- ID:
- ivo://CDS.VizieR/J/ApJ/798/54
- Title:
- "Under-massive" black hole candidates
- Short Name:
- J/ApJ/798/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several recent papers have reported on the occurrence of active galactic nuclei (AGNs) containing undermassive black holes relative to a linear scaling relation between black hole mass (M_bh_) and host spheroid stellar mass (M_sph,*_). However, dramatic revisions to the M_bh_-M_sph,*_ and M_bh_-L_sph_ relations, based on samples containing predominantly inactive galaxies, have recently identified a new steeper relation at M_bh_<~(2-10)x10^8^M_{sun}_, roughly corresponding to M_sph,*_<~(0.3-1)x10^11^M_{sun}_. We show that this steeper, quadratic-like M_bh_-M_sph,*_ relation defined by the Sersic galaxies, i.e., galaxies without partially depleted cores, roughly tracks the apparent offset of the AGN having 10^5^<~M_bh_/M_{sun}_<~0.5x10^8^. That is, these AGNs are not randomly offset with low black hole masses, but also follow a steeper (nonlinear) relation. As noted by Busch et al. (2014, J/A+A/561/A140), confirmation or rejection of a possible AGN offset from the steeper M_bh_-M _sph,*_ relation defined by the Sersic galaxies will benefit from improved stellar mass-to-light ratios for the spheroids hosting these AGNs. Several implications for formation theories are noted. Furthermore, reasons for possible under- and overmassive black holes, the potential existence of intermediate mass black holes (<10^5^M_{sun}_), and the new steep (black hole)-(nuclear star cluster) relation, M_bh_{propto}M_nc_^2.7+/-0.7^, are also discussed.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/869/56
- Title:
- Updated calibration of the CSP-I SNe Ia sample
- Short Name:
- J/ApJ/869/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the final data release of the Carnegie Supernova Project I (CSP-I; Krisciunas+ 2017, J/AJ/154/211), focusing on the absolute calibration of the luminosity-decline rate relation for Type Ia supernovae (SNe Ia) using new intrinsic color relations with respect to the color-stretch parameter, s_BV_, enabling improved dust extinction corrections. We investigate to what degree the so-called fast-declining SNe Ia can be used to determine accurate extragalactic distances. We estimate the intrinsic scatter in the luminosity-decline rate relation and find it ranges from +/-0.13mag to +/-0.18mag with no obvious dependence on wavelength. Using the Cepheid variable star data from the SH0ES project (Riess+ 2016, J/ApJ/826/56), the SN Ia distance scale is calibrated and the Hubble constant is estimated using our optical and near-infrared sample, and these results are compared to those determined exclusively from a near-infrared subsample. The systematic effect of the supernova's host galaxy mass is investigated as a function of wavelength and is found to decrease toward redder wavelengths, suggesting this effect may be due to dust properties of the host. Using estimates of the dust extinction derived from optical and near-infrared wavelengths and applying these to the H band, we derive a Hubble constant H0=73.2+/-2.3km/s/Mpc, whereas using a simple B-V color correction applied to the B band yields H0=72.7+/-2.1km/s/Mpc. Photometry of two calibrating SNe Ia from the CSP-II sample, SN 2012ht and SN 2015F, is presented and used to improve the calibration of the SN Ia distance ladder.
- ID:
- ivo://CDS.VizieR/J/AJ/148/16
- Title:
- Updated 3CRR sample of radio sources
- Short Name:
- J/AJ/148/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the consistency of the unified scheme of Fanaroff-Riley type II radio galaxies and quasars with their observed number and size distributions in the 3CRR sample. We separate the low-excitation galaxies from the high-excitation ones, as the former might not harbor a quasar within and thus may not be partaking in the unified scheme models. In the updated 3CRR sample, at low redshifts (z<0.5), the relative number and luminosity distributions of high-excitation galaxies and quasars roughly match the expectations from the orientation-based unified scheme model. However, a foreshortening in the observed sizes of quasars, which is a must in the orientation-based model, is not seen with respect to radio galaxies even when the low-excitation galaxies are excluded. This dashes the hope that the unified scheme might still work if one includes only the high-excitation galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/126/1208
- Title:
- UVBI magnitudes and redshifts in HDF-South
- Short Name:
- J/AJ/126/1208
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 97 (*) spectroscopic redshifts of z<1 galaxies in the Hubble Deep Field South (HDF-S) and its flanking fields (FFs). In the HDF-S proper we observed approximately half the galaxies brighter than I_814_(AB)=24 and obtained redshifts for 76% of them. Targets in our HDF-S sample were preselected to be at z<1 based on photometric redshifts, while in the FFs a simple magnitude cut was used. The photometric redshift preselection in the HDF-S resulted in a spectroscopic success rate that is significantly higher than in the FFs, where no preselection was applied. The rms precision of our redshift measurements, determined from repeat observations, is {delta}z=0.0003. We present the photometry and redshifts for the 97 objects for which we secured spectroscopic redshifts and describe the basic properties of this sample. The photometry was derived from the HST observations; the spectroscopy was obtained at the VLT using the FORS2 spectrograph on the Kueyen (UT2) and Yepun (UT4) 8.2m telescopes. (*) Actually, 103 redshifts in table1.
1455. UV-bright quasars
- ID:
- ivo://CDS.VizieR/J/ApJ/690/1181
- Title:
- UV-bright quasars
- Short Name:
- J/ApJ/690/1181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Investigations of HeII Ly{alpha} (304{AA} rest-frame) absorption toward a half-dozen quasars at z~3-4 have demonstrated the great potential of helium studies of the intergalactic medium, but the current critically small sample size of clean sightlines for the HeII Gunn-Peterson test limits confidence in cosmological inferences, and a larger sample is required. Although the unobscured quasar sightlines to high redshift are extremely rare, the Sloan Digital Sky Survey (SDSS) DR6 provides thousands of z>2.8 quasars. We have cross-correlated these SDSS quasars with the Galaxy Evolution Explorer (GALEX) GR2/GR3 to establish a catalog of 200 higher-confidence (~70% secure) cases of quasars at z=2.8-5.1 potentially having surviving far-UV (rest-frame) flux. We also catalog another 112 likely far-UV-bright quasars from GALEX cross-correlation with other (non-SDSS) quasar compilations. Reconnaissance UV prism observations with the Hubble Space Telescope (HST) of 24 of our SDSS/GALEX candidates confirm 12 as detected in the far-UV, with at least nine having flux extending to very near the HeII break; with refinements our success rate is even higher. Our SDSS/GALEX selection approach is thereby confirmed to be an order of magnitude more efficient than previous HeII quasar searches, more than doubles the number of spectroscopically confirmed clean sightlines to high redshift, and provides a resource list of hundreds of high-confidence sightlines for upcoming HeII and other far-UV studies from the HST. Our reconnaissance HST prism spectra suggest some far-UV diversity, confirming the need to obtain a large sample of independent quasar sightlines across a broad redshift range to assess such issues as the epoch(s) of helium reionization, while averaging over individual-object pathology and/or cosmic variance.
1456. UV-bright quasars
- ID:
- ivo://CDS.VizieR/J/ApJS/185/20
- Title:
- UV-bright quasars
- Short Name:
- J/ApJS/185/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Absorption along quasar sightlines remains among the most sensitive direct measures of HeII reionization in much of the intergalactic medium (IGM). Until recently, fewer than a half-dozen unobscured quasar sightlines suitable for the HeII Gunn-Peterson test were known; although these handful demonstrated great promise, the small sample size limited confidence in cosmological inferences. We have recently added nine more such clean HeII quasars, exploiting Sloan Digital Sky Survey (SDSS) quasar samples, broadband ultraviolet (UV) imaging from Galaxy Evolution Explorer (GALEX), and high-yield UV spectroscopic confirmations from Hubble Space Telescope (HST). Here we markedly expand this approach by cross-correlating SDSS DR7 and GALEX GR4+5 to catalog 428 SDSS and 165 other quasars with z>2.78 having likely (~70%) GALEX detections, suggesting they are bright into the far-UV. Reconnaissance HST Cycle 16 Supplemental prism data for 29 of these new quasar-GALEX matches spectroscopically confirm 17 as indeed far-UV bright. At least 10 of these confirmations have clean sightlines all the way down to HeII Ly{alpha}, substantially expanding the number of known clean HeII quasars, and reaffirming the order of magnitude enhanced efficiency of our selection technique. Combined confirmations from this and our past programs yield more than 20 HeII quasars, quintupling the sample. These provide substantial progress toward a sample of HeII quasar sightlines large enough, and spanning a sufficient redshift range, to enable statistical IGM studies that may avoid individual object peculiarity and sightline variance. Our expanded catalog of hundreds of high-likelihood far-UV-bright QSOs additionally will be useful for understanding the extreme-UV properties of the quasars themselves.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/115
- Title:
- UV-continuum slopes beta for z~4-8 galaxies
- Short Name:
- J/ApJ/793/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the UV-continuum slope {beta} for over 4000 high-redshift galaxies over a wide range of redshifts z~4-8 and luminosities from the HST HUDF/XDF, HUDF09-1, HUDF09-2, ERS, CANDELS-N, and CANDELS-S data sets. Our new {beta} results reach very faint levels at z~4 (-15.5 mag: 0.006 L_z=3_^*^), z~5 (-16.5 mag: 0.014 L_z=3_^*^), and z~6 and z~7 (-17 mag: 0.025 L_z=3_^*^). Inconsistencies between previous studies led us to conduct a comprehensive review of systematic errors and develop a new technique for measuring {beta} that is robust against biases that arise from the impact of noise. We demonstrate, by object-by-object comparisons, that all previous studies, including our own and those done on the latest HUDF12 data set, suffered from small systematic errors in {beta}. We find that after correcting for the systematic errors (typically {Delta}{beta}~0.1-0.2) all {beta} results at z~7 from different groups are in excellent agreement. The mean {beta} we measure for faint (-18 mag: 0.1L_z=3_^*^) z~4, z~5, z~6, and z~7 galaxies is -2.03+/-0.03+/-0.06 (random and systematic errors), -2.14+/-0.06+/-0.06, -2.24+/-0.11+/-0.08, and -2.30+/-0.18+/-0.13, respectively. Our new {beta} values are redder than we have reported in the past, but bluer than other recent results. Our previously reported trend of bluer {beta}'s at lower luminosities is confirmed, as is the evolution to bluer {beta}'s at high redshifts. {beta} appears to show only a mild luminosity dependence faintward of M_UV, AB_~-19 mag, suggesting that the mean {beta} asymptotes to ~-2.2 to -2.4 for faint z>=4 galaxies. At z~7, the observed {beta}'s suggest non-zero, but low dust extinction, and they agree well with values predicted in cosmological hydrodynamical simulations.
- ID:
- ivo://CDS.VizieR/J/ApJ/824/70
- Title:
- UV-FIR SED results of SDSS QSOs and their hosts
- Short Name:
- J/ApJ/824/70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present a study of 207 quasars selected from the Sloan Digital Sky Survey quasar catalogs and the Herschel Stripe 82 survey. Quasars within this sample are high-luminosity quasars with a mean bolometric luminosity of 10^46.4^erg/s. The redshift range of this sample is within z Herschel-SPIRE bands, the quasar sample is complete yet highly biased. Based on the multi-wavelength photometric observation data, we conducted a spectral energy distribution (SED) fitting through UV to FIR. Parameters such as active galactic nucleus (AGN) luminosity, far-IR (FIR) luminosity, stellar mass, as well as many other AGN and galaxy properties are deduced from the SED fitting results. The mean star formation rate (SFR) of the sample is 419M_{sun}_/yr and the mean gas mass is ~10^11.3^M_{sun}_. All of these results point to an IR luminous quasar system. Compared with star formation main sequence (MS) galaxies, at least 80 out of 207 quasars are hosted by starburst galaxies. This supports the statement that luminous AGNs are more likely to be associated with major mergers. The SFR increases with the redshift up to z=2. It is correlated with the AGN bolometric luminosity, where L_FIR_{propto}L_Bol_^0.46+/-0.03^. The AGN bolometric luminosity is also correlated with the host galaxy mass and gas mass. Yet the correlation between L_FIR_ and L_Bol_ has higher significant level, implies that the link between AGN accretion and the SFR is more primal. The M_BH_/M_*_ ratio of our sample is 0.02, higher than the value 0.005 in the local universe. It might indicate an evolutionary trend of the M_BH_/M_*_ scaling relation.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/164
- Title:
- UV galaxies in CANDELS from z=8 to z=4
- Short Name:
- J/ApJ/756/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the evolution of galaxy rest-frame ultraviolet (UV) colors in the epoch 4<~z<~8. We use new wide-field near-infrared data in the Great Observatories Origins Deep Survey-South field from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble Ultra Deep Field (HUDF) 2009, and Early Release Science programs to select galaxies via photometric redshift measurements. Our sample consists of 2812 candidate galaxies at z>~3.5, including 113 at z=~7-8. We fit the observed spectral energy distribution to a suite of synthetic stellar population models and measure the value of the UV spectral slope ({beta}) from the best-fit model spectrum. We run simulations to show that this measurement technique results in a smaller scatter on {beta} than other methods, as well as a reduced number of galaxies with catastrophically incorrect {beta} measurements (i.e., {Delta}{beta}>1).
- ID:
- ivo://CDS.VizieR/J/AJ/162/47
- Title:
- UV luminosity in ~25000 2<z<9 galaxies
- Short Name:
- J/AJ/162/47
- Date:
- 16 Mar 2022 00:17:16
- Publisher:
- CDS
- Description:
- Here we provide the most comprehensive determinations of the rest-frame UV luminosity function (LF) available to date with the Hubble Space Telescope (HST) at z~2-9. Essentially all of the noncluster extragalactic legacy fields are utilized, including the Hubble Ultra Deep Field, the Hubble Frontier Fields parallel fields, and all five CANDELS fields, for a total survey area of 1136arcmin^2^. Our determinations include galaxies at z~2-3 leveraging the deep HDUV, UVUDF, and ERS WFC3/UVIS observations available over an ~150arcmin^2^ area in the GOODS-North and GOODS-South regions. All together, our collective samples include >24000 sources, >2.3x larger than previous selections with HST. We identify 5766, 6332, 7240, 3449, 1066, 601, 246, and 33 sources at z~2, 3, 4, 5, 6, 7, 8, and 9, respectively. Combining our results with an earlier z~10 LF determination by Oesch et al., we quantify the evolution of the UV LF. Our results indicate that there is (1) a smooth flattening of the faint-end slope {alpha} from {alpha}~-2.4 at z~10 to {alpha}~-1.5 at z~2, (2) minimal evolution in the characteristic luminosity M* at z>~2.5, and (3) a monotonic increase in the normalization log_10_\{phi}* from z~10 to 2, which can be well described by a simple second-order polynomial, consistent with an "accelerated" evolution scenario. We find that each of these trends (from z~10 to 2.5 at least) can be readily explained on the basis of the evolution of the halo mass function and a simple constant star formation efficiency model.
