J/A+A/584/A5 Massive LMC stars AAOmega spectroscopy (Evans+, 2015)
2dF-AAOmega spectroscopy of massive stars in the Magellanic Clouds:
The north-eastern region of the Large Magellanic Cloud.
Evans C.J., van Loon J.T., Hainich R., Bailey M.
<Astron. Astrophys. 584, A5 (2015)>
=2015A&A...584A...5E 2015A&A...584A...5E (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, B-type ; Binaries, spectroscopic
Keywords: Magellanic Clouds - stars: early-type -
stars: fundamental parameters -
open clusters and associations: general
Abstract:
We present spectral classifications from optical spectroscopy of 263
massive stars in the north-eastern region of the Large Magellanic
Cloud. The observed two-degree field includes the massive 30 Doradus
star-forming region, the environs of SN1987A, and a number of
star-forming complexes to the south of 30 Dor. These are the first
classifications for the majority (203) of the stars and include eleven
double-lined spectroscopic binaries. The sample also includes the
first examples of early OC-type spectra (AAOmega 30 Dor 248 and 280),
distinguished by the weakness of their nitrogen spectra and by CIV
λ4658 emission. We propose that these stars have relatively
unprocessed CNO abundances compared to morphologically normal O-type
stars, indicative of an earlier evolutionary phase. From analysis of
observations obtained on two consecutive nights, we present
radial-velocity estimates for 233 stars, finding one apparent
single-lined binary and nine (>3σ) outliers compared to the
systemic velocity; the latter objects could be runaway stars or
large-amplitude binary systems and further spectroscopy is required to
investigate their nature.
Description:
This catalogue comprises ascii versions of the optical spectra of 263
massive stars in the Large Magellanic Cloud, obtained with the AAOmega
spectrograph on the Anglo Australian Telescope. Spectra from the first
night (2006 Feb 22) were obtained with a 1700B grating at two
wavelength settings. The spectra published here were obtained by
median combining the two exposures at both settings, and then median
combining them in the overlap region (spanning ∼4375-4400Å).
Spectra from the second night (2006 Feb 23) were obtained with a 1500V
grating at one central wavelength setting (4375Å). The spectra
The published spectra have been normalised/rectified using an
automated script, which uses pre-defined regions (selected to avoid
known absorption lines in early-type stars) to create a polynomial fit
to the notional continuum in each spectrum. The published spectra have
been divided by those fits to rectify them to unity. As such, we
caution the user that quantitative analysis of these data would
benefit from tailored rectification of the spectra. In particular, at
the ends of the spectral range, and across broad emission features
(such as that around HeII 4686 in luminous O-type supergiants). Also
note that there were a number of 'hot' columns in the AAOmega CCDs,
leading to small breaks (at multiple wavelengths) in the large
majority of the spectra.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 121 263 Observational parameters of target stars
table3.dat 52 264 MCPS photometry of target stars
(Zaritsky et al., 2004, Cat. J/AJ/128/1606)
table4.dat 138 58 Comparison of AAOmega classifications with
those available in the literature
sp1/* . 263 Combined 4375 spectra of each star
sp2/* . 263 Combined 4100+4700 spectra of each star
--------------------------------------------------------------------------------
See also:
J/AJ/128/1606 : Magellanic Clouds Photometric Survey: the LMC (Zaritsky+, 2004)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I03 --- AAO AAOmega star number
5- 6 I2 h RAh Right Ascension (J2000)
8- 9 I2 min RAm Right Ascension (J2000)
11- 15 F5.2 s RAs Right Ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 51 A23 --- SpType MK spectral classification
52- 56 F5.1 km/s RV1 ? Primary velocity
58- 61 F4.1 km/s e_RV1 ? rms uncertainty on RV1
63 I1 --- o_RV1 ? Number of measurements for RV1
65- 69 F5.1 km/s RV2 ? Secondary velocity
71- 74 F4.1 km/s e_RV2 ? rms uncertainty on RV2
76 I1 --- o_RV2 ? Number of measurements for RV2
78- 90 A13 --- Bin Binary status
92-121 A30 --- ONames Other name(s) (1)
--------------------------------------------------------------------------------
Note (1): Cross-references in final column are from:
Sanduleak (1969AJ.....74..877S 1969AJ.....74..877S, Sk)
Brunet et al. (1975A&AS...21..109B 1975A&AS...21..109B, BI)
Stock et al. (1976, Cat. J/A+AS/24/35, SOI)
Schild & Testor (1992A&AS...92..729S 1992A&AS...92..729S, ST92[1-4]-NN)
Parker (1993AJ....106..560P 1993AJ....106..560P, P93)
Testor & Niemela (1998A&AS..130..527T 1998A&AS..130..527T, ST92 5-NN)
Farina et al. (2009, Cat. J/AJ/138/510, F09)
Evans et al. (2011, Cat. J/A+A/530/A108, VFTS)
For all but the last two of these references we have employed Brian Skiff's
updated astrometry for cross-identifications
(see: ftp://ftp.lo well.edu/pub/bas/starcats/).
We also include matches to stars in LH 64, LH 81, LH 85, and LH 89
(Lucke & Hodge, 1970AJ.....75..171L 1970AJ.....75..171L) from Massey et al. (2000,
Cat. J/AJ/119/2214), in which we include their identifications for
sources from Westerlund (1961AJ.....66U..57W 1961AJ.....66U..57W) where relevant.
Sources of adopted classifications:
040: Walborn et al. (2004ApJ...608.1028W 2004ApJ...608.1028W)
254: Evans et al. (2010ApJ...715L..74E 2010ApJ...715L..74E)
276: Walborn et al. (2014, Cat. J/A+A/564/A40)
142, 187, 320, 333, 368 & 380: Walborn et al. (2010AJ....139.1283W 2010AJ....139.1283W)
Other relevant comments:
015: Sk-68 91a isa pair of stars separated by ∼4.5". The AA Omega
spectrum is of the southern star.
283: Possible contribution from VFTS 172 at 1.85"
296: MCPS position is offset, 0.66" SE of P93-304/VFTS 389; likely
contribution to observed spectrum as well from
P93-294/VFTS 386 (∼1.4" NW).
374: A preliminary classification of B1 III was given by
Muraveva et al. (2014MNRAS.443..432M 2014MNRAS.443..432M, identified aslm0031122987)
-------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I03 --- AAO AAOmega star number
5- 10 F6.3 mag Umag Johnson U magnitude
12- 17 F6.3 mag Bmag Johnson B magnitude
19- 24 F6.3 mag Vmag Johnson V magnitude
26- 31 F6.3 mag Icmag Cousins I magnitude
33- 38 F6.3 mag U-B Johnson U-B colour index
40- 45 F6.3 mag B-B Johnson B-V colour index
47- 52 F6.3 mag V-Ic Johnson-Cousins V-I colour index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I03 --- AAO AAOmega star number
5- 34 A30 --- AName Alias name
36- 58 A23 --- SpType AAOmega MK spectral classification
61-139 A79 --- SpTypeP Published MK spectral classification(s) (1)
--------------------------------------------------------------------------------
Note (1): Sources of classifications as follows:
SOI = Stock et al., Cat. J/A+AS/24/35
M85 = Melnick, 1985A&A...153..235M 1985A&A...153..235M
C86 = Conti et al., 1986AJ.....92...48C 1986AJ.....92...48C
F88 = Fitzpatrick, 1988ApJ...335..703F 1988ApJ...335..703F
F91 = Fitzpatrick, 1991PASP..103.1123F 1991PASP..103.1123F
M95 = Massey et al., 1995ApJ...438..188M 1995ApJ...438..188M
O96b = Oey, 1996ApJ...465..231O 1996ApJ...465..231O
WB97 = Walborn & Blades, 1997ApJS..112..457W 1997ApJS..112..457W
TN98 = Testor & Niemela, 1998A&AS..130..527T 1998A&AS..130..527T
M00 = Massey et al., 2000, Cat. J/AJ/119/2214
J01 = Jaxon et al., 2001PASP..113.1130J 2001PASP..113.1130J
W02 = Walborn et al., 2002AJ....123.2754W 2002AJ....123.2754W
W02b = Walborn et al., 2002AJ....124.1601W 2002AJ....124.1601W
W04 = Walborn et al., 2004ApJ...608.1028W 2004ApJ...608.1028W
M05 = Massey et al., 2005ApJ...627..477M 2005ApJ...627..477M
F09 = Farina et al., 2009, Cat. J/AJ/138/510
E10 = Evans et al., 2010ApJ...715L..74E 2010ApJ...715L..74E
W10 = Walborn et al., 2010AJ....139.1283W 2010AJ....139.1283W
M12 = Massey et al., 2012, J/ApJ/748/96
M14 = Muraveva et al. 2014MNRAS.443..432M 2014MNRAS.443..432M, which were earlier
classifications of the AAOmega spectra by CJE)
W14 = Walborn et al., 2014, Cat. J/A+A/564/A40
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sp1/* sp2/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 15 E13.8 0.1nm lambda Wavelength for each pixel (Angstrom)
17- 30 E14.7 --- I Normalised intensity
--------------------------------------------------------------------------------
Acknowledgements:
Chris Evans, chris.evans(at)stfc.ac.uk
(End) Chris Evans [UK Astron. Tech. Centre], Patricia Vannier [CDS] 31-Aug-2015