J/ApJ/843/33 SOFIA Massive (SOMA) Star Formation Survey. I. (De Buizer+, 2017)
The SOFIA Massive (SOMA) Star Formation Survey.
I. Overview and first results.
De Buizer J.M., Liu M., Tan J.C., Zhang Y., Beltran M.T., Shuping R.,
Staff J.E., Tanaka K.E.I., Whitney B.
<Astrophys. J., 843, 33 (2017)>
=2017ApJ...843...33D 2017ApJ...843...33D
ADC_Keywords: Stars, distances ; Stars, masses ; YSOs ; Models ;
Interstellar medium ; Spectra, infrared
Keywords: dust; infrared: stars; ISM: jets and outflows; stars: early-type;
stars: formation; stars: winds, outflows
Abstract:
We present an overview and first results of the Stratospheric
Observatory For Infrared Astronomy Massive (SOMA) Star Formation
Survey, which is using the FORCAST instrument to image massive
protostars from ∼10 to 40µm. These wavelengths trace thermal
emission from warm dust, which in Core Accretion models mainly emerges
from the inner regions of protostellar outflow cavities. Dust in dense
core envelopes also imprints characteristic extinction patterns at
these wavelengths, causing intensity peaks to shift along the outflow
axis and profiles to become more symmetric at longer wavelengths. We
present observational results for the first eight protostars in the
survey, i.e., multiwavelength images, including some ancillary
ground-based mid- infrared (MIR) observations and archival Spitzer and
Herschel data. These images generally show extended MIR/FIR emission
along directions consistent with those of known outflows and with
shorter wavelength peak flux positions displaced from the protostar
along the blueshifted, near-facing sides, thus confirming qualitative
predictions of Core Accretion models. We then compile spectral energy
distributions and use these to derive protostellar properties by
fitting theoretical radiative transfer models. Zhang and Tan models,
based on the Turbulent Core Model of McKee and Tan, imply the sources
have protostellar masses m*∼10-50M☉ accreting at
∼10-4-10-3M☉/yr inside cores of initial masses
Mc∼30-500M☉ embedded in clumps with mass surface densities
Σcl∼0.1-3g/cm2. Fitting the Robitaille et al. models
typically leads to slightly higher protostellar masses, but with disk
accretion rates ∼100x smaller. We discuss reasons for these
differences and overall implications of these first survey results for
massive star formation theories.
Description:
The following eight sources, AFGL 4029, AFGL 437, IRAS 07299-1651,
G35.20-0.74, G45.45+0.05, IRAS 20126+4104, Cepheus A, and
NGC 7538 IRS9, were observed by SOFIA with the FORCAST instrument (see
Table 1). Data were taken on multiple flights spanning the Early
Science period, Cycle 1, and Cycle 2 SOFIA observing cycles (spanning
2011 May to 2014 June).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 8 SOFIA FORCAST observations: observation dates and
exposure times
table2.dat 310 22 Integrated flux densities
table3.dat 140 40 Parameters of the five best fitted models
of Zhang & Tan (section 3.2.1) and
Robitaille+ (2007ApJS..169..328R 2007ApJS..169..328R ; see section 3.2.2)
fits/* . 46 Individual FITS images for the 8 sources in at least
five of the following bands: Heschel 70um,
Spitzer/IRAC 8um, SOFIA 7um, 19um, 31um, 37um, 11um,
25um
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See also:
J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
J/MNRAS/301/640 : Ultracompact H II regions studies. II. (Walsh+, 1998)
J/AJ/130/586 : Compact radio sources in the galactic plane (White+, 2005)
J/AJ/136/2391 : GLIMPSE Extended Green Objects catalog (Cyganowski+, 2008)
J/other/RAA/10.67 : CH3OH maser sources (Liu+, 2010)
J/MNRAS/418/2121 : CO 3-2 observations of outflows in W5 (Ginsburg+, 2011)
J/A+A/558/A81 : NGC 7538 IRS1 maps in CH3OH, HCN and HCO+ (Beuther+, 2013)
J/A+A/558/A24 : The VLTI/MIDI survey of Massive YSOs (Boley+, 2013)
J/A+A/559/L2 : H and Ks maps around G045.47+0.05 (Paron+, 2013)
J/A+A/569/A11 : G35.20-0.74N continuum & line data cubes (Sanchez-Monge+,
2014)
J/A+A/593/A49 : G35.20-0.74N VLA continuum images (Beltran+, 2016)
J/ApJS/227/25 : 6 & 1.3cm VLA obs. toward 58 high-mass SFRs (Rosero+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- ID Identifier
16- 17 I2 h RAh Hour of Right Ascension (J2000)
19- 20 I2 min RAm Minute of Right Ascension (J2000)
22- 26 F5.2 s RAs Second of Right Ascension (J2000)
28 A1 --- DE- Sign of the Declination (J2000)
29- 30 I2 deg DEd Degree of Declination (J2000)
32- 33 I2 arcmin DEm Arcminute of Declination (J2000)
35- 39 F5.2 arcsec DEs Arcsecond of Declination (J2000)
41- 44 F4.2 kpc Dist Distance
46- 55 A10 "Y-M-D" Obs Observation date
57- 59 I3 s Exp7.7 ? Exposure time for 7.7 micron observation
61- 63 I3 s Exp11.1 ? Exposure time for 11.1 micron observation
65- 68 I4 s Exp19.7 ? Exposure time for 19.7 micron observation
70- 73 I4 s Exp25.3 ? Exposure time for 25.3 micron observation
75- 78 I4 s Exp31.5 Exposure time for 31.5 micron observation
80- 83 I4 s Exp37.1 Exposure time for 37.1 micron observation
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Inst Facility identifier
16- 20 F5.1 um lambda [2.1/500] Wavelength of the observation
22- 27 F6.2 Jy F1fs ?=-9.9 Flux density of AFGL 4029 (1)
29- 34 F6.2 Jy F1f ?=-9.9 Flux density of AFGL 4029 (2)
36- 41 F6.2 Jy F1vs ?=-9.9 Flux density of AFGL 4029 (3)
43- 48 F6.2 Jy F1v ?=-9.9 Flux density of AFGL 4029 (4)
50- 53 F4.1 arcsec R1 ?=-9.9 Aperture radius for AFGL 4029
55- 61 F7.2 Jy F2fs ?=-9.9 Flux density of AFGL 437 (1)
63- 69 F7.2 Jy F2f ?=-9.9 Flux density of AFGL 437 (2)
71- 77 F7.2 Jy F2vs ?=-9.9 Flux density of AFGL 437 (3)
79- 85 F7.2 Jy F2v ?=-9.9 Flux density of AFGL 437 (4)
87- 90 F4.1 arcsec R2 [11/32]?=-9.9 Aperture radius for AFGL 437
92- 97 F6.2 Jy F3fs ?=-9.9 Flux density of IRAS 07299 (1)
99-104 F6.2 Jy F3f ?=-9.9 Flux density of IRAS 07299 (2)
106-111 F6.2 Jy F3vs ?=-9.9 Flux density of IRAS 07299 (3)
113-118 F6.2 Jy F3v ?=-9.9 Flux density of IRAS 07299 (4)
120-123 F4.1 arcsec R3 ?=-9.9 Aperture radius for IRAS 07299
125-131 F7.2 Jy F4fs ?=-9.9 Flux density of G35.20-0.74 (1)
133-139 F7.2 Jy F4f ?=-9.9 Flux density of G35.20-0.74 (2)
141-147 F7.2 Jy F4vs ?=-9.9 Flux density of G35.20-0.74 (3)
149-155 F7.2 Jy F4v ?=-9.9 Flux density of G35.20-0.74 (4)
157-160 F4.1 arcsec R4 ?=-9.9 Aperture radius for G35.20-0.74
162-167 F6.2 Jy F5fs ?=-9.9 Flux density of G45.47+0.05 (1)
169-175 F7.2 Jy F5f ?=-9.9 Flux density of G45.47+0.05 (2)
177-182 F6.2 Jy F5vs ?=-9.9 Flux density of G45.47+0.05 (3)
184-190 F7.2 Jy F5v ?=-9.9 Flux density of G45.47+0.05 (4)
192-195 F4.1 arcsec R5 ?=-9.9 Aperture radius for G45.47+0.05
197-203 F7.2 Jy F6fs ?=-9.9 Flux density of IRAS 20126 (1)
205-211 F7.2 Jy F6f ?=-9.9 Flux density of IRAS 20126 (2)
213-219 F7.2 Jy F6vs ?=-9.9 Flux density of IRAS 20126 (3)
221-227 F7.2 Jy F6v ?=-9.9 Flux density of IRAS 20126 (4)
229-232 F4.1 arcsec R6 ?=-9.9 Aperture radius for IRAS 20126
234-241 F8.2 Jy F7fs ?=-9.9 Flux density of Cep A (1)
243-250 F8.2 Jy F7f ?=-9.9 Flux density of Cep A (2)
252-259 F8.2 Jy F7vs ?=-9.9 Flux density of Cep A (3)
261-268 F8.2 Jy F7v ?=-9.9 Flux density of Cep A (4)
270-273 F4.1 arcsec R7 [15/48]?=-9.9 Aperture radius for Cep A
275-281 F7.2 Jy F8fs ?=-9.9 Flux density of NGC7538 IRS9 (1)
283-289 F7.2 Jy F8f ?=-9.9 Flux density of NGC7538 IRS9 (2)
291-297 F7.2 Jy F8vs ?=-9.9 Flux density of NGC7538 IRS9 (3)
299-305 F7.2 Jy F8v ?=-9.9 Flux density of NGC7538 IRS9 (4)
307-310 F4.1 arcsec R8 ?=-9.9 Aperture radius for NGC7538 IRS9
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Note (1): Flux density derived with a fixed aperture size of the 70 micron data
and with background subtraction.
Note (2): Flux density derived with a fixed aperture size of the 70 micron data
and without background subtraction.
Note (3): Flux density derived with wavelength-dependent variable aperture
sizes and with background subtraction.
Note (4): Flux density derived with wavelength-dependent variable aperture
sizes and without background subtraction.
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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- 14 A14 --- ID Identifier
16- 19 F4.2 kpc Dist [0.7/8.4] Distance
21- 24 F4.1 arcsec Rap [7.7/48] Aperture radius
26- 29 F4.2 --- ZTchi2 Zhang & Tan χ2 of model fit
31- 33 I3 Msun ZTMc [30/480] Zhang & Tan core mass
35- 37 F3.1 g/cm2 ZTSigma Zhang & Tan clump mass surface density
39- 42 F4.2 pc ZTPRc [0.03/0.6] Zhang & Tan physical clump radius
44- 46 I3 arcsec ZTARc Zhang & Tan angular clump radius
48- 49 I2 Msun ZTM* [8/48] Zhang & Tan protostar mass
51- 52 I2 deg ZTInc Zhang & Tan inclination
54- 58 F5.1 mag ZTAv [0/100] Zhang & Tan V band extinction
60- 62 I3 Msun ZTMenv Zhang & Tan envelope mass
64- 65 I2 deg ZTtheta Zhang & Tan opening angle
67- 73 E7.1 Msun/yr ZTMdot Zhang & Tan disk accretion rate
75- 81 E7.1 Lsun ZTLbol [10000/510000] Zhang & Tan bolometric
luminosity
83- 86 F4.2 --- Robchi2 Robitaille et al. χ2 of model fit
88- 89 I2 Msun RobM* [11/34] Robitaille et al. protostar mass
91- 92 I2 deg RobInc Robitaille et al. inclination
94- 98 F5.1 mag RobAv [10/108] Robitaille et al. V band extinction
100-103 I4 Msun RobMenv Robitaille et al. envelope mass
105-108 F4.2 pc RobPRenv [0.1/0.5] Robitaille et al. physical
envelope radius
110-112 I3 arcsec RobARenv Robitaille et al. angular envelope radius
114-115 I2 deg Robtheta Robitaille et al. opening angle
117-123 E7.1 Msun/yr RobEMdot [0.0001/0.005] Robitaille et al. envelope
accretion rate
125-132 E8.1 Msun/yr RobDMdot ?=-1 Robitaille et al. disk accretion rate
134-140 E7.1 Lsun RobLbol [8700/170000] Robitaille et al. bolometric
luminosity
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Feb-2018