We present the mean spectral energy distribution (SED) of a sample of optically selected quasars (QSOs) at redshifts of $1 \le z \le 5$. To derive it, we exploit photometric information from SDSS, UKIDSS, and WISE surveys in combination with a stacking analysis of \textitHerschel, \textitAKARI, and \textitPlanck maps at the location of the QSOs. The near-UV and optical parts of the reconstructed mean rest-frame SED are similar to those found in other studies. However, the SED shows an excess at 1-2 $\mu$m (when compared to the aforementioned SEDs normalized in the near-UV) and a prominent bump around 4-6 $\mu$m, followed by a decrease out to $\sim 20 \,\mu$m and a subsequent far-IR bump. From the fitted SEDs we estimate the average active galactic nuclei (AGN) luminosity $L_\rm AGN$ and star formation rate (SFR) as function of cosmic time, finding typical $L_\rm AGN \sim 10^46 - 10^47$ erg/s and SFR $\sim 50 - 1000\, M_\odot/$yr. We develop mid-IR based criteria to split the QSO sample, finding that these allow us to move along the average relationship in the SFR vs. $L_\rm AGN$ diagram toward increasing AGN luminosities. When interpreted in the context of the in-situ coevolution scenario presented by Lapi et al. 2014, our results suggest that the detection in the far-IR band is an effective criterion to select objects where the star formation is on the verge of being affected by energy/momentum feedback from the central AGN.

Broadband spectral energy distributions of SDSS-selected quasars and of their host galaxies: intense activity at the onset of AGN feedback / Bianchini, Federico; Fabbian, Giulio; Lapi, Andrea; Gonzalez-Nuevo, Joaquin; Gilli, Roberto; Baccigalupi, Carlo. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 871:2(2019), pp. 1-18. [10.3847/1538-4357/aaf86b]

### Broadband spectral energy distributions of SDSS-selected quasars and of their host galaxies: intense activity at the onset of AGN feedback

#### Abstract

We present the mean spectral energy distribution (SED) of a sample of optically selected quasars (QSOs) at redshifts of $1 \le z \le 5$. To derive it, we exploit photometric information from SDSS, UKIDSS, and WISE surveys in combination with a stacking analysis of \textitHerschel, \textitAKARI, and \textitPlanck maps at the location of the QSOs. The near-UV and optical parts of the reconstructed mean rest-frame SED are similar to those found in other studies. However, the SED shows an excess at 1-2 $\mu$m (when compared to the aforementioned SEDs normalized in the near-UV) and a prominent bump around 4-6 $\mu$m, followed by a decrease out to $\sim 20 \,\mu$m and a subsequent far-IR bump. From the fitted SEDs we estimate the average active galactic nuclei (AGN) luminosity $L_\rm AGN$ and star formation rate (SFR) as function of cosmic time, finding typical $L_\rm AGN \sim 10^46 - 10^47$ erg/s and SFR $\sim 50 - 1000\, M_\odot/$yr. We develop mid-IR based criteria to split the QSO sample, finding that these allow us to move along the average relationship in the SFR vs. $L_\rm AGN$ diagram toward increasing AGN luminosities. When interpreted in the context of the in-situ coevolution scenario presented by Lapi et al. 2014, our results suggest that the detection in the far-IR band is an effective criterion to select objects where the star formation is on the verge of being affected by energy/momentum feedback from the central AGN.
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https://iopscience.iop.org/article/10.3847/1538-4357/aaf86b/meta
https://arxiv.org/abs/1806.06516
Bianchini, Federico; Fabbian, Giulio; Lapi, Andrea; Gonzalez-Nuevo, Joaquin; Gilli, Roberto; Baccigalupi, Carlo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/87723