Letter to the Editor

A slow bar in the lenticular barred galaxy NGC 4277^⋆

¹ Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
e-mail: chiara.buttitta@phd.unipd.it
² INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 2, 35122 Padova, Italy
³ Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama, Avenida Copayapu 485, Copiapó, Chile
⁴ Departamento de Astrofísica, Universidad de La Laguna, Avenida Astrofísico Francisco Sánchez s/n, 38206 Tenerife, Spain
⁵ Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
⁶ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany
⁷ Centro de Astrobiología (CSIC-INTA), Ctra de Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
⁸ Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK
⁹ INAF – Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy

Received: 17 June 2022
Accepted: 1 August 2022

Abstract

Aims. We characterised the properties of the bar hosted in lenticular galaxy NGC 4277, which is located behind the Virgo cluster.

Methods. We measured the bar length and strength from the surface photometry obtained from the broad-band imaging of the Sloan Digital Sky Survey and we derived the bar pattern speed from the stellar kinematics obtained from the integral-field spectroscopy performed with the Multi Unit Spectroscopic Explorer at the Very Large Telescope. We also estimated the co-rotation radius from the circular velocity, which we constrained by correcting the stellar streaming motions for asymmetric drift, and we finally derived the bar rotation rate.

Results. We found that NGC 4277 hosts a short (R_bar = 3.2_−0.6^+0.9 kpc), weak (S_bar = 0.21 ± 0.02), and slow (ℛ = 1.8_−0.3^+0.5) bar and its pattern speed (Ω_bar = 24.7 ± 3.4 km s⁻¹ kpc⁻¹) is amongst the best-constrained ones ever obtained with the Tremaine–Weinberg (TW) method with relative statistical errors of ∼0.2.

Conclusions. NGC 4277 is the first clear-cut case of a galaxy hosting a slow stellar bar (ℛ > 1.4 at more than a 1σ confidence level) measured with the model-independent TW method. A possible interaction with the neighbour galaxy NGC 4273 could have triggered the formation of such a slow bar and/or the bar could be slowed down due to the dynamical friction with a significant amount of dark matter within the bar region.