COMPLETE INFRARED SPECTRAL ENERGY DISTRIBUTIONS OF MILLIMETER DETECTED QUASARS ATz> 5

Abstract

We present Herschel far-infrared (FIR) photometry of eleven quasars at redshift z > 5 that have previously been detected at 1.2 mm. We perform full spectral energy distribution (SED) fits over the wavelength range λ rest ∼ 0.1-400 µm for those objects with good Herschel detections. These fits reveal the need for an additional far-infrared (FIR) component besides the emission from a dusty AGNpowered torus. This additional FIR component has temperatures of T FIR ∼ 40-60 K with luminosities of L 8−1000µm ∼ 10 13 L (accounting for 25-60% of the bolometric FIR luminosity). If the FIR dust emission is due to star formation it would suggest star formation rates in excess of 1000 solar masses per year. We show that at long wavelengths (λ rest 50 µm) the contribution of the AGN-powered torus emission is negligible. This explains how previous FIR studies of high-redshift quasars that relied on single component fits to (ground-based) observations at λ obs 350 µm reached T FIR and L FIR values similar to our complete SED fits. Stacking the Herschel data of four individually undetected sources reveals a significant average signal in the PACS bands but not in SPIRE. The average SED of sources with individual Herschel detections shows a striking surplus in near-and mid-infrared emission when compared to common AGN templates. The comparison between two average SEDs (sources with and without individual Herschel detections) matched in the UV/optical indicates that for these objects the strength of the MIR emission may correlate with the strength of the FIR emission.

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

“…The only requirement was that the measured pixels should have a total integration time at least 0.75 times the integration time of that of the source of interest in order to exclude the noisy map edges (e.g. Leipski et al 2013). The 1σ photometric uncertainty of the map is taken to be the 1σ value of the Gaussian fitted to the flux densities measured in these 500 random positions.…”

Herschel Observed Stripe 82 Quasars and Their Host Galaxies: Connections Between Agn Activity and Host Galaxy Star Formation

“…For instance, Ade et al (2011) gave the median value of β for our Galaxy as 1.8; Smith et al (2012) found that β varies from 1.7 to 2.5 in the Andromeda Galaxy using Herschel data. In order to compare FIR temperature with the literature, we fix the β value to 1.6 as suggested in Leipski et al (2013). The free parameters of the FIR dust component are temperature and scale.…”

“…Yet the typical dust temperature at ultra-luminous infrared galaxies (ULIRGs) can be as low as 25-35 K (Hwang et al 2010). Thus, the FIR dust temperature is allowed to vary from 10 to 60 K. The initial temperature is set to be 44 K, the mean FIR dust temperature of the high-z quasars (Beelen et al 2006;Leipski et al 2013). To achieve a reliable temperature, the FIR data should be sampled around the peak of the SED at FIR.…”

“…They found that the warm dust temperatures were around 39-52 K, and the FIR luminosities of ∼10 13 L e . Leipski et al (2013) presented 69 QSOs at z > 5, with a mean cold component temperature of ∼50 K, and a mean value of the FIR emission 10 13 L e . The mean temperature of our sample is 33 ± 5.2 K, which is colder than the dust emission in high-redshift quasars.…”

“…A popular method to distinguish star formation and AGN activity is to rely on Spectral Energy Distribution (SED) models. Some studies involving SED analysis are Elvis et al (1994), Richards et al (2006), Netzer et al (2007), Mor & Netzer (2012), Leipski et al (2013Leipski et al ( , 2014, and Xu et al (2015aXu et al ( , 2015b. In this work, we use a Python-based custom-written SED fitting routine (available upon inquiry).…”