Molecular Gas, Kinematics, and OB Star Formation in the Spiral Arms of the Southern Milky Way

2006 ◽  
Vol 641 (2) ◽  
pp. 938-948 ◽  
Author(s):  
A. Luna ◽  
L. Bronfman ◽  
L. Carrasco ◽  
J. May
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Molecular Gas ◽  
Spiral Arms ◽  
Gas Kinematics

scholarly journals Molecular Gas Kinematics and High-Mass Star Formation in the Spiral Arms of the Milky Way

2004 ◽  
Vol 191 ◽  
pp. 143-144
Author(s):  
A. Luna ◽  
L. Carrasco ◽  
L. Ortega ◽  
L. Bronfman ◽  
O. Yam
Keyword(s):  
Star Formation ◽  
Rigid Body ◽  
Large Scale ◽  
Milky Way ◽  
Stellar System ◽  
High Mass ◽  
Rotational Line ◽  
Molecular Gas ◽  
Mass Star ◽  
Spiral Arms

AbstractWe study the kinematic of the molecular gas using observations of the rotational line 12CO(J=1→0), and also the star formation traced by Ultra-Compact HII regions in the IV galactic quadrant (270° ≤ l ≤ 360°). Our results show that there is a connection between 1) high-mass star formation in the spiral arms of the Milky Way, 2) molecular gas of high column density, and 3) the large-scale rigid-body-like motion of the gas. The large-scale rigid-body-like motions observed in the arms imply that there is less angular momentum to dissipate in the formation processes of stellar systems. We show a multiple stellar system under study, embedded in its parent molecular cloud in the Carina arm region.

Perseus arm - a new perspective on star formation and spiral structure in our home galaxy

2021 ◽  
Author(s):  
M Wienen ◽  
C M Brunt ◽  
C L Dobbs ◽  
D Colombo
Keyword(s):  
Star Formation ◽  
Surface Density ◽  
Milky Way ◽  
Velocity Structure ◽  
Data Cube ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Linear Scale ◽  
Perseus Arm ◽  
Spiral Arm

Abstract Expansion of (sub)millimetre capabilities to high angular resolution offered with interferometers allows to resolve giant molecular clouds (GMCs) in nearby galaxies. This enables us to place the Milky Way in the context of other galaxies to advance our understanding of star formation in our own Galaxy. We thus remap 12CO (1 - 0) data along the Perseus spiral arm in the outer Milky Way to a fixed physical resolution and present the first spiral arm data cube at a common distance as it would be seen by an observer outside the Milky Way. To achieve this goal we calibrated the longitude-velocity structure of 12CO gas of the outer Perseus arm based on trigonometric distances and maser velocities provided by the BeSSeL survey. The molecular gas data were convolved to the same spatial resolution along the whole spiral arm and regridded on to a linear scale map with the coordinate system transformed to the spiral arm reference frame. We determined the width of the Perseus spiral arm to be 7.8 ± 0.2 km s−1 around the kinematic arm centre. To study the large scale structure we derived the 12CO gas mass surface density distribution of velocities shifted to the kinematic arm centre and arm length. This yields a variation of the gas mass surface density along the arm length and a compression of molecular gas mass at linear scale. We determined a thickness of ∼63 pc on average for the Perseus spiral arm and a centroid of the molecular layer of 8.7 pc.

scholarly journals Molecular and ionized gas kinematics in the GC Radio Arc

2016 ◽  
Vol 11 (S322) ◽  
pp. 133-136
Author(s):  
N. Butterfield ◽  
C.C. Lang ◽  
E. A. C. Mills ◽  
D. Ludovici ◽  
J. Ott ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Radio Continuum ◽  
Molecular Gas ◽  
The South ◽  
Ionized Gas ◽  
Molecular Emission ◽  
Gas Kinematics

AbstractWe present NH3 and H64α+H63α VLA observations of the Radio Arc region, including the M0.20 – 0.033 and G0.10 – 0.08 molecular clouds. These observations suggest the two velocity components of M0.20 – 0.033 are physically connected in the south. Additional ATCA observations suggest this connection is due to an expanding shell in the molecular gas, with the centroid located near the Quintuplet cluster. The G0.10 – 0.08 molecular cloud has little radio continuum, strong molecular emission, and abundant CH3OH masers, similar to a nearby molecular cloud with no star formation: M0.25+0.01. These features detected in G0.10 – 0.08 suggest dense molecular gas with no signs of current star formation.

scholarly journals Supplying Gas for Nuclear Star Formation: The Central Molecular Spiral of IC 342

1994 ◽  
Vol 140 ◽  
pp. 339-340 ◽  
Author(s):  
D. A. Levine ◽  
J. L. Turner ◽  
R. L. Hurt
Keyword(s):  
Star Formation ◽  
Spiral Galaxy ◽  
Density Wave ◽  
Wave Pattern ◽  
Molecular Gas ◽  
Spiral Arms

IC 342 is a large nearby (1.8Mpc) spiral galaxy undergoing a moderate nuclear starburst. Previous maps of the inner arc minute in 13CO (1→0) show that the nuclear molecular gas forms spiral arms approximately 500 pc in extent in a density wave pattern (Turner & Hurt, 1992).

scholarly journals Towards a multi-scale understanding of the gas-star formation cycle in the Central Molecular Zone

2016 ◽  
Vol 11 (S322) ◽  
pp. 64-74
Author(s):  
J. M. Diederik Kruijssen
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
High Redshift ◽  
Three Dimensional ◽  
Orbital Dynamics ◽  
Molecular Gas ◽  
Stellar Clusters ◽  
High Redshift Galaxies ◽  
Multi Scale ◽  
The Galaxy

AbstractThe Central Molecular Zone (CMZ, the central 500 pc of the Milky Way) contains the largest reservoir of high-density molecular gas in the Galaxy, but forms stars at a rate 10–100 times below commonly-used star formation relations. We discuss recent efforts in understanding how the nearest galactic nucleus forms its stars. The latest models of the gas inflow, star formation, and feedback duty cycle reproduce the main observable features of the CMZ, showing that star formation is episodic and that the CMZ currently resides at a star formation minimum. Using orbital modelling, we derive the three-dimensional geometry of the CMZ and show how the orbital dynamics and the star formation potential of the gas are closely coupled. We discuss how this coupling reveals the physics of star formation and feedback under the conditions seen in high-redshift galaxies, and promotes the formation of the densest stellar clusters in the Galaxy.

scholarly journals Weak CS emission in an extremely metal-poor galaxy DDO 70

2020 ◽  
Vol 496 (1) ◽  
pp. L38-L42
Author(s):  
Kaiyi Du ◽  
Yong Shi ◽  
Zhi-Yu Zhang ◽  
Junzhi Wang ◽  
Yu Gao
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Signal To Noise Ratio ◽  
Formation Rate ◽  
Far Infrared ◽  
Molecular Gas ◽  
Solar Metallicity ◽  
Low Metallicity ◽  
Co Emission

ABSTRACT In most galaxies like the Milky Way, stars form in clouds of molecular gas. Unlike the CO emission that traces the bulk of molecular gas, the rotational transitions of HCN and CS molecules mainly probe the dense phase of molecular gas, which has a tight and almost linear relation with the far-infrared luminosity and star formation rate (SFR). However, it is unclear whether dense molecular gas exists at very low metallicity, and if exists, how it is related to star formation. In this work, we report ALMA observations of the CS J = 5 → 4 emission line of DDO 70, a nearby gas-rich dwarf galaxy with $\sim \!7{{\ \rm per\ cent}}$ solar metallicity. We did not detect CS emission from all regions with strong CO emission. After stacking all CS spectra from CO-bright clumps, we find no more than a marginal detection of CS J = 5 → 4 transition, at a signal-to-noise ratio of ∼3.3. This 3σ upper limit deviates from the $L^\prime _{\rm CS}$–LIR and $L^\prime _{\rm CS}$–SFR relationships found in local star-forming galaxies and dense clumps in the Milky Way, implying weaker CS emission at given infrared luminosity and SFR. We discuss the possible mechanisms that suppress CS emission at low metallicity.

scholarly journals Lessons from comparisons between the nuclear region of the Milky Way and those in nearby spirals

2013 ◽  
Vol 9 (S303) ◽  
pp. 61-65
Author(s):  
John S. Gallagher ◽  
Tova M. Yoast-Hull ◽  
Ellen G. Zweibel
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Molecular Gas ◽  
Nuclear Region ◽  
Stellar Content ◽  
Nuclear Regions ◽  
Stellar Masses

AbstractThe Milky Way appears as a typical barred spiral, and comparisons can be made between its nuclear region and those of structurally similar nearby spirals. Maffei 2, M83, IC 342 and NGC 253 are nearby systems whose nuclear region properties contrast with those of the Milky Way. Stellar masses derived from NIR photometery, molecular gas masses and star formation rates allow us to assess the evolutionary states of this set of nuclear regions. These data suggest similarities between nuclear regions in terms of their stellar content while highlighting significant differences in current star formation rates. In particular current star formation rates appear to cover a larger range than expected based on the molecular gas masses. This behavior is consistent with nuclear region star formation experiencing episodic variations. Under this hypothesis the Milky Way's nuclear region currently may be in a low star formation rate phase.

scholarly journals Inefficient jet-induced star formation in Centaurus A

2017 ◽  
Vol 608 ◽  
pp. A98 ◽  
Author(s):  
Q. Salomé ◽  
P. Salomé ◽  
M.-A. Miville-Deschênes ◽  
F. Combes ◽  
S. Hamer
Keyword(s):  
Star Formation ◽  
Positive Feedback ◽  
Molecular Clouds ◽  
Milky Way ◽  
Data Cube ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Co Emission ◽  
Centaurus A

NGC 5128 (Centaurus A) is one of the best targets to study AGN feedback in the local Universe. At 13.5 kpc from the galaxy, optical filaments with recent star formation lie along the radio jet direction. This region is a testbed for positive feedback, here through jet-induced star formation. Atacama Pathfinder EXperiment (APEX) observations have revealed strong CO emission in star-forming regions and in regions with no detected tracers of star formation activity. In cases where star formation is observed, this activity appears to be inefficient compared to the Kennicutt-Schmidt relation. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map the 12CO(1–0) emission all along the filaments of NGC 5128 at a resolution of 1.3′′ ~ 23.8pc. We find that the CO emission is clumpy and is distributed in two main structures: (i) the Horseshoe complex, located outside the HI cloud, where gas is mostly excited by shocks and where no star formation is observed, and (ii) the Vertical filament, located at the edge of the HI shell, which is a region of moderate star formation. We identified 140 molecular clouds using a clustering method applied to the CO data cube. A statistical study reveals that these clouds have very similar physical properties, such as size, velocity dispersion, and mass, as in the inner Milky Way. However, the range of radius available with the present ALMA observations does not enable us to investigate whether or not the clouds follow the Larson relation. The large virial parameter αvir of the clouds suggests that gravity is not dominant and clouds are not gravitationally unstable. Finally, the total energy injection in the northern filaments of Centaurus A is of the same order as in the inner part of the Milky Way. The strong CO emission detected in the northern filaments is an indication that the energy injected by the jet acts positively in the formation of dense molecular gas. The relatively high virial parameter of the molecular clouds suggests that the injected kinetic energy is too strong for star formation to be efficient. This is particularly the case in the horseshoe complex, where the virial parameter is the largest and where strong CO is detected with no associated star formation. This is the first evidence of AGN positive feedback in the sense of forming molecular gas through shocks, associated with low star formation efficiency due to turbulence injection by the interaction with the radio jet.

scholarly journals Molecular gas kinematics within the central 250 pc of the Milky Way

2016 ◽  
Vol 457 (3) ◽  
pp. 2675-2702 ◽  
Author(s):  
J. D. Henshaw ◽  
S. N. Longmore ◽  
J. M. D. Kruijssen ◽  
B. Davies ◽  
J. Bally ◽  
...  
Keyword(s):  
Milky Way ◽  
Molecular Gas ◽  
Gas Kinematics

scholarly journals The SEDIGISM survey: the influence of spiral arms on the molecular gas distribution of the inner Milky Way

2021 ◽  
Author(s):  
D. Colombo ◽  
A. Duarte-Cabral ◽  
A. R. Pettitt ◽  
J. S. Urquhart ◽  
F. Wyrowski ◽  
...  
Keyword(s):  
Milky Way ◽  
Molecular Gas ◽  
Gas Distribution ◽  
Spiral Arms
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