Near-Infrared Observations of Isophotal Twists in Barred Spiral Galaxies

1996 ◽  
Vol 111 ◽  
pp. 1880 ◽  
Author(s):  
Debra Meloy Elmegreen ◽  
Bruce G. Elmegreen ◽  
Frederick R. Chromey ◽  
David Alan Hasselbacher ◽  
Bradley A. Bissell
Keyword(s):  
Near Infrared ◽  
Spiral Galaxies ◽  
Infrared Observations ◽  
Barred Spiral Galaxies

scholarly journals Circumnuclear regions in barred spiral galaxies — I. Near-infrared imaging

2000 ◽  
Vol 317 (2) ◽  
pp. 234-248 ◽  
Author(s):  
D. Pérez-Ramírez ◽  
J. H. Knapen ◽  
R. F. Peletier ◽  
S. Laine ◽  
R. Doyon ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Spiral Galaxies ◽  
Near Infrared Imaging ◽  
Barred Spiral Galaxies

STRUCTURES OUT OF CHAOS IN BARRED-SPIRAL GALAXIES

2012 ◽  
Vol 22 (09) ◽  
pp. 1230029 ◽  
Author(s):  
P. A. PATSIS
Keyword(s):  
Near Infrared ◽  
Spiral Galaxies ◽  
Morphological Features ◽  
Infrared Images ◽  
Chaotic Motions ◽  
Spiral Arms ◽  
Gravitational Fields ◽  
Pattern Speed ◽  
Barred Spiral Galaxies ◽  
Kinematical Data

We review the dynamical mechanisms we have found to support the morphological features in barred-spiral galaxies based on chaotic motions of stars in their gravitational fields. These morphological features are the spiral arms, that emerge out of the ends of the bar, but also shape the bar itself. The potentials used have been estimated directly from near-infrared images of barred-spiral galaxies. In this paper, we present the results from the study of the dynamics of the potentials of the galaxies NGC 4314, NGC 1300 and NGC 3359. The main unknown parameter in our models is the pattern speed of the system Ωp. By varying Ωp, we have investigated several cases trying to match the results of our modeling with available photometrical and kinematical data. We found realistic models with stars on spirals in chaotic motion, while their bars are built by stars usually on regular orbits. However, we also encountered cases, where a major part of trajectories of the stars even in the bar is chaotic as well. Finally, we examined the gas dynamics of barred-spiral systems, and found that the presence of gas reinforces the intensity of the "chaotic" spiral arms.

scholarly journals Bar Properties as a Function of Hubble Type

1996 ◽  
Vol 157 ◽  
pp. 23-29
Author(s):  
Debra Meloy Elmegreen
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Spiral Galaxies ◽  
Infrared Light ◽  
Surface Photometry ◽  
Optical Surface ◽  
Barred Galaxies ◽  
Additional Information ◽  
Grand Design ◽  
Barred Spiral Galaxies

AbstractPrevious optical surface photometry of barred spiral galaxies revealed that there are two distinct types of bars: large bars tend to have a nearly constant surface brightness (”flat“ bar), while smaller bars tend to have a decreasing surface brightness with a scale length similar to the disk (”exponential“ bar). Statistically, flat bars tend to occur in early Hubble types and exponential bars in later types. Studies of resonances in spirals indicate that flat bars end inside corotation, while exponential bars end between the inner Lindblad and 4:1 resonances. Near-infrared (JHK) surface photometry of bars is presented in order to compare the stellar distributions and bar potentials in flat and exponential barred galaxies. The presence of isophotal twists in some galaxies provides additional information on resonances. The grand design and fiocculent optical structures in the two types of barred galaxies will be compared and contrasted with their near-infrared light distributions.

scholarly journals The Florida Barred Galaxy Program

1996 ◽  
Vol 157 ◽  
pp. 398-404 ◽  
Author(s):  
J. H. Hunter ◽  
S. T. Gottesman
Keyword(s):  
Near Infrared ◽  
University Of Florida ◽  
Infrared Observations ◽  
Density Distributions ◽  
Group Members ◽  
Grid Codes ◽  
Barred Spiral Galaxies ◽  
Pattern Speeds ◽  
Tree Codes ◽  
The University

AbstractFor more than a decade, a group at the University of Florida has been constructing models of barred spiral galaxies that we have observed at the VLA. Group members include: S. T. Gottesman, G. Contopoulos, J. H. Hunter, several Ph.D. students, and collaborators at other institutions. The HI distributions in our galaxies are either gas rich, or nearly devoid of gas, in their bar regions. Initially, we deduced density distributions and potentials of the stellar disks and bars from near infrared observations, modeled the gas response assuming different pattern speeds, etc., and compared the models with our HI observations. This simple approach is successful in some cases, such as NGC 3359, but less successful in others. More recently, our approach has been toward selfconsistent models, including stars and gas. Our techniques range from the Contopoulos-Grosbøl-Kaufmann stellar dynamical approach to methods exploiting grid codes and SPH tree codes. Some of our observations and models will be reviewed, and some new results will be presented.

scholarly journals The Frequency of Barred Spiral Galaxies in the Near-Infrared

2000 ◽  
Vol 119 (2) ◽  
pp. 536-544 ◽  
Author(s):  
Paul B. Eskridge ◽  
Jay A. Frogel ◽  
Richard W. Pogge ◽  
Alice C. Quillen ◽  
Roger L. Davies ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spiral Galaxies ◽  
Barred Spiral Galaxies

scholarly journals Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

1997 ◽  
Vol 163 ◽  
pp. 725-726
Author(s):  
K.-W. Hodapp ◽  
E. F. Ladd
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Point Sources ◽  
Spectral Energy ◽  
Infrared Observations ◽  
Circumstellar Material ◽  
Dense Cores ◽  
Wavelength Radiation ◽  
Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

scholarly journals Comparison of satellite microwave backscattering (ASCAT) and visible/near-infrared reflectances (PARASOL) for the estimation of aeolian aerodynamic roughness length in arid and semi-arid regions

2012 ◽  
Vol 5 (2) ◽  
pp. 2933-2957
Author(s):  
C. Prigent ◽  
C. Jiménez ◽  
J. Catherinot
Keyword(s):  
Arid Regions ◽  
Near Infrared ◽  
Roughness Length ◽  
Aerodynamic Roughness Length ◽  
Sources Of Information ◽  
Transport Models ◽  
Dust Transport ◽  
Infrared Observations ◽  
Aerodynamic Roughness ◽  
Semi Arid

Abstract. Previous studies examined the possibility to estimate the aeolian aerodynamic roughness length from satellites, either from visible/near-infrared observations or from microwave backscattering measurements. Here we compare the potential of the two approaches and propose to merge the two sources of information to benefit from their complementary aspects, i.e. the high spatial resolution of the visible/near-infrared (PARASOL part of the A-Train) and the independence from atmospheric contamination of the active microwaves (ASCAT on board MetOp). A global map of the aeolian aerodynamic roughness length at 6 km resolution is derived, for arid and semi-arid regions. It shows very good consistency with the existing information on the properties of these surfaces. The dataset is available to the community, for use in atmospheric dust transport models.

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