MID-INFRARED SPECTRAL INDICATORS OF STAR FORMATION AND ACTIVE GALACTIC NUCLEUS ACTIVITY IN NORMAL GALAXIES

We present a new diagnostic tool based on mid-infrared spectra (5–16μm) for distinguishing the emission triggered by the active galactic nucleus (AGN) and by the star formation activity. We show that the AGN spectra, contrary to the starburst spectra, present an important continuum below 9μm and an absence of Unidentified Infrared Bands (UIBs).

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THE MID-INFRARED LUMINOSITY FUNCTION ATz< 0.3 FROM 5MUSES: UNDERSTANDING THE STAR FORMATION/ACTIVE GALACTIC NUCLEUS BALANCE FROM A SPECTROSCOPIC VIEW

The Astrophysical Journal ◽

10.1088/0004-637x/734/1/40 ◽

2011 ◽

Vol 734 (1) ◽

pp. 40 ◽

Cited By ~ 12

Author(s):

Yanling Wu ◽

Yong Shi ◽

George Helou ◽

Lee Armus ◽

Daniel A. Dale ◽

...

Keyword(s):

Star Formation ◽

Active Galactic Nucleus ◽

Luminosity Function ◽

Mid Infrared

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Mid-Infrared Spectral Assessment of Early-type Galaxies with Star Formation

Proceedings of the International Astronomical Union ◽

10.1017/s174392131102240x ◽

2010 ◽

Vol 6 (S277) ◽

pp. 30-33 ◽

Cited By ~ 1

Author(s):

Lerothodi L. Leeuw ◽

Jesse D. Bregman ◽

Jacqueline Davidson ◽

Pasquale Temi ◽

Stephen S. Im

Keyword(s):

Star Formation ◽

Ir Spectra ◽

Elliptical Galaxies ◽

Mid Infrared ◽

Stellar Component ◽

Infrared Spectral ◽

Polycyclic Aromatic ◽

Associated Species ◽

Morphological Merger ◽

First Time

AbstractMid-infrared (mid-IR) spectra from ~5 to 14 μm of five, nearby (< 70 Mpc) elliptical galaxies are presented that were observed with the Infrared Spectrograph on the Spitzer Space Telescope. The sample galaxies have a main stellar component that is typical for normal, passively evolving ellipticals; however, they are rich in cold gas and dust and have morphological-merger signatures from which a time order of the galaxies since the merger or accretion events can be estimated. The presented results are significant because (1) emission due to Polycyclic Aromatic Hydrocarbons (PAHs) and associated species is detected for the first time in these galaxies and (2) the detected mid-IR spectra are independently exploited as a probe of current or recent star-formation that, in this case, is assumed to be triggered by the merger. As shown in exemplary spectra of the early-age merger NGC 3656, the strength of the PAH emission is more centrally peaked in the earlier-age mergers, suggesting that the PAH data are indeed probing star-formation that is correlated with the time since the mergers and systematically depletes the centrally located gas, becoming weaker and more flatly distributed as the merger evolves.

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Unveiling the composition of historical plastics through non-invasive reflection FT-IR spectroscopy in the extended near- and mid-Infrared spectral range

Analytica Chimica Acta ◽

10.1016/j.aca.2021.338602 ◽

2021 ◽

pp. 338602

Author(s):

Francesca Rosi ◽

Costanza Miliani ◽

Peter Gardner ◽

Annalisa Chieli ◽

Aldo Romani ◽

...

Keyword(s):

Ir Spectroscopy ◽

Spectral Range ◽

Mid Infrared ◽

Non Invasive ◽

Infrared Spectral Range ◽

Infrared Spectral ◽

Ft Ir ◽

Ft Ir Spectroscopy

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Testing the link between mergers and AGN in the Arp 245 system

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001842 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 192-194

Author(s):

Elismar Lösch ◽

Daniel Ruschel-Dutra

Keyword(s):

Star Formation ◽

Active Galactic Nucleus ◽

Spherical Surface ◽

Galaxy Mergers ◽

Nuclear Activity ◽

Upper Limit ◽

Spherical Surfaces ◽

Galactic Centers ◽

Merger Event ◽

Major Merger

AbstractGalaxy mergers are known to drive an inflow of gas towards galactic centers, potentia- lly leading to both star formation and nuclear activity. In this work we aim to study how a major merger event in the ARP 245 system is linked with the triggering of an active galactic nucleus (AGN) in the NGC galaxy 2992. We employed three galaxy collision numerical simulations and calculated the inflow of gas through four different concentric spherical surfaces around the galactic centers, estimating an upper limit for the luminosity of an AGN being fed the amount of gas crossing the innermost spherical surface. We found that these simulations predict reasonable gas inflow rates when compared with the observed AGN luminosity in NGC 2992.

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Connecting the Interstellar Gas and Dust Properties in Distant Galaxies Using Quasar Absorption Systems

Proceedings of the International Astronomical Union ◽

10.1017/s174392131600764x ◽

2015 ◽

Vol 11 (S315) ◽

Author(s):

Monique C. Aller ◽

Varsha P. Kulkarni ◽

Donald G. York ◽

Daniel E. Welty ◽

Giovanni Vladilo ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Absorption Feature ◽

Dust Grains ◽

Interstellar Gas ◽

Chemical Enrichment ◽

Normal Galaxies ◽

History Of ◽

Dust Grain ◽

Grain Properties

AbstractGas and dust grains are fundamental components of the interstellar medium and significantly impact many of the physical processes driving galaxy evolution, such as star-formation, and the heating, cooling, and ionization of the interstellar material. Quasar absorption systems (QASs), which trace intervening galaxies along the sightlines to luminous quasars, provide a valuable tool to directly study the properties of the interstellar gas and dust in distant, normal galaxies. We have established the presence of silicate dust grains in at least some gas-rich QASs, and find that they exist at higher optical depths than expected for diffuse gas in the Milky Way. Differences in the absorption feature shapes additionally suggest variations in the silicate dust grain properties, such as in the level of grain crystallinity, from system-to-system. We present results from a study of the gas and dust properties of QASs with adequate archival IR data to probe the silicate dust grain properties. We discuss our measurements of the strengths of the 10 and 18 μm silicate dust absorption features in the QASs, and constraints on the grain properties (e.g., composition, shape, crystallinity) based on fitted silicate profile templates. We investigate correlations between silicate dust abundance, reddening, and gas metallicity, which will yield valuable insights into the history of star formation and chemical enrichment in galaxies.

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