scholarly journals Dense Molecular Gas Associated with the Circumnuclear Star‐forming Ring in the Barred Spiral Galaxy NGC 6951

1999 ◽  
Vol 511 (1) ◽  
pp. 157-177 ◽  
Author(s):  
Kotaro Kohno ◽  
Ryohei Kawabe ◽  
Baltasar Vila‐Vilaro
Keyword(s):  
Spiral Galaxy ◽  
Molecular Gas ◽  
Star Forming ◽  
Barred Spiral Galaxy

scholarly journals 3.26. Molecular gas in the nuclear region and the bar of NGC 253

1998 ◽  
Vol 184 ◽  
pp. 141-142
Author(s):  
K. Sorai ◽  
N. Nakai ◽  
N. Kuno ◽  
K. Nishiyama
Keyword(s):  
Radio Telescope ◽  
Inclination Angle ◽  
Spiral Galaxy ◽  
Early Stage ◽  
Emission Lines ◽  
Molecular Gas ◽  
Nuclear Region ◽  
Star Forming ◽  
Barred Spiral Galaxy

In order to study relationship between molecular gas and star-forming activities, we have made observations of the barred spiral galaxy NGC 253 in 12CO(J = 1–0), 13CO(J = 1–0), and HCN(J = 1–0) emission lines with the Nobeyama 45-m radio telescope. NGC 253 is located in a distance of 2.5 M pc(Mauersbergeretal.(1996)) and has an inclination angle of 78°.5 (Pence 1980). This galaxy has a starburst nuclear region and is suggested in an early stage of a starburst (Rieke, Lebofsky, & Walker (1988)).

scholarly journals The Nuclear Ring in the Barred Spiral Galaxy IC 4933

2010 ◽  
Vol 27 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Stuart D. Ryder ◽  
Samuel M. Illingworth ◽  
Robert G. Sharp ◽  
Catherine L. Farage
Keyword(s):  
Spiral Galaxy ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Star Formation History ◽  
Star Forming ◽  
Star Forming Regions ◽  
The North ◽  
Contact Points ◽  
Nuclear Ring ◽  
Barred Spiral Galaxy

AbstractWe present infrared imaging from IRIS2 on the Anglo–Australian Telescope that shows the barred spiral galaxy IC 4933 has not just an inner ring encircling the bar, but also a star-forming nuclear ring 1.5 kpc in diameter. Imaging in the u′ band with GMOS on Gemini South confirms that this ring is not purely an artifact due to dust. Optical and near-infrared colours alone however cannot break the degeneracy between age, extinction, and burst duration that would allow the star formation history of the ring to be unraveled. Integral field spectroscopy with the GNIRS spectrograph on Gemini South shows the equivalent width of the Paβ line to peak in the north and south quadrants of the ring, indicative of a bipolar azimuthal age gradient around the ring. The youngest star-forming regions do not appear to correspond to where we expect to find the contact points between the offset dust lanes and the nuclear ring unless the nuclear ring is oval in shape, causing the contact points to lead the bar by more than 90°.

Dust and Molecular Gas in the Barred Spiral Galaxy NGC 1530

1995 ◽  
Vol 449 ◽  
pp. 576 ◽  
Author(s):  
Michael W. Regan ◽  
Stuart N. Vogel ◽  
Peter J. Teuben
Keyword(s):  
Spiral Galaxy ◽  
Molecular Gas ◽  
Barred Spiral Galaxy

scholarly journals Zoom-in cosmological hydrodynamical simulation of a star-forming barred, spiral galaxy at redshift z = 2

2019 ◽  
Vol 488 (4) ◽  
pp. 4674-4689 ◽  
Author(s):  
Fiorenzo Vincenzo ◽  
Chiaki Kobayashi ◽  
Tiantian Yuan
Keyword(s):  
Star Formation ◽  
Angular Velocity ◽  
Spiral Galaxy ◽  
Stellar Populations ◽  
Spiral Arms ◽  
Star Forming ◽  
Thin Disc ◽  
The Galaxy ◽  
Barred Spiral Galaxy ◽  
Zoom In

ABSTRACTWe present gas and stellar kinematics of a high-resolution zoom-in cosmological chemodynamical simulation, which fortuitously captures the formation and evolution of a star-forming barred spiral galaxy, from redshift z ∼ 3 to z ∼ 2 at the peak of the cosmic star formation rate. The galaxy disc grows by accreting gas and substructures from the environment. The spiral pattern becomes fully organized when the gas settles from a thick (with vertical dispersion σv > 50 km s−1) to a thin (σv ∼ 25 km s−1) disc component in less than 1 Gyr. Our simulated disc galaxy also has a central X-shaped bar, the seed of which formed by the assembly of dense gas-rich clumps by z ∼ 3. The star formation activity in the galaxy mainly happens in the bulge and in several clumps along the spiral arms at all redshifts, with the clumps increasing in number and size as the simulation approaches z = 2. We find that stellar populations with decreasing age are concentrated towards lower galactic latitudes, being more supported by rotation, and having also lower velocity dispersion; furthermore, the stellar populations on the thin disc are the youngest and have the highest average metallicities. The pattern of the spiral arms rotates like a solid body with a constant angular velocity as a function of radius, which is much lower than the angular velocity of the stars and gas on the thin disc; moreover, the angular velocity of the spiral arms steadily increases as a function of time, always keeping its radial profile constant. The origin of our spiral arms is also discussed.

scholarly journals CO Multi-line Imaging of Nearby Galaxies (COMING). I. Physical properties of molecular gas in the barred spiral galaxy NGC 2903

2016 ◽  
Vol 68 (5) ◽  
pp. 89 ◽  
Author(s):  
Kazuyuki Muraoka ◽  
Kazuo Sorai ◽  
Nario Kuno ◽  
Naomasa Nakai ◽  
Hiroyuki Nakanishi ◽  
...  
Keyword(s):  
Physical Properties ◽  
Spiral Galaxy ◽  
Molecular Gas ◽  
Nearby Galaxies ◽  
Barred Spiral Galaxy ◽  
Line Imaging

scholarly journals ASTE CO(3-2) observations of M 83: Correlation between CO(3-2)/CO(1-0) ratios and star formation efficiencies

2006 ◽  
Vol 2 (S237) ◽  
pp. 451-451
Author(s):  
K. Muraoka ◽  
K. Kohno ◽  
T. Tosaki ◽  
N. Kuno ◽  
K. Nakanishi ◽  
...  
Keyword(s):  
Star Formation ◽  
Spatial Variation ◽  
Radial Profile ◽  
Radio Continuum ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Integrated Intensity ◽  
Barred Spiral Galaxy ◽  
Simple Summation

AbstractWe have performed CO(J=3−2) emission observations with the Atacama Submillimeter Telescope Experiment (ASTE) toward the 5′ × 5′ (or 6.6 × 6.6 kpc at the distance D = 4.5 Mpc) region of the nearby barred spiral galaxy M 83. We successfully resolved the major structures, i.e., the nuclear starburst region, bar, and inner spiral arms in CO(J=3−2) emission at a resolution of 22'' (or 480 pc), showing a good spatial coincidence between CO(J=3−2) and 6 cm continuum emissions.From a comparison of CO(J=3−2) data with CO(J=1−0) intensities measured with Nobeyama 45-m telescope, we found that the radial profile of CO(J=3−2)/CO(J=1−0) integrated intensity ratio R3−2/1−0 is almost unity in the central region (r<0.25 kpc), whereas it drops to a constant value, 0.6–0.7, in the disk region. The radial profile of star formation efficiencies (SFEs), determined from 6 cm radio continuum and CO(J=1−0) emission, shows the same trend as that of R3−2/1−0. At the bar-end (r ~ 2.4 kpc), the amounts of molecular gas and the massive stars are enhanced when compared with other disk regions, whereas there is no excess of R3−2/1−0 and SFE in that region. This means that a simple summation of the star forming regions at the bar-end and the disk cannot reproduce the nuclear starburst of M 83, implying that the spatial variation of the dense gas fraction traced by R3−2/1−0 governs the spatial variation of SFE in M 83.

scholarly journals A High-Resolution CO Mapping of the Nucleus of the Barred-Spiral Galaxy, M83

1994 ◽  
Vol 140 ◽  
pp. 341-342 ◽  
Author(s):  
Toshihiro Handa ◽  
Sumio Ishizuki ◽  
Ryohei Kawabe
Keyword(s):  
High Resolution ◽  
Spiral Galaxy ◽  
Central Region ◽  
Molecular Gas ◽  
Nuclear Region ◽  
Circular Rotation ◽  
Frequency Coverage ◽  
Barred Spiral Galaxy ◽  
Gas Response ◽  
Co Emission

M83 is the best sample to investigate gas response to bar potential because it is one of the nearest galaxy with a pronounced bar structure (distance=3.7 Mpc). Handa et al. (1990) observed it with the Nobeyama 45-m telescope in CO(J=1-0) and found concentration of the CO emission to the dust lanes along the bar and non-circular rotation. However we need better spatial resolution in order to investigate kinematics and distribution of molecular gas in the nuclear region. So we observe the central region of M83 using the Nobeyama Millimeter Array. The synthesized beamsize was 12″ × 6″ and frequency coverage was 325 km s-1.

scholarly journals CO Multi-line Imaging of Nearby Galaxies (COMING). III. Dynamical effect on molecular gas density and star formation in the barred spiral galaxy NGC 4303

2019 ◽  
Vol 71 (Supplement_1) ◽  
Author(s):  
Yoshiyuki Yajima ◽  
Kazuo Sorai ◽  
Nario Kuno ◽  
Kazuyuki Muraoka ◽  
Yusuke Miyamoto ◽  
...  
Keyword(s):  
Star Formation ◽  
Spiral Galaxy ◽  
Galactic Disk ◽  
Molecular Gas ◽  
Kinetic Temperature ◽  
Spiral Arms ◽  
Nearby Galaxies ◽  
Barred Spiral Galaxy ◽  
Barred Spiral Galaxies ◽  
Line Imaging

AbstractWe present the results of $^{12}\textrm{C}$$\textrm{O}$(J = 1–0) and $^{13}\textrm{C}$$\textrm{O}$(J = 1–0) simultaneous mappings toward the nearby barred spiral galaxy NGC 4303 as part of the CO Multi-line Imaging of Nearby Galaxies (COMING) project. Barred spiral galaxies often show lower star-formation efficiency (SFE) in their bar region compared to the spiral arms. In this paper, we examine the relation between the SFEs and the volume densities of molecular gas n(H2) in the eight different regions within the galactic disk with $\textrm{C}$$\textrm{O}$ data combined with archival far-ultraviolet and 24 μm data. We confirmed that SFE in the bar region is lower by 39% than that in the spiral arms. Moreover, velocity-alignment stacking analysis was performed for the spectra in the individual regions. Integrated intensity ratios of $^{12}\textrm{C}$$\textrm{O}$ to $^{13}\textrm{C}$$\textrm{O}$ (R12/13) ranging from 10 to 17 were the results of this stacking. Fixing a kinetic temperature of molecular gas, $n(\rm {H_2})$ was derived from R12/13 via non-local thermodynamic equilibrium (non-LTE) analysis. The density n(H2) in the bar is lower by 31%–37% than that in the arms and there is a rather tight positive correlation between SFEs and n(H2), with a correlation coefficient of ∼0.8. Furthermore, we found a dependence of $n(\rm {H}_2)$ on the velocity dispersion of inter-molecular clouds (ΔV/sin i). Specifically, n(H2) increases as ΔV/sin i increases when ΔV/sin i &lt; 100 km s−1. On the other hand, n(H2) decreases as ΔV/sin i increases when ΔV/sin i &gt; 100 km s−1. These relations indicate that the variations of SFE could be caused by the volume densities of molecular gas, and the volume densities could be governed by the dynamical influence such as cloud–cloud collisions, shear, and enhanced inner-cloud turbulence.

Cold gas studies of a z = 2.5 protocluster

2020 ◽  
Vol 15 (S359) ◽  
pp. 136-140
Author(s):  
Minju M. Lee ◽  
Ichi Tanaka ◽  
Rohei Kawabe
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Kinematic Model ◽  
Molecular Gas ◽  
General View ◽  
Massive Galaxies ◽  
Star Forming ◽  
Gas Kinematics ◽  
Narrow Band Filter ◽  
Stellar Masses

AbstractWe present studies of a protocluster at z =2.5, an overdense region found close to a radio galaxy, 4C 23.56, using ALMA. We observed 1.1 mm continuum, two CO lines (CO (4–3) and CO (3–2)) and the lower atomic carbon line transition ([CI](3P1-3P0)) at a few kpc (0″.3-0″.9) resolution. The primary targets are 25 star-forming galaxies selected as Hα emitters (HAEs) that are identified with a narrow band filter. These are massive galaxies with stellar masses of > 1010Mʘ that are mostly on the galaxy main sequence at z =2.5. We measure the molecular gas mass from the independent gas tracers of 1.1 mm, CO (3–2) and [CI], and investigate the gas kinematics of galaxies from CO (4–3). Molecular gas masses from the different measurements are consistent with each other for detection, with a gas fraction (fgas = Mgas/(Mgas+ Mstar)) of ≃ 0.5 on average but with a caveat. On the other hand, the CO line widths of the protocluster galaxies are typically broader by ˜50% compared to field galaxies, which can be attributed to more frequent, unresolved gas-rich mergers and/or smaller sizes than field galaxies, supported by our high-resolution images and a kinematic model fit of one of the galaxies. We discuss the expected scenario of galaxy evolution in protoclusters at high redshift but future large surveys are needed to get a more general view.

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