Dark Matter - Dark Matter It is widely accepted that there...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Dark Matter It is widely accepted that there are vast amounts of unseen material in the universe, perhaps 10 times as much as in detectable galaxies and intergalactic gas. What is the evidence? The basic conclusion comes from galaxy rotation curves , mass distributions inferred from hot gas around ellipticals, the velocity dispersions in clusters of galaxies , and mass tracing via gravitational lensing . Not only do we need to know how much of this exists, but where it is - its distribution can distinguish among stellar remnants, hot and cold elementary particles like massive neutrinos or axions,. .. Recall that most of these techniques are sensitive only to dark matter that is concentrated around galaxies (or more accurately, that galaxies are the marbles rolling up and down hills in dark matter, and that they have had time to fall to the bottom). The amount of dark matter is often given in relation to luminous material through the mass-to- light ratio M/L , most often taking light at the B band; units are solar masses per solar luminosity. Young stellar populations may have values well below unity; older populations may go as high
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 2

Dark Matter - Dark Matter It is widely accepted that there...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online