The SLUGGS survey: a comparison of total-mass profiles of early-type galaxies from observations and cosmological simulations, to ∼4 effective radii

Bellstedt, Sabine; Forbes, Duncan A.; Romanowsky, Aaron J.; Remus, Rhea-Silvia; Stevens, Adam; Brodie, Jean P.; Poci, Adriano; McDermid, Richard M.; Alabi, Adebusola B.; Chevalier, Leonie; Adams, Caitlin; Ferré-Mateu, Anna; Wasserman, Asher; Pandya, Viraj

doi:10.1093/mnras/sty456

Cited by 52 publications

(69 citation statements)

References 124 publications

(218 reference statements)

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“…It declines with decreasing distance and increasing mass because the external field of NGC 1052 suppresses MONDian self-gravity leading to Newtonian behaviour in the case when a i a e . For the nominal host mass M NGC1052 = 10 11 M(Bellstedt et al 2018) and if D = 98 kpc, the MOND velocity dispersion is in agreement within the 2-sigma confidence range of the here measured value. Black lines show the simulated N-MODY line-of-sight velocity dispersion of DF2 as a function of D sep for different orbits with different pericentre velocities.…”

supporting

confidence: 84%

A new formulation of the external field effect in MOND and numerical simulations of ultra-diffuse dwarf galaxies – application to NGC 1052-DF2 and NGC 1052-DF4

Haghi

Kroupa

Banik

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The ultra-diffuse dwarf galaxy NGC 1052-DF2 (DF2) has ten (eleven) measured globular clusters (GCs) with a line-of-sight velocity dispersion of σ = 7.8 +5.2 −2.2 km/s (σ = 10.6 +3.9 −2.3 km/s). Our conventional statistical analysis of the original ten GCs gives σ = 8.0 +4.3 −3.0 km/s. The overall distribution of velocities agrees well with a Gaussian of this width. Due to the non-linear Poisson equation in MOND, a dwarf galaxy has weaker self-gravity when in close proximity to a massive host. This external field effect is investigated using a new analytic formulation and fully self-consistent live N-body models in MOND. Our formulation agrees well with that of Famaey and McGaugh (2012). These new simulations confirm our analytic results and suggest that DF2 may be in a deep-freeze state unique to MOND. The correctly calculated MOND velocity dispersion agrees with our inferred dispersion and that of van Dokkum et al. (2018b) if DF2 is within 150 kpc of NGC 1052 and both are 20 Mpc away. The GCs of DF2 are however significantly brighter and larger than normal GCs, a problem which disappears if DF2 is significantly closer to us. A distance of 10-13 Mpc makes DF2 a normal dwarf galaxy even more consistent with MOND and the 13 Mpc distance reported by Trujillo et. al. (2019). We discuss the similar dwarf DF4, finding good agreement with MOND. We also discuss possible massive galaxies near DF2 and DF4 along with their distances and peculiar velocities, noting that NGC 1052 may lie at a distance near 10 Mpc.

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supporting

confidence: 84%

A new formulation of the external field effect in MOND and numerical simulations of ultra-diffuse dwarf galaxies – application to NGC 1052-DF2 and NGC 1052-DF4

Haghi

Kroupa

Banik

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The 'main progenitor branch' of the merger tree for a galaxy is determined by the sublink algorithm which follows the subhalo branch with the 'most massive history' (De Lucia & Blaizot 2007). We will also identify mergers through the merger tree, since the assembly of the ex-situ formed stellar population is dominated by major and minor mergers (Rodriguez-Gomez et al 2016), and correlates with the total power-law slope (Remus et al 2017;Bellstedt et al 2018). Following the approach of Rodriguez-Gomez et al (2015), all galaxy properties of the in-falling galaxy that merged into the main progenitors will be calculated at the snapshot in which it had the largest value of stellar mass enclosed within twice its stellar half mass radius.…”

Section: The Sublink Merger Treementioning

confidence: 99%

“…Especially for the baryon dominated inner region, γ serves as an indicator of the compactness of the matter distribution within a few effective radii. It is well known from observations of strong and weak lensing of high-redshift ETGs (Koopmans et al 2006;Gavazzi et al 2007;Koopmans et al 2009;Barnabè et al 2009Barnabè et al , 2011Auger et al 2010;Li et al 2018;Lyskova et al 2018), X-ray studies (Humphrey et al 2006;Humphrey & Buote 2010) and local dynamically modeled ETGs (Tortora et al 2014a;Cappellari et al 2015;Serra et al 2016;Poci et al 2017;Bellstedt et al 2018) that the power-law slope γ is close to 2, resembling a self-gravitating isothermal collisional ideal gas sphere. Since neither the stellar nor the dark matter component follow such a density profile, this combined effect is also known as the 'bulge-halo conspiracy'.…”

Section: Introductionmentioning

confidence: 99%

Early-type galaxy density profiles from IllustrisTNG – II. Evolutionary trend of the total density profile

Wang

Vogelsberger

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We study the evolutionary trend of the total density profile of early-type galaxies (ETGs) in IllustrisTNG. To this end, we trace ETGs from z = 0 to z = 4 and measure the power-law slope γ of the total density profile for their main progenitors. We find that their γ steepen on average during z ∼ 4 − 2, then becoming shallower until z = 1, after which they remain almost constant, aside from a residual trend of becoming shallower towards z = 0. We also compare to a statistical sample of ETGs at different redshifts, selected based on their luminosity profiles and stellar masses. Due to different selection effects, the average slopes of the statistical samples follow a modified evolutionary trend. They monotonically decrease since z = 3, and after z ≈ 1, they remain nearly invariant with a mild increase towards z = 0. These evolutionary trends are mass-dependent for both samples, with low-mass galaxies having in general steeper slopes than their more massive counterparts. Galaxies that transitioned to ETGs more recently have steeper mean slopes as they tend to be smaller and more compact at any given redshift. By analyzing the impact of mergers and AGN feedback on the progenitors' evolution, we conjecture a multi-phase path leading to isothermality in ETGs: dissipation associated with rapid wet mergers tends to steepen γ from z = 4 to z = 2, whereas subsequent AGN feedback (especially in the kinetic mode) makes γ shallower again from z = 2 to z = 1. Afterwards, passive evolution from z = 1 to z = 0, mainly through gas-poor mergers, mildly decreases γ and maintains the overall mass distribution close to isothermal.

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“…Four slit-masks were obtained under seeing conditions of 0.6 to 1.3 arcsec. For observing details see Bellstedt et al (2018) who analysed the slits near the galaxy centre containing galaxy starlight. Here we use the slits dedicated to GC candidates of NGC 1052.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Dark matter and no dark matter: on the halo mass of NGC 1052

Forbes

Alabi

Brodie

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The NGC 1052 group, and in particular the discovery of two ultra diffuse galaxies with very low internal velocity dispersions, has been the subject of much attention recently. Here we present radial velocities for a sample of 77 globular clusters associated with NGC 1052 obtained on the Keck telescope. Their mean velocity and velocity dispersion are consistent with that of the host galaxy. Using a simple tracer mass estimator, we infer the enclosed dynamical mass and dark matter fraction of NGC 1052. Extrapolating our measurements with an NFW mass profile we infer a total halo mass of 6.2 (±0.2) × 10 12 M . This mass is fully consistent with that expected from the stellar mass-halo mass relation, suggesting that NGC 1052 has a normal dark matter halo mass (i.e. it is not deficient in dark matter in contrast to two ultra diffuse galaxies in the group). We present a phase space diagram showing the galaxies that lie within the projected virial radius (390 kpc) of NGC 1052. Finally, we briefly discuss the two dark matter deficient galaxies (NGC 1052-DF and DF4) and consider whether MOND can account for their low observed internal velocity dispersions.

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The SLUGGS survey: a comparison of total-mass profiles of early-type galaxies from observations and cosmological simulations, to ∼4 effective radii

Cited by 52 publications

References 124 publications

A new formulation of the external field effect in MOND and numerical simulations of ultra-diffuse dwarf galaxies – application to NGC 1052-DF2 and NGC 1052-DF4

A new formulation of the external field effect in MOND and numerical simulations of ultra-diffuse dwarf galaxies – application to NGC 1052-DF2 and NGC 1052-DF4

Early-type galaxy density profiles from IllustrisTNG – II. Evolutionary trend of the total density profile

Dark matter and no dark matter: on the halo mass of NGC 1052

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