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Date and Time of the Query: 2019-06-20 T00:10:53 PDT
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Notes for object NGC 0424

10 note(s) found in NED.


1. 2009ApJ...696.1218Z
Re:NGC 0424
NGC 424. The broad H{alpha} and H{beta} lines were detected in polarized
emission by Moran et al. (2000). They report an H{alpha} FWZI of approximately
12,000 km s^-1^. However, since the broad lines are not detected in unpolarized
emission, we use the narrow-line [O III] flux, F[O III] = 4267.0 * 10^-16^ erg
s^-1^ cm^-2^ (Gu et al. 2006) to derive the bolometric luminosity.

2. 2007A&A...461.1209D
Re:Tololo 0109-383
Tololo 109-393: The Compton-thick nature (in the 2-10 keV energy band)
of the source was proposed in Matt et al. (2000a). The spectral
parameters presented here are well in agreement with those presented in
that paper and later confirmed using ASCA (Iwasawa et al. 2001),
XMM-Newton, and Chandra data (Matt et al. 2003).

3. 2004MNRAS.350.1049G
Re:Tololo 0109-383
9.2 Tol 0109-28 This Seyfert 2 galaxy has shown very little
activity. The colours of its variable components are considerably redder
than average, suggesting strong nuclear reddening. There appears to be a
delay of about 100 d between J and L.

4. 2000MNRAS.318..173M
Re:NGC 0424
2.7 TOLOLO 0109-383
Tololo 0109-383 (NGC 424) was observed by BeppoSAX on 1999 July 26-28 for
a net exposure time of 64 ks in the MECS and PDS, and 24.6 ks in the LECS.
The fit with the usual model gives a column density of about
2 x 10^24^ cm^-2^ (with the power-law index fixed to 2: the quality of the
data is not good enough to allow for a simultaneous estimate of both the
column density and the power-law index). The resulting intrinsic 2-10 keV
luminosity is 2 x 10^43^ erg s^-1^. Evidence for both cold and ionized
reflection components are present.
A complete analysis of the BeppoSAX data, along with those from a
previous ASCA observation, will be presented in Iwasawa et al. (in
preparation).

5. 2000ApJ...540L..73M
Re:NGC 0424
NGC 424.
As Figure 1 indicates, there is a distinct increase in the polarization
of this object near H{alpha}. The H{alpha} line in polarized flux is
very broad, with a full width near zero intensity (FWZI) of at least
12,000 km s^-1^, which is much broader than the FWZI of the narrow
[N II] + H{alpha} blend in the total-flux spectrum shown in the top
panel of Figure 1. There is clearly a broad component of H{alpha} in
the polarized-flux spectrum as well.

6. 2000ApJ...529..816M
Re:NGC 0424
T0109-383 (NGC 424) is a highly inclined (~75^deg^) early-type
[(R)SB(r)0/a; de Vaucouleurs et al. 1991] Seyfert galaxy at a distance
of 46.6 Mpc. The nucleus of T0109-383, originally classified as a
Seyfert type 2 (Smith 1975), exhibits strong line emission from highly
ionized species such as [Fe VII] {lambda}{lambda}5720, 6086 and
[Fe X] {lambda}6374 (Fosbury & Sansom 1983; Penston et al. 1984).
Analysis of the continuum emission from the far IR to the far UV and
decomposition of the H{alpha}-[N II] blend led Boisson & Durret (1986)
to suggest a reclassification of T0109-383 to a Seyfert 1. The recent
discovery of broad components to the H{alpha} and H{beta} lines, along
with emission from Fe II, confirms the type 1 classification (Murayama,
Taniguchi, & Iwasawa 1998). VLA images of the radio emission at 6 and
20 cm, show the nuclear radio source to consist of an unresolved core
with a flat spectrum ({alpha}_6_^20^ = 0.17 +/- 0.07) between {lambda}6
and {lambda}20 cm, and a weaker, secondary, steep spectrum component
~1.4" east of the core (Ulvestad & Wilson 1989). Similar radio structure
is seen in the 8.4 GHz VLA image (Braatz, Wilson, & Dressel,
unpublished), shown in Figure 1, with the core spectrum remaining
relatively flat ({alpha}_3.5_^6^ = 0.21) between 6 and 3.5 cm
(Morganti et al. 1999). The results of Gaussian fitting to the 8.4 GHz
VLBA image (Fig. 1), given in Table 2, show the subparsec-scale nuclear
emission to be unresolved, with a peak brightness of
T_B_ > 8.1 x 10^8^ K, adopting a source size smaller than half of the
beam size. The peak and integrated 8.4 GHz VLA fluxes for the core,
10.4 mJy beam^-1^ and 11.2 mJy, respectively, are in excellent agreement
with those measured from the VLBA image (Table 2), indicating that
little nuclear emission was missed by the VLBA. A similar peak brightness
of 10.4 mJy beam^-1^ is found in the 3.5 cm ATCA image of Morganti et al.
(1999), while their slightly higher integrated flux includes some of the
emission ~1" east and west of the nucleus (Ulvestad & Wilson 1989;
Fig. 1). The excellent agreement between the nuclear {lambda}3.6 cm
fluxes in observations spanning ~6 yr indicates no significant
variability.
In the VLBA image, we detected no extended emission in the
north-south direction (as might be expected from a parsec-scale, thermal
disk if the arcsec-scale, steep spectrum, east-west emission in the VLA
image is interpreted as emission from nuclear ejecta) brighter than
~1.3 x 10^6^ K (3 {sigma} in the naturally weighted image) and more
extended than 0.27 pc (half of the beam size in the naturally weighted
image).

7. 1999ApJS..120..209N
Re:NGC 0424
NGC 424 (type 2; Fig. 2) - The 20cm map clearly shows an extension
in a direction different from the beam extension. The deconvolved
source size is less than half the beam size; however, the extension in
P.A. 96^deg^ is probably real. The 20cm map in Paper VII, which is at
a higher resolution than our 20cm map, also clearly shows an extension
to the east. The central source in the 3.6cm image is unresolved. The
weaker source to the east appeared during the self-calibration
process. The P.A. joining the two sources is consistent with the
direction of the extension in the 20cm map. Our 3.6cm map is similar to
the 6cm map of the same source in Paper VII (where it is listed as
TOL 0109-383), in which the weak component to the east is also seen. We
classify this source as "S," and we adopt a radio P.A. of 96^deg^.
Paper VII commented on the flat spectrum of this source, {alpha} =
0.17 +/- 0.07 (S_{nu}_ is proportional to {nu}^-{alpha}^), between 6 and
20cm. Our measured flux of 12.2 mJy at 3.6cm confirms that the spectrum
of the core source is flat to even shorter wavelengths.

8. 1999A&AS..137..457M
Re:NGC 0424
TOL 0109-383 (NGC 424): This object has been observed by Ulvestad &
Wilson (1989) at 20 and 6 cm. With ~1" resolution they found a slightly
extended source with flux of 22.3 mJy at 20 cm, and 14.9 mJy at 6 cm. In
our data we also find a structure that is slightly extended to the east
(Fig. 5), although the very elongated beam of our observations makes
this very uncertain. Ulvestad & Wilson (1989) found that the dominant
component has a flat spectrum with a spectral index between 20 and 6 cm
of {alpha}_20_^6^ = -0.17. Our 3 cm measurement shows that the spectrum
remains flat between 6 and 3 cm, {alpha}_6_^3^ = -0.21.

9. 1988A&AS...75..273D
Re:TOLOLO 0109-383
TOL 0109-383 is an early-type Seyfert galaxy first observed
spectroscopically by Smith (1975). Its optical spectrum has been
analysed in detail by Fosbury and Sansom (1983, hereafter FS83), who
found a very high excitation level, with strong [FeVIII], [FeX] and
possibly [FeXIV] emission lines. The [FeX] emission was later
discussed by Penston et al. (1984), and line profiles in Tol 0109-383
were studied by Whittle (1985a and b). By analysing its overall far-IR
to far-UV continuum, together with the H{alpha}-[NII] blend, BD86 have
shown that in fact this galaxy was an obscured Seyfert 1.
We find a nuclear redshift z = 0.0117 + 0.0001, corresponding to a
heliocentric velocity of 3491 km s^-1^, and to a distance of 69.8
Mpc.
We have detected ionized gas over 14" (4.8 kpc), an extent similar
to that found through narrow band imaging by DB87.
The intensities of the emission lines detected in the UV are given
in table XV, together with those measured in the optical. The emission
line spectra of the nucleus and other regions of Tol 0109-383 are
shown in figure 13. The narrow H{alpha}/H{beta} ratio implies a large
amount of reddening, with E(B-V) in the range 0.7-1.16, and leads to
very high values of T_e_, from 40000 K to more than 60000 K. If the
reddening estimate E (B-V) = 0.5 derived from the [OII] and [SII] line
ratios by FS83 had been used throughout, the temperatures would have
been about 15% lower. The electronic density n_e_ for the low
ionization gas is only indicative, since it was derived from the [SII]
6717+6731/4070 line ratio, using the value of T_c_ estimated above.
Since the high and low ionization zones are probably distinct, n_e_
may have been overestimated by a factor of 2. However, our values are
comparable to the results of FS83 for the low ionization region (n_e_
= 8000 cm^-3^).
The relative emission line intensities observed in the nucleus agree
with those of FS83 within 50% except for the H{alpha}+[NII] blend
which we find larger (both data have comparable signal to noise
ratios).
Along PA = 242^deg^, the gas velocity in the central 12" (4 kpc)
region (including the nucleus and the zone south-west of it) is
roughly constant, with a variation of only 60 +/- 50 km s^-1^ over the
4 kpc. The region north-east of the nucleus has a velocity some 120 km
s^-1^ smaller.

10. 1985SGC...C...0000C
Re:NGC 0424
Plate 3524
Overexposed center and bar, very bright (r): 0.8 x 0.3, pretty
bright (R): 2.1 x 0.55.


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