ar X iv : a st ro - p h / 99 08 10 2 v 1 1 0 A ug 1 99 9 Observations of Candidate z ∼ 1 . 54 Quasar Host Clusters

ar X iv : a st ro - p h / 98 08 21 9 v 1 2 0 A ug 1 99 8 Sgr A ∗ : A supermassive black hole or a spatially extended object ?

ar X iv : a st ro - p h / 99 10 26 1 v 1 1 4 O ct 1 99 9 Cluster environments around quasars at 0

We have observed the galaxy environments around two complete samples of radio-loud (steep-spectrum) and radio-quiet quasars (RLQ and RQQ) at 0.5 ≤ z ≤ 0.8 that are matched in B-luminosity, and find that the environments of both quasar populations are practically indistinguishable. A few objects are found in relatively rich clusters, but on average, they seem to prefer galaxy groups or clusters ...

ar X iv : a st ro - p h / 99 10 19 9 v 1 1 2 O ct 1 99 9 A Companion Galaxy to the Post - Starburst Quasar UN J 1025 − 0040

UNJ1025−0040 is a quasar at z = 0.6344 that shows an extremely bright post starburst population of age ∼ 400 Myr (Brotherton et al. 1999). Images of UNJ1025−0040 show a nearly stellar object 4. 2 SSW of the quasar. We present imaging and spectroscopy that confirm that this object is a companion galaxy at redshift z = 0.6341. We estimate an age of ∼ 800 Myr for the dominant stellar population in...

X iv : a st ro - p h / 99 08 06 9 v 1 6 A ug 1 99 9 ISO observations of the BL Lac object PKS 2155 – 304

ar X iv : a st ro - p h / 99 08 34 8 v 1 3 1 A ug 1 99 9 X - ray Clusters and the Search for Cosmic Flows

We are engaged in an investigation of the relationship between the properties of BCG candidates and X-ray characteristics of their host clusters for a flux-limited (F X = 3 × 10 −12 erg s −1 cm −2) sample of ∼ 250 ACO clusters from the ROSAT all-sky survey. We aim to search for the convergence scale of bulk streaming flows within the ∼ 300 h −1 Mpc defined by this sample. X-ray selection provid...