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 (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:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 189 14 Photometry of IR sources table3.dat 52 14 Derived YSO model parameters
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
Bytes Format Units Label Explanations
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 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
Note (1): Sources labeled C2-C5 in N159A are identified as compact clusters in Bernard+ (2016A&A...592A..77B). N159A A and N160 A are in Seale+ (2014, J/AJ/148/124; see Section 2.3; <HSOBMHERICC JDDD.dddd+DD.dddd> 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) 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.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
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
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) 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).
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Jul-2017
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