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
  • I ricordi personali di chi ha conosciuto e lavorato con il premio Nobel 2002 per la Fisica e ha voluto testimoniarlo qui, sulle pagine di Media Inaf: Salvatore Sciortino, Sperello di Serego Alighieri, Gianni Zamorani, Piero Rosati, Stefano Borgani, Roberto Gilli, Maurizio Paolillo e Paolo Tozzi

  • Arriva in Italia il 19 dicembre la serie evento creata dallo showrunner di ”House of Cards”, Beau Willimon. Storia del primo volo umano con destinazione Pianeta rosso. I primi due episodi in anteprima gratuita martedì 18 dicembre in 30 sale cinema

  • A mezzo secolo dalla pubblicazione su “Nature” dell’articolo che descriveva la scoperta della prima pulsar, il “Libro dell’Anno” Treccani ospita nella sezione “Personaggi” un articolo di Patrizia Caraveo dedicato a Jocelyn Bell Burnell. Ve lo riproponiamo con il consenso dell’autrice

  • Analizzando campioni di rocce prelevati nel sistema di grotte noto come Imawarì Yeuta, in Venezuela, un gruppo multidisciplinare di ricercatori ha dimostrato che l’attività metabolica di comunità microbiche complesse è coinvolta nella formazione di particolari depositi di silice opalina. Depositi simili sono stati osservati anche su Marte dal rover Spirit della Nasa: dal Venezuela a Marte, il passo potrebbe essere più breve del previsto. I risultati sono stati pubblicati su Scientific Reports

  • Osservati i segni di una neonata onda d’urto di prua – bow shock in inglese – generata dal vento solare attorno alla cometa 67P: è la prima volta che il fenomeno viene colto nella fase di formazione. I risultati dello studio, condotto rianalizzando i dati della suite di strumenti Rosetta Plasma Consortium, sono pubblicati su Astronomy & Astrophysics

  • Dal 6 all'11 dicembre la sonda Mars Reconnaissance Orbiter ha fotografato il lander, il suo scudo termico e il paracadute che ora si trovano nella regione sabbiosa di Elysium Planitia

Edu INAF - Risorse e iniziative per la scuola e la società dell'INAF

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