Galaxy Zoo is a citizen science project that uses volunteers to classify galaxies from the Sloan Digitial Sky Survey as spiral or elliptical. Now the Galaxy Zoo 2 catalogue has gone public, with even more detailed classifications of galaxies, including bars, bulges, spiral arms, and round and squashed ellipticals.
Huang et al. dig up evidence that distant “red nugget” galaxies grew into the massive ellipticals we see today by consuming smaller, gas-poor galaxies.
Based on galactic rotation curves, we think that spiral galaxies are embedded in massive dark matter halos. Is the same true for elliptical galaxies? Magain and Chantry use gravitational lensing to measure the mass-to-light ratios in 15 elliptical galaxies, and the results might surprise you!
This month’s undergrad research post is all about X-rays. Read on to learn more about studying the X-ray counterpart to a radio pulsar, and examining the evolution of galaxies using X-ray emission.