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Notes for object NGC 4449

22 note(s) found in NED.


1. 2011AJ....141...23B
Re:NGC 4449
A.15. NGC 4449
Another dwarf irregular galaxy, NGC 4449, is located at a
distance of D = 4.2 Mpc. It has a very extended HI structure
reaching out to six times the Holmberg radius. The R_max_ radius
for this galaxy was taken at the edge of the HI disk thus
excluding this structure. What is also unusual about NGC 4449 is
that it has two counterrotating gas systems (Hunter et al. 1998).
We detected 20 HI holes in NGC 4449, most of them located
within R_25_ and six located in the extended structure outside the
R_max_ radius.

2. 2008MNRAS.390..466E
Re:UGC 07592
UGC 7592. This galaxy does not show any evidence for rotation. However, a
velocity amplitude of about 25 km s^-1^ is observed on its velocity field.

3. 2006A&A...452..739S
Re:NGC 4449
X4 in NGC 4449.
The very blue Magellanic irregular galaxy NGC 4449 contains a lot of HII
regions. In this case, the ULX radio counterpart candidate is a strictly compact
radio source projected against the galactic disk (electronic Fig. 5).
In the FIRST image, it outshines the galactic nucleus. Thus, the possibility
that we are again dealing with a background object cannot be ruled out.
Alternatively, the ULX source could be associated with some of the apparent
extended regions seen at optical wavelengths within the X-ray error box. In
fact, this ULX source corresponds to source 15 in the Chandra results reported
by Summers et al. (2003), who assumed it to be a supernova remnant (SNR) based
on the old VLA observations of Bignell & Seaquist (1983) with angular resolution
poorer than FIRST.

4. 2004MNRAS.349..225G
Re:UGC 07592
4.15 UGC 7592 This magellanic galaxy has an odd looking shape. It has a
strong H{alpha} emission with large H II regions bathing in a diffuse
gas. The chaotic H{alpha} velocity field could be drawn over the whole
optical disc. Although there is no clear rotation pattern, we can see a
regular increase of the radial velocities (from 170 to 220 km s^-1^)
along the main body, from south-west to north-east. This is in good
agreement with the velocity field found by Valdez-Gutierrez et
al. (2002). Both velocity fields have been obtained with a scanning
Fabry-Perot and are quite comparable, but our velocity field goes
deeper in the detection of the faint diffuse emission, so that our
velocity field is more extended in the outer parts. Nevertheless, there
is a systematic shift of 20 km s^-1^ in our velocity field because the
calibration line is neon instead of H{alpha} and no correction has been
applied (see Paper I for a discussion of this problem). A comparison of
the H{alpha} and H I velocity fields (such as WHISP or Hunter et al. 1999,
from VLA observations) confirms that the gas in the main optical body is
rotating in the opposite sense from gas at larger radii. The
high-resolution map provided by Hunter et al. (1999) shows that the
neutral gas is mainly found in a ring surrounding the optical disc, with
streamers around. This unusual shape, together with the odd velocity
field, led previous studies cited above to conclude that this galaxy has
been disturbed by an external perturbation. Hunter et al. suggest that
UGC 7592 has been affected by possible gas capture (a counter-rotation
motion can result in the infall of gas with a different angular momentum
from that of the host), by merger or by external perturbations. [See the
model of the interaction between UGC 7592 and its neighbour DDO 125 at
17 kpc made by Theis & Kohle (2001) which reproduces the features of the
H I disc assuming that, prior to the encounter, the H I gas formed an
extended, almost homogeneous disc with a large scale of about 30 kpc and
a radial extension of 40 kpc.] Perhaps also, the origins of the opposite
motions and the streamers of neutral gas are different, suggesting an
external perturbation for the streamers and accretion for the
counter-rotation. One of the consequences is that it is impossible to
draw any significant rotation curve. This is why we give no kinematical
parameters in Table 2 for UGC 7592 and we present in Fig. 16 the radial
position-velocity diagram. Nevertheless, we checked the consistency of
our data with those of Valdez-Gutierrez et al. (2002), by tracing the
rotation curve with their kinematical parameters applied on our GHASP
data. The agreement is good but we go further out because of the larger
extension of our velocity field, and find a strong decrease of the curve
on the redshifted side beyond 100 arcsec, together with a strong
increase on the blueshifted side. Both effects are likely to be
explained by the counter-rotation of the main optical body with respect
to the gas at larger radii. In this respect, we notice that the outer
parts of our velocity field are in good agreement with the H I velocity
field obtained at VLA by Hunter et al. (1999).

5. 2003A&A...398..467K
Re:NGC 4449
NGC 4449. This boxy-shaped Magellanic irregular galaxy of high surface
brightness is a second ranked member of the CVn I cloud according to
its luminosity. NGC 4449 is enveloped in a huge H I "fur coat", whose
angular size (75') exceeds the Moon's diameter (Bajaja et al. 1994).
Based on photometry of the brightest stars, Karachentsev & Drozdovsky
(1998) estimated its distance to be 2.9 +- 0.6 Mpc. The WFPC2
photometry reveals about 27 000 stars seen in both images. The CM
diagram in Fig. 2 shows stellar populations of different kinds
including RGB stars. From the TRGB magnitude, 24.11 +- 0.26 mag, we
derive a distance of 4.21 +- 0.50 Mpc.

6. 2002ApJS..140..303L
Re:NGC 4449
NGC 4449 (Fig. 45).-The HUT pointing is not on the nominal center of
NGC 4449 but is offset by 1.5'. Consequently, the most active
star-forming regions are not in the aperture. This can be seen clearly
in the relatively "evolved" spectrum. O stars are present (from O VI
and broad C IV), yet this is not an H II-type spectrum, but the B star
contribution is dominant. Consequently, the characteristic age becomes
several tens of Myr.

7. 2002AJ....124..675C
Re:UGC 07592
Not a cataloged IRAS source; the 60 micron flux density was estimated
from the IRAS image.

8. 2002A&A...390...47S
Re:NGC 4449
NGC 4449: The Magellanic irregular galaxy NGC 4449 offers an
important opportunity to study the processes by which star
formation is sustained and propagated in irregular galaxies.
The first studies of HII regions in NGC 4449 have been done
by Crillon & Monnet (1969) and by Hodge (1969). Later more
detailed investigations have been made by several authors
(Hodge & Kennicutt 1983; Hill et al. 1998). In Fig. 15 our
slit position on the NGC 4449 is shown. The slit covers five
star forming regions in the galaxy. These star forming regions
are marked by the letters (A, B, C, D and E). Cross
identifications with previous determinations are presented in
Table 2.

9. 2001ApJS..137..139S
Re:NGC 4449
NGC 4449. - We adopt the bright star distance from
Karachentsev & Drozdovsky (1998).

10. 2000ApJ...542..186N
Re:NGC 4449
NGC 4449.-FIRST lists a 20 cm peak flux density of 1.7 mJy beam^-1^ at
5" resolution, with extended emission in P.A. 65^deg^, more or less
along the host galaxy major axis. We did not detect this object at 2 cm.

11. 1999ApJ...519...89C
Re:NGC 4449
NGC 4449.-This is a Magellanic Irr galaxy with many H II regions
and is undergoing active star formation (Bothun 1986). We found multiple
compact X-ray sources in this galaxy, none of which is coincident with
the galaxy center. The nearest X-ray source to the nucleus is located
39.3" (572 pc) from the nucleus.

12. 1999A&AS..136...35S
Re:NGC 4449
NGC 4449 -- Martin & Kennicutt (1997) indicate the presence of broad
He II {lambda}4686 and C IV {lambda}5808 in several regions of this
object.

13. 1998ApJ...506..222M
Re:NGC 4449
Excluding M82, NGC 4449 has a higher B-band luminosity than any
member of the sample, and its H I mass is actually twice that of M82.
While it is awkward to call it a dwarf galaxy, I include it here because
it provides a particularly dramatic example of the disturbances caused
by a burst of star formation in a young disk galaxy. The galaxy shown in
Figure 2h has a diameter of 5.6' (5.86 kpc) at the 25 B-mag arcsecond-2
isophote, which is a mere speck in the H I disk, which is ~13 times
larger (Bajaja, Huchtmeier, & Klein 1994). Much of the ongoing star
formation is taking place in a central barlike region running southwest
to northeast, although the recent increase in the star formation rate
north of the bar (see, e.g., Hill et al. 1994) gives the H{alpha}
emission a T shape. The entire galaxy is forming stars at the modest
rate of about 0.07 M_sun_ yr^-1^, but the star formation rate in complex
G alone is comparable to that in all of I Zw 18 or NGC 3738.
Although many filaments and partial shells appear in the H{alpha}
image in Figure 2, the locations of the larger kinematic complexes are
not immediately obvious. Echellegrams 1 and 2 were aligned parallel to
the bar and offset to its northwest side. The Doppler ellipses found on
the southern halves of these slits are associated with shell A, and the
peaks in the line profile are separated by as much as 160 km s^-1^. The
spatial extent of the line splitting increases from about 30" at a
projected "height" above the bar of 10" (170 pc) to approximately 45" at
a height of 24" (420 pc). The double-peaked line profile is particularly
prominent where these slits intersect a bright filament previously
noticed by Hunter & Gallagher (1990). The spatial axis of NGC 4449-3
follows this filament and shows a Doppler ellipse extending from the bar
to a projected height of ~40". The projected expansion velocity, 35 km
s^-1^, is consistent with the velocity difference measured by Hunter &
Gallagher (1990). The intensity of the blueshifted component is
stronger, which suggests a polar axis tipped away from our line of
sight. The geometry may be more complicated than a simple polar outflow,
however, as NGC 4449-3 also shows multiple high-velocity wisps across
the bar. The wisps extend up to +175 km s^-1^ from the
intensity-weighted average velocity. Their envelope has an elliptical
shape (labeled feature B), but the wisps do not form a clean Doppler
ellipse. Their origin is unclear, so they have not been associated with
an expanding complex in Figure 2l or Table 3.
Southeast of the bar along echellegram NGC 4449-7, Doppler ellipse I
is visible across the H{alpha} cavity. The measured expansion velocity,
50 km s^-1^, is consistent with the magnitude of the line splitting
Hunter & Gallagher measured across their filament 2. Farther south,
ellipse H extends to 43.9" between two bright filaments. The kinematic
signatures of complex I and H are clearly those of expanding shells, and
shelllike features are seen in the image. The H I column is also very
low within complex I (Hunter & Gallagher 1997). To the north of these
bubbles, patchy line splitting and wisps are detected up to Doppler
ellipse J. It is not clear whether this ellipse is related to complex I
or even complex C.

14. 1998ApJ...506..222M
Re:NGC 4449
The kinematic activity is not limited to the region near the bar.
Echellegrams NGC 4449-9 and NGC 4449-11 show Doppler ellipses at the
northwest end of the T, hereafter complex D. A larger region of line
splitting labeled "C" in Figure 2 shows several adjacent Doppler
ellipses over D ~ 25'' region. At the top of the T, complex G extends
from two H II complexes in the west to a faint arc on its eastern
boundary. Along NGC 4449-9, Doppler ellipse G is prominent in the [N II]
{lambda}6458 line, but the H{alpha} emission is difficult to separate
from the bright H II region emission. Along the eastern perimeter of the
galaxy, the three Doppler ellipses identified along NGC 4449-10 coincide
with partial rings of emission in the H{alpha} image.
All the Doppler ellipses identified on the echellegrams are plotted
on the H{alpha} image in Figure 2. The associated kinematic complexes
are outlined by dotted lines and several deserve further comment since
their boundaries are appreciably less well defined than the other
cataloged structures. Features B and J show very disturbed gas motion
but not clean Doppler ellipses, so they were not cataloged as expanding
shells. Only the faint, fairly diffuse, emission from complex G and
complex D shows the kinematic signature of expansion, so the brighter
regions were masked out of the apertures for shell photometry. The
spatial extent of complexes A, C, and H were estimated conservatively.
Complex A, restricted to the filaments comprising the Doppler ellipses,
corresponds very closely to a hole in the H I emission discovered by
Hunter & Gallagher (1997). Arc-shaped filaments extend farther, about
1.2 kpc, to the northwest but appear relatively quiescent (Hunter &
Gallagher 1997). As suggested by Hunter & Gallagher, these are probably
the inner ionized edges of H I cavities. The X-ray emission in both the
soft (0.12-0.28 keV) and hard (0.76-2.02 keV) ROSAT bands does extended
in the direction of bubble A well beyond the conservative radius of the
Doppler ellipse, 34.5"(600 pc) (Della Ceca, Griffiths, & Heckman 1997).
Several bubbles may be merging into a superbubble in the region of
complex C. The X-ray map of Della Ceca et al. (1997) also shows two
local maxima within complex C. The expansion associated with Doppler
ellipse H probably extends further to the northwest to include the loop
of emission identified by Hunter & Gallagher (1990; i.e., loop 1). Their
Figure 2b shows hints of a Doppler ellipse in the faint component of the
line. A prominent finger of very soft X-ray emission appears to curve
south from this complex (Della-Ceca et al. 1997). Overall the picture is
one of large shells breaking out of the barlike region, and many smaller
shells growing along the periphery of the disk.

15. 1998ApJ...506..222M
Re:NGC 4449
The H I surrounding NGC 4449 extends about 14 times farther than
the optical galaxy. The gravitational interaction with DDO 125 is
probably responsible for some distortion in the velocity field (Bajaja,
Huchtmeier, & Klein 1994), but the disk seems to be in regular rotation
about the center of NGC 4449 (Wilcots et al. 1996a). The velocity
increases from north to south across the extended disk-a gradient
opposite to that observed across the inner few arcminutes (see, e.g.,
echellegrams NGC 4449-1, -2, -7, and -10). The rotation curve in Figure
9 is based on the position-velocity diagram that Bajaja et al. extracted
along the H I ridgeline. The velocity rises to 65 km s^-1^ 15.7 kpc from
the galactic center. For an inclination of 51^deg^, the maximum circular
velocity is then 84 km s^-1^, which is near the middle of the range of
shell expansion speeds (30 -150 km s^-1^). For comparison, the circular
velocity of a halo with core radius r_0_ = 6.3 kpc is shown in Figure 9.
If a spherically symmetric halo of this type is a good description of
the gravitational potential in NGC 4449, then the gas swept into the
expanding shells is bound to NGC 4449.

16. 1994CAG1..B...0000S
Re:NGC 4449
CVn I Cloud
B4 Group
Hubble Atlas, p. 40
SmIV
H-523-B
June 26/27, 1935
Imp. Ecl.
20 min
NGC 4449 is a member of the very nearby
B4 Group (Kraan-Korteweg and Tammann
1979; hereafter KKT), also called the CVn I
Cloud by de Vaucouleurs (1975). The group,
described earlier on panel 324 with NGC 4395,
has of about 250 km/s. It includes
NGC 4144, NGC 4190 (at the right on this panel),
NGC 4214, NGC 4244, IC 4182, and a number
of Im dwarfs listed in KKT.
The surface brightness of NGC 4449 is
abnormally high. The face of the galaxy is covered
with bright HII regions and undoubtedly very
bright stars which have not yet (1991) been
distinguished from the HII-region candidates.
Brightest individual stars resolve out of the
background at a magnitude at least as bright as
B = 19.
The face of the galaxy is covered with H{alpha}
streamers and filaments. Its morphology is mildly
similar to that of the Amorphous types, such as
NGC 625 (panel 336), NGC 1569 (panel 336),
and NGC 3034 (M82; panels 333, 334), sometimes
called starburst galaxies.
The redshift is v_o = 250 km/s.

17. 1993ApJS...86....5K
Re:NGC 4449
NGC 4449; IBm, H II.
NGC 4449 is a very blue Magellanic irregular galaxy, containing a large
amount of gas, having a complex distribution of H II regions, and
undergoing active star formation (Hunter 1982; Bothun 1986). Many of the
UV observations of NGC 4449 are concerned with the off-nuclear H II
regions (see, e.g., Rosa et al. 1984; Lamb et al. 1986) and with a
peculiar supernova remnant (Blair et al. 1984b). Because of this, we have
been especially careful to extract only the one short- wavelength and the
one long-wavelength IUE spectra that were taken with the aperture placed
on the galaxy center.
The time evolution of the star formation rate in NGC 4449 is thought to
be constant, based on an analysis of the mass, blue luminosity, and the
strength of H{alpha} emission (Gallagher et al. 1984) and also based on
the strength of the infrared emission (Thronson et al. 1987). From
kinematical considerations, Hartmann et al. (1986) conclude that the
strong star formation rate is due to a merger or interaction with the
dwarf companion DDO 125. The poor match between the short- and the long-
wavelength spectra is probably due to the placement of the aperture.

18. 1976RC2...C...0000d
Re:NGC 4449
Photograph:
Ap. J., 152, 1067, 1968.
Ap. J., 194, 559, 1974.
A.J., 74, 515, 1969.
Astr. Ap., 1, 449, 1969.
Cont. Asiago, No. 203, 1968.
Photometry: P.A.S.P., 77, 130, 1965.
Ap. J., 152, 1067, 1968.
Vest. Kiev. Obs., 13, 104, 1971.
Vest. Kiev. Obs., 14, 103, 1972.
Spectrum:
A.J., 74, 515, 1969.
Astr. Ap., 1, 449, 1969.
Spectrophotometry:
Ap. J., 159, 809, 1970.
Sov. A.J., 13, 593, 1970.
Far UV:
N.A.S.A., SP310, p.559, 1972.
Dynamics:
Cont. Asiago, No. 191, 1967 = S.A.Ital., Atti X Conv. Catania, 1966.
HII Regions:
"Atlas and Catalogue", Univ. Washington, Seattle, 1966.
Ap. J., 156, 847, 1969.
Ap. J., 194, 559, 1974.
Astr. Ap., 1, 449, 1969.
Distance Modulus:
Ap. J., 194, 559, 1974.
HI 21cm:
Ap. J., 150, 8, 1967.
Radio Observations:
A.&.A., 31, 447, 1974.

19. 1973UGC...C...0000N
Re:UGC 07592
IBm (de Vaucouleurs), Ir I (Holmberg)
Box-shaped chaotic center region, diffuse outskirts

20. 1964RC1...C...0000d
Re:NGC 4449
Bright central core or bar with a nucleus or star. Partially resolved.
Irregular dark lanes. Several very irregular, well-resolved branches.
Photograph:
Ap. J., 64, 325, 1926.
Ap. J., 135, 697, 1962.
Handbuch der Phys., 5, 2, 843, 1933.
Spectrum:
P.A.S.P., 69, 297, 1957.
Ap. J., 135, 696, 1962.
Polarization:
Bull. Abastumani, No.18, 15, 1955.
HII Regions:
Zeit. fur Ap., 50, 168, 1960.
Radio Emission:
M.N.R.A.S., 123, 279, 1961.
HI Emission:
Epstein, Harvard Thesis, 1962.

21. 1961Hubbl.B...0000S
Re:NGC 4449
Irr I
H-520-H
Jan. 21/22, 1925
E40
105 min
Enlarged 4.0X
There are many HII regions in this galaxy, concentrated
mostly in the northern part where many knots appear in
this illustration. Dust patches are scattered through the
central regions. One is particularly well shown on the
eastern boundary of the galaxy.

22. 1918PLicO..13....9C
Re:NGC 4449
A very bright and interesting object, filling a space about 3.5' x 2'. It is of
exceedingly irregular structure, with many almost stellar condensations,
and a bright, nearly stellar nucleus. Of spiral type as to nebulosity, but
with very little evidence of spiral form.


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