- ID:
- ivo://CDS.VizieR/J/ApJ/791/113
- Title:
- MIR-selected quasar parameters
- Short Name:
- J/ApJ/791/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide a catalog of 391 mid-infrared-selected (MIR; 24 {mu}m) broad-emission-line (BEL; type 1) quasars in the 22 deg^2^ SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S_24_> 400 {mu}Jy, jointly with an optical magnitude limit of r(AB) < 22.5 for broad line identification. The catalog is based on MMT and Sloan Digital Sky Survey (SDSS) spectroscopy to select BEL quasars, extending the SDSS coverage to fainter magnitudes and lower redshifts, and recovers a more complete quasar population. The MIR-selected quasar sample peaks at z ~ 1.4 and recovers a significant and constant (20%) fraction of extended objects with SDSS photometry across magnitudes, which were not included in the SDSS quasar survey dominated by point sources. This sample also recovers a significant population of z < 3 quasars at i > 19.1. We then investigate the continuum luminosity and line profiles of these MIR quasars, and estimate their virial black hole masses and the Eddington ratios. The supermassive black hole mass shows evidence of downsizing, although the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra are publicly available online.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/701/1123
- Title:
- MIR spectroscopic catalog of 150 galaxies
- Short Name:
- J/ApJ/701/1123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of mid-infrared (MIR) spectra of 150 infrared (IR) luminous galaxies in the Spitzer extragalactic first look survey obtained with the IR spectrograph on board the Spitzer Space Telescope. The sample is selected to be brighter than ~0.9mJy at 24um and it has a redshift distribution in the range [0.3, 3.5], with a peak at z=1. It primarily comprises ultraluminous IR galaxies (ULIRGs) at z>~1 and luminous IR galaxies at z<1, as estimated from their monochromatic rest-frame 14um luminosities. The number of sources with spectra that are dominated by an active galactic nucleus (AGN) continuum is 49, while 39 sources have strong, star formation related features.
- ID:
- ivo://CDS.VizieR/J/ApJS/229/20
- Title:
- MMT/Hectospec redshift survey for Abell 2029
- Short Name:
- J/ApJS/229/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on an extensive redshift survey for galaxy clusters Abell 2029 and Coma, we measure the luminosity functions (LFs) and stellar mass functions (SMFs) for the entire cluster member galaxies. Most importantly, we measure the velocity dispersion functions (VDFs) for quiescent members. The MMT/Hectospec redshift survey for galaxies in A2029 identifies 982 spectroscopic members; for 838 members, we derive the central velocity dispersion from the spectroscopy. Coma is the only other cluster surveyed as densely. The LFs, SMFs, and VDFs for A2029 and Coma are essentially identical. The SMFs of the clusters are consistent with simulations. The A2029 and Coma VDFs for quiescent galaxies have a significantly steeper slope than those of field galaxies for velocity dispersion 100km/s. The cluster VDFs also exceed the field at velocity dispersion 250km/s. The differences between cluster and field VDFs are potentially important tests of simulations and of the formation of structure in the universe.
- ID:
- ivo://CDS.VizieR/J/ApJ/903/151
- Title:
- MMT spectroscopic redshift catalog of the A521 field
- Short Name:
- J/ApJ/903/151
- Date:
- 21 Mar 2022 05:59:04
- Publisher:
- CDS
- Description:
- A521 has been a subject of extensive panchromatic studies from X-ray to radio. The cluster possesses a number of remarkable features, including a bright radio relic with a steep spectrum, more than three distinct galaxy groups forming a filament, and two disturbed X-ray peaks at odds with the distant position and tilted orientation of the radio relic. These lines of evidence indicate a complex merger. In this paper, we present a multiwavelength study of A521 based on Subaru optical, Hubble Space Telescope infrared, Chandra X-ray, Giant Metrewave Radio Telescope radio, and Multiple Mirror Telescope optical spectroscopic observations. Our weak-lensing (WL) analysis with improved systematics control reveals that A521 is mainly composed of three substructures aligned in the northwest to southeast orientation. These WL mass substructures are remarkably well-aligned with the cluster optical luminosity distribution constructed from our new enhanced cluster member catalog. These individual substructure masses are determined by simultaneously fitting three Navarro-Frenk-White profiles. We find that the total mass of A521 modeled by the superposition of the three halos is 13.0_-1.3_^+1.0^x10^14^M{odot}, a factor of 2 higher than the previous WL measurement. With these WL mass constraints combined with X-ray and radio features, we consider two merging scenarios, carry out the corresponding numerical simulations, and discuss the strengths and weaknesses of each case.
- ID:
- ivo://CDS.VizieR/J/ApJ/849/L36
- Title:
- mm-wave size study of ALMA submm galaxies
- Short Name:
- J/ApJ/849/L36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the study of the far-infrared (IR) sizes of submillimeter galaxies (SMGs) in relation to their dust-obscured star formation rate (SFR) and active galactic nuclei (AGN) presence, determined using mid-IR photometry. We determined the millimeter-wave ({lambda}_obs_=1100um) sizes of 69 Atacama Large Millimeter/submillimeter Array (ALMA)-identified SMGs, selected with >=10{sigma} confidence on ALMA images (F_1100um_=1.7-7.4mJy). We found that all of the SMGs are located above an avoidance region in the size-flux plane, as expected by the Eddington limit for star formation. In order to understand what drives the different millimeter-wave sizes in SMGs, we investigated the relation between millimeter-wave size and AGN fraction for 25 of our SMGs at z=1-3. We found that the SMGs for which the mid-IR emission is dominated by star formation or AGN have extended millimeter-sizes, with respective median R_c,e_=1.6_-0.21_^+0.34^ and 1.5_-0.24_^+0.93^kpc. Instead, the SMGs for which the mid-IR emission corresponds to star-forming/AGN composites have more compact millimeter-wave sizes, with median R_c,e_=1.0_-0.20_^+0.20^kpc. The relation between millimeter-wave size and AGN fraction suggests that this size may be related to the evolutionary stage of the SMG. The very compact sizes for composite star-forming/AGN systems could be explained by supermassive black holes growing rapidly during the SMG coalescing, star-formation phase.
- ID:
- ivo://CDS.VizieR/J/ApJ/732/65
- Title:
- Modeling the local velocity field with SNIa
- Short Name:
- J/ApJ/732/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We apply statistically rigorous methods of nonparametric risk estimation to the problem of inferring the local peculiar velocity field from nearby Type Ia supernovae (SNIa). We use two nonparametric methods -weighted least squares (WLS) and coefficient unbiased (CU)- both of which employ spherical harmonics to model the field and use the estimated risk to determine at which multipole to truncate the series. We show that if the data are not drawn from a uniform distribution or if there is power beyond the maximum multipole in the regression, a bias is introduced on the coefficients using WLS. CU estimates the coefficients without this bias by including the sampling density making the coefficients more accurate but not necessarily modeling the velocity field more accurately. After applying nonparametric risk estimation to SNIa data, we find that there are not enough data at this time to measure power beyond the dipole. The WLS Local Group bulk flow is moving at 538+/-86km/s toward (l,b)=(258+/-10{deg},36+/-11{deg}) and the CU bulk flow is moving at 446+/-101km/s toward (l,b)=(273+/-11{deg},46+/-8{deg}). We find that the magnitude and direction of these measurements are in agreement with each other and previous results in the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/802/103
- Title:
- Model predictions for GRB host galaxies
- Short Name:
- J/ApJ/802/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Long-duration gamma-ray bursts (GRBs) are powerful probes of the star formation history of the universe, but the correlation between the two depends on the highly debated presence and strength of a metallicity bias. To investigate this correlation, we use a phenomenological model that successfully describes star formation rates, luminosities, and stellar masses of star-forming galaxies and apply it to GRB production. We predict the luminosities, stellar masses, and metallicities of host galaxies depending on the presence (or absence) of a metallicity bias. Our best-fitting model includes a moderate metallicity bias, broadly consistent with the large majority of the long-duration GRBs in metal-poor environments originating from a collapsar (probability ~83%, with [0.74;0.91] range at 90% confidence level), but with a secondary contribution (~17%) from a metal-independent production channel, such as binary evolution. Because of the mass-metallicity relation of galaxies, the maximum likelihood model predicts that the metal-independent channel becomes dominant at z~<2, where hosts have higher metallicities and collapsars are suppressed. This possibly explains why some studies find no clear evidence of a metal bias based on low-z samples. However, while metallicity predictions match observations well at high redshift (z>~2), there is tension with low-redshift observations, since a significant fraction of GRB hosts are predicted to have (near) solar metallicity. This is in contrast to observations, unless obscured, metal-rich hosts are preferentially missed in current data sets, and suggests that lower efficiencies of the metal-independent GRB channel might be preferred following a comprehensive fit that includes metallicity of GRB hosts from complete samples. Overall, we are able to clearly establish the presence of a metallicity bias for GRB production, but continued characterization of GRB host galaxies is needed to quantify its strength.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/5104
- Title:
- Model selection with strong-lensing systems
- Short Name:
- J/MNRAS/478/5104
- Date:
- 10 Dec 2021 13:55:35
- Publisher:
- CDS
- Description:
- In this paper, we use an unprecedentedly large sample (158) of confirmed strong lens systems for model selection, comparing five well-studied Friedmann-Robertson-Walker cosmologies: {Lambda}CDM, wCDM (the standard model with a variable dark-energy equation of state), the R_h_=ct universe, the (empty) Milne cosmology, and the classical Einstein-de Sitter (matter-dominated) universe. We first use these sources to optimize the parameters in the standard model and show that they are consistent with Planck, though the quality of the best fit is not satisfactory. We demonstrate that this is likely due to underreported errors, or to errors yet to be included in this kind of analysis. We suggest that the missing dispersion may be due to scatter about a pure single isothermal sphere (SIS) model that is often assumed for the mass distribution in these lenses. We then use the Bayes information criterion, with the inclusion of a suggested SIS dispersion, to calculate the relative likelihoods and ranking of these models, showing that Milne and Einstein-de Sitter are completely ruled out, while R_h_=ct is preferred over {Lambda}CDM/wCDM with a relative probability of ~73 percent versus ~24 percent. The recently reported sample of new strong lens candidates by the Dark Energy Survey, if confirmed, may be able to demonstrate which of these two models is favoured over the other at a level exceeding 3{sigma}.
- ID:
- ivo://CDS.VizieR/J/ApJ/690/20
- Title:
- Models of the AGN and black hole populations
- Short Name:
- J/ApJ/690/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We construct evolutionary models of the populations of active galactic nuclei (AGNs) and supermassive black holes, in which the black hole mass function grows at the rate implied by the observed luminosity function, given assumptions about the radiative efficiency and the luminosity in Eddington units. We draw on a variety of recent X-ray and optical measurements to estimate the bolometric AGN luminosity function and compare to X-ray background data and the independent estimate of Hopkins et al. to assess remaining systematic uncertainties. The integrated AGN emissivity closely tracks the cosmic star-formation history, suggesting that star formation and black hole growth are closely linked at all redshifts.
- ID:
- ivo://CDS.VizieR/J/AJ/144/105
- Title:
- MOJAVE. VIII. Faraday rotation in AGN jets.
- Short Name:
- J/AJ/144/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of Faraday rotation measures for a sample of 191 extragalactic radio jets observed within the MOJAVE program. Multifrequency Very Long Baseline Array observations were carried out over 12 epochs in 2006 at four frequencies between 8 and 15GHz. We detect parsec-scale Faraday rotation measures in 149 sources and find the quasars to have larger rotation measures on average than BL Lac objects. The median core rotation measures are significantly higher than in the jet components. This is especially true for quasars where we detect a significant negative correlation between the magnitude of the rotation measure and the de-projected distance from the core. We perform detailed simulations of the observational errors of total intensity, polarization, and Faraday rotation, and concentrate on the errors of transverse Faraday rotation measure gradients in unresolved jets. Our simulations show that the finite image restoring beam size has a significant effect on the observed rotation measure gradients, and spurious gradients can occur due to noise in the data if the jet is less than two beams wide in polarization. We detect significant transverse rotation measure gradients in four sources (0923+392, 1226+023, 2230+114, and 2251+158). In 1226+023 the rotation measure is for the first time seen to change sign from positive to negative over the transverse cuts, which supports the presence of a helical magnetic field in the jet. In this source we also detect variations in the jet rotation measure over a timescale of three months, which are difficult to explain with external Faraday screens and suggest internal Faraday rotation. By comparing fractional polarization changes in jet components between the four frequency bands to depolarization models, we find that an external purely random Faraday screen viewed through only a few lines of sight can explain most of our polarization observations, but in some sources, such as 1226+023 and 2251+158, internal Faraday rotation is needed.
