scholarly journals Wolf-Rayet stars and an extraordinary star-forming region in the barred spiral galaxy NGC 5430 deg

1982 ◽  
Vol 94 ◽  
pp. 765 ◽  
Author(s):  
W. C. Keel
2010 ◽  
Vol 27 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Stuart D. Ryder ◽  
Samuel M. Illingworth ◽  
Robert G. Sharp ◽  
Catherine L. Farage

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°.


1999 ◽  
Vol 511 (1) ◽  
pp. 157-177 ◽  
Author(s):  
Kotaro Kohno ◽  
Ryohei Kawabe ◽  
Baltasar Vila‐Vilaro

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.


1998 ◽  
Vol 184 ◽  
pp. 141-142
Author(s):  
K. Sorai ◽  
N. Nakai ◽  
N. Kuno ◽  
K. Nishiyama

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)).


2020 ◽  
Vol 634 ◽  
pp. A124 ◽  
Author(s):  
M. Bellazzini ◽  
F. Annibali ◽  
M. Tosi ◽  
A. Mucciarelli ◽  
M. Cignoni ◽  
...  

We present the first analysis of the stellar content of the structures and substructures identified in the peculiar star-forming galaxy NGC 5474, based on Hubble Space Telescope resolved photometry from the LEGUS survey. NGC 5474 is a satellite of the giant spiral M 101, and it is known to have a prominent bulge that is significantly off-set from the kinematic centre of the underlying H I and stellar disc. The youngest stars (age ≲ 100 Myr) trace a flocculent spiral pattern extending out to ≳8 kpc from the centre of the galaxy. On the other hand, intermediate-age (age ≳ 500 Myr) and old (age ≳ 2 Gyr) stars dominate the off-centred bulge and a large substructure residing in the south-western part of the disc (SW over-density) and they are not correlated with the spiral arms. The old age of the stars in the SW over-density suggests that this may be another signature of any dynamical interactions that have shaped this anomalous galaxy. We suggest that a fly by with M 101, generally invoked as the origin of the anomalies, may not be sufficient to explain all the observations. A more local and more recent interaction may help to put all the pieces of this galactic puzzle together.


1996 ◽  
Vol 157 ◽  
pp. 164-167
Author(s):  
S. N. Dodonov

AbstractIntegral Field Spectrograph observations of southeast (SE) gas outflow in the center (11×13 arcsec) of NGC 4258 with spatial sampling 0.6 and 1.2 arcsec were made with the 6-m Telescope. Reconstructed spatial and kinematic structure of the SE outflow from 20-30 pc to 200-220 pc are presented.


1991 ◽  
Vol 101 ◽  
pp. 825 ◽  
Author(s):  
Jean-Rene Roy ◽  
Jianguo Wang ◽  
Robin Arsenault

1978 ◽  
Vol 219 ◽  
pp. 31 ◽  
Author(s):  
C. J. Peterson ◽  
N. Thonnard ◽  
V. C. Rubin ◽  
W. K., Jr. Ford

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