arXiv subjects

Peter R. M. Eisenhardt

Publications and source records attributed to Peter R. M. Eisenhardt.

At least 37 records · Page 2Linked to original sources

arXiv2022

Imaging Polarization of the Blue-Excess Hot Dust-Obscured Galaxy WISE J011601.41-050504.0

We report on VLT/FORS2 imaging polarimetry observations in the $R_{\rm special}$ band of WISE J011601.41-050504.0 (W0116-0505), a heavily obscured hyper-luminous quasar at $z=3.173$ classified as a Hot, Dust-Obscured Galaxy (Hot DOG) based on its mid-IR colors. Recently, Assef et al. (2020) identified W0116-0505 as having excess rest-frame optical/UV emission, and concluded this excess emission is most likely scattered light from the heavily obscured AGN. We find that the broad-band rest-frame UV flux is strongly linearly polarized (10.8$\pm$1.9\%, with a polarization angle of 74$\pm$9~deg), confirming this conclusion. We analyze these observations in the context of a simple model based on scattering either by free electrons or by optically thin dust, assuming a classical dust torus with polar openings. Both can replicate the degree of polarization and the luminosity of the scattered component for a range of geometries and column densities, but we argue that optically thin dust in the ISM is the more likely scenario. We also explore the possibility that the scattering medium corresponds to an outflow recently identified for W0116-0505. This is a feasible option if the outflow component is bi-conical with most of the scattering occurring at the base of the receding outflow. In this scenario the quasar would still be obscured even if viewed face on, but might appear as a reddened type 1 quasar once the outflow has expanded. We discuss a possible connection between blue-excess Hot DOGs, extremely red quasars (ERQs), reddened type 1 quasars, and unreddened quasars that depends on a combination of evolution and viewing geometry.

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arXiv2022

Significant Molecular Gas Deficiencies in Star-forming Cluster Galaxies at $z\sim1.4$

We present the average gas properties derived from ALMA Band 6 dust continuum imaging of 126 massive (log $M_{\star} / M_{\odot} \gtrsim 10.5$), star-forming cluster galaxies across 11 galaxy clusters at $z=1-1.75$. Using stacking analysis on the ALMA images, combined with UV-far-infrared data, we quantify the average infrared SEDs and gas properties (molecular gas masses, $M_{\rm mol}$; gas depletion timescales, $τ_{\rm depl}$; and gas fractions, f$_{\rm gas}$) as a function of cluster-centric radius and properties including stellar mass and distance from the Main Sequence. We find a significant dearth in the ALMA fluxes relative to that expected in the field $-$ with correspondingly low $M_{\rm mol}$ and f$_{\rm gas}$ and short $τ_{\rm depl}$ $-$ with weak or no dependence on cluster-centric radius out to twice the virial radius. The Herschel+ALMA SEDs indicate warmer dust temperatures ($\sim36-38$ K) than coeval field galaxies ($\sim30$ K). We perform a thorough comparison of the cluster galaxy gas properties to field galaxies, finding deficits of 2-3x, 3-4x, and 2-4x in $M_{\rm mol}$, $τ_{\rm depl}$, and f$_{\rm gas}$ compared to coeval field stacks and larger deficits compared to field scaling relations built primarily on detections. The cluster gas properties derived here are comparable with stacking analyses in (proto-)clusters in the literature and at odds with findings of field-like $τ_{\rm depl}$ and enhanced f$_{\rm gas}$ reported using CO and dust continuum detections. Our analysis suggests that environment has considerable impact on gas properties out to large radii, in good agreement with cosmological simulations which project gas depletion begins beyond the virial radius and largely completes by first passage of the cluster core.

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arXiv2021

The Massive and Distant Clusters of WISE Survey XI: Stellar Mass Fractions and Luminosity Functions of MaDCoWS Clusters at $z \sim 1$

We present stellar mass fractions and composite luminosity functions (LFs) for a sample of \Ncl\ clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) at a redshift range of $0.951 \leq z \leq 1.43$. Using SED fitting of optical and deep mid-infrared photometry, we establish the membership of objects along the lines-of-sight to these clusters and calculate the stellar masses of member galaxies. We find stellar mass fractions for these clusters largely consistent with previous works, including appearing to display a negative correlation with total cluster mass. We measure a composite $3.6~\mathrm{μm}$ LF down to $m^*+2.5$ for all 12 clusters. Fitting a Schechter function to the LF, we find a characteristic $3.6~\mathrm{μm}$ magnitude of $m^*=19.83\pm0.12$ and faint-end slope of $α=-0.81\pm0.10$ for the full sample at a mean redshift of $\bar{z} = 1.18$. We also divide the clusters into high- and low-redshift bins at $\bar{z}=1.29$ and $\bar{z}=1.06$ respectively and measure a composite LF for each bin. We see a small, but statistically significant evolution in $m^*$ and $α$ -- consistent with passive evolution -- when we study the joint fit to the two parameters, which is probing the evolution of faint cluster galaxies at $z\sim1$. This highlights the importance of deep IR data in studying the evolution of cluster galaxy populations at high-redshift.

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arXiv2021

Kinematics and Star Formation of High-Redshift Hot Dust-Obscured Quasars as Seen by ALMA

Hot, dust-obscured galaxies (Hot DOGs) are a population of hyper-luminous obscured quasars identified by WISE. We present ALMA observations of the [CII] fine-structure line and underlying dust continuum emission in a sample of seven of the most extremely luminous (EL; L$_{\rm bol}$ $\ge$ 10$^{14}$ L$_\odot$) Hot DOGs, at redshifts z ~ 3.0-4.6. The [CII] line is robustly detected in four objects, tentatively in one, and likely red-shifted out of the spectral window in the remaining two based on additional data. On average, [CII] is red-shifted by ~ 780 km/s from rest-frame ultraviolet emission lines. EL Hot DOGs exhibit consistently very high ionized gas surface densities, with $Σ_{\rm [CII]}$ ~ 1-2 x 10$^{9}$ L$_\odot$ kpc$^{-2}$; as high as the most extreme cases seen in other high-redshift quasars. As a population, EL Hot DOG hosts seem to be roughly centered on the main-sequence of star forming galaxies, but the uncertainties are substantial and individual sources can fall above and below. The average, intrinsic [CII] and dust continuum sizes (FWHMs) are ~ 2.1 kpc and ~ 1.6 kpc, respectively, with a very narrow range of line-to-continuum size ratios, 1.61 $\pm$ 0.10, suggesting they could be linearly proportional. The [CII] velocity fields of EL Hot DOGs are diverse: from barely rotating structures, to resolved hosts with ordered, circular motions, to complex, disturbed systems that are likely the result of ongoing mergers. In contrast, all sources display large line-velocity dispersions, FWHM $\gtrsim$ 500 km/s, which on average are larger than optically and IR-selected quasars at similar or higher redshifts. We argue that one possible hypothesis for the lack of a common velocity structure, the systematically large dispersion of the ionized gas, and the presence of nearby companion galaxies may be that, rather than a single event, the EL Hot DOG phase could be recurrent.

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arXiv2021

New Candidate Extreme T Subdwarfs from the Backyard Worlds: Planet 9 Citizen Science Project

Schneider et al. (2020) presented the discovery of WISEA J041451.67-585456.7 and WISEA J181006.18-101000.5, which appear to be the first examples of extreme T-type subdwarfs (esdTs; metallicity <= -1 dex, T_eff <= 1400 K). Here we present new discoveries and follow-up of three T-type subdwarf candidates, with an eye toward expanding the sample of such objects with very low metallicity and extraordinarily high kinematics, properties that suggest membership in the Galactic halo. Keck/NIRES near-infrared spectroscopy of WISEA J155349.96+693355.2, a fast-moving object discovered by the Backyard Worlds: Planet 9 citizen science project, confirms that it is a mid-T subdwarf. With H_W2 = 22.3 mag, WISEA J155349.96+693355.2 has the largest W2 reduced proper motion among all spectroscopically confirmed L and T subdwarfs, suggesting that it may be kinematically extreme. Nevertheless, our modeling of the WISEA J155349.96+693355.2 near-infrared spectrum indicates that its metallicity is only mildly subsolar. In analyzing the J155349.96+693355.2 spectrum, we present a new grid of low-temperature, low-metallicity model atmosphere spectra. We also present the discoveries of two new esdT candidates, CWISE J073844.52-664334.6 and CWISE J221706.28-145437.6, based on their large motions and colors similar to those of the two known esdT objects. Finding more esdT examples is a critical step toward mapping out the spectral sequence and observational properties of this newly identified population.

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arXiv2020

The CatWISE2020 Catalog

The CatWISE2020 Catalog consists of 1,890,715,640 sources over the entire sky selected from WISE and NEOWISE survey data at 3.4 and 4.6 $μ$m (W1 and W2) collected from 2010 Jan. 7 to 2018 Dec. 13. This dataset adds two years to that used for the CatWISE Preliminary Catalog (Eisenhardt et al., 2020), bringing the total to six times as many exposures spanning over sixteen times as large a time baseline as the AllWISE catalog. The other major change from the CatWISE Preliminary Catalog is that the detection list for the CatWISE2020 Catalog was generated using ${\it crowdsource}$ (Schlafly et al. 2019), while the CatWISE Preliminary Catalog used the detection software used for AllWISE. These two factors result in roughly twice as many sources in the CatWISE2020 Catalog. The scatter with respect to ${\it Spitzer}$ photometry at faint magnitudes in the COSMOS field, which is out of the Galactic plane and at low ecliptic latitude (corresponding to lower WISE coverage depth) is similar to that for the CatWISE Preliminary Catalog. The 90% completeness depth for the CatWISE2020 Catalog is at W1=17.7 mag and W2=17.5 mag, 1.7 mag deeper than in the CatWISE Preliminary Catalog. From comparison to ${\it Gaia}$, CatWISE2020 motions are accurate at the 20 mas yr$^{-1}$ level for W1$\sim$15 mag sources, and at the $\sim100$ mas yr$^{-1}$ level for W1$\sim$17 mag sources. This level of precision represents a 12$\times$ improvement over AllWISE. The CatWISE catalogs are available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive.

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arXiv2020

Measuring the total infrared light from galaxy clusters at z=0.5-1.6: connecting stellar populations to dusty star formation

Massive galaxy clusters undergo strong evolution from z~1.6 to z~0.5, with overdense environments at high-z characterized by abundant dust-obscured star formation and stellar mass growth which rapidly give way to widespread quenching. Data spanning the near- to far-infrared (IR) spectrum can directly trace this transformation; however, such studies have largely been limited to the massive galaxy end of cluster populations. In this work, we present ``total light" stacking techniques spanning 3.4-500μm aimed at revealing the total cluster IR emission, including low mass members and potential intracluster dust. We detail our procedures for WISE, Spitzer, and Herschel imaging, including corrections to recover the total stacked emission in the case of high fractions of detected galaxies. We apply our stacking techniques to 232 well-studied massive (log M200/Msun~13.8) clusters across multiple z bins, recovering extended cluster emission at all wavelengths, typically at >5sigma. We measure the averaged near- to far-IR radial profiles and SEDs, quantifying the total stellar and dust content. The near-IR radial profiles are well described by an NFW model with a high (c~7) concentration parameter. Dust emission is similarly concentrated, albeit suppressed at small radii (r<0.2Mpc). The measured SEDs lack warm dust, consistent with the colder SEDs expected for low mass galaxies. We derive total stellar masses consistent with the theoretical Mhalo-M_star relation and specific-star formation rates that evolve strongly with redshift, echoing that of massive (log Mstar/Msun>10) cluster galaxies. Separating out the massive galaxy population reveals that the majority of cluster far-IR emission (~70-80%) is provided by the low mass constituents, which differs from field galaxies. This effect may be a combination of mass-dependent quenching and excess dust in low mass cluster galaxies.

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arXiv2020

The Massive and Distant Clusters of WISE Survey: SZ effect Verification with the Atacama Compact Array -- Localization and Cluster Analysis

The Massive and Distant Clusters of WISE Survey (MaDCoWS) provides a catalog of high-redshift ($0.7\lesssim z\lesssim 1.5$) infrared-selected galaxy clusters. However, the verification of the ionized intracluster medium, indicative of a collapsed and nearly virialized system, is made challenging by the high redshifts of the sample members. The main goal of this work is to test the capabilities of the Atacama Compact Array (ACA; also known as the Morita Array) Band 3 observations, centered at about 97.5 GHz, to provide robust validation of cluster detections via the thermal Sunyaev-Zeldovich (SZ) effect. Using a pilot sample that comprises ten MaDCoWS galaxy clusters, accessible to ACA and representative of the median sample richness, we infer the masses of the selected galaxy clusters and respective detection significance by means of a Bayesian analysis of the interferometric data. Our test of the "Verification with the ACA - Localization and Cluster Analysis" (VACA LoCA) program demonstrates that the ACA can robustly confirm the presence of the virialized intracluster medium in galaxy clusters previously identified in full-sky surveys. In particular, we obtain a significant detection of the SZ effect for seven out of the ten VACA LoCA clusters. We note that this result is independent of the assumed pressure profile. However, the limited angular dynamic range of the ACA in Band 3 alone, short observational integration times, and possible contamination from unresolved sources limit the detailed characterization of the cluster properties and the inference of the cluster masses within scales appropriate for the robust calibration of mass-richness scaling relations.

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arXiv2020

The CatWISE Preliminary Catalog: Motions from ${\it WISE}$ and ${\it NEOWISE}$ Data

CatWISE is a program to catalog sources selected from combined ${\it WISE}$ and ${\it NEOWISE}$ all-sky survey data at 3.4 and 4.6 $μ$m (W1 and W2). The CatWISE Preliminary Catalog consists of 900,849,014 sources measured in data collected from 2010 to 2016. This dataset represents four times as many exposures and spans over ten times as large a time baseline as that used for the AllWISE Catalog. CatWISE adapts AllWISE software to measure the sources in coadded images created from six-month subsets of these data, each representing one coverage of the inertial sky, or epoch. The catalog includes the measured motion of sources in 8 epochs over the 6.5 year span of the data. From comparison to ${\it Spitzer}$, the SNR=5 limits in magnitudes in the Vega system are W1=17.67 and W2=16.47, compared to W1=16.96 and W2=16.02 for AllWISE. From comparison to ${\it Gaia}$, CatWISE positions have typical accuracies of 50 mas for stars at W1=10 mag and 275 mas for stars at W1=15.5 mag. Proper motions have typical accuracies of 10 mas yr$^{-1}$ and 30 mas yr$^{-1}$ for stars with these brightnesses, an order of magnitude better than from AllWISE. The catalog is available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive.

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arXiv2019

Improved infrared photometry and a preliminary parallax measurement for the extremely cold brown dwarf CWISEP J144606.62$-$231717.8

We present follow-up $Spitzer$ observations at 3.6$μ$m (ch1) and 4.5$μ$m (ch2) of CWISEP J144606.62$-$231717.8, one of the coldest known brown dwarfs in the solar neighborhood. This object was found by mining the Wide-field Infrared Survey Explorer ($WISE$) and $NEOWISE$ data via the CatWISE Preliminary Catalog by Meisner et al. (2019b), where an initial $Spitzer$ color of ch1$-$ch2 = 3.71$\pm$0.44 mag was reported, implying it could be one of the reddest, and hence coldest, known brown dwarfs. Additional $Spitzer$ data presented here allows us to revise its color to ch1$-$ch2 = 2.986$\pm$0.048 mag, which makes CWISEP J144606.62$-$231717.8 the 5th reddest brown dwarf ever observed. A preliminary trigonometric parallax measurement, based on a combination of $WISE$ and $Spitzer$ astrometry, places this object at a distance of 10.1$^{+1.7}_{-1.3}$ pc. Based on our improved $Spitzer$ color and preliminary parallax, CWISEP J144606.62$-$231717.8 has a $T_{\rm eff}$ in the 310$-$360 K range. Assuming an age of 0.5$-$13 Gyr, this corresponds to a mass between 2 and 20 $M_{\rm Jup}$.

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arXiv2019

Expanding the Y Dwarf Census with Spitzer Follow-up of the Coldest CatWISE Solar Neighborhood Discoveries

We present Spitzer 3.6$μ$m and 4.5$μ$m follow-up of 170 candidate extremely cool brown dwarfs newly discovered via the combination of WISE and NEOWISE imaging at 3$-$5$μ$m. CatWISE, a joint analysis of archival WISE and NEOWISE data, has improved upon the motion measurements of AllWISE by leveraging a $>$10$\times$ time baseline enhancement, from 0.5 years (AllWISE) to 6.5 years (CatWISE). As a result, CatWISE motion selection has yielded a large sample of previously unrecognized brown dwarf candidates, many of which have archival detections exclusively in the WISE 4.6$μ$m (W2) channel, suggesting that they could be both exceptionally cold and nearby. Where these objects go undetected in WISE W1 (3.4$μ$m), Spitzer can provide critically informative detections at 3.6$μ$m. Of our motion-confirmed discoveries, seventeen have a best-fit Spitzer [3.6]$-$[4.5] color most consistent with spectral type Y. CWISEP J144606.62$-$231717.8 ($μ\approx 1.3''$/yr) is likely the reddest, and therefore potentially coldest, member of our sample with a very uncertain [3.6]$-$[4.5] color of 3.71 $\pm$ 0.44 magnitudes. We also highlight our highest proper motion discovery, WISEA J153429.75$-$104303.3, with $μ\approx 2.7''$/yr. Given that the prior list of confirmed and presumed Y dwarfs consists of just 27 objects, the Spitzer follow-up presented in this work has substantially expanded the sample of identified Y dwarfs. Our new discoveries thus represent significant progress toward understanding the bottom of the substellar mass function, investigating the diversity of the Y dwarf population, and selecting optimal brown dwarf targets for JWST spectroscopy.

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arXiv2019

The Massive and Distant Clusters of WISE Survey VII: The Environments and Properties of Radio Galaxies in Clusters at z~1

We present the results from a study with NSF's Karl G. Jansky Very Large Array (VLA) to determine the radio morphologies of extended radio sources and the properties of their host galaxies in 50 massive galaxy clusters at z~1. We find a majority of the radio morphologies to be Fanaroff-Riley (FR) type IIs. By analyzing the infrared counterparts of the radio sources, we find that ~40% of the host galaxies are the candidate brightest cluster galaxy (BCG) and ~83% are consistent with being one of the top six most massive galaxies in the cluster. We investigate the role of environmental factors on the radio-loud AGN population by examining correlations between environmental and radio-galaxy properties. We find that the highest stellar mass hosts ($M_{*} \gtrsim$ 4$\times 10^{11} M_{\odot}$) are confined to the cluster center and host compact jets. There is evidence for an increase in the size of the jets with cluster-centric radius, which may be attributed to the decreased ICM pressure confinement with increasing radius. Besides this correlation, there are no other significant correlations between the properties of the radio-AGN (luminosity, morphology, or size) and environmental properties (cluster richness and location within the cluster). The fact that there are more AGN in the cluster environment than the field at this epoch, combined with the lack of strong correlation between galaxy and environmental properties, argues that the cluster environment fosters radio activity but does not solely drive the evolution of these sources at this redshift.

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arXiv2019

CWISEP J193518.59$-$154620.3: An Extremely Cold Brown Dwarf in the Solar Neighborhood Discovered with CatWISE

We present the discovery of an extremely cold, nearby brown dwarf in the solar neighborhood, found in the CatWISE catalog (Eisenhardt et al., in prep.). Photometric follow-up with Spitzer reveals that the object, CWISEP J193518.59-154620.3, has ch1$-$ch2 = 3.24$\,\pm\,$0.31 mag, making it one of the reddest brown dwarfs known. Using the Spitzer photometry and the polynomial relations from Kirkpatrick et al. (2019) we estimate an effective temperature in the $\sim$270--360 K range, and a distance estimate in the 5.6$-$10.9 pc range. We combined the WISE, NEOWISE, and Spitzer data to measure a proper motion of $μ_α\cos δ= 337\pm69$ mas yr$^{-1}$, $μ_δ= -50\pm97$ mas yr$^{-1}$, which implies a relatively low tangential velocity in the range 7$-$22 km s$^{-1}$.

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arXiv2019

The Massive and Distant Clusters of WISE Survey VI: Stellar Mass Fractions of a Sample of High-Redshift Infrared-selected Clusters

We present measurements of the stellar mass fractions ($f_\star$) for a sample of high-redshift ($0.93 \le z \le 1.32$) infrared-selected galaxy clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) and compare them to the stellar mass fractions of Sunyaev-Zel'dovich (SZ) effect-selected clusters in a similar mass and redshift range from the South Pole Telescope (SPT)-SZ Survey. We do not find a significant difference in mean $f_\star$ between the two selection methods, though we do find an unexpectedly large range in $f_\star$ for the SZ-selected clusters. In addition, we measure the luminosity function of the MaDCoWS clusters and find $m^*= 19.41\pm0.07$, similar to other studies of clusters at or near our redshift range. Finally, we present SZ detections and masses for seven MaDCoWS clusters and new spectroscopic redshifts for five MaDCoWS clusters. One of these new clusters, MOO J1521+0452 at $z=1.31$, is the most distant MaDCoWS cluster confirmed to date.

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arXiv2018

The Massive and Distant Clusters of WISE Survey. I: Survey Overview and a Catalog of >2000 Galaxy Clusters at z~1

We present the Massive and Distant Clusters of WISE Survey (MaDCoWS), a search for galaxy clusters at 0.7 -30 degrees) and the remainder of the southern extragalactic sky at Dec<-30 degrees for which shallower optical data from SuperCOSMOS Sky Survey are available. In this paper we describe the search algorithm, characterize the sample, and present the first MaDCoWS data release -- catalogs of the 2433 highest amplitude detections in the WISE--Pan-STARRS region and the 250 highest amplitude detections in the WISE--SuperCOSMOS region. A total of 1723 of the detections from the WISE--Pan-STARRS sample have also been observed with the Spitzer Space Telescope, providing photometric redshifts and richnesses, and an additional 64 detections within the WISE--SuperCOSMOS region also have photometric redshifts and richnesses. Spectroscopic redshifts for 38 MaDCoWS clusters with IRAC photometry demonstrate that the photometric redshifts have an uncertainty of $σ_z/(1+z)\sim0.036$. Combining the richness measurements with Sunyaev-Zel'dovich observations of MaDCoWS clusters, we also present a preliminary mass-richness relation that can be used to infer the approximate mass distribution of the full sample. The estimated median mass for the WISE--Pan-STARRS catalog is $M_{500}=1.6^{+0.7}_{-0.8}\times10^{14} \mathrm{M}_\odot$, with the Sunyaev-Zel'dovich data confirming that we detect clusters with masses up to $M_{500}\sim5\times10^{14} \mathrm{M}_\odot$ $(M_{200}\sim10^{15} \mathrm{M}_\odot)$.

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arXiv2018

The Massive and Distant Clusters of WISE Survey V: Extended Radio Sources in Massive Galaxy Clusters at z~1

We present the results from a pilot study with the Karl G. Jansky Very Large Array (JVLA) to determine the radio morphologies of extended radio sources and the properties of their host-galaxies in 10 massive galaxy clusters at z~1, an epoch in which clusters are assembling rapidly. These clusters are drawn from a parent sample of WISE-selected galaxy clusters that were cross-correlated with the VLA Faint Images of the Radio Sky at Twenty-Centimeters survey (FIRST) to identify extended radio sources within 1$^{\prime}$ of the cluster centers. Out of the ten targeted sources, six are FR II sources, one is an FR I source, and three sources have undetermined morphologies. Eight radio sources have associated Spitzer data, 75% presenting infrared counterparts. A majority of these counterparts are consistent with being massive galaxies. The angular extent of the FR sources exhibits a strong correlation with the cluster-centric radius, which warrants further investigation with a larger sample.

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arXiv2017

Eddington-Limited Accretion in z~2 WISE-selected Hot, Dust-Obscured Galaxies

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 Hot DOGs (~ 10^{9} M_sun), and their derived Eddington ratios are close to unity. These z~2 Hot DOGs are the most luminous AGNs at given BH masses, suggesting they are accreting at the maximum rates for their BHs. A similar property is found for known z~6 quasars. Our results are consistent with scenarios in which Hot DOGs represent a transitional, high-accretion phase between obscured and unobscured quasars. Hot DOGs may mark a special evolutionary stage before the red quasar and optical quasar phases, and they may be present at other cosmic epochs.

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arXiv2016

The AllWISE Motion Survey, Part 2

We use the AllWISE Data Release to continue our search for WISE-detected motions. In this paper, we publish another 27,846 motion objects, bringing the total number to 48,000 when objects found during our original AllWISE motion survey are included. We use this list, along with the lists of confirmed WISE-based motion objects from the recent papers by Luhman and by Schneider et al. and candidate motion objects from the recent paper by Gagne et al. to search for widely separated, common-proper-motion systems. We identify 1,039 such candidate systems. All 48,000 objects are further analyzed using color-color and color-mag plots to provide possible characterizations prior to spectroscopic follow-up. We present spectra of 172 of these, supplemented with new spectra of 23 comparison objects from the literature, and provide classifications and physical interpretations of interesting sources. Highlights include: (1) the identification of three G/K dwarfs that can be used as standard candles to study clumpiness and grain size in nearby molecular clouds because these objects are currently moving behind the clouds, (2) the confirmation/discovery of several M, L, and T dwarfs and one white dwarf whose spectrophotometric distance estimates place them 5-20 pc from the Sun, (3) the suggestion that the Na 'D' line be used as a diagnostic tool for interpreting and classifying metal-poor late-M and L dwarfs, (4) the recognition of a triple system including a carbon dwarf and late-M subdwarf, for which model fits of the late-M subdwarf (giving [Fe/H] ~ -1.0) provide a measured metallicity for the carbon star, and (5) a possible 24-pc-distant K5 dwarf + peculiar red L5 system with an apparent physical separation of 0.1 pc.

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