Gravitational Bar and Spiral Arm Torques fromKs-band Observations and Implications for the Pattern Speeds

Block, David L.; Buta, Ronald J.; Knapen, Johan H.; Elmegreen, D. M.; Elmegreen, Bruce G.; Puerari, I.

doi:10.1086/421362

Cited by 81 publications

(114 citation statements)

References 68 publications

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“…First, it is singular at corotation. Buta et al (2003) and Block et al (2004) place NGC 6951's bar radius at 3.0 kpc and indeed, as can be seen from Fig. 9 (top, right), our model does not extend to corotation.…”

Section: Description Of the Modelsupporting

confidence: 57%

“…There are several arguments that gas inflow is currently occurring in this galaxy. A large-scale stellar bar has been detected in the near-infrared (Buta et al 2003;Block et al 2004) with a bar radius of 26 (≈3.0 kpc) and a position angle of 84 • (Mulchaey et al 1997). This galaxy also shows a pronounced starburst (SB) ring at 5 (=580 pc) radius in Hα (Pérez et al 2000;Rozas et al 2002) and radio (Saikia et al 2002) emission.…”

Section: Introductionmentioning

confidence: 99%

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Molecular gas in NUclei of GAlaxies (NUGA)

Laan

Schinnerer

Boone

et al. 2011

A&A

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Within the NUclei of GAlaxies (NUGA) project we have obtained IRAM PdBI and 30 m 12 CO(1−0) and 12 CO(2−1) observations of the spiral galaxy NGC 6951. Previous work shows that there is indirect evidence of gas inflow from 3 kpc down to small radii: a largescale stellar bar, a prominent starburst ring (r ≈ 580 pc) and a LINER/Seyfert 2 nucleus. In this paper we study the gas kinematics as traced by the CO line emission in detail. We quantify the influence of the large-scale stellar bar by constructing an analytical model of the evolution of gas particles in a barred potential. From this model gravitational torques and mass accumulation rates are computed. We compare our model-based gravitational torque results with previous observationally-based ones. The model also shows that the large-scale stellar bar is indeed the dominant force for driving the gas inward, to the starburst ring. Inside the ring itself a nuclear stellar oval might play an important role. Detailed analysis of the CO gas kinematics there shows that emission arises from two co-spatial, but kinematically distinct components at several locations. The main emission component can always be related to the overall bar-driven gas kinematics. The second component exhibits velocities that are larger than expected for gas on stable orbits, has a molecular gas mass of 1.8 × 10 6 M , is very likely connected to the nuclear stellar oval, and is consistent with inflowing motion towards the very center. This may form the last link in the chain of gas inflow towards the active galactic nucleus in NGC 6951.

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Section: Description Of the Modelsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Molecular gas in NUclei of GAlaxies (NUGA)

Laan

Schinnerer

Boone

et al. 2011

A&A

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“…For NGC 1530 and NGC 6951 (a nuclear ring galaxy from Knapen et al 2002 included in Fig. 6) new values for Q b were derived by Buta et al (2003) and Block et al (2004) using a refinement of the original Q b technique, which allows the separate contributions from spiral arms and bar to the overall gravitational torque to (NGC 4736) no Q b has been published. With a relative nuclear ring size of 0.152 and a weak bar, the nuclear ring in this galaxy would, however, be in the upper left corner.…”

Section: Large Nuclear Rings Occur In Weak Barsmentioning

confidence: 99%

Structure and star formation in disk galaxies

Knapen¹

2004

A&A

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Abstract. From Hα images of a carefully selected sample of 57 relatively large, Northern spiral galaxies with low inclination, we study the distribution of the Hα emission in the circumnuclear and nuclear regions. At a resolution of around 100 parsec, we find that the nuclear Hα emission in the sample galaxies is often peaked, and significantly more often so among AGN host galaxies. The circumnuclear Hα emission, within a radius of two kpc, is often patchy in late-type, and absent or in the form of a nuclear ring in early-type galaxies. There is no clear correlation of nuclear or circumnuclear Hα morphology with the presence or absence of a bar in the host galaxy, except for the nuclear rings which occur in barred hosts. The presence or absence of close bright companion galaxies does not affect the circumnuclear Hα morphology, but their presence does correlate with a higher fraction of nuclear Hα peaks. Nuclear rings occur in at least 21% (±5%) of spiral galaxies, and occur predominantly in galaxies also hosting an AGN. Only two of our 12 nuclear rings occur in a galaxy which is neither an AGN nor a starburst host. We confirm that weaker bars host larger nuclear rings. The implications of these results on our understanding of the occurrence and morphology of massive star formation, as well as non-stellar activity, in the central regions of galaxies are discussed.

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“…(a) (b) (1-0) is plotted with steps of 0.6, 0.9, 1.5, 1.9, 3, 4, 6, 8, 13, 20, 30, 40, 60, 80, existence of correlation between the bar strength and bar ellipticity (Athanassoula 1992;Martinet & Friedli 1997;Abraham & Merrifield 2000;Block et al 2001;Block et al 2004;Comerón et al 2010;Kim et al 2012). The Spitzer project of S 4 G (Sheth et al 2010) has decomposed the galactic structure of NGC 5430 by using the GALFIT package and the Spitzer IRAC 3.6 µm image, by assuming a three-component bulge-disk-bar model (Salo et al 2015).…”

Section: Central Concentration Of Molecular Gas and Bar Strengthmentioning

confidence: 99%

Constraints on the minor merging and star formation history of the Wolf–Rayet galaxy NGC 5430 through observations

Pan

Kuno

Saito

et al. 2015

Publications of the Astronomical Society of Japan

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We used multi-wavelength analysis of the newly observed molecular gas ( 12 CO and 13 CO (1-0)) with interferometer CARMA and archival star formation tracers to constrain the interaction, merging, and star formation history of an off-center minor merger, a three-spiral barred galaxy NGC 5430 and its satellite embedded in the bar. Morphology of the molecular gas in the bar of NGC 5430 shows minimal signs of recent interactions in our resolution. The apparent morphological remnant of the past galaxy interaction is an asymmetric spiral arm, containing more molecular gas and exhibiting higher star formation rate (SFR) surface density than the two primary arms. Rotation curve analysis suggests that NGC 5430 and its satellite collided several Gyr ago. History of star formation was constrained by using SFRs that trace different timescales (infrared, radio continuum, and Hα). The collision occurred 5 -10 Myr ago, triggering a transient off-center starburst of Wolf-Rayet stars at the eastern bar end. In the past, the global SFR during the Wolf-Rayet starburst peaked at 35 M ⊙ yr −1 . At present, the merger-driven starburst is rapidly decaying and the current global SFR has decreased to the Galactic value. The SFR will continue to decay as suggested by the present amount of dense gas (traced by HCN (1-0)). Nonetheless, the global SFR is still dominated by the Wolf-Rayet region rather than the circumnuclear region. Compared with other barred galaxies, the circumnuclear region exhibits particularly low dense gas fraction, low star formation activity and high concentration of gas. Physical properties of the molecular gas are inferred by using the large velocity gradient (LVG) calculations. The initial mass ratio of the NGC 5430 and its satellite are suggested to be in the intermediate ratio range of 7:1-20:1.

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Gravitational Bar and Spiral Arm Torques fromK_s-band Observations and Implications for the Pattern Speeds

Cited by 81 publications

References 68 publications

Molecular gas in NUclei of GAlaxies (NUGA)

Molecular gas in NUclei of GAlaxies (NUGA)

Structure and star formation in disk galaxies

Constraints on the minor merging and star formation history of the Wolf–Rayet galaxy NGC 5430 through observations

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