J/MNRAS/466/2006 Phoenix dwarf galaxy RV and [Fe/H] catalog (Kacharov+, 2017)
Prolate rotation and metallicity gradient in the transforming dwarf galaxy
Phoenix.
Kacharov N., Battaglia G., Rejkuba M., Cole A.A., Carrera R.,
Fraternali F., Wilkinson M.I., Gallart C.G., Irwin M., Tolstoy E.
<Mon. Not. R. Astron. Soc. 466, 2006 (2017)>
=2017MNRAS.466.2006K 2017MNRAS.466.2006K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Galaxies, rotation ; Stars, giant ;
Stars, late-type ; Abundances, [Fe/H] ; Radial velocities ;
Spectroscopy
Keywords: techniques: spectroscopic - galaxies: dwarf -
galaxies: kinematics and dynamics - Local Group -
galaxies: stellar content
Abstract:
Transition type dwarf galaxies are thought to be systems undergoing
the process of transformation from a star-forming into a passively
evolving dwarf, which makes them particularly suitable to study
evolutionary processes driving the existence of different dwarf
morphological types. Here we present results from a spectroscopic
survey of ∼200 individual red giant branch stars in the Phoenix dwarf,
the closest transition type with a comparable luminosity to
'classical' dwarf galaxies. We measure a systemic heliocentric
velocity Vhelio=-21.2±1.0km/s. Our survey reveals the clear presence
of prolate rotation that is aligned with the peculiar spatial
distribution of the youngest stars in Phoenix. We speculate that both
features might have arisen from the same event, possibly an accretion
of a smaller system. The evolved stellar population of Phoenix is
relatively metal-poor (<[Fe/H]≥-1.49±0.04dex) and shows a large
metallicity spread (sigma[Fe/H]=0.51±0.04dex), with a pronounced
metallicity gradient of -0.13±0.01dex/arcmin similar to luminous,
passive dwarf galaxies. We also report a discovery of an extremely
metal-poor star candidate in Phoenix and discuss the importance of
correcting for spatial sampling when interpreting the chemical
properties of galaxies with metallicity gradients. This study presents
a major leap forward in our knowledge of the internal kinematics of
the Phoenix transition type dwarf galaxy and the first wide area
spectroscopic survey of its metallicity properties.
Description:
This catalogue provides photometry, radial velocities, metallicities,
and the Ca triplet (CaT) equivalent widths of 228 stars in the field
of the Phoenix dwarf galaxy observed with the FORS2 spectrograph at
the VLT. 194 stars are confirmed Phoenix members.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
phxcat.dat 114 228 The catalogue
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See also:
J/MNRAS/424/1113 : VI photometry in Phoenix dwarf galaxy (Battaglia+, 2012)
Byte-by-byte Description of file: phxcat.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Photometric ID (1)
10- 18 F9.6 deg RAdeg Right ascension (J2000) (1)
20- 29 F10.6 deg DEdeg Declination (J2000) (1)
31- 35 F5.2 mag Vmag V band magnitude (1)
37- 40 F4.2 mag e_Vmag rms uncertainty on Vmag (1)
42- 46 F5.2 mag Imag I band magnitude (1)
48- 51 F4.2 mag e_Imag rms uncertainty on Imag (1)
53- 59 F7.2 km/s HRV ?=999.99 Heliocentric radial velocity
61- 66 F6.2 km/s e_HRV ?=99.99 rms uncertainty on HRV
68- 72 F5.2 --- [Fe/H] ?=9.99 Metallicity
74- 77 F4.2 --- e_[Fe/H] ?=9.99 rms uncertainty on [Fe/H]
79- 82 F4.2 0.1nm EW1 Equivalent width of the first CaT line
84- 87 F4.2 0.1nm e_EW1 rms uncertainty on EW1
89- 92 F4.2 0.1nm EW2 Equivalent width of the second CaT line
94- 97 F4.2 0.1nm e_EW2 rms uncertainty on EW2
99-102 F4.2 0.1nm EW3 Equivalent width of the third CaT line
104-107 F4.2 0.1nm e_EW3 rms uncertainty on EW3
109-110 I2 --- SNR Signal to noise per pixel
112-114 A3 --- Memb [yes/no ] Member of Phx
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Note (1): From Battaglia et al., 2012, Cat. J/MNRAS/424/1113
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Acknowledgements:
Nikolay Kacharov, kacharov(at)mpia.de
(End) Nikolay Kacharov [MPIA, Germany], Patricia Vannier [CDS] 23-Jan-2017