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Notes for object NGC 4559

15 note(s) found in NED.


1. 2009A&A...503..409H
Re:NGC 4559
In this spiral galaxy, diffuse continuum emission is detected, but the polarized
component is extremely faint and only detected in a small region in the
southeast portion of the disk. This asymmetry is again consistent with the
lowest polarized intensity to be seen on the receding major axis. Deeper
observations would be needed to better characterize the polarized emission. The
equal double in the southern part of the field provides a consistent estimate of
the Galactic foreground RM of -5 +/- 2 rad m^-2^, while the remaining four
unresolved sources in the north and east of the field are all tightly clustered
around an RM of +6 +/- 2 rad m^-2^. This systematic difference of the RM by of
~10 rad m^-2^ over ~15' in a field so near the Galactic pole (b = 86^deg^) is
surprising.

2. 2008MNRAS.385..553D
Re:NGC 4559
NGC 4559: The H{alpha} velocity field of this late-type galaxy shows the
presence of streaming motions in its centre and is somewhat patchy far
from the centre. The H I disc, extending further out than the optical
disc, is warped and lopsided in both distribution and kinematics
(Barbieri et al. 2005). Their H I PV diagram revealed the presence of a
thick H I layer rotating 25-50 km s^-1^ more slowly than the value for
the thin disc.

3. 2007ApJS..173..538T
Re:NGC 4559
NGC 4559 (Fig. 16.23).-GALEX observations of this SA(r)0+; H II LINER galaxy
show diffuse off-plane FUV emission perhaps associated with extraplanar H I of
Barbieri et al. (2005). Discrete XUV-disk complexes are arranged in spiral arms
tightly wrapping the on galaxy periphery in a manner similar to NGC 4414. SDSS
imaging at blue wavelengths detects some of the UV-bright clumps. NGC 4559 is a
Coma I group member.

4. 2006A&A...452..739S
Re:NGC 4559
X4 in NGC 4559.
The Sc spiral galaxy NGC 4559 exhibits some easily resolved HII regions. X4
coincides with a compact and faint radio counterpart candidate in the FIRST
image as illustrated in electronic Fig. 6. It is clearly located within one of
the spiral arms. At optical wavelengths there is a possible HII region near the
ULX position that could be associated to. However, no extended radio emission is
detected around it.

5. 2005ApJS..157...59L
Re:NGC 4559
This Scd spiral galaxy, at a distance of 5.8 Mpc, hosts two ULXs, NGC 4559-ULX1
and ULX2. ULX1 (IXO 66) is 10" east of the optical nucleus, while
ULX2 (IXO 65) is coincident with some blue fuzzy objects on the extension
of a spiral arm.

6. 2004MNRAS.349.1193R
Re:NGC 4559
4.2.4 CXOU J123551.7+275604 (NGC 4559 X-1) This is the most luminous ULX
in the sample, with its observed luminosity at, or above, 10^40^ erg
s^-1^. Its X-ray spectrum was observed to soften between the
observations, with the X-ray emission in the second, more X-ray luminous
epoch represented by a significantly softer power-law photon index than
the first (~2.16 against ~1.91). However, its X-ray spectrum is not well
fitted by either simple model, with the MCDBB model rejected at high
statistical significance. Two-component models incorporating a very soft
MCDBB plus a power-law continuum offered improvements to the fit, as
shown in Table 5, though only at the 69 and 94 per cent significance
levels in the first and second epochs respectively. A classic blackbody
component offered a superior improvement in the second epoch, at the 96
per cent significance level according to the F-statistic.
Curiously, a substantial improvement in the fit to the second-epoch
data was obtained when the MCDBB component was replaced with a MEKAL solar
abundance thermal plasma with kT~ 0.18 keV (Table 5). For two additional
free parameters, the reduction in {chi}^2^ of 23.3 implies a 99.99 per
cent significance level (i.e. >3.5{sigma}) in terms of the
F-test. Fig. 4 shows the resulting best-fitting spectrum and the
contribution of the MEKAL component. For comparison, a similar model
(power-law plus kT~ 0.18 keV MEKAL) was fitted to the first-epoch data
and no significant improvement to the best fit was obtained, with the
contribution of the putative thermal component limited to no more than 3
per cent of the 0.5-8 keV flux.
However, the MEKAL fit relies heavily on the fact that a blend of lines
between 0.5 and 0.75 keV (predominantly O VII and O VIII), when combined
with a factor ~2 increase in the model N_H_, gives a good match to the
additional soft emission apparent in the second-epoch spectrum. Is this
thermal component real or simply an artifact of fitting a fairly complex
model to data with limited spectral resolution and poor statistics
(N.B. ~600 counts out of ~2000 in the full spectrum originate from the
MEKAL component)? Clearly there is no direct evidence in the
second-epoch spectrum for individual lines (though this is perhaps
consistent with low temperature of the plasma and the >100 eV spectral
resolution of the ACIS-S detector below 1 keV). On the other hand, when
we allow the abundance of O, Ne and Fe (which produce the most
significant line features in the kT~ 0.18 keV plasma) to vary in the
VMEKAL model, we obtain a best fit of 1.3 solar and a 90 per cent lower
limit of 0.33 solar, implying that there is a strong preference for a
substantial contribution from emission lines. However, this is on the
basis of a spectral model that may not be correct. We conclude that an
interpretation of the additional soft flux present in the second epoch
in terms of the emergence of a bright thermal component is potentially
very interesting (see Section 5.3), albeit highly speculative.
Finally, we note that as this paper was undergoing the refereeing
process these Chandra spectra were published by Cropper et al. (2004) as
part of an XMM-Newton study of this source. They do not report the
possible detection of a MEKAL component, though they did not explicitly
look for it. Instead they fitted a particular model to the Chandra data,
based on fits to the superior quality (and later epoch) XMM-Newton
spectra, comprising a sub-solar-abundance absorber (TBVARABS, set at
0.31 times solar) applied to power-law plus blackbody emission
components. We have applied the Cropper et al. model, plus variants
incorporating soft MCDBB and MEKAL components, to the second-epoch
spectrum and do get a marginal improvement in each case with respect to
our original fits ({DELTA}{chi}^2^~ 2-4); nevertheless the power-law
plus MEKAL model still clearly provides the best result in terms of the
minimum {chi}^2^.

7. 2004MNRAS.349.1193R
Re:NGC 4559
4.2.5 CXOU J123558.6+275742 (NGC 4559 X-4) This object was the only ULX
in the sample with an X-ray spectrum clearly best fitted with a MCDBB
model. The inferred inner accretion disc temperatures were both greater
than 1 keV, consistent with previous ASCA and some Chandra observations
of ULX well fitted by this model (e.g. Colbert & Mushotzky 1999;
Makishima et al. 2000; Roberts et al. 2002). The luminosity of the ULX
more than doubles in the five months between observations, and this is
associated with a slight hardening of the X-ray spectrum, with the
best-fitting temperature of the inner accretion disc rising from ~1.1 to
~1.3 keV.

8. 2004MNRAS.349.1193R
Re:NGC 4559
A4 NGC 4559 X-1 (CXOU J123551.7+275604) and X-4 (CXOU J123558.6+275742)
NGC 4559 X-1 was first detected in the ROSAT All-Sky Survey bright
source catalogue as 1RXS J123551.6+275555 (Voges et al. 1999). It was
identified with the outer edge of the galactic disc of NGC 4559 by
Vogler, Pietsch & Bertoldi (1997), who present a detailed analysis of
the X-ray properties of this source based on a ROSAT PSPC pointed
observation. In their work, they refer to this source as NGC 4559
X-7. The PSPC profile of the source is point-like and no significant
X-ray variability was detected from it during the observation. Its
spectrum is well fitted by either a power-law continuum ({GAMMA}~ 3) or
thermal bremsstrahlung model (kT~ 0.8 keV), both showing absorption
N_H_~ 1-2 x 10^21^ atom cm^-2^, well in excess of the foreground
Galactic column. The observed (0.1-2.4 keV) luminosity of 2x10^39^ erg
s^-1^ converts to an impressive intrinsic luminosity of 1.5 x 10^40^ erg
s^-1^ using the thermal bremsstrahlung model. The PSPC position is
coincident with a group of emission knots in a faint outer spiral arm of
the galaxy, which Vogler et al. (1997) identify as likely H II
regions. It is, however, too bright to be the integrated X-ray emission
of ordinary X-ray binaries and supernova remnants associated with the H
II region. They conjecture that this source is most likely a supernova
remnant buried in a dense cloud of interstellar material, though they do
not rule out either a black hole accreting binary system or mini-AGN
from a merging dwarf galaxy, as alternative identifications. This source
was also detected, with a similar high X-ray luminosity, in a ROSAT HRI
observation (RW2000). Unlike NGC 4559 X-1, NGC 4559 X-4 was not
detected in the ROSAT All-Sky Survey bright source catalogue. However,
in the ROSAT PSPC observation reported by Vogler et al. (1997) (who list
this ULX as NGC 4559 X-10) it was brighter than X-1. It is located near,
but not at, the centre of the galaxy. It appears as an extended source
in the PSPC observation, with approximately 20 per cent of its flux
emanating from between 20 and 50 arcsec from the source centroid, which
may be a diffuse component, or confusion with other point sources (with
our Chandra data suggesting the latter). The X-ray spectrum is well
fitted by either a power-law continuum or thermal bremsstrahlung
emission, albeit spectrally harder in each case than for X-1 ({GAMMA}~
2.0 or kT~ 2.1 keV, respectively), with a measured absorption column of
N_H_~ 10^21^ atom cm^-2^. This gave an observed (intrinsic) luminosity
of 7(12) x 10^39^ erg s^-1^. Vogler et al. (1997) suggest that X-10 is
the superposition of several point sources, though they cannot rule out
the contribution of an AGN towards the observed flux. This source is
again also detected in the ROSAT HRI survey of RW2000, offset from the
nucleus of NGC 4559 by 13 arcsec.

9. 1994CAG1..B...0000S
Re:NGC 4559
Sc(s)II
PH-8003-S
Feb 2/3, 1981
103aO
12 min
NGC 4559 is nearby, judged by the ease of
resolution of the HII regions at about the 3" level
and the existence of what appear to be individual
stars starting at about B = 22 mag. The blue
image is given in the upper print here. The H{alpha}
interference filter image is below.
The redshift is v_o = 771 km/s.
[The illustrations in the Carnegie Atlas are
reversed: the bottom image is from the blue plate.]

10. 1994CAG1..B...0000S
Re:NGC 4559
Sc(s)II
PH-4516-S
April 14/15, 1964
H{alpha} interference filter
120 min
The largest of the individual HII regions in
NGC 4559 resolve at about the 3" level. The
arms are not as well defined as in the continuum
blue image in the print above.
[The illustrations in the Carnegie Atlas are
reversed: the top image is from the H{alpha} plate.]

11. 1993A&AS...97..887B
Re:NGC 4559
NGC 4559
The central CO width is much less than the HI width, despite the
inclination. Along the major axis (NW), we only have an uncertain
detection which does not allow us to calculate the total molecular mass.

12. 1976RC2...C...0000d
Re:NGC 4559
= Holm 423a
3 small anonymous galaxies nearby (Holm 423b,c,d).
Photograph:
Ap. J., 194, 559, 1974.
Photometry and Isodensitometry:
Ap. J. Suppl., 26, No. 230, 1973.
HII Regions and Distance Modulus:
Ap. J., 194, 559, 1974.
SN1941A.
Ann.Rev.Ast.Ap., 2, p.249, 1964.
"Supernovae & SN Remnants", Ap. & Space Sc. Lib., 45, p.207, 1974.

13. 1973UGC...C...0000N
Re:UGC 07766
SAB(rs)cd (de Vaucouleurs), Sc+ (Holmberg)
SN 1941a
I 3550, I 3551, I 3552, I 3554, I 3555, I 3563, I 3564 are condensations in
this galaxy

14. 1964RC1...C...0000d
Re:NGC 4559
= Holm 423a
3 small anonymous nearby galaxies (= Holm 423b,c,d)
Very small, not very bright nucleus in a short bar. Pseudo (r): 1.1 arcmin x
0.55 arcmin. Several, partially resolved, filamentary, branching arms.
SN 1941
H.A.C. 576.
P.A.S.P., 53, 130, 1941.
P.A.S.P., 53, 194, 1941.
Observatory, 68, 121, 1948.
HII Regions:
Zeit. fur Ap., 50, 168, 1960 (NGC 4459 is a misprint).

15. 1918PLicO..13....9C
Re:NGC 4559
Vol. VIII, Plate 39. A bright spiral '8' x 2' in p.a. 136^deg^. Faint, almost
stellar nucleus; numerous condensations in the rather irregular whorls. 26 s.n.


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