Spectrophotometric Study Explores an Early-Type Dwarf Galaxy CGCG014-074

Argentinian astronomers utilized the Gemini Observatory for extensive photometric and spectroscopic observations of CGCG014-074, known as an early-type dwarf galaxy. Their findings, released on September 3 in the Monthly Notices of the Royal Astronomical Society, provide deeper insight into the properties and evolution of this galaxy.

Dwarf galaxies are characterized by their low luminosity and mass, typically containing a few billion stars. Among these, early-type dwarf galaxies are prevalent, representing the dominant galaxy type in the local universe.

CGCG014-074 is classified as an early-type lenticular dwarf galaxy and resides near the large lenticular galaxy NGC 4546, situated about 46 million light years from Earth. While it has a heliocentric velocity measured at 998 km/s, limited information exists regarding CGCG014-074 due to its previous status as largely unexplored.

To change this, a team of astronomers led by Natalia Guevara from the National University of La Plata, Argentina, employed the Gemini Multi-Object Spectrographs (GMOS) at the Gemini South telescope in Chile for a thorough spectrophotometric study of CGCG014-074.

The researchers stated, "This paper presents the photometric and spectroscopic analysis of the early-type dwarf galaxy CGCG014-074. We obtained observations using GMOS South, employing broadband filters 𝑔′, 𝑟′, 𝑖′, and 𝑧′, alongside long-slit spectroscopic data from the same instrument."

Their observations revealed unique characteristics of CGCG014-074, including a rotating inner disk, a spanning stellar formation that halted around two billion years ago, and boxy isophotes at its outskirts. Notably, the study found no signs of a kinematically decoupled core or evidence of any major mergers occurring.

According to their findings, CGCG014-074 consists of a total stellar mass of 330 million solar masses and exhibits a total dynamical mass of 800 million solar masses. These values align well with those for other early-type dwarf galaxies.

The data collected indicate CGCG014-074 features an old, metal-poor nucleus, aged approximately 9.3 billion years, with a metallicity of -0.84 dex. In contrast, its stellar disk is younger, around 4.4 billion years, and has a higher metallicity of approximately -0.40 dex.

The authors note that CGCG014-074 experienced a lengthy period of stellar formation, lasting until about two billion years ago, when its star formation ceased. At that time, it achieved 100% of its stellar mass. Based on their findings, they view CGCG014-074 as a likely building block galaxy that has passively evolved throughout its history.

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