6 research outputs found
Magnetic field evolution in interacting galaxies
Violent gravitational interactions can change the morphologies of galaxies
and, by means of merging, transform them into elliptical galaxies. We aim to
investigate how they affect the evolution of galactic magnetic fields. We
selected 16 systems of interacting galaxies and compared their radio emission
and estimated magnetic field strengths with their star-forming activity,
far-infrared emission, and the stage of tidal interaction. We find a general
evolution of magnetic fields: for weak interactions the strength of magnetic
field is almost constant (10-15muG) as interaction advances, then it increases
up to 2x, peaks at the nuclear coalescence (25muG), and decreases again, down
to 5-6muG, for the post-merger remnants. The magnetic field strength for whole
galaxies is weakly affected by the star formation rate (SFR), while the
dependence is higher for galactic centres. We show that the morphological
distortions visible in the radio total and polarized emission do not depend
statistically on the global or local SFRs, while they do increase with the
advance of interaction. The constructed radio-far-infrared relations for
interacting and non-interacting galaxies display a similar balance between the
generation of cosmic rays, magnetic fields, and the production of the thermal
energy and dust radiation. The process of strong gravitational interactions can
efficiently magnetize the merger's surroundings, having a similar magnetizing
effect on intergalactic medium as supernova explosions or galactic winds. If
interacting galaxies generate some ultra-high energy cosmic rays (UHECRs), the
disk or magnetized outflows can deflect them (up to 23 degrees), and make an
association of the observed UHECRs with the sites of their origin very
uncertain.Comment: 17 pages, 16 figures, 5 tables. Published in Astronomy and
Astrophysics, minor changes to v
Carbon-13 longitudinal relaxation time measurements and DFT-GIAO NMR computations for two ammonium ions of a tetraazamacrocyclic scorpiand system
Spin-lattice relaxation times, T1s, for 13C nuclei in two cations Hn1n+ (n
= 1, 5)of N-(2-amino-ethyl)-cyclam (1, scorpiand) were determined by means
of 13C{1H} NMR experiments in aqueous solution at pH 11.5 and 0.2. The
theoretical study [modeling with OPLS-AA, B3LYP/6-31G(d) geometry
optimizations, dispersion-corrected energies (DFT-D3), and DFT-GIAO
predictions of the NMR chemical shifts (including an IEF-PCM simulation of
hydration)] was also done for several conformers of the tautomer iso-H414+
not investigated before. The binding directions in protonated polyamino
receptors necessary for efficient complexation of the nitrate anion(s)
were briefly outlined, as well. All these results were discussed in terms
of 'abnormal' 13C chemical shift changes found previously for the
side-chain carbons of amine 1 in strongly acidic solution (HNO3). In
conclusion, an earlier proposal of its association with NO3- at pH=1 was
rejected. Instead, the participation of small amounts of a microspecies
iso-H414+Dhydr under such conditions can be proposed.Publikacja w ramach programu Springer Open Choice/Open Access finansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego i realizowanego w ramach umowy na narodową licencję akademicką na czasopisma Springer w latach 2010-2013