Radio continuum emission from knots in the DG Tauri jet

Rodrı́guez, Luis F.; González, R. F.; Raga, A. C.; Cantó, J.; Riera, A.; Loinard, Laurent; Dzib, S. A.; Zapata, Luis A.

doi:10.1051/0004-6361/201117991

Cited by 39 publications

(71 citation statements)

References 30 publications

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“…′′ 27 yr −1 similar to those of other optical and infrared knots (Güdel et al 2008(Güdel et al , 2012Rodríguez et al 2012). Tracing this proper motion back in time, the X-ray knot would have appeared in the ∼ 2.…”

Section: Ionization Of Thesupporting

confidence: 76%

“…′′ 3 yr −1 , similar to other optical and infrared knots, leading to its identification as an "X-ray jet" (Güdel et al 2012;Rodríguez et al 2012). The on-source X-ray emission consists of a hard, flaring component with L X ∼ 10 30 erg s −1 and T X ∼ 30 MK and a soft, steadier component with L X and T X roughly an order of magnitude lower than those of the hard component (Güdel et al 2008).…”

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confidence: 58%

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THE [Ne iii] JET OF DG Tau AND ITS IONIZATION SCENARIOS

Liu

Shang

Herczeg

et al. 2016

ApJ

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Forbidden neon emission from jets of low-mass young stars can be used to probe the underlying highenergy processes in these systems. We analyze spectra of the jet of DG Tau obtained with the Very Large Telescope/X-Shooter spectrograph in 2010. [Ne iii] λ3869 is clearly detected in the innermost 3 ′′ microjet and the outer knot located at ∼ 6. ′′ 5. The velocity structure of the inner microjet can be decomposed into the low-velocity component (LVC) at ∼ −70 km s −1 and the high-velocity component (HVC) at ∼ −180 km s −1 . Based on the observed [Ne iii] flux and its spatial extent, we suggest the origins of the [Ne iii] emission regions and their relation with known X-ray sources along the jet. The flares from the hard X-ray source close to the star may be the main ionization source of the innermost microjet. The fainter soft X-ray source at 0.′′ 2 from the star may provide sufficient heating to help to sustain the ionization fraction against the recombination in the flow. The outer knot may be reionized by shocks faster than 100 km s −1 such that [Ne iii] emission reappears and that the soft X-ray emission at 5.′′ 5 is produced. Velocity decomposition of the archival Hubble Space Telescope spectra obtained in 1999 shows that the HVC had been faster, with a velocity centroid of ∼ −260 km s −1 . Such a decrease in velocity may potentially be explained by the expansion of the stellar magnetosphere, changing the truncation radius and thus the launching speed of the jet. The energy released by magnetic reconnections during relaxation of the transition can heat the gas up to several tens of megakelvin and provide the explanation for on-source keV X-ray flares that ionize the neon microjet.

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Section: Ionization Of Thesupporting

confidence: 76%

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confidence: 58%

THE [Ne iii] JET OF DG Tau AND ITS IONIZATION SCENARIOS

Liu

Shang

Herczeg

et al. 2016

ApJ

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“…DG Tau and RW Aur A show a collimated jet, and the spatial intervals of the knots and their proper motions suggest intervals of such mass ejection of 2.5-5 yr for DG Tau (Pyo et al 2003;Agra-Amboage et al 2011;Rodríguez et al 2012), and 3-20 yr for RW Aur A (López-Martín et al 2003). In the case of XZ Tau, the observations of the bubble-like flows and simulations suggest intervals of episodic mass ejection of 5-10 yr (Krist et al 2008).…”

Section: Long-term Variations In Line Profiles Equivalent Widths Anmentioning

confidence: 87%

Time Variability of Emission Lines for Four Active T Tauri Stars. I. October–december in 2010

Chou

Takami

Manset

et al. 2013

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We present optical spectrophotometric monitoring of four active T Tauri stars (DG Tau, RY Tau, XZ Tau, RW Aur A) at high spectral resolution (R 1 × 10 4 ), to investigate the correlation between time variable mass ejection seen in the jet/wind structure of the driving source and time variable mass accretion probed by optical emission lines. This may allow us to constrain the understanding of the jet/wind launching mechanism, the location of the launching region, and the physical link with magnetospheric mass accretion. In 2010, observations were made at six different epochs to investigate how daily and monthly variability might affect such a study. We perform comparisons between the line profiles we observed and those in the literature over a period of decades and confirm the presence of time variability separate from the daily and monthly variability during our observations. This is so far consistent with the idea that these line profiles have a long-term variability (3-20 yr) related to episodic mass ejection suggested by the structures in the extended flow components. We also investigate the correlations between equivalent widths and between luminosities for different lines. We find that these correlations are consistent with the present paradigm of steady magnetospheric mass accretion and emission line regions that are close to the star.

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“…Reports of radio variability from protostellar jets in literature have been sporadic and mostly related to the intrinsic variability of the central exciting sources of the jets (Galván-Madrid, Avila & Rodríguez 2004; Rodríguez et al 2012;Reipurth et al 2002). There have been instances where UV, optical and infrared variability in the emission from Herbig-Haro objects have been investigated (Brugel et al 1985;Liseau et al 1996;Raga et al 2016).…”

Section: Variability In Radio Flux Densitiesmentioning

confidence: 99%

Detection of non-thermal emission from the massive protostellar jet HH80-81 at low radio frequencies using GMRT

Vig

Veena

Mandal

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Low radio frequencies are favourable for the identification of emission from non-thermal processes such as synchrotron emission. The massive protostellar jet associated with IRAS 18162-2048 (also known as the HH80-81 system) has been imaged at low radio frequencies: 325, 610 and 1300 MHz, using the Giant Metrewave Radio Telescope, India. This is the first instance of detection of non-thermal emission from a massive protostellar jet at such low radio frequencies. The central region displays an elongated structure characteristic of the jet. In addition, the associated Herbig-Haro objects such as HH80, HH81, HH80N, and other condensations along the inner regions of the jet exhibit negative spectral indices. The spectral indices of most condensations are ∼ −0.7, higher than the value of −0.3 determined earlier using high frequency measurements. The magnetic field values derived using radio flux densities in the present work, under the assumption of equipartition near minimum energy condition, lie in the range 116 − 180 µG. We probe into the hard X-ray nature of a source that has been attributed to HH80, in an attempt to reconcile the non-thermal characteristics of radio and X-ray measurements. The flux densities of condensations at 610 MHz, measured nearly 11 yrs apart, display variability that could be ascribed to the cooling of condensations, and emphasize the importance of coeval or nearly-coeval measurements for estimation of spectral indices.

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Radio continuum emission from knots in the DG Tauri jet

Cited by 39 publications

References 30 publications

THE [Ne iii] JET OF DG Tau AND ITS IONIZATION SCENARIOS

THE [Ne iii] JET OF DG Tau AND ITS IONIZATION SCENARIOS

Time Variability of Emission Lines for Four Active T Tauri Stars. I. October–december in 2010

Detection of non-thermal emission from the massive protostellar jet HH80-81 at low radio frequencies using GMRT

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