J/A+A/613/A56 Spectroscopy of globular clusters (Larsen+, 2018)
Detailed abundance analysis of globular clusters in the Local Group:
NGC 147, NGC 6822, and Messier 33.
Larsen S. S., Brodie J. P., Wasserman, A., Strader J.
<Astron. Astrophys. 613, A56 (2018)>
=2018A&A...613A..56L 2018A&A...613A..56L (SIMBAD/NED BibCode)
ADC_Keywords: Abundances ; Abundances, [Fe/H] ; Clusters, globular ;
Spectroscopy
Keywords: galaxies: stars clusters: general - galaxies: abundances -
galaxies: individual: NGC 147 - galaxies: individual: NGC 6822 -
galaxies: individual: M33
Abstract:
We present new abundance measurements for eleven GCs in the Local
Group galaxies NGC 147, NGC 6822, and Messier 33. These are combined
with previously published observations of four GCs in the Fornax and
WLM galaxies. The abundances were determined from analysis of
integrated-light spectra, obtained with HIRES on the Keck I telescope
and with UVES on the VLT. We find that the clusters with [Fe/H]←1.5
are all alpha-enhanced at about the same level as Milky Way GCs. Their
Na abundances are also generally enhanced relative to Milky Way halo
stars, suggesting that these extragalactic GCs resemble their Milky
Way counterparts in containing significant fractions of Na-rich stars.
For [Fe/H]>-1.5, the GCs in M33 are also alpha-enhanced, while the GCs
that belong to dwarfs (NGC 6822 SC7 and Fornax 4) have closer to
Solar-scaled alpha-element abundances. The abundance patterns in SC7
are remarkably similar to those in the Galactic GC Ruprecht 106,
including significantly sub-solar [Na/Fe] and [Ni/Fe] ratios.
In NGC 147, the GCs with [Fe/H]←2.0 account for about 6% of the total
luminosity of stars in the same metallicity range, a lower fraction
than those previously found in the Fornax and WLM galaxies, but
substantially higher than in the Milky Way halo.
Description:
New observations of globular clusters in NGC 147 and NGC 6822 were
obtained with the HIRES spectrograph on the Keck I telescope on 5 Oct
2015 and 25 Sep 2016.
We also include older HIRES observations of four GCs in M33. The
spectra are the same as those used by Larsen et al.
(2002AJ....124.2615L 2002AJ....124.2615L).
In addition to the HIRES observations, we include our previously
published VLT/UVES spectra of GCs in the Fornax and WLM galaxies
(Larsen et al. 2012A&A...546A..53L 2012A&A...546A..53L, 2014A&A...565A..98L 2014A&A...565A..98L) and we refer
to our previous papers for details on the observational strategy and
data reduction.
These tables contain the individual abundance measurements for each
cluster.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 90 16 Log of observations
tablea1.dat 36 89 Abundances for NGC 147 Hodge II
tablea2.dat 36 89 Abundances for NGC 147 Hodge III
tablea3.dat 36 88 Abundances for NGC 147 PA-1
tablea4.dat 36 89 Abundances for NGC 147 PA-2
tablea5.dat 36 89 Abundances for NGC 147 SD7
tablea6.dat 36 90 Abundances for NGC 6822 SC6
tablea7.dat 36 89 Abundances for NGC 6822 SC7
tablea8.dat 36 87 Abundances for M33 H38
tablea9.dat 36 88 Abundances for M33 M9
tablea10.dat 36 88 Abundances for M33 R12
tablea11.dat 36 88 Abundances for M33 U49
tablea12.dat 36 65 Abundances for WLM GC
tablea13.dat 36 67 Abundances for Fornax 3
tablea14.dat 36 67 Abundances for Fornax 4
tablea15.dat 36 67 Abundances for Fornax 5
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Cluster Cluster name
14- 17 F4.1 mag Vmag ? Integrated visual magnitude
19 A1 --- r_Vmag Reference for Vmag (1)
21- 31 A11 "DD/MMM/YYYY" Date Observation date
33- 41 A9 s Texp Exosure time
43- 46 I4 km/s HRV ? Heliocentric radial velocity
48- 50 F3.1 km/s sigma ? One-dimensional velocity dispersion,
corrected for instrumental resolution
52- 63 A12 --- Table Name of the table with abundances
65- 90 A26 --- SName Simbad name
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Note (1): References as follows:
1 = Larsen et al. (2002AJ....124.2615L 2002AJ....124.2615L)
2 = Veljanoski et al. (2013MNRAS.435.3654V 2013MNRAS.435.3654V)
3 = Veljanoski et al. (2015MNRAS.452..320V 2015MNRAS.452..320V)
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Byte-by-byte Description of file: tablea*.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- El Element ratio
9- 14 F6.1 0.1nm lambda1 Starting wavelength of spectral window
16- 21 F6.1 0.1nm lambda2 Ending wavelength of spectral window
23 A1 --- l_Abd Limit flag on Abd
24- 29 F6.3 [-] Abd ?=-9.999 Abundance (dex) (1)
31- 36 F6.3 [-] e_Abd ?=-9.999 Abundance error (dex) (2)
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Note (1): A value of -9.999 indicates that the fit did not converge.
Note (2): A value of -9.999 indicates that the fit did not converge
or that only an upper limit could be determined.
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Acknowledgements:
Soeren Larsen, s.larsen(at)astro.ru.nl
(End) Soeren Larsen [Radboud University], Patricia Vannier [CDS] 11-Jan-2018