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Notes for object MESSIER 051a

35 note(s) found in NED.


1. 2011AJ....141...23B
Re:NGC 5194
A.18. NGC 5194
NGC 5194 is a grand-design spiral galaxy at a distance of
D = 8.0 Mpc which is undergoing interaction with NGC 5195.
We report 47 holes in NGC 5194 with only one type 3 hole
detected. Most of holes are in fact supershells, with one of those
(no. 5) being superposition of two or more holes.

2. 2009ApJ...697.1870E
Re:NGC 5194
NGC 5194 (M 51) We were able to measure 41 offsets between CO and H{alpha} at r
= 2.5-6 kpc (0.9'-2.2'), and found that their dependence on {OMEGA} is
different for the two spiral arms. The offsets of arm2, directly connected to
the companion galaxy NGC 5195, show negative dependence on {OMEGA}. We have
therefore derived {OMEGA}_P_ and t_SF_ by the {chi}^2^ fitting to the offsets of
arm1 only. The difference in the {OMEGA}-{theta} distribution for the two arms,
may be attributed to the tidal interaction with the companion. This is because
the interaction can cause asymmetry in the disk, and the outer part of the
spiral arm connected to the companion could be a material arm.
From the derived {OMEGA}_P_ and the RC, we calculate R_CR_ = 8.0^+0.8^_-1.0_
kpc, or 2.9^+0.2^_-0.4_ arcmin, and the ILR to be at r ~ 2-4 kpc, which is
slightly outside of the inner edge of spiral arms. The derived values of R_CR_
in Table 5 span a range more than a factor of 2, indicating the difficulty of
its determination. Zimmer et al. (2004) derived {OMEGA}_P_ to be about 40 km
s^-1^ kpc^-1^, from the TW method using the 45 m CO data (Nakai et al. 1994),
while Meidt et al. (2008) applied the radial TW method to other CO data (Shetty
et al. 2007) and derived two pattern speeds of about 90 and 50 km s^-1^ kpc^-1^
for r <~ 2 kpc and 2 <~ r <~ 4 kpc, respectively, with a possible
third pattern of {OMEGA}_P_ ~ 20 km s^-1^ kpc^-1^ for 4 <~ r <~ 5 kpc.
As the {OMEGA}_P_ values from Zimmer et al. (2004) and this work are both
between 50 and 20, derived by Meidt et al. (2008), these three works are in good
agreement. On the other hand, Knapen et al. (1992) calculated the arm/interarm
ratio of SFE along the two arms, and showed that positions of ILR, CR (at r ~ 2'
or 6 kpc), and outer Lindblad resonance (OLR) from Elmegreen et al. (1989) were
in good agreement with the minimum of this ratio. They also found that the
pattern of this ratio along the position in arms is quite similar for the two
arms, and claimed that some global triggering mechanisms for star formation
should be at work. This pattern they found is not consistent with our result
showing different offset distributions for the two arms, as well as the location
of the CR.
Bastian et al. (2005) estimated ages of H II regions in this galaxy as <~10
Myr based on population synthesis models, and the derived value of t_SF_ is
consistent to their ages. Recently published extinction-corrected distribution
of star-forming regions (Kennicutt et al. 2007) and the latest CO observations
with the 45 m and CARMA (Koda et al. 2009) of this galaxy will be able to
improve the current results in terms of reliability of location of H II regions,
the spatial resolution of CO map, and the quality of the RC.

3. 2009A&A...503..409H
Re:NGC 5194
NGC 5194(M51): In M51, the polarized emission is clearly detected throughout the
disk, though there are large variations in the polarized fraction. The bright
polarized emission traces out a spiral pattern that runs parallel to the optical
arms. The minimum in polarized intensity occurs at the PA of the receding major
axis (PA = 172^deg^, as tabulated in Table 1). The companion, NGC 5195, is not
detected in polarization. The polarization fraction at 22 cm in M51 is variable,
remaining lower than 5% within most of the optical disk, and increasing at large
radii, beyond the outer spiral arms, to as much as 25-30%. The orientation of
the magnetic field lines closely tracks both the large-scale spiral pattern (as
also seen by Horellou et al. 1992, see their Fig. 10), as well as small-scale
features that often have dust-lane counterparts in the optical imagery. In two
locations on the eastern side of the disk, the polarized emission crosses from
the inside of the optical arm to the outside; at the crossing point, the
magnetic field vectors turn from running parallel to the spiral to follow the
polarized emission across the arm. These features occur near
({alpha}J2000,{delta}J2000 = (13:30:1.5,47:12:15) and (13:30:5.4,47:10:30).
Systematic variation in the Faraday depth is seen as function of azimuth, which
will be discussed in Paper III. Two background double radio sources are detected
with very high signal-to-noise, including one with comparable integrated P from
each lobe. In Stokes I, the brightness ratio of the two lobes in that source is
actually 0.75, with the western lobe being the brighter. The best estimate of
the Galactic foreground RM for this field is +12 +/- 2 rad m^-2^.

4. 2007MNRAS.379.1249D
Re:NGC 5194
NGC 5194 is an almost face-on spiral galaxy in interaction with NGC 5195. Its
nucleus is classified as a Seyfert type 2 (Ho et al. 1997). Many studies have
been made on the structure and the nucleus of this nearby galaxy. A large
outflow bubble extends up to ~9 arcsec (~42 pc) north of the nucleus and a
bright cloud is located about 3 arcsec south of the nucleus. These structures
have been observed at different wavelengths (Ford et al. 1985), and they are
found to trace the biconical NLR along a PA of 163{degrees}. NGC 5194 is hosting
a radio jet, which interacts with the surrounding interstellar medium.
The SAURON stellar continuum map (Fig. 4f) shows the presence of dust lanes.
The stellar velocity field has a regular rotation pattern with its major-axis at
a PA ~ -165{degrees}, deviating by ~25{degrees} from the presumed LON
orientations (PA = 170{degree}; Tully 1974). The stellar velocity dispersion is
featureless.
The H{beta} emission-line flux is very high in the centre and for R > 5
arcsec it traces the spiral arms of the galaxy. The [O III] emission-line flux
traces the ionization cone of NGC 5194. The [O III] intensity map shows the
outflow bubble in the north and the bright cloud in the south of the nucleus
corresponding to the end of the radio jet. The emission line ration [O
III]/H{beta} peaks in the centre (with values up to 8) and in the southern cloud
(values between 3 and 5). The ionized gas velocity field seems to be dominated
by simple galactic rotation, but presents some distortions very probably due to
the outflow observed in the inner 10 arcsec. The ionized gas velocity dispersion
rises towards the centre.

5. 2007AJ....134..648M
Re:NGC 5194
NGC 5194 (M51; Figs. 7.57, 8.8, 9.57, 20.57): The nucleus is completely obscured
and surrounded by bright extended emission and crossed by dark dust lanes. The
inner several hundred parsecs show some few isolated star clusters, while the
outer regions are richly crowded with clusters and star-forming regions.

6. 2006MNRAS.366.1265B
Re:NGC 5194
Two emission lines are visible in the very centre of the galaxy and may account
for the "dip" in the rotation curve shown in the PV diagram. The strong H II
regions discriminate the great spiral structure from the rest of the galaxy. A
flow of H II regions is seen extending towards its companion. This galaxy has
been studied in H I by Rots et al. (1990), in both H I and H{alpha} (scanning
FP) by Tilanus & Allen 1991) and more recently in CO by Kuno & Nakai (1997). NGC
5195, the galaxy's companion, has been observed in H{alpha} through this study,
but it is impossible to get kinematical information as it is an early-type
galaxy (SB0p).

7. 2006A&A...460...45G
Re:NGC 5194
NGC 5194 (M 51a, UGC 8493, Arp 85a). A clearly unresolved nuclear source is
identified in the hard band of M51 coincident within 2.87 " with the near IR
nucleus (Fig. 5). Dudik et al. (2005) class it as an object that reveals a hard
nuclear point source embedded in soft diffuse emission. Its spectral properties
suggest that the source can be modeled by a combination of MEKAL at kT = 0.61
keV plus a power law with {GAMMA} = 2.67 and column density consistent with the
galactic value, and this fitting provides a fairly low luminosity in the hard
band (1.38 x 10^38^ erg s^-1^). Dewangan et al. (2005) obtain XMM-Newton
observations for the galaxy that show an extremely flat continuum and a narrow
iron K{alpha} line. They investigate different models for the galaxy, the best
one being more consistent with a reflection of the primary power law ( {GAMMA} =
1.9) by cold and dense material. By using this model, they estimate a luminosity
of 1.8 ~ 10^39^ erg s^-1^, which is a factor of 10 larger than our estimation.
Cappi et al. (2006) fit its XMM-Newton spectrum with a combined power law with
{GAMMA} = 0.6 and thermal with kT = 0.5 keV, together with an Fe K line with
EW(Fe K) = 0.986 keV, and get L(2-10 keV) = 3.3 x 10^39^ erg s^-1^, a factor of
20 brighter than our determination. These differences can be attributed either
to the different model used or maybe to the differing spatial resolution of
XMM-Newton and Chandra data. It has to be noticed that the iron line FeK has not
been included in our fitting, but it is clearly detected. We note that, whereas
UGC 08696 shows a compact nuclear source in this energy band, it cannot be
directly associated with an FeK line because it has a broad high-energy
component at these energies.

8. 2005ApJS..157...59L
Re:NGC 5194
NGC 5194 (M51) is a grand-design Sbc galaxy at a distance of 7.7 Mpc, which is
interacting with its companion NGC 5195. Six ULXs are associated with the
galaxy, with ULX6 on the outer edge of a spiral arm, and all the other five
right on the thin knotty spiral arms. ULX1 (IXO 79), ULX2, and ULX3 (IXO 80) are
near bright knots on the DSS image that are probably young star clusters. All
ULXs have exhibited variations by more than 50% during 6 years of observations.
ULX3 showed a luminosity drop from 4 * 10^39^ to below 0.7 * 10^39^ ergs s^-1^
in the observations. This source appears to have 2 hour periodic variations in a
recent Chandra observation (Liu et al. 2002b). ULX4 is IXO 78 in CP2002. ULX5
(IXO 81) showed variability during a 6 day observation.

9. 2005ApJ...622..217W
Re:NGC 5194
NGC 5194 and NGC 5195.
NGC 5195, the smaller part of M51, has an independent (SBF) distance;
there appears to be no separate determination for NGC 5194, at least
of moderate to high quality. I have assigned them the same distance.
Normally I strenuously avoid anything like this "companion" or
"member of the same group" argument for distance, but in this case
there appears to be no choice. Note that NGC 5194 is not used in any
peculiar velocity calculations, only in those of the luminosity
field.

10. 2004A&A...419..501F
Re:NGC 5194
NGC 5194 - We considered the central emission plateau of diameter
90". The motivation for this choice instead of selecting a smaller
region around the nucleus was that the plateau represents a transition
between disks and more active circumnuclear regions in terms of MIR
properties. Besides, the emission from the Seyfert nucleus is diluted
and completely negligible within this large aperture. We adopted the
average extinction, weighted by intrinsic H{alpha} luminosities, derived
by Scoville et al. (2001) from H{alpha}/Pa{alpha} decrements of a large
sample of HII regions, assuming it is representative of the effective
extinction throughout the central plateau. We applied a small correction
to this extinction to account for the different line emissivities and
extinction laws adopted. The [N II]/(H{alpha} + [N II]) ratio in the
central d ~ 20" is high and reaches{approx} 0.85 due to the Seyfert
nucleus but goes down to z~0.3 outside these regions (Rose & Searle
1982).

11. 2002ApJS..140..303L
Re:NGC 5194
NGC 5194 (Fig. 36).-The HUT spectrum does not include the LINER nucleus
of NGC 5194 but rather points at a region about 15" away. The spectrum
indicates one or more H II regions with emission from all of the
expected stellar-wind lines. The high metallicity may be responsible
for the somewhat unusual Si IV and C IV profiles with their narrow
emission peaks. We find an age of 5 Myr.

12. 2002ApJS..139....1T
Re:NGC 5194
NGC 5194 (S2).-Results of the first ASCA observation are presented in
Terashima et al. (1998b). The second ASCA observation performed in 1994
is discussed in Ptak et al. (1999) and Fukazawa et al. (2001). In this
paper, we concentrate on the first observation in 1993 because the SIS
data in 1994 suffered from serious telemetry saturation. The hard- band
image is extended and indicates that the AGN does not dominate the hard
X-ray flux. The detection of a strong fluorescent Fe K line gives strong
evidence for the presence of a heavily obscured AGN. Long-term
variability in the hard X-ray band also supports the presence of an AGN
(Table 15; see also Fukazawa et al. 2001). A recent Chandra spectrum
that spatially isolates the nucleus confirms the presence of a strong Fe
K fluorescent line (Terashima & Wilson 2001). The Compton-thick nature
of the nucleus is further suggested by the BeppoSAX detection of an
absorbed (N_H_ = 5.6^+4.0^_-1.6_ x 10^24^ cm^-2^) power-law continuum
above 10 keV (Fukazawa et al. 2001).

13. 2002AJ....124..675C
Re:UGC 08493
M51. Very large galaxy; the 1.4 GHz flux density is from Condon &
Broderick (1988).

14. 2002A&A...389...68G
Re:NGC 5194
NGC 5194 (M 51): our two methods are in good agreement, but
the values of the position angles in particular, using the
primary minima, are quite discordant with the values obtained
from the analysis of the velocity fields. Note that they are
also similar to some of the derived photometric values. The
deprojected galaxy using our values looks quite good, as
already noted in GGA (1991). There is, however, a secondary
minimum, which is in agreement with the values derived from
the velocity fields. With these values we get also a round
deprojected galaxy. We adopt the value from Rots et al. (1990),
which are as stated, in agreement with the average of the
secondary minima value.

15. 2001ApJS..137..139S
Re:NGC 5194
NGC 5194 (M51). - We adopt the PNLF distance from Feldmeier,
Ciardullo, & Jacoby (1997).

16. 2001ApJS..133...77H
Re:NGC 5194
NGC 5194, M51 (S2). - Ford et al. (1985) first drew attention to the
morphological details of the radio emission in the center of this galaxy.
In addition to the "extranuclear cloud" located ~4" to the southeast of
the nucleus, they noticed the ringlike appearance of the diffuse emission
to the northwest of the nucleus. Ford et al. postulated that these
features can plausibly be interpreted as bubbles created by a bipolar jet
or outflow emanating from the nucleus. A much deeper, subarcsecond 6 cm
map published by Crane & van der Hulst (1992) shows convincingly that the
southeastern lobe of emission is connected to the nucleus by a thin,
sinuous, jetlike feature, and the overall radio structure is embedded
within the extended optical emission-line region imaged by Cecil (1988).
Our maps qualitatively resemble the earlier versions. We wish only to draw
attention to a knot of emission which lies ~28" (1 kpc) to the northwest
of the nucleus, roughly along a straight line connecting the other
features. The source has S_20_ = 1.9 mJy and S_6_ = 1.4 mJy, and it is
unresolved. Since the density of background sources stronger than
S_20_ ~ 2 mJy is ~10^5^ sr^-1^ (Windhorst et al. 1985), the probability
that the source is unrelated to M51 is quite small (<1%). It is unclear,
however, whether the source is directly associated with the outflow itself,
in which case the total extent of the radio source would be 35" (1.3 kpc)
instead of 24" (0.9 kpc) as we have adopted in Table 5. Our flux densities
for the nucleus are consistent with the values of Hummel et al. (1987;
S_20_ = 3.6 mJy, {DELTA}{theta} = 1.3"), Crane & van der Hulst (1992;
S_6_ = 0.89 mJy, {DELTA}{theta} = 0.3"), and Turner & Ho (1994;
S_6_ = 1.1 mJy, {DELTA}{theta} = 1.1"). Thean et al. (2000) give
S_3.6_ = 0.5 mJy ({DELTA}{theta} = 0.3"). Crane & van der Hulst (1992)
remarked that their 6 cm data show marginally significant linearly
polarized emission coincident with the extranuclear cloud to the southeast.
Our maps confirm this finding, both at 6 and 20 cm (Fig. 16i); in addition,
a number of other peaks (S_pol,6_^P^ ~ S_pol,20_^P^ ~ 0.2 mJy beam^-1^) of
comparable statistical significance appear to be associated with ringlike
feature to the northwest of the nucleus.

17. 2000ApJ...534..670T
Re:NGC 5194
NGC 5194.-The M/L in the disk region is almost flat or rather decreases
outward. The peculiar behavior of the SMD, and therefore of the M/L, is
probably due to an RC disturbed by tidal interaction with the companion
galaxy NGC 5195. In the bulge region, the M/L is flat or slightly
decreases inward to r = 700 pc. Within r = 700 pc, it looks flat or
slightly increasing, while the spatial resolution is not sufficient to
reveal the details.

18. 1999ApJS..124..403S
Re:NGC 5194
5.16. NGC 5194
The grand-design spiral galaxy M51 has bisymmetric spiral arms of
molecular gas starting from about 15" (600 pc) from the galactic center.
In the central 1', the western arm has larger amount of molecular gas
than the eastern arm, and noncircular motions are evident on the both
arms, as has been known from previous observations (Lo et al. 1987;
Vogel, Kulkarni, & Scoville 1988; Rand & Kulkarni 1990; Adler et al.
1992; Tosaki 1994; and Aalto et al. 1999). Inside the arms, the
azimuthally averaged surface density of gas once declines and then
increases toward the center. The central rise is due to the gas clump
at about 1.2" (50 pc) northwest of the radio-continuum nucleus (the
cross in our map), which is a dwarf AGN (Crane & van der Hulst 1992).
The kinematics of the nuclear component is not symmetric with respect
to the systemic velocity of the galaxy. The range of velocities of the
nuclear component is 450-585 km s^-1^, while that of the galaxy is
367-560 km s^-1^ with the systemic velocity of 463 km s^-1^. The
nuclear gas component has been detected in CO by Scoville et al. (1998)
and Aalto et al. (1999). Our data confirm the spatial and kinematical
offset of the nuclear CO(2-1) peak reported by Scoville et al. (1998).
The CO peak near the nucleus is spatially and kinematically similar to
the nuclear peak of HCN detected by Kohno et al. (1996). The relatively
weaker emission in blueshifted velocities in CO than in HCN, noted in
CO(2-1) by Scoville et al. (1998), is also seen in our CO(1-0) data.
The CO(1-0) flux of the nuclear component is 15.8 Jy km s^-1^, which
corresponds to the mass of molecular gas of 1.5 x 10^7^ M_sun_.

19. 1998ApJS..114...59L
Re:NGC 5194
NGC 5194 (M51).--This is one of Heckman's (1980) original transition objects
with oxygen line ratios comparable to Seyfert galaxies. Among the most famous
LINER galaxies, M51 is one of only two in this sample to show Pa{beta} in
emission (although it is very weak). M51 also shows strong [Fe II] and H_2_
emission and has estimated ratios among the highest in this data set,
significantly above any Seyfert or starburst galaxy. A bubble of H{alpha}
emission is seen just off of the nucleus (Larkin et al. 1998). Known as the
Whirlpool Galaxy, it has an obvious interaction with NGC 5195, which may
contribute to any nuclear activity. No broad lines are detected by Filippenko &
Sargent (1985). The only obvious atomic absorption feature in M51 is the Na
doublet, although Mg may also be present.

20. 1998A&AS..128..153M
Re:GB1 1327+474
M51; NGC5194; UGC8493. Low-luminosity star-burst galaxy with faint
non-thermal radio core. References to WSRT and Effelsberg maps, as
(1988AJ.....87.1064C). The spectrum breaks at about 1.4GHz.
Unique radio source; a more detailed discussion in the Appendix

21. 1998A&A...335..807A
Re:NGC 5194
This almost face-on, Sbc galaxy (also known as the "Whirlpool Galaxy"
and M51) has been the subject of numerous observational studies at a
wide range of wavelengths (e.g., most recently, Hill et al. 1997;
Grillmair et al. 1997; Berkhuijsen et al. 1997; Sauvage et al. 1996). In
particular, its grand design spiral pattern has been the testing ground
for theories of spiral formation such as density wave propagation (e.g.
Knapen et al. 1992). Smith (1982) has mapped NGC 5194 in a 170 micron
filter using the Kuiper Airborne Observatory (KAO). This study, which
also included photometry at various other FIR wavelengths, showed that
70% of the energy radiated by the dust arises from the M51 disk whilst
the remainder originates from NGC 5195 (the small interacting companion
4' to the north). In our data, the satellite is situated at the bottom
right of the map and makes an obvious contribution to the recorded emis-
sion. Once again there is recognisable reciprocity between the IRAS and
ISO morphology (although, note that the 'smear' in the 100 micron image,
towards the top-left corner of the figure, is a result of detector
hysteresis in the IRAS detectors rather than any physical phenomenon).
Hippelein et al. (1996) have used ISO Guaranteed Time to map M51 at
wavelengths of 60, 100 and 175 microns. Their longest wavelength image
shows a strong resemblance to our 200 micron data.

22. 1997ApJS..112..391H
Re:NGC 5194
NGC 5194.--The broad base of the H{alpha}+[N II] blend in NGC 5194 (M51) is
predominantly due to the wide, asymmetric wings of the narrow lines. But
careful scrutiny reveals that the extremes of the [N II] lines may extend to an
FWZI of 6000 km s^-1^ at the faintest flux levels (Fig. 14d). Although we
cannot formally recover such a weak feature with our line-fitting technique, it
is possible that broad H{alpha} is present.

23. 1997ApJS..108..155G
Re:NGC 5194
NGC 5194 (M51) is a very famous LINER in a host Sbc galaxy. Our H{alpha}
image comprises only the central 2'. In this inner part, we have detected
210 weak H II regions. The nucleus is extended, and the isophotes are
elongated in the north-south direction at P.A. = 340^deg^. In the south,
at 3" from the nucleus, there is a knot that is brighter than the nucleus
(see expanded plot in Fig. 11d). In the north direction, there is a ring
structure about 10" (300 pc) from the nucleus. The knot and ring show
optical emission lines characteristic of LINERs (Ford et al. 1985). The
knot shows broad [N II] and H{alpha} lines; the kinematics of the
circumnuclear emission is a consequence of a nuclear outflow (Cecil
1988). The radio continuum emission is extended with several structures
and diffuse emission aligned along the north-south direction, and almost
coincident with the knot, nucleus, and ring structure (Ford et al. 1985).

24. 1996ApJ...458..120S
Re:NGC 5194
NGC 5194 (M51)
This nearly face-on Sbc galaxy at an inclination 20^deg^ and distance 9.6 Mpc
has been extensively studied in all wavelengths. Tully (1974) derived a
rotation curve from optical spectroscopic data for a wide area. Rots et al.
(1990) have extensively mapped this galaxy in H I and obtained an intensity-
averaged H I velocity field. However, they are not appropriate to derive an
inner (a few kiloparsec) rotation curve, because the H I emission is very weak
in the central region (Rots et al. 1990), so that the intensity-averaged
velocity is significantly weighted by rotation velocity at larger radius.
Unfortunately, no H I PV diagram has been obtained, as yet along the major
axis. A high-resolution CO PV diagram has been obtained by Garcia-Burillo,
Guelin, & Cernicharo (1993) and Nakai et al. (1994). Here we use the CO PV
diagram by Garcia-Burillo et al. (1993). The outer rotation curve can also
be obtained by the H I velocity field, which agrees with that obtained from
the CO data.
After correcting for the inclination of i = 20^deg^, we obtained a CO and an
H{alpha} rotation curve as shown in Figure 8a. The CO rotation velocity at
R<~5 kpc is significantly higher than that from the H{alpha} velocity. This
may be due to the fact that the density wave velocity jump in the arms of M51
is as high as ~50 km s^-1^, which would cause a systematic velocity difference
of CO-emitting regions (dark lanes) from star-forming regions (OB stellar arms)
(Nakai et al. 1995, in preparation). According to the definition of a rotation
curve, we simply adopt the highest velocities (terminal velocities) along the
major axis. Hence, most of the final rotation curve obtained in Figure 8b
coincides with the CO rotation curve. The rotation velocity increases steeply
near the nucleus, within 0.5 kpc, reaching a maximum of 260 km s^-1^. Then it
remains flat up to 9 kpc, beyond which the rotation velocity declines to
130 km s^-1^ at R ~15 kpc. This declining rotation is similar to that observed
in NGC 1808.

25. 1994CAG1..B...0000S
Re:NGC 5194
[With] NGC 5195 [=] MESSIER 051
Hubble Atlas, pp. 26, 31
Sbc(s)I-II
PH-201-MH
May 14/15, 1950
103aO
20 min
NGC 5194 (M51) is similar to NGC 1566
on the preceding panel. The surface brightness of
the two principal grand design arms is high, seen
best in the print on the right. This lighter print
shows the intricate but well-organized dust lanes
inside the two major inner arms. Dust is also
present in the inter-arm region, well silhouetted
against the background disk light at the rim of
the bright central bulge where the short dust
lanes emerge almost radially from the bulge
before breaking into the general spiral pattern.
The heavy print on the left shows the smooth
luminosity that envelops the companion whose
classification is outside the classification system,
although it has variously been classified as SB0
pec and Amorphous. The dust lanes from one of
the branched arms of M51 are silhouetted
against the companion, which obviously is behind
the arm that sweeps across its image.
The strength of the spiral pattern is well
shown in the composite photographs given by
Zwicky (1955), where the dust pattern is also
particularly well seen. The prevalent dust lanes
in the central bulge close to the nucleus are
shown in a greatly enlarged image of the center
on page 31 of the Hubble Atlas.
The distance to M51 is considerably smaller
than the distance to the Virgo Cluster, as judged
by the ease of resolution into brightest stars and
HII regions. The redshift of M51 is v_o = 541 km/s.
This value is consistent with the distance
modulus of m - M = 30, estimated from the ease
of resolution into stars.
This agreement shows that any random
(non-cosmological) velocity is near zero within
the distance of 10 Mpc from the Local Group.
This conclusion follows because the velocity-distance
ratio (i.e., the local value of the Hubble
constant) for M51 itself is 54 km/s Mpc^-1^ using
the M51 distance modulus of m - M = 30 (D = 10
Mpc), and noting that this local ratio is the same
as the global value of the Hubble constant
(Sandage and Tammann 1990).

26. 1994CAG1..B...0000S
Re:NGC 5194
[With] NGC 5195 [=] M 51
Hubble Atlas, pp. 26, 31
Sbc(s)I-II
PH-3922-S
March 30/31, 1962
103aE + H{alpha} interference
120 min
The H{alpha} interference filter image of
NGC 5194/5195 on the facing page illustrates why the
spiral pattern of this galaxy is of the grand
design, despite the superficial appearance of
multiple arms in the deep prints on panel 172. The
numerous HII regions outline the two principal
arms, which can each be traced for nearly a
whole revolution.
The most unusual feature of the pattern
concerns the arm that begins near but not on the
rim of the inner disk on the right-hand side of the
image here (the opposite side of the major axis
from NGC 5195). This principal arm is detached
from the rim, in contrast to its opposite mate,
which can be traced continuously inward until it
meets the rim.
The largest HII regions have cores that
resolve at the 10" level. This is consistent with
the calibration of HII linear core sizes in
luminosity class I-II late-type spirals (Sandage
and Tammann 1974a), putting M51 at a distance
of 10 Mpc, as described earlier (panel 172).

27. 1993ApJS...86....5K
Re:NGC 5194
NGC 5194 (M51); Sbc, LINER.
The Whirlpool Nebula forms an interacting system with its companion
NCG 5195 (Keel et al. 1985). Heckman(1980) and Baldwin et al.(1981) have
classified NGC 5194 as a transition galaxy between a LINER and a Seyfert
galaxy because of the presence of broad wings in its optical emission
lines. Studies of the radio emission of NGC 5194 show a complex structure
of extranuclear bubbles, probably ejected from the nucleus (Ford et al.
1985). However, the composite nuclear activity in the radio does not have
a counterpart in the X-ray (Palumbo et al. 1985). The X-ray emission is
not concentrated in the nucleus but is extended over the galaxy disk. The
X-ray emission is explained by Palumbo et al. (1985) as being due to
evolved stellar systems such as X-ray binaries and old starbursts, or to
gas outflowing from the nucleus. The UV spectrum does not show evidence
of nonthermal activity; except for Si III and C III], there are no other
detected emission lines. The presence of a strong absorption feature of
Al III {lambda}1857 and the shape of the continuum suggest that the
dominant population is A- G stars (Ellis et al. 1982).

28. 1989AJ.....98..419V
Re:B3 1327+474C
M51. The 408 MHz flux is inclusive of B3 1327+427A and B.

29. 1976RC2...C...0000d
Re:NGC 5194
= M51a
= Arp 85a
= VV 1a
= Holm 526a
= Kara[72] 379a
Interacting pair with NGC 5195 at 4.8 arcmin, connected with outer streamers.
Diameter of nucleus:
Ap. J. (Letters), 155, L129, 1969.

30. 1973UGC...C...0000N
Re:UGC 08493
VV 1, Arp 85
SA(s)bc pec (de Vaucouleurs), Sc- (Holmberg)
Paired with UGC 08494 at 4.6, 16
Total diameter for UGC 08493 + UGC 08484 approximately 15. x 7.5
In Arp's class "galaxies with large, high surface brightness companions
on arms"; "faint plumes and extensions from companion" (Arp)

31. 1964RC1...C...0000d
Re:NGC 5194
= Holm 526a
Part of M51
Well-known interacting pair with NGC 5195 at 4.8 arcmin separation.
In the M101 Group.
B magnitude (source F) is NGC 5194+95.
Photograph:
Ap. J., 32, 34, 1910.
Ritchey, L'Evolution de Astrophographie..., S.A.F., Paris 1929.
Handbuch der Ap., 5, 2, 843, 1933.
Medd. Lund, I, 170, 1950.
P.A.S.P., 67, 232, 1955.
P.A.S.P., 75, 222, 1963.
Photometry:
Ap. J., 46, 206, 1917.
Ap. J., 50, 385, 1919.
Ap. J., 83, 424, 1936.
Ap. J., 91, 528, 1940.
Ap. J., 108, 415, 1948.
Sov. A.J., 32, 16, 1955.
Izv. Pulkovo, 20, No.156, 87, 1956.
Publ.Byurakan, XXV, 15, 1958.
Medd. Lund, I, 170, 1950.
Medd. Lund, II, 128, 1950.
Spectrum:
Ap. J., 116, 66, 1952.
Ap. J., 135, 734, 1962.
HII Regions:
Observatory, 79, 54, 1959.
Zeit. fur Ap., 50, 168, 1960.
Radio Emission:
M.N.R.A.S., 122, 479, 1961.
Ap. J., 133, 322, 1961.
Handbuch der Phys. 53, 253, 1959.
HI Emission:
Ap. J., 126, 471, 1957.
P.A.S.P., 72, 368, 1960.
B.A.N., 15, 506, 314, 1961.
SN 1945 (in NGC 5195)
P.A.S.P., 57, 174, 1945.

32. 1961Hubbl.B...0000S
Re:NGC 5194
Part of M51
Sc
PH-201-MH
May 14/15, 1950
103aO
20 min
Enlarged 4.8X
NGC 5194 is one of the most magnificent spirals in the sky.
The entire spiral pattern is dominated by the dust lanes.
The two most opaque dust lanes lie on the inside of the
two brightest spiral arms. These two principal arms plus
their associated dust lanes wind into the central region
along an almost perfect spiral path. The dust arms are
very highly branched. Thin filaments break away from
the main dust path and cross the luminous arms almost
at right angles. Multiple secondary dust lanes exist
throughout the central lens. lndividual dust lanes of the
secondary pattern cannot be traced, but, rather, separate
segments exist which, when viewed with other segments,
form a rough spiral structure. The two main arms can be
traced for one and a half revolutions. Branching occurs
from one luminous arm to the other after about three-quarters
of a revolution. Each branch continues as a separate
arm, giving the spiral the appearance of having a
multiple-arm structure. Actually the multiplicity is not
like that of NGC 2841 or NGC 0488 because, in these, two main arms
cannot be traced but the multiple filaments begin
immediately at the periphery of the amorphous central lens.
The companion galaxy NGC 5195 is an Irr of the M82
type. The dust from the northeast arm of NGC 5194 crosses in
front of NGC 5195 on the eastern edge, but there are dust
patches internal to NGC 5195 itself on the west side. NGC 5195
closely resembles NGC 3077 (pg. 41) and M82. Holmberg
has found the international color index of the companion
to be 0.98. This is redder than his measures of M82 (CI
= 0.81) and NGC 3077 (CI = 0.68), but part of the redness may
be due to internal absorption. NGC 5194 is close enough
to us to be easily resolved into stars along the spiral arms.
Many HII regions are present. No clusters, either globular
or open, have been identified with certainty. The
distance modulus of these two galaxies must be about
(m-M) = 27.5, which is slightly more distant than the
M81 Group.
Negative photographs of NGC 5194/5195 showing the
dust lanes in both galaxies to good advantage have been
published by Zwicky (Publ. A. S. P., 67, 232, 1955).
Also the characteristics of the two principal luminous
arms are well revealed by a superposition trick of negatives
taken in different colors. Plate IV of Zwicky's paper
shows the intricate dust lanes quite well.
The details of the dust lanes in the center of NGC 5194 are
of interest. The nuclear regions are shown on page 31 of
this Atlas.

33. 1961Hubbl.B...0000S
Re:NGC 5194
Messier 051
Sc
A-96
May 15/16, 1926
180 min
Enlarged 16.0X
The opaque dust lanes do not spiral into the nucleus as
in M100 or M101 but start tangent to a circular luminous
region centered on the nucleus. The central region is not
amorphous but is crossed by thin dust lanes in a haphazard
fashion. The two principal opaque lanes seen here
silhouetted against the edge of the bright center continue
to spiral outward. They eventually end up on the inside
of the two brightest spiral arms. See page 36.

34. 1959VV....C...0000V
Re:VV 001a
= NGC 5194
F8
V = +546 km/sec;
V = +560 km/sec from NI + H(alpha), lambda 3727
(Page, T., Ap. J., 116, 63, 1952)
Yerkes Type: fS1

35. 1918PLicO..13....9C
Re:NGC 5194
NGC 5194 and NGC 5195
Vol VIII, Plate 47. The beautiful spiral M.51 in Canes Venatici. Including very
faint matter to the north of 5194, scareely visible in any of the very numerous
published reproductions, it covers an area about 12' x 6' in p.a. approximately
30^deg^. A sharp stellar nucleus in 5194, and the whorls show a multitude of
stellar condensations. The satellite nebula, 5195, has a bright, elongated
nucleus; its nebulosity is of a more diffuse type, without discernible spiral
structure, and with several rifts which suggest absorption effects. See Abs.
Eff. 22 s.n.


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