Tabulated Chandra observing time here combines two observations taken on 2001
April 23 and 2001 June 03. There is no evidence for variation in the nuclear
X-ray flux over this time period.
The evidence for an absorbed nuclear X-ray component in this source is
marginal. Adding a second component to the fit clearly improves it, and the
normalization of the second component is not consistent with zero at the 90 per
cent confidence level: however, the column density of the intrinsic absorber is
not constrained (Table 7). Accordingly, there is a large uncertainty on the
luminosity of the absorbed component.
3C 228. The source was observed in two separate exposures of 10 ks (observation
ID 2453) and 13 ks (observation ID 2095), respectively, after flare screening.
The shorter observation detected 281 net counts, while the longer has 365,
consistent with no flux variation between the two.
3C 228 (z=0.5524; Fig. 11).--The galaxy is compact with a high central surface
3C 228 (z = 0.55; Fig. 27).-Our images were obtained in rather poor
conditions. Nonetheless, we are able to determine that the [O II] image
shows no extended emission on a scale larger than 2.5". The radio source
is a large double (Jenkins et al. 1977).
The identification, magnitude and redshift have been taken from Spinrad
et al. (1985)
Empty to 48-inch IIIaJ limit.
Wyndham, J.D. (1966) Ap. J., 144, 459
identification probably a plate flaw.
Object "A" (Fig. 4) suggested by
Sandage, A.R., and Wyndham, J.D.
(1965) A.J., 141, 328.
is very blue but far from radio center:
(delta(RA) = 31 arcsec, delta(DEC) = 47 arcsec)