A MegaCam Survey of Outer Halo Satellites. VII. A Single Sérsic Index versus Effective Radius Relation for Milky Way Outer Halo Satellites*

†

Marchi-Lasch, S.; Muñoz, Ricardo R.; Santana, Felipe A.; Carballo‐Bello, J. A.; Chanamé, Julio; Geha, Marla; Simon, Joshua D.; Stetson, P. B.; Djorgovski, S. G.

doi:10.3847/1538-4357/ab089c

Cited by 14 publications

(9 citation statements)

References 68 publications

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“…The structural parameters of the bulge of NGC 5474 are consistent with those of pseudo-bulges (Kormendy & Kennicutt 2004, Fisher & Drory 2008, and indeed it is classified as such by Fisher & Drory (2010). It is interesting to note that these parameters are also fully compatible with the scaling laws of dwarf galaxies (see, e.g., Côté et al 2008, Lange et al 2015, Bellazzini et al 2017, Marchi-Lasch et al 2019. In particular, the absolute integrated magnitude, the stellar mass, and the effective radius of the bulge are quite similar to those of NGC 205, a nucleated dwarf elliptical satellite of M 31 (M V = −16.5 ± 0.1, M = 3.3 × 10 8 M , assuming M/L V = 1.0, and R e = 445 ± 25 pc (circularised), from McConnachie 2012).…”

Section: Surface Photometrymentioning

confidence: 52%

The strange case of the peculiar spiral galaxy NGC 5474

Bellazzini¹,

Annibali²,

Tosi³

et al. 2020

A&A

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We present the first analysis of the stellar content of the structures and substructures identified in the peculiar star-forming galaxy NGC 5474, based on Hubble Space Telescope resolved photometry from the LEGUS survey. NGC 5474 is a satellite of the giant spiral M 101, and is known to have a prominent bulge that is significantly off-set from the kinematic center of the underlying H i and stellar disc. The youngest stars (age≤ 100 Myr) trace a flocculent spiral pattern extending out to > ∼ 8 kpc from the center of the galaxy. On the other hand intermediate-age (age > ∼ 500 Myr) and old (age ≥ 2 Gyr) stars dominate the off-centred bulge and a large substructure residing in the South Western part of the disc and not correlated with the spiral arms (SW over-density). The old age of the stars in the SW over-density suggests that this may be another signature of the dynamical interaction/s that have shaped this anomalous galaxy. We suggest that a fly by with M 101, generally invoked as the origin of the anomalies, may not be sufficient to explain all the observations. A more local and more recent interaction may help to put all the pieces of this galactic puzzle together.

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Section: Surface Photometrymentioning

confidence: 52%

The strange case of the peculiar spiral galaxy NGC 5474

Bellazzini¹,

Annibali²,

Tosi³

et al. 2020

A&A

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“…Here we consider all stellar systems as a single class aiming not to distinguish between globular clusters and dwarfs. Our moti v ation is two-fold: first, these systems have a similar range in stellar mass, and second, as pointed out by Marchi-Lasch et al ( 2019 ), there are similarities between structural properties of ultra faint dwarfs and low-surface brightness GCs. This leads us to distinguish three different populations, the high-surface brightness (HSB-GCs, with log (SB/ L pc −2 ) > 2), the low-surface brightness (LSB-GCs, with log (SB/ L pc −2 ) < 2) globular clusters (see Fig.…”

Section: Data a N D D E R I V E D O R B I Ta L Pa R A M E T E R Smentioning

confidence: 87%

The accretion history of the Milky Way – I. How it shapes globular clusters and dwarf galaxies

Hammer¹,

Mamon

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Halo inhabitants are individual stars, stellar streams, star, and globular clusters, and dwarf galaxies. Here we compare the two last categories that include objects of similar stellar mass, which are often studied as self-dynamical equilibrium systems. We discover that the half-light radius of globular clusters depends on their orbital pericentre and total energy, and that Milky Way (MW) tides may explain the observed correlation. We also suggest that the accretion epoch of stellar systems in the MW halo can be calibrated by the total orbital energy, and that such a relation is due to both the mass growth of the MW and dynamical friction affecting mostly satellites with numerous orbits. This calibration starts from the bulge to Kraken, Gaia Sausage Enceladus, Sagittarius stellar systems, and finally to the new coming dwarfs, either or not linked to the vast-polar structure. The most eccentric globular clusters, and dwarfs have their half-light radius scaling as the inverse of their binding energy, and this over more than two decades. This means that earlier arriving satellites are smaller due to the tidal effects of the MW. Therefore, most halo inhabitants appear to have their structural parameters shaped by MW tides, and also by ram-pressure for the most recent arrivals, the dwarf galaxies. The correlations found in this study can be used as tools to further investigate the origin of globular clusters and dwarfs, as well as the assembly history of our Galaxy.

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“…• For the MW satellites, we primarily use the homogeneous analysis from the Megacam Survey of Outer Halo Objects (Muñoz et al 2018a,b;Marchi-Lasch All three of these data sets were observed with CFHT/MegaCam. H21 and PAn-dAS used the g, i−bands and the MSOHO dataset used the g, r−bands (supplemented with some additional DECam observations in equivalent filters).…”

Section: Sample Definitionmentioning

confidence: 99%

Solo dwarfs IV: comparing and contrasting satellite and isolated dwarf galaxies in the Local Group

Higgs

McConnachie

2021

Monthly Notices of the Royal Astronomical Society

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We compare and contrast the stellar structures of isolated Local Group dwarf galaxies, as traced by their oldest stellar populations, with the satellite dwarf galaxies of the Milky Way and M 31. All Local Group dwarfs with Mv ≤ −6 and μo < 26.5 mags arcsec−2 are considered, taking advantage of measurements from surveys that use similar observations and analysis techniques. For the isolated dwarfs, we use the results from Solitary Local (Solo) Dwarf Galaxy Survey. We begin by confirming that the structural and dynamical properties of the two satellite populations are not obviously statistically different from each other, but we note that there many more satellites around M 31 than around the Milky Way down to equivalent magnitude and surface brightness limits. We find that dwarfs in close proximity to a massive galaxy generally show more scatter in their Kormendy relations than those in isolation. Specifically, isolated Local Group dwarf galaxies show a tighter trend of half-light radius versus magnitude than the satellite populations, and similar effects are also seen for related parameters. There appears to be a transition in the structural and dynamical properties of the dwarf galaxy population around ∼400 kpc from the Milky Way and M 31, such that the smallest, faintest, most circular dwarf galaxies are found closer than this separation. We discuss the impact of selection effects on our analysis, and we argue that our results point to the significance of tidal interactions on the population of systems within approximately 400 kpc from the MW and M 31.

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A MegaCam Survey of Outer Halo Satellites. VII. A Single Sérsic Index versus Effective Radius Relation for Milky Way Outer Halo Satellites* †

Cited by 14 publications

References 68 publications

The strange case of the peculiar spiral galaxy NGC 5474

The strange case of the peculiar spiral galaxy NGC 5474

The accretion history of the Milky Way – I. How it shapes globular clusters and dwarf galaxies

Solo dwarfs IV: comparing and contrasting satellite and isolated dwarf galaxies in the Local Group

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