- ID:
- ivo://CDS.VizieR/J/AJ/122/503
- Title:
- SDSS u*g*r*i*z* photometry and redshift of QSOs
- Short Name:
- J/AJ/122/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present data for over 100 high-redshift quasars found in ~700deg^2^ by the Sloan Digital Sky Survey (SDSS), using automated selection algorithms applied to SDSS imaging data and with spectroscopic confirmation obtained during routine spectroscopic observations by the Sloan 2.5 m telescope. The SDSS spectra cover the wavelength range 3900-9200{AA}E at a spectral resolution of 1800 and have been obtained for 116 quasars with redshifts greater than 3.94; 92 of these objects were previously uncatalogued, significantly increasing the current list of published z>4 quasars. The paper also reports observations of seven additional new z>4 quasars; all were selected from the SDSS imaging survey and spectroscopically confirmed with observations by the Apache Point Observatory's 3.5 m telescope or the Hobby-Eberly Telescope.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/793/108
- Title:
- SEAMBHs. II. Continuum and Hbeta LCs
- Short Name:
- J/ApJ/793/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second in a series of papers reporting on a large reverberation mapping (RM) campaign to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). The goal is to identify super-Eddington accreting massive black holes (SEAMBHs) and to use their unique properties to construct a new method for measuring cosmological distances. Based on theoretical models, the saturated bolometric luminosity of such sources is proportional to the BH mass, which can be used to obtain their distance. Here we report on five new RM measurements and show that in four of the cases, we can measure the BH mass and three of these sources are SEAMBHs. Together with the three sources from our earlier work, we now have six new sources of this type. We use a novel method based on a minimal radiation efficiency to identify nine additional SEAMBHs from earlier RM-based mass measurements. We use a Bayesian analysis to determine the parameters of the new distance expression and the method uncertainties from the observed properties of the objects in the sample. The ratio of the newly measured distances to the standard cosmological ones has a mean scatter of 0.14 dex, indicating that SEAMBHs can be use as cosmological distance probes. With their high luminosity, long period of activity, and large numbers at high redshifts, SEAMBHs have a potential to extend the cosmic distance ladder beyond the range now explored by Type Ia supernovae.
- ID:
- ivo://CDS.VizieR/J/ApJ/825/126
- Title:
- SEAMBHs. V. The third year
- Short Name:
- J/ApJ/825/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports results of the third-year campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs) between 2014 and 2015. Ten new targets were selected from the quasar sample of the Sloan Digital Sky Survey (SDSS), which have generally been more luminous than the SEAMBH candidates in the last two years. H{beta} lags ({tau}_H{beta}_) in five of the 10 quasars have been successfully measured in this monitoring season. We find that the lags are generally shorter, by large factors, than those of objects with same optical luminosity, in light of the well-known R_H{beta}_-L_5100_ relation. The five quasars have dimensionless accretion rates of dM/dt=10-10^3^. Combining these with measurements of the previous SEAMBHs, we find that the reduction of H{beta} lags depends tightly on accretion rates, {tau}_H{beta}_/{tau}_R-L_{propto}(dM/dt)^-0.42^, where {tau}_R-L_ is the H{beta} lag from the normal R_H{beta}_-L_5100_ relation. Fitting 63 mapped AGNs, we present a new scaling relation for the broad-line region: R_H{beta}_={alpha}_1_l_44_^{beta}1^min [1,(dM/dt)/(dM/dt)_c_)^-{gamma}1^], where l_44_=L_5100_/10^44^erg/s is the 5100{AA} continuum luminosity, and the coefficients are {alpha}_1_=29.6_-2.8_^+2.7^ lt-day, {beta}1=0.56_-0.03_^+0.03^, {gamma}1=0.52_-0.16_^+0.33^, and (dM/dt)_c_=11.19_-6.22_^+2.29^. This relation is applicable to AGNs over a wide range of accretion rates, from 10^-3^ to 10^3^. Implications of this new relation are briefly discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/20
- Title:
- SEAMBHs XII. Reberberation mapping for 15 PG QSOs
- Short Name:
- J/ApJS/253/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present the first results of the long-term high-cadence spectroscopic monitoring of 15 PG quasars with relatively strong FeII emission, as a part of a broader reverberation mapping campaign performed using the Calar Alto Observatory's 2.2m telescope. The V-band, 5100{AA} continuum, and H{beta} broad emission line light curves are measured for a set of quasars for periods ranging from dozens to more than a hundred epochs between 2017 May and 2020 July. Accurate time lags between the variations of the H{beta} broad-line fluxes and the optical continuum strength are obtained for all 15 quasars, ranging from 17.0_-3.2_^+2.5^ to 95.9_-23.9_^+7.1^ days in the rest frame. The virial masses of the central supermassive black holes are derived for all 15 quasars, ranging between 0.50_-0.19_^+0.18^ and 19.17_-2.73_^+2.98^ in units of 10^7^M_{sun}_. For 11 of the objects in our sample, this is the first reverberation analysis to be published. Of the rest, two objects have been the subject of previous reverberation studies, but we determine time lags for these that are only half as long as those found in the earlier investigations, which had only been able to sample much more sparsely. The remaining two objects have previously been monitored with high sampling rates. Our results here are consistent with the earlier findings, in the sense that the time lag and the line width vary inversely, consistent with virialization.
- ID:
- ivo://CDS.VizieR/J/ApJ/877/23
- Title:
- SEAMBHs. X. Reverberation mapping campaign compilation
- Short Name:
- J/ApJ/877/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns, including our ongoing campaign of monitoring super-Eddington accreting massive black holes (BHs). This sample covers a large range of BH mass (M_{bullet}_=10^6^-9^M_{sun}_), dimensionless accretion rates (dM/dt=10^-2.7^-10^2.7^), and 5100{AA} luminosity (L_5100_=10^42-46^erg/s), allowing us to systematically study the AGN variability and their relations with BH mass, accretion rates, and optical luminosity. We employed the damped random walk (DRW) model to delineate the optical variability of continuum at 5100{AA} and obtained damped variability timescale ({tau}_d_) and amplitude ({sigma}_d_) using a Markov Chain Monte Carlo method. We also estimated the traditional variability amplitudes (F_var_), which provide a model-independent measure and therefore are used to test the DRW results. We found that AGN variability characteristics are generally correlated with (M_{bullet}_, dM/dt, L_5100_). These correlations are smooth from sub-Eddington to super-Eddington accretion AGNs, probably implying that the AGN variability may be caused by the same physical mechanism.
1166. Second CIZA subsample
- ID:
- ivo://CDS.VizieR/J/ApJ/662/224
- Title:
- Second CIZA subsample
- Short Name:
- J/ApJ/662/224
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the latest results of the Clusters in the Zone of Avoidance (CIZA) survey, which is mapping large-scale structures behind the Milky Way by performing the first systematic search for galaxy clusters at low Galactic latitudes. The survey's approach, which uses X-ray emission to locate cluster candidates, minimizes the problems faced by optically selected cluster surveys, which have traditionally avoided this region of the sky due to the severe extinction present along the Galactic plane. We here present the second flux-limited CIZA cluster catalog, containing 57 X-ray-selected galaxy clusters, of which 88% are new discoveries. We use this sample to examine the degree to which known large-scale structures extend into the zone of avoidance and highlight newly discovered structures that have previously gone unnoticed.
- ID:
- ivo://CDS.VizieR/J/ApJ/786/59
- Title:
- SED fitting results of HETDEX pilot survey
- Short Name:
- J/ApJ/786/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use broadband photometry extending from the rest-frame UV to the near-IR to fit the individual spectral energy distributions of 63 bright (L(Ly{alpha})>10^43^ erg/s) Ly{alpha} emitting galaxies (LAEs) in the redshift range 1.9<z<3.6. We find that these LAEs are quite heterogeneous, with stellar masses that span over three orders of magnitude, from 7.5<log M/M_{sun}_<10.5. Moreover, although most LAEs have small amounts of extinction, some high-mass objects have stellar reddenings as large as E(B-V)~0.4. Interestingly, in dusty objects the optical depths for Ly{alpha} and the UV continuum are always similar, indicating that Ly{alpha} photons are not undergoing many scatters before escaping their galaxy. In contrast, the ratio of optical depths in low-reddening systems can vary widely, illustrating the diverse nature of the systems. Finally, we show that in the star-formation-rate-log-mass diagram, our LAEs fall above the "main-sequence" defined by z~3 continuum selected star-forming galaxies. In this respect, they are similar to submillimeter-selected galaxies, although most LAEs have much lower mass.
- ID:
- ivo://CDS.VizieR/J/AJ/143/125
- Title:
- SED of 113 dust-obscured galaxies at z~2
- Short Name:
- J/AJ/143/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust-obscured galaxies (DOGs) are a subset of high-redshift (z~2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L_IR_>10^12^L_{sun}_). We present new far-infrared photometry, at 250, 350, and 500{mu}m (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10^11.6^L_{sun}_<L_IR_(8-1000{mu}m)<10^13.6^L_{sun}_. 90% of the Herschel-detected DOGs in this sample are ULIRGs and 30% have L_IR_>10^13L{sun}. The rest-frame near-IR (1-3{mu}m) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/81
- Title:
- SED of hard X-ray selected AGN in XMDS
- Short Name:
- J/ApJ/663/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the SEDs of a hard X-ray selected sample containing 136 sources with F(2-10)keV>10^-14^erg/cm^2^/s; 132 are AGNs. The sources are detected in a 1deg^2^ area of the XMM-Newton Medium Deep Survey where optical data from the VVDS and CFHTLS and infrared data from the SWIRE survey are available. Based on a SED fitting technique we derive photometric redshifts with {sigma}(1+z)=0.11 and 6% of outliers and identify AGN signatures in 83% of the objects. This fraction is higher than derived when a spectroscopic classification is available. The remaining 17% of AGNs show star-forming galaxy SEDs (SF class).
- ID:
- ivo://CDS.VizieR/J/ApJ/684/136
- Title:
- SEDs of ELAIS-S1 mid-IR sources
- Short Name:
- J/ApJ/684/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the broadband SEDs of the largest available highly complete (72%) spectroscopic sample of MIR-selected galaxies and AGNs at intermediate redshift. The sample contains 203 extragalactic sources from the 15um ELAIS-SWIRE survey, all with measured spectroscopic redshift. Most of these sources have full multiwavelength coverage from the FUV (GALEX) to the FIR (Spitzer) and lie in the redshift range 0.1<z<1.3. This large sample allows us for the first time to characterize the spectral properties of sources responsible for the strong evolution observed in the MIR. Based on SED-fitting, we have classified the MIR sources, identifying AGN signatures in about 50% of them. This fraction is significantly higher than that derived from optical spectroscopy (~29%) and is due in particular to the identification of AGN activity in objects spectroscopically classified as galaxies (the spectroscopic classification may be somewhat unreliable because of host galaxy dilution in the optical). It is likely that in most of our objects, the AGN is either obscured or low luminosity, and thus dominates the energetic output only in the MIR, showing up just in the range where the host galaxy SED has a minimum. The fraction of AGNs strongly depends on flux density, with that derived through the SED-fitting about 20% at S_15um_~0.5-1mJy and gradually increasing to 100% at S_15um_>10mJy, while that obtained from optical spectroscopy is never >30%, even at higher flux densities.