Bl Lac Object

Active galaxyConcentration of 10 to 10 stars, dust and gas, that are gravitationally bound. Our galaxy contains ~2 × 10 stars. There are four main types of galaxies: • Elliptical
• Lenticular
• Spiral
• Irregular
characterized by very rapid (day to day) variability in total luminosityBasic property used to characterize stars, luminosity is defined as the total energy radiated by a star each second. An object’s luminosity is often compared to that of the Sun (Lsun = 4 × 1033 ergs/s = 3.9 × 10 Watts). Luminosity has the same units as power (energy per, no emission lines, strong nonthermal radiation, and starlike appearance. It is apparently a radio galaxy aligned so that we are looking down the jet into the nucleusCore of an atom, where nearly the entire mass and all positive charge is concentrated. It consists of protons and neutrons..