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We present stellar and dark matter (DM) density profiles for a sample of seven massive, relaxed galaxy clusters derived from strong and weak gravitational lensing and resolved stellar kinematic observations within the centrally-located…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Andrew B. Newman , Tommaso Treu , Richard S. Ellis , David J. Sand

We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs…

Astrophysics of Galaxies · Physics 2015-06-22 Silvia Posacki , Michele Cappellari , Tommaso Treu , Silvia Pellegrini , Luca Ciotti

We have undertaken the largest systematic study of the high-mass stellar initial mass function (IMF) to date using the optical color-magnitude diagrams (CMDs) of 85 resolved, young (4 Myr < t < 25 Myr), intermediate mass star clusters…

We investigate the viability of a simple dark matter (DM) model consisting of a single fermion in the context of galactic dynamics. We use a consistent approach that does not presume a particular DM density profile but instead requires that…

Astrophysics of Galaxies · Physics 2019-10-16 K. Pal , L. V. Sales , J. Wudka

We show that Milky Way white dwarfs are excellent targets for dark matter (DM) detection. Using Fermi and H.E.S.S. Galactic center gamma-ray data, we investigate sensitivity to DM annihilating within white dwarfs into long-lived or boosted…

High Energy Physics - Phenomenology · Physics 2024-06-05 Javier F. Acevedo , Rebecca K. Leane , Lillian Santos-Olmsted

Gravitational potential fluctuations driven by bursty star formation can kinematically 'heat up' dark matter at the centres of dwarf galaxies. A key prediction of such models is that, at a fixed dark matter halo mass, dwarfs with a higher…

Astrophysics of Galaxies · Physics 2019-04-15 J. I. Read , M. G. Walker , P. Steger

The recently inferred variations in the stellar initial mass function (IMF) among local high-mass early-type galaxies may require a reinterpretation of observations of galaxy populations and may have important consequences for the…

Astrophysics of Galaxies · Physics 2018-07-17 Christopher Barber , Robert A. Crain , Joop Schaye

We present radially resolved spectroscopy of 8 early-type galaxies in Abell~262, measuring rotation, velocity dispersion, $H_3$ and $H_4$ coefficients along three axes, and line-strength index profiles of Mg, Fe and H$\beta$. Ionized-gas…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 G. A. Wegner , E. M. Corsini , J. Thomas , R. P. Saglia , R. Bender , S. B. Pu

We present a detailed analysis of the effect of an observationally determined dark matter (DM) velocity distribution function (VDF) of the Milky Way (MW) on DM direct detection rates. We go beyond local kinematic tracers and use rotation…

High Energy Physics - Phenomenology · Physics 2019-07-17 Sayan Mandal , Subhabrata Majumdar , Vikram Rentala , Ritoban Basu Thakur

Variations in the stellar initial mass function (IMF) have been invoked to explain the spectroscopic and dynamical properties of early-type galaxies. However, no observations have yet been able to disentangle the physical driver. We analyse…

Recent work has suggested that the stellar initial mass function (IMF) is not universal, but rather is correlated with galaxy stellar mass, stellar velocity dispersion, or morphological type. In this paper, we investigate variations of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 A. A. Dutton , T. Treu , B. J. Brewer , P. J. Marshall , M. W. Auger , M. Barnabe , D. C. Koo , A. S. Bolton , L. V. E. Koopmans

It has been shown recently that the dynamical V-band mass-to-light ratios of compact stellar systems with masses from 10^6 to 10^8 Solar masses are not consistent with the predictions from simple stellar population (SSP) models. Top-heavy…

Astrophysics of Galaxies · Physics 2010-02-25 J. Dabringhausen , P. Kroupa , H. Baumgardt

We study the dark matter (DM) assembly in the central regions of massive early-type galaxies up to $z\sim 0.65$. We use a sample of $\sim 3800$ massive ($\log M_{\rm \star}/M_{\rm \odot} > 11.2$) galaxies with photometry and structural…

Astrophysics of Galaxies · Physics 2017-11-08 C. Tortora , N. R. Napolitano , N. Roy , M. Radovich , F. Getman , L. V. E. Koopmans , G. A. Verdoes Kleijn , K. H. Kuijken

The stellar initial mass function (IMF), which is often assumed to be universal across unresolved stellar populations, has recently been suggested to be "bottom-heavy" for massive ellipticals. In these galaxies, the prevalence of…

In the cosmological paradigm, cold dark matter (DM) dominates the mass content of the Universe and is present at every scale. Candidates for DM include many extensions of the standard model, such as weakly interacting massive particles…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Benjamin Zitzer

It has frequently been suggested that the stellar IMF in galaxies was top-heavy at early times. This would be plausible physically if the IMF depends on a mass scale such as the Jeans mass that was higher at earlier times because of the…

Astrophysics · Physics 2009-10-30 Richard B. Larson

We study the behavior of the dynamical and stellar mass inside the effective radius of early-type galaxies (ETGs) as a function of environment considering Newtonian dynamics, different surface--brightness profiles, different initial mass…

In this work, we want to find out if the IMF can be determined from colour images, integrated colours, or mass-to-light ratios, especially at high redshift, where galaxies cannot be resolved into individual stars, which would enable us to…

Astrophysics · Physics 2008-11-26 P. Westera , M. Samland , S. J. Kautsch , R. Buser , K. Ammon

[abridged] Recently, in Benetti et al. (Astrophys. J. 2023, 949, 65), we suggested that the dark matter (DM) component in galaxies may originate fractional gravity. In such a framework, the DM component exists, but the gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-11 Francesco Benetti , Andrea Lapi , Giovanni Gandolfi , Balakrishna S. Haridasu , Luigi Danese

The extragalactic dark matter (DM) annihilation signal depends on the product of the clumping factor, <\delta^2>, and the velocity-weighted annihilation cross section, \sigma v. This "clumping factor-\sigma v" degeneracy can be broken by…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-18 Kenny C. Y. Ng , Ranjan Laha , Sheldon Campbell , Shunsaku Horiuchi , Basudeb Dasgupta , Kohta Murase , John F. Beacom