hw3 - 1. Also nd the uncertainty in this M/L . Compare your...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Ph 444 Problem Set 3 Due: Friday, October 1, 2010 1. Calculate the critical mass density and its uncertainty using the current best estimate of the Hubble constant, H 0 = 70 . 6 ± 1 . 8 km s 1 Mpc 1 . 2. The Millennium Galaxy Catalog yields a local luminosity density in galaxies of j = ((1 . 986 ± 0 . 031) × 10 8 L Mpc 3 ) p H 0 100 km s 1 Mpc 1 P . The dependence on H 0 comes from the use of the Hubble law to calculate distances to galaxies. Calculate the average mass-to-light ratio ( M/L ) in solar units for galaxies that would be required if galaxies produced the critical mass calculated in problem
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1. Also nd the uncertainty in this M/L . Compare your value with the value of M/L 2 M /L expected for a normal stellar population. 3. Ryden problem 4.4 4. Ryden problem 4.5 Hint: to calculate the pressure you can either start with Ryden equation (4.32) or use the expression for the pressure of a gas of non-interacting particles with number density n , momentum p , and speed v : P = npv/ 3....
View Full Document

Ask a homework question - tutors are online