Apr 08

NASA – Hubble Sees Light and Dust in a Nearby Starburst Galaxy

In this inverted question mark galaxy, a bright starburst decorates the end of the crook

Credit: ESA/Hubble and NASA › Larger image

Visible as a small, sparkling hook in the dark sky, this beautiful object is known as J082354.96+280621.6, or J082354.96 for short. It is a starburst galaxy, so named because of the incredibly (and unusually) high rate of star formation occurring within it.

One way in which astronomers probe the nature and structure of galaxies like this is by observing the behavior of their dust and gas components; in particular, the Lyman-alpha emission. This occurs when electrons within a hydrogen atom fall from a higher energy level to a lower one, emitting light as they do so. This emission is interesting because this light leaves its host galaxy only after extensive scattering in the nearby gas — meaning that this light can be used as a pretty direct probe of what a galaxy is made up of.

The study of this Lyman-alpha emission is common in very distant galaxies, but now a study named LARS (Lyman Alpha Reference Sample) is investigating the same effect in galaxies that are closer by. Astronomers chose fourteen galaxies, including this one, and used spectroscopy and imaging to see what was happening within them. They found that these Lyman-alpha photons can travel much further if a galaxy has less dust — meaning that we can use this emission to infer how dusty the source galaxy is.

 

 

Hubble/European Space Agency

via NASA – Hubble Sees Light and Dust in a Nearby Starburst Galaxy.

Apr 06

From Night to Day to Night Again

75x75GLogoSMAll I can say is I would LOVE to take a ride!

Apr 05

NASA – Hubble Breaks Record in Search for Farthest Supernova

Hubble star field with inset, annotated tryptich on the bottom, views of a galaxy before and during a supernova event - then the event itself minus the ambient light from the galaxy

Credit: NASA, ESA, A. Riess (STScI and JHU), and D. Jones and S. Rodney (JHU)

NASA’s Hubble Space Telescope has found the farthest supernova so far of the type used to measure cosmic distances. Supernova UDS10Wil, nicknamed SN Wilson after American President Woodrow Wilson, exploded more than 10 billion years ago.

SN Wilson belongs to a special class called Type Ia supernovae. These bright beacons are prized by astronomers because they provide a consistent level of brightness that can be used to measure the expansion of space. They also yield clues to the nature of dark energy, the mysterious force accelerating the rate of expansion.

via NASA – Hubble Breaks Record in Search for Farthest Supernova.