We find a distinct stellar population in the counterrotating and kinematically decoupled core of the isolated massive elliptical galaxy NGC 1700. Coinciding with the edge of this core, we find a significant change in the slope of the gradient of various representative absorption line indices. Our age estimate for this core is markedly younger than the main body of the galaxy. We find lower values for the age, metallicity, and Mg/Fe abundance ratio in the center of this galaxy when we compare them with other isolated elliptical galaxies with similar velocity dispersion. We discuss the different possible scenarios that might have lead to the formation of this younger kinematically decoupled structure and conclude that, in light of our findings, the ingestion of a small stellar companion on a retrograde orbit is the most favored.
Advertised on
References
2011, ApJ, 732L, 33K
It may interest you
-
We present, for the first time, model spectra of single-age, single-metallicity stellar populations computed with the E-MILES evolutionary synthesis code incorporating an environment-dependent, variable galaxy-wide initial mass function (gwIMF). This gwIMF, calculated using the GalIMF code, is rooted in the integrated galactic initial mass function (IGIMF) theory, which predicts IMF variations as a function of the star formation rate and the metallicity. By coupling these two codes, we generated a comprehensive library of single-burst stellar population spectra uniquely sensitive to gwIMFAdvertised on -
Measuring galaxy sizes is essential for understanding how they were formed and evolved across time. However, traditional methods based on l ight concentration or isophotal densities often lack a clear physical meaning. A recent study from Trujillo+20 explores a more physically motivated definition: the radius R 1, where the stellar surface density falls to 1 solar masses per parsec square —roughly the threshold for gas to form stars in galaxies like the Milky Way. In this work, Arjona-Gálvez+25 uses over 1,000 galaxies from several state-of-the-art cosmological simulations (AURIGA, HESTIAAdvertised on -
The most massive stars in the universe are often born and evolve in binary and multiple systems — that is, in pairs or groups bound by their mutual gravity. Understanding how they interact with each other is key to explaining everything from their formation to the impact they have on the galaxies they inhabit. The MONOS project (Multiplicity Of Northern O-type Spectroscopic systems) aims to study these systems in the northern sky, combining spectroscopic observations (which analyze light split into its component colors to measure stellar velocities and physical properties) with photometryAdvertised on