scholarly journals A Spitzer study of interacting luminous and ultra-luminous infrared galaxies

2011 ◽  
Vol 7 (S284) ◽  
pp. 202-204
Author(s):  
João Rodrigo S. Leão ◽  
Claus Leitherer
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Interacting Galaxies ◽  
Optical Data ◽  
Relative Importance ◽  
Infrared Galaxies ◽  
Nuclear Activity ◽  
Space Telescope ◽  
Luminous Infrared Galaxies ◽  
Interacting Systems

AbstractWe conducted a Spitzer Space Telescope survey of 28 Luminous (11 < log (LIR/L⊙) < 12, LIRGs) and Ultra-Luminous Infrared Galaxies (log (LIR/L⊙) > 12, ULIRGs). Many of these galaxies are found in pairs or associations and are powered by either nuclear activity or star-formation (Sanders & Mirabel 1996). Our main goal is to understand the relative importance of starbursts and AGNs in interacting systems. Is the frequency of AGN and starbursts in these interacting galaxies related to their luminosities? What is the importance of the merger stage and the frequency of AGNs? We present our conclusions and diagnostic diagrams based in the observed near infrared lines and compare to studies based solely in optical data.

scholarly journals Star formation and nuclear activity in luminous infrared galaxies: an infrared through radio review

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Miguel Pérez-Torres ◽  
Seppo Mattila ◽  
Almudena Alonso-Herrero ◽  
Susanne Aalto ◽  
Andreas Efstathiou
Keyword(s):  
Star Formation ◽  
Infrared Galaxies ◽  
Nuclear Activity ◽  
Luminous Infrared Galaxies

scholarly journals IRS spectroscopic studies of ULIRGs at z ~ 2

2012 ◽  
Vol 8 (S295) ◽  
pp. 82-85
Author(s):  
Guanwen Fang ◽  
Xu Kong ◽  
Jia-Sheng Huang ◽  
Zhongyang Ma
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Formation Rate ◽  
Spectroscopic Studies ◽  
Formation Processes ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies ◽  
Very High

AbstractWe present a result of IRS spectroscopy of 14 Ultra-Luminous Infrared Galaxies (ULIRGs) in the Extended Groth Strip region. These galaxies are massive and have very high star formation rate. Four objects of this sample are detected in the HST/WFC3 near-infrared imaging. They show very diversified rest-frame optical morphologies, including string-like, extended/diffused, and even spiral with a possible bulge, implying different formation processes for these galaxies. We also search for signatures of active galactic nucleus (AGN) in our sample in the X-ray, mid-infrared and radio bands. This sample is dominated by objects with intensive star formation, only 14–29% of them have AGN activities.

scholarly journals Buried AGNs and Starbursts in Luminous and Ultra-Luminous Infrared Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 116-116
Author(s):  
João Rodrigo S. Leão ◽  
Patrícia Hepp ◽  
Claus Leitherer
Keyword(s):  
Strong Evidence ◽  
Infrared Emission ◽  
Emission Lines ◽  
Infrared Galaxies ◽  
Spitzer Space Telescope ◽  
Nuclear Activity ◽  
Space Telescope ◽  
Luminous Infrared Galaxies ◽  
First Results

AbstractWe present the first results of a Spitzer Space Telescope survey of 28 LIRGs and ULIRGs. We used infrared emission lines to separeate AGN and starburst powered systems. We find strong evidence that the incidence of nuclear activity increases with infrared luminosity.

scholarly journals Molecules as tracers of galaxy evolution

2012 ◽  
Vol 8 (S292) ◽  
pp. 199-208 ◽  
Author(s):  
Susanne Aalto
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
High Resolution ◽  
Galaxy Evolution ◽  
Large Scale ◽  
Short Review ◽  
Stimulated Emission ◽  
Molecular Gas ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies

AbstractStudying the molecular phase of the interstellar medium in galaxies is fundamental for the understanding of the onset and evolution of star formation and the growth of supermassive black holes. We can use molecules as observational tools exploiting them as tracers of chemical, physical and dynamical conditions. In this short review, key molecules (e.g. HCN, HCO+, HNC, HC3N, CN, H3O+) in identifying the nature of buried activity and its evolution are discussed including some standard astrochemical scenarios. Furthermore, we can use IR excited molecular emission to probe the very inner regions of luminous infrared galaxies (LIRGs) allowing us to get past the optically thick dust barrier of the compact obscured nuclei, e.g. in the dusty LIRG NGC4418. High resolution studies are often necessary to separate effects of excitation and radiative transport from those of chemistry - one example is absorption and effects of stimulated emission in the ULIRG Arp220. Finally, molecular gas in large scale galactic outflows is briefly discussed.

scholarly journals Recent Star Formation in Very Luminous Infrared Galaxies

2001 ◽  
pp. 171-176 ◽  
Author(s):  
Alessandro Bressan ◽  
Bianca Poggianti ◽  
Alberto Franceschini
Keyword(s):  
Star Formation ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies

scholarly journals Luminous IR Galaxies in a Merger Sequence: Bima Co Imaging

1999 ◽  
Vol 186 ◽  
pp. 227-230
Author(s):  
Y. Gao ◽  
R.A. Gruendl ◽  
C.-Y. Hwang ◽  
K.Y. Lo
Keyword(s):  
Star Formation ◽  
Power Output ◽  
Infrared Galaxies ◽  
Physical Processes ◽  
Luminous Infrared Galaxies ◽  
Bolometric Luminosity

The power output in luminous infrared galaxies (LIGs, LIR ≳ 1011L⊙, H0 = 75 kms−1 Mpc−1) can approach the bolometric luminosity of quasars and can be provided by either starbursts or dust-enshouded QSOs, or both. Most LIGs appear to comprise of mergers of gas-rich galaxies. So, intense bursts of star formation apparently result from interaction and merging of galaxies, but the exact physical processes involved in collecting the large amount of gas involved and in initiating the starbursts are not well understood.

scholarly journals Star-formation histories of local luminous infrared galaxies

2015 ◽  
Vol 577 ◽  
pp. A78 ◽  
Author(s):  
Miguel Pereira-Santaella ◽  
Almudena Alonso-Herrero ◽  
Luis Colina ◽  
Daniel Miralles-Caballero ◽  
Pablo G. Pérez-González ◽  
...  
Keyword(s):  
Star Formation ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies ◽  
Star Formation Histories

scholarly journals Evolution of Very Luminous Infrared Galaxies

1999 ◽  
Vol 186 ◽  
pp. 364-364
Author(s):  
H. Wu ◽  
Z.L. Zou ◽  
X.Y. Xia ◽  
Z. G. Deng
Keyword(s):  
Spectral Classification ◽  
Dynamical Friction ◽  
Infrared Galaxies ◽  
Nuclear Activity ◽  
Classification Schemes ◽  
Luminous Infrared Galaxies ◽  
Luminous Galaxies ◽  
Class 1 ◽  
Nuclear Separation ◽  
Last Stage

We have completed spectroscopic observations (Wu et al. 1997a) of a sample of 73 very luminous infrared galaxies (log(LIR/L⊙) ≥ 11.5;H0 = 50 km s−1 Mpc−1) from the 2-Jy catalogue (Strauss et al. 1992) using the 2.16m telescope at the Beijing Astronomical Observatory. Spectral and interacting classifications are performed for the sample (Wu et al. 1997b). These statistical results provide strong evidence for the idea that interactions trigger nuclear activity and enhance the infrared luminosity. With the decrease of nuclear separation, relative velocity and specific angular momentum decrease rapidly, while on the contrary, both infrared luminosity and Hα equivalent width increase. Dynamical friction plays an important role even when two galaxies have large separation. This provides a favorable condition for strong star formation. We construct a simple merger sequence, from interaction class 1 to 4, to class 5 and 6 and then to the class 0 regarded as being in the stage of advanced merger. Along this sequence, spectral types change from HII-like to AGN-like. Considering the strong correlation of very luminous infrared galaxies in spectral classification schemes, it is reliable that infrared luminous galaxies evolve from HII-like galaxies to AGN-like galaxies. The different properties of infrared luminous Seyfert 1s and optically selected Seyfert 1s suggest that infrared luminous galaxies could evolve into optical Seyfert 1s in the last stage.

scholarly journals Multi-Color Imaging of Selected Southern Interacting Galaxies

1990 ◽  
Vol 124 ◽  
pp. 55-58
Author(s):  
Eric P. Smith ◽  
Paul Hintzen
Keyword(s):  
Broad Band ◽  
Radio Galaxies ◽  
Spectroscopic Studies ◽  
Interacting Galaxies ◽  
Similar Data ◽  
Galaxy Mergers ◽  
Powerful Radio ◽  
Nuclear Activity ◽  
Interacting Systems

We present preliminary results from a study of selected Arp-Madore Southern Hemisphere peculiar galaxies. Broadband CCD images (BVRI) of a subset of these galaxies allow us to study each galaxy’s optical morphology, color, and (in a crude manner) degree of nuclear activity, and to compare them with similar data we possess on other active galaxies. Many of these galaxies have optical morphologies closely resembling those of powerful radio galaxies (Smith and Heckman 1989), yet their radio emission is unremarkable. Accurate positions for subsequent spectroscopic studies have been determined along with broad band photometry and morphology studies. Detailed observations of these comparatively bright, low-redshift, well-resolved interacting systems should aid our understanding of the role interactions play in triggering galaxy activity. This work is the initial effort in a long term project to study the role played by the dynamics of the interaction in the production and manifestations of activity in galaxies, and the frequency of galaxy mergers.

Massive star formation in local luminous infrared galaxies

2009 ◽  
Vol 324 (2-4) ◽  
pp. 333-336
Author(s):  
Almudena Alonso-Herrero ◽  
Tanio Díaz-Santos ◽  
Macarena García-Marín ◽  
Luis Colina ◽  
Santiago Arribas ◽  
...  
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Infrared Galaxies ◽  
Massive Star Formation ◽  
Luminous Infrared Galaxies
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