scholarly journals Star Formation in a Magnitude Limited Sample of Interacting Galaxies

1996 ◽  
Vol 171 ◽  
pp. 344-344
Author(s):  
Nils Bergvall ◽  
Eija Laurikainen ◽  
Susanne Aalto ◽  
Lennart Johansson
Keyword(s):  
Star Formation ◽  
Control Sample ◽  
Central Area ◽  
Interacting Galaxies ◽  
Moderate Increase ◽  
Limited Sample ◽  
Merging Galaxies ◽  
Near Ir ◽  
Isolated Galaxies ◽  
Star Formation Activity

We report on optical/near-IR spectroscopy and photometry of a magnitude limited sample of interacting pairs and merging galaxies and a control sample of apparently isolated galaxies (1,2). All observations were carried out at ESO, La Silla. When compared to the control sample, the interacting galaxies show only a moderate increase of star formation activity, in the central area typically a factor 2-3. Starburst activity seems to be very rare. Ongoing CO observations (Aalto, Horellou, Booth, Wiklind, Bergvall) indicate that these objects are not particularly rich in molecular gas. The interacting/merging galaxies have relatively high optical luminosities and high FIR luminosities and temperatures but these parameters are not correlated with other star formation signatures. We conclude that the interacting and merging galaxies in this sample, from the global star formation aspect, do not differ dramatically from scaled up versions of normal, isolated galaxies. This could suggest that many of the most lumino components in interacting pairs could originate from multiple ‘quiet’ mergers.

scholarly journals A Reference Sample: ISM of the Most Isolated Galaxies

2004 ◽  
Vol 217 ◽  
pp. 220-221
Author(s):  
L. Verdes-Montenegro ◽  
J. Sulentic ◽  
D. Espada ◽  
S. Leon ◽  
U. Lisenfeld ◽  
...  
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Galaxy Evolution ◽  
Reference Sample ◽  
Control Sample ◽  
Evolution Of Galaxies ◽  
Isolated Galaxies ◽  
Internal Evolution

We are constructing the first complete unbiased control sample of the most isolated galaxies of the northern sky to serve as a template in the study of star formation and galaxy evolution in denser environments. Our goal is to compare and quantify the properties of different phases of the interstellar medium in this sample, as well as the level of star formation, both relevant parameters in the internal evolution of galaxies and strongly conditioned by the environment. To achieve this goal we are building a multiwavelength database for this sample to compare and quantify the properties of different phases of the ISM.

scholarly journals Satellites and central galaxies in SDSS: the influence of interactions on their properties

2020 ◽  
Vol 501 (1) ◽  
pp. 1046-1058
Author(s):  
Valeria Mesa ◽  
Sol Alonso ◽  
Georgina Coldwell ◽  
Diego García Lambas ◽  
J L Nilo Castellon
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Control Sample ◽  
Stellar Populations ◽  
Control Sets ◽  
Central Galaxy ◽  
Star Formation Activity ◽  
Projected Distance

ABSTRACT We use SDSS-DR14 to construct a sample of galaxy systems consisting of a central object and two satellites. We adopt projected distance and radial velocity difference criteria and impose an isolation criterion to avoid membership in larger structures. We also classify the interaction between the members of each system through a visual inspection of galaxy images, finding ${\sim}80{{\ \rm per\ cent}}$ of the systems lack evidence of interactions whilst the remaining ${\sim}20{{\ \rm per\ cent}}$ involve some kind of interaction, as inferred from their observed distorted morphology. We have considered separately, samples of satellites and central galaxies, and each of these samples were tested against suitable control sets to analyse the results. We find that central galaxies showing signs of interactions present evidence of enhanced star formation activity and younger stellar populations. As a counterpart, satellite samples show these galaxies presenting older stellar populations with a lower star formation rate than the control sample. The observed trends correlate with the stellar mass content of the galaxies and with the projected distance between the members involved in the interaction. The most massive systems are less affected since they show no star formation excess, possibly due to their more evolved stage and less gas available to form new stars. Our results suggest that it is arguably a transfer of material during interactions, with satellites acting as donors to the central galaxy. As a consequence of the interactions, satellite stellar population ages rapidly and new bursts of star formation may frequently occur in the central galaxy.

Kinematic asymmetry of galaxy pairs

2019 ◽  
Vol 14 (S353) ◽  
pp. 262-263
Author(s):  
Shuai Feng ◽  
Shi-Yin Shen ◽  
Fang-Ting Yuan
Keyword(s):  
Star Formation ◽  
Velocity Field ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Control Sample ◽  
Interacting Galaxies ◽  
Ionized Gas ◽  
Galaxy Interaction ◽  
The Galaxy

AbstractThe interaction between galaxies is believed to be the main origin of the peculiarities of galaxies. It can disturb not only the morphology but also the kinematics of galaxies. These disturbed and asymmetric features are the indicators of galaxy interaction. We study the velocity field of ionized gas in galaxy pairs based on MaNGA survey. Using the kinemetry package, we fit the velocity field and quantify the degree of kinematic asymmetry. We find that the fraction of high kinematic asymmetry is much higher for galaxy pairs with dp⩽30h−1kpc. Moreover, compared to a control sample of single galaxies, we find that the star formation rate is enhanced in paired galaxies with high kinematic asymmetry. For paired galaxies with low kinematic asymmetry, no significant SFR enhancement has been found. The galaxy pairs with high kinematic asymmetry are more likely to be real interacting galaxies rather than projected pairs.

scholarly journals Interacting galaxies in the nearby Universe: only moderate increase of star formation

2015 ◽  
Vol 454 (2) ◽  
pp. 1742-1750 ◽  
Author(s):  
Johan H. Knapen ◽  
Mauricio Cisternas ◽  
Miguel Querejeta
Keyword(s):  
Star Formation ◽  
Interacting Galaxies ◽  
Moderate Increase

scholarly journals Gas Flows in Galaxies: the Relative Importance of Mergers and Bars.

2010 ◽  
Vol 6 (S277) ◽  
pp. 178-181
Author(s):  
Sara L. Ellison ◽  
David R. Patton ◽  
Preethi Nair ◽  
Luc Simard ◽  
J. Trevor Mendel ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Formation Rate ◽  
Control Sample ◽  
Central Star ◽  
Sloan Digital Sky Survey ◽  
Galaxy Interactions ◽  
Barred Galaxies ◽  
Isolated Galaxies ◽  
Stellar Masses

AbstractGalaxy-galaxy interactions and large scale galaxy bars are usually considered as the two main mechanisms for driving gas to the centres of galaxies. By using large samples of galaxy pairs and visually classified bars from the Sloan Digital Sky Survey (SDSS), we compare the relative efficiency of gas inflows from these two processes. We use two indicators of gas inflow: star formation rate (SFR) and gas phase metallicity, which are both measured relative to control samples. Whereas the metallicity of galaxy pairs is suppressed relative to its control sample of isolated galaxies, galaxies with bars are metal-rich for their stellar mass by 0.06 dex over all stellar masses. The SFRs of both the close galaxy pairs and the barred galaxies are enhanced by ~60%, but in the bars the enhancement is only seen at stellar masses M∗ > 1010 M⊙. Taking into account the relative frequency of bars and pairs, we estimate that at least three times more central star formation is triggered by bars than by interactions.

scholarly journals Nuclear starburst activity induced by elongated bulges in spiral galaxies

2018 ◽  
Vol 479 (1) ◽  
pp. 562-569 ◽  
Author(s):  
Eunbin Kim ◽  
Sungsoo S Kim ◽  
Yun-Young Choi ◽  
Gwang-Ho Lee ◽  
Richard de Grijs ◽  
...  
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Sloan Digital Sky Survey ◽  
Two Dimensional ◽  
Limited Sample ◽  
Barred Galaxies ◽  
Star Formation Activity ◽  
Sky Survey ◽  
Data Release ◽  
Environmental Dependence

ABSTRACT We study the effects of bulge elongation on the star formation activity in the centres of spiral galaxies using the data from the Sloan Digital Sky Survey Data Release 7. We construct a volume-limited sample of face-on spiral galaxies with Mr < −19.5 mag at 0.02 ≤ $z$ < 0.055 by excluding barred galaxies, where the aperture of the SDSS spectroscopic fibre covers the bulges of the galaxies. We adopt the ellipticity of bulges measured by Simard et al., who performed two-dimensional bulge + disc decompositions using the SDSS images of galaxies, and identify nuclear starbursts using the fibre specific star formation rates derived from the SDSS spectra. We find a statistically significant correlation between bulge elongation and nuclear starbursts in the sense that the fraction of nuclear starbursts increases with bulge elongation. This correlation is more prominent for fainter and redder galaxies, which exhibit higher ratios of elongated bulges. We find no significant environmental dependence of the correlation between bulge elongation and nuclear starbursts. These results suggest that non-axisymmetric bulges can efficiently feed the gas into the centre of galaxies to trigger nuclear starburst activity.

scholarly journals Inverse stellar population age gradients of post-starburst galaxies at z = 0.8 with LEGA-C

2020 ◽  
Vol 497 (1) ◽  
pp. 389-404 ◽  
Author(s):  
Francesco D’Eugenio ◽  
Arjen van der Wel ◽  
Po-Feng Wu (吳柏锋) ◽  
Tania M Barone ◽  
Josha van Houdt ◽  
...  
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Control Sample ◽  
Mass Range ◽  
Spatially Resolved ◽  
Star Formation Activity ◽  
Multiple Paths ◽  
High Fraction ◽  
Spatially Resolved Spectroscopy ◽  
Inside Out

ABSTRACT We use deep, spatially resolved spectroscopy from the Large Early Galaxy Astrophysics Census Survey to study radial variations in the stellar population of 17 spectroscopically selected post-starburst (PSB) galaxies. We use spectral fitting to measure two Lick indices, H δA and Fe 4383 , and find that, on average, PSB galaxies have radially decreasing H δA and increasing Fe 4383  profiles. In contrast, a control sample of quiescent, non-PSB galaxies in the same mass range shows outwardly increasing H δA and decreasing Fe 4383 . The observed gradients are weak (≈−0.2 Å/Re), mainly due to seeing convolution. A two-SSP (simple stellar population) model suggests that intrinsic gradients are as strong as observed in local PSB galaxies (≈−0.8 Å/Re). We interpret these results in terms of inside-out growth (for the bulk of the quiescent population) versus star formation occurring last in the centre (for PSB galaxies). At z ≈ 0.8, central starbursts are often the result of gas-rich mergers, as evidenced by the high fraction of PSB galaxies with disturbed morphologies and tidal features (40 per cent). Our results provide additional evidence for multiple paths to quiescence: a standard path, associated with inside-out disc formation and with gradually decreasing star formation activity, without fundamental structural transformation, and a fast path, associated with centrally concentrated starbursts, leaving an inverse age gradient and smaller half-light radius.

scholarly journals The HI Content of Non-Isolated Galaxies

1990 ◽  
Vol 124 ◽  
pp. 175-182
Author(s):  
Anatoli V. Zasov
Keyword(s):  
Star Formation ◽  
Time Scale ◽  
Star Formation Rate ◽  
Massive Stars ◽  
Formation Rate ◽  
Interacting Galaxies ◽  
Gas Content ◽  
Disk Galaxies ◽  
Isolated Galaxies

It seems obvious that the evolution of star formation rate and hence of gas content in galaxies strongly depends on their environment. It reveals itself in particular in enhanced star formation or even in a strong burst of activity of massive stars often observed in an interacting galaxies. Nevertheless it should be noted that the time scale for the gas to be exhausted in these galaxies is unknown even approximately. To clarify a role of surroundings in the evolution of disk galaxies we should compare the HI content of isolated and non-isolated galaxies otherwise similar by their properties.

scholarly journals Triggering Star Formation by Galaxy-Galaxy Interactions

2004 ◽  
Vol 217 ◽  
pp. 434-435
Author(s):  
P.B. Tissera ◽  
M.S. Alonso ◽  
D.G. Lambas ◽  
G. Coldwell
Keyword(s):  
Star Formation ◽  
Physical Processes ◽  
Redshift Distribution ◽  
Galaxy Interactions ◽  
Tidal Interactions ◽  
Isolated Galaxies ◽  
Star Formation Activity

We analyzed the effects of having a close companion on the star formation activity of galaxies in the 8K galaxy pair catalog selected from the 2dFGRS. We found that, statistically, galaxies with rp < 25h−1 kpc and ΔV < 100km s−1 have enhanced star formation with respect to isolated galaxies with the same luminosity and redshift distribution. Our results suggest that the physical processes at work during tidal interactions can overcome the effects of environment, except in dense regions.

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