A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). I. The Optical Counterparts of FIRST Radio Sources

Yamashita, Takuji; Nagao, Tohru; Akiyama, Masayuki; He, Wanqiu; Ikeda, Hiroyuki; Tanaka, Masayuki; Niida, Mana; Kajisawa, Masaru; Nobuhara, Kodai; Lee, Chien‐Hsiu; Morokuma, Tomoki; Toba, Yoshiki; Kawaguchi, Toshihiro; Noboriguchi, Akatoki

doi:10.3847/1538-4357/aae1ac

Cited by 16 publications

(69 citation statements)

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“…Recently, Yamashita et al (2018, Paper I) performed a systematic search for RGs and quasars as a project, so-called "the Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS)." They reported the result of optical identifications of radio sources detected by FIRST with the Hyper Suprime-Cam (HSC; Miyazaki et al 2012Miyazaki et al , 2018) (see also Furusawa et al 2018;Kawanomoto et al 2018;Komiyama et al 2018) Subaru Strategic Program survey (HSC-SSP; Aihara et al 2018a).…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we follow the same definition of RGs and quasars as adopted in Yamashita et al (2018). But we removed stellar objects, i.e., radio-loud quasars that are optically unresolved objects based on optical morphology (see Yamashita et al 2018), and focus only on RGs that have optically resolved morphologies.…”

Section: Introductionmentioning

confidence: 99%

“…This survey consists of three layers: Wide, Deep, and UltraDeep, and this work uses S16A Wide-layer data 1 obtained from 2014 March to 2016 January providing a forced photometry of g-, r-, i-, z-, and y-band with a 5σ limiting magnitude of 26.8, 26.4, 26.4, 25.5, and 24.7, respectively (Aihara et al 2018b). The HSC-SSP Wide-layer covers six fields (XMM-LSS, GAMA09H, WIDE12H, GAMA15H, HEC-TOMAP, and VVDS; see Table 1 in Yamashita et al 2018 for detailed coordinates of each field). The typical seeing is about 0 .6 in the i-band and the astrometric uncertainty is about 40 mas in rms.…”

Section: Introductionmentioning

confidence: 99%

“…The typical seeing is about 0 .6 in the i-band and the astrometric uncertainty is about 40 mas in rms. Taking into account the photometric and astrometric flags, Yamashita et al (2018) eventually extracted 23,795,523 HSC objects in the 154 deg 2 for the cross-matching with FIRST (see Section 2.1 in Yamashita et al 2018, for more detail).…”

Section: Introductionmentioning

confidence: 99%

“…The FIRST project completed radio imaging survey at 1.4 GHz with a spatial resolution of 5 .4 (Becker et al 1995;White et al 1997) covering 10,575 deg 2 that is completely overlapping with the survey footprint of 1 The S16A data (Wide, Deep, and UltraDeep) will be available in 2019 as a public data release 2. Although Yamashita et al (2018) the HSC-SSP Wide-layer, and the final release catalog of FIRST (Helfand et al 2015) is publicly available. Before cross-matching with the HSC, Yamashita et al (2018) made a flux-limited FIRST sample with flux density at 1.4 GHz greater than 1.0 mJy.…”

Section: Introductionmentioning

confidence: 99%

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A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

Toba

Yamashita

Nagao

et al. 2019

ApJS

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We present physical properties of radio galaxies (RGs) with f 1.4GHz > 1 mJy discovered by Subaru Hyper Supreme-Cam (HSC) and VLA Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at 0 < z ≤ 1.7 with HSC counterparts in about 100 deg 2 , we compiled multi-wavelength data of optical, near-infrared (IR), mid-IR, far-IR, and radio (150 MHz). We derived their color excess (E(B − V ) * ), stellar mass, star formation rate (SFR), IR luminosity, the ratio of IR and radio luminosity (q IR ), and radio spectral index (α radio ) that are derived from the SED fitting with CIGALE. We also estimated Eddington ratio based on stellar mass and integration of the best-fit SEDs of AGN component. We found that E(B − V ) * , SFR, and IR luminosity clearly depend on redshift while stellar mass, q IR , and α radio do not significantly depend on redshift. Since optically-faint (i AB ≥ 21.3) RGs that are newly discovered by our RG survey tend to be high redshift, they tend to not only have a large dust extinction and low stellar mass but also have high SFR and AGN luminosity, high IR luminosity, and high Eddington ratio compared to optically-bright ones. The physical properties of a fraction of RGs in our sample seem to differ from a classical view of RGs with massive stellar mass, low SFR, and low Eddington ratio, demonstrating that our RG survey with HSC and FIRST provides us curious RGs among entire RG population.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

Toba

Yamashita

Nagao

et al. 2019

ApJS

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The eROSITA Final Equatorial-Depth Survey (eFEDS)

Brusa

Urrutia

Toba

et al. 2022

A&A

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Theoretical models of the co-evolution of galaxies and active galactic nuclei (AGNs) ascribe an important role in the feedback process to a short, luminous, obscured, and dust-enshrouded phase during which the accretion rate of the supermassive black hole is expected to be at its maximum and the associated AGN-driven winds are also predicted to be maximally developed. To test this scenario, we have isolated a textbook candidate from the eROSITA Final Equatorial-Depth Survey (eFEDS) obtained within the performance and verification program of the eROSITA telescope on board the Spectrum Röntgen Gamma mission. From an initial catalogue of 246 hard X-ray selected sources that are matched with the photometric and spectroscopic information available within the eROSITA and Hyper Suprime-Cam consortia, three candidates quasars in the feedback phase have been isolated applying a diagnostic proposed previously. Only one source (eFEDS J091157.4+014327) has a spectrum already available (from SDSS-DR16, z = 0.603) and it unambiguously shows abroad component (full width at half maximum ~1650 kms−1) in the [OIII]5007 line. The associated observed L[OIII] is ~2.6 × 1042 erg s−1, one to two orders of magnitude higher than that observed in local Seyfert galaxies and comparable to those observed in a sample of z ~ 0.5 type 1 quasars. From the multi-wavelength data available, we derive an Eddington ratio (Lbol/LEdd) of ~0.25 and a bolometric correction in the hard X-ray band of kbol ~ 10, which is lower than the corrections observed for objects at similar bolometric luminosity. These properties, along with the outflow, the high X-ray luminosity, the moderate X-ray obscuration (LX∽1044.8 erg s−1, NH∽2.7 × 1022 cm−2), and the red optical colour, all match the prediction of quasars in the feedback phase from merger-driven models. Forecasting to the full eROSITA all-sky survey with its spectroscopic follow-up, we predict that by the end of 2024, we will have a sample of few hundred such objects at z= 0.5–2.

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eROSITA Final Equatorial-Depth Survey (eFEDS)

Ichikawa

Yamashita

Merloni

et al. 2023

A&A

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We constructed the eROSITA X-ray catalog of radio galaxies discovered by the WERGS survey, made by cross-matching the wide area Subaru/Hyper Suprime-Cam (HSC) optical survey and VLA/FIRST 1.4 GHz radio survey. We report finding 393 eROSITA detected radio galaxies in the 0.5−2 keV band in the eFEDS field covering 140 deg2. Thanks to the wide and medium depth eFEDS X-ray survey down to f0.5 − 2 keV = 6.5 × 10−15 erg s−1 cm−2, the sample contains the rare and most X-ray luminous radio galaxies above the knee of the X-ray luminosity function, spanning 44 < log(L0.5−2 keV(abs,corr)/erg s−1) < 46.5 at 1 < z < 4. The sample also contains the sources around and below the knee for the sources 41 < log(L0.5−2 keV(abs,corr)/erg s−1) < 45 at z < 1. Based on the X-ray properties obtained by the spectral fitting, 37 sources show obscured active galactic nucleus (AGN) signatures with log(NH/cm−2) > 22. These obscured and radio AGN reside in 0.4 < z < 3.2, indicating that they are obscured counterparts of the radio-loud quasar, which were missed in the previous optical quasar surveys. By combining radio and X-ray luminosities, we also investigated the jet production efficiency ηjet = ηradPjet/LAGN,bol by utilizing the jet power of Pjet. We find that there are 14 sources with extremely high jet production efficiency at ηjet ≈ 1. This high ηjet value might be a result of the decreased radiation efficiency of ηrad < 0.1, due to the low accretion rate for those sources, and/or of the boosting due to the decline of LAGN,bol by a factor of 10−100 by keeping Pjet constant in the previous Myr, indicating the experience of the AGN feedback. Finally, inferring the BH masses from the stellar mass, we find that X-ray luminous sources show the excess of the radio emission with respect to the value estimated from the fundamental plane. This radio emission excess cannot be explained by the Doppler boosting alone, and therefore the disk–jet connection of X-ray luminous eFEDS-WERGS is fundamentally different from the conventional fundamental plane which mainly covers the low-accretion regime.

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A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). I. The Optical Counterparts of FIRST Radio Sources

Cited by 16 publications

References 58 publications

A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

The eROSITA Final Equatorial-Depth Survey (eFEDS)

eROSITA Final Equatorial-Depth Survey (eFEDS)

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