An Enigmatic Population of Luminous Globular Clusters in a Galaxy Lacking Dark Matter

Dokkum, Pieter van; Cohen, Yotam; Danieli, Shany; Kruijssen, J. M. Diederik; Romanowsky, Aaron J.; Merritt, Allison; Abraham, Roberto; Brodie, Jean P.; Conroy, Charlie; Lokhorst, Deborah; Mowla, Lamiya; O’Sullivan, Ewan; Zhang, Jielai

doi:10.3847/2041-8213/aab60b

Cited by 101 publications

(170 citation statements)

References 48 publications

Supporting

Mentioning

155

Contrasting

Order By: Relevance

“…We will show that the dynamics of DF44 can be explained in the MOND alternative to dark matter using an acceptable stellar M/L I ratio without making further ad hoc modifications to MOND. The difference between our conclusions and those of Hodson & Zhao (2017) arise mainly from a subsequent downwards revision to σ los (van Dokkum et al 2019b).…”

Section: Introductioncontrasting

confidence: 98%

“…This is de-termined by combining photometric observations of L I with the chosen or fitted stellar mass-to-light ratio M/L I . To assess how DF44 should behave in MOND, we can apply the deep-MOND virial relation (Milgrom 1995) to estimate that its globally averaged one-dimensional velocity dispersion should be 4 4GM a 0 /81 = 22 km/s for an I-band luminosity of 3 × 10 8 L I (van Dokkum et al 2019b) and a stellar mass to light ratio of 1 Solar unit in this band (Sec. 2).…”

Section: Milgromian Dynamics (Mond)mentioning

confidence: 99%

“…van Dokkum et al (2018) and van Dokkum et al (2019a) previously reported the discovery of two 'dark matter-free' UDGs, NGC 1052-DF2 (DF2) and NGC 1052-DF4 (DF4), with line-of-sight velocity dispersions of σ los = 8.5 +2.2 −3.1 km/s (Danieli et al 2019) and σ los = 4.2 +4.4 −2.2 km/s (van Dokkum et al 2019b), respectively. In both cases, the upper limit to the halo mass is M 200 10 8 M (van Dokkum et al 2018(van Dokkum et al , 2019aWasserman et al 2018). They argue that the apparent lack of dark matter in DF2 and DF4 is in contrast to Dragonfly 44 (DF44), which is gravitationally dominated by dark matter (van Dokkum et al 2016).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

Haghi

Amiri

Zonoozi

et al. 2019

ApJL

View full text Add to dashboard Cite

The observed line-of-sight velocity dispersion σ los of the ultra diffuse galaxy Dragonfly 44 (DF44) requires a Newtonian dynamical mass-to-light ratio of M dyn /L I = 26 +7 −6 Solar units. This is well outside the acceptable limits of our stellar population synthesis (SPS) models, which we construct using the integrated galactic initial mass function (IGIMF) theory. Assuming DF44 is in isolation and using Jeans analysis, we calculate σ los profiles of DF44 in Milgromian dynamics (MOND) and modified gravity (MOG) theories without invoking dark matter. Comparing with the observed kinematics, the best-fitting MOND model has M dyn /L I = 3.6 +1.6 −1.2 and a constant orbital anisotropy of β = −0.5 +0.4 −1.6 . In MOG, we first fix its two theoretical parameters α and µ based on previous fits to the observed rotation curve data of The HI Nearby Galaxy Survey (THINGS). The DF44 σ los profile is best fit with M dyn /L I = 7.4 +1.5 −1.4 , larger than plausible SPS values. MOG produces a σ los profile for DF44 with acceptable M dyn /L I and isotropic orbits if α and µ are allowed to vary. MOND with the canonical a 0 can explain DF44 at the 2.40σ confidence level (1.66%) if considering both its observed kinematics and typical star formation histories in an IGIMF context. However, MOG is ruled out at 5.49σ (P -value of 4.07 × 10 −8 ) if its free parameters are fixed at the highest values consistent with THINGS data.

show abstract

Section: Introductioncontrasting

confidence: 98%

Section: Milgromian Dynamics (Mond)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

Haghi

Amiri

Zonoozi

et al. 2019

ApJL

View full text Add to dashboard Cite

show abstract

“…Apparently, we can talk about the synchronized gravitational field that connects all objects of the galaxy's system. The team of authors (van Dokkum et al ) recently published velocity measurements of luminous globular clusters in the galaxy NGC 1052-DF2, concluding that it lies far off the canonical stellar mass-halo mass (SMHM) relation [71][72][73]. They report that they have discovered a galaxy in which dark matter is almost completely absent.…”

Section: General Characteristics Of the Models Attempt To Reconcilementioning

confidence: 99%

The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological ‘Coupling Constants’ in the Theory of Induced Gravity

Zaripov¹

2019

Symmetry

View full text Add to dashboard Cite

This work is the extension of author's research, where the modified theory of induced gravity (MTIG) is proposed. The theory describes two systems (stages): Einstein (ES) and "restructuring" (RS). We consider equations with quadratic potential that are symmetric with respect to scale transformations. The solutions of the equations obtained for the case of spaces defined by the Friedman-Robertson-Walker metric, as well as for a centrally symmetric space are investigated. In our model arise effective gravitational and cosmological "constants" , which are defined by the "mean square" of the scalar fields. In obtained solutions the values of such parameters as "Hubble parameter", gravitational and cosmological "constants" in the RS stage fluctuate near monotonically evolving mean values. These parameters are matched with observational data, described as phenomena of dark energy and dark matter. The MTIG equations for the case of a centrally symmetric gravitational field, in addition to the Schwarzschild-de Sitter solutions, contain solutions that lead to the new physical effects at large distances from the center. The Schwarzschild-Sitter solution becomes unstable and enters the oscillatory regime. For distances greater than a certain critical value, the following effects can appear: deviation from General relativity and Newton's law of gravitational interaction, antigravity. Telescope (HST) and Planck observatory [5]. The Hubble Space Telescope is tuned to measure the parallax Milky Way Cepheid variables and the distances are 1.7-3.6 kpc (the modern Universe). The measurements of the Planck spacecraft correspond to distant galaxies (the early Universe is about 375,000 years old). In 2018, the accuracy of the measurement of H 0 is increased to 2.3 percent, which gives H 0 = 73.48 ± 1.66 km · s −1 Mpc −1 . In the early Universe, based on the data received from the "Planck" spacecraft and ΛCDM theory, the predicted value is H 0 = 67.0 ± 1.2 km · s −1 Mpc −1 . The difference is about 9 percent. The accuracy of the measurements is about 4.5 percent. There is also a variance in the observations made at different times and different methods. For example, as indicated in the work [6], the local and direct definition of H 0 gives H 0 = 73.24 ± 1.74 km · s −1 Mpc −1 , and the most recent value from [7] in consent with ΛCDM is 66.93 ± 0.62 km · s −1 Mpc −1 . In our opinion, the problem can be reduced to a strong binding of calculations of the Hubble parameter H 0 to the ΛCDM model. In our work we present a model where, due to the oscillatory regime in the solutions of equations, the Hubble parameter also fluctuates with respect to the mean value-which is also a function of time.3. The problems of so-called "dark energy" (DE) and "dark matter" (DM). The first of them can be reduced to the problem of existence and smallness of the "cosmological constant" (par. 1). The challenge posed by the cosmological constant problem [1] has spurred many attempts at directly modifying Einstein's gravity at large distances [8]. As example of s...

show abstract

“…Their unusually large half-light radii, R e ≥ 1.5 kpc, for galaxies with such low central surface brightness, µ 0,g ≥ 24 mag arcsec −2 , are striking. Although large LSB galaxies have been known for quite some time (Disney 1976;Sandage & Binggeli 1984;Impey et al 1988;Schombert & Bothun 1988;Schwartzenberg et al 1995;Dalcanton et al 1997;Sprayberry et al 1997), the current excitement originates from indications, either from kinematic measures of the unresolved light or globular clusters in these galaxies Toloba et al 2018;van Dokkum et al 2019), or from the numbers of globular clusters alone Beasley & Trujillo 2016;van Dokkum et al 2017van Dokkum et al , 2018a, that at least some UDGs lie in massive (> 10 11 M ) halos.…”

Section: Introductionmentioning

confidence: 99%

One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field

Barbosa

Zaritsky

Donnerstein

et al. 2020

ApJS

View full text Add to dashboard Cite

We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities and stellar masses of 100 UDGs distributed in an area of ∼ 330 deg 2 in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosityweighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population 2 Barbosa et al.scaling relations that show that UDGs are, as a population, similar to other low-surface brightness galaxies.

show abstract

An Enigmatic Population of Luminous Globular Clusters in a Galaxy Lacking Dark Matter

Cited by 101 publications

References 48 publications

The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological ‘Coupling Constants’ in the Theory of Induced Gravity

One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field

Contact Info

Product

Resources

About