scholarly journals The Dynamical Evolution of Centaurus A

1996 ◽  
Vol 171 ◽  
pp. 463-463
Author(s):  
S.G. Vine ◽  
R.C. Thomson
Keyword(s):  
Simulation Model ◽  
Spiral Galaxy ◽  
Surface Brightness ◽  
Dynamical Evolution ◽  
Interacting Galaxies ◽  
Dust Lane ◽  
Preliminary Results ◽  
Axis Of Rotation ◽  
Low Surface Brightness ◽  
Centaurus A

Centaurus A (NGC 5128) is a nearby Giant Elliptical (3.5Mpc, 1012 Solar Masses). It has a prominent dust-lane which has an axis of rotation orientated differently from that of the underlying galaxy. Close to it are two galaxies: NGC 5237 – a dwarf elliptical, and Fourcade-Figueroa – a low surface brightness irregular. We are investigating whether these three objects are the resulting components of a grazing interaction between a Giant Elliptical and a less massive spiral galaxy. We have conducted n-body simulations, modelling all components of the two original interacting galaxies. Preliminary results show that Cen A, its dust-lane, and NGC 5237 are consistent with this simulation model. Centaurus A exhibits many other features which are also indicative of a past interaction.

scholarly journals Radio Observations of AGN in Low Surface Brightness Galaxies

2007 ◽  
Vol 3 (S244) ◽  
pp. 352-353
Author(s):  
M. Das ◽  
S. S. McGaugh ◽  
N. Kantharia ◽  
S. N. Vogel
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Low Frequency ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Preliminary Results ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Lsb Galaxies ◽  
Extended Emission

AbstractWe present preliminary results of a study of the low frequency radio continuum emission from the nuclei of Giant Low Surface Brightness (LSB) galaxies. We have mapped the emission and searched for extended features such as radio lobes/jets associated with AGN activity. LSB galaxies are poor in star formation and generally less evolved compared to nearby bright spirals. This paper presents low frequency observations of 3 galaxies; PGC 045080 at 1.4 GHz, 610 MHz, 325MHz, UGC 1922 at 610 MHz and UGC 6614 at 610 MHz. The observations were done with the GMRT. Radio cores as well as extended structures were detected and mapped in all three galaxies; the extended emission may be assocated with jets/lobes associated with AGN activity. Our results indicate that although these galaxies are optically dim, their nuclei can host AGN that are bright in the radio domain.

scholarly journals The haloes and environments of nearby galaxies (HERON) – II. The outer structure of edge-on galaxies

2020 ◽  
Vol 494 (2) ◽  
pp. 1751-1770 ◽  
Author(s):  
Aleksandr Mosenkov ◽  
R Michael Rich ◽  
Andreas Koch ◽  
Noah Brosch ◽  
David Thilker ◽  
...  
Keyword(s):  
Surface Brightness ◽  
3D Model ◽  
Interacting Galaxies ◽  
Deep Imaging ◽  
Low Surface Brightness ◽  
The Galaxy ◽  
Nearby Galaxies

ABSTRACT The haloes and environments of nearby galaxies (HERON) project is aimed at studying haloes and low surface brightness (LSB) details near galaxies. In this second HERON paper, we consider in detail deep imaging (down to surface brightness of ∼28 mag arcsec−2 in the r band) for 35 galaxies, viewed edge-on. We confirm a range of LSB features previously described in the literature but also report new ones. We classify the observed outer shapes of the galaxies into three main types (and their prototypes): disc/diamond-like (NGC 891), oval (NGC 4302), and boxy (NGC 3628). We show that the shape of the outer disc in galaxies does not often follow the general 3D model of an exponential disc: 17 galaxies in our sample exhibit oval or even boxy isophotes at the periphery. Also, we show that the less flattened the outer disc, the more oval or boxy its structure. Many galaxies in our sample have an asymmetric outer structure. We propose that the observed diversity of the galaxy outer shapes is defined by the merger history and its intensity: if no recent multiple minor or single major merging took place, the outer shape is diamond-like or discy. On the contrary, interacting galaxies show oval outer shapes, whereas recent merging appears to transform the outer shape to boxy.

Precession in the Jet of NGC 5128 (Centaurus A)

1983 ◽  
Vol 5 (2) ◽  
pp. 241-247 ◽  
Author(s):  
R.F. Haynes ◽  
R.D. Cannon ◽  
R.D. Ekers
Keyword(s):  
Radio Source ◽  
Spiral Galaxy ◽  
Dust Lane ◽  
Double Radio Source ◽  
Centaurus A

NGC 5128, identified with the radio source Centaurus A by Bolton et al. (1949), is a remarkable galaxy which appears to consist of an elliptical or SO galaxy crossed by a strong dust lane. The early idea that this represented a pair of colliding galaxies (Baade and Minkowski 1954) powering the extended double radio source fell out of favour but has recently been revived (Malin et al. 1983) in the light of extensive kinematic evidence. However, the interpretation of the data is not yet complete, and it has also been suggested recently that NGC 5128 is really a spiral galaxy with a spectacularly large bulge (Marcelin et al. 1982).

scholarly journals Optical Counterparts to Galaxies in the Cen A Group Discovered by HIPASS

1999 ◽  
Vol 16 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Patricia M. Knezek
Keyword(s):  
Surface Brightness ◽  
Survey Area ◽  
Late Type ◽  
New Members ◽  
Low Surface Brightness ◽  
Survey Technique ◽  
Group Members ◽  
The Subject ◽  
Centaurus A

AbstractWe have completed a 21-cm survey of a 600 square degree region of the Centaurus A group of galaxies at a redshift of ∼500 km s−1 as part of a larger survey of the entire southern sky. This group of galaxies was recently the subject of a separate and thorough optical survey (Côté et al. 1997), and thus presented an ideal comparison for us to test the survey performance. We have identified 10 new group members to add to the 21 already known in our survey area. Six of the new members are previously uncatalogued galaxies, while four were catalogued but assumed not to be group members. Including the seven known members outside of our survey area, this brings the total known number of Cen A members to 38. All of the new HI detections have optical counterparts, most being intrinsically very faint (MB > –13·0), late-type low surface brightness dwarfs. Most of the new members have HI masses only a few times our survey limit of 107M☉ at an assumed distance for the group of 3·5 Mpc, and are extremely gas-rich, with a median MHI/LB > 1. Our limiting HI sensitivity was actually slightly worse than the HI follow-up observations of the Côté et al. optical survey, yet we have already increased the known number of group members by 50% using an HIsurvey technique. While we have increased the known number of members by ∼50%, these new members contribute <4% to its light.

The Structure of the Superthin Spiral Galaxy UGC7321

1999 ◽  
Vol 171 ◽  
pp. 207-209
Author(s):  
L.D. Matthews ◽  
J.S. Gallagher ◽  
W. van Driel
Keyword(s):  
Star Formation ◽  
Spiral Galaxy ◽  
Surface Brightness ◽  
Scale Height ◽  
Vertical Scale ◽  
Low Surface Brightness ◽  
Galaxy Disk ◽  
Color Gradients

AbstractUGC 7321 is an edge-on low surface brightness (LSB) spiral galaxy with a number of extraordinary properties. Its vertical scale height (~70 pc) is one of the smallest ever measured for a galaxy disk. Its disk also exhibits strong vertical and radial color gradients. UGC 7321 appears to be an extremely unevolved galaxy in both a dynamical and in a star-formation sense.

scholarly journals Central DM density cuspiness in LSB's: a stellar kinematics approach

2004 ◽  
Vol 220 ◽  
pp. 337-338 ◽  
Author(s):  
A. Pizzella ◽  
E.M. Corsini ◽  
F. Bertola ◽  
L. Coccato ◽  
J. Magorrian ◽  
...  
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Stellar Kinematics ◽  
Ionized Gas ◽  
Dynamical Modeling ◽  
Preliminary Results ◽  
Spectroscopic Observations ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We present preliminary results from spectroscopic observations of a sample of 11 low surface brightness galaxies (LSB). We measured the stellar and gaseous kinematics along their major and minor axes. Such information will allow us to accurately investigate the dark matter (DM) content within their optical regions, providing further constraints on the predictions of standard CDM models. Although dynamical modeling is still in progress, our observations already show that the derived stellar kinematics is more regular than the ionized gas one, which often shows evidence for non-circular and asymmetric motions.

scholarly journals Gasdynamics and Starbursts in Interacting Galaxies

1999 ◽  
Vol 186 ◽  
pp. 205-212 ◽  
Author(s):  
J. Christopher Mihos
Keyword(s):  
Surface Brightness ◽  
High Surface ◽  
Disk Surface ◽  
Interacting Galaxies ◽  
Host Galaxies ◽  
Direct Function ◽  
High Surface Brightness ◽  
Low Surface Brightness ◽  
The Stability ◽  
Low Surface Brightness Galaxies

The onset of gaseous inflows and central activity in interacting galaxies is driven largely by induced bars in the host galaxies. The stability of galaxies against growing bar modes is a direct function of their structural properties — galaxies with central bulges or low disk surface densities are more stable against central starbursts than are bulgeless or disk-dominated systems. Low surface brightness galaxies prove less prone to bar formation and central starbursts than do normal high surface brightness galaxies. This stability of LSB disks also resolves many of the dynamical pitfalls encountered when attempting to link poststarburst “E+A” galaxies to interactions involving normal high surface brightness galaxy progenitors.

Discovery of a Nearby Low Surface Brightness Spiral Galaxy

1999 ◽  
Vol 117 (1) ◽  
pp. 194-201 ◽  
Author(s):  
W. B. Burton ◽  
R. Braun ◽  
R. A. M. Walterbos ◽  
C. G. Hoopes
Keyword(s):  
Spiral Galaxy ◽  
Surface Brightness ◽  
Low Surface Brightness

scholarly journals Evolution of Galaxies in Triaxial Halos with Figure Rotation

2004 ◽  
Vol 220 ◽  
pp. 299-304
Author(s):  
Kenji Bekki ◽  
K. C. Freeman
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Dynamical Evolution ◽  
Dark Matter Halo ◽  
Disk Galaxies ◽  
Formation Processes ◽  
Dark Matter Halos ◽  
Low Surface Brightness ◽  
Figure Rotation ◽  
Bar Formation

Firstly, we demonstrate that unusually large outer HI spiral arms observed in NGC 2915 can form in an extended gas disk embedded in a massive triaxial dark matter halo with slow figure rotation, through the strong gravitational torque of the rotating halo. Secondly, we show that the figure rotation of a triaxial dark matter halo can influence dynamical evolution of disk galaxies by using fully self-consistent numerical simulations. We particularly describe the formation processes of “halo-triggered” bars in thin galactic disks dominated by dark matter halos with figure rotation and discuss the origin of stellar bars in low luminosity, low surface brightness (LSB) disk galaxies. Thirdly, we provide several implications of the present numerical results in terms of triggering mechanism of starbursts in galaxies and stellar bar formation in high redshifts.

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