J/MNRAS/384/943 Velocities of NGC 1023 planetary nebulae (Noordermeer+, 2008)
Testing the nature of S0 galaxies using planetary nebula kinematics in NGC 1023.
Noordermeer E., Merrifield M.R., Coccato L., Arnaboldi M., Capaccioli M.,
Douglas N.G., Freeman K.C., Gerhard O., Kuijken K., De Lorenzi F.,
Napolitano N.R., Romanowsky A.J.
<Mon. Not. R. Astron. Soc., 384, 943-952 (2008)>
=2008MNRAS.384..943N 2008MNRAS.384..943N
ADC_Keywords: Galaxies, nearby ; Planetary nebulae ; Radial velocities
Keywords: galaxies: individual: NGC 1023 - galaxies: individual: NGC 1023A -
galaxies: elliptical and lenticular, cD - galaxies: structure -
galaxies: kinematics and dynamics - galaxies: evolution
Abstract:
We investigate the manner in which lenticular galaxies are formed by
studying their stellar kinematics: an S0 formed from a fading spiral
galaxy should display similar cold outer disc kinematics to its
progenitor, while an S0 formed in a minor merger should be more
dominated by random motions. In a pilot study to attempt to
distinguish between these scenarios, we have measured the planetary
nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the
Planetary Nebula Spectrograph, we have detected and measured the
line-of-sight velocities of 204 candidate PNe in the field of this
galaxy. Out to intermediate radii, the system displays the kinematics
of a normal rotationally-supported disc system. After correction of
its rotational velocities for asymmetric drift, the galaxy lies just
below the spiral galaxy Tully-Fisher relation, as one would expect for
a fading system. However, at larger radii the kinematics undergo a
gradual but major transition to random motion with little rotation.
This transition does not seem to reflect a change in the viewing
geometry or the presence of a distinct halo component, since the
number counts of PNe follow the same simple exponential decline as
the stellar continuum with the same projected disc ellipticity out to
large radii. The galaxy's small companion, NGC 1023A, does not seem
to be large enough to have caused the observed modification either.
This combination of properties would seem to indicate a complex
evolutionary history in either the transition to form an S0 or in the
past life of the spiral galaxy from which the S0 formed. More data
sets of this type from both spirals and S0s are needed in order to
definitively determine the relationship between these types of system.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 45 204 Catalogue of PNe in NGC 1023 and NGC 1023A
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See also:
J/ApJ/383/487 : Planetary nebulae as standard candles. VII. (Ciardullo+, 1991)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [NGC 1023]
10- 12 I3 --- [NMC2008] Object name ([NMC2008] NGC 1023 NNN in Simbad)
14 I1 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 23 F5.2 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 35 F4.1 arcsec DEs Declination (J2000)
37- 40 I4 km/s HV Heliocentric velocity
42- 43 I2 km/s e_HV rms uncertainty on HV
45 A1 --- n_HV [abc] Note on HV (1)
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Note (1): Notes as follows:
a = >3σ outlier in the tilted ring analysis
b = Discrepant velocity; unbound to system
c = Object statistically more likely to belong to companion NGC 1023A
than to main galaxy NGC 1023.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Jul-2008