Spectrophotometric study explores early-type dwarf galaxy

Using the Gemini Observatory, Argentine astronomers have carried out comprehensive photometric and spectroscopic observations of an early-type dwarf galaxy known as CGCG014-074. The results of the observation campaign, published on September 3 in the journal Monthly Notices of the Royal Astronomical Societywill shed more light on the properties and evolution of this galaxy.

In general, dwarf galaxies are low-luminosity, low-mass star systems, typically containing a few billion stars. Within this group, early-type dwarf galaxies stand out as the dominant galaxy type in the local universe.

CGCG014-074 is an early-type dwarf lenticular galaxy located in the vicinity of NGC 4546, a massive lenticular galaxy located at a distance of about 46 million light-years. Apart from a heliocentric velocity of 998 km/s, little is known about the properties of CGCG014-074, as the galaxy remains completely unexplored.

That’s why a team of astronomers led by Natalia Guevara of the National University of La Plata in Argentina used Gemini Multi-Object Spectrographs (GMOS) at the Gemini South telescope in Chile to carry out a complete spectrophotometric study of CGCG014-074.

“This paper presents the photometric and spectroscopic analysis of the early-type dwarf galaxy CGCG014-074. The observations were obtained with the GMOS South instrument of the Gemini Observatory. The photometric data were obtained using the broadband filters 𝑔′, 𝑟′, 𝑖′ and 𝑧′, while the spectroscopic observations were made in the long-slit mode of the same instrument,” the researchers wrote.

Observations revealed that CGCG014-074 has distinct features, including a rotating inner disk, extensive star formation with a cessation of activity about two billion years ago, and box-shaped isophotes toward its outer regions. The study detected no evidence of a kinematically decoupled core, nor any evidence of a major merger.

According to the study, CGCG014-074 has a total stellar mass of 330 million solar masses and a total dynamical mass of 800 million solar masses. These results agree well with values ​​obtained for other early-type dwarf galaxies.

The collected data indicate that CGCG014-074 has an old, metal-poor core, about 9.3 billion years old and with a metallicity of -0.84 dex. In contrast, its stellar disk is younger (about 4.4 billion years old) and has a higher metallicity (about -0.40 dex).

The authors of the study conclude that CGCG014-074 experienced a prolonged period of star formation from its inception until about two billion years ago, when its star formation ceased and it reached 100% of its stellar mass. Therefore, based on the new study, they perceive CGCG014-074 as a likely building block galaxy that evolved passively throughout its history.

© 2024 Science X Network