- ID:
- ivo://CDS.VizieR/J/ApJ/818/L14
- Title:
- RM AGNs accretion rates and BH masses
- Short Name:
- J/ApJ/818/L14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Broad emission lines in active galactic nuclei (AGNs) mainly arise from gas photoionized by continuum radiation from an accretion disk around a central black hole. The shape of the broad-line profile, described by D_H{beta}_=FWHM/{sigma}_H{beta}_, the ratio of full width at half maximum to the dispersion of broad H{beta}, reflects the dynamics of the broad-line region (BLR) and correlates with the dimensionless accretion rate (dM/dt) or Eddington ratio (L_bot_/L_Edd_). At the same time, dM/dt and (L_bot_/L_Edd_ correlate with R_Fe_, the ratio of optical Fe ii to H{beta} line flux emission. Assembling all AGNs with reverberation mapping measurements of broad H{beta}, both from the literature and from new observations reported here, we find a strong bivariate correlation of the form log((dM/dt.L_bot_/L_Edd_)={alpha}+{beta}D_H{beta}_+{gamma}R_Fe_ where {alpha}=(2.47,0.31), {beta}=-(1.59,0.82), and {gamma}=(1.34,0.80). We refer to this as the fundamental plane of the BLR. We apply the plane to a sample of z<0.8 quasars to demonstrate the prevalence of super-Eddington accreting AGNs are quite common at low redshifts.
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- 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/782/45
- Title:
- SEAMBHs. I. Mrk 142, Mrk 335, and IRAS F12397+3333
- Short Name:
- J/ApJ/782/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs in being powered by slim accretion disks and showing saturated accretion luminosities, but both are not yet fully understood. The results are part of a large reverberation mapping (RM) campaign using the 2.4m Shangri-La telescope at the Yunnan Observatory in China. The goals are to investigate the gas distribution near the BH and the properties of the central accretion disks, to measure BH mass and Eddington ratios, and to test the feasibility of using such objects as a new type of cosmological candles. The paper presents results for three objects, Mrk 335, Mrk 142, and IRAS F12397+3333, with H{beta} time lags relative to the 5100{AA} continuum of 10.6_-2.9_^+1.7^, 6.4_-2.2_^+0.8^ and 11.4_-1.9_^+2.9^ days, respectively. The corresponding BH masses are (8.3_-3.2_^+2.6^)x10^6^M_{sun}_, (3.4_-1.2_^+0.5^)x10^6^M_{sun}_, and (7.5_-4.1_^+4.3^x10^6^M_{sun}_, and the lower limits on the Eddington ratios are 0.6, 2.3, and 4.6 for the minimal radiative efficiency of 0.038. Mrk 142 and IRAS F12397+333 (extinction corrected) clearly deviate from the currently known relation between H{beta} lag and continuum luminosity. The three Eddington ratios are beyond the values expected in thin accretion disks and two of them are the largest measured so far among objects with RM-based BH masses. We briefly discuss implications for slim disks, BH growth, and cosmology.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/22
- Title:
- SEAMBHs IV. H{beta} time lags
- Short Name:
- J/ApJ/806/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have completed two years of photometric and spectroscopic monitoring of a large number of active galactic nuclei (AGNs) with very high accretion rates. In this paper, we report on the result of the second phase of the campaign, during 2013-2014, and the measurements of five new H{beta} time lags out of eight monitored AGNs. All five objects were identified as super-Eddington accreting massive black holes (SEAMBHs). The highest measured accretion rates for the objects in this campaign are dM/dt>~200, where dM/dt=dM/dt_{dot}_/L_Edd_C^-2^, dM/dt_{dot}_ is the mass accretion rates, L_Edd_ is the Eddington luminosity and c is the speed of light.
- ID:
- ivo://CDS.VizieR/J/ApJ/856/6
- Title:
- SEAMBHs IX. 10 new H{beta} light curves
- Short Name:
- J/ApJ/856/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As one paper in a series reporting on a large reverberation mapping campaign of super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs), we present the results of 10 SEAMBHs monitored spectroscopically during 2015-2017. Six of them are observed for the first time, and have generally higher 5100{AA} luminosities than the SEAMBHs monitored in our campaign from 2012 to 2015; the remaining four are repeat observations to check if their previous lags change. Similar to the previous SEAMBHs, the H{beta} time lags of the newly observed objects are shorter than the values predicted by the canonical RH{beta}-L5100 relation of sub-Eddington AGNs, by factors of ~2-6, depending on the accretion rate. The four previously observed objects have lags consistent with previous measurements. We provide linear regressions for the RH{beta}-L5100 relation, solely for the SEAMBH sample and for low-accretion AGNs. We find that the relative strength of Fe ii and the profile of the H{beta} emission line can be used as proxies of accretion rate, showing that the shortening of H{beta} lags depends on accretion rates. The recent SDSS-RM discovery of shortened H{beta} lags in AGNs with low accretion rates provides compelling evidence for retrograde accretion onto the black hole. These evidences show that the canonical RH{beta}-L5100 relation holds only in AGNs with moderate accretion rates. At low accretion rates, it should be revised to include the effects of black hole spin, whereas the accretion rate itself becomes a key factor in the regime of high accretion rates.
- 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/A+A/658/A160
- Title:
- SEDIGISM survey, search for molecular outflows
- Short Name:
- J/A+A/658/A160
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The formation processes of massive stars are still unclear but a picture is emerging involving accretion disks and molecular outflows in what appears to be a scaled-up version of lower-mass star formation. A census of outflow activity towards high-mass star-forming clumps in various evolutionary stages has the potential to shed light on high-mass star formation. We conduct an outflow survey toward ATLASGAL (APEX Telescope Large Area Survey of the Galaxy) clumps, using SEDIGISM (structure, Excitation, and Dynamics of the Inner Galactic InterStellar Medium) data and aim to obtain a large sample of clumps exhibiting outflow activity in different evolutionary stages. We identify the high-velocity wings of the ^13^CO lines, indicating outflow activity, toward ATLASGAL clumps by (1) extracting the simultaneously observed ^13^CO(2-1) and C^18^O(2-1) spectra from SEDIGISM, and (2) subtracting the scaled C^18^O (cores emission) from the ^13^CO, after considering opacity broadening. We have detected high-velocity gas towards 1192 clumps out of a total sample of 2052 corresponding to an overall detection rate of 58%. Outflow activity has been detected from the earliest (apparently) quiescent clumps (i.e., 70 microns weak), to the most evolved HII region stages (i.e., 8 micron bright with tracers of massive star formation). The detection rate increases as a function of evolution (quiescent = 51%, protostellar = 47%, YSO = 57%, UCHII regions = 76%). Our sample is the largest outflow sample identified so far. The high detection rate from this large sample is consistent with the results of similar studies reported in the literature and supports the scenario that outflows are a ubiquitous feature of high-mass star formation. The lower detection rate in early evolutionary stages could be due to the fact that outflows in the early stages are weak and difficult to detect. We obtain a statistically significant number of outflow clumps for every evolutionary stage, especially for outflow clumps in the earliest stages (i.e., 70 microns dark cloud or massive starless core).
- ID:
- ivo://CDS.VizieR/J/A+A/621/A119
- Title:
- SgrA* and NRAS530 86GHz images
- Short Name:
- J/A+A/621/A119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The compact radio source Sagittarius A* (Sgr A*) in the Galactic centre is the primary supermassive black hole candidate. General relativistic magnetohydrodynamical (GRMHD) simulations of the accretion flow around Sgr A* predict the presence of sub-structure at observing wavelengths of ~3mm and below (frequencies of 86GHz and above). For very long baseline interferometry (VLBI) observations of Sgr A* at this frequency the blurring effect of interstellar scattering becomes sub-dominant, and arrays such as the high sensitivity array (HSA) and the global mm-VLBI array (GMVA) are now capable of resolving potential sub-structure in the source. Such investigations help to improve our understanding of the emission geometry of the mm-wave emission of Sgr A*, which is crucial for constraining theoretical models and for providing a background to interpret 1mm VLBI data from the Event Horizon Telescope (EHT). Following the closure phase analysis in our first paper, which indicates asymmetry in the 3 mm emission of Sgr A*, here we have used the full visibility information to check for possible sub-structure. We extracted source size information from closure amplitude analysis, and investigate how this constrains a combined fit of the size-frequency relation and the scattering law for Sgr A*. We performed high-sensitivity VLBI observations of Sgr A* at 3mm using the Very Long Baseline Array (VLBA) and the Large Millimeter Telescope (LMT) in Mexico on two consecutive days in May 2015, with the second epoch including the Greenbank Telescope (GBT). We confirm the asymmetry for the experiment including GBT. Modelling the emission with an elliptical Gaussian results in significant residual flux of ~10mJy in south-eastern direction. The analysis of closure amplitudes allows us to precisely constrain the major and minor axis size of the main emission component. We discuss systematic effects which need to be taken into account. We consider our results in the context of the existing body of size measurements over a range of observing frequencies and investigate how well-constrained the size-frequency relation is by performing a simultaneous fit to the scattering law and the size-frequency relation. We find an overall source geometry that matches previous findings very closely, showing a deviation in fitted model parameters less than 3% over a time scale of weeks and suggesting a highly stable global source geometry over time. The reported sub-structure in the 3mm emission of Sgr A* is consistent with theoretical expectations of refractive noise on long baselines. However, comparing our findings with recent results from 1mm and 7mm VLBI observations, which also show evidence for east-west asymmetry, we cannot exclude an intrinsic origin. Confirmation of persistent intrinsic substructure will require further VLBI observations spread out over multiple epochs.
- ID:
- ivo://CDS.VizieR/J/AJ/129/363
- Title:
- Spectroscopy in Orion Nebula Cluster
- Short Name:
- J/AJ/129/363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from high-resolution spectra of 237 stars in the Orion Nebula cluster (ONC) obtained during two engineering runs with the Hectochelle multifiber echelle spectrograph on the 6.5m MMT. The ONC is the nearest populous young (age ~1Myr) cluster and is therefore an important object for studies of the evolution of protoplanetary disks. Using the high spectral resolution of Hectochelle, we are able to distinguish stellar accretion and wind emission-line profiles from nebular emission lines and identify accreting members of the cluster from H{alpha} profiles with greater accuracy than previously possible. We find 15 new members on the basis of Li {lambda}6707 absorption and H{alpha} emission. Line profiles of H{alpha} of some objects that are not too contaminated by nebular emission show features characteristic of mass inflow and ejection. We also present rotational velocities as part of an initial investigation into angular momentum evolution of very young stars, confirming a difference between classical T Tauri stars and weak-line T Tauri stars that had been found from period analysis. Finally, we present an initial study of the radial velocity dispersion of the brighter stars in the central cluster. The very small dispersion derived, 1.8km/s, is in good agreement with estimates from proper motions.
- ID:
- ivo://CDS.VizieR/J/AJ/153/188
- Title:
- Spectroscopy of the foreground population in Orion A
- Short Name:
- J/AJ/153/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a spectroscopic survey of the foreground population in Orion A with MMT/Hectospec. We use these data, along with archival spectroscopic data and photometric data, to derive spectral types, extinction values, and masses for 691 stars. Using the Spitzer Space Telescope data, we characterize the disk properties of these sources. We identify 37 new transition disk (TD) objects, 1 globally depleted disk candidate, and 7 probable young debris disks. We discover an object with a mass of less than 0.018-0.030 M_{sun}_, which harbors a flaring disk. Using the H{alpha} emission line, we characterize the accretion activity of the sources with disks, and confirm that the fraction of accreting TDs is lower than that of optically thick disks (46%+/-7% versus 73%+/-9%, respectively). Using kinematic data from the Sloan Digital Sky Survey and APOGEE INfrared Spectroscopy of the Young Nebulous Clusters program (IN-SYNC), we confirm that the foreground population shows similar kinematics to their local molecular clouds and other young stars in the same regions. Using the isochronal ages, we find that the foreground population has a median age of around 1-2 Myr, which is similar to that of other young stars in Orion A. Therefore, our results argue against the presence of a large and old foreground cluster in front of Orion A.
