Letter to the Editor

The VISCACHA survey

III. Star clusters counterpart of the Magellanic Bridge and Counter-Bridge in 8D^⋆

¹ Instituto de Alta Investigación, Sede Esmeralda, Universidad de Tarapacá, Av. Luis Emilio Recabarren 2477, Iquique, Chile
e-mail: bdiasm@academicos.uta.cl
² , Av. Monsenhor Luiz de Gonzaga, 103, 37250-000 Nepomuceno, MG, Brazil
³ Universidade de São Paulo, IAG, Rua do Matão 1226, Cidade Universitária, São Paulo 05508-900, Brazil
⁴ Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ, Brazil
⁵ Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, X5000BGR Córdoba, Argentina
⁶ Instituto de Astronomía Teórica y Experimental (CONICET-UNC), Laprida 854, X5000BGR Córdoba, Argentina
⁷ Facultad de Ciencias Astronómicas y Geofísicas de la Universidad Nacional de La Plata, and Instituto de Astrofísica de La Plata (CCT La Plata – CONICET, UNLP), Paseo del Bosque s/n, B1900FWA La Plata, Argentina
⁸ Consejo Nacional de Investigaciones Científicas y Técnicas, Godoy Cruz 2290, C1425FQB Ciudad Autónoma de Buenos Aires, Argentina
⁹ Departamento de Ciências Exatas e Tecnológicas, UESC, Rodovia Jorge Amado km 16, 45662-900 Ilhéus, Brazil
¹⁰ Departamento de Astronomia, IF – UFRGS, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, Brazil
¹¹ Departamento de Física y Astronomía, Universidad de La Serena, Avenida Juan Cisternas 1200, La Serena, Chile
¹² Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, Universidad de La Serena Benavente 980, La Serena, Chile
¹³ Departmento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
¹⁴ Instituto de Astronomía, Universidad Nacional Autonóma de México, Apartado Postal 106, C.P. 22800 Ensenada, Baja California, Mexico
¹⁵ Gemini Observatory/NSF’s NOIRLab, Casilla 603, La Serena, Chile
¹⁶ Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena, Chile
¹⁷ Departamento de Física, ICEx – UFMG, Av. Antônio Carlos 6627, Belo Horizonte 31270-901, Brazil
¹⁸ Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Avenida dos Estados, 5001, 09210-580 Santo André, Brazil

Received: 30 November 2020
Accepted: 26 February 2021

Abstract

Context. The interactions between the Small and Large Magellanic Clouds (SMC and LMC) created the Magellanic Bridge; a stream of gas and stars pulled out of the SMC towards the LMC about 150 Myr ago. The tidal counterpart of this structure, which should include a trailing arm, has been predicted by models but no compelling observational evidence has confirmed the Counter-Bridge so far.

Aims. The main goal of this work is to find the stellar counterpart of the Magellanic Bridge and Counter-Bridge. We use star clusters in the SMC outskirts as they provide a 6D phase-space vector, age, and metallicity which help characterise the outskirts of the SMC.

Methods. Distances, ages, and photometric metallicities were derived from fitting isochrones to the colour-magnitude diagrams from the VISCACHA survey. Radial velocities and spectroscopic metallicities were derived from the spectroscopic follow-up using GMOS in the CaII triplet region.

Results. Among the seven clusters analysed in this work, five belong to the Magellanic Bridge, one belongs to the Counter-Bridge, and the other belongs to the transition region.

Conclusions. The existence of the tidal counterpart of the Magellanic Bridge is evidenced by star clusters. The stellar component of the Magellanic Bridge and Counter-Bridge are confirmed in the SMC outskirts. These results are an important constraint for models that seek to reconstruct the history of the orbit and interactions between the LMC and SMC as well as constrain their future interaction including with the Milky Way.