WALLABY Early Science – IV. ASKAP H i imaging of the nearby galaxy IC 5201

ABSTRACT We present a Wide-field ASKAP L-Band Legacy All-sky Blind surveY (WALLABY) study of the nearby (vsys = 915 km s−1) spiral galaxy IC 5201 using the Australian Square Kilometre Array Pathfinder (ASKAP). IC 5201 is a blue, barred spiral galaxy that follows the known scaling relations between stellar mass, SFR, H i mass, and diameter. We create a four-beam mosaicked H i image cube from 175 h of observations made with a 12-antenna sub-array. The root mean square noise level of the cube is 1.7 mJy beam−1 per channel, equivalent to a column density of $N_{\rm H\, \small {I}}$ = 1.4 × 1020 cm−2 over 25 km s−1. We report nine extragalactic H i detections – five new H i detections including the first velocity measurements for two galaxies. These sources are IC 5201, three dwarf satellite galaxies, two galaxies, and a tidal feature belonging to the NGC 7232/3 triplet and two potential infalling galaxies to the triplet. There is evidence of a previous tidal interaction between IC 5201 and the irregular satellite AM 2220−460. A close fly-by is likely responsible for the asymmetric optical morphology of IC 5201 and warping its disc, resulting in the irregular morphology of AM 2220−460. We quantify the H i kinematics of IC 5201, presenting its rotation curve as well as showing that the warp starts at 14 kpc along the major axis, increasing as a function of radius with a maximum difference in position angle of 20°. There is no evidence of stripped H i, triggered or quenched star formation in the system as measured using DECam optical and GALEX UV photometry.

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A Possible Evolutionary Scenario for NGC 7217

Symposium - International Astronomical Union ◽

10.1017/s0074180900232580 ◽

1996 ◽

Vol 171 ◽

pp. 339-339 ◽

Cited By ~ 1

Author(s):

E. Athanassoula ◽

A. Bosma ◽

B. Guivarch ◽

L. Verdes-Montenegro

Keyword(s):

Spiral Galaxy ◽

Major Axis ◽

Position Angle ◽

Minor Axis ◽

Outer Ring ◽

Stellar Kinematics ◽

Evolutionary Scenario ◽

Nuclear Ring ◽

Oval Distortion

NGC 7217 is an ordinary spiral galaxy with three rings whose size ratios are such that they can be associated with resonances, as for barred spirals. From 21-cm HI line data and BVRI CCD-images of this galaxy we find (cf. Verdes-Montenegro et al. 1995) : 1) a nuclear ring strong in Hα, 2) an inner ring seen clearly in a B - I colour map, and 3) an outer ring, with blue colours and strong HI-emission. After deprojection the disk has a mean ellipticity of 0.04 ± 0.01, while the position angle of the deprojected galaxy changes suddenly at 65″ radius, where the minor axis becomes major axis. Thus a very mild oval distortion could exist, with the outer ring perpendicular to the oval. Merrifield and Kuijken (1994) find from the stellar kinematics that about 20 – 30 % of the stars are in retrograde orbits.

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Maximum parsimony analysis of the effect of the environment on the evolution of galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935604 ◽

2019 ◽

Vol 630 ◽

pp. A63 ◽

Cited By ~ 1

Author(s):

Didier Fraix-Burnet ◽

Mauro D’Onofrio ◽

Paola Marziani

Keyword(s):

Maximum Parsimony ◽

Maximum Parsimony Analysis ◽

Scaling Relations ◽

Wide Field ◽

Nearby Galaxy ◽

Tree Structures ◽

Cluster Galaxies ◽

Evolution Of Galaxies ◽

Two Samples ◽

Evolutionary Paths

Context. Galaxy evolution and the effect of the environment are most often studied using scaling relations or regression analyses around a given property. However, these approaches do not take into account the complexity of the physics of the galaxies and their diversity. Aims. We here investigate the effect of the cluster environment on the evolution of galaxies through multivariate, unsupervised classification and phylogenetic analyses applied to two relatively large samples from the Wide-field Nearby Galaxy-cluster Survey (WINGS), one of cluster members and one of field galaxies (2624 and 1476 objects, respectively). Methods. These samples are the largest ones ever analysed with a phylogenetic approach in astrophysics. To be able to use the maximum parsimony (cladistics) method, we first performed a pre-clustering in 300 clusters with a hierarchical clustering technique, before applying it to these pre-clusters. All these computations used seven parameters: B − V, log(Re), nV, ⟨μ⟩e, Hβ, D4000, and log(M*). Results. We have obtained a tree for the combined samples and do not find different evolutionary paths for cluster and field galaxies. However, the cluster galaxies seem to have accelerated evolution in the sense that they are statistically more diversified from a primitive common ancestor. The separate analyses show a hint of a slightly more regular evolution of the variables for the cluster galaxies, which may indicate they are more homogeneous compared to field galaxies in the sense that the groups of the latter appear to have more specific properties. On the tree for the cluster galaxies, there is a separate branch that gathers rejuvenated or stripped-off groups of galaxies. This branch is clearly visible on the colour-magnitude diagram, going back from the red sequence towards the blue one. On this diagram, the distribution and the evolutionary paths of galaxies are strikingly different for the two samples. Globally, we do not find any dominant variable able to explain either the groups or the tree structures. Rather, co-evolution appears everywhere, and could depend itself on environment or mass. Conclusions. This study is another demonstration that unsupervised machine learning is able to go beyond simple scaling relations by taking into account several properties together. The phylogenetic approach is invaluable in tracing the evolutionary scenarios and projecting them onto any bivariate diagram without any a priori modelling. Our WINGS galaxies are all at low redshift, and we now need to go to higher redshfits to find more primitive galaxies and complete the map of the evolutionary paths of present day galaxies.

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WINGS-SPE Spectroscopy in the WIde-field Nearby Galaxy-cluster Survey

Astronomy and Astrophysics ◽

10.1051/0004-6361:200810997 ◽

2009 ◽

Vol 495 (3) ◽

pp. 707-719 ◽

Cited By ~ 100

Author(s):

A. Cava ◽

D. Bettoni ◽

B. M. Poggianti ◽

W. J. Couch ◽

M. Moles ◽

...

Keyword(s):

Galaxy Cluster ◽

Wide Field ◽

Nearby Galaxy ◽

Cluster Survey

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Surface Photometry of Spiral Galaxy NGC 5005 and Elliptical Galaxy NGC 4278

Baghdad Science Journal ◽

10.21123/bsj.15.3.314-323 ◽

2018 ◽

Vol 15 (3) ◽

pp. 314-323

Author(s):

Baghdad Science Journal

Keyword(s):

Spiral Galaxy ◽

Surface Brightness ◽

Elliptical Galaxy ◽

Position Angle ◽

Sloan Digital Sky Survey ◽

Surface Photometry ◽

Contour Maps ◽

Sky Survey ◽

Flat Field ◽

The Galaxy

Two galaxies have been chosen, spiral galaxy NGC 5005 and elliptical galaxy NGC 4278 to study their photometric properties by using surface photometric techniques with griz-Filters. Observations are obtained from the Sloan Digital Sky Survey (SDSS). The data reduction of all images have done, like bias and flat field, by SDSS pipeline. The overall structure of the two galaxies (a bulge, a disk), together with isophotal contour maps, surface brightness profiles and a bulge/disk decomposition of the galaxy images were performed, although the disk position angle, ellipticity and inclination of the galaxies have been estimated.

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Barred Spiral Galaxy

The Encyclopedia of Astronomy and Astrophysics ◽

10.1888/0333750888/4689 ◽

2004 ◽

Keyword(s):

Spiral Galaxy ◽

Barred Spiral Galaxy

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Study of the Gas Kinematics in the Center of the Barred Spiral Galaxy NGC 4258.

International Astronomical Union Colloquium ◽

10.1017/s0252921100049678 ◽

1996 ◽

Vol 157 ◽

pp. 164-167

Author(s):

S. N. Dodonov

Keyword(s):

Spiral Galaxy ◽

Spatial Sampling ◽

Kinematic Structure ◽

Gas Kinematics ◽

Barred Spiral Galaxy ◽

Integral Field Spectrograph ◽

Integral Field

AbstractIntegral Field Spectrograph observations of southeast (SE) gas outflow in the center (11×13 arcsec) of NGC 4258 with spatial sampling 0.6 and 1.2 arcsec were made with the 6-m Telescope. Reconstructed spatial and kinematic structure of the SE outflow from 20-30 pc to 200-220 pc are presented.

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