scholarly journals Evolution of Galaxies in Triaxial Halos with Figure Rotation

2004 ◽  
Vol 220 ◽  
pp. 299-304
Author(s):  
Kenji Bekki ◽  
K. C. Freeman
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Dynamical Evolution ◽  
Dark Matter Halo ◽  
Disk Galaxies ◽  
Formation Processes ◽  
Dark Matter Halos ◽  
Low Surface Brightness ◽  
Figure Rotation ◽  
Bar Formation

Firstly, we demonstrate that unusually large outer HI spiral arms observed in NGC 2915 can form in an extended gas disk embedded in a massive triaxial dark matter halo with slow figure rotation, through the strong gravitational torque of the rotating halo. Secondly, we show that the figure rotation of a triaxial dark matter halo can influence dynamical evolution of disk galaxies by using fully self-consistent numerical simulations. We particularly describe the formation processes of “halo-triggered” bars in thin galactic disks dominated by dark matter halos with figure rotation and discuss the origin of stellar bars in low luminosity, low surface brightness (LSB) disk galaxies. Thirdly, we provide several implications of the present numerical results in terms of triggering mechanism of starbursts in galaxies and stellar bar formation in high redshifts.

scholarly journals Massive low-surface-brightness galaxies in the eagle simulation

2020 ◽  
Vol 496 (3) ◽  
pp. 3996-4016
Author(s):  
Andrea Kulier ◽  
Gaspar Galaz ◽  
Nelson D Padilla ◽  
James W Trayford
Keyword(s):  
Dark Matter ◽  
Angular Momentum ◽  
Surface Density ◽  
Surface Brightness ◽  
Initial Conditions ◽  
High Surface ◽  
Formation Rate ◽  
Dark Matter Halo ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

ABSTRACT We investigate the formation and properties of low surface brightness galaxies (LSBGs) with M* > 109.5 M⊙ in the eagle hydrodynamical cosmological simulation. Galaxy surface brightness depends on a combination of stellar mass surface density and mass-to-light ratio (M/L), such that low surface brightness is strongly correlated with both galaxy angular momentum (low surface density) and low specific star formation rate (high M/L). This drives most of the other observed correlations between surface brightness and galaxy properties, such as the fact that most LSBGs have low metallicity. We find that LSBGs are more isolated than high-surface-brightness galaxies (HSBGs), in agreement with observations, but that this trend is driven entirely by the fact that LSBGs are unlikely to be close-in satellites. The majority of LSBGs are consistent with a formation scenario in which the galaxies with the highest angular momentum are those that formed most of their stars recently from a gas reservoir co-rotating with a high-spin dark matter halo. However, the most extended LSBG discs in EAGLE, which are comparable in size to observed giant LSBGs, are built up via mergers. These galaxies are found to inhabit dark matter haloes with a higher spin in their inner regions (<0.1r200c), even when excluding the effects of baryonic physics by considering matching haloes from a dark-matter-only simulation with identical initial conditions.

scholarly journals Constraints on the Structure of Dark Matter Halos from the Rotation Curves of Low Surface Brightness Galaxies

2000 ◽  
Vol 119 (4) ◽  
pp. 1579-1591 ◽  
Author(s):  
Frank C. van den Bosch ◽  
Brant E. Robertson ◽  
Julianne J. Dalcanton ◽  
W. J. G. de Blok
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Dark Matter Halos ◽  
Rotation Curves ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

scholarly journals Observational insights on the origin of giant low surface brightness galaxies

2021 ◽  
Vol 503 (1) ◽  
pp. 830-849
Author(s):  
Anna S Saburova ◽  
Igor V Chilingarian ◽  
Anastasia V Kasparova ◽  
Olga K Sil’chenko ◽  
Kirill A Grishin ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
High Surface ◽  
Dark Matter Halo ◽  
High Mass ◽  
Formation Mechanisms ◽  
Orbital Parameters ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

ABSTRACT Giant low surface brightness galaxies (gLSBGs) with dynamically cold stellar discs reaching the radius of 130 kpc challenge currently considered galaxy formation mechanisms. We analyse new deep long-slit optical spectroscopic observations, archival optical images, and published Hi and optical spectroscopic data for a sample of seven gLSBGs, for which we performed mass modelling and estimated the parameters of dark matter haloes assuming the Burkert dark matter density profile. Our sample is not homogeneous by morphology, parameters of stellar populations, and total mass, however, six of seven galaxies sit on the high-mass extension of the baryonic Tully–Fisher relation. In UGC 1382, we detected a global counterrotation of the stellar high surface brightness (HSB) disc with respect to the extended LSB disc. In UGC 1922 with signatures of a possible merger, the gas counterrotation is seen in the inner disc. Six galaxies host active galactic nuclei, three of which have the estimated black hole masses substantially below those expected for their (pseudo-)bulge properties suggesting poor merger histories. Overall, the morphology, internal dynamics, and low star formation efficiency in the outer discs indicate that the three formation scenarios shape gLSBGs: (i) a two-stage formation when an HSB galaxy is formed first and then grows an LSB disc by accreting gas from an external supply; (ii) an unusual shallow and extended dark matter halo; (iii) a major merger with fine-tuned orbital parameters and morphologies of the merging galaxies.

A full pipeline for modelling low surface brightness galaxies

2019 ◽  
Vol 14 (S353) ◽  
pp. 279-280
Author(s):  
Marius Peper ◽  
Boudewijn F. Roukema ◽  
Krzysztof Bolejko
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
Dark Matter Halo ◽  
Cosmological Simulations ◽  
Galaxy Formation And Evolution ◽  
Low Surface Brightness ◽  
Formation And Evolution ◽  
Low Surface Brightness Galaxies

AbstractCosmological simulations are a powerful tool to test various cosmological and galaxy formation scenarios. The discovery of low surface brightness objects has been a challenge for both of these fields. Our work aims to create a fully reproducible pipeline to generate a realistic dark matter halo catalog with corresponding information on galaxy formation and evolution.

scholarly journals Flaring stellar disk in the low surface brightness galaxy UGC 7321

2019 ◽  
Vol 628 ◽  
pp. A58 ◽  
Author(s):  
S. Sarkar ◽  
C. J. Jog
Keyword(s):  
Dark Matter ◽  
Density Distribution ◽  
Surface Brightness ◽  
Vertical Structure ◽  
Hydrogen Gas ◽  
Dark Matter Halo ◽  
Stellar Disk ◽  
Disk System ◽  
Disk Model ◽  
Low Surface Brightness

We theoretically study the vertical structure of the edge-on low surface brightness (LSB) galaxy UGC 7321. This is one of the few well-observed LSBs. We modeled it as a gravitationally coupled disk system of stars and atomic hydrogen gas in the potential of the dark matter halo and treated the realistic case where the rotation velocity varies with radius. We used a dense and compact halo as implied by the observed rotation curve in this model. We calculated the thickness of stellar and HI disks in terms of the half-width at half-maximum of the vertical density distribution in a region of R = 0–12 kpc using input parameters constrained by observations. We obtain a mildly increasing disk thickness up to R = 6 kpc, in a good agreement with the observed trend, and predict a strong flaring beyond this. To obtain this trend, the stellar velocity dispersion has to fall exponentially at a rate of 3.2RD, while the standard value of 2RD gives a decreasing thickness with radius. Interestingly, both stellar and HI disks show flaring in the outer disk region although they are dynamically dominated by the dark matter halo from the very inner radii. The resulting vertical stellar density distribution cannot be fit by a single sech2/n function, in agreement with observations, which show wings at larger distances above the mid-plane. Invoking a double-disk model to explain the vertical structure of LSBs as done in the literature may therefore not be necessary.

scholarly journals The universal rotation curve of low surface brightness galaxies – IV. The interrelation between dark and luminous matter

2019 ◽  
Vol 490 (4) ◽  
pp. 5451-5477 ◽  
Author(s):  
Chiara Di Paolo ◽  
Paolo Salucci ◽  
Adnan Erkurt
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Rotation Curve ◽  
High Surface ◽  
Dark Matter Halo ◽  
Rotation Curves ◽  
Central Surface ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Lsb Galaxies

ABSTRACT We investigate the properties of the baryonic and the dark matter components in low surface brightness (LSB) disc galaxies, with central surface brightness in the B band $\mu _0 \ge 23 \, \mathrm{mag \, arcsec}^{-2}$. The sample is composed of 72 objects, whose rotation curves show an orderly trend reflecting the idea of a universal rotation curve (URC) similar to that found in the local high surface brightness (HSB) spirals in previous works. This curve relies on the mass modelling of the co-added rotation curves, involving the contribution from an exponential stellar disc and a Burkert cored dark matter halo. We find that the dark matter is dominant especially within the smallest and less luminous LSB galaxies. Dark matter haloes have a central surface density $\Sigma _0 \sim 100 \, \mathrm{M}_{\odot } \, \mathrm{pc}^{-2}$, similar to galaxies of different Hubble types and luminosities. We find various scaling relations among the LSBs structural properties which turn out to be similar but not identical to what has been found in HSB spirals. In addition, the investigation of these objects calls for the introduction of a new luminous parameter, the stellar compactness C* (analogously to a recent work by Karukes & Salucci), alongside the optical radius and the optical velocity in order to reproduce the URC. Furthermore, a mysterious entanglement between the properties of the luminous and the dark matter emerges.

scholarly journals The dark matter halos of the bluest low surface brightness galaxies

2006 ◽  
Vol 452 (3) ◽  
pp. 857-868 ◽  
Author(s):  
E. Zackrisson ◽  
N. Bergvall ◽  
T. Marquart ◽  
G. Östlin
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Dark Matter Halos ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

scholarly journals The Central Dynamics of Blue Low Surface Brightness Galaxies

2004 ◽  
Vol 220 ◽  
pp. 335-336
Author(s):  
Erik Zackrisson ◽  
Nils Bergvall
Keyword(s):  
Dark Matter ◽  
Density Profile ◽  
Surface Brightness ◽  
Cold Dark Matter ◽  
Central Density ◽  
Disk Galaxies ◽  
Rotation Curves ◽  
Central Surface ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We use optical, long-slit rotation curves to derive the slope of the central density profile in three blue disk galaxies with very faint central surface brightness values. We find the result to be in conflict with current cold dark matter predictions and to lend further support for pseudo-isothermal spheres as superior models for the dark halos of galaxies.

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