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

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.

scholarly journals Mapping the dark matter halo of early-type galaxy NGC 2974 through orbit-based models with combined stellar and cold gas kinematics

2019 ◽  
Vol 491 (3) ◽  
pp. 4221-4231 ◽  
Author(s):  
Meng Yang ◽  
Ling Zhu ◽  
Anne-Marie Weijmans ◽  
Glenn van de Ven ◽  
Nicholas Boardman ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dark Matter Halo ◽  
Dark Halo ◽  
Confidence Limits ◽  
Early Type ◽  
Stellar Kinematics ◽  
Stellar Orbits ◽  
Gas Kinematics ◽  
Early Type Galaxy ◽  
Cold Gas

ABSTRACT We present an orbit-based method of combining stellar and cold gas kinematics to constrain the dark matter profile of early-type galaxies. We apply this method to early-type galaxy NGC 2974, using Pan-STARRS imaging and SAURON stellar kinematics to model the stellar orbits, and introducing H i kinematics from VLA observation as a tracer of the gravitational potential. The introduction of the cold gas kinematics shows a significant effect on the confidence limits of especially the dark halo properties: we exclude more than $95{{\ \rm per\ cent}}$ of models within the 1σ confidence level of Schwarzschild modelling with only stellar kinematics, and reduce the relative uncertainty of the dark matter fraction significantly to $10{{\ \rm per\ cent}}$ within 5Re. Adopting a generalized Navarro–Frenk–White (NFW) dark matter profile, we measure a shallow cuspy inner slope of $0.6^{+0.2}_{-0.3}$ when including the cold gas kinematics in our model. We cannot constrain the inner slope with the stellar kinematics alone.

Galactic dynamics and DM profile of NGC1380 with ALMA and VLT/MUSE

2019 ◽  
Vol 14 (S353) ◽  
pp. 248-252
Author(s):  
Takafumi Tsukui ◽  
Satoru Iguchi ◽  
Kyoko Onishi
Keyword(s):  
Dark Matter ◽  
Galaxy Evolution ◽  
Neutral Hydrogen ◽  
Hydrogen Gas ◽  
Large Field ◽  
Molecular Gas ◽  
Early Type ◽  
Stellar Kinematics ◽  
Gas Kinematics ◽  
The Galaxy

AbstractIn order to understand the interaction between dark matter and baryonic matter in the galaxy evolution history, it is fundamental to constrain dark matter (DM) distribution in galaxies. However, it is difficult to constrain DM profile in the central region of early type galaxy because of the lack of extended neutral hydrogen gas and the degeneracy between dynamical stellar M/L and DM profile. To resolve this difficulty, we conducted combined analysis of ALMA cold molecular gas kinematics and MUSE stellar kinematics of early type fast rotator galaxy NGC1380. In addition, we used HST image to trace the stellar luminosity distribution. With the help of high resolution of ALMA image and large field of view of MUSE, we derived the central BH mass, stellar bulge, disk and DM profile.

scholarly journals Modeling dark haloes in early-type galaxies: stellar kinematics at large radii

2009 ◽  
Vol 5 (H15) ◽  
pp. 69-69 ◽  
Author(s):  
Anne-Marie Weijmans
Keyword(s):  
Dark Matter ◽  
Absorption Line ◽  
New Method ◽  
Dark Matter Halo ◽  
Early Type ◽  
Stellar Kinematics ◽  
Signal To Noise ◽  
Stellar Halo ◽  
Halo Population ◽  
Integral Field

We developed a new method to obtain absorption line spectra of early-type galaxies at large radii, using integral-field spectrography (IFS). By using the spectrograph as a 'photon-collector' and adding the signal of many individual spaxels together in one spectrum, we obtain sufficient signal-to-noise to measure both stellar kinematics and line strengths at large radii. These can be used to determine the properties of the dark matter halo, as well as the stellar halo population.

scholarly journals The Recent Evolution of Early-Type Galaxies as Seen in their Cold Gas

2014 ◽  
Vol 10 (S309) ◽  
pp. 47-52
Author(s):  
Lisa M. Young
Keyword(s):  
Star Formation History ◽  
Molecular Gas ◽  
Early Type ◽  
Stellar Kinematics ◽  
Ionized Gas ◽  
Gas Kinematics ◽  
Formation History ◽  
Galaxy Assembly ◽  
Early Type Galaxy ◽  
Cold Gas

AbstractI present an overview of new observations of atomic and molecular gas in early-type galaxies, focusing on the Atlas3D project. Our data on stellar kinematics, age and metallicity, and ionized gas kinematics allow us to place the cold gas into the broader context of early-type galaxy assembly and star formation history. The cold gas data also provide valuable constraints for numerical simulations of early-type galaxies.

scholarly journals Constraining scalar fields with stellar kinematics and collisional dark matter

2010 ◽  
Vol 2010 (11) ◽  
pp. 002-002 ◽  
Author(s):  
Pau Amaro-Seoane ◽  
Juan Barranco ◽  
Argelia Bernal ◽  
Luciano Rezzolla
Keyword(s):  
Dark Matter ◽  
Scalar Fields ◽  
Stellar Kinematics

scholarly journals Baryonic Dark Halos: a model with MACHOS and cold gas globules

1996 ◽  
Vol 171 ◽  
pp. 167-170
Author(s):  
Ortwin Gerhard ◽  
Joseph Silk
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Active Role ◽  
Galaxy Formation And Evolution ◽  
Substellar Objects ◽  
Formation And Evolution ◽  
Cold Gas

The dark matter in the halos of galaxies may well be baryonic, and much of the mass within them could be in the form of clusters of substellar objects within which are embedded cold gas globules. Such halos might play an active role in galaxy formation and evolution.

scholarly journals The Central Bar in M 94

1996 ◽  
Vol 171 ◽  
pp. 422-422
Author(s):  
C. Möllenhoff ◽  
M. Matthias ◽  
O.E. Gerhard
Keyword(s):  
Major Axis ◽  
Stellar Kinematics ◽  
Semi Major Axis ◽  
Ionized Gas ◽  
Model Calculations ◽  
Gas Kinematics ◽  
Closed Orbits ◽  
Total Light ◽  
Axis Length ◽  
Global And Local

Surface photometry in I, J, K of the oval disk galaxy M 94 (NGC 4736) reveal a weak central stellar bar of 0.7 kpc semi-major axis length, comprising ≈ 14% of the total light within 20″. By stellar kinematics the existence of a small spheroidal bulge with v/à ≈ 0.8 was discovered. The ionized gas (Hα) in this region shows global and local deviations from the stellar kinematics. Model calculations of closed orbits for the cold gas in the combined potential of bar, disk, and bulge predict large non-circular motions in equilibrium flow. However, these do not fit the observed gas kinematics; obviously hydrodynamical forces play a role in the central region of M 94.

scholarly journals Cold gas in dark matter halos and the formation of late-type galaxies

2005 ◽  
Vol 1 (C199) ◽  
pp. 205-212 ◽  
Author(s):  
H. J. Mo ◽  
Xiaohu Yang ◽  
Frank C. van den Bosch ◽  
Neal S. Katz
Keyword(s):  
Dark Matter ◽  
Dark Matter Halos ◽  
Late Type ◽  
Cold Gas

scholarly journals An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU observations

2018 ◽  
Vol 614 ◽  
pp. A94 ◽  
Author(s):  
Pedro K. Humire ◽  
Neil M. Nagar ◽  
Carolina Finlez ◽  
Verónica Firpo ◽  
Roy Slater ◽  
...  
Keyword(s):  
Galactic Disk ◽  
Position Angle ◽  
Morphological Type ◽  
Emission Lines ◽  
Stellar Kinematics ◽  
Mean Velocity ◽  
Gas Kinematics ◽  
Gaussian Fit ◽  
Kinematic Position ◽  
Integral Field Spectrograph

We present two-dimensional stellar and gaseous kinematics of the inner 0.7 × 1.2 kpc2 of the Seyfert 1.5 galaxy ESO 362-G18, derived from optical (4092–7338 Å) spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈170 pc and spectral resolution of 36 km s−1. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [O III] emission shows a fan-shaped extension of ≈10′′ to the SE. We detect the [O III] doublet, [N II] and Hα emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of ≈137° and is centred approximately on the continuum peak. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122° to 139°, projected velocity amplitudes of the order of 100 km s−1, and a mean velocity dispersion of 100 km s−1. A double-Gaussian fit to the [O III]λ5007 and Hα lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100–250 km s−1 higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 × 10−2 M⊙ yr−1 in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 × 10−2 M⊙ yr−1. The total ionized gas mass within ~84 pc of the nucleus is 3.3 × 105 M⊙; infall velocities of ~34 km s−1 in this gas would be required to feed both the outflow and SMBH accretion.

scholarly journals Inferring the dark matter velocity anisotropy to the cluster edge

2020 ◽  
Vol 500 (3) ◽  
pp. 3151-3161
Author(s):  
Jacob Svensmark ◽  
Steen H Hansen ◽  
Davide Martizzi ◽  
Ben Moore ◽  
Romaine Tessier
Keyword(s):  
Dark Matter ◽  
Numerical Simulations ◽  
Galaxy Cluster ◽  
Dynamical Property ◽  
Large Error ◽  
New Method ◽  
Bright Galaxy ◽  
X Ray ◽  
Velocity Anisotropy ◽  
Error Bars

ABSTRACT Dark matter (DM) dominates the properties of large cosmological structures such as galaxy clusters, and the mass profiles of the DM have been inferred for these equilibrated structures for years by using cluster X-ray surface brightnesses and temperatures. A new method has been proposed, which should allow us to infer a dynamical property of the DM, namely the velocity anisotropy. For the gas, a similar velocity anisotropy is zero due to frequent collisions; however, the collisionless nature of DM allows it to be non-trivial. Numerical simulations have for years found non-zero and radially varying DM velocity anisotropies. Here we employ the method proposed by Hansen & Piffaretti, and developed by Høst et al. to infer the DM velocity anisotropy in the bright galaxy cluster Perseus, to near five times the radii previously obtained. We find the DM velocity anisotropy to be consistent with the results of numerical simulations, however, still with large error bars. At half the virial radius, we find the DM velocity anisotropy to be non-zero at 1.7$\, \sigma$, lending support to the collisionless nature of DM.

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