Decoding Galactic Merger Histories

Bell, Eric F.; Monachesi, Antonela; D’Souza, Richard; Harmsen, Benjamin; Jong, Roelof S. de; Radburn-Smith, David J.; Bailin, Jeremy; Holwerda, Benne W.

doi:10.3390/galaxies5040095

Cited by 3 publications

(2 citation statements)

References 49 publications

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“…The stellar halo of M101 follows this correlation, extending the low mass end. This correlation is broadly consistent with expectations in cosmological simulations that most of the halo mass is accreted from the few most-massive progenitors (Vogelsberger et al 2014;Deason et al 2016;Bell et al 2017;D'Souza & Bell 2018). The low stellar halo mass and halo metallicity of M101 together with the MW indicate that these two galaxies had amongst the quietest accretion histories in the Local Universe.…”

Section: Comparison Of the M101 Stellar Halo With Other Observed Stel...supporting

confidence: 89%

Tracing the anemic stellar halo of M 101

Jang

Jong

Holwerda

et al. 2020

A&A

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Models of galaxy formation in a cosmological context predict that massive disk galaxies should have structured extended stellar halos. Recent studies in integrated light, however, report that a few galaxies, including the nearby disk galaxy M 101, have no measurable stellar halos to the detection limit. We aim to quantify the stellar content and structure of M 101’s outskirts by resolving its stars. We present the photometry of its stars based on deep F606W and F814W images taken with Hubble Space Telescope (HST) as part of the GHOSTS survey. The HST fields are placed along the east and west sides of M 101 out to galactocentric distance (R) of ∼70 kpc. The constructed color-magnitude diagrams of stars reach down to two magnitudes below the tip of the red giant branch. We derived radial number density profiles of the bright red giant branch (RGB) stars. The mean color of the RGB stars at R ∼ 40−60 kpc is similar to those of metal-poor globular clusters in the Milky Way. We also derived radial surface brightness profiles using the public image data provided by the Dragonfly team. Both the radial number density and surface brightness profiles were converted to radial mass density profiles and combined. We find that the mass density profiles show a weak upturn at the very outer region, where surface brightness is as faint as μg ≈ 33 mag arcsec−2. An exponential disk + power-law halo model on the mass density profiles finds the total stellar halo mass of Mhalo = 8.2−2.2+3.5 × 107 M⊙. The total stellar halo mass does not exceed Mhalo = 3.2 × 108 M⊙ when strongly truncated disk models are considered. In combining the halo mass with the total stellar mass of M 101, we obtain the stellar halo mass fraction of Mhalo/Mgal = 0.20−0.08+0.10% with an upper limit of 0.78%. We compare the halo properties of M 101 with those of six GHOSTS survey galaxies as well as the Milky Way and M 31 and find that M 101 has an anemic stellar halo similar to the Milky Way.

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Section: Comparison Of the M101 Stellar Halo With Other Observed Stel...supporting

confidence: 89%

Tracing the anemic stellar halo of M 101

Jang

Jong

Holwerda

et al. 2020

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, discerning between these two types of GC populations within a galaxy, can aid us to unveil the history of accretion and baryionic processes in galaxies (e.g. Bell et al 2017;Oman et al 2017;Youakim et al 2020).…”

Section: Introductionmentioning

confidence: 99%

The Escape of Globular Clusters from the Satellite Dwarf Galaxies of the Milky Way

Shirazi,

Haghi,

Khalaj

et al. 2022

Preprint

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Using numerical simulations, we have studied the escape of globular clusters (GCs) from the satellite dwarf spheroidal galaxies (dSphs) of the Milky Way (MW). We start by following the orbits of a large sample of GCs around dSphs in the presence of the MW potential field. We then obtain the fraction of GCs leaving their host dSphs within a Hubble Time. We model dSphs by a Hernquist density profile with masses between 10 7 M and 7 × 10 9 M . All dSphs lie on the Galactic disc plane, but they have different orbital eccentricities and apogalactic distances. We compute the escape fraction of GCs from 13 of the most massive dSphs of the MW, using their realistic orbits around the MW (as determined by Gaia). The escape fraction of GCs from 13 dSphs is in the range 12% to 93%. The average escape time of GCs from these dSphs was less than 8 Gyrs, indicating that the escape process of GCs from dSphs was over. We then adopt a set of observationally-constrained density profiles for specific case of the Fornax dSph. According to our results, the escape fraction of GCs shows a negative correlation with both the mass and the apogalactic distance of the dSphs, as well as a positive correlation with the orbital eccentricity of dSphs. In particular, we find that the escape fraction of GCs from the Fornax dSph is between 13% and 38%. Finally, we observe that when GCs leave their host dSphs, their final orbit around the MW does not differ much from their host dSphs.

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The escape of globular clusters from the satellite dwarf galaxies of the Milky Way

Rostami Shirazi,

Haghi,

Khalaj

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Using numerical simulations, we have studied the escape of globular clusters (GCs) from the satellite dwarf spheroidal galaxies (dSphs) of the Milky Way (MW). We start by following the orbits of a large sample of GCs around dSphs in the presence of the MW potential field. We then obtain the fraction of GCs leaving their host dSphs within a Hubble Time. We model dSphs by a Hernquist density profile with masses between 107 M⊙ and 7 × 109 M⊙. All dSphs lie on the Galactic disc plane, but they have different orbital eccentricities and apogalactic distances. We compute the escape fraction of GCs from 13 of the most massive dSphs of the MW, using their realistic orbits around the MW (as determined by Gaia). The escape fraction of GCs from 13 dSphs is in the range $12{{\ \rm per\ cent}}$ to $93{{\ \rm per\ cent}}$. The average escape time of GCs from these dSphs was less than 8 Gyrs, indicating that the escape process of GCs from dSphs was over. We then adopt a set of observationally-constrained density profiles for specific case of the Fornax dSph. According to our results, the escape fraction of GCs shows a negative correlation with both the mass and the apogalactic distance of the dSphs, as well as a positive correlation with the orbital eccentricity of dSphs. In particular, we find that the escape fraction of GCs from the Fornax dSph is between $13{{\ \rm per\ cent}}$ and $38{{\ \rm per\ cent}}$. Finally, we observe that when GCs leave their host dSphs, their final orbit around the MW does not differ much from their host dSphs.

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Decoding Galactic Merger Histories

Cited by 3 publications

References 49 publications

Tracing the anemic stellar halo of M 101

Tracing the anemic stellar halo of M 101

The Escape of Globular Clusters from the Satellite Dwarf Galaxies of the Milky Way

The escape of globular clusters from the satellite dwarf galaxies of the Milky Way

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