The well-known quasar 3C 48 is the most powerful compact steep-spectrum radio-loud QSO at low redshifts .
It also has two unusual optical features within the radius of the radio jet ( \sim 1 \arcsec ) : ( 1 ) an anomalous , high-velocity narrow-line component , having several times as much flux as does the narrow-line component coinciding with the broad-line redshift ; and ( 2 ) a bright continuum peak ( 3C 48A ) \sim 1 \arcsec northeast of the quasar .
Both of these optical features have been conjectured to be related to the radio jet .
Here we explore these suggestions .

We have obtained Gemini North GMOS integral-field-unit ( IFU ) spectroscopy of the central region around 3C 48 .
We use the unique features of the IFU data to remove unresolved emission at the position of the quasar .
The resolved emission at the wavelength of the high-velocity component is peaked \lesssim 0 \farcs 25 north of the quasar , at virtually the same position angle as the base of the radio jet .
These observations appear to confirm that this high-velocity gas is connected with the radio jet .
However , most of the emission comes from a region where the jet is still well collimated , rather than from the regions where the radio maps indicate strong interaction with an external medium .

We also present the results of HST STIS spectroscopy of 3C 48A .
We show that 3C 48A is dominated by stars with a luminosity-weighted age of \sim 1.4 \times 10 ^ { 8 } years , substantially older than any reasonable estimate for the age of the radio source .
Our IFU data indicate a similar age .
Thus , 3C 48A almost certainly can not be attributed to jet-induced star formation .
The host galaxy of 3C 48 is clearly the result of a merger , and 3C 48A seems much more likely to be the distorted nucleus of the merging partner , in which star formation was induced during the previous close passage .