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SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way

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SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way. / Towner, Allison P. M.; Brogan, Crystal L.; Hunter, Todd R.; Cyganowski, Claudia J.; Friesen, Rachel K.

In: Astrophysical Journal, Vol. 875, No. 2, 135, 04.2019.

Research output: Contribution to journalArticle

Harvard

Towner, APM, Brogan, CL, Hunter, TR, Cyganowski, CJ & Friesen, RK 2019, 'SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way', Astrophysical Journal, vol. 875, no. 2, 135. https://doi.org/10.3847/1538-4357/ab1140

APA

Towner, A. P. M., Brogan, C. L., Hunter, T. R., Cyganowski, C. J., & Friesen, R. K. (2019). SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way. Astrophysical Journal, 875(2), [135]. https://doi.org/10.3847/1538-4357/ab1140

Vancouver

Towner APM, Brogan CL, Hunter TR, Cyganowski CJ, Friesen RK. SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way. Astrophysical Journal. 2019 Apr;875(2). 135. https://doi.org/10.3847/1538-4357/ab1140

Author

Towner, Allison P. M. ; Brogan, Crystal L. ; Hunter, Todd R. ; Cyganowski, Claudia J. ; Friesen, Rachel K. / SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way. In: Astrophysical Journal. 2019 ; Vol. 875, No. 2.

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@article{ae988cdd306c40968d15f71eef4e0874,
title = "SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way",
abstract = "Massive young stellar objects are known to undergo an evolutionary phase in which high mass accretion rates drive strong outflows. A class of objects believed to trace this phase accurately is the Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) Extended Green Object (EGO) sample, so named for the presence of extended 4.5μm emission on size scales of∼0.1pc in Spitzer images. We have been conducting a multi-wavelength examination of a sample of 12 EGOs with distances of 1-5 kpc. In this paper, we present mid-infrared images and photometry of these EGOs obtained with the Stratospheric Observatory for Infrared Astronomy and subsequently construct spectral energy distributions (SEDs) for these sources from the near-infrared to sub-millimeter regimes using additional archival data. We compare the results from graybody models and several publicly-available software packages which produce model SEDs in the context of a single massive protostar. The models yield typical R⋆ ∼10 R⊙, T⋆ ∼103-104 K, and L⋆ ∼1−40 × 103 L⊙; the median L/M for our sample is 24.7 L⊙/M⊙. Model results rarely converge for R⋆  and T⋆, but do for L⋆, which we take to be an indication of the multiplicity and inherently clustered nature of these sources even though, typically, only a single source dominates in the mid-infrared. The median L/M value for the sample suggests that these objects may be in a transitional stage between the commonly described “IR-quiet” and “IR-bright” stages of MYSO evolution. The median Tdust for the sample is less conclusive, but suggests that these objects are either in this transitional stage or occupy the cooler (and presumably younger) part of the IR-bright stage.",
keywords = "Infrared: general, Radiative transfer, Stars: formation, Stars: massive, Stars: protostars, Techniques: photometric",
author = "Towner, {Allison P. M.} and Brogan, {Crystal L.} and Hunter, {Todd R.} and Cyganowski, {Claudia J.} and Friesen, {Rachel K.}",
note = "Funding: UK STFC grant number ST/M001296/1 (CJC).",
year = "2019",
month = "4",
doi = "10.3847/1538-4357/ab1140",
language = "English",
volume = "875",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "American Astronomical Society",
number = "2",

}

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TY - JOUR

T1 - SOFIA FORCAST photometry of 12 Extended Green Objects in the Milky Way

AU - Towner, Allison P. M.

AU - Brogan, Crystal L.

AU - Hunter, Todd R.

AU - Cyganowski, Claudia J.

AU - Friesen, Rachel K.

N1 - Funding: UK STFC grant number ST/M001296/1 (CJC).

PY - 2019/4

Y1 - 2019/4

N2 - Massive young stellar objects are known to undergo an evolutionary phase in which high mass accretion rates drive strong outflows. A class of objects believed to trace this phase accurately is the Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) Extended Green Object (EGO) sample, so named for the presence of extended 4.5μm emission on size scales of∼0.1pc in Spitzer images. We have been conducting a multi-wavelength examination of a sample of 12 EGOs with distances of 1-5 kpc. In this paper, we present mid-infrared images and photometry of these EGOs obtained with the Stratospheric Observatory for Infrared Astronomy and subsequently construct spectral energy distributions (SEDs) for these sources from the near-infrared to sub-millimeter regimes using additional archival data. We compare the results from graybody models and several publicly-available software packages which produce model SEDs in the context of a single massive protostar. The models yield typical R⋆ ∼10 R⊙, T⋆ ∼103-104 K, and L⋆ ∼1−40 × 103 L⊙; the median L/M for our sample is 24.7 L⊙/M⊙. Model results rarely converge for R⋆  and T⋆, but do for L⋆, which we take to be an indication of the multiplicity and inherently clustered nature of these sources even though, typically, only a single source dominates in the mid-infrared. The median L/M value for the sample suggests that these objects may be in a transitional stage between the commonly described “IR-quiet” and “IR-bright” stages of MYSO evolution. The median Tdust for the sample is less conclusive, but suggests that these objects are either in this transitional stage or occupy the cooler (and presumably younger) part of the IR-bright stage.

AB - Massive young stellar objects are known to undergo an evolutionary phase in which high mass accretion rates drive strong outflows. A class of objects believed to trace this phase accurately is the Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) Extended Green Object (EGO) sample, so named for the presence of extended 4.5μm emission on size scales of∼0.1pc in Spitzer images. We have been conducting a multi-wavelength examination of a sample of 12 EGOs with distances of 1-5 kpc. In this paper, we present mid-infrared images and photometry of these EGOs obtained with the Stratospheric Observatory for Infrared Astronomy and subsequently construct spectral energy distributions (SEDs) for these sources from the near-infrared to sub-millimeter regimes using additional archival data. We compare the results from graybody models and several publicly-available software packages which produce model SEDs in the context of a single massive protostar. The models yield typical R⋆ ∼10 R⊙, T⋆ ∼103-104 K, and L⋆ ∼1−40 × 103 L⊙; the median L/M for our sample is 24.7 L⊙/M⊙. Model results rarely converge for R⋆  and T⋆, but do for L⋆, which we take to be an indication of the multiplicity and inherently clustered nature of these sources even though, typically, only a single source dominates in the mid-infrared. The median L/M value for the sample suggests that these objects may be in a transitional stage between the commonly described “IR-quiet” and “IR-bright” stages of MYSO evolution. The median Tdust for the sample is less conclusive, but suggests that these objects are either in this transitional stage or occupy the cooler (and presumably younger) part of the IR-bright stage.

KW - Infrared: general

KW - Radiative transfer

KW - Stars: formation

KW - Stars: massive

KW - Stars: protostars

KW - Techniques: photometric

U2 - 10.3847/1538-4357/ab1140

DO - 10.3847/1538-4357/ab1140

M3 - Article

VL - 875

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 135

ER -

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