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Notes for object NGC 2681

23 note(s) found in NED.


1. 2012ApJ...754...67F
Re:NGC 2681
NGC 2681 PSXT0..-Possibly a triple barred system (Erwin & Sparke 1999). In HST
F555W a dust spiral is seen, which extends all the way into the center. The
rotational velocity curve shows a shelf between ~=2 and ~=12". The outer radius
of the shelf region coincides with the bulge radius (r_b_ = 13.2"). Inward of 2"
the rotation curve drops quickly to zero. With decreasing radius, the velocity
dispersion rises from about 50 km s^-1^ to a value of ~=75 km s^-1^ at the bulge
radius. Toward smaller radii it first stays relatively constant but then shows a
step at about 5" and rises again inward of 2". The h_3_ moments are
anti-correlated with velocity in the region of the fast velocity rise but become
correlated in the velocity shelf region. The h_4_ moments show a double peak
feature in the radial range of 2-4".

2. 2006ApJ...647..140F
Re:NGC 2681
This galaxy (L1, SB0/a) has three point sources within its central kiloparsec.
The brightest point source is at the exact center and is detected in both the
soft and hard bands. This is reminiscent of NGC 1553, except that NGC 2681 has
more diffuse emission than NGC 1553. The spectrum of the central source is best
fitted by a two-temperature plasma model or a power-law plus a
single-temperature plasma model (see Table 3). The luminosity inferred from
these models is L_0.5-10 keV_ = 9.5 x 10^38^ ergs s^-1^. These fits do not
exclude the possibility that the central source is an LLAGN since circumnuclear
hot gas can give rise to the thermal component superposed on a power-law AGN
spectrum. This source was detected in the radio wave band (S_{nu}_ = 12.0 mJy at
1.49 GHz; Condon 1987), leading to log R_X_ = -2.1 (radio-loud). A broad
H{alpha} emission line was detected in the optical (Ho et al. 1997c), suggesting
that this source is an LLAGN. We estimated the total luminosity from the 2.5"
central region to be L_2-10 keV_ = 9.7 x 10^38^ ergs s^-1^ and the luminosity of
the AGN to be L2-10 keV = 1.8 x 10^38^ ergs s^-1^ (by integrating the power-law
component), which means that the potential AGN contributes only ~20% of the
total X-ray luminosity of the central kiloparsec. This indicates that the
contribution from stellar processes is dominant. The other 80% of the luminosity
comes from three other point sources in the central 2.5" region and diffuse
emission. This is consistent with estimates that the solar metallicity stellar
population of NGC 2681 was formed in a starburst episode about 1 Gyr ago
(Gonzalez Delgado et al. 2004; Cappellari et al. 2001; Burstein et al. 1988). An
intermediate-age (108-109 yr) population has also been detected in the nucleus
of this galaxy by Cid Fernandes et al. (2005).

3. 2006A&A...460...45G
Re:NGC 2681
NGC 2681 (UGC 4645). An unresolved nuclear source was clearly detected at hard
X-ray energies (Fig. 5). Satyapal et al. (2005), who made use of archival
Chandra ACIS observations of this galaxy, classed them as an AGN-LINER, and
derived kT = 0.73 keV and {GAMMA} = 1.57 for an apec plus power-law fit to the
nuclear spectrum. These values are in perfect agreement, within the errors, with
the parameters we derive for our best model (ME+PL) ({GAMMA} = 1.74 and kT =
0.66 keV, see Table 6), which we recall gives unacceptable values for {chi}^2^.

4. 2005MNRAS.362.1319L
Re:NGC 2681
NGC 2681. This has been found to be a triple barred galaxy by ES03 and by Erwin
& Sparke (1999), based on both ground-based and HST NICMOS images. All three
bars are detected also in this study, as minima in the q profile and as blobs in
the polar angle map. This galaxy also has a nearly round lens at the radius of
the secondary bar.

5. 2005MNRAS.362.1319L
Re:NGC 2681
NGC 2681. This galaxy also has, in addition to a bulge and a disc, three bars
and a lens, which in principle could all be taken into account in the
decomposition. We included only the two larger bars and the lens in the
decomposition. The secondary bar near to the nucleus (visible in the
non-rebinned image) has a surface brightness that is too close to the surface
brightness of the bulge to be taken into account in the decomposition, so that
the functions for the bulge and the secondary bar became degenerate.

6. 2004A&A...415..941E
Re:NGC 2681
NGC 2681: Wozniak et al. (1995) and Erwin & Sparke (1999). See Erwin &
Sparke (2003).

7. 2002PNAOJ...6..107M
Re:KUG 0849+515
Blue arms and disks with the red nuclear region.

8. 2002AJ....124..675C
Re:UGC 04645
LINER in early (S0/a) galaxy (Kinney et al. 1993) with an unusually
high FIR/radio flux ratio.

9. 2000ApJ...542..186N
Re:NGC 2681
NGC 2681.-FIRST lists a peak 20 cm flux density of 3.8 mJy beam^-1^ at
5" resolution, with extended emission in P.A. 35^deg^. We did not detect
this object at 2 cm. The UGC and RC3 do not list a P.A. for this galaxy,
as it is almost round.

10. 1997ApJS..112..391H
Re:NGC 2681
NGC 2681.--As for NGC 3031 (Filippenko & Sargent 1988; see also Fig. 1b), the
two [S II] lines seem to have different widths, although the relatively low S/N
of this wavelength region renders the fits somewhat uncertain. Despite the
similarity between the profiles of [N II] and [S II] {lambda}6731, the narrow
component of H{alpha} has a smaller width than either; this could partly arise
from imperfect subtraction of H{alpha} absorption, since an intermediate-age
stellar template had to be included in the final starlight model (Paper III).
The extended tail redward of [N II] {lambda}6583, apparently absent in [S II],
supports the reality of the broad H{alpha} component derived from the profile
fitting, but the actual parameters of the broad H{alpha} component are not well
constrained (Fig. 8g). The extra bump near 6523 A comes from an Fe I feature
that is stronger in one of the template galaxies (NGC 205) than in NGC 2681.

11. 1997ApJS..108..155G
Re:NGC 2681
NGC 2681 is a LINER in an S0 galaxy. The nuclear emission might be
extended. The circumnuclear region shows a ring of star formation at 14"
(600 pc) from the nucleus. The vertical spike from the nucleus in the
H{alpha} image is a difraction artifact from the secondary mirror spider,
and the faint broad background stripes at an angle are due to electronic
pickup noise during the readout.

12. 1996A&AS..118..461F
Re:NGC 2681
NGC 2681. It is difficult to identify unambiguously a secondary bar in this
galaxy, and the abundant dust seen in our BV RI-images could be responsible for
the apparent nuclear structure. Indeed, in the K-band, the innermost
ellipticity maximum is strongly decreased although still present. The primary
bar shows a significant isophote twisting (15^deg^-20^deg^ depending on the
band). The J - K colour map shows a blue Seyfert nucleus (as in Paper I) whose
J - K is roughly 0.5 mag. bluer than the surrounding region. As the size of
this nucleus is closed to the seeing value, we have displayed the colour map
obtained from convolved images with approximately 3".

13. 1994CAG1..B...0000S
Re:NGC 2681
Hubble Atlas, p. 9
Sa
(E,L,1/4)
PH-191-MH
May 13/14, 1950
103aO
30 min
NGC 2681 has broad, smooth, almost
circular arms of the MAS type. Dust in an almost
circular pattern is present close to the center,
nearly buried in the bulge on this print but shown
well on page 9 of the Hubble Atlas. This galaxy,
together with NGC 1302 (panel 70), are the
earliest Sa galaxies shown in the Hubble Atlas.
NGC 2681 is, however, not as early as the
galaxies shown on the preceding two pages, for
the reasons described there.

14. 1994CAG1..B...0000S
Re:NGC 2681
Sa
(E,L,1/4)
Hubble Atlas, p. 9
PH-191-MH
May 13/14, 1950
103aO
30 min
The print of NGC 2681 here, also
illustrated in the Hubble Atlas (p. 9), shows the
smooth outer arms to better advantage than the
positive print on panel 62. The galaxy is among
the earliest of the true Sa's in the RSA. The arcs
of arms are spiral and are better defined, albeit
broad and smooth, than in the embryonic-armed,
mixed-morphology S0/Sa galaxies on panels 59
and 60. The arms in NGC 2681 are multiple
rather than of the grand design type shown on the
next panel.

15. 1993ApJS...86....5K
Re:NGC 2681
NGC 2681; Sa, LINER.
Like other LINERs in the atlas, this early-type spiral galaxy (S0/a)
shows little evidence for nuclear activity in the UV spectrum (Heckman
1980).
Although detected in the radio, no compact source has been seen (van
der Kruit 1971; Condon 1987, Table 2). Analysis of the UV spectrum by
Burstein et al. (1988) led to the conclusion that the galaxy has some
residual star formation with major bursts about 1-2 Gyr ago.

16. 1993A&AS...97..887B
Re:NGC 2681
NGC 2681 was detected at KP by PR at a level much lower than our CO(1-0)
spectrum. The line profiles agree almost perfectly. Our line ratio is
surprisingly low and our CO(1-0) is at the limit of what beamsize
differences can explain so it is possible that our CO(1-0) line, for some
unknown reason, is overestimated. NGC 2681 is peculiar in other ways,
however. It was not detected in HI and has one of the higher
S_60_/S_100_ ratios of our sample, 0.62. C87 identified a half-arcminute
source responsible for most of the 20cm emission. The H{alpha} line was
not detected by Y89.

17. 1976RC2...C...0000d
Re:NGC 2681
Photometry (12 Color):
Ap. J., 145, 36, 1966.
Photometry (5 Color):
A.J., 73, 313, 1968.
HI 21cm:
Source R2 (Astr. Ap., 21, 103, 1972), quality D, rejected.

18. 1975ByuO...47....1A
Re:ARK 185
(= NGC 2681)
Bright galaxy of type Sa.
Radial velocity = +745 km/sec [HMS 1956].
Neutral color.

19. 1973UGC...C...0000N
Re:UGC 04645
{(R')}SAB(rs)0/a (de Vaucouleurs), Sa (Holmberg)
{UGC incorrectly notes "Pec". H. Corwin}

20. 1964RC1...C...0000d
Re:NGC 2681
Extremely bright nucleus in a smooth (r): 0.6 arcmin x 0.6 arcmin.
Faint whorls in a lens. Pseudo (R): 2.1 arcmin x 2.0 arcmin.
Photograph:
Ap. J., 104, 219, 1946.
Stockholm Ann., 14, 1942; 15, 1948.
Orientation:
Stockholm Ann., 15, No 4, 1948.
(Note: 200-inch photograph shows outer whorls to be of same sense as
the inner spiral pattern).

21. 1961Hubbl.B...0000S
Re:NGC 2681
Sa
PH-191-MH
May 13/14, 1950
103aO
30 min
Enlarged 4.1X
NGC 2681 and NGC 1302 (right) are the earliest Sa galaxies
shown in the atlas. NGC 2681 has two well defined
spiral arms in its central region. These arms, shown in
the insert, are very tightly wound about the nucleus. It
is probable that the region between the stubby arms and
the intense nucleus is filled with dust.
There is a faint and very poorly defined outer spiral
structure. The direction of unwinding of the spiral pat
tern is almost impossible to trace. NGC 2681 is discussed
by Lindblad and Brahde in Ap. J., 105, 211, 1946; they
give several pictures of the galaxy.

22. 1956AJ.....61...97H
Re:NGC 2681
HMS Note No. 052
Plate overexposed.
Early-type spectrum with strong hydrogen lines.

23. 1918PLicO..13....9C
Re:NGC 2681
Very bright, rather large nucleus, surrounded by bright nebulosity; farther
out, diameter about 0.7', is a strong, nearly perfect ring formed by the union
of two whorls; much fainter whorls outside this ring. 30 s.n.


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