High resolution submillimeter observations of massive protostars

Brogan, C. L.; Hunter, T. R.; Indebetouw, R.; Chandler, Claire J.; Shirley, Yancy L.; Rao, Ramprasad; Sarma, A. P.

doi:10.1007/s10509-007-9598-1

Cited by 9 publications

(11 citation statements)

References 18 publications

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“…Observational evidence for an accretion disk is controversial. A structure oriented NE-SW is observed in the mid-infrared (De Buizer & Minier 2005), as is a velocity gradient in the molecular lines (Brogan et al 2008;Klaassen et al 2009;Beuther et al 2012;Zhu et al 2013). A NW-SE velocity gradient of ∼ 0.02 km s −1 AU −1 found in methanol masers (Minier et al 1998(Minier et al , 2000 was modeled as a circumstellar disk (Pestalozzi et al 2004).…”

Section: Introductionmentioning

confidence: 95%

NGC 7538 Irs. 1. Interaction of a Polarized Dust Spiral and a Molecular Outflow

Wright

Hull

Pillai

et al. 2014

ApJ

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We present dust polarization and CO molecular line images of NGC 7538 IRS 1. We combined data from the SMA, CARMA and JCMT telescopes to make images with ∼ 2.5 ′′ resolution at 230 and 345 GHz. The images show a remarkable spiral pattern in both the dust polarization and molecular outflow. These data dramatically illustrate the interplay between a high infall rate onto IRS 1 and a powerful outflow disrupting the dense, clumpy medium surrounding the star. The images of the dust polarization and the CO outflow presented here provide observational evidence for the exchange of energy and angular momentum between the infall and the outflow. The spiral dust pattern, which rotates through over 180 • from IRS 1, may be a clumpy filament wound up by conservation of angular momentum in the infalling material. The redshifted CO emission ridge traces the dust spiral closely through the MM dust cores, several of which may contain protostars. We propose that the CO maps the boundary layer where the outflow is ablating gas from the dense gas in the spiral.

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Section: Introductionmentioning

confidence: 95%

NGC 7538 Irs. 1. Interaction of a Polarized Dust Spiral and a Molecular Outflow

Wright

Hull

Pillai

et al. 2014

ApJ

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“…Toward this end, the past decade of advances in (sub)millimeter interferometry has enabled the identification of proto-Trapezium-like systems, termed "protoclusters" (e.g., Hunter et al 2006;Beuther et al 2007b;Rodón et al 2008), in which four or more compact millimeter continuum sources exist within a projected diameter of 10,000 AU. In many cases, the protocluster members present a striking diversity in star formation indicators-including the presence or absence of H 2 O masers, hot core line emission, and free-free emission-providing strong evidence that closely neighboring objects can exist in different evolutionary stages of formation (Zhang et al 2007;Cyganowski et al 2007;Brogan et al 2008Brogan et al , 2011Zinchenko et al 2012). At last count of the literature, half of these massive cores studied at 1000 AU resolution were resolved into four or more millimeter sources (Palau et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Subarcsecond Imaging of the NGC 6334 I(n) Protocluster: Two Dozen Compact Sources and a Massive Disk Candidate

Hunter

Brogan

Cyganowski

et al. 2014

ApJ

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Using the Submillimeter Array (SMA) and Karl G. Jansky Very Large Array, we have imaged the massive protocluster NGC 6334 I(N) at high angular resolution (0. 5 ∼ 650 AU) from 6 cm to 0.87 mm, detecting 18 new compact continuum sources. Three of the new sources are coincident with previously identified H 2 O masers. Together with the previously known sources, these data bring the number of likely protocluster members to 25 for a protostellar density of ∼700 pc −3 . Our preliminary measurement of the Q-parameter of the minimum spanning tree is 0.82-close to the value for a uniform volume distribution. All of the (nine) sources with detections at multiple frequencies have spectral energy distributions consistent with dust emission, and two (SMA 1b and SMA 4) also have long wavelength emission consistent with a central hypercompact H ii region. Thermal spectral line emission, including CH 3 CN, is detected in six sources: LTE model fitting of CH 3 CN (J = 12-11) yields temperatures of 72-373 K, confirming the presence of multiple hot cores. The fitted LSR velocities range from −3.3 to −7.0 km s −1 , with an unbiased mean square deviation of 2.05 km s −1 , implying a protocluster dynamical mass of 410 ± 260 M . From analysis of a wide range of hot core molecules, the kinematics of SMA 1b are consistent with a rotating, infalling Keplerian disk of diameter 800 AU and enclosed mass of 10-30 M that is perpendicular (within 1• ) to the large-scale bipolar outflow axis. A companion to SMA 1b at a projected separation of 0. 45 (590 AU; SMA 1d), which shows no evidence of spectral line emission, is also confirmed. Finally, we detect one 218.4400 GHz and several 229.7588 GHz Class-I CH 3 OH masers.

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“…Though it seems likely that the peak of CH 3 CN emission is associated with the powering source of the small-scale SiO outflow, its connection to the somewhat more extended molecular emission at this systemic velocity (cf. Brogan et al 2007) remains to be confirmed.…”

Section: Discussion and Open Issuesmentioning

confidence: 93%

“…The observed chemical differentiation between clumps (cf. Brogan et al 2007;Schilke et al 2007;Comito et al 2007) is a further indication of the unlikelihood of a rotating accretion disk over a 1 spatial extension. A rotating accretion disk around HW2 is likely to exist, but it must be searched for on a smaller scale.…”

Section: Discussion and Open Issuesmentioning

confidence: 99%

High-resolution mm interferometry and the search for massive protostellar disks: the case of Cep-A HW2

Comito

Schilke

Endesfelder

et al. 2007

Astrophys Space Sci

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The direct detection of accretion onto massive protostars through rotating disks constitutes an important tile in the massive-star-formation-theory mosaic. This task is however observationally very challenging. A very interesting example is Cepheus A HW2. The properties of the molecular emission around this YSO seems to suggest the presence of a massive rotating disk (cf. Patel et al. in Nature 437:109, 2005). We have carried out sub-arcsec-resolution PdBI observations of high-density and shock tracers such as SO 2 , SiO, CH 3 CN, and CH 3 OH towards the center of the outflow. A detailed analysis of the spatial distribution and of the velocity field traced by all observed species leads us to conclude that, on a ∼700 AU scale, the Cep-A "disk" is actually the result of the superposition of multiple hotcore-type objects, at least one of them ejecting an outflow at a small angle with respect to the line of sight. Together with the well-known large-scale outflow ejected by HW2, this setup makes for a very complex spatial and kinematic picture.Keywords High-mass star formation · Millimeter-wavelength radioastronomy · Millimeter interferometry · High-mass disks Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).C. Comito ( ) · P. Schilke · U. Endesfelder

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High resolution submillimeter observations of massive protostars

Cited by 9 publications

References 18 publications

NGC 7538 Irs. 1. Interaction of a Polarized Dust Spiral and a Molecular Outflow

NGC 7538 Irs. 1. Interaction of a Polarized Dust Spiral and a Molecular Outflow

Subarcsecond Imaging of the NGC 6334 I(n) Protocluster: Two Dozen Compact Sources and a Massive Disk Candidate

High-resolution mm interferometry and the search for massive protostellar disks: the case of Cep-A HW2

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