J/ApJ/704/385 M31 integrated light abundances (Colucci+, 2009)
M31 globular cluster abundances from high-resolution, integrated-light
spectroscopy.
Colucci J.E., Bernstein R.A., Cameron S., McWilliam A., Cohen J.G.
<Astrophys. J., 704, 385-414 (2009)>
=2009ApJ...704..385C 2009ApJ...704..385C
ADC_Keywords: Abundances ; Clusters, globular ; Equivalent widths ; Spectroscopy
Keywords: galaxies: abundances - galaxies: individual (M31) -
galaxies: star clusters - globular clusters: general
Abstract:
We report the first detailed chemical abundances for five globular
clusters (GCs) in M31 from high-resolution (R∼25000) spectroscopy of
their integrated light (IL). These GCs are the first in a larger set
of clusters observed as part of an ongoing project to study the
formation history of M31 and its GC population. The data presented
here were obtained with the HIRES echelle spectrograph on the Keck I
telescope and are analyzed using a new IL spectra analysis method that
we have developed. In these clusters, we measure abundances for Mg,
Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, and Ba, ages ≥10Gyr,
and a range in [Fe/H] of -0.9 to -2.2. As is typical of Milky Way GCs,
we find these M31 GCs to be enhanced in the α-elements Ca, Si,
and Ti relative to Fe.
Description:
For this work, we obtained high-resolution IL (integrated light)
spectra of the M31 GCs using the HIRES spectrograph on the Keck I
telescope over the dates 2006 September 10-14. We used the D3 decker,
which provides a slit size of 1.7"x7.0" and spectral resolution of
R=24000. The wavelength coverage of the HIRES spectra is approximately
3800-8300Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 5 M31 spectroscopically confirmed clusters
ew.dat 38 1095 Line parameters and integrated light equivalent
widths for M31 GCs (table 4 of the paper)
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See also:
J/MNRAS/402/803 : M31 globular cluster system (Peacock+, 2010)
J/A+A/508/1285 : Metallicity estimates of M31 globular clusters (Galleti+,
2009)
J/A+A/471/127 : New globular clusters in M31 (Galleti+, 2007)
J/AJ/133/2764 : M31 globular clusters structural parameters (Barmby+, 2007)
J/A+A/416/917 : Revised Bologna Catalog of M31 globular clusters (Galleti+,
2004)
J/AJ/123/2490 : RV and [Fe/H] of M31 globular cluster system (Perrett+, 2002)
J/AJ/122/2458 : M31 globular clusters from HST (Barmby+, 2001)
J/AJ/119/727 : M31 globular clusters photometry (Barmby+, 2000)
J/AcA/48/455 : Globular Clusters in M31 and M33 (Mochejska+, 1998)
J/AJ/114/1488 : Globulars in M31 (Holland+ 1997)
J/A+AS/116/447 : M31 globulars clusters ellipticities (Staneva+, 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Cl Cluster identification (GNNN-BNNN) from Barmby
et al. (2000, Cat. J/AJ/119/727,
<[BHB2000] NNN-NNN> in Simbad; with B part
before G)
11- 12 I2 h RAh Hour of right ascension (J2000)
14- 15 I2 min RAm Minute of right ascension (J2000)
17- 21 F5.2 s RAs Second of right ascension (J2000)
23 A1 --- DE- Sign of declination (J2000)
24- 25 I2 deg DEd Degree of declination (J2000)
27- 28 I2 arcmin DEm Arcminute of declination (J2000)
30- 33 F4.1 arcsec DEs Arcsecond of declination (J2000)
35- 39 F5.2 mag Vmag V-band magnitude
41- 44 F4.2 --- E(B-V) B-V color excess from Rich et al.
(2005AJ....129.2670R 2005AJ....129.2670R )
45 A1 --- r_E(B-V) [g] g: from Fan et al. (2008MNRAS.385.1973F 2008MNRAS.385.1973F)
47- 51 F5.2 mag VMtot V0, dereddened total absolute magnitude (1)
53- 57 F5.2 kpc Rgc Galactocentric radius from Perrett et al.
(2002, Cat. J/AJ/123/2490)
59- 63 F5.2 [-] [Fe/H] Low-resolution spectroscopic metallicities of
Huchra et al. (1991ApJ...370..495H 1991ApJ...370..495H)
65- 68 F4.2 [-] e_[Fe/H] Uncertainty in [Fe/H]
70- 73 F4.2 [-] [a/Fe] ? Low-resolution [α/Fe] of Puzia et al.
2005A&A...434..909P 2005A&A...434..909P
75- 78 F4.2 [-] e_[a/Fe] ? Uncertainty in [a/Fe]
80- 83 F4.2 --- HBR ? Horizontal branch morphology ratios (HBRs) (2)
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Note (1): Reddening corrected and using a distance modulus for M31 of
(m-M)=24.47 (Holland 1998AJ....115.1916H 1998AJ....115.1916H)
Note (2): HBRs defined as the "Mironov index"=B/B+R, where B and R
correspond to the number of horizontal branch stars bluer or redder
than V-I=0.5 in the observed CMD of Rich et al. (2005AJ....129.2670R 2005AJ....129.2670R)
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Byte-by-byte Description of file: ew.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Cl Cluster identification (GNNN)
6- 10 A5 --- Ion Species identification (1)
12- 19 F8.3 0.1nm lambda Wavelength in Angstroms λ
21- 25 F5.3 eV ExPot Excitation potential
27- 32 F6.3 [-] log(gf) Log of the oscillator strength
34- 38 F5.1 10-13m EW ? Equivalent width (in mÅ)
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Note (1): Lines listed twice correspond to those measured in adjacent orders
with overlapping wavelength coverage.
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History:
From electronic version of the journal
References:
McWilliam & Bernstein. Paper I. 2008ApJ...684..326M 2008ApJ...684..326M
Colucci et al. Paper III. 2011ApJ...735...55C 2011ApJ...735...55C Cat. J/ApJ/735/55
Colucci et al. Paper IV. 2012ApJ...746...29C 2012ApJ...746...29C
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Nov-2011