Jenny E. Greene

Bio: Jenny E. Greene is an academic researcher from Princeton University. The author has contributed to research in topics: Galaxy & Active galactic nucleus. The author has an hindex of 54, co-authored 237 publications receiving 10133 citations. Previous affiliations of Jenny E. Greene include Sloan Fellows & University of Texas at Austin.

The Low-luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei

Abstract: We present an updated and revised analysis of the relationship between the H{beta} broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H{beta} time lag, which is assumed to yield the average H{beta} BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R{sub BLR}-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of {alpha}= 0.533{sup +0.035}{sub -0.033}, consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19more » {+-} 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R{sub BLR}-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.« less

Biases in Virial Black Hole Masses: An SDSS Perspective

Abstract: We compile black hole (BH) masses for ~60,000 quasars in the redshift range 0.1 z 4.5 included in the Fifth Data Release of the Sloan Digital Sky Survey, using virial BH mass estimators based on the Hβ, Mg II, and C IV emission lines. Within our sample, the widths of the three lines follow lognormal distributions, with means and dispersions that do not depend strongly on luminosity or redshift. The Mg II- and Hβ-estimated BH masses are consistent with one another, but there is a positive bias between the C IV- and Mg II-estimated BH masses correlated with the C IV-Mg II blueshift, suggesting that the C IV estimator is more severely affected by a disk wind. If the underlying BH mass distribution decreases with mass and the Eddington ratio distribution at fixed true BH mass has nonzero width, we show that the measured virial BH mass and Eddington ratio distributions within finite luminosity bins are subject to Malmquist bias. We present a model that reproduces the observed virial mass distribution, quasar luminosity function, and line width distribution of our sample; it has an underlying BH mass distribution dN/dlog M ∝ M−2.6 and a lognormal true Eddington ratio distribution at fixed true mass with dispersion 0.4 dex and mean dependent on BH mass. In this model, the observed virial mass (Eddington ratio) distribution for the SDSS sample is biased high (low) by ~0.6 dex within finite luminosity bins. Finally, we compare virial BH masses of radio and broad absorption line quasars with ordinary quasars matched in redshift and luminosity.

Dwarf galaxies with optical signatures of active massive black holes

Abstract: We present a sample of 151 dwarf galaxies (10{sup 8.5} ∼< M{sub *} ∼< 10{sup 9.5} M{sub ☉}) that exhibit optical spectroscopic signatures of accreting massive black holes (BHs), increasing the number of known active galaxies in this stellar-mass range by more than an order of magnitude. Utilizing data from the Sloan Digital Sky Survey Data Release 8 and stellar masses from the NASA-Sloan Atlas, we have systematically searched for active BHs in ∼25,000 emission-line galaxies with stellar masses comparable to the Magellanic Clouds and redshifts z < 0.055. Using the narrow-line [O III]/Hβ versus [N II]/Hα diagnostic diagram, we find photoionization signatures of BH accretion in 136 galaxies, a small fraction of which also exhibit broad Hα emission. For these broad-line active galactic nucleus (AGN) candidates, we estimate BH masses using standard virial techniques and find a range of 10{sup 5} ∼< M{sub BH} ∼< 10{sup 6} M{sub ☉} and a median of M{sub BH} ∼ 2 × 10{sup 5} M{sub ☉}. We also detect broad Hα in 15 galaxies that have narrow-line ratios consistent with star-forming galaxies. Follow-up observations are required to determine if these are true type 1 AGN or if the broad Hα is from stellarmore » processes. The median absolute magnitude of the host galaxies in our active sample is M{sub g} = –18.1 mag, which is ∼1-2 mag fainter than previous samples of AGN hosts with low-mass BHs. This work constrains the smallest galaxies that can form a massive BH, with implications for BH feedback in low-mass galaxies and the origin of the first supermassive BH seeds.« less

A New Sample of Low-Mass Black Holes in Active Galaxies

Abstract: We present an expanded sample of low-mass black holes (BHs) found in galactic nuclei. Using standard virial mass techniques to estimate BH masses, we select from the Fourth Data Release of the Sloan Digital Sky Survey all broad-line active galaxies with masses <2 × 106 M☉. BHs in this mass regime provide unique tests of the relationship between BHs and galaxies, since their late-type galaxy hosts do not necessarily contain classical bulges. Furthermore, they provide observational analogs of primordial seed BHs and are expected, when merging, to provide strong gravitational signals for future detectors such as LISA. From our preliminary sample of 19, we have increased the total sample by an order of magnitude to 174, as well as an additional 55 (less secure) candidates. The sample has a median BH mass of MBH = 1.3 × 106 M☉, and in general the objects are radiating at high fractions of their Eddington limits. We investigate the broad spectral properties of the sample; 55 are detected by ROSAT, with soft X-ray luminosities in the range 1040 to 7 × 1043 ergs s-1. Much like the preliminary sample, these objects are predominantly radio-quiet (R ≡ f6cm/f4400A < 10), but 11 objects are detected at 20 cm, with radio powers (1021-1023 W Hz-1) that may arise from either star formation or nuclear activity; only 1% of the sample is radio-loud. We further confirm that, with Mg = -19.3 and g - r = 0.7 mag, the host galaxies are low-mass, late-type systems. At least 40% show disklike morphologies, and the combination of host galaxy colors and higher order Balmer absorption lines indicate intermediate-age stellar populations in a subset of the sample.

The Mass Function of Active Black Holes in the Local Universe

Abstract: We present the first measurement of the BH mass function for broad-line active galaxies in the local universe. Using the ~8500 broad-line active galaxies from SDSS DR4, we construct a broad-line luminosity function that agrees very well with the local soft X-ray luminosity function. Using standard virial relations, we then convert observed broad-line luminosities and widths into BH masses. A mass function constructed in this way has the unique capability to probe the mass region <106 M☉, which, while insignificant in terms of total BH mass density, nevertheless may place important constraints on the mass distribution of seed BHs in the early universe. The characteristic local active BH has a mass of ~107 M☉ radiating at 10% of the Eddington rate. The active fraction is a strong function of BH mass; at both higher and lower masses the active mass function falls more steeply than one would infer from the distribution of bulge luminosity. The deficit of local massive radiating BHs is a well-known phenomenon, while we present the first robust measurement of a decline in the space density of active BHs at low mass.

Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies

Abstract: Supermassive black holes (BHs) have been found in 85 galaxies by dynamical modeling of spatially resolved kinematics. The Hubble Space Telescope revolutionized BH research by advancing the subject from its proof-of-concept phase into quantitative studies of BH demographics. Most influential was the discovery of a tight correlation between BH mass and the velocity dispersion σ of the bulge component of the host galaxy. Together with similar correlations with bulge luminosity and mass, this led to the widespread belief that BHs and bulges coevolve by regulating each other's growth. Conclusions based on one set of correlations from in brightest cluster ellipticals to in the smallest galaxies dominated BH work for more than a decade. New results are now replacing this simple story with a richer and more plausible picture in which BHs correlate differently with different galaxy components. A reasonable aim is to use this progress to refine our understanding of BH-galaxy coevolution. BHs with masses of 105−106M...

LSST: from Science Drivers to Reference Design and Anticipated Data Products

Abstract: (Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pachon in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.

The eleventh and twelfth data releases of the Sloan Digital Sky Survey: final data from SDSS-III

Abstract: The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 sq. deg of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-Object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include measured abundances of 15 different elements for each star. In total, SDSS-III added 2350 sq. deg of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 sq. deg; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5,513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.

Observational Evidence of Active Galactic Nuclei Feedback

Abstract: Radiation, winds, and jets from the active nucleus of a massive galaxy can interact with its interstellar medium, and this can lead to ejection or heating of the gas. This terminates star formation in the galaxy and stifles accretion onto the black hole. Such active galactic nuclei (AGN) feedback can account for the observed proportionality between the central black hole and the host galaxy mass. Direct observational evidence for the radiative or quasar mode of feedback, which occurs when AGN are very luminous, has been difficult to obtain but is accumulating from a few exceptional objects. Feedback from the kinetic or radio mode, which uses the mechanical energy of radio-emitting jets often seen when AGN are operating at a lower level, is common in massive elliptical galaxies. This mode is well observed directly through X-ray observations of the central galaxies of cool core clusters in the form of bubbles in the hot surrounding medium. The energy flow, which is roughly continuous, heats the hot intraclu...

Observational Evidence of AGN Feedback

Abstract: Radiation, winds and jets from the active nucleus of a massive galaxy can interact with its interstellar medium leading to ejection or heating of the gas. This can terminate star formation in the galaxy and stifle accretion onto the black hole. Such Active Galactic Nucleus (AGN) feedback can account for the observed proportionality between central black hole and host galaxy mass. Direct observational evidence for the radiative or quasar mode of feedback, which occurs when the AGN is very luminous, has been difficult to obtain but is accumulating from a few exceptional objects. Feedback from the kinetic or radio mode, which uses the mechanical energy of radio-emitting jets often seen when the AGN is operating at a lower level, is common in massive elliptical galaxies. This mode is well observed directly through X-ray observations of the central galaxies of cool core clusters in the form of bubbles in the hot surrounding medium. The energy flow, which is roughly continuous, heats the hot intracluster gas and reduces radiative cooling and subsequent star formation by an order of magnitude. Feedback appears to maintain a long-lived heating/cooling balance. Powerful, jetted radio outbursts may represent a further mode of energy feedback which affect the cores of groups and subclusters. New telescopes and instruments from the radio to X-ray bands will come into operation over the next few years and lead to a rapid expansion in observational data on all modes of AGN feedback.