J/A+A/509/A11 Hα emission-line objects in SMC clusters (Martayan+, 2010)
A slitless spectroscopic survey for Hα emission-line objects in SMC
clusters.
Martayan C., Baade D., Fabregat J.
<Astron. Astrophys. 509, A11 (2010)>
=2010A&A...509A..11M 2010A&A...509A..11M
ADC_Keywords: Magellanic Clouds ; Stars, emission ; Photometry, UBVRI ;
Photometry, infrared
Keywords: stars: early-type - stars: emission-line, Be -
stars: fundamental parameters - stars: evolution - Magellanic Clouds -
catalogs
Abstract:
Slitless CCD spectra were obtained covering the bulk (about 3 square
degrees) of the Small Magellanic Cloud. For Hα line-emission
twice as strong as the ambient continuum, the survey is complete to
spectral type B2/B3 on the main sequence. About 8120 spectra of 4437
stars were searched for emission lines in 84 open clusters, and 370
emission-line stars were found, among them at least 231 close to the
main sequence. For 176 of them, photometry is available from the OGLE
database. For comparison with a higher-metallicity environment, the
Galactic sample of the photometric Hα survey by McSwain & Gies
(2005, Cat. J/ApJS/161/118) was used. Among early spectral
sub-types, Be stars are more frequent by a factor ∼3-5 in the SMC than
in the Galaxy. The distribution with spectral type is similar in both
galaxies, i.e., not strongly dependent on metallicity. The fraction of
Be stars does not seem to vary with local star density. The Be
phenomenon mainly sets in towards the end of the main-sequence
evolution (this trend may be more pronounced in the SMC); but some Be
stars already form with Be-star characteristics. In small subsamples
(such as single clusters), even if they appear identical, the fraction
of emission-line stars can deviate drastically from the mean. In all
probability, the fractional critical angular rotation rate, OMC, is
one of the main parameters governing the occurrence of the Be
phenomenon. If the Be character is only acquired during the course of
evolution, the key circumstance is the evolution of OMC, which is not
only dependent on metallicity but differently so for different mass
ranges. As a result, even if the Be phenomenon is driven basically by
a single parameter (namely OMC), it can assume a complex
multi-parametric appearance. The large cluster-to-cluster differences,
which seem stronger than all other variations, serve as a caveat that
this big picture may undergo significant second-order modulations
(e.g., pulsations, initial angular momentum, etc).
Description:
The observations were carried out on September 25 and 26, 2002 with
the Wide Field Imager (WFI) attached to the 2.2m MPG Telescope
at ESO's observatory on Cerro La Silla in Chile. In its slitless
spectroscopic mode, the WFI has a roughly circular field of view of
diameter 0.31°, and the R50 grism has a dispersion of 54nm/mm
(0.811nm/pix); the nominal resolution at optimal focus and seeing
is 5.1nm at Hα.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 137 55 Emission-line stars in NGC 346, part 1
tablea2.dat 130 55 Emission-line stars in NGC 346, part 2
tableb1.dat 102 159 *Data for individual observations of open
clusters in the SMC
tableb2.dat 81 83 Details about the individual open clusters with
different observations merged
tableca.dat 132 266 SMC cluster stars cross-correlation WFI with
OGLE (Udalski et al., 1998, Cat. J/AcA/48/147)
(tables C1, C3, C5 and C7 of paper)
tablecb.dat 99 266 *SMC cluster stars corrected photometry and
classification (tables C2, C4, and C6 of paper)
tablec9.dat 88 49 Emission-line star from WFI without
identification in SC catalogues from OGLE
(Udalski et al. 1998, Cat. J/AcA/48/147)
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Note on tableb1.dat: Several open clusters were observed twice or three
times in different images at different locations
Note on tablecb.dat: using calibration from Lang (1992, Astrophysical data,
Planets and Stars, New York, Springer Verlag Eds)
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See also:
J/MNRAS/311/741 : SMC emission-line objects (Murphy+, 2000)
J/A+AS/102/451 : Emission-line stars and PNe in the SMC (Meyssonnier+ 1993)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- --- WFI[S11] NGC 346-
18- 19 I02 --- Seq [1/55] WFI[S11] NGC 346- number
22 I1 h RAh WFI right ascension (J2000)
24- 25 I2 min RAm WFI right ascension (J2000)
27- 32 F6.3 s RAs WFI right ascension (J2000)
34 A1 --- DE- WFI declination sign (J2000)
35- 36 I2 deg DEd WFI declination (J2000)
38- 39 I2 arcmin DEm WFI declination (J2000)
41- 45 F5.2 arcsec DEs WFI declination (J2000)
47 I1 h RA2.h ?=- 2MASS right ascension (J2000)
49- 50 I2 min RA2.m ?=- 2MASS right ascension (J2000)
52- 56 F5.2 s RA2.s ?=- 2MASS right ascension (J2000)
58 A1 --- DE2.- 2MASS declination sign (J2000)
59- 60 I2 deg DE2.d ?=- 2MASS declination (J2000)
62- 63 I2 arcmin DE2.m ?=- 2MASS declination (J2000)
65- 68 F4.1 arcsec DE2.s ?=- 2MASS declination (J2000)
70 I1 h RAe.h ?=- EIS right ascension (J2000)
72- 73 I2 min RAe.m ?=- EIS right ascension (J2000)
75- 80 F6.3 s RAe.s ?=- EIS right ascension (J2000)
82 A1 --- DEe.- EIS declination sign (J2000)
83- 84 I2 deg DEe.d ?=- EIS declination (J2000)
86- 87 I2 arcmin DEe.m ?=- EIS declination (J2000)
89- 93 F5.2 arcsec DEe.s ?=- EIS declination (J2000)
95-100 F6.3 mag Bmag ?=- EIS B magnitude
101 A1 --- n_Bmag [s] s when magnitude from Simbad
103-108 F6.3 mag Vmag EIS V magnitude
109 A1 --- n_Vmag [s] s when magnitude from Simbad
111-116 F6.3 mag Imag ?=- Denis I magnitude
118-123 F6.3 mag Jmag ?=- 2MASS J magnitude
125-130 F6.3 mag Hmag ?=- 2MASS H magnitude
132-137 F6.3 mag Kmag ?=- 2MASS K magnitude
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [NGC 346-]
9- 10 I02 --- Seq [1/55] WFI NGC 346- number
12- 22 A11 --- EIS EIS name (SMC5 NNNNNN)
24- 33 A10 --- OName Other name
35- 40 F6.3 mag B-V ? B-V colour index
42- 45 F4.2 mag E(B-V) Colour excess
47- 52 F6.3 mag (B-V)0 ? Deredenned B-V colour index
54- 58 F5.2 mag V0mag Deredenned V magnitude
60- 64 F5.2 mag VMAG Absolute V magnitude
66- 69 A4 --- SpT WFI spectral type
70 A1 --- n_SpT [*] *: not main-sequence
71- 81 A11 --- class Simbad spectral class
83- 92 A10 --- Vclass VFS (Hunter et al., 2008,
Cat. J/A+A/479/541) class
94-104 A11 --- Wclass WB07 (Wisniewski et al., 2007,
Cat. J/ApJ/671/2040) class
106-119 A14 --- Sclass Spitzer (Nota et al., 2006ApJ...640L..29N 2006ApJ...640L..29N)
class
121-130 A10 --- Hclass H08 (Hennekemper et al., 2008ApJ...672..914H 2008ApJ...672..914H)
class
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Cluster Cluster name (SMCNNN)
8- 9 I2 --- WFImg WFI image number
11 I1 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension 9J2000)
16- 20 F5.2 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 32 F4.1 arcsec DEs Declination (J2000)
34- 36 I3 arcsec r Radius (1)
38 A1 --- l_logt Limit flag on logt
39- 41 F3.1 [yr] logt Age (from Pietrzynski & Udalski,
1999AcA....49..157P 1999AcA....49..157P)
43- 44 A2 --- l_Z [≤ ] Limit flag on Z
45- 49 F5.3 --- Z Area of metallicity (from Cioni et al.,
2006A&A...452..195C 2006A&A...452..195C)
50 A1 --- --- [-]
51- 55 F5.3 --- Z2 ? Area of metallicity (from Cioni et al.,
2006A&A...452..195C 2006A&A...452..195C)
57- 59 I3 --- N* Total number of stars/spectra extracted
61- 62 I2 --- Nem Number of definite emission-line stars found
64 I1 --- Nem? Number of candidate emission-line stars found
66- 67 I2 --- Nem+ Total number of (definite+candidate) emission
line stars
69- 72 F4.1 % em/t Proportion in % of emission-line stars to the
whole sample by open cluster
74- 76 I3 --- O* OGLE Total number of stars/spectra
extracted (2)
78- 79 I2 --- Oem OGLE Number of definite emission-line stars
found (2)
81 I1 --- Oem? OGLE Number of candidate emission-line stars
found (2)
83- 90 A8 --- Comm Comments (3)
92- 96 F5.1 --- N OGLE/WFI Total number of stars/spectra
extracted
98-102 F5.1 --- ELS ? OGLE/WFI Number of definite emission-line
stars found
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Note (1): The radii used in this study is generally equal to 1.5x
the radii from Pietrzynski & Udalski (1999AcA....49..157P 1999AcA....49..157P).
Note (2): Number of stars for each category found in OGLE catalogues
(Udalski et al., 1998, Cat. J/AcA/48/147).
Note (3): Comments as follows:
1 = SMC17 and SMC18 have common stars since it appears to be
a binary cluster
2 = The extracted spectrum of the candidate emission-line star
is a blend of 2 emission-line stars spectra
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Byte-by-byte Description of file: tableb2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Cluster Cluster name (SMCNNN)
8- 10 I3 --- On* OGLE number of normal stars
12- 13 I2 --- Oem OGLE number of emission-line stars
15 I1 --- Oem? OGLE number of candidate emission-line stars
17- 18 I2 --- Nem Number of emission-line stars not from OGLE
20- 23 F4.1 % ELS/all Ratio of emission-line to all stars
25- 26 I2 --- Be ? Number of Be stars
28 I1 --- Be? ? Number of candidate Be stars
30- 31 I2 --- B ? Number of B stars
33- 37 F5.2 % Be/B ? Ratio of Be to all B stars
39- 44 F6.2 % Be+/B ? Ratio of (Be + candidate Be) to all b stars
46 I1 --- Oe ? Number of Oe stars
48 I1 --- O ? Number of O stars
50- 55 F6.2 % Oe/O ? Ratio of Oe to all O stars
57 I1 --- Ae ? Number of Ae stars
59- 60 I2 --- A ? Number of A stars
61- 66 F6.2 % Ae/A ? Ratio of Ae to all A stars
68- 69 I2 --- OBAe ? Number of emission-line stars (Oe, Be and Ae)
71- 73 I3 --- OBA ? Number of all O, B and A stars
75- 79 F5.2 --- OBAe/OBA ? Ratio of OBA emissions stars to all OBA stars
81 I1 --- F-Me ? Number of emission-line stars from main
sequence but not OBA type
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Byte-by-byte Description of file: tableca.dat
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Bytes Format Units Label Explanations
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1 I1 --- Code [1/4] Code for object type (G1)
3- 8 A6 --- Cluster Cluster name (SMCNNN)
10- 11 I2 --- WFImg WFI image number
13- 16 A4 --- OGLEimg OGLE image number
18- 22 I5 --- WFI WFI sequential number
24- 29 I6 --- OGLE OGLE sequential number
31- 33 F3.1 arcsec Rad Distance between OGLE and WFI positions
35 I1 h RAh WFI right ascension (J2000)
37- 38 I2 min RAm WFI right ascension (J2000)
40- 45 F6.3 s RAs WFI right ascension (J2000)
47 A1 --- DE- WFI declination sign (J2000)
48- 49 I2 deg DEd WFI declination (J2000)
51- 52 I2 arcmin DEm WFI declination (J2000)
54- 59 F6.3 arcsec DEs WFI declination (J2000)
61 I1 h RA2h OGLE right ascension (J2000)
63- 64 I2 min RA2m OGLE right ascension (J2000)
66- 71 F6.3 s RA2s OGLE right ascension (J2000)
73 A1 --- DE2- OGLE declination sign (J2000)
74- 75 I2 deg DE2d OGLE declination (J2000)
77- 78 I2 arcmin DE2m OGLE declination (J2000)
80- 85 F6.3 arcsec DE2s OGLE declination (J2000)
87- 92 F6.3 mag Vmag V magnitude
94- 99 F6.3 mag Bmag ?=99.999 B magnitude
101-106 F6.3 mag Imag I magnitude
108-113 F6.3 mag B-V ?=9.999 B-V colour index
115-120 F6.3 mag V-I V-I colour index
122-126 F5.3 mag E(B-V) Colour excess
128-130 F3.1 [yr] logt Age
132 I1 --- Mult Code for multiple WFI observations (1)
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Note (1): indicates whether the star is found several times as emission-
line star in case of different observations in WFI (different images).
1 means that the star was observed once (or the spectrum extracted once).
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Byte-by-byte Description of file: tablecb.dat
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Bytes Format Units Label Explanations
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1 I1 --- Code Code for object type (G1)
3- 8 A6 --- Cluster Cluster name (SMCNNN)
10- 11 I2 --- WFImg WFI image number
13- 17 I5 --- WFI WFI sequential number
19- 24 F6.3 mag (B-V)0 ? Corrected B-V colour index
26- 31 F6.3 mag V0mag Corrected V magnitude
33- 38 F6.3 mag VMAG Absolute V magnitude
40- 45 F6.3 mag (V-I)0 Corrected V-I colour index
47- 57 A11 --- SpT Spectral type
59- 83 A25 --- SName Simbad name
84 A1 --- u_SName [?] ? indicates a poor degree of confidence
on the identification in Simbad
86- 99 A14 --- Stype Simbad object type
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Byte-by-byte Description of file: tablec9.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Cluster Cluster name (SMCNNN)
8- 9 I2 --- WFImg WFI image number
11- 15 I5 --- WFI WFI sequential number
17 I1 h RAh WFI right ascension (J2000)
19- 20 I2 min RAm WFI right ascension (J2000)
22- 27 F6.3 s RAs WFI right ascension (J2000)
29 A1 --- DE- WFI declination sign (J2000)
30- 31 I2 deg DEd WFI declination (J2000)
33- 34 I2 arcmin DEm WFI declination (J2000)
36- 41 F6.3 arcsec DEs WFI declination (J2000)
43- 47 F5.3 mag E(B-V) Colour excess
48- 50 F3.1 [yr] logt Age
52- 55 A4 --- Status Status (ELS or ELS?)
57- 81 A25 --- SName Simbad name
82 A1 --- u_SName [?] ? indicates a poor degree of confidence
on the identification in Simbad
84- 88 A5 --- Stype Simbad object type
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Global notes:
Note (G1): Code for type as follows:
1 = Be stars
2 = candidate Be stars
3 = Ae and Oe stars
4 = Other emission-line star (not main-sequence)
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Acknowledgements:
Christophe Martayan, cmartaya(at)eso.org
History:
* 03-Nov-2009: Original version
* 27-Mar-2010: Rewritten cluster names with leading zeroes (e.g. SMC002
instead of SMC2) in order to keep identical names between tables.
(End) Christophe Martayan [ESO], Patricia Vannier [CDS] 03-Nov-2009