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 SDSS-IV MaNGA: the indispensable role of bars in enhancing the central star formation of low-z galaxies

2020 ◽  
Vol 499 (1) ◽  
pp. 1406-1423 ◽  
Author(s):  
Lin Lin ◽  
Cheng Li ◽  
Cheng Du ◽  
Enci Wang ◽  
Ting Xiao ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Local Environment ◽  
Central Star ◽  
Barred Galaxies ◽  
Secular Evolution ◽  
Integral Field Spectroscopy ◽  
Radial Profiles ◽  
Order Of Magnitude

ABSTRACT We analyse two-dimensional maps and radial profiles of EW(Hα), EW(HδA), and Dn(4000) of low-redshift galaxies using integral field spectroscopy from the MaNGA survey. Out of ≈1400 nearly face-on late-type galaxies with a redshift z < 0.05, we identify 121 “turnover” galaxies that each have a central upturn in EW(Hα), EW(HδA), and/or a central drop in Dn(4000), indicative of ongoing/recent star formation. The turnover features are found mostly in galaxies with a stellar mass above ∼1010 M⊙ and NUV – r colour less than ≈5. The majority of the turnover galaxies are barred, with a bar fraction of 89 ± 3 per cent. Furthermore, for barred galaxies, the radius of the central turnover region is found to tightly correlate with one-third of the bar length. Comparing the observed and the inward extrapolated star formation rate surface density, we estimate that the central SFR have been enhanced by an order of magnitude. Conversely, only half of the barred galaxies in our sample have a central turnover feature, implying that the presence of a bar is not sufficient to lead to a central SF enhancement. We further examined the SF enhancement in paired galaxies, as well as the local environment, finding no relation. This implies that the environment is not a driving factor for central SF enhancement in our sample. Our results reinforce both previous findings and theoretical expectation that galactic bars play a crucial role in the secular evolution of galaxies by driving gas inflow and enhancing the star formation and bulge growth in the centre.

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 The HerMES Local Luminosity Function

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Lucia Marchetti ◽  
Mattia Vaccari ◽  
Alberto Franceschini
Keyword(s):  
Star Formation ◽  
Data Fusion ◽  
Luminosity Function ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Accurate Determination ◽  
Far Infrared ◽  
Rate Function ◽  
Model Predictions ◽  
Multi Wavelength

AbstractWe exploit the Herschel Extragalactic Multi-Tiered Survey (HerMES) dataset along with ancillary multi-wavelength photometry and spectroscopy from the Spitzer Data Fusion to provide the most accurate determination to date of the local (0.02<z<0.5) Far-Infrared Luminosity and Star Formation Rate Function. We present and compare our results with model predictions as well as other multi-wavelength estimates of the local star formation rate density.

scholarly journals Serendipitous discovery of an “ALMA-only” galaxy at 5 < z < 6 in an ALMA 3-mm survey

2019 ◽  
Vol 15 (S352) ◽  
pp. 194-198
Author(s):  
Christina C. Williams
Keyword(s):  
Star Formation ◽  
Energy Distribution ◽  
Star Formation Rate ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Large Contribution ◽  
Massive Galaxies ◽  
Multi Wavelength

AbstractWe discuss the serendipitous discovery of a dusty high-redshift galaxy in a small (8 arcmin2) ALMA 3-mm survey Williams et al. (2019). The galaxy was previously unknown and is absent from existing multi-wavelength catalogs (“ALMA-only”). Using the ALMA position as prior, we perform forced deblended photometry to constrain its spectral energy distribution. The spectral energy distribution is well described by a massive (M* = 1010.8 M⊙) and highly obscured (AV ∼ 4) galaxy at redshift z = 5.5 ± 1.1 with star formation rate ∼ 300 M⊙yr−1. Our small survey area implies an uncertain but large contribution to the cosmic star formation rate density, similar to the contribution from all ultraviolet-selected galaxies combined at this redshift. This galaxy likely traces an abundant population of massive galaxies absent from current samples of infrared-selected or sub-millimeter galaxies, but with larger space densities, higher duty cycles, and significant contribution to the cosmic star-formation rate and stellar mass densities.

scholarly journals Scaling Relations between Gas and Star Formation in Nearby Galaxies

2010 ◽  
Vol 6 (S270) ◽  
pp. 327-334 ◽  
Author(s):  
Frank Bigiel ◽  
Adam Leroy ◽  
Fabian Walter
Keyword(s):  
Star Formation ◽  
Spatial Scales ◽  
Formation Rate ◽  
Star Forming ◽  
Multiple Regimes ◽  
Combining Data ◽  
Multi Wavelength ◽  
Nearby Galaxies ◽  
Physical Quantities ◽  
Individual Galaxy

AbstractHigh resolution, multi-wavelength maps of a sizeable set of nearby galaxies have made it possible to study how the surface densities of H i, H2 and star formation rate (ΣHI, ΣH2, ΣSFR) relate on scales of a few hundred parsecs. At these scales, individual galaxy disks are comfortably resolved, making it possible to assess gas-SFR relations with respect to environment within galaxies. ΣH2, traced by CO intensity, shows a strong correlation with ΣSFR and the ratio between these two quantities, the molecular gas depletion time, appears to be constant at about 2 Gyr in large spiral galaxies. Within the star-forming disks of galaxies, ΣSFR shows almost no correlation with ΣHI. In the outer parts of galaxies, however, ΣSFR does scale with ΣHI, though with large scatter. Combining data from these different environments yields a distribution with multiple regimes in Σgas – ΣSFR space. If the underlying assumptions to convert observables to physical quantities are matched, even combined datasets based on different SFR tracers, methodologies and spatial scales occupy a well define locus in Σgas – ΣSFR space.

scholarly journals Multi-wavelength de-blended Herschel view of the statistical properties of dusty star-forming galaxies across cosmic time

2019 ◽  
Vol 624 ◽  
pp. A98 ◽  
Author(s):  
L. Wang ◽  
W. J. Pearson ◽  
W. Cowley ◽  
J. W. Trayford ◽  
M. Béthermin ◽  
...  
Keyword(s):  
Star Formation ◽  
Dynamic Range ◽  
Transition Period ◽  
Formation Rate ◽  
Cosmic Time ◽  
Far Infrared ◽  
Statistical Properties ◽  
Star Forming ◽  
Multi Wavelength ◽  
Number Counts

Aims. We study the statistical properties of dusty star-forming galaxies across cosmic time, such as their number counts, luminosity functions (LF), and the dust-obscured star formation rate density (SFRD). Methods. We used the most recent de-blended Herschel catalogue in the COSMOS field to measure the number counts and LFs at far-infrared (FIR) and sub-millimetre (sub-mm) wavelengths. The de-blended catalogue was generated by combining the Bayesian source extraction tool XID+ and an informative prior derived from the associated deep multi-wavelength photometric data. Results. Through our de-confusion technique and based on the deep multi-wavelength photometric information, we are able to achieve more accurate measurements while at the same time probing roughly ten times below the Herschel confusion limit. Our number counts at 250 μm agree well with previous Herschel studies. However, our counts at 350 and 500 μm are below previous Herschel results because previous Herschel studies suffered from source confusion and blending issues. Our number counts at 450 and 870 μm show excellent agreement with previous determinations derived from single-dish and interferometric observations. Our measurements of the LF at 250 μm and the total IR LF agree well with previous results in the overlapping redshift and luminosity range. The increased dynamic range of our measurements allows us to better measure the faint-end of the LF and measure the dust-obscured SFRD out to z ∼ 6. We find that the fraction of obscured star formation activity is at its highest (>80%) around z ∼ 1. We do not find a shift of balance between z ∼ 3 and z ∼ 4 in the SFRD from being dominated by unobscured star formation at higher redshift to obscured star formation at lower redshift. However, we do find 3 <  z <  4 to be an interesting transition period as the portion of the total SFRD that is obscured by dust is significantly lower at higher redshifts.

scholarly journals Barred Extreme IRAS Galaxies

1996 ◽  
Vol 157 ◽  
pp. 256-258
Author(s):  
Wim van Driel ◽  
Bert van den Broek
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Formation Rate ◽  
Far Infrared ◽  
Radio Continuum ◽  
Massive Star Formation ◽  
Barred Galaxies ◽  
Interacting Systems ◽  
Isolated Systems ◽  
Infrared Brightness

AbstractWe studied a statistically complete sample of 57 southern socalled extreme IRAS galaxies, i.e., objects with a high far-infrared/blue luminosity ratio, LFIR/LB>3, using optical (imaging and spectra), radio continuum, and CO(1–0) line observations. The sample can be divided into three distinct categories: dwarfs (20%), barred spirals (35%), and interacting systems (35%). The barred galaxies are generally morphologically undisturbed, isolated systems, with average star formation rates (4 M⊙ yr–1) and efficiencies (LFIR/MH2 = 16 L⊙/M⊙) for galaxies in our sample. An enhanced massive star formation rate is the cause of the infrared brightness in 93% of all galaxies in the sample. The nuclear region is the most important star formation locus, generally unresolved at 1" resolution, i.e., less than 0.2-0.6 kpc size (H0=75 km s–1 Mpc–1), though 2 kpc size in three cases. In about two-thirds of the extreme IRAS SB’s, fainter, diffuse (2.5-10 kpc size) massive star formation is seen in the bar as well.

Reconstruction of Star Formation and AGNs Activities in Galaxies Classified with the Balmer Break, 1.6 μm Bump and PAH Features up to z ≃2

2010 ◽  
Vol 6 (S277) ◽  
pp. 182-185
Author(s):  
Hitoshi Hanami ◽  
Tsuyoshi Ishigaki ◽  
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Formation Rate ◽  
Massive Galaxies ◽  
Star Forming ◽  
Luminous Infrared Galaxies ◽  
The North ◽  
Deep Survey ◽  
Multi Wavelength ◽  
Dusty Torus

AbstractWe have studied the star-forming and AGN activity of massive galaxies in the redshift range z = 0.4−2, which are detected in a deep survey field using the AKARI and Subaru telescopes toward the North Ecliptic Pole (NEP). The multi-wavelength survey allows us to select Mid-InfraRed (MIR) bright populations as Luminous InfraRed Galaxies (LIRGs) with L(IR) ≃ 1010–11 L⊙, which can be also sub-classified into Balmer Break Galaxies (BBGs) and Infra-Red (IR) Bump Galaxies (IRBGs). AKARI/IRC multiband photometry can distinguish their star-forming/AGN activity for LIRGs with/without the Polycyclic-Aromatic Hydrocarbon (PAH) emission bands at 6.2, 7.7 and 11.3 μm, and estimate the Star Formation Rate (SFR) from their total emitting InfraRed (IR) luminosities for star-formings and the emissions from dusty torus for AGNs. The results are summarised as below: 1) The rest-frame 7.7 μm luminosity is still a good tracer of the total IR (tIR) luminosity, as the PAH emission dominates for star-forming galaxies even up to z ≃ 2, 2) Rest-frame 5μm Luminosities may trace emissions from dusty torus of AGN in the LIRGs, 3) SFR of Starburst-AGN LIRGs (s/a-LIRGs) tends to quench at z < 0.8 more rapidly than that of Starburst dominated LIRGs (sb-LIRGs), 4) Intrinsic Stellar populations in the s/a-LIRGs show redder colours than those in the sb-LIRGs. These results suggest that Super Massive Black Holes (SMBH) could already have grown to ≃ 3 × 108M⊙ in the agn-LIRGs, with ≃ 1011L⊙ at z > 1.2, and the growth of SMBH tends to follow the star-forming activities around z = 1–2.

scholarly journals Secular evolution in galaxies

2006 ◽  
Vol 2 (S235) ◽  
pp. 19-23 ◽  
Author(s):  
F. Combes
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Significant Role ◽  
High Frequency ◽  
Central Star ◽  
Barred Galaxies ◽  
Secular Evolution ◽  
Gas Accretion ◽  
Bar Formation

AbstractNew observations in favour of a significant role of secular evolution are reviewed: central star formation boosted in pseudo-bulge barred galaxies, relations between bulge and disk, evidence for rejuvenated bulges. Numerical simulations have shown that secular evolution can occur through a cycle of bar formation and destruction, in which the gas plays a major role. Since bars are weakened or destroyed in gaseous disks, the high frequency of bars observed today requires external cold gas accretion, to replenish the disk and allow a new bar formation. The rate of gas accretion from external filaments is compatible with what is observed in cosmological simulations.

scholarly journals Spectroscopic Observations of Hundreds of Star Formation Regions in M33

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Xu Kong ◽  
Ning Hu ◽  
Fuzhen Cheng
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Formation Rate ◽  
Dust Extinction ◽  
Spectroscopic Observations ◽  
Metal Abundance ◽  
Multi Wavelength ◽  
Nearby Galaxies ◽  
Star Formation Regions

AbstractStar-formation regions in nearby galaxies provide an excellent laboratory to study star formation processes, evolution of massive stars and the properties of the surrounding interstellar medium. A wealth of information can be obtained from their spectral analysis of the emission lines and the stellar continuum. Considering these, we proposed a long-term project “Spectroscopic Observations of the Star Formation Regions in Nearby Galaxies”. The primary goal of this project is to observe spectroscopy of star formation regions in 20 nearby galaxies, with the NAOC 2.16 m telescope and the Hectospec/MMT multifiber spectrograph. With the spectra of a large sample of star formation regions, combining multi-wavelength data from UV to IR, we can investigate, understand and quantify the dust extinction, star formation rate, metal abundance, and the two-dimensional distributions of stellar population properties of nearby galaxies. It will be important for a better understanding of galaxy formation. Here we report on the observations, data reduction, and analysis of the spectra of ~ 400 star formation regions in M33, via multifiber spectroscopy with Hectospec at the MMT.

Sign in / Sign up

Export Citation Format

Share Document