| 1. |
- Falcón-Barroso, Jesús, et al.
(författare)
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A Sauron Study of Stars and Gas in SA Bulges
- 2007
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Ingår i: Island Universes.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present results from our ongoing effort to understand the morphological and kinematical properties of early-type galaxies using the integral-field spectrograph SAURON. We discuss the relation between the stellar and gas morphology and kinematics in our sub-sample of 24 representative Sa spiral bulges. We focus on the frequency of kinematically decoupled components and on the presence of star formation in circumnuclear rings.
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| 2. |
- Fathi, Kambiz, et al.
(författare)
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Quantifying Resonant Structure in NGC 6946 from Two-dimensional Kinematics
- 2007
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Ingår i: Astrophysical Journal Letters. ; 667:137
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Tidskriftsartikel (refereegranskat)abstract
- We study the two-dimensional kinematics of the Hα-emitting gas in the nearby barred Scd galaxy NGC 6946, in order to determine the pattern speed of the primary m=2 perturbation mode. The pattern speed is a crucial parameter for constraining the internal dynamics, estimating the impact velocities of the gravitational perturbation at the resonance radii, and setting up an evolutionary scenario for NGC 6946. Our data allow us to derive the best-fitting kinematic position angle and the geometry of the underlying gaseous disk, which we use to derive the pattern speed using the Tremaine-Weinberg method. We find a main pattern speed ΩPp=22+4-1 km s-1 kpc-1, but our data clearly reveal the presence of an additional pattern speed ΩSp=47+3-2 km s-1 kpc-1 in a zone within 1.25 kpc of the nucleus. Using the epicyclic approximation, we deduce the location of the resonance radii and confirm that inside the outer inner Lindblad resonance radius of the main oval, a primary bar has formed rotating at more than twice the outer pattern speed. We further confirm that a nuclear bar has formed inside the inner Lindblad resonance radius of the primary bar, coinciding with the inner inner Lindblad resonance radius of the large-scale m=2 mode oval.
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| 3. |
- Peletier, R. F., et al.
(författare)
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Stars and gas in the inner parts of galaxies seen in SAURON integral field observations
- 2007
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Ingår i: New Astronomy Reviews. - : Elsevier BV. - 1387-6473. ; 51:1-2, s. 29-33
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Tidskriftsartikel (refereegranskat)abstract
- We give two examples of spiral galaxies that show non-circular gas motions in the inner kiloparsecs, from SAURON integral field spectroscopy. We use harmonic decomposition of the velocity field of the ionized gas to study the underlying mass distribution, employing linear theory. The higher order harmonic terms and the main kinematic features of the observed data are consistent with an analytically constructed simple bar model. We also present maps of a number of strong absorption lines in M 100, derive simple stellar populations and correlate them with features in the gas kinematics.
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| 4. |
- Toonen, Silvia, et al.
(författare)
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The Pattern Speeds of NGC 6946
- 2008
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Ingår i: Astronomical Society of the Pacific conference series. ; , s. 2-, s. 322-
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Konferensbidrag (populärvet., debatt m.m.)abstract
- We study the kinematics of the barred spiral galaxy NGC 6946 by investigating the velocity field from Hα Fabry-Perot observations, determine the pattern speed of the bar by using the Tremaine-Weinberg method, and find a main pattern speed of 21.7+4.0-0.8 km-1 s-1 kpc-1. Our data clearly suggest the presence of an additional pattern with a pattern speed more than twice that of the large pattern in this galaxy. We use the epicycle approximation to deduce the location of the resonance radii and subsequently determine the pattern speed between the radii, and find that inside the inner inner Lindblad resonance radius a bar-like system has evolved.
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