We investigate, through 2D MHD numerical simulations, the interaction of a uniform magnetic field oblique to a moving interstellar cloud. In particular we explore the transformation of cloud kinetic energy into magnetic energy as a result of field line stretching. Some previous simulations have emphasized the possible dynamical importance of a “magnetic shield” formed around clouds when the mag...

[1] A thermomechanical ice sheet model (ISM) is used to investigate the sensitivity of the Laurentide and Fennoscandian ice sheets to tropical sea surface temperature (SST) perturbations during deglaciation. The ISM is driven by surface temperature and precipitation fields from three different atmospheric general circulation models (AGCMs). For each AGCM, the responses in temperature and precip...

We have investigated the physical and chemical status of the pre-protostellar core B68. A previous extinction study suggested that the density profile of B68 is remarkably consistent with a Bonnor-Ebert sphere with 2.1 M at 16 K. We mapped B68 in C3H2, CCS, and NH3 with the Deep Space Network (DSN) 70m telescope at Goldstone. Our results show that the NH3 peak coincides with the dust continuum ...

We have computed line emission cooling rates for the main cooling species in models of interstellar molecular clouds. The models are based on numerical simulations of super–sonic magneto–hydrodynamic (MHD) turbulence. Non-LTE radiative transfer calculations have been performed to properly account for the complex density and velocity structures in the MHD simulations. Three models are used. Two ...

Fragmentation process in a cylindrical magnetized cloud is studied with the nested grid method. The nested grid scheme use 15 levels of grids with different spatial resolution overlaid subsequently, which enables us to trace the evolution from the molecular cloud density ∼ 100cm−3 to that of the protostellar disk ∼ 1010cm−3 or more. Fluctuation with small amplitude grows by the gravitational in...

We estimate minimum energy magnetic fields (Bmin) for a sample of galaxies with measured gas surface densities. The sample spans more than four orders of magnitude in surface density from normal spirals to luminous starbursts. We show that the ratio of the minimum energy magnetic pressure to the total pressure in the ISM decreases substantially with increasing surface density. For the ultra-lum...

The recent availability of high-resolution far-infrared (FIR) polarization observations galaxies using HAWC+/SOFIA has facilitated studies extragalactic magnetic fields in the cold and dense molecular disks. We investigate whether any significant structural differences are detectable kiloparsec-scale field grand design face-on spiral galaxy M51 when traced within diffuse (radio) interstellar me...

In two previous papers we formulated and solved, for a fiducial set of free parameters, the problem of the formation and evolution of a magnetically supercritical core inside a magnetically subcritical parent cloud. The evolution was followed into the opaque phase that resulted in the formation of a hydrostatic protostellar core. In this paper we present a parameter study to assess the sensitiv...

We propose that giant flares on Soft Gamma-Ray Repeaters produce relativistic, strongly magnetized, weakly baryon loaded magnetic clouds, somewhat analogous to solar coronal mass ejection (CME) events. Flares are driven by unwinding of internal non-potential magnetic fields which leads to slow build-up of magnetic energy outside of the neutron star. For large magnetospheric currents, correspond...

In a quest for better understanding the shaping mechanism of planetary nebulae (PNs) I published many papers in the past (e.g., Soker 2004a) all of which came to the same conclusion: For the formation of non-spherical PNs a companion is required, wether stellar or substellar. This results from the basic assumption that angular momentum is a conserved physics quantity. As trivial as this may sou...