Spitzer

The feedback processes linking quasar activity to galaxy stellar mass growth are not well understood. If star formation is closely causally linked to black hole accretion, one may expect star formation confined to nuclear regions rather than extended over several kpc scales. Since Polycyclic Aromatic Hydrocarbon (PAH) emission features are widely used as tracers of stellar formation, it is, therefore, possible to use PAH emission detected around QSOs to help resolve this question. PAH data from a sample of 63 QSOs procured from the Spitzer Space Telescope’s Infrared Spectrograph (IRS) is used, employing the Spectroscopic Modelling Analysis and Reduction Tool’s (SMART) Advanced Optimal (AdOpt) extraction routines. A composite spectrum was also produced to help determine the average conditions and compositions of star forming regions. It is found, from our high redshift (𝑧>1) sample of QSOs, there is a marginally significant extended star formation on average of 34 𝑘𝑝𝑐 scales. At low redshift, the median extension after deconvolving the instrumental point spread function is 3.2 𝑘𝑝𝑐, potentially showing evolutionary variations in star formation activity. However, limitations of the spatial resolving power constrain the ability to make any absolute conclusive remarks. It is also found that the QSO/AGN composite has more neutral PAHs than the starbursting and the main sequence galaxies, consistent with the AGN having no contribution to heating the PAH emission, and also consistent with the average PAH emission found on 𝑘𝑝𝑐 scales (i.e. not confined to the nuclear regions). A tentative detection of water vapour emission from the gravitationally lensed Einstein Cross quasar, QSO J2237+0305, is also presented suggesting a strong molecular outflow possibly driven by the active nucleus.

Si pubblica per la prima volta in italiano un saggio cruciale del '32 di Leo Spitzer, Vita in forma di letteratura nella "Dorotea" di Lope de Vega, traduzione di Maria Borriello (che ha discusso una tesi sull'argomento con il sottoscritto), prefazione e note complementari in appendice di R. Gigliucci. Si tratta di un'opera di grande rilievo per l'interpretazione del teatro lopiano e del barocco in generale.First translation in Italy of the essay by Spitzer, with Introduction and notes

This is the first part of an Hα kinematics follow-up survey of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample. The data for 28 galaxies are presented. The observations were done on three different telescopes with Fabry–Perot of New Technology for the Observatoire du mont Megantic (FaNTOmM), an integral field photon-counting spectrometer, installed in the respective focal reducer of each telescope. The data reduction was done through a newly built pipeline with the aim of producing the most homogenous data set possible. Adaptive spatial binning was applied to the data cubes in order to get a constant signal-to-noise ratio across the field of view. Radial velocity and monochromatic maps were generated using a new algorithm, and the kinematical parameters were derived using tilted-ring models.