Quasar host galaxies in the FORS deep field

Villforth, C.; Heidt, J.; Nilsson, K.

doi:10.1051/0004-6361:200809712

Cited by 30 publications

(73 citation statements)

References 45 publications

(88 reference statements)

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“…The same is true for the small number of resolved targets in the previous AO studies by our group (Falomo et al, 2005;2008). Villforth, Heidt & Nilsson (2008) reported the marginal detection of the host galaxy of a single z = 2.75 quasar. Its very low N/H ratio and spectral classification halfway between Type 1 and Type 2 AGN suggest that this object is an obscured quasar.…”

Section: Resultsmentioning

confidence: 99%

The Properties of Quasar Hosts at the Peak of the Quasar Activity

Kotilainen

Falomo

Decarli

et al. 2009

ApJ

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-2 -We present near-infrared imaging obtained with ESO VLT/ISAAC of a sample of 16 low luminosity radio-quiet quasars at the epoch around the peak of the quasar activity (2 < z < 3), aimed at investigating their host galaxies. For 11 quasars, we are able to detect the host galaxies and derive their properties, while for the other five quasars, upper limits to the host luminosity are estimated. The luminosities of the host galaxies of radio-quiet quasars at high redshift are in the range of those of massive inactive elliptical galaxies.This work complements our previous systematic study of quasar hosts aimed to trace the cosmological luminosity evolution of the host galaxies up to z ∼ 2 and extends our pilot study of a few luminous quasars at z > 2. The luminosity trend with cosmic epoch resembles that observed for massive inactive galaxies, suggesting a similar star formation history. In particular, both quasar host galaxies and massive inactive galaxies appear mostly assembled already at the peak age of the quasar activity. This result is of key importance for testing the models of joint formation and evolution of galaxies and their active nuclei.

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Section: Resultsmentioning

confidence: 99%

The Properties of Quasar Hosts at the Peak of the Quasar Activity

Kotilainen

Falomo

Decarli

et al. 2009

ApJ

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“…In contrast, studies such as Villforth et al 2008 andKotilainen et al 2009 find quiescent galaxies that host radio quiet high-z QSOs. These observations are from seeing-limited (0.4-0.5 ′′ ) near-infrared imaging and are limited to disentangling the host galaxy at close angular scales ( 4 kpc).…”

Section: Comparison To Other Type-1 Qsos At Zmentioning

confidence: 88%

PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

Vayner

Wright

et al. 2016

ApJ

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We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z∼2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini-North Observatories using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z=2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a PSF from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at separation of ∼0.2 ′′ (∼1.4 kpc). We detect Hα narrow-line emission for two sources, SDSSJ1029+6510 (z Hα =2.182) and SDSSJ0925+0655 (z Hα =2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate for SDSSJ1029+6510 of 78.4 M ⊙ yr −1 originating from a compact region that is kinematically offset by 290 -350 km s −1 . For SDSSJ0925+0655 we infer a star formation rate of 29 M ⊙ yr −1 distributed over three clumps that are spatially offset by ∼ 7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is 0.3 M ⊙ yr −1 kpc −2 . If we assume typical extinction values for z=2 type-1 QSOs, the dereddened star formation rate for our null detections would be 0.6 M ⊙ yr −1 kpc −2 . These IFS observations indicate that while the central black hole is accreting mass at 10-40% of the Eddington rate, if star formation is present in the host (1.4 -20 kpc) it would have to occur diffusely with significant extinction and not in compact, clumpy regions.

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“…Canalizo & Stockton 2001;Veilleux et al 2009) or high-luminosity quasars at high redshift (e.g. Schramm, Wisotzki & Jahnke 2008;Villforth, Heidt & Nilsson 2008;Kocevski et al 2012). A part of the parameter space that has been poorly explored are low-luminosity AGN at high redshift, this is in particular due to the difficulty in identifying high-redshift low-luminosity AGN.…”

Section: Introductionmentioning

confidence: 99%

The spectral energy distributions, host galaxies and environments of variability-selected active galactic nuclei in GOODS-South

Villforth¹,

Sarajedini

Koekemoer

2012

Monthly Notices of the Royal Astronomical Society

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Variability selection has been proposed as a powerful tool for identifying both low‐luminosity active galactic nuclei (AGN) and those with unusual spectral energy distributions. However, a systematic study of sources selected in such a way has been lacking. In this paper, we present the multiwavelength properties of the variability‐selected AGN in GOODS‐South. We demonstrate that variability selection indeed reliably identifies AGN, predominantly of low luminosity. We find contamination from stars as well as a very small sample of sources that show no sign of AGN activity, their number is consistent with the expected false positive rate. We also study the host galaxies and environments of the AGN in the sample. Disturbed host morphologies are relatively common. The host galaxies span a wide range in the level of ongoing star formation. However, massive starbursts are only present in the hosts of the most luminous AGN in the sample. There is no clear environmental preference for the AGN sample in general but we find that the most luminous AGN on average avoid dense regions while some low‐luminosity AGN hosted by late‐type galaxies are found near the centres of groups. AGN in our sample have closer nearest neighbours than the general galaxy population. We find no indications that major mergers are a dominant triggering process for the moderate‐ to low‐luminosity AGN in this sample. The environments and host galaxy properties instead suggest secular processes, in particular tidal processes at first passage and minor mergers, as likely triggers for the objects studied. This study demonstrates the strength of variability selection for AGN and gives first hints at possibly triggering mechanisms for high‐redshift low‐luminosity AGN.

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Quasar host galaxies in the FORS deep field

Cited by 30 publications

References 45 publications

The Properties of Quasar Hosts at the Peak of the Quasar Activity

The Properties of Quasar Hosts at the Peak of the Quasar Activity

PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

The spectral energy distributions, host galaxies and environments of variability-selected active galactic nuclei in GOODS-South

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