Triggering nuclear and galaxy activity in the Bullet cluster. (arXiv:1912.00075v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Puccetti_S/0/1/0/all/0/1">S. Puccetti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fiore_F/0/1/0/all/0/1">F. Fiore</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bongiorno_A/0/1/0/all/0/1">A. Bongiorno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boutsia_K/0/1/0/all/0/1">K. Boutsia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fassbender_R/0/1/0/all/0/1">R. Fassbender</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Verdugo_M/0/1/0/all/0/1">M. Verdugo</a>
The analysis of the cluster environment is a valuable instrument to The analysis of the cluster environment is a valuable instrument to http://arxiv.org/icons/sfx.gif
investigate the origin of AGN and star-forming galaxies gas fuelling and
trigger mechanisms. To this purpose, we present a detailed analysis of the
point-like X-ray sources in the Bullet cluster field. Thanks to $sim600$ ks
Chandra observations, we produced a catalogue of 381 X-ray point sources up to
a distance of $sim$1.5 virial radius and with flux limits
$sim1times10^{-16}$ and $sim8times10^{-16}$ erg cm$^{-2}$ s$^{-1}$ in the
0.5-2 keV and 2-10 keV bands, respectively. We found a strong (up to a factor
1.5-2) and significant ($ge$4$sigma$) over-density in the full region studied
$0.3R_{200}
investigate the origin of AGN and star-forming galaxies gas fuelling and
trigger mechanisms. To this purpose, we present a detailed analysis of the
point-like X-ray sources in the Bullet cluster field. Thanks to $sim600$ ks
Chandra observations, we produced a catalogue of 381 X-ray point sources up to
a distance of $sim$1.5 virial radius and with flux limits
$sim1times10^{-16}$ and $sim8times10^{-16}$ erg cm$^{-2}$ s$^{-1}$ in the
0.5-2 keV and 2-10 keV bands, respectively. We found a strong (up to a factor
1.5-2) and significant ($ge$4$sigma$) over-density in the full region studied
$0.3R_{200}<R<1.5R_{200}$. We identified optical and infrared counterparts for
$sim$84% and $sim$48% of the X-ray sources, respectively. We obtained new
spectroscopic redshifts for 106 X-ray sources. Spectroscopic and photometric
redshifts of optical and infrared sources have been also collected, and these
sources were used as ancillary samples. We find that the over-density in the
region $0.3R_{200}<R<R_{200}$ is likely due to X-ray AGN (mostly obscured) and
star-forming galaxies both associated to the cluster, while in the more
external region it is likely mostly due to background AGN. The fraction of
cluster galaxies hosting an X-ray detected AGN is 1.0$pm$0.4$%$, nearly
constant with the radius, a fraction similar to that reported in other clusters
of galaxies at similar redshift. The fraction of X-ray bright AGN
(L$_{2-10keV}$$>$10$^{43}$ ergs s$^{-1}$) in the region $0.3R_{200}<R<R_{200}$
is $0.5^{+0.6}_{-0.2}$$%$, higher than that in other clusters at similar
redshift and more similar to the AGN fraction in the field. Finally, the
spatial distributions of AGN and star-forming galaxies, selected also thanks to
their infrared emission, appear similar, thus suggesting that both are
triggered by the same mechanism.
