A lopsided chemically distinct nucleus in NGC 5055

Afanasiev, V. L.; Сильченко, О. К.

doi:10.1051/0004-6361:20020571

Cited by 13 publications

(20 citation statements)

References 30 publications

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“…NGC 5055 shows strong activity inside 300 pc which can be interpreted either has an almost counter-rotating disk hosting a 9 ± 2 × 10 8 M object, or as a bipolar outflow. Gas kinematics alone tend to favor the bipolar outflow but peculiar stellar velocities in Afanasiev & Sil'chenko (2002) data would be more consistent with a rotating disk.…”

Section: Discussionmentioning

confidence: 92%

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Accurate determination of the mass distribution in spiral galaxies

Blais-Ouellette

Amram

Carignan

et al. 2004

A&A

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Abstract. High resolution Fabry-Perot data of six spiral galaxies are presented. Those data extend the previous sample of spiral galaxies studied with high resolution 3D spectroscopy to earlier morphological types. All the galaxies in the sample have available H I data at 21 cm from the VLA or Westerbork. Velocity fields are analyzed and Hα rotation curves are computed and compared to H I curves. The kinematics of NGC 5055 central regions are looked at more closely. Its peculiar kinematics can be interpreted either as a bipolar outflow or as a counter-rotating disk, possibly hosting a 9 ± 2 × 10 8 M compact object. Most of the Hα rotation curves present a significantly steeper inner slope than their H I counterparts. The 21 cm data thus seems affected by moderate to strong beam smearing. The beam smearing has an effect at higher scale-length/beam-width than previously thought (up to 20 km s −1 at a ratio of 8.5).

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Section: Discussionmentioning

confidence: 92%

“…Their long slit data did not allow the detection of the red component, but they probably detected the bright blue clump north-east of the center. However, Afanasiev & Sil'chenko (2002) note that a south-west anomaly (our red clump) is also present in their stellar velocities, a rather puzzling fact if the outflow interpretation is retained.…”

Section: Ngc 5055mentioning

confidence: 83%

Accurate determination of the mass distribution in spiral galaxies

Blais-Ouellette

Amram

Carignan

et al. 2004

A&A

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“…This is a key question for future research. Observationally, there are a number of candidate systems in addition to M31, as evidenced by apparently offset centres, ‘hollow’ central light profiles, double nuclei, or chemically distinct secondary nuclei (Thatte et al 2000; Afanasiev & Sil'chenko 2002; Lauer et al 2002, 2005; Debattista et al 2006), and NGC 4486b is another confirmed eccentric disc (Lauer et al 1996). There may be similar features in nuclear gas discs as well (Seth et al 2010).…”

Section: Discussionmentioning

confidence: 99%

The nuclear stellar disc in Andromeda: a fossil from the era of black hole growth

Hopkins

Quataert

2010

Monthly Notices of the Royal Astronomical Society: Letters

120

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The physics of angular momentum transport from galactic scales (∼10-100 pc) to much smaller radii is one of the outstanding problems in our understanding of the formation and evolution of supermassive black holes (BHs). Seemingly unrelated observations have discovered that there is a lopsided stellar disc of unknown origin orbiting the BH in M31, and possibly many other systems. We show that these nominally independent puzzles are in fact closely related. Multiscale simulations of gas inflow from galactic to BH scales show that when sufficient gas is driven towards a BH, gravitational instabilities form a lopsided, eccentric disc that propagates inwards from larger radii. The lopsided stellar disc exerts a strong torque on the remaining gas, driving inflows that fuel the growth of the BH and produce quasar-level luminosities. The same disc can produce significant obscuration along many sightlines and thus may be the putative 'torus' invoked to explain obscured active galactic nuclei and the cosmic X-ray background. The stellar relic of this disc is long lived and retains the eccentric pattern. Simulations that yield quasar-level accretion rates produce relic stellar discs with kinematics, eccentric patterns, precession rates and surface density profiles in reasonable agreement with observations of M31. The observed properties of nuclear stellar discs can thus be used to constrain the formation history of supermassive BHs.

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“…In this paper our spectroscopic technique is applied to derive the properties of the counter-rotating stellar populations of the Sa galaxy NGC 4138. The structure, kinematics, and dynamics of this nearby and relatively isolated galaxy were studied in detail by Jore et al (1996) and Afanasiev & Sil'chenko (2002). Optical images show no major peculiarities except for a narrow dust lane in the galactic disk.…”

Section: Introductionmentioning

confidence: 99%

The difference in age of the two counter-rotating stellar disks of the spiral galaxy NGC 4138

Pizzella

Morelli

Corsini

et al. 2014

A&A

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Context. Galaxies accrete material from the environment through acquisitions and mergers. These processes contribute to the galaxy assembly and leave their fingerprints on the galactic morphology, internal kinematics of gas and stars, and stellar populations. Aims. The Sa spiral NGC 4138 is known to host two counter-rotating stellar disks, with the ionized gas co-rotating with one of them. We measured the kinematics and properties of the two counter-rotating stellar populations to constrain their formation scenario. Methods. A spectroscopic decomposition of the observed major-axis spectrum was performed to disentangle the relative contribution of the two counter-rotating stellar and one ionized-gas components. The line-strength indices of the two counter-rotating stellar components were measured and modeled with single stellar population models that account for the α/Fe overabundance. Results. The counter-rotating stellar population is younger, marginally more metal poor, and more α-enhanced than the main stellar component. The younger stellar component is also associated with a star-forming ring. Conclusions. The different properties of the counter-rotating stellar components of NGC 4138 rule out the idea that they formed because of bar dissolution. Our findings support the results of numerical simulations in which the counter-rotating component assembled from gas accreted on retrograde orbits from the environment or from the retrograde merging with a gas-rich dwarf galaxy.

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A lopsided chemically distinct nucleus in NGC 5055

Cited by 13 publications

References 30 publications

Accurate determination of the mass distribution in spiral galaxies

Accurate determination of the mass distribution in spiral galaxies

The nuclear stellar disc in Andromeda: a fossil from the era of black hole growth

The difference in age of the two counter-rotating stellar disks of the spiral galaxy NGC 4138

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