scholarly journals Erratum: “Circumnuclear Star Formation in the Early-Type Resonance Ring Barred Spiral Galaxy NGC 1326” [[URL ADDRESS="/cgi-bin/resolve?2000AJ....120.1289B" STATUS="OKAY"]Astron. J. [BF]120[/BF], 1289 (2000)[/URL]]

2001 ◽  
Vol 122 (5) ◽  
pp. 2785-2785
Author(s):  
R. Buta ◽  
Patrick M. Treuthardt ◽  
G. G. Byrd ◽  
D. A. Crocker
2000 ◽  
Vol 120 (3) ◽  
pp. 1289-1305 ◽  
Author(s):  
R. Buta ◽  
Patrick M. Treuthardt ◽  
G. G. Byrd ◽  
D. A. Crocker

2016 ◽  
Vol 461 (2) ◽  
pp. 1684-1700 ◽  
Author(s):  
Yusuke Fujimoto ◽  
Greg L. Bryan ◽  
Elizabeth J. Tasker ◽  
Asao Habe ◽  
Christine M. Simpson

Science ◽  
2019 ◽  
Vol 365 (6452) ◽  
pp. 478-482 ◽  
Author(s):  
Dorota M. Skowron ◽  
Jan Skowron ◽  
Przemek Mróz ◽  
Andrzej Udalski ◽  
Paweł Pietrukowicz ◽  
...  

The Milky Way is a barred spiral galaxy, with physical properties inferred from various tracers informed by the extrapolation of structures seen in other galaxies. However, the distances of these tracers are measured indirectly and are model-dependent. We constructed a map of the Milky Way in three dimensions, based on the positions and distances of thousands of classical Cepheid variable stars. This map shows the structure of our Galaxy’s young stellar population and allows us to constrain the warped shape of the Milky Way’s disk. A simple model of star formation in the spiral arms reproduces the observed distribution of Cepheids.


2007 ◽  
Vol 59 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Kazuyuki Muraoka ◽  
Kotaro Kohno ◽  
Tomoka Tosaki ◽  
Nario Kuno ◽  
Kouichiro Nakanishi ◽  
...  

2019 ◽  
Vol 488 (4) ◽  
pp. 4674-4689 ◽  
Author(s):  
Fiorenzo Vincenzo ◽  
Chiaki Kobayashi ◽  
Tiantian Yuan

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.


2010 ◽  
Vol 721 (1) ◽  
pp. 383-394 ◽  
Author(s):  
Rieko Momose ◽  
Sachiko K. Okumura ◽  
Jin Koda ◽  
Tsuyoshi Sawada

2019 ◽  
Vol 71 (Supplement_1) ◽  
Author(s):  
Yoshiyuki Yajima ◽  
Kazuo Sorai ◽  
Nario Kuno ◽  
Kazuyuki Muraoka ◽  
Yusuke Miyamoto ◽  
...  

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 < 100 km s−1. On the other hand, n(H2) decreases as ΔV/sin i increases when ΔV/sin i > 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.


2012 ◽  
Vol 8 (S295) ◽  
pp. 354-357
Author(s):  
Peter H. Johansson

AbstractWe demonstrate that massive simulated galaxies assemble in two phases, with the initial growth dominated by compact in situ star formation, whereas the late growth is dominated by accretion of old stars formed in subunits outside the main galaxy. We also show that 1) gravitational feedback strongly suppresses late star formation in massive galaxies contributing to the observed galaxy colour bimodality that 2) the observed galaxy downsizing can be explained naturally in the two-phased model and finally that 3) the details of the assembly histories of massive galaxies are directly connected to their observed kinematic properties.


2008 ◽  
Vol 4 (S258) ◽  
pp. 61-72
Author(s):  
Monica Tosi

AbstractThe colour-magnitude diagrams of resolved stellar populations are the best tool to study the star formation histories of the host galactic regions. In this review the method to derive star formation histories by means of synthetic colour-magnitude diagrams is briefly outlined, and the results of its application to resolved galaxies of various morphological types are summarized. It is shown that all the galaxies studied so far were already forming stars at the lookback time reached by the observational data, independently of morphological type and metallicity. Early-type galaxies have formed stars predominantly, but in several cases not exclusively, at the earliest epochs. All the other galaxies appear to have experienced rather continuous star formation activities throughout their lifetimes, although with significant rate variations and, sometimes, short quiescent phases.


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