A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz

Colm P. Coughlan; Rachael Ainsworth; Jochen Eislöffel; Matthias Hoeft; Alexander Drabent; Anna M M Scaife; Tom P. Ray; Martin E. Bell; Jess W. Broderick; Stéphane Corbel; Jean Mathias Grießmeier; Alexander J. Van Der Horst; Joeri Van Leeuwen; Sera Markoff; Malgorzata Pietka; Adam J. Stewart; Ralph A M J Wijers; Philippe Zarka

doi:10.3847/1538-4357/834/2/206

A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz

Colm P. Coughlan, Rachael Ainsworth, Jochen Eislöffel, Matthias Hoeft, Alexander Drabent, Anna M M Scaife, Tom P. Ray, Martin E. Bell, Jess W. Broderick, Stéphane Corbel, Jean Mathias Grießmeier, Alexander J. Van Der Horst, Joeri Van Leeuwen, Sera Markoff, Malgorzata Pietka, Adam J. Stewart, Ralph A M J Wijers, Philippe Zarka

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Abstract

Radio observations of young stellar objects (YSOs) enable the study of ionized plasma outflows from young protostars via their free-free radiation. Previous studies of the low-mass young system T Tau have used radio observations to model the spectrum and estimate important physical properties of the associated ionized plasma (local electron density, ionized gas content, and emission measure). However, without an indication of the low-frequency turnover in the free-free spectrum, these properties remain difficult to constrain. This paper presents the detection of T Tau at 149 MHz with the Low Frequency Array (LOFAR)-the first time a YSO has been observed at such low frequencies. The recovered total flux indicates that the free-free spectrum may be turning over near 149 MHz. The spectral energy distribution is fitted and yields improved constraints on local electron density ((7.2 ± 2.1) × 10³ cm^-3), ionized gas mass ((1.0 ± 1.8) × 10^-6 M_sun), and emission measure ((1.67 ± 0.14) × 10⁵ pc cm^-6).

Original language	English
Article number	206
Journal	Astrophysical Journal
Volume	834
Issue number	2
DOIs	https://doi.org/10.3847/1538-4357/834/2/206
Publication status	Published - 10 Jan 2017

Keywords

radiation mechanisms: thermal
radio continuum: stars
stars: individual (T Tauri)
stars: pre-main sequence
stars: protostars

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Coughlan, C. P., Ainsworth, R., Eislöffel, J., Hoeft, M., Drabent, A., Scaife, A. M. M., Ray, T. P., Bell, M. E., Broderick, J. W., Corbel, S., Grießmeier, J. M., Van Der Horst, A. J., Van Leeuwen, J., Markoff, S., Pietka, M., Stewart, A. J., Wijers, R. A. M. J., & Zarka, P. (2017). A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz. Astrophysical Journal, 834(2), Article 206. https://doi.org/10.3847/1538-4357/834/2/206

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title = "A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz",

abstract = "Radio observations of young stellar objects (YSOs) enable the study of ionized plasma outflows from young protostars via their free-free radiation. Previous studies of the low-mass young system T Tau have used radio observations to model the spectrum and estimate important physical properties of the associated ionized plasma (local electron density, ionized gas content, and emission measure). However, without an indication of the low-frequency turnover in the free-free spectrum, these properties remain difficult to constrain. This paper presents the detection of T Tau at 149 MHz with the Low Frequency Array (LOFAR)-the first time a YSO has been observed at such low frequencies. The recovered total flux indicates that the free-free spectrum may be turning over near 149 MHz. The spectral energy distribution is fitted and yields improved constraints on local electron density ((7.2 ± 2.1) × 103 cm-3), ionized gas mass ((1.0 ± 1.8) × 10-6 M_sun), and emission measure ((1.67 ± 0.14) × 105 pc cm-6).",

keywords = "radiation mechanisms: thermal, radio continuum: stars, stars: individual (T Tauri), stars: pre-main sequence, stars: protostars",

author = "Coughlan, {Colm P.} and Rachael Ainsworth and Jochen Eisl{\"o}ffel and Matthias Hoeft and Alexander Drabent and Scaife, {Anna M M} and Ray, {Tom P.} and Bell, {Martin E.} and Broderick, {Jess W.} and St{\'e}phane Corbel and Grie{\ss}meier, {Jean Mathias} and {Van Der Horst}, {Alexander J.} and {Van Leeuwen}, Joeri and Sera Markoff and Malgorzata Pietka and Stewart, {Adam J.} and Wijers, {Ralph A M J} and Philippe Zarka",

year = "2017",

month = jan,

day = "10",

doi = "10.3847/1538-4357/834/2/206",

language = "English",

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journal = "Astrophysical Journal",

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Coughlan, CP, Ainsworth, R, Eislöffel, J, Hoeft, M, Drabent, A, Scaife, AMM, Ray, TP, Bell, ME, Broderick, JW, Corbel, S, Grießmeier, JM, Van Der Horst, AJ, Van Leeuwen, J, Markoff, S, Pietka, M, Stewart, AJ, Wijers, RAMJ & Zarka, P 2017, 'A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz', Astrophysical Journal, vol. 834, no. 2, 206. https://doi.org/10.3847/1538-4357/834/2/206

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T1 - A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz

AU - Coughlan, Colm P.

AU - Ainsworth, Rachael

AU - Eislöffel, Jochen

AU - Hoeft, Matthias

AU - Drabent, Alexander

AU - Scaife, Anna M M

AU - Ray, Tom P.

AU - Bell, Martin E.

AU - Broderick, Jess W.

AU - Corbel, Stéphane

AU - Grießmeier, Jean Mathias

AU - Van Der Horst, Alexander J.

AU - Van Leeuwen, Joeri

AU - Markoff, Sera

AU - Pietka, Malgorzata

AU - Stewart, Adam J.

AU - Wijers, Ralph A M J

AU - Zarka, Philippe

PY - 2017/1/10

Y1 - 2017/1/10

N2 - Radio observations of young stellar objects (YSOs) enable the study of ionized plasma outflows from young protostars via their free-free radiation. Previous studies of the low-mass young system T Tau have used radio observations to model the spectrum and estimate important physical properties of the associated ionized plasma (local electron density, ionized gas content, and emission measure). However, without an indication of the low-frequency turnover in the free-free spectrum, these properties remain difficult to constrain. This paper presents the detection of T Tau at 149 MHz with the Low Frequency Array (LOFAR)-the first time a YSO has been observed at such low frequencies. The recovered total flux indicates that the free-free spectrum may be turning over near 149 MHz. The spectral energy distribution is fitted and yields improved constraints on local electron density ((7.2 ± 2.1) × 103 cm-3), ionized gas mass ((1.0 ± 1.8) × 10-6 M_sun), and emission measure ((1.67 ± 0.14) × 105 pc cm-6).

AB - Radio observations of young stellar objects (YSOs) enable the study of ionized plasma outflows from young protostars via their free-free radiation. Previous studies of the low-mass young system T Tau have used radio observations to model the spectrum and estimate important physical properties of the associated ionized plasma (local electron density, ionized gas content, and emission measure). However, without an indication of the low-frequency turnover in the free-free spectrum, these properties remain difficult to constrain. This paper presents the detection of T Tau at 149 MHz with the Low Frequency Array (LOFAR)-the first time a YSO has been observed at such low frequencies. The recovered total flux indicates that the free-free spectrum may be turning over near 149 MHz. The spectral energy distribution is fitted and yields improved constraints on local electron density ((7.2 ± 2.1) × 103 cm-3), ionized gas mass ((1.0 ± 1.8) × 10-6 M_sun), and emission measure ((1.67 ± 0.14) × 105 pc cm-6).

KW - radiation mechanisms: thermal

KW - radio continuum: stars

KW - stars: individual (T Tauri)

KW - stars: pre-main sequence

KW - stars: protostars

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U2 - 10.3847/1538-4357/834/2/206

DO - 10.3847/1538-4357/834/2/206

M3 - Article

AN - SCOPUS:85010031064

SN - 0004-637X

VL - 834

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 206

ER -

A LOFAR DETECTION of the LOW-MASS YOUNG STAR T TAU at 149 MHz

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