Astronomy

by Filippo Pantellini 2020. The magnetosphere of Uranus is subject to strong seasonal variations. The variability is a consequence of the planet’s rotation axis being nearly parallel to its orbital plane, a situation unique in the Solar System. A short rotation period of 17.24h and a large angle between the […]

Numerous research topics rely on an improved cosmic distance scale (e.g., cosmology, gravitational waves) and the NASA/IPAC Extragalactic Database of Distances (NED-D) supports those efforts by tabulating multiple redshift-independent distances for 12,000 galaxies (e.g., Large Magellanic Cloud (LMC) zero-point). Six methods for securing a mean estimate distance (MED) from the data are presented (e.g., indicator and Decision Tree).

The color–stellar mass-to-light ratio relation (CMLR) is a widely accepted tool for estimating the stellar mass (M *) of a galaxy. However, an individual CMLR tends to give distinct M * for a same galaxy when it is applied in different bands. Examining five representative CMLRs from the literature, we find that the difference in M * predicted in different bands from optical to near-infrared by a CMLR is 0.1 ~ 0.3 dex.

The evolution of cosmic structures, the formation and growth of the first black holes and the connection to their baryonic environment are key unsolved problems in astrophysics. The X-ray Athena mission and the gravitational-wave Laser Interferometer Space Antenna (LISA) offer independent and complementary angles on these problems.