Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-02-11
Astrophys.J.625:L71-L74,2005
Astronomy and Astrophysics
Astrophysics
5 pages, 4 figures, submitted to ApJ Letters
Scientific paper
10.1086/431146
We propose a model of quasar lifetimes in which observational quasar lifetimes and an intrinsic lifetime of rapid accretion are strongly distinguished by the physics of obscuration by surrounding gas and dust. Quasars are powered by gas funneled to galaxy centers, but for a large part of the accretion lifetime are heavily obscured by the large gas densities powering accretion. In this phase, starbursts and black hole growth are fueled but the quasar is buried. Eventually, feedback from accretion energy disperses surrounding gas, creating a window in which the black hole is observable optically as a quasar, until accretion rates drop below those required to maintain a quasar luminosity. We model this process and measure the unobscured and intrinsic quasar lifetimes in a hydrodynamical simulation of a major galaxy merger. The source luminosity is determined from the black hole accretion rate, calculated from local gas properties. We calculate the column density of hydrogen to the source along multiple lines of sight and use these column densities and gas metallicities to determine B-band attenuation of the source. Defining the observable quasar lifetime as the total time with an observed B-band luminosity above some limit L_B,min, we find lifetimes ~10-20 Myr for L_B,min=10^11 L_sun (M_B=-23), in good agreement with observationally determined quasar lifetimes. This is significantly smaller than the intrinsic lifetime ~100 Myr obtained if attenuation is neglected. The ratio of observed to intrinsic lifetime is also strong function of both the limiting luminosity and the observed frequency.
Cox Thomas J.
Di Matteo Tiziana
Hernquist Lars
Hopkins Philip F.
Martini Paul
No associations
LandOfFree
A Physical Model for the Origin of Quasar Lifetimes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Physical Model for the Origin of Quasar Lifetimes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Physical Model for the Origin of Quasar Lifetimes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-543513