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 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 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 Shocked Molecular Hydrogen from Star Forming Regions

1987 ◽  
Vol 115 ◽  
pp. 181-181 ◽  
Author(s):  
Adair P. Lane ◽  
John Bally
Keyword(s):  
Shock Waves ◽  
High Velocity ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Young Stars ◽  
Emission Lines ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Post Shock

Near infrared (2 micron) emission lines from molecular hydrogen provide a powerful probe of the morphology and energetics of outflows associated with stellar birth. The H2 emission regions trace the location of shock waves formed when the high velocity outflow from young stars encounters dense quiescent gas. Since H2 is the dominant coolant of the hot post-shock molecular gas, the H2 lines provide a measure of the fraction of the total mechanical luminosity radiated away from the cloud.

scholarly journals Spatial Variation of CO Excitation in High-z Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 253-253
Author(s):  
Chelsea E. Sharon ◽  
Andrew J. Baker ◽  
Andrew I. Harris ◽  
Dieter Lutz ◽  
Linda J. Tacconi
Keyword(s):  
Spatial Variation ◽  
Gravitational Lensing ◽  
Early Stage ◽  
High Redshift ◽  
Molecular Gas ◽  
Very Large Array ◽  
Star Forming ◽  
Spatially Extended ◽  
Frequency Coverage ◽  
Extended Sources

AbstractPrevious studies of the molecular gas excitation in high-redshift galaxies have focused on galaxy-wide averages of CO line ratios. However, it is possible that these averages hide spatial variation on sub-galactic scales, disguising the true distribution and conditions of the molecular gas within star-forming galaxies. Even in the pre-ALMA era we have begun to see evidence for spatial variation of CO excitation in both rest-UV selected and submillimeter-selected galaxies at z > 2, aided both by the increased frequency coverage of the Jansky Very Large Array (allowing high-resolution observations of the CO(1–0) line, the best tracer for the coldest molecular gas) and by the benefits of gravitational lensing for spatially extended sources. We show new results for multiple high-redshift systems that reveal spatial and/or spectral variations in CO excitation, including an early-stage merger that has different conditions in its two components, thereby illustrating the need for high spatial and spectral resolution mapping in order to accurately characterize the molecular ISM in high-z galaxies.

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°.

scholarly journals Insights on bar quenching from a multiwavelength analysis: The case of Messier 95

2019 ◽  
Vol 621 ◽  
pp. L4 ◽  
Author(s):  
K. George ◽  
P. Joseph ◽  
C. Mondal ◽  
S. Subramanian ◽  
A. Subramaniam ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Hydrogen ◽  
Stellar Population ◽  
Major Axis ◽  
Nuclear Region ◽  
Imaging Data ◽  
Physical Processes ◽  
Star Forming ◽  
The Galaxy ◽  
Barred Spiral Galaxy

The physical processes related to the effect of bars in the quenching of star formation in the region between the nuclear/central sub-kiloparsec region and the ends of the bar (bar region) of spiral galaxies is not fully understood. It is hypothesized that the bar can either stabilize the gas against collapse, inhibiting star formation, or efficiently consume all the available gas, leaving no fuel for further star formation. We present a multiwavelength study using the archival data of an early-type barred spiral galaxy, Messier 95, which shows signatures of suppressed star formation in the bar region. Using optical, ultraviolet (UV), infrared, CO, and HI imaging data we study the pattern of star formation progression and stellar/gas distribution, and try to provide insights into the process responsible for the observed pattern. The FUV–NUV pixel colour map reveals a cavity devoid of UV flux in the bar region that matches the length of the bar, which is ∼4.2 kpc. The central nuclear region of the galaxy shows a blue colour clump and along the major axis of the stellar bar the colour progressively becomes redder. Based on a comparison to single stellar population models, we show that the region of galaxy along the major axis of the bar, unlike the region outside the bar, is comprised of stellar populations with ages ≥350 Myr; there is a star-forming clump in the centre of younger ages of ∼150 Myr. Interestingly the bar region is also devoid of neutral and molecular hydrogen but has an abundant molecular hydrogen present at the nuclear region of the galaxy. Our results are consistent with a picture in which the stellar bar in Messier 95 is redistributing the gas by funnelling gas inflows to nuclear region, thus making the bar region devoid of fuel for star formation.

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
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