- What's in your logo?
- "ROSAT PSPC image of the Sun" (by
- Why is it your logo?
- Our survey is
based on X-ray observations with the ROSAT PSPC (in fact,
the yellow-magenta circle approximately corresponds to the central
region of the PSPC field of view where we looked for
clusters). Also, because many in our team work for SAO.
- Most clusters have cooling flows. Don't you miss them
because they look like point sources?
- In fact,
there is little or no difference in the detectability of
high-redshift clusters with flat cores and with cooling flows. We
have explicitly demonstrated that, see §7.1.1 in The Paper. See also discussion
in our paper on the cooling
fraction at high redshifts.
- Won't you miss high-redshift clusters if there are
bright AGNs in the center?
- We've studied this
effect as well (§6.5 in The Paper). Detection
efficiency is decreased significantly only if the AGN is
approximately a factor of 2–3 more luminous than the host
cluster. The effect on the flux estimate is more significant
(basically, from ROSAT data we derive a total luminosity of the
AGN+cluster system). However, we have Chandra data for
all clusters we use in the cosmological work and so we can remove
any contribution from point sources (it was never found to be