Synthetic observations of protostellar multiple systems

Lomax, Oliver David; Whitworth, Anthony Peter

doi:10.1093/mnras/stx3357

Cited by 2 publications

(1 citation statement)

References 51 publications

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“…In addition, the prevalence of episodic accretion has been invoked to explain the observed luminosity spread of protostars in clusters (see Jensen & Haugbølle 2018, and references therein), but whether this phenomenon has a predominant effect remains in question (Fischer et al 2017). Nevertheless, the impact of such outbursts on the surrounding protocluster, particularly from large accretion events in highmass protostars, is potentially a very important feedback mechanism in cluster formation (Lomax & Whitworth 2018;Stamatellos et al 2012).…”

Section: Introductionmentioning

confidence: 99%

The Extraordinary Outburst in the Massive Protostellar System NGC 6334I-MM1: Flaring of the Water Masers in a North–South Bipolar Outflow Driven by MM1B

Brogan

Hunter

Cyganowski

et al. 2018

ApJ

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We compare multi-epoch sub-arcsecond VLA imaging of the 22 GHz water masers toward the massive protocluster NGC 6334I observed before and after the recent outburst of MM1B in (sub)millimeter continuum. Since the outburst, the water maser emission toward MM1 has substantially weakened. Simultaneously, the strong water masers associated with the synchrotron continuum point source CM2 have flared by a mean factor of 6.5 (to 4.2 kJy) with highly-blueshifted features (up to 70 km s −1 from LSR) becoming more prominent. The strongest flaring water masers reside 3000 au north of MM1B and form a remarkable bow shock pattern whose vertex coincides with CM2 and tail points back to MM1B. Excited OH masers trace a secondary bow shock located ∼120 au downstream. ALMA images of CS (6-5) reveal a highly-collimated north-south structure encompassing the flaring masers to the north and the non-flaring masers to the south seen in projection toward the MM3-UCHII region. Proper motions of the southern water masers over 5.3 years indicate a bulk projected motion of 117 km s −1 southward from MM1B with a dynamical time of 170 yr. We conclude that CM2, the water masers, and many of the excited OH masers trace the interaction of the high velocity bipolar outflow from MM1B with ambient molecular gas. The previously-excavated outflow cavity has apparently allowed the radiative energy of the current outburst to propagate freely until terminating at the northern bow shock where it strengthened the masers. Additionally, water masers have been detected toward MM7 for the first time, and a highly collimated CS (6-5) outflow has been detected toward MM4.

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Section: Introductionmentioning

confidence: 99%

The Extraordinary Outburst in the Massive Protostellar System NGC 6334I-MM1: Flaring of the Water Masers in a North–South Bipolar Outflow Driven by MM1B

Brogan

Hunter

Cyganowski

et al. 2018

ApJ

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Unraveling the Spectral Energy Distributions of Clustered YSOs

Martínez-Galarza

Protopapas

Smith

et al. 2018

ApJ

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Despite a significant body of evidence suggesting that intermediate-and high-mass stars form in clustered environments, how stars form when the available resources are shared is still not well understood. A related question is whether the IMF is in fact universal across galactic environments, a galactic initial mass function (IGIMF), or whether it is an average of IMFs that differ, for example, in massive versus low-mass molecular clouds. If the distribution of stellar masses depends on the birth environment, then the preferred modes of star formation must also vary, since not all models derive in self-regulated star formation. One of the long-standing problems in resolving these questions and in the study of young clusters is observational: accurately combining multi-wavelength datasets obtained using telescopes with different spatial resolutions. The emission from multiple sources is frequently seen as blended either because the cluster complexities are unresolved, because at different wavelengths or with different telescopes the beam sizes are different, or a combination of these. The confusion hinders our ability to fully characterize clustered star formation. Here we present a new method that uses a genetic algorithm and Bayesian inference to fit the blended SEDs and images of individual YSOS in confused clusters. We apply this method to the infrared photometry of a sample comprising 70 Spitzer -selected, low-mass (M cl < 100 M ) young clusters in the galactic plane, and use the derived physical parameters to investigate the distributions of masses and evolutionary stages of clustered YSOs, and the implications of those distributions for studies of the IMF and the different models of star formation. We find that for low-mass clusters composed of class I and class II YSOs, there exists a non-trivial relationship between the total stellar mass of the cluster (M cl ) and the mass of its most massive member (m max ). The properties of the derived correlation are most compatible with the random sampling of a Kroupa IMF, with a fundamental high-mass limit of 150 M . Our results are also compatible with SPH models that predict a dynamical termination of the accretion in protostars, with massive stars undergoing this stopping at later times in their evolution.

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Synthetic observations of protostellar multiple systems

Cited by 2 publications

References 51 publications

The Extraordinary Outburst in the Massive Protostellar System NGC 6334I-MM1: Flaring of the Water Masers in a North–South Bipolar Outflow Driven by MM1B

The Extraordinary Outburst in the Massive Protostellar System NGC 6334I-MM1: Flaring of the Water Masers in a North–South Bipolar Outflow Driven by MM1B

Unraveling the Spectral Energy Distributions of Clustered YSOs

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