The High-Z Universe

Understanding the physics and tracing the cosmic history of the galaxy mass assembly is one of the main open questions of galaxy formation and evolution. Despite the tremendous progress in observational cosmology, the accuracy in the estimate of cosmological parameters and the successful convergence on the LambdaCDM cosmological model, the mechanisms leading to the birth and the evolution of galaxies are still poorly known.

The empirical approach adopted is the investigation of galaxy formation and evolution to search for and to study the populations of distant galaxies.
Samples selected in the optical bands allow to cull star-forming galaxies where the redshifted ultraviolet (UV) radiation is dominated by hot, massive and short-lived stars. However, optical samples are affected by severe biases due to the strong influence of dust extinction and to the wide range of shapes of the spectral energy distributions (SEDs) depending on the level of star formation activity and on the age of the galaxy.
At longer wavelengths, the above problems are alleviated, as the rest-frame near-infrared radiation is dominated by low mass, long-lived stars. Also, the shapes of the SEDs in such a spectral range are very similar for all galaxy types, and the effects of dust extinction become less severe.

In addition, the rest-frame near-IR luminosity is known to correlate with the galaxy mass. The above advantages make galaxy samples selected in the near- (e.g. K-band at 2.2mum) or, even better, in the mid-IR (e.g. 4-8mum, now possible with the Spitzer Space Telescope) more suitable than optical samples to investigate galaxy evolution and, particularly, the history of galaxy stellar mass assembly.

At OAPd we are deeply involved in many ongoing survey projects as GOODS, GMASS, COSMOS and others, aimed at mapping the galaxy populations as a function of redshift and environment. These projects are establishing the observational facts that theoretical modelling will try to reproduce, ensuring full multiwavelength coverage from X-rays to radio making use of all main observational facilities worldwide, both on the ground and in space. Moreover, data from previous IR mission, i.e., the ISO mission which also involved people from OAPd, are now reduced and published.
These observations allowed us to deep our knowledge on the IR and far-IR luminosity functions (LF), which have long been used to constrain galaxy formation models and to quantify star formation and evolution both in luminosity and in density. Thanks to our ISOCAM, optical/near-IR observations and spectroscopy we presented the 60 micron LF and the bi-variate 15 micron LF, one of the few determinations based on ISO data, of a sample of galaxies on which numerous study of galaxy evolution still rely. Despite the fact that our redshift range exceeds 0.3, and our 60micron LF extends up to log(L60)=12, does not show any evidence of evolution.

The high-z Universe -PAST STUDIES

News – MEDIA INAF

Il notiziario online dell'Istituto Nazionale di Astrofisica
  • Firmato un protocollo d'intesa tra Miur, Regione, Università di Sassari e Istituto nazionale di fisica nucleare per candidare il sito di Sos Enattos. Il dicastero di viale Trastevere interverrà con fondi statali per 17 milioni di euro. L’interferometro di terza generazione si aggiungerà ai già funzionanti Ligo e Virgo

  • Il presidente dell'Agenzia spaziale italiana Roberto Battiston visita il Sardinia Radio Telescope, dando corso alla Convenzione tra Inaf e Asi per l'utilizzo dell'antenna nel Deep Space Network della Nasa

  • Stelle di neutroni, nane bianche, stelle in formazione: tutte, raggiunte determinate condizioni, mostrano lo stesso comportamento, ovvero la capacità di espellere materia ad altissima velocità: un fenomeno noto con il nome di ”propeller”. A fornire prove di questa universalità è il lavoro di quattro ricercatori dell’Inaf

  • Un po’ come gemelli, le stelle di una galassia e il buco nero centrale sembrano crescere assieme, almeno per quanto riguarda la massa. Uno studio nippo-taiwanese con il radiotelescopio Alma ha però trovato una particolare galassia in cui questo meccanismo di feedback non avviene. Il commento di Michele Perna dell'Inaf

  • Utilizzando la telecamera ad infrarossi CanariCam installata sul Gran Telescopio Canarias, un gruppo di ricercatori ha realizzato una dettagliata mappa che rileva i campi magnetici dei gas e delle polveri che spiraleggiano attorno al buco nero supermassiccio al centro della nostro galassia

  • Sfruttando il lieve attrito della rarefatta atmosfera marziana, il Trace Gas Orbiter di ExoMars dell’Esa ha progressivamente abbassato la propria orbita attorno al pianeta, ed è ormai pronto per iniziare le operazioni scientifiche, in particolare la ricerca del metano

Go to top

We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of the site have already been set. To find out more about the cookies we use and how to delete them, see our privacy policy.

I accept cookies from this site.

EU Cookie Directive Module Information