What is the mean number density of galaxies

Reference no: EM13542169

Galaxy mergers in a rich cluster could impede their use as standard candles over time as they tend to brighten. The Coma cluster of galaxies contains N ~ 1000 galaxies within its half mass radius of rh ~ 1.5 Mpc.

a) What is the mean number density of galaxies within the half mass radius? Suppose the typical physical cross section of a galaxy is sigma ~ 10^-3 Mpc^2.

Reference no: EM13542169

Questions Cloud

Determine the moment of inertia of the turntable : An antique phonograph turntable has a kinetic energy of 2.70×10?2J when turning at an angular velocity of 48.0 rev/min, What is the moment of inertia of the turntable about the rotation axis

Calculate the angle through which the blade has turned : A circular saw blade of diameter 0.175m starts from rest. In a time interval of 6.05s it accelerates with constant angular acceleration to an angular velocity of 130 rad/s. Find the angle through which the blade has turned

Compute the number of revolutions made by the motor : An electric fan is turned off, and its angular velocity decreases uniformly from 540 rev/min to 240rev/min in a time interval of length 3.65s, Find the number of revolutions made by the motor

Explain the central limit theorem : Explain the central limit theorem in the context of the current problem, and indicate how it was useful in finding these probabilities - Find the critical Z values

What is the mean number density of galaxies : Galaxy mergers in a rich cluster could impede their use as standard candles over time as they tend to brighten. What is the mean number density of galaxies within the half mass radius

Obtain the magnitude of the maximum charge on one plate : A capacitor is connected across an ac generator whose frequency is 753 Hz and whose peak output voltage is 140 V. What is the magnitude of the maximum charge on one plate of the capacitor

Find the impedance of the series combination : When a resistor is connected across the terminals of an ac generator (103 V) that has a fixed frequency, there is a current of 0.505 A in the resistor. find the impedance of the series combination

Compute what was the maximum force required to stretch it : To stretch a certain spring by 2.20 from its equilibrium position requires 7.00 of work. What was the maximum force required to stretch it by that distance

Calculate what is the force constant of this spring : To stretch a certain spring by 2.20 from its equilibrium position requires 7.00 of work. What is the force constant of this spring

User Account

All Pages