An ultra diffuse galaxy in the NGC 5846 group from the VEGAS survey

Forbes, Duncan A.; Gannon, Jonah S.; Couch, Warrick J.; Iodice, E.; Spavone, M.; Cantiello, M.; Napolitano, N. R.; Schipani, P.

doi:10.1051/0004-6361/201935499

Cited by 45 publications

(49 citation statements)

References 32 publications

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“…With MUSE we have followed up the dwarf galaxy MAT-LAS J15052031+0148447 (MATLAS-2019), which has a rich globular cluster system and is located in the NGC 5846 group of galaxies. The object turned out to have also been detected in the VEGAS survey by Forbes et al (2019). We obtained spectra of the stellar body and its GC candidates.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic study of MATLAS-2019 with MUSE: An ultra-diffuse galaxy with an excess of old globular clusters

Müller

Marleau

Duc

et al. 2020

A&A

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The MATLAS deep imaging survey has uncovered a plethora of dwarf galaxies in the low density environment it has mapped. A fraction of them are unusually extended and have low surface brightness. Among these so-called ultra-diffuse galaxies, a few seem to host an excess of globular clusters (GCs). With the integral field unit spectrograph MUSE we have observed one of these galaxies – MATLAS J15052031+0148447 (MATLAS-2019) – located toward the nearby group NGC 5846 and measured its systemic velocity, age, and metallicity, and that of its GC candidates. For the stellar body of MATLAS-2019 we derive a metallicity of −1.33−0.01+0.19 dex and an age of 11.2−0.8+1.8 Gyr. For some of the individual GCs and the stacked GC population, we derive consistent ages and metallicities. From the 11 confirmed GCs and using a Markov Chain Monte Carlo approach we derived a dynamical mass-to-light ratio of 4.2−3.4+8.6 M⊙/L⊙. This is at the lower end of the luminosity-mass scaling relation defined by the Local Group dwarf galaxies. Furthermore, we could not confirm or reject the possibility of a rotational component in the GC system. If present, this would further modify the inferred mass. Follow-up observations of the GC population and of the stellar body of the galaxy are needed to assess whether this galaxy lacks dark matter, as was suggested for the pair of dwarf galaxies in the field of NGC 1052, or if this is a misinterpretation arising from systematic uncertainties of the method commonly used for these systems and the large uncertainties of the individual GC velocities.

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Section: Discussionmentioning

confidence: 99%

Spectroscopic study of MATLAS-2019 with MUSE: An ultra-diffuse galaxy with an excess of old globular clusters

Müller

Marleau

Duc

et al. 2020

A&A

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“…The deep photometry allows us to trace the mass assembly in galaxies, by estimating the accreted mass fraction in the stellar halos, detecting the ICL and the stellar streams in the intra-cluster space, and providing results that can be directly compared with the predictions of galaxy formation models (Iodice et al 2016(Iodice et al , 2017bSpavone et al 2017aSpavone et al , 2018Cattapan et al 2019). Recently, in the deep imaging data of VEGAS for the NGC 5846 group of galaxies, we were able to detect an ultra diffuse galaxy, with an absolute magnitude of M g = −14.2 mag, corresponding to a stellar mass of ∼10 8 M (Forbes et al 2019).…”

Section: Introductionmentioning

confidence: 93%

VEGAS: a VST Early-type GAlaxy Survey

Iodice

Spavone

Cattapan

et al. 2020

A&A

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Context. This paper is based on the multi-band VST Early-type GAlaxy Survey (VEGAS) with the VLT Survey Telescope (VST). We present new deep photometry of the IC 1459 group in g and r band. Aims. The main goal of this work is to investigate the photometric properties of the IC 1459 group, and to compare our results with those obtained for other galaxy groups studied in VEGAS, in order to provide an initial view of the variation of their properties as a function of the evolution of the system. Methods. For all galaxies in the IC 1459 group, we fit isophotes and extract the azimuthally averaged surface-brightness profiles, the position angle, and ellipticity profiles as a function of the semi-major axis. We also extract the average colour profile. In each band, we estimate the total magnitude, effective radius, mean colour, and total stellar mass for each galaxy in the group. We then look at the structure of the brightest galaxies and the faint features in their outskirts, considering also the intragroup component. Results. The wide field of view, long integration time, high angular resolution, and arcsec-level seeing of OmegaCAM at VST allow us to map the light distribution of IC 1459 down to a surface brightness level of 29.26 mag arcsec−2 in g band and 28.85 mag arcsec−2 in r band, and out to 7−10Re, and to detect the optical counterpart of HI gas around IC 1459. We also carry out an in-depth exploration of three low-density environments and provide information to understand how galaxy and group properties change with the group evolution stage. Conclusions. Good agreement is found between our results and predictions of numerical simulations regarding the structural properties of the brightest galaxies of the groups. We suggest that the structure of the outer envelope of he brightest cluster galaxies (i.e. the signatures of past mergers and tidal interactions), the intra-group light, and the HI amount and distribution may be used as indicators of the evolutionary stage and mass assembly of galaxy groups.

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“…The dynamical understanding of UDGs is at a very early stage, however. There are perhaps a dozen, but more properly half a dozen UDGs, fully investigated kinematically (e.g., Forbes et al, 2019;van Dokkum et al, 2019). It is apparent that in the projection of the FP (Faber-Jackson or Tully-Fisher 9 ) UDGs are overluminous (Pina et al, 2019) for their dynamical parameter (σ or rotation) and that this can arise simply from their deviation in surface brightness, the virial theorem referenced to the surface brightness law of normal galaxies, Equation (5) of Aaronson et al (1979)…”

Section: The Tully Fisher Relationmentioning

confidence: 99%

Understanding the Fundamental Plane and the Tully Fisher Relation

Mould¹

2020

Front. Astron. Space Sci.

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The relation between early type galaxy size, surface brightness and velocity dispersion, "the fundamental plane," has long been understood as resulting from equilibrium in their largely pressure supported stellar dynamics. The dissipation and feedback involved in reaching such an equilibrium through merger formation of these galaxies over cosmic time can be responsible for the orientation of the plane. We see a correlation between surface brightness enhancement and youth in the 6dF Galaxy Survey. Correlations of this "tilt" with stellar mass, age, concentration, shape, and metallicity now point the direction for further work on the resolved kinematics and structure of these nearby galaxies and on their initial mass function and dark matter component. On the face of it, the Tully Fisher relation is a simpler one dimensional scaling relation. However, as late type galaxies have bulges as well as disks, and, as the surface density of disks is only standard for the more massive galaxies, additional parameters are involved.

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An ultra diffuse galaxy in the NGC 5846 group from the VEGAS survey

Cited by 45 publications

References 32 publications

Spectroscopic study of MATLAS-2019 with MUSE: An ultra-diffuse galaxy with an excess of old globular clusters

Spectroscopic study of MATLAS-2019 with MUSE: An ultra-diffuse galaxy with an excess of old globular clusters

VEGAS: a VST Early-type GAlaxy Survey

Understanding the Fundamental Plane and the Tully Fisher Relation

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