Does the magnetic field suppress fragmentation in massive dense cores?. (arXiv:2010.12099v2 [astro-ph.GA] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Palau_A/0/1/0/all/0/1">Aina Palau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_Q/0/1/0/all/0/1">Qizhou Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Girart_J/0/1/0/all/0/1">Josep M. Girart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_J/0/1/0/all/0/1">Junhao Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rao_R/0/1/0/all/0/1">Ram Rao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koch_P/0/1/0/all/0/1">Patrick M. Koch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Estalella_R/0/1/0/all/0/1">Robert Estalella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_H/0/1/0/all/0/1">Huei-Ru Vivien Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_H/0/1/0/all/0/1">Hauyu Baobab Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qiu_K/0/1/0/all/0/1">Keping Qiu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_Z/0/1/0/all/0/1">Zhi-Yun Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zapata_L/0/1/0/all/0/1">Luis A. Zapata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bontemps_S/0/1/0/all/0/1">Sylvain Bontemps</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ho_P/0/1/0/all/0/1">Paul T. P. Ho</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beuther_H/0/1/0/all/0/1">Henrik Beuther</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ching_T/0/1/0/all/0/1">Tao-Chung Ching</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shinnaga_H/0/1/0/all/0/1">Hiroko Shinnaga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ahmadi_A/0/1/0/all/0/1">Aida Ahmadi</a>
Theoretical and numerical works indicate that a strong magnetic field should
suppress fragmentation in dense cores. However, this has never been tested
observationally in a relatively large sample of fragmenting massive dense
cores. Here we use the polarization data obtained in the Submillimeter Array
Legacy Survey of Zhang et al. to build a sample of 18 massive dense cores where
both fragmentation and magnetic field properties are studied in a uniform way.
We measured the fragmentation level, Nmm, within the field of view common to
all regions, of 0.15 pc, with a mass sensitivity of about 0.5 Msun, and a
spatial resolution of about 1000 au. In order to obtain the magnetic field
strength using the Davis-Chandrasekhar-Fermi method, we estimated the
dispersion of the polarization position angles, the velocity dispersion of the
H13CO+(4-3) gas, and the density of each core, all averaged within 0.15 pc. A
strong correlation is found between Nmm and the average density of the parental
core, although with significant scatter. When large-scale systematic motions
are separated from the velocity dispersion and only the small-scale (turbulent)
contribution is taken into account, a tentative correlation is found between
Nmm and the mass-to-flux ratio, as suggested by numerical and theoretical
works.
Theoretical and numerical works indicate that a strong magnetic field should
suppress fragmentation in dense cores. However, this has never been tested
observationally in a relatively large sample of fragmenting massive dense
cores. Here we use the polarization data obtained in the Submillimeter Array
Legacy Survey of Zhang et al. to build a sample of 18 massive dense cores where
both fragmentation and magnetic field properties are studied in a uniform way.
We measured the fragmentation level, Nmm, within the field of view common to
all regions, of 0.15 pc, with a mass sensitivity of about 0.5 Msun, and a
spatial resolution of about 1000 au. In order to obtain the magnetic field
strength using the Davis-Chandrasekhar-Fermi method, we estimated the
dispersion of the polarization position angles, the velocity dispersion of the
H13CO+(4-3) gas, and the density of each core, all averaged within 0.15 pc. A
strong correlation is found between Nmm and the average density of the parental
core, although with significant scatter. When large-scale systematic motions
are separated from the velocity dispersion and only the small-scale (turbulent)
contribution is taken into account, a tentative correlation is found between
Nmm and the mass-to-flux ratio, as suggested by numerical and theoretical
works.
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