J/MNRAS/386/826 Radial velocities of SMC massive stars (Evans+, 2008)
Kinematics of massive stars in the Small Magellanic Cloud.
Evans C.J., Howarth I.D.
<Mon. Not. R. Astron. Soc. 386, 826 (2008)>
=2008MNRAS.386..826E 2008MNRAS.386..826E
ADC_Keywords: Magellanic Clouds ; Radial velocities ; Stars, early-type
Keywords: galaxies: kinematics and dynamics - galaxies: Magellanic Clouds -
stars: early-type - stars: fundamental parameters
Abstract:
We present radial velocities for 2045 stars in the Small Magellanic
Cloud (SMC), obtained from the 2dF survey by Evans et al. (2004, Cat.
J/MNRAS/353/601). The great majority of these stars are of OBA type,
tracing the dynamics of the young stellar population. Dividing the
sample into ad hoc `bar' and `wing' samples (north and south,
respectively, of the line: delta=-77^°50' + [4α]', where
alpha is in minutes of time) we find that the velocities in the SMC
bar show a gradient of 26.3±1.6km/s/deg at a position angle of
126±4deg. The derived gradient in the bar is robust to the adopted
line of demarcation between the two samples. The largest redshifts are
found in the SMC wing, in which the velocity distribution appears
distinct from that in the bar, most likely a consequence of the
interaction between the Magellanic Clouds that is predicted to have
occurred 0.2Gyr ago. The mean velocity for all stars in the sample is
+172.0±0.2km/s (redshifted by ∼20km/s when compared to published
results for older populations), with a velocity dispersion of 30km/s.
Description:
Stellar radial velocities for 2045 stars in the Small Magellanic
Cloud.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
rv.dat 82 2045 Stellar radial velocities from the SMC 2dF survey
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See also:
J/MNRAS/353/601 : 2dF survey of the Small Magellanic Cloud (Evans+, 2004)
Byte-by-byte Description of file: rv.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Name 2dFS serial number (1)
6- 7 I2 h RAh Right Ascension J2000 (hours)
10- 11 I2 min RAm Right Ascension J2000 (minutes)
14- 18 F5.2 s RAs Right Ascension J2000 (seconds)
21 A1 --- DE- Declination J2000 (sign)
22- 23 I2 deg DEd Declination J2000 (degrees)
26- 27 I2 arcmin DEm Declination J2000 (minutes)
30- 33 F4.1 arcsec DEs [0/60] Declination J2000 (seconds)
37- 41 F5.2 mag Bmag Adopted B magnitude
45 A1 --- r_Bmag Source of adopted B magnitude (2)
50- 69 A20 --- SpType Adopted MK spectral subtype and luminosity class
72- 74 I3 km/s RV Stellar radial velocity
78- 79 I2 km/s e_RV Standard error on the mean of RV
82 I1 --- Nb Number of Balmer lines measured for each star
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Note (1): 2dFS identifications from Evans et al., 2004, Cat. J/MNRAS/353/601
Note (2): Sources of adopted B magnitudes as follows:
A = 2dF, Evans et al., 2004, Cat. J/MNRAS/353/601
M = Massey P., 2002ApJS..141...81M 2002ApJS..141...81M, Cat. II/236
O = OGLE, Udalski et al., 1998, Cat. J/AcA/48/147
Z = Zaritsky et al. 2002, Cat. J/AJ/123/855
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Acknowledgements:
Chris Evans, cje(at)roe.ac.uk
(End) Patricia Vannier [CDS] 08-Feb-2008