J/MNRAS/335/233 Integrated Spectra of Open Clusters (Piatti+, 2002)
Integrated spectral evolution of Galactic open clusters.
Piatti A.E., Bica E., Claria J.J., Santos J.F.C.Jr, Ahumada A.V.
<Mon. Not. R. Astron. Soc. 335, 233 (2002)>
=2002MNRAS.335..233P 2002MNRAS.335..233P
ADC_Keywords: Spectrophotometry ; Clusters, open
Keywords: techniques: spectroscopic - open cluster and associations: general -
galaxies: individual: Milky Way - galaxies: star clusters
Abstract:
We present a library of 39 open cluster optical/near-IR integrated
spectra. The data were obtained at CASLEO (San Juan, Argentina) and
LNA (Itajuba, Brazil). Eight additional spectra obtained at ESO (La
Silla, Chile), also employed in the present analysis, are already
available at CDS (see cat. III/219). The data were combined in order
to derive high S/N templates of young and intermediate-age populations
sampling their evolutionary states with unprecedented time resolution
at nearly solar metallicity. These template spectra, also included in
the library, are useful, e.g., for population synthesis techniques
applied to galaxies and for estimates of individual cluster parameters
in the Milky Way as well as in external galaxies.
Description:
This catalogue contains 39 integrated spectra of Galactic open
clusters and 20 template spectra at 10 different ages. The clusters
individual spectra were presented in 10 papers previously published
and in the present one. The template spectrum representative of an age
group was built by averaging the integrated spectra in such group,
weighted by their squared S/N ratios. Given the number of objects with
similar properties, the template spectra have improved S/N and have
been built from linked individual spectra in order to cover a spectral
range as wider as possible. The 2 youngest templates were divided into
12 spectral groups mimicking different real spectral distributions
arising from dust (foreground and internal) and/or bright stellar
content varying stochastically (W-R stars and supergiants). The
spectra are corrected for foreground reddening and their resolution is
in the range 10-20Å with fluxes (W/m2/nm) normalized to 1 at
5870Å (except where indicated). The spectral range as well as the
mean reddening for each cluster are detailed in table clusters.dat.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
clusters.dat 64 47 List of clusters with spectral range observed
template.dat 100 20 List of template spectra with the covered age
range
refs.dat 58 11 References
spectra/* . 59 Spectra
--------------------------------------------------------------------------------
See also:
III/219 : Spectral Library of Galaxies, Clusters and Stars (Santos+, 2001)
Byte-by-byte Description of file: clusters.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Cluster Name of star cluster (G1)
13 A1 --- n_Cluster [*] Note (1)
15- 25 A11 --- Obs Observatory
26- 30 A5 --- r_Obs [A-K, ] Comma-separated list of references
32- 35 F4.2 mag E(B-V) Adopted reddening
38- 41 I4 0.1nm Range1 Spectral range
42 A1 --- --- [-]
43- 47 I5 0.1nm Range2 Spectral range
50- 64 A15 --- Note Note on spectrum
--------------------------------------------------------------------------------
Note (1): Individual notes:
Mel 105: spectrum is an average of data obtained at CASLEO
(Ahumada et al., 2000A&AS..141...79A 2000A&AS..141...79A) and ESO
(Santos & Bica, 1993MNRAS.260..915S 1993MNRAS.260..915S).
The last one (not corrected for reddening) is in the
catalogue III/219.
Westerlund 1: spectrum is normalized at 6000Å.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: template.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Template Name of template (G1)
13- 16 I4 Myr Age1 Group age range (lower limit)
18 A1 --- --- [-]
20- 23 I4 Myr Age2 ? Group age range (lower limit)
27- 90 A64 --- memb Group members
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- RefCode [A-K] Reference code
3- 21 A19 --- BibCode The 19-digit bibcode of the reference
23- 36 A14 --- Aut Author's name
38- 68 A31 --- Com Comments
--------------------------------------------------------------------------------
Byte-by-byte Description of file: spectra/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.1 0.1nm lambda Central wavelength for each pixel
10- 18 F9.7 W/m2/nm flux Normalized flux
--------------------------------------------------------------------------------
Global Notes;
Note (G1): All spectra are in the "spectra" subdirectory, as a file
named from the Cluster name or Template.
All template spectra in the visible range (approx. 3600-7000Å) For
the 2-4 and 5-10 Myr templates (Ya and Yb) a numeric character was
included in their names to differentiate cluster spectra corrected by
(1) mean cluster reddening (the one shown in clusters.dat) obtained
from colour-magnitude diagram analyses,
(2) individual foreground reddening from integrated spectroscopy, or
(3) foreground reddening calculated taking into account an averaged
internal reddening. Template spectra which contain WR and/or SG
features are also labelled accordingly.
--------------------------------------------------------------------------------
Acknowledgements: Joao Francisco C. Santos Jr.
(End) Patricia Bauer [CDS] 16-Sep-2002