scholarly journals KPG 390: A pair of trailing spirals.

2010 ◽  
Vol 6 (S271) ◽  
pp. 127-134
Author(s):  
P. Repetto ◽  
M. Rosado ◽  
R. Gabbasov ◽  
I. Fuentes-Carrera
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Rotation Curve ◽  
Velocity Fields ◽  
Minor Axis ◽  
The Other ◽  
Kinematic Parameters ◽  
First Case ◽  
Fabry Perot ◽  
Different Types

AbstractIn this study we present scanning Fabry-Perot Hα observations of the isolated interacting galaxy pair NGC 5278/79. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. These kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine univocally that both components of the interacting pair are trailing spirals. We have also estimated the mass of NGC 5278 fitting its rotation curve with a disk-halo component. We have tested three different types of halo (pseudo-isothermal, Hernquist and Navarro Frenk White) and we have obtained that the rotation curve can be fitted either with a pseudo-isothermal, an Hernquist halo or a Navarro Frenk White halo component, although in the first case the amount of dark matter required is about ten times smaller than for the other two halo distributions.

scholarly journals Dark Matter Distribution in Nearby Galaxies

2004 ◽  
Vol 220 ◽  
pp. 327-328
Author(s):  
Olivia Garrido ◽  
Philippe Amram ◽  
Claude Carignan ◽  
Sébastien Blais-Ouellette ◽  
Michel Marcelin ◽  
...  
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
Mass Distribution ◽  
Rotation Curve ◽  
Velocity Fields ◽  
Constant Density ◽  
Matter Distribution ◽  
Fabry Perot ◽  
Nearby Galaxies ◽  
Dark Matter Distribution

We present results obtained from a study of the mass distribution of 24 galaxies observed using Fabry-Pérot techniques, as part of the GHASP survey (see Russeil et al., this meeting). For each galaxy, we combined high resolution Hα rotation curves derived from 2-D velocity fields, with low resolution HI data, in order to determine accurately the inner slope of the rotation curve which strongly constrains the distribution of matter. Our work suggests the existence of a constant density core in the center of the dark halos.

scholarly journals Slowly rotating Bose–Einstein condensate compared with the rotation curves of 12 dwarf galaxies

2020 ◽  
Vol 633 ◽  
pp. A75
Author(s):  
E. Kun ◽  
Z. Keresztes ◽  
L. Á. Gergely
Keyword(s):  
Dark Matter ◽  
Angular Velocity ◽  
Surface Brightness ◽  
Rotation Curve ◽  
Dwarf Galaxies ◽  
Finite Size ◽  
Einstein Condensate ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Model Fits

Context. The high plateaus of the rotation curves of spiral galaxies suggest either that there is a dark component or that the Newtonian gravity requires modifications on galactic scales to explain the observations. We assemble a database of 12 dwarf galaxies, for which optical (R-band) and near-infrared (3.6 μm) surface brightness density together with spectroscopic rotation curve data are available, in order to test the slowly rotating Bose–Einstein condensate (BEC) dark matter model. Aims. We aim to establish the angular velocity range compatible with observations, bounded from above by the requirement of finite-size halos, to check the model fits with the dataset, and the universality of the BEC halo parameter ℛ. Methods. We constructed the spatial luminosity density of the stellar component of the dwarf galaxies based on their 3.6 μm and R-band surface brightness profiles, assuming an axisymmetric baryonic mass distribution with arbitrary axis ratio. We built up the gaseous component of the mass by employing an inside-truncated disk model. We fitted a baryonic plus dark matter combined model, parametrized by the M/L ratios of the baryonic components and parameters of the slowly rotating BEC (the central density ρc, size of the BEC halo ℛ in the static limit, angular velocity ω) to the rotation curve data. Results. The 3.6 μm surface brightness of six galaxies indicates the presence of a bulge and a disk component. The shape of the 3.6 μm and R-band spatial mass density profiles being similar is consistent with the stellar mass of the galaxies emerging wavelength-independent. The slowly rotating BEC model fits the rotation curve of 11 galaxies out of 12 within the 1σ significance level, with the average of ℛ as 7.51 kpc and standard deviation of 2.96 kpc. This represents an improvement over the static BEC model fits, also discussed. For the 11 best-fitting galaxies the angular velocities allowing for a finite-size slowly rotating BEC halo are less then 2.2 × 10−16 s−1.For a scattering length of the BEC particle of a ≈ 106 fm, as allowed by terrestrial laboratory experiments, the mass of the BEC particle is slightly better constrained than in the static case as m ∈ [1.26 × 10−17 ÷ 3.08 × 10−17] (eV c−2).

scholarly journals The universal rotation curve of low surface brightness galaxies – IV. The interrelation between dark and luminous matter

2019 ◽  
Vol 490 (4) ◽  
pp. 5451-5477 ◽  
Author(s):  
Chiara Di Paolo ◽  
Paolo Salucci ◽  
Adnan Erkurt
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Rotation Curve ◽  
High Surface ◽  
Dark Matter Halo ◽  
Rotation Curves ◽  
Central Surface ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Lsb Galaxies

ABSTRACT We investigate the properties of the baryonic and the dark matter components in low surface brightness (LSB) disc galaxies, with central surface brightness in the B band $\mu _0 \ge 23 \, \mathrm{mag \, arcsec}^{-2}$. The sample is composed of 72 objects, whose rotation curves show an orderly trend reflecting the idea of a universal rotation curve (URC) similar to that found in the local high surface brightness (HSB) spirals in previous works. This curve relies on the mass modelling of the co-added rotation curves, involving the contribution from an exponential stellar disc and a Burkert cored dark matter halo. We find that the dark matter is dominant especially within the smallest and less luminous LSB galaxies. Dark matter haloes have a central surface density $\Sigma _0 \sim 100 \, \mathrm{M}_{\odot } \, \mathrm{pc}^{-2}$, similar to galaxies of different Hubble types and luminosities. We find various scaling relations among the LSBs structural properties which turn out to be similar but not identical to what has been found in HSB spirals. In addition, the investigation of these objects calls for the introduction of a new luminous parameter, the stellar compactness C* (analogously to a recent work by Karukes & Salucci), alongside the optical radius and the optical velocity in order to reproduce the URC. Furthermore, a mysterious entanglement between the properties of the luminous and the dark matter emerges.

scholarly journals Hα KINEMATICS OF THE ISOLATED INTERACTING GALAXY PAIR KPG 486 (NGC 6090)

2020 ◽  
Vol 56 (1) ◽  
pp. 71-83
Author(s):  
M. M. Sardaneta ◽  
M. Rosado ◽  
M. Sánchez-Cruces
Keyword(s):  
Velocity Field ◽  
Emission Line ◽  
Kinematic Analysis ◽  
Rotation Curve ◽  
Dynamic Behaviour ◽  
Hydrogen Gas ◽  
Kinematic Parameters ◽  
Optical Images ◽  
Fabry Perot ◽  
Hα Emission

In optical images, the barely studied isolated interacting galaxy pair KPG 486 (NGC 6090) displays similar features to the Antennae (NGC 4038/39) galaxy pair. To compare the distribution of ionized hydrogen gas, morphology and kinematic and dynamic behaviour of both galaxy pairs, we present observations in the Hα emission line of NGC 6090 acquired with the scanning Fabry-Perot interferometer, PUMA. For each galaxy in NGC 6090 we obtained several kinematic parameters, its velocity field and its rotation curve. We also analysed some of the perturbations induced by their encounter. We verified the consistency of our results by comparing them with kinematic results from the literature. The comparison of our results on NGC 6090 with those obtained in a previous similar kinematic analysis of the Antennae highlighted great differences between these galaxy pairs.

scholarly journals A 3D Optical Spectroscopy Study of Low Surface Brightness Galaxies

2004 ◽  
Vol 220 ◽  
pp. 333-334
Author(s):  
L. Chemin ◽  
P. Amram ◽  
C. Carignan ◽  
C. Balkowski ◽  
W. van Driel ◽  
...  
Keyword(s):  
Emission Line ◽  
Optical Spectroscopy ◽  
Surface Brightness ◽  
Velocity Fields ◽  
Spectroscopy Study ◽  
Fabry Perot ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We present Hα emission line velocity fields of two Low Surface Brightness galaxies (LSBs) - UGC 628 and UGC 5005 - obtained using Fabry-Perot (FP) interferometry observations at the Canada-France-Hawaii telescope. Our goal is to study the dynamics of LSBs.

The Descriptive-Normative Dichotomy and the So Called Naturalistic Fallacy

2016 ◽  
Vol 38 (2) ◽  
Author(s):  
Edgar Morscher
Keyword(s):  
Naturalistic Fallacy ◽  
The Other ◽  
Final Part ◽  
Philosophical Perspective ◽  
Clear Cut ◽  
First Case ◽  
Different Types ◽  
Normative Discourse

AbstractInvestigating the genesis and justification of norms in a theoretical way requires a clear-cut distinction between normative and descriptive discourse. From a philosophical perspective, the descriptive-normative dichotomy can itself be understood either in a descriptive (or ‘reportive’) or in an normative (or ‘stipulative’) way. In the first case such a dichotomy is understood as the factual border between descriptive and normative discourse in a given language; exploring this border is a hermeneutic enterprise. In the other case it is understood as a boundary between descriptive and normative discourse to be implanted in a language which is developed in order to fit certain purposes, in particular theoretical purposes; this implanting procedure is a matter of regimentation. In this paper I will deal shortly with the first question of hermeneutics and then in more detail with the second question of regimentation. In the final part of the paper I will distinguish different types of naturalistic fallacies resulting from disregarding descriptive-normative dichotomies.

scholarly journals 2D kinematics of the edge-on spiral galaxy ESO 379-006

2012 ◽  
Vol 8 (S295) ◽  
pp. 234-235
Author(s):  
M. Rosado ◽  
R. F. Gabbasov ◽  
P. Repetto ◽  
I. Fuentes-Carrera ◽  
P. Amram ◽  
...  
Keyword(s):  
Velocity Field ◽  
Radial Velocity ◽  
Rotation Curve ◽  
Minor Axis ◽  
Ionized Gas ◽  
Diffuse Ionized Gas ◽  
Fabry Perot ◽  
The Galaxy ◽  
Rotation Motion

AbstractWe present a kinematical study of the marginally edge-on galaxy ESO 379-006. With Fabry-Perot spectroscopy at Hα we obtain velocity maps, the radial velocity field, and position-velocity diagrams parallel to the major and to the minor axis of the galaxy. We build the rotation curve of the galaxy and discuss the role of projection effects. The twisting of isovelocities in the radial velocity field of the disk of ESO 379-006 as well as a kinematical asymmetry found in the position-velocity diagrams parallel to the minor axis suggest the existence of non-circular motions that can be modeled by including a radial inflow besides the rotation motion. Extraplanar Diffuse Ionized gas was detected in this galaxy both from the images and from its kinematics. It is possible that the diffuse gas is lagging in rotation.

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

A NEW APPROACH TO THE STUDY OF COORDINATIVE CONSTRUCTIONS

2019 ◽  
pp. 175-187
Author(s):  
Anna Varnayeva
Keyword(s):  
Characteristic Property ◽  
Mathematical Concept ◽  
The Other ◽  
New Approach ◽  
Logical Aspect ◽  
First Case

Coordinative constructions are traditionally opposed to subordinative constructions. However, this opposition comes down to denial of dependence in coordinative constructions. Thereby the parity of these two constructions does not come to light: subordinative construction can be described without coordinative one. This situation is not improved by detection of a coordinative triangle in all coordinative constructions. The article shows a new approach in the study of coordinative constructions: a coordinative construction is a system; there are not only specific relations – a coordinative triangle, – but also specific elements. Novelty of the study consists in the address to extralinguistic facts, viz. a mathematical concept of a set and its elements. There are a lot of similarities between them. A set in mathematics includes generalizing elements and the composed row in coordinative constructions; in the first case the set is not partitioned, in the second case it is partitioned. In mathematics equivalent components in coordinative constructions correspond to the set elements. A characteristic property in mathematics is homogeneity in coordinative constructions and etc. It is firstly demonstrated, that coordinative and subordinative constructions are correlative and the study of one construction is impossible without the study of the other one. Their parity is shown in coordinative constructions with elements of one set, in subordinative ones with elements of different sets. Cf.: roses and tulips –red roses. In the coordinatiму construction elements of one set are called: «flowers »; in the subordinative construction there are elements of different sets: «flowers » and «colors». It should be noted that the mathematical concept of a set relates to so called logical aspect in linguistics or thinking about reality.

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