The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

17 pages, Accepted to MNRAS

Scientific paper

We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z~0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the ~4 Ms CDF-S and ~2 Ms CDF-N and z = 0.1-0.6 in the ~250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keV to B-band luminosity ratio (L_X/L_B proportional to [1 + z]^1.2) since z~1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z~1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of ~1.4-2.6 times larger than the average radiative cooling power from hot gas over the redshift range z~0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies 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 The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-515115

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.