The study of the disk rotation curve of our Galaxy at large distances provides an interesting scenario for us to test whether magnetic fields should be considered as a non-negligible dynamical ingredient. By assuming a bulge, an exponential disk for the stellar and gaseous distributions, and a dark halo and disk magnetic fields, we fit the rotation velocity of the Milky Way. In general, when the magnetic contribution is added to the dynamics, a better description of the rotation curve is obtained. Our main conclusion is that magnetic fields should be taken into account for the Milky Way dynamics. Azimuthal magnetic field strengths of B phi ~ 2 μG at distances of ~2 R0(i.e. 16 kpc) are able to explain the rise-up for the rotation curve in the outer disk.
It may interest you
Planetary nebulae (PNe) are the ejecta of evolved low-intermediate mass stars present in all stellar systems. Perhaps the easiest thing to do when studying PNe in a galaxy is just counting how many of them appear with a given luminosity, the Planetary Nebula Luminosity Function (PNLF). Not surprisingly, just a few very bright, and many more fainter, PNe populate the PNLF. But, most surprisingly, the bright end bin of the PNLF has a remarkably constant cut-off value in all galaxies and stellar systems studied so far, both young and old, with just a mild, calibrateable dependence onAdvertised on
We present 12 epochs of optical spectroscopy taken across the discovery outburst of the black hole (BH) candidate MAXI J1803-298 with the Gran Telescopio Canarias and Very Large Telescope. The source followed a standard outburst evolution. This means it passed through the so-called "hard" and "soft" states, defined in terms of the relative contribution of high to low energy X-rays. The system displays a "triangular" shape in the hardness intensity diagram, consistent with that seen in high-inclination BH transients and the previously reported detection of X-ray dips. The two epochs observedAdvertised on
Active galactic nuclei (AGN) consist of a supermassive black hole fed by the circumnuclear material close to the galaxy center. Around 10% of the AGNs develop a pair of jets that are launched to the interstellar medium at speed close to velocity of light. Blazars are observed when one of the jets points very close to our line of sight, which produce an extraordinary boosting of the emission by relativistic effects. Jets produce electromagnetic emission that varies rapidly and covers from radio waves to gamma rays. The observed light is mostly random without an apparent pattern. The source BLAdvertised on