Global properties of star formation in spiral galaxies

2008 ◽  
pp. 198-201
Author(s):  
T. N. Rengarajan ◽  
K. V. K. Iyengar
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Global Properties

scholarly journals BreakBRD Galaxies. I. Global Properties of Spiral Galaxies with Central Star Formation in Red Disks

2020 ◽  
Vol 889 (2) ◽  
pp. 188 ◽  
Author(s):  
Sarah E. Tuttle ◽  
Stephanie Tonnesen
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Central Star ◽  
Global Properties

Global properties of star formation in spiral galaxies

1988 ◽  
Vol 9 (2) ◽  
pp. 79-91
Author(s):  
T. N. Rengarajan ◽  
K. V. K. Iyengar
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Global Properties

scholarly journals Superassociations in the Arms of Normal and Active Galaxies

1987 ◽  
Vol 121 ◽  
pp. 545-565
Author(s):  
Jorge Melnick
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Hii Regions ◽  
Active Galaxies ◽  
Powerful Method ◽  
Late Type ◽  
Global Properties ◽  
Star Formation Regions ◽  
Extragalactic Distance Scale ◽  
Mass Functions

The properties of violent star formation regions in the arms of spiral galaxies are reviewed with the aim of providing the foundations on which models of nuclear starbursts can be built. It is argued that the classical examples of extranuclear starbursts, giant HII regions and Superassociations, are closely related but fundamentally different classes of objects; their properties are reviewed and discussed in detail.It is shown that giant HII regions are a homogeneous class of gravitationally bound objects ionized by starburst clusters and that the initial mass functions of these clusters change according to their chemical composition being flatter for metal poor systems. Superassociations are loose associations of associations which generally contain one or more giant HII regions. Star formation in superassociations is self-sustaining and therefore these structures may last much longer than individual giant HII regions.Isolated superassociations or HII galaxies are shown to have the same global properties as giant HII regions in late type galaxies. In particular, the correlations between Hβ luminosity and emission line velocity width are similar for both classes. Since HII galaxies can be observed out to large distances this correlation provides a potentially powerful method to calibrate the extragalactic distance scale. A preliminary calibration gives HO = 95 ± 9 km/sec/Mpc.The relations between the properties of giant HII regions and Superassociations with those of their parent galaxies are briefly discussed.

scholarly journals CHANG-ES

2018 ◽  
Vol 611 ◽  
pp. A72 ◽  
Author(s):  
Marita Krause ◽  
Judith Irwin ◽  
Theresa Wiegert ◽  
Arpad Miskolczi ◽  
Ancor Damas-Segovia ◽  
...  
Keyword(s):  
Star Formation ◽  
Wind Velocity ◽  
Surface Density ◽  
Spiral Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Cosmic Ray ◽  
Scale Height ◽  
Radio Continuum ◽  
Frequency Bands

Aim. The vertical halo scale height is a crucial parameter to understand the transport of cosmic-ray electrons (CRE) and their energy loss mechanisms in spiral galaxies. Until now, the radio scale height could only be determined for a few edge-on galaxies because of missing sensitivity at high resolution.Methods. We developed a sophisticated method for the scale height determination of edge-on galaxies. With this we determined the scale heights and radial scale lengths for a sample of 13 galaxies from the CHANG-ES radio continuum survey in two frequency bands.Results. The sample average values for the radio scale heights of the halo are 1.1 ± 0.3 kpc in C-band and 1.4 ± 0.7 kpc in L-band. From the frequency dependence analysis of the halo scale heights we found that the wind velocities (estimated using the adiabatic loss time) are above the escape velocity. We found that the halo scale heights increase linearly with the radio diameters. In order to exclude the diameter dependence, we defined a normalized scale height h˜ which is quite similar for all sample galaxies at both frequency bands and does not depend on the star formation rate or the magnetic field strength. However, h˜ shows a tight anticorrelation with the mass surface density.Conclusions. The sample galaxies with smaller scale lengths are more spherical in the radio emission, while those with larger scale lengths are flatter. The radio scale height depends mainly on the radio diameter of the galaxy. The sample galaxies are consistent with an escape-dominated radio halo with convective cosmic ray propagation, indicating that galactic winds are a widespread phenomenon in spiral galaxies. While a higher star formation rate or star formation surface density does not lead to a higher wind velocity, we found for the first time observational evidence of a gravitational deceleration of CRE outflow, e.g. a lowering of the wind velocity from the galactic disk.

scholarly journals Clumpy Galaxies in the Early Universe

2006 ◽  
Vol 2 (S235) ◽  
pp. 376-380 ◽  
Author(s):  
Debra Meloy Elmegreen
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
Spiral Galaxies ◽  
Star Forming ◽  
Wide Range ◽  
Thick Disks ◽  
Hubble Ultra Deep Field

AbstractClumpy galaxies are prominent in the early Universe. We present morphological and photometric properties of a wide range of galaxy types and their star-forming clumps in the Hubble Ultra Deep Field. Sizes, scale lengths, and scale heights suggest that galaxies grow by a factor of 2 fromz= 4 to the present, and that thick disks are present in the early Universe. The largest clumps of star formation are 107–109M⊙in different galaxies, much more massive than large star-forming complexes in local galaxies. Dissolved clumps may account for both the exponential disks and the early thick disks of spirals and proto-spiral galaxies.

scholarly journals Bar rejuvenation in S0 galaxies?

2020 ◽  
Vol 495 (4) ◽  
pp. 4548-4556
Author(s):  
Sudhanshu Barway ◽  
Kanak Saha
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Theoretical Studies ◽  
Tidal Interactions ◽  
Colour Measurements ◽  
Induce Star Formation ◽  
Minor Mergers ◽  
Stellar Masses ◽  
S0 Galaxies ◽  
Intermediate Density

ABSTRACT Based on the colour measurements from a multiband, multicomponent 2D decompositions of S0 and spiral galaxies using SDSS images, we found that bars are bluer in S0 galaxies compared to the spiral galaxies. Most of the S0s in our sample have stellar masses ∼L* galaxies. The environment might have played an important role as most of the S0s with bluer bars are in the intermediate-density environment. The possibility of minor mergers and tidal interactions that occurs frequently in the intermediate-density environment might have caused either a bar to form and/or induce star formation in the barred region of S0 galaxies. The underlying discs show the usual behaviour being redder in S0s compared to spiral galaxies while the bulges are red and old for both S0 and spiral galaxies. The finding of bluer bars in S0 galaxies is a puzzling issue and poses an interesting question at numerical and theoretical studies most of which shows that the bars are long-lived structures with old stellar populations.

scholarly journals Star formation bursts in isolated spiral galaxies

2006 ◽  
Vol 371 (2) ◽  
pp. 530-536 ◽  
Author(s):  
C. Clarke ◽  
D. Gittins
Keyword(s):  
Star Formation ◽  
Spiral Galaxies

scholarly journals Star Formation in Normal Irregular Galaxies

1987 ◽  
Vol 115 ◽  
pp. 611-612
Author(s):  
Deidre A. Hunter
Keyword(s):  
Star Formation ◽  
Large Range ◽  
Density Waves ◽  
Regulatory Processes ◽  
Spiral Density Waves ◽  
Global Properties ◽  
Level Of Activity ◽  
Star Formation Activity ◽  
Irregular Galaxies

Normal, non-interacting irregular galaxies can be quite successful at forming stars. Therefore, spiral density waves are not necessary to a vigorous production of stars. Nevertheless, there is a large range in star-formation rates among irregular galaxies. Irregulars with common characteristics can have different overall levels of star-formation activity, so that the level of activity does not seem to be simple related to observable global properties of galaxian systems. The constant star formation rates of most normal irregulars also imply the existence of regulatory processes.

scholarly journals Environmental Effects on the ISM and Star Formation Properties of Nearby Spiral Galaxies

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Angus Mok ◽  
Christine Wilson
Keyword(s):  
Star Formation ◽  
Environmental Effects ◽  
Spiral Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Molecular Gas ◽  
Turbulent Pressure ◽  
Cluster Environment ◽  
Gas Properties

AbstractWe studied molecular gas properties in a sample of 98 Hi - flux selected spiral galaxies within ~ 25 Mpc using the CO J = 3 − 2 line, observed with the JCMT, and subdivided into isolated, group, and Virgo subsamples. We find a larger mean H2 mass in the Virgo galaxies compared to group galaxies, despite their lower mean Hi mass. Combining our data with complementary Hα star formation rate measurements, Virgo galaxies have a longer molecular gas depletion times compared to group galaxies, perhaps due to heating processes in the cluster environment or differences in the turbulent pressure.

scholarly journals Relation Between Star Formation and Angular Momentum in Spiral Galaxies

1983 ◽  
Vol 100 ◽  
pp. 135-136
Author(s):  
L. Carrasco ◽  
A. Serrano
Keyword(s):  
Angular Momentum ◽  
Star Formation ◽  
Radial Distribution ◽  
Spiral Galaxies ◽  
Formation Rate ◽  
Inverse Function ◽  
Solar Neighborhood ◽  
Spin Angular Momentum ◽  
Stellar Formation ◽  
The Galaxy

We derive the radial distribution of the specific angular momentum j=J/M, for the gas in M31, M51 and the galaxy, objects for which well observed unsmoothed rotation curves are available in the literature. We find the specific angular momentum to be anti-correlated with the present stellar formation rate, i.e. minima of spin angular momentum correspond to the loci of spiral arms. We find that the stellar formation rate is an inverse function of j. We derive new values of Oort's A constant for the arm and interarm regions in the solar neighborhood.

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