scholarly journals Planetary nebulae as kinematic tracers of galaxy stellar halos

2016 ◽  
Vol 12 (S323) ◽  
pp. 271-278
Author(s):  
Lodovico Coccato
Keyword(s):  
Surface Brightness ◽  
Spiral Galaxies ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Early Type ◽  
Dynamical Properties ◽  
Bright Emission

AbstractThe kinematic and dynamical properties of galaxy stellar halos are difficult to measure because of the faint surface brightness that characterizes these regions. Spiral galaxies can be probed using the radio Hiemission; on the contrary, early-type galaxies contain less gas, therefore alternative kinematic tracers need to be used. Planetary nebulae (PNe) can be easily detected far out in the halo thanks to their bright emission lines. It is therefore possible to map the halo kinematics also in early-type galaxies, typically out to 5 effective radii or beyond. Thanks to the recent spectroscopic surveys targeting extra-galactic PNe, we can now rely on a few tens of galaxies where the kinematics of the stellar halos are measured. Here, I will review the main results obtained in this field in the last decades.

Planetary nebulae as kinematic tracers of galaxy halos

2015 ◽  
Vol 11 (A29B) ◽  
pp. 20-25 ◽  
Author(s):  
Lodovico Coccato ◽  
Keyword(s):  
Surface Brightness ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Planetary Nebulae ◽  
Early Type ◽  
Number Density ◽  
Host Galaxies ◽  
Galaxy Halos ◽  
Radial Profiles ◽  
Dynamical Properties

AbstractThe kinematics and dynamical properties of galaxy stellar halos are difficult to measure, given the faint surface brightness that characterizes these regions. Gas-rich systems such as spiral galaxies can be probed using the radio Hi emission. Early-type galaxies contain less gas, therefore alternative kinematic tracers need to be used. Planetary Nebulae (PNe) can be easily detected far out in the halo thanks to their bright [O iii] emission at 5007 Å. It is therefore possible to map the halo kinematics also in early-type galaxies, typically out to 5 effective radii or beyond. Thanks to the recent spectroscopic surveys targeting extra-galactic PNe, we can now rely on few tens of galaxies where the kinematics of the stellar halos are measured. I will discuss the most important results: (a) the relation of the stellar surface brightness and the PNe number density; (b) the velocity and velocity dispersion two-dimensional fields; (c) the radial profiles of angular momentum; and (d) the relation between the derived kinematics physical properties of the host galaxies.

scholarly journals Planetary nebulae as kinematic tracers of galaxy halos

2015 ◽  
Vol 11 (A29B) ◽  
Author(s):  
Lodovico Coccato ◽  
Keyword(s):  
Surface Brightness ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Planetary Nebulae ◽  
Early Type ◽  
Number Density ◽  
Host Galaxies ◽  
Galaxy Halos ◽  
Radial Profiles ◽  
Dynamical Properties

AbstractThe kinematics and dynamical properties of galaxy stellar halos are difficult to measure, given the faint surface brightness that characterizes these regions. Gas-rich systems such as spiral galaxies can be probed using the radio Hi emission. Early-type galaxies contain less gas, therefore alternative kinematic tracers need to be used. Planetary Nebulae (PNe) can be easily detected far out in the halo thanks to their bright [Oiii] emission at 5007 Å. It is therefore possible to map the halo kinematics also in early-type galaxies, typically out to 5 effective radii or beyond. Thanks to the recent spectroscopic surveys targeting extra-galactic PNe, we can now rely on few tens of galaxies where the kinematics of the stellar halos are measured. I will discuss the most important results: (a) the relation of the stellar surface brightness and the PNe number density; (b) the velocity and velocity dispersion two-dimensional fields; (c) the radial profiles of angular momentum; and (d) the relation between the derived kinematics physical properties of the host galaxies.

scholarly journals Stellar systems following the R1/m luminosity law

2019 ◽  
Vol 626 ◽  
pp. A110 ◽  
Author(s):  
Maarten Baes ◽  
Luca Ciotti
Keyword(s):  
Entire Range ◽  
Surface Brightness ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Analytical Techniques ◽  
The Other ◽  
Early Type ◽  
Dispersion Tensor ◽  
Low Mass ◽  
Dynamical Properties

The Sérsic or R1/m model has become the de facto standard model to describe the surface brightness profiles of early-type galaxies and the bulges of spiral galaxies. The photometric, intrinsic, and dynamical properties of this model have been investigated, but mainly for fairly large Sérsic indices m. For small values of m, appropriate for low-mass and dwarf ellipticals, a detailed investigation of these properties is still lacking. In this study, we used a combination of numerical and analytical techniques to investigate the Sérsic model over the entire range of Sérsic parameters, focussing on the small m regime, where a number of interesting and surprising properties are found. For all values m <  1, the model is characterised by a finite central luminosity density, and for m < 1/2, even a central depression in the luminosity density profile. This behaviour translates to the dynamical properties: we show that all Sérsic models with m ⩾ 1/2 can be supported by an isotropic velocity dispersion tensor, and that these isotropic models are stable to both radial and non-radial perturbations. The models with m < 1/2, on the other hand, cannot be supported by an isotropic velocity dispersion tensor.

scholarly journals Polarized Line Profiles in Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 231-231
Author(s):  
J.R. Walsh ◽  
R.E.S. Clegg
Keyword(s):  
Indirect Evidence ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Symmetric Pattern ◽  
Near Ir ◽  
First Results ◽  
The Face ◽  
Polarization Profiles ◽  
Ir Emission ◽  
Bright Emission

There is much direct and indirect evidence for the presence of dust in Planetary Nebulae (PN): variations in extinction across the face of the nebulae; IR emission with strong 25 and 60μm fluxes; broad near-IR emission lines of Silicate, SiC and PAH grains; optically thick lines, such as [C IV]1550Å, have lower strength on account of the increased path length due to dust scattering; a centro-symmetric pattern of polarization vectors in a few PN (Leroy et al., A&A, 160, 171, 1986). An observational programme has begun to study the polarization profiles of bright emission lines in PN arising from dust scattering within the nebulae. The first results are discussed.

scholarly journals Recombination line abundances in the winds of the [WC] Wolf-Rayet stars

1997 ◽  
Vol 180 ◽  
pp. 112-113
Author(s):  
R. L. Kingsburgh ◽  
I. Dashevsky ◽  
M. J. Barlow
Keyword(s):  
Stellar Wind ◽  
Planetary Nebulae ◽  
Central Star ◽  
Emission Lines ◽  
Early Type ◽  
Recombination Line ◽  
Optical Spectrophotometry ◽  
Central Stars ◽  
Line Analysis

We present a preliminary abundance analysis, utilising recombination theory, for the [WC] Wolf-Rayet central stars of the planetary nebulae NGC 6751 and NGC 6905. This analysis is based on optical spectrophotometry of a sample of [WC] stars which show a strong O vi 3811, 34 å feature in emission. We have performed a recombination line analysis of stellar wind emission lines which are judged to be optically thin, in order to derive relative C, O and He abundances. We also present a comparison of the derived wind abundances with those of Population I WO stars. For the [WC 4] central star of NGC 6751, we have derived C/He = 0.35 and C/O = 4.2, by number. And for the [WC 3] central star of NGC 6905, we have derived C/He = 0.36 and C/O< 12. These surface abundances are comparable to the abundances that have been derived for early type [WC] stars via more complex NLTE modelling (e.g. Koesterke & Hamann 1996).

scholarly journals Colour (≈Age?) Gradients in Spiral Galaxies

1996 ◽  
Vol 171 ◽  
pp. 358-358
Author(s):  
Roelof S. de Jong
Keyword(s):  
Surface Brightness ◽  
Stellar Population ◽  
Spiral Galaxies ◽  
List Type ◽  
Type Number ◽  
Population Synthesis ◽  
Early Type ◽  
Stellar Population Synthesis ◽  
Colour Distribution ◽  
Best Fit

A sample of 86 galaxies was imaged in the B, V, R, I, H and K passbands to study their light and colour distribution as function of radius (de Jong & van der Kruit 1994). The radial colour gradients were compared with new dust models, which included both absorption and scattering, and with the stellar population synthesis models of Bruzual & Chariot (1993) and Worthey (1994). By requiring that the models had to fit all six passband photometry at the same time, the relative effects of dust, stellar age and stellar metallicity could be seperated (de Jong 1995a, 1995b). The main results from this investigation are: –All galaxies become bluer with increasing radius. The colour at each radius correlates strongly with the average surface brightness at that radius, with Hubble type being an additional effect. Late type galaxies are bluer at the same surface brightness than early type galaxies.–The reddening profiles predicted by the dust models are incompatible with the data when all colours have to be fitted at the same time. Dust cannot be the major cause of the colour gradients.–The population synthesis models by Worthey (1994) indicate that the colour gradients cannot be caused by metallicity gradients alone.–The best fit to the data is reached in a model where the colour gradients are mainly caused by an age gradient across the disk, with an additional metallicity gradient to explain the very red central colours. The colours of galaxies of type later than Sc indicate that they have in general a lower metallicity at all radii than the earlier types.

scholarly journals Planetary Nebulae by the Strong [NII] Emission Lines

1993 ◽  
Vol 155 ◽  
pp. 195-195
Author(s):  
L. N. Kondratjeva
Keyword(s):  
Surface Brightness ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Low Surface Brightness

The sample of planetaries with the strong [NII] emission lines are analysed. All available parameters are discussed. The enrichments of all elements and the tendency to rather low surface brightness of ne bulae in Hβ flux are remarked. The deficiency of hydrogen in envelopes is proposed as the possible reason of observational spectra.

scholarly journals Dynamical Structures of Planetary Nebulae — Models Against Observations

1993 ◽  
Vol 155 ◽  
pp. 315-318 ◽  
Author(s):  
H. Marten ◽  
K. Gesicki ◽  
R. Szczerba
Keyword(s):  
Surface Brightness ◽  
Planetary Nebulae ◽  
Stellar Model ◽  
Emission Lines ◽  
Temperature Structure ◽  
Line Profiles ◽  
Ionized Gas ◽  
Model Calculations ◽  
Central Stars ◽  
Model Sequence

Hydrodynamical calculations of Planetary Nebulae (PNe) over 25000 yrs of evolution which include timedependent effects of ionization as well as variable central stars winds and parameters consistent with stellar model calculations show a great variety of velocity and density structures which strongly deviate from the often assumed “homogeneous shells, expanding with constant velocities” (Marten & Schönberner, 1991, hereafter MS). By means of a static photoionization code we calculate the surface brightness in the 10 most prominent nebular emission lines for density structures of the model sequence “VS” as given by MS. The obtained radial emissivities are used together with the velocity and temperature structure of the ionized gas to calculate (thermally broadened) line profiles in order to derive “measured” expansion velocities. We compare the theoretical surface brightnesses with observations and demonstrate some difficulties in the interpretation of nebular expansion velocities, expansion distances and ages.

The DIVING3D Project: Analysis of the nuclear region of Early-type Galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 454-456
Author(s):  
T. V. Ricci ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Emission Lines ◽  
H Ii Regions ◽  
Sample Type ◽  
Early Type ◽  
Integral Field Spectroscopy ◽  
Project Analysis ◽  
Line Region ◽  
Field Unit ◽  
Integral Field

AbstractIn this work, we present preliminary results regarding the nuclear emission lines of a statistically complete sample of 56 early-type galaxies that are part of the Deep Integral Field Spectroscopy View of Nuclei of Galaxies (DIVING3D) Project. All early type galaxies (ETGs) were observed with the Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) installed on the Gemini South Telescope. We detected emission lines in 93% of the sample, mostly low-ionization nuclear emission-line region galaxies (LINERs). We did not find Transition Objects nor H II regions in the sample. Type 1 objects are seen in ∼23% of the galaxies.

scholarly journals The relation between the gas, dust and total mass in edge-on spiral galaxies

2014 ◽  
Vol 10 (S309) ◽  
pp. 297-297
Author(s):  
Flor Allaert
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Spiral Galaxies ◽  
3D Structure ◽  
Early Type ◽  
Interstellar Gas ◽  
Data Set ◽  
Unique Role ◽  
Radio Data ◽  
Multi Wavelength

AbstractEach component of a galaxy plays its own unique role in regulating the galaxy's evolution. In order to understand how galaxies form and evolve, it is therefore crucial to study the distribution and properties of each of the various components, and the links between them, both radially and vertically. The latter is only possible in edge-on systems. We present the HEROES project, which aims to investigate the 3D structure of the interstellar gas, dust, stars and dark matter in a sample of 7 massive early-type spiral galaxies based on a multi-wavelength data set including optical, NIR, FIR and radio data.

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