The metal-poor dwarf irregular galaxy candidate next to Mrk 1172

• Autor(a) principal: Lassen, Augusto Eduardo
• Data de Publicação: 2021
• Outros Autores: Riffel, Rogério, Chies-Santos, Ana Leonor, Johnston, Evelyn J., Haußler, Boris, Azevedo, Gabriel Maciel, Dutra, Daniel Ruschel, Riffel, Rogemar André
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/235073
• topic: Galáxias anãs; Metalicidade; Populacoes estelares; Formacao de estrelas; ISM : Abundances; H II regions; Galaxies : Dwarf

In this work, we characterize the properties of the object SDSS J020536.84−081424.7, an extended nebular region with projected extension of 14 × 14 kpc2 in the line of sight of the ETG Mrk 1172, using unprecedented spectroscopic data from MUSE. We perform a spatially resolved stellar population synthesis and estimate the stellar mass for both Mrk 1172 (1 × 1011 M ) and our object of study (3 × 109 M ). While the stellar content of Mrk 1172 is dominated by an old (∼10 Gyr) stellar population, the extended nebular emission has its light dominated by young to intermediate age populations (from ∼100 Myr to ∼1 Gyr) and presents strong emission lines such as H β; [O III] λλ4959, 5007 Å; H α; [N II] λλ6549, 6585 Å; and [S II] λλ6717, 6732 Å. Using these emission lines, we find that it is metal poor (with Z ∼ 1/3 Z , comparable to the LMC) and is actively forming stars (0.70 M yr−1), especially in a few bright clumpy knots that are readily visible in H α. The object has an ionized gas mass ≥3.8 × 105 M . Moreover, the motion of the gas is well described by a gas in circular orbit in the plane of a disc and is being affected by interaction wtih Mrk 1172. We conclude that SDSS J020536.84−081424.7 is most likely a dwarf irregular galaxy (the dIGal).