scholarly journals 5.18. Molecular gas in the poststarburst galaxy NGC7331

1998 ◽  
Vol 184 ◽  
pp. 247-248
Author(s):  
T. Tosaki ◽  
Y. Shioya
Keyword(s):  
High Resolution ◽  
Spiral Galaxy ◽  
Stellar Populations ◽  
Optical Spectra ◽  
Molecular Gas ◽  
Early Type ◽  
Origin And Evolution ◽  
Co Observations

To understand the origin and evolution of starburst activity, we must study the full evolution of starburst; i.e., pre-, on-going, and post-starburst phases. It seems reasonable to suppose the numerous A-type stars indicate past starburst and they show strong Balmer absorption. NGC7331, nearby early-type spiral galaxy, is one of the poststarburst galaxies which show strong Balmer absorption. The optical spectra of NGC7331 were dominated by component of intermediate-age (5 × 109 years) stellar populations (Ohyama & Taniguchi 1996). We present the result of the high resolution CO observations of NGC7331 using Nobeyama Milimeter Array.

scholarly journals The Relationship Between Gas and Cirrus Dust Filaments at the Edge of the Expanding Shell in Eridanus

1990 ◽  
Vol 139 ◽  
pp. 235-236
Author(s):  
G. L. Verschuur ◽  
F. Verter ◽  
L. J. Rickard ◽  
D. T. Leisawitz
Keyword(s):  
High Resolution ◽  
Surface Brightness ◽  
Neutral Hydrogen ◽  
Scale Structure ◽  
Small Scale ◽  
Molecular Gas ◽  
Small Scale Structure ◽  
Point To Point ◽  
The Relationship ◽  
Co Observations

At the boundary of a large expanding shell in Eridanus around l = 187°, b = −50° the morphology observed in the HI emission is well mimicked by the 100 μm surface brightness but with associated structures offset by as much as 0.°5. A point-to-point comparison between I100μm and NHI in filaments of neutral hydrogen and dust (IR cirrus) produces only a weak dependence. However, when I100μm at a cirrus dust peak is compared with NHI at the associated H i peak, a relationship closer to that reported by other workers is found. Preliminary CO observations have set low limits on the molecular gas in these filaments. Since the H i and dust in our region are associated with a large expanding shell (or superbubble), shocks may be responsible for separation of gas and dust. The existence of small-scale structure in both the HI and IR is noted. We conclude that attempts to correlate HI and IR must invoke high-resolution area surveys.

HIGH-RESOLUTION OBSERVATIONS OF MOLECULAR GAS IN THE EARLY-TYPE DWARF GALAXY NGC 404

2015 ◽  
Vol 149 (6) ◽  
pp. 187 ◽  
Author(s):  
Christopher L. Taylor ◽  
Glen R. Petitpas ◽  
M. S. del Rio
Keyword(s):  
High Resolution ◽  
Dwarf Galaxy ◽  
Molecular Gas ◽  
Early Type

High-resolution CO observations of NGC 7252 - A counterrotating central molecular gas disk

1992 ◽  
Vol 396 ◽  
pp. 510 ◽  
Author(s):  
Zhong Wang ◽  
Francois Schweizer ◽  
Nicholas Z. Scoville
Keyword(s):  
High Resolution ◽  
Molecular Gas ◽  
Co Observations

scholarly journals Stellar metallicity variations across spiral arms in disk galaxies with multiple populations

2018 ◽  
Vol 611 ◽  
pp. L2 ◽  
Author(s):  
S. Khoperskov ◽  
P. Di Matteo ◽  
M. Haywood ◽  
F. Combes
Keyword(s):  
High Resolution ◽  
Spiral Galaxy ◽  
Spiral Galaxies ◽  
Stellar Populations ◽  
Disk Galaxies ◽  
Model Composite ◽  
Spiral Arms ◽  
Radial Migration ◽  
The Mean ◽  
Spiral Arm

This Letter studies the formation of azimuthal metallicity variations in the disks of spiral galaxies in the absence of initial radial metallicity gradients. Using high-resolution N-body simulations, we model composite stellar discs, made of kinematically cold and hot stellar populations, and study their response to spiral arm perturbations. We find that, as expected, disk populations with different kinematics respond differently to a spiral perturbation, with the tendency for dynamically cooler populations to show a larger fractional contribution to spiral arms than dynamically hotter populations. By assuming a relation between kinematics and metallicity, namely the hotter the population, the more metal-poor it is, this differential response to the spiral arm perturbations naturally leads to azimuthal variations in the mean metallicity of stars in the simulated disk. Thus, azimuthal variations in the mean metallicity of stars across a spiral galaxy are not necessarily a consequence of the reshaping, by radial migration, of an initial radial metallicity gradient. They indeed arise naturally also in stellar disks which have initially only a negative vertical metallicity gradient.

scholarly journals The Shaping of the Optical Jet of the Galaxy NGC 4258

1989 ◽  
Vol 120 ◽  
pp. 359-363
Author(s):  
P. Martin ◽  
J.-R. Roy ◽  
L. Noreau ◽  
K.-Y. Lo
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Spiral Galaxy ◽  
Small Angle ◽  
Aperture Synthesis ◽  
The Galaxy ◽  
Barred Spiral Galaxy ◽  
Co Observations

SUMMARY.Hα + [NII] and red continuum CCD images as well as high resolution aperture synthesis CO maps were obtained in order to study the optical jet of the barred spiral galaxy NGC 4258. The CO observations show two clouds near the center of the galaxy; these clouds outline a channel and the Hα jet follows this channel. The observations are consistent with the jet being in or making a small angle with the galaxy plane. It is concluded that the interstellar medium may play an important role in making jets detectable optically and in shaping their forms.

scholarly journals Unveiling the afterlife of galaxies with ultraviolet data

2020 ◽  
Vol 15 (S359) ◽  
pp. 467-468
Author(s):  
Ariel Werle
Keyword(s):  
Star Formation ◽  
Gini Index ◽  
Stellar Populations ◽  
Optical Spectra ◽  
Early Type ◽  
Combined Analysis ◽  
Early Results ◽  
Star Formation Histories ◽  
Red Sequence

Abstract. Recent works have shown that early-type galaxies (ETGs) are much more complex than early studies suggested. We present early results from a combined analysis of optical spectra and ultraviolet photometry for a sample of 3453 red sequence galaxies in at z < 0.1 that are classified as elliptical by Galaxy Zoo. By measuring the Gini index of the star-formation histories derived by starlight, we investigate the complexity of the mixture of stellar populations required to describe ETGs in our sample. When fitting only optical spectra, starlight assigns more or less the same mixture of stellar populations to all ETGs, while the addition of UV data unveils a bimodallity in the star-formation histories of these galaxies. We find evidence for stellar populations younger than 1 Gyr in 17 per cent of our sample, indicating that some galaxies do not stay permanently quenched after reaching the red sequence.

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 Jet-Cloud Interactions in NGC 4258: CO Observations Using the Nobeyama Millimeter Array

1994 ◽  
Vol 140 ◽  
pp. 359-360 ◽  
Author(s):  
R. L. Plante ◽  
T. Handa ◽  
K. Y. Lo
Keyword(s):  
Free Path ◽  
Spiral Galaxy ◽  
Strong Evidence ◽  
Molecular Gas ◽  
Preliminary Results ◽  
Close Relationship ◽  
Field Imaging ◽  
Co Observations

Recent CO studies of spiral galaxy NGC 4258 have revealed a close relationship between the molecular gas and the anomalous arms, recently interpreted as jets (Cecil et al. 1992, Martin et al. 1990). An IRAM single dish study by Krause et al. (1991) showed the CO to be concentrated around the Hα arms. Interferometrie imaging of the inner 1’ by Martin et al. (1990) showed the molecular gas confining the arms; they suggested that the jet had initially plowed a tunnel through the disk gas, producing a free path for subsequent ejections. This data also shows strong evidence for a jet-cloud collision along the N W arm (Piante et al. 1991).To learn more about the jets, we are motivated to exploit the jet-gas relationship with multi-field imaging of the CO along the anomalous arms using the Nobeyama Millimeter Array. We present preliminary results from our first 60” field, centered on the SE Hα arm, 43.5” from the nucleus. Observations in the two most compact configurations (C and D) produced a 4” x 6” beam.

Preliminary Observations of Interstellar Sodium D-Line Absorption towards the Carina Nebula

1980 ◽  
Vol 4 (1) ◽  
pp. 95-97 ◽  
Author(s):  
J. B. Whiteoak ◽  
F. F. Gardner
Keyword(s):  
High Resolution ◽  
Hii Regions ◽  
Early Type ◽  
Interstellar Clouds ◽  
Carina Nebula ◽  
Line Absorption ◽  
General Investigation ◽  
Early Type Stars ◽  
Resolution Study

As part of a general investigation of interstellar clouds associated with southern HII regions we have begun a high-resolution study of the sodium D-line absorption in the directions of early-type stars that are likely to be associated with or located behind the clouds.

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