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Open AccessJournal ArticleDOI

Nobeyama CO Atlas of Nearby Spiral Galaxies: Distribution of Molecular Gas in Barred and Nonbarred Spiral Galaxies

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TLDR
In this paper, the influence of bar on the distribution of molecular gas in spiral galaxies using the data from a CO(1 - 0) mapping survey of 40 nearby spiral galaxies performed with the Nobeyama 45m telescope is presented.
Abstract
The data from a CO(1 - 0) mapping survey of 40 nearby spiral galaxies performed with the Nobeyama 45-m telescope are presented. The criteria of the sample selection were (1) RC3 morphological type in the range Sa to Scd, (2) distance less than 25 Mpc, (3) inclination angle less than 79deg (RC3), (4) flux at 100 um higher than ~ 10 Jy, (5) spiral structure is not destroyed by interaction. The maps of CO cover most of the optical disk of the galaxies. We investigated the influence of bar on the distribution of molecular gas in spiral galaxies using these data. We confirmed that the degree of central concentration is higher in barred spirals than in non-barred spirals as shown by the previous works. Furthermore, we present an observational evidence that bars are efficient in driving molecular gas that lies within the bar length toward the center, while the role in bringing gas in from the outer parts of the disks is small. The transported gas accounts for about half of molecular gas within the central region in barred spiral galaxies. We found a correlation between the degree of central concentration and bar strength. Galaxies with stronger bars tend to have higher central concentration. The correlation implies that stronger bars accumulate molecular gas toward the center more efficiently. These results are consistent with long-lived bars.

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2MASS large galaxy atlas

Abstract: We present the largest galaxies as seen in the near-infrared (1–2 μm), imaged with the Two Micron All Sky Survey (2MASS), ranging in angular size from 1' to 15. We highlight the 100 largest in the sample. The galaxies span all Hubble morphological types, including elliptical galaxies, normal and barred spirals, and dwarf and peculiar classes. The 2MASS Large Galaxy Atlas provides the necessary sensitivity and angular resolution to examine in detail morphologies in the near-infrared, which may be radically different from those in the optical. Internal structures such as spirals, bulges, warps, rings, bars, and star formation regions are resolved by 2MASS. In addition to large mosaic images, the atlas includes astrometric, photometric, and shape global measurements for each galaxy. A comparison of fundamental measures (e.g., surface brightness, Hubble type) is carried out for the sample and compared with the Third Reference Catalogue. We further showcase NGC 253 and M51 (NGC 5194/5195) to demonstrate the quality and depth of the data. The atlas represents the first uniform, all-sky, dust-penetrated view of galaxies of every type, as seen in the near-infrared wavelength window that is most sensitive to the dominant mass component of galaxies. The images and catalogs are available through the NASA/IPAC Extragalactic Database and Infrared Science Archive and are part of the 2MASS Extended Source Catalog.
References
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Book ChapterDOI

Third Reference Catalogue of Bright Galaxies

TL;DR: In this article, a reference catalogue of bright galaxies in three volumes reflects the explosive growth of extragalactic astronomy over the last 15 years and includes all galaxies with apparent diameters larger than one arc minute, magnitudes brighter than about magnitude 15.5, and redshifts not larger than 15,000 km/sec.
Journal ArticleDOI

The FIRST Survey: Faint Images of the Radio Sky at twenty centimeters

TL;DR: The first year of the First Radio Sky at Twenty centimeters (FIRST) survey as discussed by the authors was performed using the NRAO Very Large Array (VLA) with a total of 144 hr of time in 1993 April and May was used for a variety of tests, as well as to cover an initial strip of the survey extending between 07{sup h}15{sup m} and 16{suph}30{supm} in a 2{sq_bullet}8 wide declination zone passing through the local zenith.
Journal ArticleDOI

Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

TL;DR: In the far future, evolution will mostly be secular, the slow rearrangement of energy and mass that results from interactions involving collective phenomena such as bars, oval disks, spiral structure, and triaxial dark halos as mentioned in this paper.
Journal ArticleDOI

The 2MASS Large Galaxy Atlas

TL;DR: The 2MASS Large Galaxy Atlas as mentioned in this paper provides the necessary sensitivity and angular resolution to examine in detail morphologies in the near-infrared, which may be radically different from those in the optical.
Journal ArticleDOI

The existence and shapes of dust lanes in galactic bars

TL;DR: In this article, the flow of gas in and around the bars or ovals of model barred galaxies is studied, and it is intimately linked to the properties of the periodic orbits.
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