J/ApJ/834/122 Massive star formation in the LMC. I. N159 & N160 (Gordon+, 2017)
Massive star formation in the LMC.
I. N159 and N160 complexes.
Gordon M.S., Jones T.J., Gehrz R.D., Helton L.A.
<Astrophys. J., 834, 122-122 (2017)>
=2017ApJ...834..122G 2017ApJ...834..122G (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Photometry, infrared ; H II regions ; YSOs
Keywords: H II regions; Magellanic Clouds; stars: formation
Abstract:
We present images and spectral energy distributions (SEDs) of massive
young stellar objects (YSOs) in three star-forming H II regions of the
Large Magellanic Cloud: N159A, N159 Papillon, and N160. We use
photometry from SOFIA/FORCAST at 25.3-37.1µm to constrain model
fits to the SEDs and determine luminosities, ages, and dust content of
the embedded YSOs and their local environments. By placing these
sources on mid-infrared color-magnitude and color-color diagrams, we
analyze their dust properties and consider their evolutionary status.
Since each object in the FORCAST images has an obvious bright
near-infrared counterpart in Spitzer Space Telescope images, we do not
find any evidence for new, very cool, previously undiscovered Class 0
YSOs. Additionally, based on its mid-infrared colors and model
parameters, N159A is younger than N160 and the Papillon. The nature of
the first extragalactic protostars in N159, P1, and P2, is also
discussed.
Description:
The N159A, N159 Papillon, and N160 fields were observed with SOFIA
during missions OC3-D and F on 2015 June 19 and July 6, using the
Faint Object Infrared Camera for the SOFIA Telescope (FORCAST), which
performs both imaging and spectroscopy from 5 to 40um. We observed
each of the three fields in three bands with effective wavelengths of
25.3, 31.5, and 37.1um in 2015 Jun 19 and in 2015 Jul 06 for N160.
Observations were also made in 2004 December using all four bands of
the Infrared Array Camera (IRAC) on the Spitzer Space Telescope as
part of a Guaranteed Time Observing Program (Program ID 124).
We also include in our analysis the publicly available 100um
observations from the Herschel Space Observatory with the PACS
instrument. Observations were taken on 2010 October 05 as part of the
Herschel Inventory of the Agents of Galaxy Evolution (HERITAGE) in the
Magellanic Clouds open time key program (Meixner+ 2013, J/AJ/146/62;
Seale+ 2014, J/AJ/148/124, Obs ID 1342202224).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 189 14 Photometry of IR sources
table3.dat 52 14 Derived YSO model parameters
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/381/941 : HST photometry of stars in N160A (Heydari-Malayeri+, 2002)
J/A+A/422/129 : JHKs photometry in N159 (LMC) (Meynadier+, 2004)
J/A+A/453/517 : JKs photometry of N159A (Testor+, 2006)
J/AJ/135/2323 : Hα stars and HH objects near BRCs (Ikeda+, 2008)
J/AJ/138/510 : Spectral classification of N159/N160 stars (Farina+, 2009)
J/ApJ/699/150 : Spectral classifications of Massive YSOs in LMC (Seale+, 2009)
J/ApJ/707/1417 : HST view of YSOs in the LMC (Vaidya+, 2009)
J/ApJS/184/172 : High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)
J/ApJ/715/310 : Early stages of star formation in IRDCs (Rathborne+, 2010)
J/A+A/537/A146 : Stellar models with rotation, Z=0.014 (Ekstrom+, 2012)
J/A+A/542/A66 : YSOs in 9 LMC star forming regions (Carlson+, 2012)
J/ApJ/779/79 : Galactic CHaMP. II. Dense gas clumps. (Ma+, 2013)
J/AJ/146/62 : HERschel HERITAGE in Magellanic Clouds (Meixner+, 2013)
J/AJ/148/124 : Herschel key program Heritage (Seale+, 2014)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Reg Massive star formation region identifier
8 A1 --- --- [_]
9 A1 --- YSO YSO candidate identifier
11- 26 A16 --- 2MASS 2MASS identifier
28- 55 A28 --- OName Other identifier (1)
57- 58 I2 h RAh Hour of Right Ascension (J2000)
60- 61 I2 min RAm Minute of Right Ascension (J2000)
63- 67 F5.2 s RAs Second of Right Ascension (J2000)
69- 69 A1 --- DE- Sign of the Declination (J2000)
70- 71 I2 deg DEd Degree of Declination (J2000)
73- 74 I2 arcmin DEm Arcminute of Declination (J2000)
76- 79 F4.1 arcsec DEs Arcsecond of Declination (J2000)
81- 85 F5.2 mJy FJ ? 2MASS J band flux density (2)
87- 91 F5.2 mJy FH ? 2MASS H band flux density (2)
93- 97 F5.2 mJy FKs ? 2MASS KS band flux density (2)
99-103 F5.2 mJy F3.6 [5/60] Spitzer/IRAC 3.6um band flux density
105-107 F3.1 mJy e_F3.6 [0.3/3] Uncertainty in F3.6
109-114 F6.2 mJy F4.5 [3/126] Spitzer/IRAC 4.5um band flux density
116-118 F3.1 mJy e_F4.5 [0.2/7] Uncertainty in F4.5
120-125 F6.2 mJy F5.8 [25/285] Spitzer/IRAC 5.8um band flux density
127-130 F4.1 mJy e_F5.8 [1/15] Uncertainty in F5.8
132-137 F6.2 mJy F8.0 [61/901] Spitzer/IRAC 8.0um band flux density
139-142 F4.1 mJy e_F8.0 [3/45] Uncertainty in F8.0
144-148 F5.2 Jy F25.3 [0.2/39] SOFIA/FORCAST 25.3um band flux density
150-153 F4.2 Jy e_F25.3 [0.9/5] Uncertainty in F25.3
155-159 F5.2 Jy F31.5 ? SOFIA/FORCAST 31.5 micron band flux density
161-165 F5.2 Jy e_F31.5 ? Uncertainty in F31.5
167-171 F5.2 Jy F37.1 ? SOFIA/FORCAST 37.1 micron band flux density
173-176 F4.2 Jy e_F37.1 ? Uncertainty in F37.1
178-183 F6.2 Jy F100 ? Herschel/PACS 100 micron band flux density
185-189 F5.2 Jy e_F100 ? Uncertainty in F
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Note (1): Sources labeled C2-C5 in N159A are identified as compact clusters
in Bernard+ (2016A&A...592A..77B 2016A&A...592A..77B).
N159A A and N160 A are in Seale+ (2014, J/AJ/148/124;
see Section 2.3; in Simbad).
N160 sources are matched to sources in
Heydari-Malayeri+ (2002, J/A+A/381/941; <[HCD2002] NNN> in Simbad).
Note (2): Jones+ (2005ApJ...620..731J 2005ApJ...620..731J) provides JHKs photometry from the
Two Micron All Sky Survey (2MASS) for several of the IRAC sources in
N159. We adopt those values here.
See section 2.4 for further explanations.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Reg Massive star formation region identifier
9- 11 F3.1 mag Av [4.4/7.4] Mean foreground Av of the region (3)
13- 15 E3.1 yr Age Mean age of the region
17 A1 --- YSO YSO candidate identifier
19- 22 F4.1 --- tauKs [5.6/84.8] Optical depth at 2.2um (4)
24- 28 E5.2 Lsun Lum [11000/390000] Luminosity
30- 34 E5.2 K Temp [28000/46000] Temperature
36- 38 I3 K Tdust [57/123]? Dust temperature (5)
40- 45 E6.2 Msun Mdisk [0.0001/0.6]? Disk mass
47- 52 E6.2 Msun/yr dM/dt ? Disk accretion
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Note (3): Extinction in the foreground of the models averaged by cluster.
Note (4): Optical depth at 2.2um inside the model down to the stellar surface,
assuming Indebetouw+ (2005ApJ...619..931I 2005ApJ...619..931I) extinction.
Note (5): Dust temperatures calculated from fitting modified gray bodies
(β=1.8 for N159, 2.0 for N160) to fluxes for λ>20um
(see Figure 6 and Section 3).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Jul-2017