WISE J224607.56$-$052634.9 (W2246-0526) is a hyperluminous ($L_{\rm bol}\approx 1.7\times 10^{14}~L_\odot$), dust-obscured and radio-quiet quasar at redshift $z=4.6$. It plays a key role in probing the transition stage between dusty starbursts and unobscured quasars in the co-evolution of galaxies and supermassive black holes (SMBHs). To search for the evidence of the jet activity launched by the SMBH in W2246-0526, we performed very long baseline interferometry (VLBI) observations of its radio counterpart with the European VLBI Network (EVN) plus the enhanced Multi Element Remotely Linked Interferometer Network (e-MERLIN) at 1.66 GHz and the Very Long Baseline Array (VLBA) at 1.44 and 1.66 GHz. The deep EVN plus e-MERLIN observations detect a compact (size $\leq32$ pc) sub-mJy component contributing about ten percent of its total flux density, which spatially coincides with the peak of dust continuum and [C II] emissions. Together with its relatively high brightness temperature ($\geq8\times10^{6}$ K), we interpret the component as a consequence of non-thermal radio activity powered by the central SMBH, which likely originates from a stationary jet base. The resolved-out radio emission possibly come from a diffuse jet, quasar-driven winds, or both, while the contribution by star formation activity is negligible. Moreover, we propose an updated geometry structure of its multi-wavelength active nucleus and shed light on the radio quasar selection bias towards the blazars at $z>4$.
Hot dust-obscured galaxies (Hot DOGs) are a luminous, dust-obscured population recently discovered in the WISE All-Sky survey. Multiwavelength follow-up observations suggest that they are mainly powered by accreting supermassive black holes (SMBHs), lying in dense environments, and being in the transition phase between extreme starburst and UV-bright quasars. Therefore, they are good candidates for studying the interplay between SMBHs, star formation and environment. W2246$-$0526 (thereafter, W2246), a Hot DOG at $z\sim4.6$, has been taken as the most luminous galaxy known in the Universe. Rev…
In this work we report the discovery of the hyperluminous galaxy HELP_J100156.75+022344.7 at the photometric redshift of z ~ 4.3. The galaxy was discovered in the Cosmological Evolution Survey (COSMOS) field, one of the fields studied by the Herschel Extragalactic Legacy Project (HELP). We present the spectral energy distribution (SED) of the galaxy and fit it with the CYprus models for Galaxies and their NUclear Spectra (CYGNUS) multi-component radiative transfer models. We find that its emission is dominated by an obscured quasar with a predicted total 1-1000um luminosity of $3.91^{+1.69}_{-…
We utilize a Bayesian approach to fit the observed mid-IR-to-submm/mm spectral energy distributions (SEDs) of 22 WISE-selected and submm-detected, hyperluminous hot dust-obscured galaxies. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are: 1) Hot DOGs in our submm-detected sample are hyperluminous, with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, averagely contributing ~24% of total IR luminosity. 2) Compared to QSO and starburst SED templates, the median SED…
We present ALMA observations and multiwavelength spectral energy distribution (SED) analysis in a WISE-selected, hyperluminous dust-obscured quasar W0533-3401 at $z=2.9$. We derive its physical properties of each component, such as molecular gas, stars, dust and the central supermassive black hole (SMBH). Both the dust continuum at 3 mm and the CO(3-2) line are detected. The derived molecular gas mass $M_{\rm gas}=8.4\times10^{10}\ M_\odot$ and its fraction $f_{\rm gas}=0.7$ suggest that W0533-3401 is gas-rich. The star formation rate (SFR) has been estimated to be $\sim3000-7000\ M_\odot$ yr$…
\emph{Wide-field Infrared Survey Explorer} all-sky survey has discovered a new population of hot dust-obscured galaxies (Hot DOGs), which has been confirmed to be dusty quasars. Previous statistical studies have found significant overdensities of sub-millimeter and mid-IR selected galaxies around Hot DOGs, indicating they may reside in dense regions. Here we present the near-infrared ($J$ and $K_s$ bands) observations over a $7.5'\times 7.5'$ field centered on a Hot DOG W1835$+$4355 at $z \sim 2.3$ using the wide-field infrared camera on the Palomar 200-inch telescope. We use the color criteri…
We present the first X-ray spectrum of a Hot dust-obscured galaxy (DOG), namely W1835+4355 at z ~ 2.3. Hot DOGs represent a very rare population of hyperluminous (>= 10^47 erg/s), dust-enshrouded objects at z > 2 recently discovered in the WISE All Sky Survey. The 40 ks XMM-Newton spectrum reveals a continuum as flat (Gamma ~ 0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe Kalpha emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L(2-10 keV) ~ 2 x 10^44 erg/s is a fr…
We present band 6 ALMA observations of a heavily-obscured radio-loud ($L_{1.4\ \mathrm{GHz}}=10^{25.4}$ W Hz$^{-1}$) AGN candidate at $z_\mathrm{phot}=6.83\pm0.06$ found in the 1.5 deg$^2$ COSMOS field. The ALMA data reveal detections of exceptionally strong [CII]158$μ$m ($z_\mathrm{[CII]}=6.8532$) and underlying dust continuum emission from this object (COS-87259), where the [CII] line luminosity, line width, and 158$μ$m continuum luminosity are comparable to that seen from $z\sim7$ sub-mm galaxies and quasar hosts. The 158$μ$m continuum detection suggests a total infrared luminosity of $9\ti…
Physical properties of hyperluminous, dust-obscured quasars at $z \sim 3$: multiwavelength Spectral Energy Distribution analysis and cold gas content revealed by ALMA
本文基于 ALMA 观测对 16 个 $z \sim 3$ 超亮尘埃遮挡类星体进行多波段 SED 分析，发现其分子气体含量低且消耗快，恒星形成效率高，表明正处于向未遮挡类星体过渡的短暂阶段。
We present a 155ks NuSTAR observation of the $z\sim2$ hot dust-obscured galaxy (hot DOG) W1835+4355. We extracted spectra from the two NuSTAR detectors and analyzed them jointly with the archival XMM PN and MOS spectra. We performed a spectroscopic analysis based on both phenomenological and physically motivated models employing toroidal and spherical geometry for the obscurer. In all the modelings, the source exhibits a Compton-thick column density $N_{\rm H} \gtrsim 10^{24}$ cm$^{-2}$, a 2-10 keV luminosity $L_{2-10}\approx2\times10^{45}$ erg s$^{-1}$ , and a prominent soft excess ($\sim5-10…
Previous studies have shown that WISE-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly Compton-thick AGNs. High obscuration provides us a good chance to study the host morphology of the most luminous AGNs directly. We analyze the host morphology of 18 Hot DOGs at $z\sim3$ using Hubble Space Telescope/WFC3 imaging. We find that Hot DOGs have a high merger fraction ($62\pm 14 \%$). By fitting the surface brightness profiles, we find that the distribution of Sérsic indices in our Hot DOG sample peaks around 2, which suggests that most of …
Hot, Dust-Obscured Galaxies, or "Hot DOGs", are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Predominantly at redshifts 2-3, they include the most luminous known galaxies in the universe. Their high luminosities likely come from accretion onto highly obscured super massive black holes (SMBHs). We have conducted a pilot survey to measure the SMBH masses of five z~2 Hot DOGs via broad H_alpha emission lines, using Keck/MOSFIRE and Gemini/FLAMINGOS-2. We detect broad H_alpha emission in all five Hot DOGs. We find substantial corresponding SMBH masses for these Ho…
ALMA High-J CO Spectroscopy of High-Redshift Galaxies. II. 0.03" Resolution CO Kinematics Reveal Super-Eddington Accretion in a Dust-Obscured Galaxy at z=3.111
Faculty of Engineering, Hokkai-Gakuen University（北海道学园大学工学部）
We present BayeSED, a general purpose tool for doing Bayesian analysis of SEDs by using whatever pre-existing model SED libraries or their linear combinations. The artificial neural networks (ANNs), principal component analysis (PCA) and multimodal nested sampling (MultiNest) techniques are employed to allow a highly efficient sampling of posterior distribution and the calculation of Bayesian evidence. As a demonstration, we apply this tool to a sample of hyperluminous infrared galaxies (HLIRGs). The Bayesian evidences obtained for a pure Starburst, a pure AGN, and a linear combination of Star…
The key ingredient of active galactic nuclei (AGN) unification, the dusty obscuring torus was so far held responsible for the observed mid-infrared (MIR) emission of AGN. However, the best studied objects with VLTI/MIDI show that instead a polar dusty wind is dominating these wavelengths, leaving little room for a torus contribution. But is this wind an ubiquitous part of the AGN? To test this, we conducted a straightforward detection experiment, using the upgraded VLT/VISIR for deep subarcsecond resolution MIR imaging of a sample of nine [O IV]-bright, obscured AGN, all of which were predicte…
We present a new population of z>2 dust-reddened, Type 1 quasars with 0.5<E(B-V)<1.5, selected using near infra-red (NIR) imaging data from the UKIDSS-LAS, ESO-VHS and WISE surveys. NIR spectra obtained using the Very Large Telescope (VLT) for 24 new objects bring our total sample of spectroscopically confirmed hyperluminous (>10^{13}L_0), high-redshift dusty quasars to 38. There is no evidence for reddened quasars having significantly different H$α$ equivalent widths relative to unobscured quasars. The average black-hole masses (~10^9-10^10 M_0) and bolometric luminosities (~10^{47} erg/s) ar…
Using MIRI on-board JWST we present mid-infrared sub-arcsec imaging (MIRIM) and spectroscopy (MRS) of the hyperluminous infrared system SPT0311-58 at z=6.9. MIRI observations are compared with existing ALMA far-infrared continuum and [CII]158$μ$m imaging. Even though the ALMA observations suggests very high star formation rates (SFR) in the eastern (E) and western (W) galaxies of the system, the H$α$ line is not detected. This, together with the detection of the Pa$α$ line, implies very high optical nebular extinction with lower limits of 4.2 (E) and 3.9 mag (W), and even larger 5.6 (E) and 10…
Highly collimated parsec-scale jets, generally linked to the presence of an accretion disk, are a commonly observed phenomenon from revealed low-mass young stellar objects. In the past two decades, only a very few of these objects have been directly (or indirectly) observed towards high-mass (M > 8 M$_{\odot}$) young stellar objects, adding to the growing evidence that disk-mediated accretion is a phenomenon also occurring in high-mass stars, the formation mechanism of which is still poorly understood. Of the observed jets from massive young stars, none is in the optical regime (due to these b…
Mergers of galaxies are thought to cause significant gas inflows to the inner parsecs, which can activate rapid accretion onto supermassive black holes (SMBHs), giving rise to Active Galactic Nuclei (AGN). During a significant fraction of this process, SMBHs are predicted to be enshrouded by gas and dust. Studying 52 galactic nuclei in infrared-selected local Luminous and Ultra-luminous infrared galaxies in different merger stages in the hard X-ray band, where radiation is less affected by absorption, we find that the amount of material around SMBHs increases during the last phases of the merg…
Hot Dust-Obscured Galaxies (Hot DOGs) are hyperluminous ($L_{\mathrm{8-1000\,μm}}>10^{13}\,\mathrm{L_\odot}$) infrared galaxies with extremely high (up to hundreds of K) dust temperatures. The sources powering both their extremely high luminosities and dust temperatures are thought to be deeply buried and rapidly accreting supermassive black holes (SMBHs). Hot DOGs could therefore represent a key evolutionary phase in which the SMBH growth peaks. X-ray observations can be used to study their obscuration levels and luminosities. In this work, we present the X-ray properties of the 20 most-lumin…
We present a detailed study of the X-ray and optical spectra of the luminous Seyfert galaxy Mrk 1393, which revealed variable partial obscuration of the active nucleus. The X-ray spectra obtained by XMM-Newton and Swift show moderate absorption with a column density around 3x10^21 cm^-2, consistent with a dust-reddening interpretation of the steep Balmer decrement seen in recent optical spectra. The X-ray flux in the 0.5 to 2 keV band during the XMM-Newton observation in 2005 and Swift observation in 2006 was a factor 6 brighter than that of the ROSAT All Sky Survey in 1991. In the past 4 year…
We present the analysis of infrared HST and Spitzer data for a sample of 13 FRII radio galaxies at 0.03<z<0.11 that are classified as narrow-line radio galaxies (NLRG). In the context of the unified schemes for active galactic nuclei (AGN), our direct view of the AGN in NLRG is impeded by a parsec-scale dusty torus structure. Our high resolution infrared observations provide new information about the degree of extinction induced by the torus, and the incidence of obscured AGN in NLRG. We find that the point-like nucleus detection rate increases from 25 per cent at 1.025$μ$m, to 80 per cent at …
IRAS F11119+3257 is a quasar-dominated Ultra-Luminous InfraRed Galaxy, with a partially obscured narrow-line seyfert 1 nucleus. In this paper, we present the NIR spectroscopy of F11119+3257, in which we find unusual Paschen emission lines, and metastable He I* $λ$10830 absorption associated with the previously reported atomic sodium and molecular OH mini-BAL (Broad Absorption Line) outflow. Photo-ionization diagnosis confirms previous findings that the outflows are at kilo-parsec scales. Such large-scale outflows should produce emission lines. We indeed find that high-ionization emission lines…
Revealing a multi-zone circumnuclear dust response in UGC~11487 through phase-resolved WISE W1--W2 diagnostics
Main Astronomical Observatory of the NAS of Ukraine（乌克兰国家科学院主天文台）；International Centre for Astronomical, Medical and Ecological Research（国际天文、医学与生态研究中心）
Understanding how super-massive black holes form and grow in the early Universe has become a major challenge since the discovery of luminous quasars only 700 million years after the Big Bang. Simulations indicate an evolutionary sequence of dust-reddened quasars emerging from heavily dust-obscured starbursts that then transition to unobscured luminous quasars by expelling gas and dust. Although the last phase has been identified out to a redshift of 7.6, a transitioning quasar has not been found at similar redshifts owing to their faintness at optical and near-infrared wavelengths. Here we rep…
Observations of a Possible Transient Magnetically Arrested Accretion State in a Nearby Quasar: OQ208
ICRANet（国际相对论天体物理中心）；ICRA, Physics Department, University La Sapienza（罗马大学物理系ICRA）；CSIRO Space and Astronomy（澳大利亚联邦科学与工业研究组织空间与天文部）；INAF, Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；Instituto de Astrofı́sica de Andalucı́a (IAA-CSIC)（安达卢西亚天体物理研究所）；McDonald Observatory, University of Texas at Austin（德克萨斯大学奥斯汀分校麦克唐纳天文台）；Department of Astronomy, University of Texas at Austin（德克萨斯大学奥斯汀分校天文学系）；Crimean Astrophysical Observatory（克里米亚天体物理观测站）；INAF-Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）；National Radio Astronomy Observatory（美国国家射电天文台）；Department of Physics and Astronomy, University of Manitoba（曼尼托巴大学物理与天文系）；Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, CAS（中国科学院高能物理研究所粒子天体物理重点实验室）；Department of Physics University of Crete（克里特大学物理系）；Institute of Astrophysics, FORTH（希腊研究与技术基金会天体物理研究所）；Dipartimento di Fisica & Astronomia, University of Padua（帕多瓦大学物理与天文系）；Department of Physics, University of Maryland Baltimore County（马里兰大学巴尔的摩分校物理系）
Despite the hypothesized similar face-on viewing angles, the infrared emission of type-1 AGNs has diverse spectral energy distribution (SED) shapes that deviate substantially from the well-characterized quasar templates. Motivated by the commonly-seen UV-optical obscuration and the discovery of parsec-scale mid-IR polar dust emission in some nearby AGNs, we develop semi-empirical SED libraries for reddened type-1 AGNs built on the quasar intrinsic templates, assuming low-level extinction caused by an extended distribution of large dust grains. We demonstrate that this model can reproduce the n…
