A galaxy cluster in the innermost Zone of Avoidance, close to the radio
  phoenix VLSSJ2217.5+594
  The steep spectrum radio source VLSSJ2217.5+5943 shows a complex, filamentary
morphology and a curved spectrum. Therefore, the source has previously been
classified as a radio phoenix. However, no galaxy cluster associated with this
radio source has been confidently detected so far because the source is located
in the direction of the innermost zone of the Galactic Plane at b = +2.4 degr
(innermost Zone of Avoidance, ZoA). We analysed archival observations in the
near infrared (UKIDSS) and mid infrared (Spitzer) to select the galaxies in the
immediate neighbourhood of the radio source. A sample of 23 galaxies was
selected as candidate cluster members. Furthermore, we carried out deep
integral field spectroscopy covering 6450 to 10500 AA with the red unit of the
Hobby-Eberly Telescope second generation low resolution spectrograph (LRS2-R).
We also reanalysed archival GMRT observations at 325 and 610 MHz. We selected
23 galaxies within a radius of 2.5 arcmin, centered on RA=22:17.5, DEC=+59:43
(J2000). Spectra were obtained for three of the brightest galaxies. For two
galaxies we derived redshifts of z = 0.165 and z = 0.161, based on NaD
absorption and TiO band heads. Their spectra correspond to E-type galaxies.
Both galaxies are spatially associated with VLSSJ2217.5+5943. The spectrum of
the third galaxy, which is slightly more distant from the radio source,
indicates a LINER at z = 0.042. It is apparently a foreground galaxy with
respect to the cluster we identified. VLSSJ2217.5+5943 is associated with a
massive galaxy cluster at redshift z = 0.163 +- .003, supporting its
classification as radio phoenix.
