scholarly journals Hα Kinematics of Tidal Tails in Interacting Systems: Projection Effects and Dark Matter in TDGs

2004 ◽  
Vol 217 ◽  
pp. 526-531
Author(s):  
Philippe Amram ◽  
Fréderic Bournaud ◽  
Pierre-Alain Duc
Keyword(s):  
Dark Matter ◽  
Dwarf Galaxies ◽  
Matter Content ◽  
Field Of View ◽  
Large Field ◽  
Ionized Gas ◽  
Tidal Tail ◽  
Fabry Perot ◽  
Interacting Systems ◽  
Tidal Tails

Several interacting systems exhibit at the tip of their long tidal tails massive condensations of atomic hydrogen, which may be the progenitors of Tidal Dwarf Galaxies. Because, quite often, these tails are observed edge-on, projection effects have been claimed to account for the large HI column densities measured there. Here we show that determining the velocity field all along the tidal features, one may disentangle projection effects along the line of view from real bound structures. Due to its large field of view, high spectral and 2D spatial resolutions, Fabry-Perot observations of the ionized gas are well adapted to detect a kinematical signature of either streaming motions along a bent tidal tail or of in-falling/rotating material associated with a forming TDG. Spectroscopic observations also allow to measure the dynamical masses of the TDGs that are already relaxed and check their dark matter content.

scholarly journals Mass Determination in the Late-Type Spiral NGC 5457

2004 ◽  
Vol 220 ◽  
pp. 321-322
Author(s):  
Ivânio Puerari ◽  
Margarita Valdez-Gutiérrez ◽  
Margarita Rosado
Keyword(s):  
Dark Matter ◽  
Hii Regions ◽  
Matter Content ◽  
Gas Content ◽  
Dynamical Analysis ◽  
Mass Determination ◽  
Late Type ◽  
Ionized Gas ◽  
Fabry Perot ◽  
Insight Into

We have performed a kinematical and dynamical analysis of the ionized gas content of the late–type spiral NGC 5457 (M101) by means of scanning Fabry–Perot interferometry. the purpose of this study is to gain insight into the dark matter content in this galaxy. A sample of 263 HII regions were catalogued. We calculated radial velocity and velocity dispersions. From the dynamics of the ionized gas we were able to infer a mass of 9.8 × 1010 M⊙ inside a radius of 4'8 (or 10 kpc).

scholarly journals Tidal dwarf galaxies as laboratories of star formation and cosmology

2006 ◽  
Vol 2 (S237) ◽  
pp. 323-330 ◽  
Author(s):  
Pierre-Alain Duc ◽  
Frédéric Bournaud ◽  
Médéric Boquien
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Numerical Simulations ◽  
Dwarf Galaxies ◽  
Star Clusters ◽  
Dense Core ◽  
Multi Wavelength ◽  
Interacting Systems ◽  
Super Star Clusters ◽  
Tidal Tails

AbstractStar formation may take place in a variety of locations in interacting systems: in the dense core of mergers, in the shock regions at the interface of the colliding galaxies and even within the tidal debris expelled into the intergalactic medium. Along tidal tails, objects may be formed with masses ranging from those of super-star clusters to dwarf galaxies: the so-called Tidal Dwarf Galaxies (TDGs). Based on a set of multi-wavelength observations and extensive numerical simulations, we show how TDGs may simultaneously be used as laboratories to study the process of star-formation (SFE, IMF) in a specific environment and as probes of various cosmological properties, such as the distribution of dark matter and satellites around galaxies.

scholarly journals Dark matter-deficient dwarf galaxies form via tidal stripping of dark matter in interactions with massive companions

2021 ◽  
Vol 502 (2) ◽  
pp. 1785-1796
Author(s):  
R A Jackson ◽  
S Kaviraj ◽  
G Martin ◽  
J E G Devriendt ◽  
A Slyz ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Evolution ◽  
Cold Dark Matter ◽  
Dwarf Galaxies ◽  
Stellar Mass ◽  
Matter Content ◽  
Mass Relation ◽  
Potential Wells ◽  
Tidal Interactions ◽  
New Interactions

ABSTRACT In the standard ΛCDM (Lambda cold dark matter) paradigm, dwarf galaxies are expected to be dark matter-rich, as baryonic feedback is thought to quickly drive gas out of their shallow potential wells and quench star formation at early epochs. Recent observations of local dwarfs with extremely low dark matter content appear to contradict this picture, potentially bringing the validity of the standard model into question. We use NewHorizon, a high-resolution cosmological simulation, to demonstrate that sustained stripping of dark matter, in tidal interactions between a massive galaxy and a dwarf satellite, naturally produces dwarfs that are dark matter-deficient, even though their initial dark matter fractions are normal. The process of dark matter stripping is responsible for the large scatter in the halo-to-stellar mass relation in the dwarf regime. The degree of stripping is driven by the closeness of the orbit of the dwarf around its massive companion and, in extreme cases, produces dwarfs with halo-to-stellar mass ratios as low as unity, consistent with the findings of recent observational studies. ∼30 per cent of dwarfs show some deviation from normal dark matter fractions due to dark matter stripping, with 10 per cent showing high levels of dark matter deficiency (Mhalo/M⋆ < 10). Given their close orbits, a significant fraction of dark matter-deficient dwarfs merge with their massive companions (e.g. ∼70 per cent merge over time-scales of ∼3.5 Gyr), with the dark matter-deficient population being constantly replenished by new interactions between dwarfs and massive companions. The creation of these galaxies is therefore a natural by-product of galaxy evolution and their existence is not in tension with the standard paradigm.

scholarly journals The Large-Scale Activity in NGC 1068

1989 ◽  
Vol 134 ◽  
pp. 343-344
Author(s):  
J. Bland ◽  
G. N. Cecil
Keyword(s):  
Large Scale ◽  
Physical State ◽  
Seyfert Galaxy ◽  
Optical Emission ◽  
Field Of View ◽  
Ionized Gas ◽  
Nuclear Activity ◽  
Fabry Perot ◽  
Ngc 1068 ◽  
Resolution Study

While NGC 1068 has received much attention in recent years, little is known of the large-scale dynamics and physical state of the ionized gas in this nearby Seyfert galaxy and, in particular, its connection with the nuclear activity. We have used the Hawaii Imaging Fabry-Perot Interferometer (HIFI) at the CFHT to obtain detailed spectrophotometry at 65 kms−1 resolution (FWHM) over the Hα and neighbouring [N II] lines. The final maps are derived from 100 000 fits to spectra taken at 0.4″ increments over a 200″ field-of-view. (A higher resolution study which concentrates on the circumnuclear, optical emission and its relation to the radio jet is presented at this conference by Cecil & Bland.)

Revealing the effects of galaxy interaction in the main galaxies of the southern group Arp 314

2020 ◽  
Vol 494 (2) ◽  
pp. 2785-2797
Author(s):  
S Torres-Flores ◽  
P Amram ◽  
D Olave-Rojas ◽  
N Muñoz-Elgueta ◽  
C Mendes de Oliveira ◽  
...  
Keyword(s):  
Gas Flows ◽  
Low Oxygen ◽  
Data Set ◽  
Oxygen Abundance ◽  
Star Forming ◽  
Star Forming Regions ◽  
Fabry Perot ◽  
Galaxy Interaction ◽  
Interacting Systems ◽  
Tidal Tails

ABSTRACT We present new Gemini imaging and spectroscopic data of the system Arp 314, which consists of a triplet of interacting galaxies. This new imagery exhibits tidal tails and stellar bridges between the galaxies' members and confirms the past interactions. Using this data set, we have analysed the physical properties of 22 star-forming regions located in the main disc of these galaxies, as well as in the intergalactic medium. All these regions have emission lines typical of young ages and a couple of them display very high Hα luminosities (LHα ∼ 1040 erg s−1). Using the star-forming regions located in Arp 314-1, we derive its gas-phase oxygen-abundance distribution, which suggests a flatter behaviour than the distribution shown by non-interacting systems. This is in agreement with results obtained for other interacting systems and simulations. The presence of gas flows, as indicated by its complex kinematics, could explain this finding. Most of the star formation in Arp 314-2 is located in a central starburst, where double Hα profiles can be identified, as shown by archival Fabry–Perot data. Additionally, we found that the irregular galaxy Arp 314-3 has a low oxygen abundance. Considering its luminosity, this object has a primordial origin, and it was not formed during the interaction event that this system has experienced.

scholarly journals Constraining the Distribution of Dark Matter Lumps Around the Milky Way Using Tidal Debris

2003 ◽  
Vol 208 ◽  
pp. 209-214
Author(s):  
Kathryn V. Johnston ◽  
David N. Spergel ◽  
Christian Haydn
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Tidal Tails

Dwarf galaxies that fall into the Milky Way's potential are tidally disrupted. Their tidal tails are one of the most powerful probes of the mass distribution in the Galaxy. If the distribution of dark matter in the Galaxy is lumpy, then these lumps will scatter stars in the stream and alter its shape. We describe our approach to using the tidal debris to constrain substructure in the Galaxy halo.

scholarly journals Dark matter density profiles in dwarf galaxies: linking Jeans modelling systematics and observation

2021 ◽  
Vol 507 (4) ◽  
pp. 4715-4733
Author(s):  
Laura J Chang ◽  
Lina Necib
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Particle Physics ◽  
Measurement Errors ◽  
Inner Core ◽  
Dwarf Galaxies ◽  
Complex Dynamics ◽  
Matter Content ◽  
Indirect Detection ◽  
Dark Matter Annihilation

ABSTRACT The distribution of dark matter in dwarf galaxies can have important implications on our understanding of galaxy formation as well as the particle physics properties of dark matter. However, accurately characterizing the dark matter content of dwarf galaxies is challenging due to limited data and complex dynamics that are difficult to accurately model. In this paper, we apply spherical Jeans modelling to simulated stellar kinematic data of spherical, isotropic dwarf galaxies with the goal of identifying the future observational directions that can improve the accuracy of the inferred dark matter distributions in the Milky Way dwarf galaxies. We explore how the dark matter inference is affected by the location and number of observed stars as well as the line-of-sight velocity measurement errors. We use mock observation to demonstrate the difficulty in constraining the inner core/cusp of the dark matter distribution with data sets of fewer than 10 000 stars. We also demonstrate the need for additional measurements to make robust estimates of the expected dark matter annihilation signal strength. For the purpose of deriving robust indirect detection constraints, we identify Ursa Major II, Ursa Minor, and Draco as the systems that would most benefit from additional stars being observed.

scholarly journals Identifying old Tidal Dwarf Galaxies in Simulations and in the Nearby Universe

2004 ◽  
Vol 217 ◽  
pp. 550-555 ◽  
Author(s):  
Pierre-Alain Duc ◽  
Frédéric Bournaud ◽  
Frédéric Masset
Keyword(s):  
Numerical Simulations ◽  
Umbilical Cord ◽  
Dwarf Galaxies ◽  
Heavy Elements ◽  
Con A ◽  
Local Universe ◽  
Tidal Tail ◽  
Identity Card ◽  
Interacting Systems ◽  
The Universe

Most Tidal Dwarf Galaxies (TDGs) so-far discussed in the literature may be considered as young ones or even newborns, as they are still physically linked to their parent galaxies by an umbilical cord: the tidal tail at the tip of which they are usually observed. Old Tidal Dwarf Galaxies, completely detached from their progenitors, are still to be found. Using N-body numerical simulations, we have shown that tidal objects as massive as 109 solar masses may be formed in interacting systems and survive for more than one Gyr. Old TDGs should hence exist in the Universe. They may be identified looking at a peculiarity of their “genetic identity card”: a relatively high abundance in heavy elements, inherited from their parent galaxies. Finally, using this technique, we revisit the dwarf galaxies in the local Universe trying to find arguments pro and con a tidal origin.

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