by Courtney Dressing | Jan 19, 2012 | Daily Paper Summaries
Where should astronomers look to find terrestrial planets? Raymond et al. argue that debris disks are signposts of terrestrial planet formation.
by Courtney Dressing | Jan 6, 2012 | Daily Paper Summaries
Moons in other solar systems are common in science fiction. Are they common in the universe as well? Kipping et al. are using Kepler data to find out.
by Courtney Dressing | Dec 14, 2011 | Daily Paper Summaries
Today, Mercury rotates only three times in two Mercury years. How did the planet get to this state? Was Mercury tidally locked in the past?
by Courtney Dressing | Dec 8, 2011 | Current Events
The First Kepler Science Conference is occurring this week at NASA Ames. Check out this summary of the conference to learn about the exciting results from the Kepler mission.
by Courtney Dressing | Nov 10, 2011 | Daily Paper Summaries
Paper title: Bars rejuvenating bulges? Evidence from stellar population analysis Authors: Paula Coelho and Dimitri A. Gadotti First author’s affiliation:Núcleo de Astrofísica Teórica, Universidade Cruzeiro do Sul, São Paulo, Brasil SummaryAs you may recall from Nathan Sanders’ April post, some spiral galaxies have central bulges with high concentrations of stars. Coelho and Gadotti examine a sample of 575 of these galaxies to investigate whether the presence or absence of a bar (a bar-shaped overdensity of stars) influences the rate of star formation in the central bulge. Astronomers expect to see a higher star formation rate in the bulges of barred galaxies because bars can transport gas from the outer regions of the galaxy into the center and supply fuel for growing stars. Previous detections of star-formation indicators (such as enhanced Hα emission) have indicated that the current star formation rates are higher in barred spirals than in unbarred spirals, but Coelho and Gadotti take the alternative approach of determining the ages of the stellar populations in the bulges. They find that the bulges of barred galaxies are systematically younger than the bulges of unbarred galaxies, which is consistent with the expectation that bars should promote star formation. The Galaxy SampleIn a previous paper, Gadotti derived stellar masses, bulge stellar masses, bar properties, and other parameters for a sample of face-on galaxies observed by Sloan Digital Sky Survey (SDSS). All of the galaxies had stellar masses above 10^10 solar masses and redshifts between 0.02 and 0.07. Selecting face-on galaxies reduced the effect of dust and simplified the process of identifying bars and bulges in the galaxies. In this paper, Coelho...
