scholarly journals More insights into bar quenching

2020 ◽  
Vol 644 ◽  
pp. A79
Author(s):  
K. George ◽  
P. Joseph ◽  
C. Mondal ◽  
S. Subramanian ◽  
A. Subramaniam ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Hydrogen ◽  
Neutral Hydrogen ◽  
Archival Data ◽  
Imaging Data ◽  
Gas Distribution ◽  
Barred Galaxies ◽  
Central Regions ◽  
Multi Wavelength ◽  
Disc Galaxies

The underlying nature of the process of star formation quenching in the central regions of barred disc galaxies that is due to the action of stellar bar is not fully understood. We present a multi-wavelength study of four barred galaxies using the archival data from optical, ultraviolet, infrared, CO, and HI imaging data on star formation progression and stellar and gas distribution to better understand the process of bar quenching. We found that for three galaxies, the region between the nuclear or central sub-kiloparsec region and the end of the bar (bar region) is devoid of neutral and molecular hydrogen. While the detected neutral hydrogen is very negligible, we note that molecular hydrogen is present abundantly in the nuclear or central sub-kiloparsec regions of all four galaxies. The bar co-rotation radius is also devoid of recent star formation for three out of four galaxies. One galaxy shows significant molecular hydrogen along the bar, which might mean that the gas is still being funnelled to the centre by the action of the stellar bar. Significant star formation is also present along the bar co-rotation radius of this galaxy. The study presented here supports a scenario in which gas redistribution as a result of the action of stellar bar clears the bar region of fuel for further star formation and eventually leads to star formation quenching in the bar region.

scholarly journals Star formation properties in barred galaxies

2011 ◽  
Vol 7 (S284) ◽  
pp. 349-351
Author(s):  
Zhi-Min Zhou ◽  
Chen Cao ◽  
Hong Wu
Keyword(s):  
Star Formation ◽  
Central Region ◽  
Barred Galaxies ◽  
Secular Evolution ◽  
Evolution Of Galaxies ◽  
Star Formation Activity ◽  
Multi Wavelength

AbstractStellar bars are important structures for the internal secular evolution of galaxies. They can drive gas into the central region of galaxies, and result in an enhancement of star formation activity there. Previous studies are limited in the comparisons between barred and unbarred galaxies. Here we try to investigate the connection between star formation activities and different bars, based on multi-wavelength data in a sample of barred spirals. We find that there is no clearly trend of the surface star formation rates in different structures along the bar strength. In addition, there is larger scatter for the properties of star formation activity in the galaxies with middle-strength bars, which may indicate that a variety of star formation stages are more likely associated with these bars.

scholarly journals Molecular Gas in the Central Regions of Barred Galaxies

1996 ◽  
Vol 157 ◽  
pp. 150-156 ◽  
Author(s):  
Jeffrey Kenney
Keyword(s):  
Star Formation ◽  
Solid Body ◽  
Rotation Curve ◽  
Molecular Gas ◽  
Star Forming ◽  
Barred Galaxies ◽  
Central Regions ◽  
Early Phases ◽  
Intense Star Formation

AbstractThe morphology and kinematics of molecular gas in the central regions of barred galaxies are described. The largest gas concentrations are often located near ILRs, although there is a range of morphologies. The gas motions associated with star-forming rings are predominantly circular, while motions just beyond the rings are often non-circular and in some cases show clear radial inflow. In barred galaxies with circumnuclear starbursts in early phases of evolution, the CO is centrally peaked, perhaps inside IILRs. The most intense star formation occurs where the gas motions are circular, and where the rotation curve rises steeply and is nearly solid body.

scholarly journals Star Formation in Young Cluster NGC 1893

2007 ◽  
Vol 3 (S246) ◽  
pp. 73-74
Author(s):  
Saurabh Sharma ◽  
A. K. Pandey ◽  
D. K. Ojha ◽  
W. P. Chen ◽  
S. K. Ghosh ◽  
...  
Keyword(s):  
Star Formation ◽  
Narrow Band ◽  
Massive Stars ◽  
Broad Band ◽  
Archival Data ◽  
Mass Star ◽  
Star Forming ◽  
Multi Wavelength ◽  
Low Mass

AbstractWe have carried out a multi-wavelength study of the star forming region NGC 1893 to make a comprehensive exploration of the effects of massive stars on low mass star formation. Using deep optical U BV RI broad band, Hα narrow band photometry and slit-less spectroscopy along with archival data from the surveys such as 2MASS, MSX, IRAS and NVSS, we have studied the region to understand the star formation scenario in the region.

scholarly journals Multi-wavelength study of star formation properties in barred galaxies

2012 ◽  
Vol 8 (S295) ◽  
pp. 323-323
Author(s):  
Zhi-Min Zhou ◽  
Chen Cao ◽  
Hong Wu
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Evolutionary Sequence ◽  
Barred Galaxies ◽  
Secular Evolution ◽  
Density Distributions ◽  
Complex Process ◽  
Multi Wavelength ◽  
Galactic Structures ◽  
Future Work

AbstractStellar bars are important internal drivers of the secular evolution of disk galaxies. Using a sample of nearby barred galaxies with weak and strong bars, we evaluate the correlations between star formation properties in different galactic structures and their associated bars, and try to interpret the complex process of bar-driven secular evolution. We find that weaker bars tend to associate with lower concentrical star formation activities, while stronger bars appear to have large scatter in the distribution of the global star formation activities. In general, the star formation activities in early- and late-type galaxies have different behavior, with similar star formation rate density distributions. In addition, there are only weak trends toward increased star formation activities in bulges and galaxies with stronger bars, which is consistent with previous works. Our results suggest that the different stages of the evolutionary sequence and many factors besides bars may contribute to the complexity of this process. Furthermore, significant correlations are found between the star formation activities in different galactic structures, in which barred galaxies with intense star formation in bulges tend to also have active star formation in their bars and disks. Most bulges have higher star formation densities than their associated bars and disks, indicating the presence of bar-driven evolution. Therefore, we derived a possible criterion (Figure 1) to quantify the different stages of a bar-driven evolutionary sequence. Future work is needed to improve on the uncertainties of this study.

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.

scholarly journals The H i morphology and stellar properties of strongly barred galaxies: support for bar quenching in massive spirals

2020 ◽  
Vol 492 (4) ◽  
pp. 4697-4715 ◽  
Author(s):  
L Newnham ◽  
Kelley M Hess ◽  
Karen L Masters ◽  
Sandor Kruk ◽  
Samantha J Penny ◽  
...  
Keyword(s):  
Star Formation ◽  
Sloan Digital Sky Survey ◽  
Optical Data ◽  
Star Forming ◽  
Barred Galaxies ◽  
Stellar Properties ◽  
Open Question ◽  
Star Formation Histories ◽  
Gas Fractions ◽  
Disc Galaxies

ABSTRACT Galactic bars are able to affect the evolution of galaxies by redistributing their gas, possibly contributing to the cessation of star formation. Several recent works point to ‘bar quenching’ playing an important role in massive disc galaxies. We construct a sample of six gas-rich and strongly barred disc galaxies with resolved H i observations. This sample of galaxies, which we call H i-rich barred galaxies, was identified with the help of Galaxy Zoo to find galaxies hosting a strong bar, and the Arecibo Legacy Fast Arecibo L-band Feed Array blind H i survey to identify galaxies with a high H i content. The combination of strong bar and high gas fraction is rare, so this set of six galaxies is the largest sample of its type with resolved H i observations. We measure the gas fractions, H i morphology and kinematics, and use archival optical data from the Sloan Digital Sky Survey to reveal star formation histories and bar properties. The galaxies with the lowest gas fractions (still very high for their mass) show clear H i holes, dynamically advanced bars, and low star formation rates, while those with the highest gas fractions show little impact from their bar on the H i morphology, and are still actively star-forming. These galaxies support a picture in which the movement of gas by bars can lead to star formation quenching. How these unusual galaxies came to be is an open question.

scholarly journals Redistribution of stars and gas in the star formation deserts of barred galaxies

2019 ◽  
Vol 489 (4) ◽  
pp. 4992-5003 ◽  
Author(s):  
C E Donohoe-Keyes ◽  
M Martig ◽  
P A James ◽  
K Kraljic
Keyword(s):  
Star Formation ◽  
Time Scales ◽  
Age Distribution ◽  
Young Stars ◽  
Host Galaxies ◽  
Radial Migration ◽  
Barred Galaxies ◽  
Central Regions ◽  
Zoom In ◽  
Bar Formation

ABSTRACT Bars strongly influence the distribution of gas and stars within the central regions of their host galaxies. This is particularly pronounced in the star formation desert (SFD) which is defined as two symmetrical regions either side of the bar that show a deficit in young stars. Previous studies proposed that, if star formation is truncated because of the influence of the bar, then the age distribution of stars within the SFD could be used to determine the epoch of bar formation. To test this, we study the properties of SFDs in six galaxies from zoom-in cosmological re-simulations. Age maps reveal old regions on both sides of the bars, with a lack of stars younger than 10 Myr, confirming the SFD phenomenon. Local star formation is truncated in the SFDs because after the bar forms, gas in these regions is removed on 1 Gyr time-scales. However, the overall age distribution of stars in the SFD does not show a sharp truncation after bar formation but rather a gradual downturn in comparison to that of the bar. This more subtle signature may still give information on bar formation epochs in observed galaxies, but the interpretation will be more difficult than originally hoped. The gradual drop in the SFD age distribution, instead of a truncation, is due to radial migration of stars born in the disc. The SFD is thus one of the only regions where an uncontaminated sample of stars only affected by radial migration can be studied.

scholarly journals The Local Universe: Galaxies in 3D

2014 ◽  
Vol 10 (S309) ◽  
pp. 39-46
Author(s):  
Bärbel S. Koribalski
Keyword(s):  
Star Formation ◽  
Neutral Hydrogen ◽  
Hydrogen Gas ◽  
Local Universe ◽  
Galaxy Surveys ◽  
Spatially Resolved ◽  
The Galaxy ◽  
Multi Wavelength ◽  
Large Survey ◽  
Individual Galaxy

AbstractHere I present results from individual galaxy studies and galaxy surveys in the Local Universe with particular emphasis on the spatially resolved properties of neutral hydrogen gas. The 3D nature of the data allows detailed studies of the galaxy morphology and kinematics, their relation to local and global star formation as well as galaxy environments. I use new 3D visualisation tools to present multi-wavelength data, aided by tilted-ring models of the warped galaxy disks. Many of the algorithms and tools currently under development are essential for the exploration of upcoming large survey data, but are also highly beneficial for the analysis of current galaxy surveys.

scholarly journals Ionization compression impact on dense gas distribution and star formation

2014 ◽  
Vol 564 ◽  
pp. A106 ◽  
Author(s):  
P. Tremblin ◽  
N. Schneider ◽  
V. Minier ◽  
P. Didelon ◽  
T. Hill ◽  
...  
Keyword(s):  
Star Formation ◽  
Dense Gas ◽  
Gas Distribution

scholarly journals Composite bulges – II. Classical bulges and nuclear discs in barred galaxies: the contrasting cases of NGC 4608 and NGC 4643

2021 ◽  
Vol 502 (2) ◽  
pp. 2446-2473
Author(s):  
Peter Erwin ◽  
Anil Seth ◽  
Victor P Debattista ◽  
Marja Seidel ◽  
Kianusch Mehrgan ◽  
...  
Keyword(s):  
Large Scale ◽  
Stellar Kinematics ◽  
Barred Galaxies ◽  
Circular Structure ◽  
Model Predictions ◽  
The Galaxy ◽  
Central Regions ◽  
Total Light ◽  
Kinematic Analyses ◽  
Stellar Kinematic

ABSTRACT We present detailed morphological, photometric, and stellar-kinematic analyses of the central regions of two massive, early-type barred galaxies with nearly identical large-scale morphologies. Both have large, strong bars with prominent inner photometric excesses that we associate with boxy/peanut-shaped (B/P) bulges; the latter constitute ∼30 per cent of the galaxy light. Inside its B/P bulge, NGC 4608 has a compact, almost circular structure (half-light radius Re ≈ 310 pc, Sérsic n = 2.2) we identify as a classical bulge, amounting to 12.1 per cent of the total light, along with a nuclear star cluster (Re ∼ 4 pc). NGC 4643, in contrast, has a nuclear disc with an unusual broken-exponential surface-brightness profile (13.2 per cent of the light), and a very small spheroidal component (Re ≈ 35 pc, n = 1.6; 0.5 per cent of the light). IFU stellar kinematics support this picture, with NGC 4608’s classical bulge slowly rotating and dominated by high velocity dispersion, while NGC 4643’s nuclear disc shows a drop to lower dispersion, rapid rotation, V–h3 anticorrelation, and elevated h4. Both galaxies show at least some evidence for V–h3correlation in the bar (outside the respective classical bulge and nuclear disc), in agreement with model predictions. Standard two-component (bulge/disc) decompositions yield B/T ∼ 0.5–0.7 (and bulge n > 2) for both galaxies. This overestimates the true ‘spheroid’ components by factors of 4 (NGC 4608) and over 100 (NGC 4643), illustrating the perils of naive bulge-disc decompositions applied to massive barred galaxies.

Sign in / Sign up

Export Citation Format

Share Document