaxy in the Leo I group that has a Cepheid-based distance. Our photometry allows us to calculate the absolute magnitude and reddening of this supernova. These data, when combined with measurements of the four other well-observed supernovae with Cepheid-based distances, allow us to calculate the Hubble constant with respect to the Hubble flow defined by the distant Calan/Tololo Type Ia sample. We find a Hubble constant of 63.9 ± 2.2(internal) ± 3.5(external) km s-1 Mpc-1, consistent with most previous estimates based on Type Ia supernovae. We note that the two well-observed Type Ia supernovae in Fornax, if placed at the Cepheid distance to the possible Fornax spiral NGC 1365, are apparently too faint with respect to the Calan/Tololo sample calibrated with the five Type Ia supernovae with Cepheid distances to the host galaxies.

An improved metal abundance calibration for the Washington system

A revised metal abundance calibration for the Washington photometric system is presented which represents a significant improvement over previous calibrations in several respects. The abundance sensitivity of various indices is investigated as a function of temperature. The dependence of the various abundance indices on reddening and photometric error is investigated and these open and globular abundance scales are compared to other work.

Background galaxies as reddening probes throughout the Magellanic Clouds

We study the spectral properties in the range 3600 A-6800 A of the nuclear region of galaxies behind the Magellanic Clouds. The radial velocities clarified the nature of the objects as background galaxies or extended objects belonging to the Clouds. For most galaxies behind the main bodies of the LMC and SMC, radial velocities were measured for the first time. In the present sample typical LMC background galaxies are nearby (

On the calibration of the COBE/IRAS dust emission reddening maps

4000 < V({\rm km s^{-1}}) < 6000

A Photometric and Spectroscopic Study of the Southern Open Clusters Pismis 18, Pismis 19, NGC 6005, and NGC 6253

), while SMCs are considerably more distant (

Discovery of VVV CL001. A Low-Mass Globular Cluster Next to UKS~1 in the Direction of the Galactic Bulge

10 000 < V({\rm km s^{-1}}) < 20 000

Red giants in open clusters - IX. NGC 2324, 2818, 3960 and 6259

). We determine the reddening in each line of sight by matching a reddening-free galaxy template with comparable stellar population. For the LMC main body we derive a combined Milky Way and internal reddening value

High-dispersion spectroscopy of giants in metal-poor globular clusters. I - Iron abundances

E(B-V)_{\rm MW+i} = 0.12 \pm 0.10