scholarly journals Distances, depth structure, and kinematics of the Magellanic Clouds from disentangling spectra of eclipsing binaries and Cepheids

2012 ◽  
Vol 8 (S289) ◽  
pp. 231-234
Author(s):  
P. Hadrava ◽  
S. Štefl ◽  
R. Klement ◽  
C. Martayan
Keyword(s):  
Radial Velocity ◽  
Local Group ◽  
Velocity Structure ◽  
Magellanic Clouds ◽  
Eclipsing Binaries ◽  
Physical Parameters ◽  
Kinematic Structure ◽  
Upper Limit ◽  
The Galaxy ◽  
Method Yield

AbstractSpectroscopy and photometry of eclipsing binaries and Cepheids (using the Baade–Wesselink method) yield primary distance markers applicable to the Local Group of galaxies. The technique of disentangling spectra has proved helpful in resolving stellar physical parameters. Our method also allows us to disentangle interstellar absorption lines and, thus, to complement the radial-velocity structure of the interstellar medium with an (otherwise unattainable) upper limit to its distance. The mapping of the spatial and kinematic structure of the stellar and interstellar components of the Magellanic Clouds and Stream enables constraining their tidal evolution and, thus, of the mass of the Galaxy.

Coravel Radial-Velocity Curves for Cepheids in the Large Magellanic Cloud

1984 ◽  
Vol 88 ◽  
pp. 375-380
Author(s):  
M. Imbert ◽  
J. Andersen ◽  
A. Ardeberg ◽  
C. Bardin ◽  
W. Benz ◽  
...  
Keyword(s):  
Comparative Study ◽  
Radial Velocity ◽  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Magellanic Clouds ◽  
Independent Determination ◽  
Fundamental Information ◽  
The Galaxy ◽  
Cepheid Variables

Radii and luminosities for Cepheid variables provide fundamental information on stellar evolution. Such data, obtained by the Baade-Wesselink method, are available and have been used for a number of galactic Cepheids. It is of particular interest to obtain corresponding data for Cepheids in the Magellanic Clouds. Firstly, this allows a comparative study of stellar evolution between the Galaxy and the Magellanic Clouds. Secondly, it provides data for an independent determination of the distance to the Magellanic Clouds.Radial-velocity observations have been made for a total of around 20 Cepheid variables in both the LMC and the SMC. All measurements were made with the photoelectric scanner CORAVEL attached to the Cassegrain focus of the Danish 1.54-m telescope at European Southern Observatory, La Silla, Chile. Observations were made from January 1981 through October 1983. The accuracy of individual radial-velocity observations is of the order of 1 km s−1. The B magnitudes of the six Cepheids presented range from 13.0 to 15.5.

scholarly journals Towards a fully automated eclipsing binary solver for Gaia

2008 ◽  
Vol 4 (S253) ◽  
pp. 402-403
Author(s):  
Brandon Tingley ◽  
Gilles Sadowski ◽  
Christos Siopis
Keyword(s):  
Radial Velocity ◽  
High Precision ◽  
Eclipsing Binaries ◽  
Physical Parameters ◽  
Graphical Interface ◽  
Velocity Measurements ◽  
New Approach ◽  
Eclipsing Binary ◽  
Photometric Observations

AbstractGaia, an ESA cornerstone mission, will obtain of the order of 100 high-precision photometric observations and lower precision radial velocity measurements over five years for around a billion stars – several hundred thousand of which will be eclipsing binaries. In order to extract the characteristics of these systems, a fully automated code must be available. During the process of this development, two tools that may be of use to the transit community have emerged: a very fast, simple, detached eclipsing binary simulator/solver based on a new approach and an interacting eclipsing binary simulator with most of the features of the Wilson-Devinney and Nightfall codes, but fully documented and written in easy-to-follow and highly portable Java. Currently undergoing development and testing, this code includes an intuitive graphical interface and an optimizer for the estimation of the physical parameters of the system.

scholarly journals Planetary nebulae as tracers of the kinematic structure of the starburst galaxy IC 10

2011 ◽  
Vol 7 (S283) ◽  
pp. 368-369
Author(s):  
Denise R. Gonçalves ◽  
Ana M. Teodorescu ◽  
Alan Alves-Brito ◽  
Roberto H. Méndez ◽  
Laura Magrini
Keyword(s):  
Star Formation ◽  
Kinematic Analysis ◽  
Local Group ◽  
Stellar Populations ◽  
Starburst Galaxy ◽  
Kinematic Structure ◽  
Irregular Galaxy ◽  
Tidal Interactions ◽  
Ic 10 ◽  
The Galaxy

AbstractThe Local Group dwarf irregular galaxy IC 10 is the nearest starburst galaxy (at 725 kpc) and presents extended and complex HI kinematics. It is believed that IC 10 is still experiencing an intense and very recent burst of star formation, likely triggered by infalling gas from an extended envelope which is counter-rotating with respect to the galaxy proper rotation. In this contribution we summarize our preliminary results (Gonçalves et al. 2011, in prep.) obtained by performing a kinematic analysis of the PN population of IC 10. Our aim is to explore the kinematic connection of its intermediate to old stellar populations with that obtained from HI observations. Some PNe were found at large galactocentric distances and could therefore represent a trace of past tidal interactions.

scholarly journals B-supergiants in IC1613: testing low-Z massive star physics and evolution

2016 ◽  
Vol 12 (S329) ◽  
pp. 389-389
Author(s):  
Inés Camacho ◽  
Miriam García ◽  
Miguel A. Urbaneja ◽  
Artemio Herrero
Keyword(s):  
Massive Star ◽  
Local Group ◽  
Uv Spectroscopy ◽  
Physical Parameters ◽  
Physical Processes ◽  
Life And Death ◽  
The Galaxy ◽  
Nearby Galaxies ◽  
Group Galaxy ◽  
Local Group Galaxy

AbstractThe physical processes taking place in massive stars during their life and death are highly dependent on the metallicity (Z) of their parent cloud. Observations of these stars in low-Z nearby galaxies are crucial to understand these processes. IC1613 is the nearest Local Group galaxy with ongoing star formation and O-abundance lower than the SMC, although UV spectroscopy suggests it is not so metal poor. We performed a spectral analysis of early B-type stars in the galaxy, obtaining physical parameters and abundances. Our results confirm the low O-abundance of IC1613.

scholarly journals Abundances in Local Group Planetary Nebulae

1995 ◽  
Vol 10 ◽  
pp. 480-482
Author(s):  
James B. Kaler
Keyword(s):  
Local Group ◽  
Initial Conditions ◽  
Planetary Nebulae ◽  
Magellanic Clouds ◽  
Chemical Compositions ◽  
Core Mass ◽  
Know How ◽  
Chemical Enrichment ◽  
Clear Link ◽  
The Galaxy

We are able to measure the chemical compositions of hundreds of planetary nebulae in our own Galaxy and in the Magellanic Clouds. Why, therefore, do we need to expend the effort to observe much more difficult targets in other Local Group galaxies? A severe lack of distances does not allow us to place Galactic planetary nuclei on the log L-log T plane with any degree of accuracy, so we cannot properly examine composition differences relative to core mass and state of evolution. We can perform such tasks for Magellanic Cloud objects, but do not know how the Clouds’ low-metallicities affect the results, and thus do not know how this sample of planetaries relates to the nebulae in our own system. We know, for example, that in the Clouds, nitrogen enrichment begins above a core mass of about 0.68 M⊙ (Kaler and Jacoby 1990), but other than a clear link between core mass and chemical enrichment in the Galaxy, do not know at what point it becomes important. To study such relationships, we therefore have to go to other galaxies with a variety of initial conditions for which distances are secure, namely those of the Local Group.

scholarly journals Seeing Double in the Local Group: Extragalactic Binaries

2005 ◽  
Vol 13 ◽  
pp. 446-446
Author(s):  
Edward F. Guinan
Keyword(s):  
Binary Systems ◽  
Local Group ◽  
Magellanic Clouds ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Major Advance ◽  
Future Expectations ◽  
High Quantum ◽  
Orbital Periods

Photographic surveys of the Magellanic Clouds and the M31 carried decades ago discovered ~200 close binaries. In most cases the photographic light curves are good enough only to identify the stars as close (mostly eclipsing) binaries and to estimate orbital periods and binary type. Except for a few cases, little useful information may be obtained from these stars except to be reassured that eclipsing binary (EB) systems are present in other galaxies. However a major advance occurred with the advent of high quantum efficient CCDs. Because of this an explosion in the number of known extragalactic binaries occurred during the 1990s as offshoots of photometric microlensing surveys such as EROS, MACHO, and OGLE. Now over 10 000 extragalactic EBs have been identified. Also, photometric surveys of M31 and M33 (e.g. DIRECT) are discovering many more 19-20th mag eclipsing/close binaries. Over the next decade it is expected that ~1 million new binary systems will be identified in these galaxies. In this overview I will discuss recent advances and future expectations in the studies of extragalactic binaries

scholarly journals The star formation histories of the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 138-138
Author(s):  
H. R. Butcher
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Local Group ◽  
High Redshift ◽  
Magellanic Clouds ◽  
Empirical Methods ◽  
Star Forming ◽  
Two Systems ◽  
The Galaxy ◽  
Star Formation Histories

Existing observations of the Magellanic Clouds suggest substantially different star-forming histories for the two systems. The reliability of this conclusion is discussed in the context of the uncertainties and age resolutions of various empirical methods of studying galaxy evolution. An attempt is also made to relate likely evolutionary scenarios for the Clouds to the histories of other Local Group systems, to the evolution seen in galaxies at high redshift, and to possible histories determined by interaction with the Galaxy.

scholarly journals Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes

2019 ◽  
Vol 491 (4) ◽  
pp. 5489-5497 ◽  
Author(s):  
Oleg Yu Malkov
Keyword(s):  
Radial Velocity ◽  
Velocity Curve ◽  
Eclipsing Binaries ◽  
Physical Parameters ◽  
Radial Velocity Curve ◽  
Orbital Parameters ◽  
Comprehensive List ◽  
Use Of Data ◽  
Rare Classes

ABSTRACT Semidetached eclipsing systems provide a unique opportunity to derive the basic properties of interacting binaries. The goal of this work is to collect and to make use of data on semidetached systems with available light and radial velocity curve solutions. I have compiled the most comprehensive list to date, of 119 semidetached double-lined eclipsing binaries, containing the orbital parameters and physical parameters of the components. I consider the classification of semidetached binaries and discuss gaps between various classes in the Hertzspung–Russell diagram. I list systems with component parameters that are inverted and briefly discuss their evolutionary state.

scholarly journals The Magellanic Stream: Observational Considerations

1979 ◽  
Vol 84 ◽  
pp. 547-556 ◽  
Author(s):  
D. S. Mathewson ◽  
V. L. Ford ◽  
M. P. Schwarz ◽  
J. D. Murray
Keyword(s):  
Local Group ◽  
Galactic Center ◽  
Neutral Hydrogen ◽  
Great Circle ◽  
Magellanic Clouds ◽  
Systematic Variation ◽  
The Sun ◽  
The South ◽  
The Galaxy ◽  
Magellanic Stream

The Magellanic Stream is an arc of neutral hydrogen which nearly follows a great circle and which contains the Magellanic Clouds - hence its name (Mathewson, Cleary and Murray 1974). This great circle passes within a few degrees of the south galactic pole and lies close to the supergalactic plane. Mathewson and Schwarz (1976) argued that this indicates that the Magellanic Stream and Magellanic Clouds are not bound to the Galaxy. To reinforce this argument, they pointed out that around the supergalactic plane there is a similar systematic variation in the velocities of the Local Group and those of the Stream which may be due to the reflection of the motion of the galactic center if the velocity of rotatior of the Sun is 225 km s−1; if it is 290 km s−1 then the grounds for this argument would disappear.

scholarly journals The Magellanic Stream: theoretical considerations

1979 ◽  
Vol 84 ◽  
pp. 557-566 ◽  
Author(s):  
M. Fujimoto
Keyword(s):  
Local Group ◽  
Galactic Disk ◽  
Magellanic Clouds ◽  
Particle Simulation ◽  
The Past ◽  
Local Supercluster ◽  
New Models ◽  
The Galaxy ◽  
Magellanic Stream ◽  
Theoretical Considerations

The tidal and the primordial theories for the Magellanic Stream are examined in a frame of test-particle simulation for the interacting triple system of the Galaxy, the Large and Small Magellanic Clouds (LMC and SMC). Difficulties of the radial velocity of the Stream still beset these two theories. Several new models for the Stream and the Clouds are briefly discussed in relation to the bending of the galactic disk, the past binary orbits of the LMC and SMC and also the Local Group and the Local Supercluster of galaxies.

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