scholarly journals HI Study of the NGC 6744 System

1999 ◽  
Vol 16 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Stuart D. Ryder ◽  
Wilfred Walsh ◽  
David Malin
Keyword(s):  
Velocity Field ◽  
Spiral Galaxy ◽  
Neutral Hydrogen ◽  
Optical Disk ◽  
Mass Model ◽  
Spiral Arms ◽  
Preliminary Results ◽  
Heliocentric Velocity ◽  
Compact Array

AbstractWe present the preliminary results of our 5-configuration, 20-pointing mosaic with the Australia Telescope Compact Array of the neutral hydrogen in the nearby spiral galaxy NGC 6744. The bulk of the HI resides in a ‘ring’ underlying the outer optical disk, with 2 HI spiral arms extending further out to almost 1·5 optical radii. The velocity field is fairly regular, apart from evidence for streaming motions along the HI arms, and the influence of the companion IB(s)m galaxy NGC 6744A. We associate a cloud of HI at a heliocentric velocity of 846 km s−1 with another companion object, ESO 104–g44. Our attempts to construct a mass model for NGC 6744 suffer from poor resolution in the inner disk, and the uncertainty in the total HI flux of NGC 6744. We anticipate that HIPASS observations will be crucial in resolving the latter issue.

scholarly journals The HI in the Large Barred Spiral NGC 1365

1996 ◽  
Vol 157 ◽  
pp. 168-171 ◽  
Author(s):  
S. Jörsäter ◽  
G. A. van Moorsel
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Spiral Galaxy ◽  
Rotation Curve ◽  
Spiral Arms ◽  
Barred Spiral Galaxy ◽  
Inner Parts ◽  
Ngc 1365

AbstractWe have made high resolution HI observations using the VLA1 of the barred spiral galaxy NGC 1365. This galaxy contains 15.2 × 109M⊙ of HI. The velocity field is strongly affected by the bar only in the inner parts. NGC 1365 has a warp and it has 4 well developed spiral arms and 2 rudimentary ones. NGC 1365 has an unusually dropping rotation curve.

scholarly journals Discovery of Extraplanar H i Clouds and a H i Tail in the M101 Galaxy Group with FAST

2021 ◽  
Vol 922 (1) ◽  
pp. 53
Author(s):  
Jin-Long Xu ◽  
Chuan-Peng Zhang ◽  
Naiping Yu ◽  
Ming Zhu ◽  
Peng Jiang ◽  
...  
Keyword(s):  
Velocity Field ◽  
Radio Telescope ◽  
Spiral Galaxy ◽  
High Sensitivity ◽  
Optical Disk ◽  
Outer Disk ◽  
The Masses ◽  
A Minor ◽  
Disk Region ◽  
Strong Disturbance

Abstract We present a new high-sensitivity H i observation toward nearby spiral galaxy M101 and its adjacent 2° × 2° region using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From the observation, we detect a more extended and asymmetric H i disk around M101. While the H i velocity field within the M101's optical disk region is regular, indicating that the relatively strong disturbance occurs in its outer disk. Moreover, we identify three new H i clouds located on the southern edge of the M101's H i disk. The masses of the three H i clouds are 1.3 × 107 M ⊙, 2.4 × 107 M ⊙, and 2.0 × 107 M ⊙, respectively. The H i clouds similar to dwarf companion NGC 5477 rotate with the H i disk of M101. Unlike NGC 5477, they have no optical counterparts. Furthermore, we detect a new H i tail in the extended H i disk of M101. The H i tail detected gives reliable evidence for M101 interaction with the dwarf companion NGC 5474. We argue that the extraplanar gas (three H i clouds) and the H i tail detected in the M101's disk may originate from a minor interaction with NGC 5474.

scholarly journals High Resolution Observations of Neutral Hydrogen in M33 - II: THE VELOCITY FIELD

1973 ◽  
Vol 163 (2) ◽  
pp. 163-182 ◽  
Author(s):  
P. J. Warner ◽  
M. C. H. Wright ◽  
J. E. Baldwin
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Neutral Hydrogen

scholarly journals An HI Mosaic of the Large Magellanic Cloud

1997 ◽  
Vol 14 (1) ◽  
pp. 119-121 ◽  
Author(s):  
Sungeun Kim ◽  
K. C. Freeman ◽  
L. Staveley-Smith ◽  
R. J. Sault ◽  
M. J. Kesteven ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Neutral Hydrogen ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Compact Array

AbstractThe parameters of a new Australia Telescope Compact Array (ATCA) mosaic of the Large Magellanic Cloud (LMC) in the 21-cm line of neutral hydrogen are described. A preliminary peak-brightness-temperature image of the whole of the LMC, and a detailed image of the region around the supergiant shells LMC 4 and 5 is shown.

scholarly journals New light on the corrugation phenomenon in our Galaxy

1985 ◽  
Vol 106 ◽  
pp. 175-178
Author(s):  
J. V. Feitzinger ◽  
J. Spicker
Keyword(s):  
Velocity Field ◽  
Radial Velocity ◽  
Density Wave ◽  
Radial Expansion ◽  
Spiral Pattern ◽  
Mass Model ◽  
Wave Kinematics ◽  
Spiral Arm

This investigation presents a total picture of the well-known corrugation-phenomenon for the (heliocentric) longitude range 10° ≤ 1 ≤ 240° as derived from HI-studies. For each spiral arm of the spiral pattern of Simonson (1976), we derived the centroid of the HI distribution from the 21-cm line surveys of Weaver and Williams (1974), Sinha (1979), and Westerhout and Wendlandt (1982). The three-component mass model of Rohlfs and Kreitschmann (1981) was used to derive a radial-velocity field, which was supplemented by a radial expansion field and by density-wave kinematics. This combined field served to calculated kinematic distances. The warp was taken into account according to Henderson et al. (1982) and Kulkarni et al. (1982).

scholarly journals The imprint of arms and bars on rotation curves: in-plane and off-plane

2020 ◽  
Vol 496 (2) ◽  
pp. 1845-1856
Author(s):  
Luis A Martinez-Medina ◽  
Barbara Pichardo ◽  
Antonio Peimbert
Keyword(s):  
Spiral Galaxy ◽  
Pitch Angle ◽  
Local Minima ◽  
Late Type ◽  
Rotation Curves ◽  
Spiral Arms ◽  
Stellar Disc ◽  
Secular Evolution ◽  
Galaxy Model ◽  
Characteristic Features

ABSTRACT Within rotation curves (RCs) is encoded the kinematical state of the stellar disc as well as information about the dynamical mechanisms driving the secular evolution of galaxies. To explain the characteristic features of RCs which arise by the influence of spiral patterns and bar, we study the kinematics of the stellar disc in a set of spiral galaxy models specifically tailored for this purpose. We find that, for our models, the induced non-circular motions are more prominent for spirals with larger pitch angle, the ones typical in late-type galaxies. Moreover, inside corotation, stars rotate slower along the spiral arms than along the interarm, which translates into a local minima or maxima in the RC, respectively. We also see, from off-plane RC, that the rotation is faster for stars that at observed closer to the plane, and diminishes as one looks farther off plane; this trend is more noticeable in our Sa galaxy model than our Sc galaxy model. Additionally, in a previous work we found that the diagonal ridges in the Vϕ–R plane, revealed through the GaiaDR2, have a resonant origin due to the spiral arms and bar and that these ridges project themselves as wiggles in the RC; here, we further notice that the development of these ridges, and the development of high orbital eccentricities in the stellar disc are the same. Hence, we conclude that, the following explanations of bumps and wiggles in RCs are equivalent: they are manifestations of diagonal ridges in the Vϕ–R plane, or of the rearrangement of the orbital eccentricities in the stellar disc.

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 Radio planetary nebulae in the Magellanic Clouds

2011 ◽  
Vol 7 (S283) ◽  
pp. 334-335 ◽  
Author(s):  
Evan J. Crawford ◽  
Miroslav D. Filipović ◽  
Ivan S. Bojičić ◽  
Martin Cohen ◽  
Jeff L. Payne ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Magellanic Clouds ◽  
Radio Continuum ◽  
Preliminary Results ◽  
Compact Array

AbstractWe present preliminary results of our deep Australia Telescope Compact Array (ATCA) radio-continuum survey of the Magellanic Clouds Planetary Nebulae.

The velocity field of the barred spiral galaxy NGC 5383

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

scholarly journals Neutral Hydrogen in the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 37-44
Author(s):  
L. Staveley-Smith ◽  
S. Kim ◽  
S. Stanimirović
Keyword(s):  
Atomic Hydrogen ◽  
Large Scale ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Distribution Functions ◽  
Magellanic Clouds ◽  
Self Gravity ◽  
Rotational Shear ◽  
Compact Array

We review observations of neutral atomic hydrogen (HI) in the Magellanic Clouds (MCs). Being the nearest gas-rich neighbours of the Milky Way the MCs give us an excellent opportunity to study in detail the structure and evolution of the interstellar medium (ISM) and the effect of interactions between galaxies. HI in emission provides a probe of the structure and velocity field of the Clouds, allowing the study of their velocity dispersion, 3-D structure, and large-scale total-mass distribution. Recent data from Australia Telescope Compact Array surveys reveal a morphology (for both Clouds) which is heavily dominated by the effects of local star-formation, rotational shear, fragmentation, self-gravity and turbulence. The new data, which has a spatial resolution down to 10 pc, also allows the study of the distribution functions in velocity and mass for HI clouds. We discuss the morphology, dynamics and giant shell population of the LMC and SMC.

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