Optical spectroscopy for a sample of southern binary galaxies

Silva, T. C. Couto da; Souza, R. E. de

doi:10.1051/0004-6361:20054444

Cited by 4 publications

(13 citation statements)

References 52 publications

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“…The central region is slightly bluer, contrary to the indication of the ESO-LV catalog. Nevertheless, our color map is in agreement with our spectroscopic data: this spiral exhibits strong central emissions and peculiar N spectra (Couto da Silva & de Souza 2006). There is a small variation in the PA distribution, ∆PA bd ∼ 4…”

Section: P112a (E1): the Isophotal Twisting Is ∼15supporting

confidence: 91%

“…The color map is slight bluish in the central region. This object is either a LINER or an Sy2 galaxy (Couto da Silva & de Souza 2006). A superposed and masked star in the inner side of the image did not allow a better analysis of this region.…”

Section: P112a (E1): the Isophotal Twisting Is ∼15mentioning

confidence: 98%

“…Columns 2-5 present the object identification from the ESO-LV catalogue (Lauberts & Valentijn 1989): identification, radial velocity, blue band total magnitude, and morphological type. Whenever possible, we complete the radial information in Col. 3 with data from other sources; in this column, CS indicates data from Couto da Silva & de Souza (2006); dCa, da Costa et al (1991);dCb, da Costa (1994); dCc, da dS, de Souza et al (1997); FJ, Fairall & Jones (1991); Lo, Loveday (1996); M, Mathewson et al (1992); R., Ratcliffe et al 1998;Sch., Schweizer (1987a,b); and SWa, Sekiguchi & Wolstencroft (1992). Until now, has been no radial velocity available for the object P151b; however, P151a was studied by Combes et al (1994) as a pair component, and according to Donzelli & Pastoriza (2000), P151 is a merging pair.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…For P130, we have the radial velocity information of only one of the components. We considered the pairs having ∆v ≥ 600 km s −1 as true binaries, according to Couto da Silva & de Souza (2006). Taking into account that 49 pairs have radial velocities for both components, we conclude that our sample contamination by non-pair members is ∼16%.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…In Couto da Silva & de Souza (2006), we present spectroscopic data for most, but not all, galaxies studied in this work, while some other pairs from the Soares et al (1995) list have information presented in our spectroscopy work. This occurred mainly due to observational weather conditions.…”

Section: Introductionmentioning

confidence: 99%

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Photometric study of a sample of southern binary galaxies

Silva

Souza²

2006

A&A

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Aims. This work exhibits the basic optical photometric data for a sample of 50 probable southern binary galaxies. Our sample covers a broad range of pair separations, stages of interaction, and morphologies. From the initial list of selected pairs, using spectroscopic data from the literature and our own data, we conclude that 84% of these systems are true binary galaxies. Methods. We present residual and asymmetric maps, R major semi-axis profiles of surface brightness, ellipticity, position-angle, harmonic Fourier coefficients of third and fourth order (b 3 and b 4 ) for 50 probable pairs, and B − R color maps for 47 of these pairs. For most galaxies, we present the profiles in two different ways, aiming to verify the influence of random errors on them. Results. We note that random errors in position-angle profiles are at least 2• , but a more significant result must take into account a variation larger than 11• for this distribution. Barred galaxies usually show a typical behavior in ellipticity and position-angle profiles: these profiles display variations when changing from a bar to a disk region. In some cases, the variations also occur along the bar. Some galaxies show distribution profiles that are common for their morphological type, and the interaction signature is only evidenced by their residual maps. Bars are usually redder and rings are bluer, when compared with the galaxy outskirts. Conclusions. Our data indicates that there is a connection between interaction strength and morphological distortions in binary galaxies. If we consider the projected separation of a pair as an indication of interaction strength, distortions such as displaced centers, anomalous shapes of spiral arms, and twistings of external regions are easily detected in some close pairs, although not all components of close pairs show this behavior. Our data suggests that besides interaction, other parameters, like orbital geometry and internal properties of galaxies, can stimulate binary galaxies' peculiarities.

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Section: P112a (E1): the Isophotal Twisting Is ∼15supporting

confidence: 91%

Section: P112a (E1): the Isophotal Twisting Is ∼15mentioning

confidence: 98%

Section: Observations and Data Reductionmentioning

confidence: 99%

Section: Observations and Data Reductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photometric study of a sample of southern binary galaxies

Silva

Souza²

2006

A&A

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Discovery of peculiar radio morphologies with ASKAP using unsupervised machine learning

Gupta

Huynh

Norris

et al. 2022

Publ. Astron. Soc. Aust.

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We present a set of peculiar radio sources detected using an unsupervised machine learning method. We use data from the Australian Square Kilometre Array Pathfinder (ASKAP) telescope to train a self-organizing map (SOM). The radio maps from three ASKAP surveys, Evolutionary Map of Universe pilot survey (EMU-PS), Deep Investigation of Neutral Gas Origins pilot survey (DINGO), and Survey With ASKAP of GAMA-09 + X-ray (SWAG-X), are used to search for the rarest or unknown radio morphologies. We use an extension of the SOM algorithm that implements rotation and flipping invariance on astronomical sources. The SOM is trained using the images of all ‘complex’ radio sources in the EMU-PS which we define as all sources catalogued as ‘multi-component’. The trained SOM is then used to estimate a similarity score for complex sources in all surveys. We select 0.5% of the sources that are most complex according to the similarity metric and visually examine them to find the rarest radio morphologies. Among these, we find two new odd radio circle (ORC) candidates and five other peculiar morphologies. We discuss multiwavelength properties and the optical/infrared counterparts of selected peculiar sources. In addition, we present examples of conventional radio morphologies including: diffuse emission from galaxy clusters, and resolved, bent-tailed, and FR-I and FR-II type radio galaxies. We discuss the overdense environment that may be the reason behind the circular shape of ORC candidates.

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The 2mass Redshift Survey—description and Data Release

Huchra

Macri

Masters

et al. 2012

ApJS

672

675

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We present the results of the 2MASS Redshift Survey (2MRS), a ten-year project to map the full three-dimensional distribution of galaxies in the nearby Universe. The 2 Micron All-Sky Survey (2MASS) was completed in 2003 and its final data products, including an extended source catalog (XSC), are available on-line. The 2MASS XSC contains nearly a million galaxies with K s ≤ 13.5 mag and is essentially complete and mostly unaffected by interstellar extinction and stellar confusion down to a galactic latitude of |b| = 5 • for bright galaxies. Near-infrared wavelengths are sensitive to the old stellar populations that dominate galaxy masses, making 2MASS an excellent starting point to study the distribution of matter in the nearby Universe.We selected a sample of 44,599 2MASS galaxies with K s ≤ 11.75 mag and |b| ≥ 5 • (≥ 8 • towards the Galactic bulge) as the input catalog for our survey. We obtained spectroscopic observations for 11,000 galaxies and used previously-obtained velocities for the remainder of the sample to generate a redshift catalog that is 97.6% complete to well-defined limits and covers 91% of the sky. This provides an unprecedented census of galaxy (baryonic mass) concentrations within 300 Mpc.Earlier versions of our survey have been used in a number of publications that have studied the bulk motion of the Local Group, mapped the density and peculiar velocity fields out to 50 h −1 Mpc, detected galaxy groups, and estimated the values of several cosmological parameters.Additionally, we present morphological types for a nearly-complete sub-sample of 20,860 galaxies with K s ≤ 11.25 mag and |b| ≥ 10 • .

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Optical spectroscopy for a sample of southern binary galaxies

Cited by 4 publications

References 52 publications

Photometric study of a sample of southern binary galaxies

Photometric study of a sample of southern binary galaxies

Discovery of peculiar radio morphologies with ASKAP using unsupervised machine learning

The 2mass Redshift Survey—description and Data Release

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