NGC 7619. We extracted spectra in seven contiguous, concentric annuli with
outer radii 0.2', 0.6', 1.1', 1.8', 2.5', 3.4', and 4.5' (2.5, 8.0, 16,
25, 35, 48, and 63 kpc), respectively. We did not find strong evidence of
a Z_Fe_ abundance gradient and so we tied abundances between all annuli.
Only one hot gas component was required in each annulus to fit the data.
The temperature was seen to rise from ~0.76 keV in the center to ~0.95 keV
in the outer annulus. Our measured Z_Fe_ is in excellent agreement with
that reported by Buote & Fabian (1998).
NGC 7619 Radio; a normal E3
Its ellipticity in the central region is 0.1, reaches a maximum of
0.25 and decreases in the outer regions. The position angle varies
slight and monotonically through the radius, and the isophotes are
The galaxies NGC 7192, NGC 7562 and NGC 7619 are the most displaced
with respect to the average in the flux ratios diagram. Its infrared
colors are likely to be compatible with the average Galactic clusters
population. NGC 7619 is a member of Pegasus I cluster, being the
brightest component, followed by NGC 7626. Both present disky isophotes
and abrupt variations of A3 and B3 coefficients, possibly indicating
high extinction regions. Forbes & Thomson (1992) found evidence of
tidal interactions between these two galaxies; since these interactions
can induce star formation bursts, this could explain, at least in part,
the fact that its infrared colors are among the bluest of our sample.
Figure 3 shows the comparison with Whitmore et al. (1987), Jedrzejewski
& Schechter (1987) (PA = 34 ^deg^ ) and Franx et al. (1989). Our data
agree, within the errors, with both Jedrzejewski & Schechter (1989) and
Franx et al. (1989). A zero point difference is evident, both in
systemic velocity and velocity dispersion, with Whitmore et al. (1987)
data. On the other side, the shape of their velocity profile is more
similar to our one than that of Jedrzejewski & Schechter (1987) and
Franx et al. (1989). Our central velocity dispersion is in agreement
with that derived by 7Sam since their adopted value is 337 km s^-1^
(raw values range from 325 to 381 km s^-1^).
Peg I Cluster
Aug 20/21, 1979
103aO + GG385
NGC 7619 is the brightest member of the Pegasus I Cluster, whose
mean redshift of the listed members is
1975b). As described in the comments for NGC 7626 (panel 3), NGC 7619
played a major role in Hubble's (1929) formulation of the
redshift-distance relation. It was the galaxy used by Humason (1929)
to obtain the largest redshift known at the time. The two spectra
taken by Humason that showed the highest redshift known at that time
required exposures of 33 and 45 hours with the Mount Wilson 100-inch
Hooker reflector. (Much-superior spectra can be obtained today with
modern spectrographs and detectors in less than one minute).
The morphological type of NGC 7619 is normal E3.
Brightest galaxy in the Pegasus I Cluster, with NGC 7611, NGC 7615,
NGC 7623, NGC 7626, and NGC 7631.
Mem. S.A. Ital., 44, 65, 1973 = Cont. Asiago Obs. No. 284.
Ap. J., 178, 1, 1972.
Ap. J., 183, 731, 1973.
Photometry (10 Color):
Ap. J., 179, 731, 1973.
IAU Circ. No. 2279, 1970.
Ast. Tsirk. No. 590, 1970.
Yamamoto Circ. No. 1726, 1970.
Mem. S.A. Ital., 44, 65, 1973 = Contr. Asiago Obs. No. 284.
E3 (de Vaucouleurs)
Paired with UGC 12531 at 6.9, 84
23 17.6 +07 53 = NGC 7617 at 2.8, 209, 0.7 x 0.5, S0 (de Vaucouleurs),
v = 4072, v(0) = 4269, m=15.1
Brightest in the Pegasus I Cluster.
Ap. J., 51, 304, 1920.
Dynamics and Mass:
Ap. J., 134, 262, 1961.
A.J., 66, 545, 1961.
4. NGC 7619 Group
This is a group of five galaxies which form part of the Pegasus cluster (Hubble
and Humason 1931; Edson and Zwicky 1941); they are the brightest members of it.
The group has been studied by Hodge (1961). The types and velocities are
NGC 7611 (S0), +3579 km/sec; NGC 7617 (S0), +5068 km/sec; NGC 7619 (E3), +3953
km/sec; NGC 7623 (E4), +3659 km/sec; and NGC 7626 (E1), +3553 km/sec. The group
has an approximate diameter of 3.5 X 10^5^ pc and the separations between the
galaxies are on the average greater than 220 kpc. Consequently, Hodge finds that
the virial theorem is satisfied only for galactic masses in the range
10^12^-10^13^ M_sun_ and mass-to-light ratios of the order of 300. There is some
difficulty in estimating the total population of the cluster containing the
brightest galaxies listed by Hodge. Probably the estimate by Zwicky (1959, p.
63) of about 60 members is the best. If the five that have been measured form a
good sample of the whole, and if the cluster has little central concentration,
as seems to be the case, then we may conclude that probably the whole group is
unstable, unless a considerable amount of dark material is present.