J/A+A/589/A16 Spectra of W49 massive young stars (Wu+, 2016)
The massive stellar population of W49: A spectroscopic survey.
Wu S.-W., Bik A., Bestenlehner J.M., Henning T., Pasquali A., Brandner W.,
Stolte A.
<Astron. Astrophys. 589, A16 (2016)>
=2016A&A...589A..16W 2016A&A...589A..16W (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Stars, OB ; YSOs ; Spectroscopy
Keywords: stars: formation - stars: massive - supergiants - infrared: stars -
techniques: spectroscopic -
open clusters and associations: individual: W49
Abstract:
Massive stars form on different scales ranging from large, dispersed
OB associations to compact, dense starburst clusters. The complex
structure of regions of massive star formation, and the involved short
timescales provide a challenge for our understanding of their birth
and early evolution. As one of the most massive and luminous star-
forming region in our Galaxy, W49 is the ideal place to study the
formation of the most massive stars.
By classifying the massive young stars deeply embedded into the
molecular cloud of W49, we aim to investigate and trace the star
formation history of this region.
We analyse near-infrared K-band spectroscopic observations of W49
from LBT/LUCI combined with JHK images obtained with NTT/SOFI and
LBT/LUCI. Based on JHK -band photometry and K-band spectroscopy the
massive stars are placed in a Hertzsprung Russell diagram. By
comparison with evolutionary models, their age and hence the star
formation history of W49 can be investigated.
Description:
Near-infrared observations have been carried out with LUCI mounted on
the Large Binocular Telescope (LBT), Mount Graham, Arizona. LUCI is a
near-infrared multi-mode instrument capable of Multi-Object
Spectroscopy (MOS), long-slit spectroscopy and imaging. The spectra of
the massive stars in W49 have been taken in MOS mode based on K-band
pre-image also obtained with LUCI. Additional archival data were used
to complement the LUCI data. Medium-resolution (R=10,000) K-band
spectra of five massive stars in W49 obtained with ISAAC mounted on
Antu (UT1) of ESO's Very Large Telescope (VLT), Paranal, Chile, and
J- and H -band images obtained with SOFI at the New Technology
Telescope (NTT), La Silla, Chile, were downloaded from the ESO
archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 193 22 Spectroscopically observed massive stars in W49
and informations of fits spectrum files
sp/* . 22 Individual fits spectrum files
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Sequential number
4- 20 A17 --- Name Source ID
21 A1 --- n_Name [y] Note on Name (1)
23- 24 I2 h RAh right ascension (J2000)
26- 27 I2 min RAm right ascension (J2000)
29- 32 F4.1 s RAs right ascension (J2000)
34 A1 --- DE- Declination sign (J2000)
35- 36 I2 deg DEd Declination (J2000)
38- 39 I2 arcmin DEm Declination (J2000)
41- 42 I2 arcsec DEs Declination (J2000)
44- 48 F5.2 mag Jmag ?=- J magnitude
50- 53 F4.2 mag e_Jmag ? rms uncertainty on Jmag
55- 59 F5.2 mag Hmag ?=- H magnitude
61- 64 F4.2 mag e_Hmag ? rms uncertainty on Hmag
66- 70 F5.2 mag Kmag K magnitude
72- 75 F4.2 mag e_Kmag rms uncertainty on Kmag
77- 89 A13 --- Class Classification
91-100 A10 "date" ObsDate1 Observation date of fits spectrum file
102-111 A10 "date" ObsDate2 Second observation date
112 A1 --- n_ObsDate2 [y] Note on ObsDate2 (1)
114-123 A10 "date" ObsDate3 Third observation date
124 A1 --- n_ObsDate3 [y] Note on ObsDate3 (1)
126-135 A10 "date" ObsDate4 Fourth observation date
136 A1 --- n_ObsDate4 [y] Note on ObsDate4 (1)
138-141 I4 --- Nx Number of pixels along X-axis of
fits spectrum file
143-149 F7.1 0.1nm blambda Lower value of spectral interval of
fits spectrum file
151-157 F7.1 0.1nm Blambda Upper value of spectral interval of
fits spectrum file
159-165 F7.5 0.1nm dlambda Spectral resolution of fits spectrum file
167-168 I2 Kibyte size Size of fits spectrum file
170-193 A24 --- FileName Name of fits spectrum file, in subdirectory sp
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Note (1): y indicates that stars also observed by ISAAC/VLT
(PI: N. Homeier, Program ID: 073.D-0837)
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Acknowledgements:
Shiwei Wu, shiwei(at)mpia.de
(End) Patricia Vannier [CDS] 18-Feb-2016