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Notes for object MESSIER 106

35 note(s) found in NED.


1. 2007ApJS..173..538T
Re:NGC 4258
NGC 4258 [M 106] (Fig. 16.19).-GALEX observations of this SAB(s)bc; LINER
Seyfert 1.9 galaxy indicate a very large extent (~25'), although the substantial
inclination of the disk (and the orientation of its warped outer H I) make it
difficult to say precisely to what galactocentric distance XUV features are
seen. The most significant area with XUV-disk clumps is south of the disk. SDSS
data detect very few of these star clusters. NGC 4258 is the brightest galaxy in
a group having over 20 members, possibly interacting with NGC 4248 (f = -2.2).

2. 2007AJ....134..648M
Re:NGC 4258
NGC 4258 (M106; Figs. 7.21, 9.21, 20.21): The compact nucleus is resolved
in our observation. There are many stellar clusters that can be studied
individually, and there is a vast amount of absorption by dust in the
southwest half of the image. This galaxy hosts a water-masing disk that
led to the second-best determination of the mass of a supermassive black
hole (SMBH) after the one in the Milky Way (Miyoshi et al. 1995).

3. 2006A&A...452..739S
Re:NGC 4258
X6 in NGC 4258.
The nearby and almost edge-on barred (SAB(s)bc) galaxy NGC 4258 (Messier 106)
hosts a weak AGN. It also forms a pair with NGC 4248 in the Ursa Major Cluster.
The optical image (see electronic Fig. 3) shows an apparent chain of HII regions
at the extremities of its arms. This galaxy is well known for its nuclear thin
disk in Keplerian rotation, which is traced by emission from water masers
(Miyoshi et al. 1995) and implies a supermassive central black hole.
This case is reminiscent of the first object discussed above, both in flux
density level and galactocentric distance. The radio morphology suggests a
core+jet structure with the brighter component being consistent with the X-ray
position. Again, we speculate that this object is most likely a background QSO
unrelated to the galaxy.

4. 2005ApJS..160...76B
Re:NGC 4258
Typical discordance and excellent S/N. Clearly defined rotation and an irregular
{sigma}_*_ field. NGC 4258 is inclined at [IMAGE]72{degree} and exhibits a
dust lane (Hughes et al. 2003). The curve of growth shows a steep drop
toward the center. See Figures 23 and 25c.

5. 2005ApJS..157...59L
Re:NGC 4258
NGC 4258 (M106) is a large barred Sbc spiral galaxy at the distance of 7.727
Mpc, which hosts a weak Seyfert 2 nucleus. ULX1 is on the edge of a spiral arm,
and ULX2 is on a thin spiral arm. The luminosities of both ULX1 and ULX2 changed
from below 0.3 * 10^39^ to ~1.6 * 10^39^ ergs s^-1^ in 500 days. ULX1 showed
variability during an 20 day observation.

6. 2004A&A...418..877A
Re:NGC 4258
NGC 4258 is a Seyfert II galaxy with "anomalous" spiral arms. The
distance used to compute the X-ray emission is 6.4 Mpc. This is a very
interesting case in which three of the X-ray sources listed by Pietsch
et al. (1994) have result quasars at higher redshift than the parent
galaxy. The angular distance of these three objects with respect to
NGC 4258 is very similar, with two of them (the objects with redshifts
0.398 add 0.653 lying nearly along the minor axis of NGC 4258. More
details about these sources can be found in Pietsch et al. (1994);
Burbidge (1995); Vogler & Pietsch (1999) and Mirioni (2003).

7. 2003ApJS..146..353M
Re:NGC 4258
NGC 4258 (HI)
The inclination of this galaxy is too high to classify the
circumnuclear dust structure. It is also sufficiently nearby that the
giant stars are resolved, which gives the color map its mottled
appearance. The V-I color map shown in Pogge et al. (2000) is less
affected by resolved stars.

8. 2003ApJS..146..249B
Re:NGC 4258
5.10. NGC 4258
The maser in NGC 4258 has been monitored by Haschick et al. (1994),
Greenhill et al. (1995), and Bragg et al. (2000). We have not
monitored this source as part of our program, but we do present a GBT
spectrum in Figure 2. In the triply peaked structure of the maser in
NGC 4258, the systemic masers are clearly the brightest. A similar
relative strength of components is apparent in IC 2560. However, if
the negligible velocity drifts in the masers of other detected
galaxies indicate that they are analogous to the high-velocity lines
in NGC 4258, then the high-velocity lines are dominant in these
galaxies.

9. 2003AJ....126..742H
Re:NGC 4258
The morphological classification as determined by us is indicated in
parentheses next to the galaxy name, with our "chaotic circumnuclear
dust" (C) category now not including those galaxies with obvious dust
lanes (DL). Where the classification has already been made by Martini
et al. (2003), we indicate this with "-mp."
.
3.24. NGC 4258 (DL)
Figure 12 (top).
Spectra: Broad emission lines on NUC spectrum, with little extended
emission. Lines are less broad in OFF spectra, but more extended
emission is present.
Images: Smooth profile, with dust lane to the northeast of the
nucleus.

10. 2002ApJS..139....1T
Re:NGC 4258
NGC 4258 (Part 1)(S1.9).-We analyzed four ASCA observations obtained in 1993
and 1996. Makishima et al. (1994) reported the discovery of an obscured
X-ray nucleus using the 1993 observation; Ptak et al. (1999) also
discussed the same data set. We reanalyzed this data set in greater
detail, as well as three others taken in 1996. Reynolds, Nowak, &
Maloney (2000) performed a deep (~200 ks) observation in 1999.
The ASCA spectrum from 1993 is very complex. In the following
fits, we assume the Galactic absorption column density for the soft
thermal components. We examined the canonical model which consists of
a soft thermal plasma and a hard component. This simple model failed to
explain many of the emission lines seen in the region 0.5-3 keV as well
as the broadband continuum shape. A single-temperature fit to the
soft X-ray spectrum resulted in kT~ 0.65 key, but residuals remained
near the locations of the H-like O K, He-like and H-like Mg K, and Fe L
emission lines in the 0.7-1.4 keV region. This suggests that the plasma
has multiple components, with temperatures cooler and hotter than 0.65
keV, or that a temperature gradient is present. Therefore, we tried a
model composed of a two-temperature RS plasma plus a hard component.
This model gave a better fit to the soft thermal emission. However,
systematic convex-shaped residuals remained in the 3-10 keV region,
which can be attributed to a deficit in the model around 2-3 keV and to
an N_H_-value too small and a photon index (for the hard component) too
steep at the {chi}^2^ minimum. A satisfactory fit can be achieved with
a model consisting of a two- temperature RS plasma, a thermal
bremsstrahlung component, and an absorbed power law. The abundances of
the two RS components were assumed to be identical. The temperature of
the thermal bremsstrahlung component was fixed at 4 keV. An Fe line is
seen at 6.66^+0.20^_-0.07_ keV (source rest frame) with
EW = 108^+73^_-64_keV. The spectral parameters for the AGN continuum
are consistent with those derived by Makishima et al. (1994) based on
the GIS data only. Note that Ptak et al. (1999) used the canonical
model and obtained a photon index of ~1.2 and N_H_ 7 ~ 10^22^
cm^-2^. This model resulted in significant systematic residuals (see
Figs. 2q and 2r in Ptak et al. 1999), suggesting that the true photon
index should be steeper and N_H_ larger.

11. 2002ApJS..139....1T
Re:NGC 4258
NGC 4258 (Part 2). The complicated soft thermal emission in NGC 4258
is probably due to the superposition of its extended galactic halo
and interstellar medium, which is shock heated by the complex system
of jets emanating from the nucleus (Pietsch et al. 1994; Cecil, Wilson,
& De Pree 1995). A possible origin for the medium-hard emission we
modeled with a kT = 4 keV thermal bremsstrahlung component might be
the integrated emission from low-mass X-ray binaries. Future X-ray
spectroscopy with better spatial resolution will be able to resolve
these multiple X-ray emission components (see, e.g., Wilson, Yang,
& Cecil 2001 for a Chandra image).
NGC 4258 was observed three times in 1996 (see Table 2). We fitted
the combined spectrum of these three data sets, after discarding the
low-energy (<0.7 keV) portion of the SIS data to minimize calibration
uncertainties. The ASCA spectrum is well fitted with the canonical
model. The flux of the hard component is about twice that observed in
1993, and the energy band above 2 keV is now dominated by the AGN
emission. This variability provides additional evidence for the
presence of an LLAGN. The medium-hard component introduced to fit the
1993 spectrum was not required for the 1996 data. The soft component can
be represented by a single-temperature RS model, in contrast to the 1993
result. This is probably attributable to (1) the degraded energy
resolution of the SIS, (2) the limited energy band used in the spectral
fits, and (3) the brighter hard component in 1996. The absorption column
for the AGN component decreased from N_H_ = 1.3 x 10^23^ cm^-2^ in 1993
to 7 x 10^22^ cm^-2^ in 1996. An Fe emission line is detected at
6.31^+0.09^_-0.10_ keV (source rest frame) with EW = 54^+25^_-27_ eV.
The line centroid energy decreased from 6.66 keV to 6.31 keV in the
interval of 3 years, while the continuum luminosity increased during the
same period. A similar behavior of Fe line variability has been reported
for NGC 4579 (Terashima et al. 2000c). The Fe line energy and EW measured
by BeppoSAX are 6.57 +/- 0.20 keV and 85 +/- 65 eV, respectively, but
it is unclear whether these values are different compared to those
measured with ASCA.

12. 2002ApJ...574..740T
Re:NGC 4258
NGC 4258.
The velocity dispersion is obtained from Heraudeau & Simien (1998).

13. 2002AJ....124..675C
Re:UGC 07353
Very large galaxy; the NVSS flux is too low. Seyfert 1.9. Anomalous
radio arms. Starburst/AGN combination.

14. 2002A&A...389...68G
Re:NGC 4258
NGC 4258: as our two methods are in agreement for this quite inclined
galaxy we adopt their mean value which is in agreement with the
results of the velocity fields of van Albada (1980) and
van Albada & Shane (1975).

15. 2002A&A...386..379R
Re:NGC 4258
NGC 4258: NGC 4258 is a nearby galaxy (estimated
distance ~7 Mpc) hosting a weak AGN. In this object the
integrated X-ray emission of galactic sources is not
negligible with respect to the AGN contribution. Therefore,
in models B and C we added an extra bremmshtralung component
to take into account for the galactic contribution. The best
fit temperature (kT=7 keV) and normalization are in agreement
with those estimated in 5 different measures performed with
ASCA (Reynolds et al. 2000). Our results is in agreement
with the more detailed analysis of the same data performed
by Fiore et al. (2001).

16. 2001ApJS..137..139S
Re:NGC 4258
NGC 4258 (M106). - Herrnstein et al. (1999) derive a geometric distance
of 7.2 Mpc for a distance modulus of (m - M)_0_ = 29.29.

17. 2001ApJS..136...61S
Re:NGC 4258
5.21. NGC 4258 (=M106)
NGC 4258 contains a nuclear thin disk in Keplerian rotation, traced by
emission from water masers (Miyoshi et al. 1995). The implied enclosed mass
density, 3.6 x 10^7^ M_sun_ within 0.14 pc of the nucleus
(Herrnstein et al. 1996), is consistent with a supermassive central
black hole. In spite of the clear presence of a nuclear black hole,
NGC 4258 is a relatively inactive system. Both the nuclear H{alpha} and
radio continuum luminosities are low, and the nucleus was originally
undetected in X-ray observations made with the Einstein Observatory
(Ford et al. 1986 and references therein). Subsequent observations with
ASCA have revealed a low-luminosity obscured active nucleus (Makishima
et al. 1994), and Filippenko & Sargent (1985) have observed very weak
broad H{alpha} emission. Our K-band image (see Fig. 3) shows an unresolved
central source, and recently Chary et al. (2000) have shown this source to
be unresolved down to 0.2" FWHM resolution. These authors have also fitted
their NIR flux densities with a single, nonthermal, power law
({nu}^-1.4+/-0.1^), using a foreground screen extinction correction
corresponding to an A_V_ of 18 mag.

18. 2001ApJS..133...77H
Re:NGC 4258
NGC 4258, M106 (S1.9). - At the scale of our images, the nucleus of
NGC 4258 appears as a slightly resolved 2-3 mJy core with a somewhat flat
spectral index of {alpha}_6_^20^ = -0.18, in agreement with previous
observations from 2 to 20 cm at similar resolution (Vila et al. 1990;
Saikia et al. 1994; Turner & Ho 1994). Our 20 cm map shows low-surface
brightness emission extending to the northwest and southeast. These belong
to the complex set of "anomalous radio arms" best seen in the
{DELTA}{theta} = 6.5" 20 cm VLA+WSRT image of van Albada & van der Hulst
(1982). On VLBI scales, the central core breaks up into a subparsec jet
oriented along the axis of the water maser disk (Herrnstein et al. 1997,
1998). The continuum source at 22 GHz varies by a factor of 2 on a
timescale of weeks (Herrnstein et al. 1997).

19. 2001AJ....122..637H
Re:NGC 4258
NGC 4258. - A number of sources in the vicinity of this object were
investigated by Vogler & Pietsch (1999). In an attempt to isolate nuclear
counts, they extract counts from a very small central region (of radius
24", corresponding to the FWHM of the on-axis PSPC PSF at 1.0 keV), and
subtract off a local background. Their best-fit model for the spectrum of
the nuclear region consists of a thermal bremsstrahlung with kT = 0.63 keV.
Their resulting flux is very close to the nuclear flux that we estimated by
lowering the total flux by the fraction included in a theoretical point
source (see section 4.1).

20. 1999ApJ...526L...9P
Re:NGC 4258
This is a Seyfert 2 galaxy for which Miyoshi et al. (1995) measured,
using H2O masers, the rotation curve of a circumnuclear disk with an
inner radius of 0.13 pc. According to Miyoshi et al. (1995), this disk
is at an inclination relative to the line of sight (+/-{phi}) of
i_disk_ = 83^+4^_-4_ degrees. The inclination of the host galaxy is
i = 72^deg^, and the major axis P.A. is 148^deg^, determined by van
Albada (1980) using H I kinematical data. Herrnstein et al. (1997)
observed that the radio jet lies along P.A. = 0^deg^, which gives
{delta} = 32^deg^. We find that, by inspection of the Digitized Sky
Survey image, the west side of the galaxy is the nearer one, so the jet
is projected against the farthest side of the galaxy. Using equation (3)
and these values, we find {beta} ~ 57^deg^. Note that the innermost ring
at which the maser measurements are possible corresponds to several
thousand Schwarzschild radii. We should bear in mind that the very inner
disk at a few Schwarzschild radii (where the Fe K {alpha} is emitted)
might not be aligned with the disk at larger radii.

21. 1999AJ....118.2331V
Re:NGC 4258
One pair each of a medium-band F547M and narrow-band F658N
(H{alpha}) and F502N ([O III]) image of NGC 4258 is available. SN was
not spectroscopically classified, but is very likely a Type II, based on
the properties of its radio emission (Van Dyk et al. 1992). It appears
to have occurred along the edge of the northeast arm in this galaxy,
near several large H II complexes (Fig. 3a). Given the observed
correlation of radio emission in SNe II with late-time optical emission
(Chevalier & Fransson 1994), we might expect SN 1981K to have still been
a relatively luminous optical emission source in 1995, when these images
were made. A very faint pointlike source of possible H{alpha} emission
is seen near the bottom of the error circle, with m_F658N_ = 22.52 +/-
0.30 mag (adopting the STMAG zero point from Holtzman et al. 1995; their
Table 9), which could be SN 1981K (or, possibly, a faint H II region).
Using the online "WFPC2 Exposure Time Calculator" to convert a
point-source count rate into flux, we find F_H{alpha}_ = 2.0 x 10^-17^
ergs cm^-2^ s^-1^. For a distance to NGC 4258 of 7.3 Mpc (Herrnstein et
al. 1997), this corresponds to a luminosity of L_H{alpha}_ = 1.0 x
10^34^ ergs s^-1^ (not corrected for reddening). For comparison, Fesen
et al. (1999) recently estimated the dereddened late-time H{alpha}
luminosity for SN 1979C to be L_H{alpha}_ = 1.5 x 10^38^ ergs s^-1^.
If this is not the SN, but instead an unrelated emission source in
the environment, then we can place an upper limit on the H{alpha}
emission at the position of the SN: F_H{alpha}_ < 2.5 x 10^-18^ ergs
cm^-2^ s^-1^, or L_H{alpha}_ < 1.2 x 10^33^ ergs s^-1^.
We see from Figure 3b that the [O III] emission in the field
appears to be particularly associated with the cores of the bright H II
complexes. The [O III] emission within the error circle, even at the
position of the faint H{alpha} source, is extremely faint. If the
H{alpha} emission is from SN 1981K, the relative lack of [O III]
emission would be consistent with the shock/circumstellar matter
interaction model by Chevalier & Fransson (1994).
Figure 3c shows the continuum counterpart of the faint H{alpha}
source, as well as some associated nebulosity or unresolved stars. The
source has m_F547M_ = 22.36 +/- 0.08 mag or, for the distance modulus
m - M = 28.85, M_V_ ~ -6.5. A nearby small cluster of stars can also be
seen inside the northwest edge of the error circle. The brighter stars
among them have m_F547M_ = 23.07 +/- 0.18, 22.84 +/- 0.08, and
23.32 +/- 0.20 mag; the faint star nearby has m_F547M_ = 24.26 +/- 0.22
mag. These stars have M_V_ ~ -5.8, -6.0, -5.5, and -4.6 mag,
respectively. Although we do not have any color information for this
environment, these magnitudes are consistent with those of supergiant
stars. The fact that little H{alpha} emission is associated with these
stars implies that they are nonionizing, cooler, possibly yellow or red
supergiants. Thus, SN 1981K may be associated with a population of
evolved supergiants, with no recent star formation occurring in its
immediate environment. Given that the radio emission for the SN
possibly arises from the SN shock interacting with the progenitor's red
supergiant wind(Van Dyk et al. 1992), this would also imply that the
SN's progenitor was a red supergiant of relatively low mass
(M >~ 8 M_sun_).

22. 1999A&AS..136...35S
Re:MESSIER 106
M 106 -- Castellanos et al. (1998) point out the presence of broad
He II {lambda}4686 in the brightest HII region of this Seyfert 2
galaxy.

23. 1998ApJS..114...59L
Re:NGC 4258
NGC 4258 (M106).--This is one of Heckman's original two transitional objects.
Its optical line ratios are actually typical of Seyfert galaxies. Its infrared
spectra are similar to those of NGC 3998; there is only a fairly weak detection
of [Fe II] in emission. It also has a ratio of [Fe II] to Pa{beta} of 0.6,
which is low for this sample, but is similar to that of NGC 3998. Optically, it
is also very similar to NGC 3998, with faint broad wings of H{alpha} and
slightly broadened O I. The Na absorption feature is detected weakly. Unlike
NGC 3998, NGC 4258 shows several strong optical absorption features (Filippenko
& Sargent 1985). A wealth of high-resolution observations have focused on
NGC 4258, which show it to have a rotating ring of water masers (see, e.g.,
Nakai, Inoue, & Miyoshi 1993), optical jets (see, e.g., Ford et al. 1986), and
a steeply rising velocity curve (Miyoshi et al. 1995), all of which make
NGC 4258 one of the best candidates for harboring a central black hole. Its
[Fe II] and H_2_ ratios are comparable to those of Seyfert galaxies.

24. 1998A&AS..128..153M
Re:GB1 1216+475
M106; NGC4258; UGC7353. Low-luminosity, starburst galaxy with a
trace of non-thermal nucleus. References to WSRT and Effelsberg
maps, as well as physical parameters in
Condon & Broderick (1988AJ.....87.1064C)

25. 1997ApJS..112..391H
Re:NGC 4258
NGC 4258.--With [O III] {lambda}5007/H{beta}~10, NGC 4258 (M106) harbors a
Seyfert nucleus (Paper III), not a LINER (see, e.g., Heckman 1980; Greenhill et
al. 1995). VLBI observations recently have furnished dynamical evidence that
the nucleus has an extremely high mass density, probably indicative of a
supermassive black hole (Miyoshi et al. 1995; Greenhill et al. 1995). A broad
H{alpha} component is apparent in the high-resolution nuclear spectra published
by Stuwe, Schulz, & Huhnermann (1992; see their Fig. 2), although the detailed
shape of the H{alpha}+[N II] complex is somewhat different from ours (Fig. 11h)
because these authors did not correct their data for starlight contamination.
Stuwe et al. questioned the reality of the broad H{alpha} line, arguing that
Lorentzian profiles alone, instead of Gaussians, can give an acceptable fit to
the complex without invoking an extra broad component. But, as we have shown
throughout this paper, any single analytic profile, whatever its form,
generally gives a poor representation of the intrinsic shapes of the narrow
lines, and a more involved procedure must be applied. Using a model for the
narrow lines derived from the [S II] profile, a very pronounced broad H{alpha}
component, as was previously noticed by Stauffer (1982) and Paper I, is
inferred from our fit (Fig. 11h). The narrow lines have an obvious blue
asymmetry and have FWHMs of about 290 km s^-1^. The broad H{alpha} component
can be represented reasonably well by a Gaussian of FWHM~1700 km s^-1^, from
which we deduce a luminosity (not corrected for extinction) of 4.5x10^38^
ergs s^-1^ (assuming a distance of 6.8 Mpc; Tully 1988). Note that Wilkes et
al. (1996) found that the polarized spectrum of the nucleus exhibits emission
lines that are broader than those in the unpolarized spectrum. The broad lines
in this case, however, only have FWHM~1000 km s^-1^ and are seen both in the
permitted lines and in the forbidden lines. This component, therefore, is
different from the broad component we observe associated with H, which we
attribute to the classical BLR. A weak broad H{alpha} component may be present
in the polarized spectrum of Wilkes et al., but the S/N of their data does not
permit a clear determination.

26. 1997A&A...319...33A
Re:NGC 4258
NGC 4258 (Fig. 2) The pair of X-ray sources with C=9.9 and 5.6 were discovered
by Pietsch et al. (1994) and identified as blue stellar objects. E.M. Burbidge
(1995) later confirmed them as quasars of z=.398 and .653. The sources in the
other pair with C=4.0 and 8.8 fall on either end of the major spiral arms of
NGC 4258. Blue sensitive plates with the 200-inch Palomar reflector which are
available show three stellar objects, mpg~21, within a 24" error circle for the
northern X-ray source and four candidate objects, two ~18mag. and two ~21 mag.,
near the southern X-ray source. It would require observations with a large
aperture telescope to attempt their identifications. It can be seen from the
table of Seyferts listed by Radecke in the preceding paper that the optical
dimensions of the galaxy include these last discussed sources. This would make
it even more important to investigate what relation, if any, these sources bear
to the sources displaced outside the optical limits of the galaxy.
NGC 4258 shows a clear "cross" pattern of sources, with one pair oriented
almost 90^deg^ with respect to the other. This configuration is seen frequently
(e.g. NGC 4594) and several other examples are seen among the maps shown in
Figs. 2-13. This cross pattern of sources has also been seen in PSPC maps
around bright quasars (Arp 1995c). It should also be noted in the X-ray map of
NGC 4258 that there are three fainter sources aligned nearly N-S through the
nucleus.

27. 1994CAG1..B...0000S
Re:NGC 4258
Sb(s)II
Hubble Atlas, p. 33
PH-321-MH
April 27/28, 1951
103aO
30 min
NGC 4258 is a nearby galaxy, well resolved
into individual stars and HII regions in its two
main outer, low-surface-brightness arms.
Very-high-surface-brightness inner arms exist,
containing a number of high-surface-brightness HII
regions.
The resolution into individual stars is less
complete than in either M81, with a distance
modulus of m - M = 27.7, or in M101 whose
distance modulus is m - M = 29.3. The resolution
is more complete than for spirals in the Virgo
Cluster (m - M = 31.7). Based on these data, the
modulus of NGC 4258 is about m - M = 30. The
redshift is small at v_o = 520 km/s, which, in the
absence of very local streaming motions within
10 Mpc (Sandage 1975b, 1986a), is consistent
with a local Hubble constant of 50 km/s Mpc^-1^

28. 1994CAG1..B...0000S
Re:NGC 4258
Sb(s)II
Hubble Atlas, p. 33
PH-96-S
Jan 3/4, 1952
103aO + WG2
30 min
The region interior to the two bright inner
luminous arms in NGC 4258 is filled with dust,
which forms semi-spiral chaotic patterns, seen
well in silhouette against the central bulge
because of the high inclination angle. A negative
print by Hubble (1943) shows the dust pattern
well.
The largest of the many HII regions in the
inner arms has a core diameter of 8" and a halo
diameter of 13". At a distance of 10 Mpc these
linear diameters of 390 pc and 630 pc, with a
mean diameter of 510 pc, are consistent with a
calibration of HII size with galaxy luminosity
class given elsewhere (Sandage and Tammann
1974 a).

29. 1993ApJS...86....5K
Re:NGC 4258
NGC 4258 (M 106); SBc, LINER.
This bright, barred spiral galaxy contains two anomalous arms of H{alpha}
emission in its inner regions, which also emit in the radio. The radio
emission is nonthermal in origin and probably due to the ejection of
matter or an explosive event in the nucleus, according to Krause, Beck, &
Klein (1984). Based on the strengths and ratios of the optical emission
lines, this galaxy has been classified as a LINER, approaching the
Seyfert domain (Heckman 1980). The UV continuum does not manifest strong
nuclear nonstellar emission. The blue rising branch of the UV, the broad,
deep absorption features, and the nebular emission line of C III]
{lambda}1909 are all characteristic of H II regions. Ellis et al. (1982)
find that NGC 4258 is dominated by B stars, with little contribution from
O stars. Barbon, Capaccioli, & Longo (1984) suggest that the UV continuum
can be explained by several bursts of star formation at different stages
of their evolution. The short- and the long-wavelength spectra do not
match up, most likely because the position angles of the 10" X 20" IUE
aperture are not the same.

30. 1985ApJS...57..643D
Re:VV 448
Asymmetric spiral.
See van der Kruit, P. C., Oort, J. H., and Mathewson, D. S.
1972, Astr. Ap., 21, 169.

31. 1977A&AS...28....1V
Re:VV 448
Plate 14 Stages of Gemmation and "Twice M51 Type Galaxies".
MCG +08-22-104 = NGC 4258; 8.90m in H{alpha} (van den Kruit 1974).
Strong H II condensations at the extremities of the arms. V_0_=+530
(RC1); v=9.61, B-V=0.82, U-B=0.24.

32. 1976RC2...C...0000d
Re:NGC 4258
= Holm 363a
Pair with NGC 4248 at 13.3 arcmin
Description and Structure:
IAU Symp. No.58, 392, 1974.
Photograph:
Ap. J., 149, 487, 1967.
Astr. Ap., 9, 181, 1970.
Astr. Ap., 21, 169, 1972.
Mem. S.A. Ital., 44, 417, 1973 = Cont. Asiago, No. 301.
IAU Symp. No.58, p.391, 1974.
Photometry (5 Color):
A.J., 73, 313, 1968.
Photometry (UBVRI):
A.J., 73, 866, 1968.
Blue Isophotometry:
Mem. S.A. Ital., 44, 417, 1973.
Spectrum and Internal Motions:
Ap. J., 149, 487, 1967.
Ap. J., 192, 1, 1974.
Spectrophotometry:
Sov. A.J., 13, 593, 1970.
Polarization:
Astrofizika, 4, 409, 1968.
Rotation Curve and Mass Determination:
A.J., 71, 157, 1966.
J. Observateurs, 48, 247, 1965 = Publ. O.H.P., 8, No. 16.
Bol. Tonantzintla, 4, No. 26, 1965.
Ap. J., 192, 1, 1974.
Interfeometry H{alpha}.
Astr. Ap., 9, 181, 1970.
C.R.Acad. Sc.,Paris, B, 275, 759, 1972.
HI 21cm:
Ap. J., 150, 8, 1967.
Radio Observations:
Ap. J., 122, 1333, 1965.
Astr. Ap., 21, 169, 1972.
IAU Symp. No.58, pp.380, 390, 1974.
Proc. 1st Eur. Ast. Meet., Vol. 3, p.1, 1974.
Possible Supernova Remnant:
Astr. Ap., 26, 105, 1973.
"Supernovae and SN Remnants", Ap. & Space Sc. Lib., Vol. 45, p.56, 1974.

33. 1973UGC...C...0000N
Re:UGC 07353
SAB(s)bc (de Vaucouleurs), Sb+ (Holmberg)

34. 1964RC1...C...0000d
Re:NGC 4258
= Holm 363a
Pair with NGC 4248 at 13.3 arcmin.
Photograph:
Ap. J., 97, 114, 1943.
Ap. J., 104, 218, 1946.
Ap. J., 138, 375, 1963.
Photometry:
Izv. Pulkovo 20, No.156, 87, 1955.
Soviet A.J., 32, 16, 1955.
Orientation, Rotation, Mass,
Ap. J., 97, 117, 1943.
Ap. J., 127, 487, 1958.
Ap. J., 138, 375, 1963.
Spectrum:
Ap. J., 135, 698, 1962.
HII Regions:
Zeit. fur Ap., 50, 168, 1960.
Radio Emission:
Phil. Mag., 43, 137, 1952.
Handbuch der Phys., Vol. 53, 253, 1959.
M.N.R.A.S., 122, 479, 1961.
P.A.S.P., 72, 368, 1960.

35. 1961Hubbl.B...0000S
Re:NGC 4258
Sb
PH-321-MH
Apr. 27/28, 1951
103aO
30 min
Enlarged 5.5X
NGC 4258 is probably a member of the Ursa Major Cloud.
The fact that the plane of this galaxy is inclined only 20 dgrees
to the line of sight partly explains why the dust lanes are
so prominent across the central lens of NGC 4258. These lanes
are quite chaotic. They do form a very rough spiral pattern
throughout the central region. There are two principal
luminous arms on the periphery of the bright central lens.
Numerous knots, presumably HII regions, are present
in these arms. Very faint spiral arms threading through
the outer envelope can be seen in the insert. The outer
arms are highly resolved into individual stars with the
200-inch. Normal novae have been found, but as yet no
Cepheid variables are known in NGC 4258. A reproduction of
NGC 4258 in negative form, given by Hubble in Ap. J., 97, 225,
1943, shows the intricate detail of the dust pattern in the
central region.


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