J/MNRAS/426/975 Kinematics of NGC 2768 from planetary nebulae (Forbes+, 2012)
Radially extended kinematics in the S0 galaxy NGC 2768 from planetary nebulae,
globular clusters and starlight.
Forbes D.A., Cortesi A., Pota V., Foster C., Romanowsky A.J.,
Merrifield M.R., Brodie J.P., Strader J., Coccato L., Napolitano N.
<Mon. Not. R. Astron. Soc., 426, 975-982 (2012)>
=2012MNRAS.426..975F 2012MNRAS.426..975F
ADC_Keywords: Galaxies, nearby ; Planetary nebulae ; Rotational velocities ;
Velocity dispersion
Keywords: galaxies: elliptical and lenticular, cD -
galaxies: individual: NGC 2768 - galaxies: kinematics and dynamics
Abstract:
There are only a few tracers available to probe the kinematics of
individual early-type galaxies beyond one effective radius. Here we
directly compare a sample of planetary nebulae (PNe), globular
clusters (GCs) and galaxy starlight velocities out to approximately
four effective radii, in the S0 galaxy NGC 2768. Using a bulge-to-disc
decomposition of a K-band image we assign PNe and starlight to either
the disc or the bulge. We show that the bulge PNe and bulge starlight
follow the same radial density distribution as the red subpopulation
of GCs, whereas the disc PNe and disc starlight are distinct
components. We find good kinematic agreement between the three tracers
to several effective radii (and with stellar data in the inner
regions). Further support for the distinct nature of the two galaxy
components comes from our kinematic analysis. After separating the
tracers into bulge and disc components we find the bulge to be a
slowly rotating pressure-supported system, whereas the disc reveals a
rapidly rising rotation curve with a declining velocity dispersion
profile. The resulting Vrot/σ ratio for the disc resembles that
of a spiral galaxy and hints at an origin for NGC 2768 as a
transformed late-type galaxy. A two-component kinematic analysis for a
sample of S0s will help to elucidate the nature of this class of
galaxy.
Description:
Velocity data for 315 PNe in NGC 2768 were acquired using the PN.S
spectrograph (Douglas et al., 2002PASP..114.1234D 2002PASP..114.1234D) in 2007 and are
available at www.strw.leidenuniv.nl/pns/ and in Cortesi et al.,
Cat. J/A+A/549/A115.
The radial surface density distribution and velocity data for GCs come
from the imaging and spectroscopy of Pota et al.
(2013MNRAS.428..389P 2013MNRAS.428..389P).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 77 125 Galaxy kinematic data
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See also:
J/ApJ/635/290 : PNe and stellar kinematics in NGC1344 (Teodorescu+, 2005)
J/ApJS/175/522 : Catalog of PNe in NGC 4697 (Mendez+, 2008)
J/ApJ/691/228 : Velocities of PNe in NGC 4697 (Mendez+, 2009)
J/ApJ/721/369 : PNe in the elliptical galaxy NGC 821 (Teodorescu+, 2010)
J/ApJ/736/65 : PNe in Virgo elliptical galaxy NGC 4649 (Teodorescu+, 2011)
J/A+A/549/A115 : Planetary Nebula Spectrograph survey (Cortesi+, 2013)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Mask [Y1 Y2 Z] Mask identification (1)
4- 5 I2 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 15 F6.3 s RAs Right ascension (J2000)
17 A1 --- DE- declination sign (J2000)
18- 19 I2 deg DEd declination (J2000)
21- 22 I2 arcmin DEm declination (J2000)
24- 28 F5.2 arcsec DEs declination (J2000)
30- 34 F5.1 arcsec r [14/677] Galactocentric radius
36- 38 I3 deg PA Position angle
40- 43 I4 km/s Vobs Observed rotation velocity
45- 47 I3 km/s e_Vobs rms uncertainty on Vobs
49- 51 I3 km/s sigma Velocity dispersion σ
53- 55 I3 km/s e_sigma rms uncertainty on sigma
57- 61 F5.2 --- h3 h3 Gauss-Hermite coefficient (3rd-order moment)
63- 66 F4.2 --- e_h3 rms uncertainty on h3
68- 72 F5.2 --- h4 h4 Gauss-Hermite coefficient (4th-order moment)
74- 77 F4.2 --- e_h4 rms uncertainty on h4
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Note (1): The data for two individual masks are included (Y and Z); however,
mask Y has been observed twice independently and is labelled Y1 and Y2.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Apr-2013