ISO continuum observations of quasars at ${z=1{-}4}$

Oyabu, Shinki; Kawara, Kimiaki; Tsuzuki, Y.; Sofue, Yoshiaki; Sato, Yasunori; Okuda, H.; Taniguchi, Yoshiaki; Shibai, Hiroshi; Gabriel, C.; Hasegawa, Takashi; Nishihara, Eiji

doi:10.1051/0004-6361:20000508

Cited by 4 publications

(6 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observation date was UT 1997 January 13, and the reported fluxes were 5.8 mJy in LW2 (k ¼ 6:7 m) and 15.1 mJy in LW3 (k ¼ 14:3 m). These fluxes seem to be somewhat fainter than our result; however, these observations are not inconsistent if the error of our total flux and the absolute photometric calibration error of ISO observation (15% in Oyabu et al 2001) are considered. Therefore, midinfrared flux variation was not found between two observations of B1422+231.…”

Section: Flux and Spectral Energy Distributioncontrasting

confidence: 79%

“…The resulting fluxes and their 1 errors are also listed in Tables 1 and 2, and our results of mid-infrared fluxes of PG 1115+080 and B1422+231 are graphically presented in Figure 2, where fluxes in other wave bands are also shown for comparison (CASTLES; Barvainis & Ivison 2002;Iwamuro et al 2000;Impey et al 1996Impey et al , 1998Courbin et al 1997;Christian et al 1987;Remy et al 1993;Yee & Bechtold 1996;Yee & Ellingson 1994;Oyabu et al 2001;Patnaik & Narasimha 2001;Patnaik et al 1992). It follows that our mid-infrared fluxes of both QSOs present clear infrared bumps in their SEDs, thereby indicating that the observed mid-infrared fluxes of PG 1115+080 and B1422+ 231 are dominated by thermal emission of a dust torus surrounding the central black hole and accretion disk.…”

Section: Flux and Spectral Energy Distributionmentioning

confidence: 87%

“…The SEDs in Figure 2 are compared with the mean energy distribution (MED) of low-redshift QSOs by Elvis et al (1994), and our mid-infrared fluxes are consistent with the MED, if the dispersion of the SED around the MED is taken into account. Oyabu et al (2001) measured the total flux of B1422+231 in mid-infrared bands using the Infrared Space Observatory (ISO). The observation date was UT 1997 January 13, and the reported fluxes were 5.8 mJy in LW2 (k ¼ 6:7 m) and 15.1 mJy in LW3 (k ¼ 14:3 m).…”

Section: Flux and Spectral Energy Distributionmentioning

confidence: 99%

See 2 more Smart Citations

Subaru Mid‐Infrared Imaging of the Quadruple Lenses PG 1115+080 and B1422+231: Limits on Substructure Lensing

Chiba

Minezaki

Kashikawa

et al. 2005

ApJ

109

114

View full text Add to dashboard Cite

We present mid-infrared imaging at 11.7 m for the quadruple lens systems PG 1115+080 and B1422+231 using the cooled mid-infrared camera and spectrometer (COMICS) attached on the Subaru Telescope. These lensed QSOs are characterized by their anomalous optical and radio flux ratios, as obtained for A1 and A2 images of PG 1115+ 080 and A, B, and C images of B1422+231, respectively, i.e., such flux ratios are hardly able to be reproduced by lens models with a smooth mass distribution. Our mid-infrared observations for these images have revealed that the mid-infrared flux ratio A2/A1 of PG 1115+080 is virtually consistent with smooth lens models (but inconsistent with the optical flux ratio), whereas for B1422+231, the mid-infrared flux ratios among the A, B, and C images are in good agreement with the radio flux ratios. We also identify a clear infrared bump in the spectral energy distributions of these QSOs, thereby indicating that the observed mid-infrared fluxes originate from a hot dust torus around a QSO nucleus. Based on the size estimate of the dust torus, we place limits on the mass of a substructure in these lens systems causing the anomalous optical or radio flux ratios. For PG 1115+080, the mass of a substructure inside an Einstein radius M E is P16 M , corresponding to either a star or a low-mass CDM subhalo having a mass of M SIS 100 P 2:2 ; 10 4 M inside a radius of 100 pc if modeled as a singular isothermal sphere (SIS). For B1422+231, we obtain M E k 209 M , indicating that a CDM subhalo is more likely, having a mass of M SIS 100 k 7:4 ; 10 4 M .

show abstract

Section: Flux and Spectral Energy Distributioncontrasting

confidence: 79%

Section: Flux and Spectral Energy Distributionmentioning

confidence: 87%

Section: Flux and Spectral Energy Distributionmentioning

confidence: 99%

See 1 more Smart Citation

Subaru Mid‐Infrared Imaging of the Quadruple Lenses PG 1115+080 and B1422+231: Limits on Substructure Lensing

Chiba

Minezaki

Kashikawa

et al. 2005

ApJ

109

114

View full text Add to dashboard Cite

show abstract

“…Dust locating at the circumnuclear region is heated by the central engine, and produce near-infrared radiation. Such hot dust is common in Active Galactic Nuclei (AGNs) and quasars at low redshift and also observed in high-redshift quasars (Oyabu et al 2001;Hines et al 2006;Jiang et al 2006). Dust at high redshift is presumably produced as a result of supernova explosions, while dust production would be dominated by mass-loss of late-type stars at low-redshift.…”

Section: Introductionmentioning

confidence: 94%

AKARINEAR- AND MID-INFRARED SPECTROSCOPY OF APM 08279+5255 ATz= 3.91

Oyabu

Kawara

Tsuzuki³

et al. 2009

ApJ

Self Cite

View full text Add to dashboard Cite

We present rest-frame optical/near-infrared spectra of the gravitationally lensed quasar APM 08279+5255 at z = 3.91 that has been taken using the Infrared Camera (IRC) onboard the AKARI infrared satellite. The observed continuum consists of two components; a power-law component dominating optical wavelengths which is the direct light from the central source and thermal emission dominating near-infrared wavelengths which is attributed to the emission from hot dust in the circumnuclear region. The thermal emission well represents optically thick emission by hot dust at T ∼ 1300K with τ 2µm > 2 and apparent mass, M hot > 10M ⊙ . Thus, our observations directly detected the optically thick region of hot dust in APM 08279+5255. HI recombination lines of Hα(0.656µm), Paα(1.875µm), and Paβ(1.282µm) are clearly detected at 3.2, 6.3, and 9.3 µm. Simulations with the photoionization models suggest that APM 08279+5255 has BLR(Broad Line Region) clouds characterized by log n H ∼ 12 − 14 for the gas density, log U ∼ −2 − −6 for the ionization parameter, and E(B − V ) ∼ 0.3 − 0.6 for the broad line region. Thus, optically thick emission of hot dust support an idea on non-spherical distribution of dust near the central source, consistent with the Active Galactic Nuclei model with the dust torus. The temperature of hot dust and flux ratios of these HI lines are similar to those observed in low-redshift † Based on observations with AKARI, a JAXA project with the participation of ESA.

show abstract

“…The lack of any statistically well-defined sample prevented any inferences on the general FIR properties of optically selected quasars. Also, subsequent studies, based on millimeter emission of IRAS QSOs and of high-z optical QSOs (Chini et al 1989;Omont et al 1996;Andreani, Franceschini, & Granato 1999;Carilli et al 2000;Omont et al 2001, and references therein) and on Infrared Space Observatory (ISO) observations (Haas et al 1998(Haas et al , 2000Polletta et al 2000;Oyabu et al 2001), could not address this issue and mainly focussed on the question of the emitting mechanism.…”

Section: Introductionmentioning

confidence: 99%

The Dusty Environment of Quasars: Far-Infrared Properties of Optical Quasars

Andreani

Cristiani

Grazian

et al. 2003

The Astronomical Journal

View full text Add to dashboard Cite

We present Infrared Space Observatory (ISO) far-IR photometry of a complete subsample of optically selected bright quasars belonging to two complete surveys selected through multicolor (U, B, V, R, I ) techniques. The ISOPHOT camera on board the ISO satellite was used to target these quasars at wavelengths of 7.3, 11.5, 60, 100, and 160 lm. Almost two-thirds of the objects were detected at least in one ISOPHOT band. The detection rate is independent of the source redshift, very likely because of the negative K-correction of the far-IR thermal emission. More than a half of the optically selected QSOs show significant emission between 4 and 100 lm in the quasar rest frame. These fluxes have a very likely thermal origin, although in a few objects an additional contribution from a nonthermal component is plausible in the long-wavelength bands. In a color-color diagram these objects span a wide range of properties, from AGNdominated to ULIRG-like. The far-IR composite spectrum of the quasar population presents a broad far-IR bump between 10 and 30 lm and a sharp drop at > 100 lm in the quasar rest frame. The amount of energy emitted in the far-IR is on average a few times larger than that emitted in the blue, and the ratio L FIR /L B increases with the bolometric luminosity. Objects with fainter blue magnitudes have larger ratios between the far-IR ( > 60 lm) fluxes and the blue-band flux, which is attributed to extinction by dust around the central source. No relation between the blue absolute magnitude and the dust color temperature is seen, suggesting that the dominant source of FIR energy could be linked to a concurrent starburst rather than to gravitational energy produced by the central engine.

show abstract

ISO continuum observations of quasars at ${z=1{-}4}$

Cited by 4 publications

References 40 publications

Subaru Mid‐Infrared Imaging of the Quadruple Lenses PG 1115+080 and B1422+231: Limits on Substructure Lensing

Subaru Mid‐Infrared Imaging of the Quadruple Lenses PG 1115+080 and B1422+231: Limits on Substructure Lensing

AKARINEAR- AND MID-INFRARED SPECTROSCOPY OF APM 08279+5255 ATz= 3.91

The Dusty Environment of Quasars: Far-Infrared Properties of Optical Quasars

Contact Info

Product

Resources

About