Day 162

Tuesday.  Parents -- supposed to have arrived by now (8pm), but still stuck in Frankfurt, so that they can fly to Düsseldorf.  Rented a car, scratched the sides.  Got the telephone company to come, but the DSL/WLAN box doesn't seem to work.  Zahra agreed to sit at my apartment for 2 hrs, which I was grateful for (although it ended up being unnecessary).  Let's see how much reading I get done this week.


1112.3957
Strengthening the open cluster distance scale via VVV photometry
Majaess et al


~14% of open clusters possess 20% absolute error on distance estimates, evaluated from n>3 independent distance estimates; age estimates markedly worse.  Impedes efforts such as calibrating standard candles and constraining masses for substellar companions.  VVV JHK photometry can reduce uncertainty to <10%, demonstrated on NGC 4349 and Pismis 19, which show 60% uncertainty in previous works (>5x reduction in uncertainties).  Indicates (i) existing parameters for the substellar object NGC 4349 127b require revision, partly because new data implies that the host is 20% less massive, (ii) R Cru is not a member of NGC 4349 and should be excluded from period-Wesenheit calibrations that anchor the distance scale, (iii) results for Pismis 19 underscore the advantages from deep VVV JHKs data to examine obscured (Av~4) and differentially reddened intermediate-age clusters.


1112.3958
Old massive globular clusters and the stellar halo of the dwarf starburst galaxy NGC 4449
Strader, Seth, Caldwell


Nearby dwarf starburst galaxy NGC 4449 has an unusual abundance of luminous red star clusters, some of which are old globular clusters with intermediate metallicities ([Fe/H] ~ -1) and subsolar Mg enhancement ([Mg/Fe]~ -0.1 to -0.2).  One of these clusters may be the nucleus of a tidally distrupting dwarf galaxy; the other is very massive (3e6 Msun).  Identified a population of remote halo globular clusters.  Consistent with an emerging picture of the ubiquity of stellar haloes among dwarf galaxies, studies may help distinguish between accretion and in situ scenarios for such halos.