In this paper we present the detection of H2O and OH+ emission in z>3 hot dust-obscured galaxies (Hot DOGs). Using ALMA Band-6 observations of two Hot DOGs, we have detected H2O(2_02-1_11) in W0149+2350, and H2O(3_12-3_03) and the multiplet OH+(1_1-0_1) in W0410-0913. We find that both sources have luminous H2O emission with line luminosities of L_H2O > 2.2x10^8 Lsol and L_H2O = 8.7x10^8 Lsol for W0149+2350 and W0410-0913, respectively. The H2O line profiles are similar to those seen for the neighbouring CO(9-8) line, with linewidths of FWHM ~ 800-1000 km/s. However, the H2O emission seems to be more compact than the CO(9-8). OH+ is detected in emission for W0410-0913, with a FWHM=1000km/s and a line luminosity of L_OH+ = 6.92x10^8 Lsol. The ratio of the observed H2O line luminosity over the IR luminosity, for both Hot DOGs, is consistent with previously observed star forming galaxies and AGN. The H2O/CO line ratio of both Hot DOGs and the OH+/H2O line ratio of W0410-0913 are comparable to those of luminous AGN in the literature. The bright H2O(2_02-1_11), and H2O(3_12-3_03) emission lines are likely due to the combined high star formation levels and luminous AGN in these sources. The presence of OH+ in emission, and the agreement of the observed line ratios of the Hot DOGs with luminous AGN in the literature, would suggest that the AGN emission is dominating the radiative output of these galaxies. However, followup multi-transition observations are needed to better constrain the properties of these systems.
Mid-Infrared (IR) silicate dust bands observed in heavily obscured active galactic nuclei (AGNs) include information on the mineralogical properties of silicate dust. We aim to investigate the mineralogical picture of the circumnuclear region of heavily obscured AGNs to reveal obscured AGN activities through the picture. In our previous study Tsuchikawa et al. (2021), we investigated the properties of silicate dust in heavily obscured AGNs focusing on the mineralogical composition and the crystallinity with Spitzer/IRS 5.3-12 micron spectra. In this study, we model the full-range Spitzer/IRS 5…
The combination of the AKARI and WISE infrared all-sky surveys provides an unique opportunity to identify and characterize the most highly dust obscured AGNs in the universe. Dust-obscured AGNs are not easily detectable and potentially underrepresented in extragalactic surveys due to their high optical extinction, but are readily found in the WISE catalog due to their extremely red mid-IR colors. Combining these surveys with photometry from Pan-STARRS and Herschel, we use SED modeling to characterize the extinction and dust properties of these AGNs. From mid-IR WISE colors, we are able to comp…
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 …
Motivated by recent observational constraints on dust reprocessed emission in star forming galaxies at $z\sim 6$ and above we use the very-large cosmological hydrodynamical simulation \bluetides\ to explore predictions for the amount of dust obscured star formation in the early Universe ($z>8$). \bluetides\ matches current observational constraints on both the UV luminosity function and galaxy stellar mass function and predicts that approximately $90\%$ of the star formation in high-mass ($M_{*}>10^{10}\,{\rm M_{\odot}}$) galaxies at $z=8$ is already obscured by dust. The relationship between …
Hot dust-obscured galaxies (Hot DOGs) are a new population recently discovered in the \wise All-Sky survey. Multiwavelength follow-up observations suggest that they are luminous, dust-obscured quasars at high redshift. Here we present the JCMT SCUBA-2 850 $μm$ follow-up observations of 10 Hot DOGs. Four out of ten Hot DOGs have been detected at $>3σ$ level. Based on the IR SED decomposition approach, we derive the IR luminosities of AGN torus and cold dust components. Hot DOGs in our sample are extremely luminous with most of them having $L_{\rm IR}^{\rm tot}>10^{14} L_\odot$. The torus emissi…
The total star formation budget of galaxies consists of the sum of the unobscured star formation, as observed in the rest-frame ultraviolet (UV), together with the obscured component that is absorbed and re-radiated by dust grains in the infrared. We explore how the fraction of obscured star formation depends on stellar mass for mass-complete samples of galaxies at $0<z<2.5$. We combine GALEX and WISE photometry for SDSS-selected galaxies with the 3D-HST treasury program and Spitzer/MIPS 24$μ$m photometry in the well-studied 5 extragalactic CANDELS fields. We find a strong dependence of the fr…
Over the past decades, rest-frame ultraviolet (UV) observations have provided large samples of UV luminous galaxies at redshift (z) greater than 6, during the so-called epoch of reionization. While a few of these UV identified galaxies revealed significant dust reservoirs, very heavily dust-obscured sources at these early times have remained elusive. They are limited to a rare population of extreme starburst galaxies, and companions of rare quasars. These studies conclude that the contribution of dust-obscured galaxies to the cosmic star formation rate density at $z>6$ is sub-dominant. Recent …
The bulk of the star-formation rate density peak at cosmic noon was obscured by dust. How accurately we can assess the role of dust obscured star-formation is affected by inherent biases in our empirical methods -- both those that rely on direct dust emission and those that rely on the inferred dust attenuation of starlight. We use a library of hydrodynamic simulations with radiative transfer to explore these biases. We find that for IR luminous galaxies that are in rapidly quenching systems (e.g. post-coalescence) standard luminosity-to-SFR relations can strongly overestimate the true SFRs. W…
The WISE mission has unveiled a rare population of high-redshift ($z=1-4.6$), dusty, hyper-luminous galaxies, with infrared luminosities $L_{\rm IR} > 10^{13}~L_{\odot}$, and sometimes exceeding $10^{14}~L_{\odot}$. Previous work has shown that their dust temperatures and overall far-IR SEDs are significantly hotter than expected for star-formation. We present here an analysis of the rest-frame optical through mid-IR SEDs for a large sample of these so-called "Hot, Dust-Obscured Galaxies" (Hot DOGs). We find that the SEDs of Hot DOGs are generally well modeled by the combination of a luminous,…
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…
Cosmic dust is an essential component shaping both the evolution of galaxies and their observational signatures. How quickly dust builds up in the early Universe remains an open question that requires deep observations at (sub-)millimeter wavelengths to resolve. Here we use Atacama Large Millimeter Array observations of 45 galaxies from the Reionization Era Bright Emission Line Survey (REBELS) and its pilot programs, designed to target [CII] and dust emission in UV-selected galaxies at $z\sim7$, to investigate the dust content of high-redshift galaxies through a stacking analysis. We find that…
JWST Spectroscopic View of a Rapidly Growing Dust-obscured Quasar at $z \sim 4$: Effect of Dust Extinction Correction on Black Hole Mass and Eddington Ratio Estimation
We make use of ALMA continuum observations of $15$ luminous Lyman-break galaxies at $z$$\sim$$7$$-$$8$ to probe their dust-obscured star-formation. These observations are sensitive enough to probe to obscured SFRs of $20$ $M_{\odot}$$/$$yr$ ($3σ$). Six of the targeted galaxies show significant ($\geq$$3$$σ$) dust continuum detections, more than doubling the number of known dust-detected galaxies at $z$$>$$6.5$. Their IR luminosities range from $2.7$$\times$$10^{11}$ $L_{\odot}$ to $1.1$$\times$$10^{12}$ $L_{\odot}$, equivalent to obscured SFRs of $20$ to $105$ $M_{\odot}$$/$$yr$. We use our re…
We report the results of a pilot study of CO$(4-3)$ emission line of three {\it WISE}-selected hyper-luminous, dust-obscured quasars (QSOs) with sensitive ALMA Band 3 observations. These obscured QSOs with $L_{\rm bol}>10^{14}L_\odot$ are among the most luminous objects in the universe. All three QSO hosts are clearly detected both in continuum and in CO$(4-3)$ emission line. Based on CO$(4-3)$ emission line detection, we derive the molecular gas masses ($\sim 10^{10-11}$ M$_\odot$), suggesting that these QSOs are gas-rich systems. We find that three obscured QSOs in our sample follow the simi…
An analytical approach is proposed to study the evolution of the star-forming galaxy (SFG) main sequence (MS) and the fraction of dust-obscured SF up to $z\sim4$. Far-ultraviolet (FUV) and infrared (IR) star formation rates, SFRs, are described as conditional probability functions of $M_{\ast}$. We convolve them with the galaxy stellar mass function (GSMF) of SFGs to derive the FUV and IR LFs. The 2 SF modes formalism is used to describe starburst galaxies. By fitting observed FUV and IR LFs, the parametrization of SFR$_{\rm FUV}-M_{\ast}$ and SFR$_{\rm IR}-M_{\ast}$ are constrained. Our deriv…
Heavily obscured active galactic nuclei (AGNs) are known to show deep silicate absorption features in the mid-infrared (IR) wavelength range of 10--20~$μ$m. The detailed profiles of the features reflect the properties of silicate dust, which are likely to include information on AGN activities obscured by large amounts of dust. In order to reveal AGN activities obscured by large amounts of dust, we select 115 mid-IR spectra of heavily obscured AGNs observed by Spitzer/IRS, and systematically analyze the composition of silicate dust by spectral fitting using the 10~$μ$m amorphous and 23~$μ$m cry…
We present the first results from the 2mm Mapping Obscuration to Reionization (MORA) survey, the largest ALMA contiguous blank-field survey to-date with a total area of 184 sq. arcmin and the only at 2mm to search for dusty star-forming galaxies (DSFGs). We use the 13 sources detected above 5sigma to estimate the first ALMA galaxy number counts at this wavelength. These number counts are then combined with the state-of-the-art galaxy number counts at 1.2mm and 3mm and with a backward evolution model to place constraints on the evolution of the IR luminosity function and dust-obscured star form…
We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z <= 0.08) catalog of visually-selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2x10^10 Msun, we find that major mergers (interactions) are 5-17 (3-5) times more likely to have red [3.4]-[4.6] colors associated with dust-obscured or `dusty' AGNs, compared to non-merging galaxies with similar masses. Using published fiber spectral dia…
We present 65 extremely dust-obscured galaxies from the UltraVISTA DR3 survey of the COSMOS field at $1<z<4$. In contrast to other studies of dusty galaxies, we select our sample based on dust attenuation measured by UV-MIR spectral energy distribution (SED) modeling that allows for extreme attenuation levels. We construct our sample by making cuts at $1 \le z \le 4$, A$_V \ge 3$, and log(M$_*$/M$_\odot$)$ \ge 10.5$. This method reliably selects galaxies exhibiting independent indicators of significant dust content, including FIR detection rates. We perform panchromatic SED modeling with match…
It is not clear whether gamma-ray bursts (GRBs) are unbiased tracers of cosmic star formation at $z > 2$. Since dusty starburst galaxies are significant contributors to the cosmic star formation at these redshifts, they should form a major part of the GRB host population. However, recent studies at $z \leq 2$ have shown that the majority of the star formation activity in GRB hosts is not obscured by dust. Here, we investigate the galaxy-scale dust obscuration in $z \sim 2-3.5$ GRB hosts pre-selected to have high-resolution, high signal-to-noise afterglow spectra in the rest-frame ultraviolet (…
The existence of intermediate-width emission line regions (IELRs) in active galactic nuclei has been discussed for over two decades. A consensus, however, is yet to be arrived at due to the lack of convincing evidence for their detection. We present a detailed analysis of the broadband spectrophotometry of the partially obscured quasar OI 287. The ultraviolet intermediate-width emission lines (IELs) are very prominent, in high contrast to the corresponding broad emission lines (BELs) which are heavily suppressed by dust reddening. Assuming that the IELR is virialized, we estimated its distance…
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…
Estimators of Bolometric Luminosity and Black Hole Mass with Mid-infrared Continuum Luminosities for Dust-obscured Quasars: Prevalence of Dust-obscured SDSS Quasars
Obscuration of quasars by accreted gas and dust, or dusty intervening galaxies, can cause active galactic nuclei (AGN) to be missed in optically-selected surveys. Radio observations can overcome this dust bias. In particular, radio surveys searching for HI absorption inform us on how the AGN can impact on the cold neutral gas medium within the host galaxy, or the population of intervening galaxies through the observed line of sight gas kinematics. We present the results of a HI absorption line survey at $0.4 < z < 1$ towards 34 obscured quasars with the Australian SKA Pathfinder (ASKAP) commis…
Galaxy mergers and gas accretion from the cosmic web drove the growth of galaxies and their central black holes at early epochs. We report spectroscopic imaging of a multiple merger event in the most luminous known galaxy, WISE J224607.56-052634.9 (W2246-0526), a dust-obscured quasar at redshift 4.6, 1.3 Gyr after the Big Bang. Far-infrared dust continuum observations show three galaxy companions around W2246-0526 with disturbed morphologies, connected by streams of dust likely produced by the dynamical interaction. The detection of tidal dusty bridges shows that W2246-0526 is accreting its ne…
We present synthetic far- and near-ultraviolet (FUV and NUV) maps of M31, both with and without dust reddening. These maps were constructed from spatially-resolved star formation histories (SFHs) derived from optical Hubble Space Telescope imaging of resolved stars, taken as part of the Panchromatic Hubble Andromeda Treasury program. We use stellar population synthesis modeling to generate synthetic UV maps with projected spatial resolution of $\sim$100 pc ($\sim$24 arcseconds) The predicted UV flux agrees well with the observed flux, with median ratios between the modeled and observed flux of…
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…
A randomly chosen star in today's Universe is most likely to live in a galaxy with a stellar mass between that of the Milky Way and Andromeda. Yet it remains uncertain how the structural evolution of these bulge-disk systems proceeded. Most of the unobscured star formation we observe building Andromdeda progenitors at 0.7<z<1.5 occurs in disks, but >90% of their star formation is reprocessed by dust and remains unaccounted for. Here we map 500micron dust continuum emission in an Andromeda progenitor at z=1.25 to probe where it is growing through dust-obscured star formation. Combining resolved…
We present Atacama Large Millimeter/Submillimeter Array observations of the rest-frame far-infrared (FIR) dust continuum emission of six bright Lyman-break galaxies (LBGs) at $z \simeq 7$. One LBG is detected ($5.2σ$ at peak emission), while the others remain individually undetected at the $3σ$ level. The average FIR luminosity of the sample is found to be $L_{\rm FIR} \simeq 2 \times 10^{11}\,{\rm L}_{\odot}$, corresponding to an obscured star-formation rate (SFR) that is comparable to that inferred from the unobscured UV emission. In comparison to the infrared excess (IRX$\,=L_{\rm FIR}/L_{\…
The coevolution of galaxies and their central supermassive black holes is a subject of intense research. A class of objects, the dust-obscured galaxies (DOGs) are particularly interesting in this respect as they are thought to represent a short evolutionary phase when violent star formation activity in the host galaxy may coexist with matter accretion onto the black hole powering the active nucleus. Here we investigate different types of DOGs classified by their mid-infrared spectral energy distributions to reveal whether they can be distinguished by their arcsec-scale radio properties. Radio …
Context. Although heavily obscured active galactic nuclei (AGNs) have been found by many observational studies, the properties of the surrounding dust are poorly understood. Using AKARI/IRC spectroscopy, we discover a new sample of a heavily obscured AGN in LEDA 1712304 which shows a deep spectral absorption feature due to silicate dust. Aims. We study the infrared (IR) spectral properties of circumnuclear silicate dust in LEDA 1712304. Methods. We perform IR spectral fitting, considering silicate dust properties such as composition, porosity, size and crystallinity. Spectral energy distributi…
Modeling the JWST MIRI Counts, Insights Into the Source Properties and Role of Dust-Obscured AGN
Tufts University（塔夫茨大学）；Université de Strasbourg, CNRS, Observatoire Astronomique de Strasbourg（斯特拉斯堡大学、法国国家科学研究中心、斯特拉斯堡天文台）；Winona State University（威诺纳州立大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Space Telescope Science Institute（太空望远镜科学研究所）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；University of Arizona（亚利桑那大学）；California Institute of Technology（加州理工学院）
The co-evolution between black holes and galaxies suggests that feedback of active galactic nuclei influence host galaxies through ejecting radiative and kinetic energies to surroundings. Larger scale outflow in local universe are frequently observed by spatially resolved spectroscopy, while smaller scale outflow cannot be directly resolved by current observations. At the scale of the dusty torus, radiative and kinetic energies ejected from the central active nucleus interact with the materials. However, observations of such outflow are rarely reported due to the lack detection of unambiguousl…
Dust-obscured galaxies (DOGs) with extreme infrared luminosities may represent a key phase in the co-evolution of galaxies and supermassive black holes. We select 12 DOGs at $0.3\lesssim z\lesssim1.0$ with broad Mg II or H$β$ emission lines and investigate their X-ray properties utilizing snapshot observations ($\sim3~\mathrm{ks}$ per source) with Chandra. By assuming that the broad lines are broadened due to virial motions of broad-line regions, we find that our sources generally have high Eddington ratios ($λ_\mathrm{Edd}$). Our sources generally have moderate intrinsic X-ray luminosities ($…
We analyse the physical properties of 121 SNR $\geq$ 5 sub-millimetre galaxies (SMGs) from the STUDIES 450-$μ$m survey. We model their UV-to-radio spectral energy distributions using MAGPHYS+photo-$z$ and compare the results to similar modelling of 850-$μ$m-selected SMG sample from AS2UDS, to understand the fundamental physical differences between the two populations at the observed depths. The redshift distribution of the 450-$μ$m sample has a median of $z$ = 1.85 $\pm$ 0.12 and can be described by strong evolution of the far-infrared luminosity function. The fainter 450-$μ$m sample has $\sim…
Evolution of the infrared luminosity function and its corresponding dust-obscured star formation rate density out to z~6
Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University（尼古拉·哥白尼大学物理、天文与信息学学院天体物理研究所）；National Centre for Nuclear Research（国家核研究中心）；Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh（爱丁堡大学天体物理研究所皇家天文台）；Astronomical Observatory Institute, Faculty of Physics and Astronomy, Adam Mickiewicz University（亚当·密茨凯维奇大学物理与天文学学院天文台研究所）
Dense Ionized Outflow with Five Narrow Components in a Dust-obscured Galaxy
Ehime University（爱媛大学）；Amanogawa Galaxy Astronomy Research Center, Kagoshima University（鹿儿大学银河天文学研究中心）；Ritsumeikan University（立命馆大学）；Academia Sinica Institute of Astronomy and Astrophysics（中央研究院天文及天文物理研究所）；Kobe University（神户大学）
We present band 6 ALMA observations of a heavily-obscured radio-loud ($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 $9\ti…
We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of ~4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158μm obtained with the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE). We study the connection between the ultraviolet (UV) spectral slope ($β$), stellar mass (M_*), and infrared excess (IRX=L_IR/L_UV). Twenty-three galaxies are individually detected in the continuum at >3.5 sigma significance. We perform a stac…
We present the X-ray properties of 108 Dust-Obscured Galaxies (DOGs; F$_{24 μm}$/F$_{R} >$ 1000) in the COSMOS field, all of which detected in at least three far-infrared bands with the Herschel Observatory. Out of the entire sample, 22 are individually detected in the hard 2-8 keV X-ray band by the Chandra COSMOS Legacy survey, allowing us to classify them as AGN. Of them, 6 (27%) are Compton Thick AGN candidates with column densities N$_{H}$$>$10$^{24}$ cm$^{-2}$ while 15 are moderately obscured AGNs with 10$^{22}$ $<$ N$_{H}$ $<$ 10$^{24}$ cm$^{-2}$. Additionally, we estimate AGN contributi…
Dust Obscured Galaxies (DOGs), which are observationally characterized as faint in the optical and bright in the infrared, are the final stage of galaxy mergers and are essential objects in the evolution of galaxies and active galactic nuclei (AGNs). However, the relationship between torus-scale gas dynamics around AGNs and DOGs lifetime remain unclear. We obtained evolution of the spectral energy distributions (SEDs) of a galaxy merger system with AGN feedback, from post-processed pseudo-observations based on an N-body/Smoothed Particle Hydrodynamics (SPH) simulation. We focused on a late sta…
We report on observations of redshifted CO(1-0) line emission and observed-frame $\rm\sim$ 30GHz radio continuum emission from five ultra-luminous, mid-IR selected hot, Dust-Obscured Galaxies (Hot DOGs) at $z\rm\gtrsim$ 3 using the Karl G. Jansky Very Large Array. We detect CO(1-0) line emission in all five Hot DOGs, with one of them at high signal to noise. We analyse FIR-radio spectral energy distributions, including dust, free-free and synchrotron emission for the galaxies. We find that most of the 115 GHz rest-frame continuum is mostly due to synchrotron or free-free emission, with only a …
\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 have observed 104 gravitationally-lensed quasars at $z\sim1-4$ with Herschel/SPIRE, the largest such sample ever studied. By targeting gravitational lenses, we probe intrinsic far-infrared (FIR) luminosities and star formation rates (SFRs) more typical of the population than the extremely luminous sources that are otherwise accessible. We detect 72 objects with Herschel/SPIRE and find 66 percent (69 sources) of the sample have spectral energy distributions (SEDs) characteristic of dust emission. For 53 objects with sufficiently constrained SEDs, we find a median effective dust temperature o…
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 Int…
Our current knowledge of star formation and accretion luminosity at high-redshift (z>3-4), as well as the possible connections between them, relies mostly on observations in the rest-frame ultraviolet (UV), which are strongly affected by dust obscuration. Due to the lack of sensitivity of past and current infrared (IR) instrumentation, so far it has not been possible to get a glimpse into the early phases of the dust-obscured Universe. Among the next generation of IR observatories, SPICA, observing in the 12-350 micron range, will be the only facility that can enable us to make the required le…
Radio observations being insensitive to the dust-obscuration, have been exploited to unveil the population of Active Galactic Nuclei (AGN) residing in galaxies with large dust content. In this paper, we investigate the radio characteristics of 321 dust-obscured galaxies (DOGs; S$_{\rm 24 μm}$/S$_{\rm r band}$ $\geq$1000) by using mainly deep band-3 (250$-$550 MHz) observations from the upgraded Giant Metrewave Radio Telescope (uGMRT) and 1.5 GHz Jansky Very Large Array (JVLA) observations. We find that, for our sample of DOGs, deep (median noise-rms $=$ 30 $μ$Jy beam$^{-1}$) 400 MHz band-3 uGM…
We propose an observational test for gravitationally recoiling supermassive black holes (BHs) in active galactic nuclei, based on a correlation between the velocities of BHs relative to their host galaxies, |Δv|, and their obscuring dust column densities, Σ_{dust} (both measured along the line of sight). We use toy models for the distribution of recoil velocities, BH trajectories, and the geometry of obscuring dust tori in galactic centres, to simulate 2.5x10^5 random observations of recoiling quasars. BHs with recoil velocities comparable to the escape velocity from the galactic centre remain…
