Circumnuclear Structures in the Interacting Seyfert Galaxy NGC 1241: Kinematics and Optical/Infrared Morphology

Díaz, Rubén; Dottori, H.; Vera-Villamizar, N.; Carranza, G.

doi:10.1086/381215

Cited by 10 publications

(15 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As predicted by simulations, there is plenty of fuel -the central concentration of molecular gas is higher in barred than in unbarred galaxies (Sakamoto et al 1999). Additional examples of nuclear star formation rings -and multiple discussions of the best cases -can be found in van der Kruit (1974Kruit ( , 1976; Rubin, Ford, & Peterson (1975); Sandage & Brucato (1979); ;Gerin, Nakai, & Combes (1988); Benedict et al (1992Benedict et al ( , 1993Benedict et al ( , 1996Benedict et al ( , 2002; Buta (1986aButa ( , b, 1988Buta ( , 1995; Pogge (1989); García-Barreto et al (1991); ; ; Pogge & Eskridge (1993: NGC 1819; Forbes et al (1994a, b); Quillen et al (1995); Phillips et al (1996); Buta & Combes (1996); Maoz et al (1996); Regan et al (1996); Elmegreen et al (1997); Colina et al (1997); Contini et al (1997);Vega Beltrán et al (1998); Buta & Purcell (1998) ;Buta, Crocker, & Byrd (1999); Martini & Pogge (1999); ; Pérez-Ramírez et al (2000, 2001; Wong & Blitz (2000, 2001; Waller et al (2001); Lourenso et al (2001); Alonso-Herrero, ; Díaz et al (2002); …”

Section: Figurementioning

confidence: 99%

See 1 more Smart Citation

Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

Kormendy¹,

Kennicutt

2004

Annu. Rev. Astron. Astrophys.

1,764

107

2,359

View full text Add to dashboard Cite

The Universe is in transition. At early times, galactic evolution was dominated by hierarchical clustering and merging, processes that are violent and rapid. In the far future, evolution will mostly be secular: the slow rearrangement of energy and mass that results from interactions involving collective phenomena such as bars, oval disks, spiral structure, and triaxial dark halos. Both processes are important now. This paper reviews internal secular evolution, concentrating on one important consequence, the buildup of dense central components in disk galaxies that look like classical, merger-built bulges but that were made slowly out of disk gas. We call these pseudobulges.We begin with an "existence proof" -a review of how bars rearrange disk gas into outer rings, inner rings, and stuff dumped onto the center. Simulation results correspond closely to the morphology of barred galaxies. In the simulations, gas transported to small radii reaches high densities that plausibly feed star formation. In the observations, many SB and oval galaxies have dense central concentrations of gas and star formation. Optical colors and spectra often imply young stellar populations. So the formation of pseudobulges is well supported by theory and observations. It is embedded in a broader evolution picture that accounts for much of the richness observed in galaxy structure.If secular processes built dense central components that masquerade as bulges, how can we distinguish them from merger-built bulges? Observations show that pseudobulges retain a memory of their disky origin. 2That is, they have one or more characteristics of disks: (1) flatter shapes than those of classical bulges, (2) correspondingly large ratios of ordered to random velocities indicative of disk dynamics, (3) small velocity dispersions σ with respect to the Faber-Jackson correlation between σ and bulge luminosity, (4) spiral structure or nuclear bars in the "bulge" part of the light profile, (5) nearly exponential brightness profiles, and (6) starbursts. These structures occur preferentially in barred and oval galaxies in which secular evolution should be most rapid. So the cleanest examples of pseudobulges are recognizable.Are their formation timescales plausible? We use measurements of central gas densities and star formation rates to show that pseudobulges of the observed densities form on reasonable timescales of a few billion years.Thus a large variety of observational and theoretical results contribute to a new picture of galaxy evolution that complements hierarchical clustering and merging. Secular evolution consists of more than the aging of stellar populations. Every galaxy is dynamically evolving.

show abstract

Section: Figurementioning

confidence: 99%

“…Local Group examples occur in M 31 (e. g., Lauer et al 1993), M 33, and NGC 205 (Jones et al 1996. Not much farther away are nuclei in IC 342 (Böker et al 1997(Böker et al , 1999 and in NGC 7793 (Díaz et al 2002). The literature on nuclei is extensive; we review only the part of it that is relevant to this paper.…”

Section: Nucleimentioning

confidence: 99%

Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

Kormendy¹,

Kennicutt

2004

Annu. Rev. Astron. Astrophys.

1,764

107

2,359

View full text Add to dashboard Cite

show abstract

“…Such a torque leads to the formation of interesting morphological substructures in the gaseous medium. Typical features include a pair of dust lanes related to shocks at the leading side of the bar (e.g., Athanassoula 1992b), a circum-nuclear star-forming ring (or nuclear ring for brevity) near the galactic center (e.g., Buta 1986;Garcia-Barreto et al 1991;Barth et al 1995;Maoz et al 2001;Mazzuca et al 2008), and nuclear spirals inside the ring that may be a channel for gas infall to fuel the central black hole (BH) (e.g., Shlosman et al 1990;Regan & Mulchaey 1999;Knapen et al 2000;Díaz et al 2003;Laurikainen et al 2004;van de Ven & Fathi 2010;Kim et al 2012a). These substructures are commonly observed in nearby barred galaxies and are studied in previous simulations (e.g., Sanders & Huntley 1976;Roberts et al 1979;Schwarz 1981;van Albada & Roberts 1981;Buta & Combes 1996;Martini et al 2003aMartini et al , 2003b.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamical Simulations of Nuclear Rings in Barred Galaxies

Shen

Kim

2015

ApJ

View full text Add to dashboard Cite

Dust lanes, nuclear rings, and nuclear spirals are typical gas structures in the inner region of barred galaxies. Their shapes and properties are linked to the physical parameters of the host galaxy. We use high-resolution hydrodynamical simulations to study 2D gas flows in simple barred galaxy models. The nuclear rings formed in our simulations can be divided into two groups: one group is nearly round and the other is highly elongated. We find that roundish rings may not form when the bar pattern speed is too high or the bulge central density is too low. We also study the periodic orbits in our galaxy models, and find that the concept of inner Lindblad resonance (ILR) may be generalized by the extent of x 2 orbits. All roundish nuclear rings in our simulations settle in the range of x 2 orbits (or ILRs). However, knowing the resonances is insufficient to pin down the exact location of these nuclear rings. We suggest that the backbone of round nuclear rings is the x 2 orbital family, i.e., round nuclear rings are allowed only in the radial range of x 2 orbits. A round nuclear ring forms exactly at the radius where the residual angular momentum of infalling gas balances the centrifugal force, which can be described by a parameter f ring measured from the rotation curve. The gravitational torque on gas in high pattern speed models is larger, leading to a smaller ring size than in the low pattern speed models. Our result may have important implications for using nuclear rings to measure the parameters of real barred galaxies with 2D gas kinematics.

show abstract

“…The Paα image shows intense star formation at the nucleus and CNR (Díaz et al 2003). Nevertheless their star formation does not show dust in the form of lanes and patches (Regan & Mulchaey 1999).…”

Section: Preliminary Results and Discussionmentioning

confidence: 97%

“…Circumnuclear structures as well as the kinematics and perturbing patterns at hundred parsecs scale, were studied in the interacting Sy galaxy NGC 1241 by Díaz et al (2003).…”

Section: Introductionmentioning

confidence: 99%

Is the (J-Ks) excess in the nuclear region of NGC 1241 due to dust or to C-stars?

et al. 2004

Self Cite

View full text Add to dashboard Cite

Abstract. NGC 1241 is a Sy 2 galaxy with a 1.4 kpc circumnuclear ring (CNR) of star formation revealed in Paα. A 0.3 kpc long Paα emitting bar centered on the nucleus is present, apparently without associated absorption features. GEMINI (+QUIRC+Hokupa) IR pixel-photometry reveals instead an azimuthally symmetric (J − Ks) color which is redder at the nucleus than at the CNR. This property may well be due to the increasing importance of dust when going from the ring inward into the nucleus. Nevertheless the (V − H) color does not indicate special absorption conditions in the nucleus with respect to the CNR, and no absorption features are evident, as normally expected near emitting bars. Then, we propose as an alternative explanation an excess of C-stars in the nuclear region which decreases outwards until reaching the CNR and its colors. We have compared the pixel color-magnitude diagram with the 2-MASS (J − K s ) vs. Ks diagram for the Large Magellanic Cloud: about 5 × 10 2 C-stars and 2.5 × 10 4 AGB Oxygen-rich stars inside r ∼ 50 pc, are enough to reproduce the observed nuclear tip in the diagram. This stars would release gas that, gravitationally bounded, pollutes the nuclear environment and could amount 10 −2 to 10 −1 M yr −1 of fuel for the central engine during the lifetime of stars with masses 2 M < MCStars < 6 M . This scenario may also explain the observed increased strength of the CN-bands in the stellar populations of Sy 2 nuclei, and the recent claim of a significant contribution of intermediate age stars to the optical continuum of low luminosity AGNs.

show abstract

Circumnuclear Structures in the Interacting Seyfert Galaxy NGC 1241: Kinematics and Optical/Infrared Morphology

Cited by 10 publications

References 43 publications

Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

Hydrodynamical Simulations of Nuclear Rings in Barred Galaxies

Is the (J-Ks) excess in the nuclear region of NGC 1241 due to dust or to C-stars?

Contact Info

Product

Resources

About