scholarly journals Stellar Orbits in Doubly-Barred Galaxies

1996 ◽  
Vol 157 ◽  
pp. 464-466
Author(s):  
H. Hasan
Keyword(s):  
Galactic Center ◽  
Observational Evidence ◽  
Stellar Kinematics ◽  
Stellar Orbits ◽  
Barred Galaxies ◽  
Secular Evolution

The question of bars within bars has been reviewed by Friedli and Martinet (1993), who have also performed N-body simulations to produce nested bars. They propose that if a system of embedded bars is effective in transporting gas to the galactic center (Shlosman et al. 1989), then it is perhaps a step in the secular evolution of barred galaxies. In order to pursue this interesting proposition, and also because observational evidence for the existence of secondary bars is mounting (e.g. Buta & Crocker 1993; Shaw et al. 1993, Wozniak et al. 1995), it is important to understand the stellar kinematics in such systems.

scholarly journals Kinematic signatures of nuclear discs and bar-driven secular evolution in nearby galaxies of the MUSE TIMER project

2020 ◽  
Vol 643 ◽  
pp. A14 ◽  
Author(s):  
Dimitri A. Gadotti ◽  
Adrian Bittner ◽  
Jesús Falcón-Barroso ◽  
Jairo Méndez-Abreu ◽  
Taehyun Kim ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Signal ◽  
Stellar Kinematics ◽  
Barred Galaxies ◽  
Secular Evolution ◽  
Integral Field Spectroscopy ◽  
Theoretical Predictions ◽  
Central Regions ◽  
Nearby Galaxies ◽  
Formation And Evolution

The central regions of disc galaxies hold clues to the processes that dominate their formation and evolution. To exploit this, the TIMER project has obtained high signal-to-noise and spatial resolution integral-field spectroscopy data of the inner few kpc of 21 nearby massive barred galaxies, which allows studies of the stellar kinematics in their central regions with unprecedented spatial resolution. We confirm theoretical predictions of the effects of bars on stellar kinematics and identify box/peanuts through kinematic signatures in mildly and moderately inclined galaxies, finding a lower limit to the fraction of massive barred galaxies with box/peanuts at ∼62%. Further, we provide kinematic evidence of the connection between barlenses, box/peanuts, and bars. We establish the presence of nuclear discs in 19 galaxies and show that their kinematics are characterised by near-circular orbits with low pressure support and that they are fully consistent with the bar-driven secular evolution picture for their formation. In fact, we show that these nuclear discs have, in the region where they dominate, larger rotational support than the underlying main galaxy disc. In addition, we define a kinematic radius for the nuclear discs and show that it relates to bar radius, ellipticity and strength, and bar-to-total ratio. Comparing our results with photometric studies of galaxy bulges, we find that careful, state-of-the-art galaxy image decompositions are generally able to discern nuclear discs from classical bulges if the images employed have high enough physical spatial resolution. In fact, we show that nuclear discs are typically identified in such image decompositions as photometric bulges with (near-)exponential profiles. However, we find that the presence of composite bulges (galaxies hosting both a classical bulge and a nuclear disc) can often be unnoticed in studies based on photometry alone and suggest a more stringent threshold to the Sérsic index to identify galaxies with pure classical bulges.

scholarly journals MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER

2009 ◽  
Vol 692 (2) ◽  
pp. 1075-1109 ◽  
Author(s):  
S. Gillessen ◽  
F. Eisenhauer ◽  
S. Trippe ◽  
T. Alexander ◽  
R. Genzel ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Stellar Orbits

scholarly journals Composite bulges – II. Classical bulges and nuclear discs in barred galaxies: the contrasting cases of NGC 4608 and NGC 4643

2021 ◽  
Vol 502 (2) ◽  
pp. 2446-2473
Author(s):  
Peter Erwin ◽  
Anil Seth ◽  
Victor P Debattista ◽  
Marja Seidel ◽  
Kianusch Mehrgan ◽  
...  
Keyword(s):  
Large Scale ◽  
Stellar Kinematics ◽  
Barred Galaxies ◽  
Circular Structure ◽  
Model Predictions ◽  
The Galaxy ◽  
Central Regions ◽  
Total Light ◽  
Kinematic Analyses ◽  
Stellar Kinematic

ABSTRACT We present detailed morphological, photometric, and stellar-kinematic analyses of the central regions of two massive, early-type barred galaxies with nearly identical large-scale morphologies. Both have large, strong bars with prominent inner photometric excesses that we associate with boxy/peanut-shaped (B/P) bulges; the latter constitute ∼30 per cent of the galaxy light. Inside its B/P bulge, NGC 4608 has a compact, almost circular structure (half-light radius Re ≈ 310 pc, Sérsic n = 2.2) we identify as a classical bulge, amounting to 12.1 per cent of the total light, along with a nuclear star cluster (Re ∼ 4 pc). NGC 4643, in contrast, has a nuclear disc with an unusual broken-exponential surface-brightness profile (13.2 per cent of the light), and a very small spheroidal component (Re ≈ 35 pc, n = 1.6; 0.5 per cent of the light). IFU stellar kinematics support this picture, with NGC 4608’s classical bulge slowly rotating and dominated by high velocity dispersion, while NGC 4643’s nuclear disc shows a drop to lower dispersion, rapid rotation, V–h3 anticorrelation, and elevated h4. Both galaxies show at least some evidence for V–h3correlation in the bar (outside the respective classical bulge and nuclear disc), in agreement with model predictions. Standard two-component (bulge/disc) decompositions yield B/T ∼ 0.5–0.7 (and bulge n > 2) for both galaxies. This overestimates the true ‘spheroid’ components by factors of 4 (NGC 4608) and over 100 (NGC 4643), illustrating the perils of naive bulge-disc decompositions applied to massive barred galaxies.

The Smaller Alignment Index (SALI) applied in a study of stellar orbits in barred galaxies potential models using the LP-VIcode

New Astronomy ◽  
2018 ◽  
Vol 60 ◽  
pp. 48-60 ◽  
Author(s):  
Lucas Antonio Caritá ◽  
Irapuan Rodrigues ◽  
Ivânio Puerari ◽  
Luiz Eduardo Camargo Aranha Schiavo
Keyword(s):  
Potential Models ◽  
Stellar Orbits ◽  
Barred Galaxies

scholarly journals Testing the black hole no-hair theorem with Galactic Center stellar orbits

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
Hong Qi ◽  
Richard O’Shaughnessy ◽  
Patrick Brady
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Stellar Orbits

scholarly journals Kinematical signatures of disc instabilities and secular evolution in the MUSE TIMER Survey

2019 ◽  
Vol 14 (S353) ◽  
pp. 135-139
Author(s):  
Dimitri A. Gadotti ◽  
Adrian Bittner ◽  
Jesus Falcón-Barroso ◽  
Jairo Méndez-Abreu ◽  
Keyword(s):  
Spatial Resolution ◽  
High Signal ◽  
Stellar Kinematics ◽  
Secular Evolution ◽  
Integral Field Spectroscopy ◽  
Central Regions ◽  
Hydrodynamical Simulations ◽  
Cosmic History ◽  
Disc Galaxies ◽  
Integral Field

AbstractThe MUSE TIMER Survey has obtained high signal and high spatial resolution integral-field spectroscopy data of the inner ~ 6×6 kpc of 21 nearby massive disc galaxies. This allows studies of the stellar kinematics of the central regions of massive disc galaxies that are unprecedented in spatial resolution. We confirm previous predictions from numerical and hydrodynamical simulations of the effects of bars and inner bars on stellar and gaseous kinematics, and also identify box/peanuts via kinematical signatures in mildly and moderately inclined galaxies, including a box/peanut in a face-on inner bar. In 20/21 galaxies we find inner discs and show that their properties are fully consistent with the bar-driven secular evolution picture for their formation. In addition, we show that these inner discs have, in the region where they dominate, larger rotational support than the main galaxy disc, and discuss how their stellar population properties can be used to estimate when in cosmic history the main bar formed. Our results are compared with photometric studies in the context of the nature of galaxy bulges and we show that inner discs are identified in image decompositions as photometric bulges with exponential profiles (i.e., Sérsic indices near unity).

scholarly journals Periastron shifts of stellar orbits near the Galactic Center

2001 ◽  
Vol 374 (1) ◽  
pp. 95-104 ◽  
Author(s):  
G. F. Rubilar ◽  
A. Eckart
Keyword(s):  
Galactic Center ◽  
Stellar Orbits

scholarly journals Testing properties of the Galactic center black hole using stellar orbits

2010 ◽  
Vol 81 (6) ◽  
Author(s):  
David Merritt ◽  
Tal Alexander ◽  
Seppo Mikkola ◽  
Clifford M. Will
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Stellar Orbits
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