J/ApJ/659/1198 ARAUCARIA project: NGC 3109 blue supergiants (Evans+, 2007)
The ARAUCARIA project: VLT-FORS spectroscopy of blue supergiants in NGC 3109.
Classifications, first abundances, and kinematics.
Evans C.J., Bresolin F., Urbaneja M.A., Pietrzynski G., Gieren W.,
Kudritzki R.-P.
<Astrophys. J., 659, 1198-1211 (2007)>
=2007ApJ...659.1198E 2007ApJ...659.1198E
ADC_Keywords: Galaxies, nearby ; Stars, supergiant ; Stars, luminous ;
Stars, blue ; Radial velocities
Keywords: galaxies: individual (DDO 236, NGC 3109) - galaxies: stellar content -
stars: early-type - stars: fundamental parameters
Abstract:
We have obtained multiobject spectroscopy of luminous blue supergiants
in NGC 3109, a galaxy at the periphery of the Local Group at ∼1.3Mpc.
We present a detailed catalog including finding charts, V and I
magnitudes, spectral classifications, and stellar radial velocities.
The radial velocities are seen to trace the rotation curves obtained
from studies of the H I gas. From quantitative analysis of eight
B-type supergiants we find a mean oxygen abundance of
12+log(O/H)=7.76±0.07 (1σ systematic uncertainty), with a
median result of 7.8. Given its distance, we highlight NGC 3109 as
the ideal example of a low-metallicity, dark-matter-dominated dwarf
galaxy for observations with the next generation of ground-based
extremely large telescopes.
Description:
The data were taken with the FORS2 (focal-reducer, low-dispersion
spectrograph) instrument at the VLT on 2004 February 24 and 25. The
multiobject spectroscopy with moveable slits (MOS) mode of operation
was used with the 600B grism for the blue-region observations and the
1200R grism in the red.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 93 91 Observational parameters of target stars
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See also:
J/ApJ/648/366 : Araucaria: NGC 3109 Cepheids VI phot. (Pietrzynski+, 2006)
J/ApJ/648/375 : Araucaria: NGC 3109 Cepheids JK phot. (Soszynski+, 2006)
J/A+A/466/75 : PN and HII regions of West and East of NGC 3109 (Pena+, 2007)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Star sequential number
4 I1 -- Field [1/4] Field number
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 16 F5.2 s RAs Right ascension (J2000.0)
18 A1 --- DE- Declination sign (J2000.0)
19- 20 I2 deg DEd Declination (J2000.0)
22- 23 I2 arcmin DEm Declination (J2000.0)
25- 29 F5.2 arcsec DEs Declination (J2000.0)
31- 35 F5.2 mag Vmag Johnson V magnitude
37- 41 F5.2 mag V-Ic ?=- Johnson-Cousins V-I colour index
43- 55 A13 --- SpType MK spectral type
57- 59 I3 km/s RV ?=- Radial velocity
61- 63 I3 km/s e_RV ?=- 1-σ uncertainty of RV
65- 66 I2 --- Nl ?=- Number of lines used for RV
68- 70 I3 --- S/N ?=- Signal-to-noise ratio
72- 93 A22 --- Com Comments (1)
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Note (1): References for other names as follows:
DKI = Demers et al., 1985AJ.....90.1967D 1985AJ.....90.1967D, DKI NNNN
SC88 = Sandage and Carlson, 1988AJ.....96.1599S 1988AJ.....96.1599S, [SC88] ANNN
MRS07 = Pena et al. 2007, Cat. J/A+A/466/75, [PRS2007] HII NN
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Jun-2010