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Notes for object NGC 3147

17 note(s) found in NED.


1. 2008MNRAS.390.1241B
Re:NGC 3147
4.2 NGC 3147 Our analysis of the XMM-Newton spectrum of NGC 3147 shows no
absorption above the Galactic column, however, it features a small (130 eV) iron
K{alpha} line at 6.4 keV. These results are in full agreement with those of
Bianchi et al. (2008). Bianchi et al. (2008) used the small EW of the iron
K{alpha} line to argue against the Compton thick nature of this source and came
to the conclusion that NGC 3147 has an intrinsic absence of a BLR. However, as
we have shown in IRASF 01475-0740, this conclusion is not necessarily robust.
Fitting the Monte Carlo models to the spectrum once again shows that a very
heavily obscured component is consistent with the spectrum. Here, the column
density is constrained to be N_H_= 9 * 10^23^|^+419^_-1.0_cm^-2^, with the main
constraint coming from the iron K{alpha} line. We can again use this second
component to predict the intrinsic luminosity of this source and calculate the
corresponding bolometric luminosity, which also agrees well with estimations
from L_[O III]_andL_12{mu}m_. Other evidence suggests, however, that this may
not be the correct interpretation in this case. The 2 ks Chandra observation of
NGC 3147 shows that the measured flux of the nucleus is ~2 times that measured
by XMM-Newton indicating that it is variable in nature and hence it must be
being observed directly, rather than in scattered light. Furthermore, the
Chandra imaging reveals no evidence for extra-nuclear X-ray sources that could
be producing the unabsorbed X-ray profile or the variability, and spectral
extraction from the nuclear region in the Chandra image does not reveal a
significantly harder X-ray spectrum then the larger XMM-Newton beam (Table 4).

2. 2008MNRAS.390.1241B
Re:NGC 3147
5.2.1 NGC 3147 NGC 3147 has no hidden BLR and a Chandra observation shows no
discernible extra-nuclear sources. Between observations by Chandra and
XMM-Newton, the hard X-ray flux drops by a factor of ~2 indicating that it is
variable in X-rays which means that we are likely to be seeing the nucleus of
NGC 3147 directly. Bianchi et al. (2008) carried out simultaneous optical/X-ray
observations of NGC 3147 to show that the apparent mismatch between optical and
X-ray classification was not due to differential variability. By noting a small
EW of the iron line and a large ratio between hard X-ray and [O III] fluxes,
they come to the same conclusion that the nucleus of NGC 3147 is genuinely
unobscured, and that this AGN must therefore intrinsically lack a BLR. We
cannot, however, rule out the Compton thick nature of this source without
observing it above 10 keV, where transmission from a Compton thick medium would
dominate.

3. 2008MNRAS.388..500E
Re:UGC 05532
UGC 5532 (NGC 3147). The H{alpha} emission is very weak in the nuclear region
and does not allow us to plot the rising part of the H{alpha} rotation curve
which rapidly reaches (within 1 kpc) a slightly decreasing plateau starting at
almost 400 km s^-1^. No H I velocity map is available. The width of the H I
profile at 20 per cent (455 km s^-1^ from Richter & Huchtmeier 1991, and 403 km
s^-1^ from Lang et al. 2003) is in agreement with our H{alpha} velocity field.

4. 2007A&A...461.1209D
Re:NGC 3147
NGC 3147: The X-ray spectrum of this source is similar to that of
NGC 3079. The PDS did not detect the source above 10 KeV. For this
reason it is not possible to firmly assess its Compton-thick nature
unless assuming that the column due to the putative dusty torus is
higher the ~10^25^ cm^-2^, thus preventing any possibility of the
primary emission penetrating it.

5. 2005ApJ...627..674A
Re:NGC 3147
NGC 3147.This galaxy was unresolved in the VLBA imaging of Ulvestad & Ho
(2001b) and A04.

6. 2003ApJ...583..145T
Re:NGC 3147
NGC 3147 (S2). This object was observed with ASCA in 1993 September,
and the observed flux was 1.6 x 10^-12^ ergs s^-1^ cm^-2^ in the 2-10
keV band (Ptak et al. 1996, 1999; Terashima et al. 2002). Our Chandra
image is dominated by the nucleus and shows that the off-nuclear
source contribution within the ASCA beam is negligible. Therefore, a
comparison between the observed Chandra flux (3.6 x 10^-12^ ergs s^-1^
cm^-2^), which is 2.3 times larger than that of ASCA, implies time
variability, providing additional evidence for the presence of an AGN.
.
In the ASCA spectrum, a strong Fe-K emission line is detected at
6.49 +/- 0.09 keV (source rest frame) with an equivalent width of
490 +220/-230eV. One interpretation of this relatively large
equivalent width is that the nucleus is obscured by a large column
density and the observed X-rays are scattered emission (Ptak et al.
1996). However, the luminosity ratios LX/L_H{alpha}_ and LX/L_[O III]_
5007 suggest small obscuration (Terashima et al. 2002).
.
The observed variability supports the interpretation that the X-ray
emission is not scattered emission from a heavily obscured nucleus.
This galaxy is an example of a Seyfert 2 galaxy with only little
absorption in the X-ray band.

7. 2002ApJS..139....1T
Re:NGC 3147
NGC 3147 (S2).-A detailed analysis of the ASCA data is given in Ptak et
al. (1996). We confirmed their detection of a strong Fe K emission
line. Although this object is optically classified as a Seyfert 2
galaxy, no strong absorption is seen in the X-ray spectrum. The
relatively strong Fe K emission line (EW = 490^+220^_=230_ eV) could be
an indication that the observed X-rays are scattered emission and that
the nucleus is obscured below 10 keV. However, the L_X_/L_H{alpha}_
ratio (32) falls in the range of unobscured AGNs. The ratio of X-ray to
[O III] {lambda}5007 luminosity is also typical of those observed in
Seyfert 1 nuclei (Bassani et al. 1999). Some LLAGNs with low absorption
in our sample also show similarly large EWs for the Fe line (~300 eV).
For example, the X-rays from NGC 4579 (EW = 490 eV) and NGC 5033
(EW = 306 eV) must be dominated by direct emission because the sources
are variable. This suggests that NGC 3147, too, could be largely
unobscured. Future observations to search for variability or emission
lines due to a scattering medium are crucial to distinguish between
these two competing possibilities.

8. 2001ApJS..133...77H
Re:NGC 3147
NGC 3147 (S2). - Several investigators have observed this galaxy at ~1"
resolution at 6 cm and find a compact, ~10 mJy core (Heckman et al. 1980;
van der Hulst et al. 1981; Vila et al. 1990; Laurent-Muehleisen et al.
1997), consistent with our measurements. Vila et al. (1990) report
S_20_ = 10.6 mJy, also in good agreement with our value. The 6 cm core
shows weak, but significant, linear polarization (Fig. 16f); the peak
signal, S_pol,6_^P^ = 0.23 mJy beam^-1^, is approximately 10 times the rms.
Polarization is not detected at 20 cm (S_pol,20_^P^ < 0.11 mJy beam^-1^).

9. 2001A&A...368...16M
Re:NGC 3147
15. NGC 3147 is an Sb spiral of low inclination (Q_disk_ = 0.84,
PA_disk_ = 150^deg^). The bulge has a similar axis ratio, but appears at a
very different position angle PA_bulge_ = 88^deg^. Since it is not
plausible that the different orientations of the (projected) major axes of
disk and bulge are due to a different plane of symmetry, the bulge must be
triaxial. NGC 3147 is one of the rare examples with such a feature. Most
triaxial bulges seen on visual images are artefacts of dust absorption and
disappear in the NIR.

10. 2000ApJ...542..186N
Re:NGC 3147
NGC 3147.-Vila et al. (1990) find S_20 cm_^peak^ = 10.6 mJy beam^-1^
and S_6 cm_^peak^ = 8.55 mJy beam^-1^ at resolutions of ~1.2" and ~1.5",
respectively, with both maps showing only a compact core. Consistent
with this, Laurent-Muehleisen et al. (1997) find a nuclear peak flux
density of 9 mJy beam^-1^ at 6 cm at a resolution of 0.4". Combining
this 6 cm flux density with our 2 cm peak flux density (8 mJy beam^-1^),
the nonsimultaneous spectral index of the emission in the central 0.4"
is flat, {alpha}_2_^6^ >= 0.

11. 1998AJ....116.2682C
Re:IRAS 10126+7339
NGC 3147. Seyfert 2.

12. 1994CAG1..B...0000S
Re:NGC 3147
Hubble Atlas, p. 20
Sb(s)I-II
PH-7961-S
Nov 8/9, 1980
103aO
12 min
The spiral pattern in NGC 3147 is similar
to that in NGC 488 (Sab; panels 115, 116, S3,
S12), but the star-formation rate is higher in the
arms and the smooth bulge is smaller. The arm
pattern consists of spiral fragments that can be
traced as individual continuous segments without
branching for only about one-quarter turn. The
largest HII regions in the arms have angular
diameters of about 3".

13. 1976RC2...C...0000d
Re:NGC 3147
SN1972H:
IAU Circ. No. 2381, 1972.
IAU Circ. No. 2382, 1972.
IAU Circ. No. 2431, 1972.
IAU Circ. No. 2334, 1972.
IAU Circ. No. 2352, 1972.
Ast. Tsirk. No. 670, 1972.
Ast. Tsirk. No. 700, 1972.
Ast. Tsirk. No. 716, 1972.
Ast. Tsirk. No. 723, 1972.
Astr. Ap., 29, 57, 1973. (with photograph)

14. 1973UGC...C...0000N
Re:UGC 05532
SA(rs)bc (de Vaucouleurs)

15. 1964RC1...C...0000d
Re:NGC 3147
Very bright nucleus. Many filamentary narrow arms in a lens. No definite
(r) structure
Heidelberg Veroff. Vol. 9, 1926 dimensions (2.0 arcmin x 1.7 arcmin) are
for the bright part only.

16. 1961Hubbl.B...0000S
Re:NGC 3147
Sb
S-1910-H
Jan. 27/28, 1946
103aO
60 min
Enlarged 8.2X
This galaxy is similar to NGC 6814. Tightly wound multiple
arms are present, which can be traced to within 8 sec of
arc (2.5 mm on the illustration) from the small, amorphous
nucleus. The details of the structure are not too
clear on this reproduction from a poor 60-inch plate.
The arms are highly branched. Note the faint-surface-
brightness arm on the outside of the bright arm on the
north side. Whenever two arm systems of different surface
brightness occur, the fainter set is always on the
outside.

17. 1918PLicO..13....9C
Re:NGC 3147
A nearly round, rather symmetrical and open spiral 3' in diameter; numerous
almost stellar condensations. The nucleus is almost stellar and very bright,
showing well in 10m, exposure. There is now no trace of the suspected nova noted
by Mrs. Roberts in A. N., 4708, 197, 1914, 5' 16" west and 1' 58" north of the
nebula. The position given is far outside of the faintest extensions of this
spiral. 2 s.n.


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