In-Depth Study of Early-Type Dwarf Galaxy Revealed

Using the Gemini Observatory, astronomers from Argentina have conducted thorough photometric and spectroscopic studies on an early-type dwarf galaxy called CGCG014-074. The results of these observations, published on September 3 in the Monthly Notices of the Royal Astronomical Society, offer new insights into the properties and evolution of this galaxy.

Dwarf galaxies are typically characterized by their low luminosity and mass, usually containing a few billion stars. Among them, early-type dwarf galaxies are particularly prominent within the local universe.

CGCG014-074 is identified as an early-type dwarf lenticular galaxy and is situated near NGC 4546, a more massive lenticular galaxy about 46 million light-years away. Although it has a heliocentric velocity of 998 km/s, CGCG014-074 has remained relatively unexplored.

To address this, a team led by Natalia Guevara from the National University of La Plata in Argentina utilized the Gemini Multi-Object Spectrographs (GMOS) at the Gemini South telescope in Chile to perform an in-depth spectrophotometric analysis of CGCG014-074.

The team noted, "This study presents the photometric and spectroscopic analysis of the early-type dwarf galaxy CGCG014-074. The data were gathered using the GMOS South instrument at the Gemini Observatory. Photometric observations were carried out with broadband filters 𝑔′, 𝑟′, 𝑖′, and 𝑧′, while spectroscopic observations were performed using the long-slit mode of the same instrument."

The research uncovered several distinctive characteristics of CGCG014-074: it features a rotating inner disk, an extended phase of star formation that ceased around two billion years ago, and boxy isophotes in its outer regions. The study found no indications of a kinematically decoupled core or evidence of significant mergers.

The findings show that CGCG014-074 has a total stellar mass of 330 million solar masses and a total dynamical mass of 800 million solar masses, which is consistent with other early-type dwarf galaxies.

Additionally, the data suggest that CGCG014-074 possesses an ancient and metal-poor nucleus, estimated to be about 9.3 billion years old with a metallicity of −0.84 dex. In contrast, its stellar disk is younger (around 4.4 billion years old) and has a higher metallicity (approximately -0.40 dex).

The researchers conclude that CGCG014-074 likely experienced a prolonged period of star formation until about two billion years ago when it ceased forming new stars and achieved its current stellar mass. This indicates that CGCG014-074 might be a key building block galaxy that has evolved in a largely passive manner over time.