J/MNRAS/360/185 VI photometry of the Leo II galaxy (Bellazzini+, 2005)
The red giant branch tip and bump of the Leo II dwarf spheroidal galaxy.
Bellazzini M., Gennari N., Ferraro F.R.
<Mon. Not. R. Astron. Soc., 360, 185-193 (2005)>
=2005MNRAS.360..185B 2005MNRAS.360..185B
ADC_Keywords: Galaxies, photometry ; Photometry, CCD ; Photometry, UBVRI
Keywords: stars: Population II - galaxies: distances and redshifts -
Local Group - variable stars: RR Lyrae
Abstract:
We present V and I photometry of a 9.4'x9.4' field centered on the
dwarf spheroidal galaxy Leo II. The Tip of the Red Giant Branch is
identified at ITRGB=17.83±0.03 and adopting <[M/H]≥-1.53±0.2
from the comparison of RGB stars with Galactic templates, we obtain a
distance modulus (m-M)_0=21.84±0.13, corresponding to a distance
D=233±15kpc. Two significant bumps have been detected in the
Luminosity Function of the Red Giant Branch. The fainter bump (B1, at
V=21.79±0.05) is the RGB bump of the dominant stellar population
while the brightest one (B2, at V=21.36±0.05) may be identified as
the Asymptotic Giant Branch Clump of the same population. The
luminosity of the main RGB bump (B1) suggest that the majority of RGB
stars in Leo II belongs to a population that is ≳4Gyr younger than
the classical Galactic globular clusters. The stars belonging to the
He-burning Red Clump are shown to be significantly more centrally
concentrated than RR Lyrae and Blue Horizontal Branch stars, probing
the existence of an age/metallicity radial gradient in this remote
dwarf spheroidal.
Description:
V and I photometry and astrometry for 2715 stars in a 9.4'x9.4' field
centered on the Leo II dwarf spheroidal galaxy. Photometric system:
Johnson-Kron-Cousins (Landolt's photometric standards).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 77 2716 Leo II stars positions and magnitudes
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See also:
J/MNRAS/354/708 : Leo I VI photometry (Bellazzini+, 2004)
J/AJ/120/284 : Variables in Leo II dwarf spheroidal (Siegel+, 2000)
J/MNRAS/261/657 : Deep CCD photometry of Leo II (Demers+ 1993)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Identification number
6- 11 F6.3 mag Vmag Johnson V magnitude
13- 17 F5.3 mag e_Vmag Uncertainty on V magnitude (DoPHOT)
19- 24 F6.3 mag Icmag Cousins I magnitude
26- 30 F5.3 mag e_Icmag Uncertainty on Ic magnitude (DoPHOT)
32- 38 F7.2 pix xpos x position in the frame
40- 46 F7.2 pix ypos y position in the frame
48- 49 I2 h RAh Right ascension (J2000.0)
51- 52 I2 min RAm Right ascension (J2000.0)
54- 59 F6.3 s RAs Right ascension (J2000.0)
61 A1 --- DE- Declination sign (J2000.0)
62- 63 I2 deg DEd Declination (J2000.0)
65- 66 I2 arcmin DEm Declination (J2000.0)
68- 72 F5.2 arcsec DEs Declination (J2000.0)
74- 77 A4 ----- [SM2000] Variable star name according to Siegel &
Majewski, 2000, Cat. J/AJ/120/284
(except V173, this paper)
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Acknowledgements: Michele Bellazzini, michele.bellazzini(at)bo.astro.it
(End) Michele Bellazzini [INAF-OAB, Italy], Patricia Vannier [CDS] 27-Jun-2005