Prof. Dimitra Rigopoulou: Publications

The nature of ISOCAM galaxies in the Hubble Deep Field South

SPRINGER PROC PHYS 88 (2001) 255-260

Authors:

D Rigopoulou, A Franceschini, R Genzel

Abstract:

The various deep ISOCAM surveys revealed a new class of infrared luminous galaxies which are characterized by a high rate of evolution and are found at redshifts of zsimilar to1. Here we report results of our near-infrared VLT-ISAAC spectroscopic survey aimed at characterising the nature of these sources. We find that the rest-frame R-band spectra resemble those of powerful dust enshrouded starbursts. More recent detailed studies revealed that some of these systems are in fact extremely massive galaxies.

The European Large Area ISO Survey IV: the preliminary 90 micron luminosity function

(2000)

Authors:

S Serjeant, A Efstathiou, S Oliver, C Surace, P Heraudeau, M Linden-Vornle, C Gruppioni, F La Franca, D Rigopoulou, T Morel, H Crockett, T Sumner, M Rowan-Robinson, M Graham

The European Large Area ISO Survey III: 90micron extragalactic source counts

(2000)

Authors:

A Efstathiou, S Oliver, M Rowan-Robinson, C Surace, T Sumner, P Heraudeau, MJD Linden-Vornle, D Rigopoulou, S Serjeant, RG Mann, CJ Cesarsky, L Danese, A Franceschini, R Genzel, A Lawrence, D Lemke, RG McMahon, G Miley, J-L Puget, B Rocca-Volmerange

VLT-ISAAC near-IR Spectroscopy of ISO selected Hubble Deep Field South Galaxies

(2000)

Authors:

D Rigopoulou, A Franceschini, H Aussel, R Genzel, P van der Werf, CJ Cesarsky, M Dennefeld, S Oliver, M Rowan-Robinson, RG Mann, I Perez-Fournon, B Rocca-Volmerange

Galaxies: The short wavelength view

ESA SP PUBL 456 (2000) 233-238

Authors:

D Lutz, R Genzel, E Sturm, D Rigopoulou, D Tran, AFM Moorwood, HWW Spoon, N Forster-Schreiber, M Thornley, T Alexander, A Sternberg

Abstract:

With the advent of ISO, mid-infrared spectroscopy has become sensitive enough for detailed analyses of sizeable samples of galaxies. Mid-infrared aromatic emission features are detected strong and ubiquitously in star forming galaxies. They are absent close to an active galactic nucleus but can be strong on larger scales of the AGN host, in particular if there is intense circumnuclear star formation. Through their nebular emission, hot star populations can be studied in dusty environments like starburst galaxies. Starbursts seem to be normal in their hot star initial mass function but short lived due to strong negative feedback. The rich fine structure and coronal line spectrum of active galaxies can be used to reconstruct the otherwise unobservable extreme ultraviolet emission of the AGN. We find evidence for 'big blue bump' emission from the accretion disk but also for neutral absorbers located inside the narrow line region. Mid-infrared emission lines and continuum features provide new diagnostics to discriminate between starburst and AGN activity in obscured galaxies. Using these tools, we find that most ultraluminous infrared galaxies are predominantly starburst powered. Our total sample of about 75 ULIRGs allows to search for trends within the class of ULIRGs: The fraction of AGNs increases with luminosity above similar to 3 x 10(12)L(circle dot) but there is no obvious trend for ULIRGs to be more AGN-like with more advanced merger phase.

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