Spatially Resolved Stellar Kinematics of the Ultra-diffuse Galaxy Dragonfly 44. II. Constraints on Fuzzy Dark Matter

Einstein’s theory of gravity, General Relativity, has been precisely tested on Solar System scales, but the long-range nature of gravity is still poorly constrained. The nearby strong gravitational lens ESO 325-G004 provides a laboratory to probe the weak-field regime of gravity and measure the spatial curvature generated per unit mass, γ. By reconstructing the observed light profile of the lensed arcs and the observed spatially resolved stellar kinematics with a single self-consistent model, we conclude that γ = 0.97 ± 0.09 at 68% confidence. Our result is consistent with the prediction of 1 from General Relativity and provides a strong extragalactic constraint on the weak-field metric of gravity.

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Mapping the dark matter of NGC 2974: Combination of stellar & cold gas kinematics

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319008287 ◽

2019 ◽

Vol 14 (S353) ◽

pp. 253-254

Author(s):

M. Yang ◽

L. Zhu ◽

A. Weijmans ◽

G. van de Ven ◽

N. F. Boardman ◽

...

Keyword(s):

Dark Matter ◽

New Method ◽

Stellar Kinematics ◽

Gas Kinematics ◽

Superposition Technique ◽

Cold Gas

AbstractWe present a new method to combine cold gas kinematics with the stellar kinematics modelled with the Schwarzschild orbit-superposition technique, and its application to the lenticular galaxy NGC 2974. The combination of stellar and cold gas kinematics significantly improves the constraints on the measured dark matter profile: assuming a generalised NFW halo profile, we find a cuspy inner halo slope for NGC 2974.

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Stellar Populations and Kinematics in Seyfert Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306005126 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 71-75 ◽

Cited By ~ 1

Author(s):

N. V. Asari ◽

L. R. Vega ◽

A. Garcia-Rissmann ◽

R. M. González Delgado ◽

T. Storchi-Bergmann ◽

...

Keyword(s):

Equivalent Width ◽

Correlation Method ◽

Seyfert Galaxies ◽

Population Synthesis ◽

Stellar Kinematics ◽

Spatially Resolved ◽

Fitting Method ◽

Stellar Velocity ◽

Velocity Dispersions ◽

Nuclear Signal

AbstractOur aim is to study the stellar kinematics in hosts of AGN. We do so by measuring nuclear stellar velocity dispersions (σ⋆). Our sample comprises spectra of 78 objects, 69 of which are Seyfert galaxies, in the region around the λλ8498.02, 8542.09, 8662.14 Calcium triplet (CaT). We investigate two methods to measure σ⋆: (1) the direct fitting method (DFM), which makes use of our stellar population synthesis code Starlight, and (2) the cross-correlation method (CCM), for which we use the fxcor package in IRAF. Both methods yield velocity dispersions consistent to within 19 km/s on-average. We have also measured the CaT equivalent width (WCaT) and the λ3933 CaII K equivalent width (WK) for the objects in our sample. Other studies have shown that WK is a powerful tracer of starbursts in Seyfert nuclei, so we check if WCaT can be used in the same way. We have also analysed a sub-sample of 34 spatially resolved objects with reasonably good off-nuclear signal-to-noise. We study the spatial variations of both σ⋆ and WCaT. We see no dilution in WCaT for composite starburst + Seyfert 2 galaxies, in contrast to the dilution in the WK (studied by other authors) for the same objects.

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Spatially resolved properties of galaxies with a kinematically distinct core

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038244 ◽

2021 ◽

Vol 647 ◽

pp. A181

Author(s):

Kiyoaki Christopher Omori ◽

Tsutomu T. Takeuchi

Keyword(s):

Star Formation ◽

Emission Line ◽

Stellar Population ◽

Main Body ◽

Stellar Kinematics ◽

Stellar Core ◽

Spatially Resolved ◽

Star Formation Histories ◽

Inside Out ◽

Detailed Picture

Aims. Interacting galaxies show unique irregularities in their kinematic structures. By investigating the spatially resolved kinematics and stellar population properties of galaxies that demonstrate irregularities, we can paint a detailed picture of the formation and evolutionary processes that took place during their lifetimes. Methods. In this work, we focused on galaxies with a specific kinematic irregularity: a kinematically distinct stellar core (KDC). In particular, we considered counter-rotating galaxies in which the core and main body of are rotating in opposite directions. We visually identified 11 MaNGA galaxies with a KDC from their stellar kinematics, and we investigated their spatially resolved stellar and gaseous kinematic properties, namely the two-dimensional stellar and gaseous velocity and velocity-dispersion (σ) maps. Additionally, we examined the stellar population properties, as well as spatially resolved recent star formation histories, using the Dn4000 and Hδ gradients. Results. The galaxies display multiple off-centred symmetrical peaks in the stellar σ maps. The gaseous velocity and σ maps display regular properties. The stellar population properties and their respective gradients show differing properties depending on the results of the spatially resolved emission line diagnostics of the galaxies, with some but not all galaxies showing inside-out quenching. The star formation histories also largely differ based on the spatially resolved emission line diagnostics, but most galaxies show indications of recent star formation either in their outskirts or core. Conclusions. We find a distinct difference in kinematic and stellar population properties in galaxies with a counter-rotating stellar core, which depends on its classification using spatially resolved emission line diagnostics.

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The SAMI Galaxy Survey: decomposed stellar kinematics of galaxy bulges and disks

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1330 ◽

2020 ◽

Vol 495 (4) ◽

pp. 4638-4658 ◽

Cited By ~ 2

Author(s):

Sree Oh ◽

Matthew Colless ◽

Stefania Barsanti ◽

Sarah Casura ◽

Luca Cortese ◽

...

Keyword(s):

Rotation Velocity ◽

Stellar Kinematics ◽

Spatially Resolved ◽

Integral Field Spectroscopy ◽

Spin Parameter ◽

Wide Range ◽

The Galaxy ◽

Kinematic Behaviour ◽

Disk Component ◽

Integral Field

ABSTRACT We investigate the stellar kinematics of the bulge and disk components in 826 galaxies with a wide range of morphology from the Sydney-AAO Multi-object Integral-field spectroscopy Galaxy Survey. The spatially resolved rotation velocity (V) and velocity dispersion (σ) of bulge and disk components have been simultaneously estimated using the penalized pixel fitting (ppxf) method with photometrically defined weights for the two components. We introduce a new subroutine of ppxf for dealing with degeneracy in the solutions. We show that the V and σ distributions in each galaxy can be reconstructed using the kinematics and weights of the bulge and disk components. The combination of two distinct components provides a consistent description of the major kinematic features of galaxies over a wide range of morphological types. We present Tully–Fisher and Faber–Jackson relations showing that the galaxy stellar mass scales with both V and σ for both components of all galaxy types. We find a tight Faber–Jackson relation even for the disk component. We show that the bulge and disk components are kinematically distinct: (1) the two components show scaling relations with similar slopes, but different intercepts; (2) the spin parameter λR indicates bulges are pressure-dominated systems and disks are supported by rotation; and (3) the bulge and disk components have, respectively, low and high values in intrinsic ellipticity. Our findings suggest that the relative contributions of the two components explain, at least to first order, the complex kinematic behaviour of galaxies.

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Survey of gravitationally-lensed objects in HSC imaging (SuGOHI)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935743 ◽

2019 ◽

Vol 630 ◽

pp. A71 ◽

Cited By ~ 13

Author(s):

Alessandro Sonnenfeld ◽

Anton T. Jaelani ◽

James Chan ◽

Anupreeta More ◽

Sherry H. Suyu ◽

...

Keyword(s):

Dark Matter ◽

Gravitational Lensing ◽

Mass Function ◽

Initial Mass Function ◽

Dark Matter Halo ◽

Open Problems ◽

Massive Galaxies ◽

Spatially Resolved ◽

Stellar Masses ◽

The Imf

Context. The determination of the stellar initial mass function (IMF) of massive galaxies is one of the open problems in cosmology. Strong gravitational lensing is one of the few methods that allow us to constrain the IMF outside of the Local Group. Aims. The goal of this study is to statistically constrain the distribution in the IMF mismatch parameter, defined as the ratio between the true stellar mass of a galaxy and that inferred assuming a reference IMF, of massive galaxies from the Baryon Oscillation Spectroscopic Survey (BOSS) constant mass (CMASS) sample. Methods. We took 23 strong lenses drawn from the CMASS sample, measured their Einstein radii and stellar masses using multi-band photometry from the Hyper Suprime-Cam survey, then fitted a model distribution for the IMF mismatch parameter and dark matter halo mass to the whole sample. We used a prior on halo mass from weak lensing measurements and accounted for strong lensing selection effects in our model. Results. Assuming a Navarro Frenk and White density profile for the dark matter distribution, we infer a value μIMF = −0.04 ± 0.11 for the average base-10 logarithm of the IMF mismatch parameter, defined with respect to a Chabrier IMF. A Salpeter IMF is in tension with our measurements. Conclusions. Our results are consistent with a scenario in which the region of massive galaxies where the IMF normalisation is significantly heavier than that of the Milky Way is much smaller than the scales 5 − 10 kpc probed by the Einstein radius of the lenses in our sample, as recent spatially-resolved studies of the IMF in massive galaxies suggest.

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Dust and the observed dark matter content of galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900183615 ◽

2004 ◽

Vol 220 ◽

pp. 343-344 ◽

Cited By ~ 1

Author(s):

Maarten Baes ◽

Herwig Dejonghe ◽

Jonathan I. Davies

Keyword(s):

Dark Matter ◽

Interstellar Dust ◽

Optical Rotation ◽

Elliptical Galaxies ◽

Matter Content ◽

Dark Matter Halo ◽

Stellar Kinematics ◽

The Galaxy ◽

Dust Attenuation ◽

Radiative Transfer Modeling

Using detailed Monte Carlo radiative transfer modeling, we examine the effects of absorption and scattering by interstellar dust on the observed kinematics of galaxies. Our modeling results have a direct impact on the derivation of the properties of dark matter haloes around both elliptical and spiral galaxies. We find that interstellar dust has a very significant effect on the observed stellar kinematics of elliptical galaxies, in the way that it mimics the presence of a dark matter halo. Taking dust into account in kinematical modeling procedures can reduce or even eliminate the need for dark matter at a few effective radii. Dust profoundly affects the optical rotation curve and stellar kinematics of edge-on disc galaxies. This effect, however, is significantly reduced when the galaxy is more than a few degrees from strictly edge-on. These results demonstrate that dust attenuation cannot be invoked as a possible mechanism to reconcile the discrepancies between the observed shallow slopes of LSB galaxy rotation curves and the dark matter cusps found in CDM cosmological simulations.

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Uncovering dwarf elliptical evolution through spatially resolved spectroscopy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318006725 ◽

2018 ◽

Vol 14 (S344) ◽

pp. 345-348

Author(s):

Samantha J. Penny ◽

Keyword(s):

Active Galactic Nuclei ◽

Dwarf Galaxies ◽

Galactic Nuclei ◽

Disk Galaxies ◽

Stellar Kinematics ◽

Spatially Resolved ◽

Stellar Component ◽

Nearby Galaxies ◽

Spatially Resolved Spectroscopy ◽

Gas Component

AbstractUsing spatially resolved spectroscopy from the SDSS-IV Mapping Nearby Galaxies at APO (MaNGA) survey, we identify 69 dwarf elliptical (dE) galaxies in the nearby Universe fainter than Mr = −19 (MB = −18), selected independently of morphology and environment. The majority exhibit coherent rotation in their stellar kinematics, consistent with an origin as morphologically transformed disk galaxies. Six galaxies in this dE sample appear to host Active Galactic Nuclei (AGN) that are likely preventing current star formation through maintenance mode feedback. The ionised gas component of these dEs is typically kinematically offset from the stellar component, suggesting the gas is either recently accreted or outflowing. We therefore demonstrate the potential of IFU spectroscopy for understanding the physical properties of dwarf galaxies in detail.

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