arXiv subjects

Matthew A. Malkan

Publications and source records attributed to Matthew A. Malkan.

At least 145 records · Page 8Linked to original sources

arXiv2013

Fueling AGN-I: How the Global Characteristics of the Central Kiloparsec of Seyferts differ from Quiescent Galaxies

In a matched sample of Seyfert and quiescent galaxies we simultaneously probe the stellar and molecular gas kinematics from 1 kpc down to 50 pc with the aim of identifying the dynamical processes dictating black hole accretion rates. This first paper compares the global characteristics of a sample of ten galaxies. We find several differences within a radius of 500 pc that are correlated with Active Galactic Nucleus (AGN) activity. The Seyferts have: (1) a more centrally concentrated nuclear stellar surface brightness with lower stellar luminosities beyond a radius of 100 pc, (2) a lower stellar velocity dispersion within a radius of 200 pc, (3) elevated H2 luminosity out to a radius of at least 250 pc, and (4) more centrally concentrated H2 surface brightness profiles. These observed differences can be interpreted as evidence for Seyfert galaxies having a dynamically cold (in comparison to the bulge) nuclear structure composed of a significant gas reservoir and a relatively young stellar population. This structure is undetected (and possibly does not exist) in quiescent galaxies. The presence of such a nuclear structure in Seyfert galaxies provides evidence for inflow of the surrounding interstellar medium since the nuclear stellar population requires a supply of gas from which to form. The fueling of a Seyfert AGN is thus associated with the formation of a dynamically cold component of gas and stars on scales of hundreds of parsecs.

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arXiv2013

The Lick AGN Monitoring Project 2011: Fe II Reverberation from the Outer Broad-Line Region

The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with only limited success. Here we report the detection of Fe II reverberation in two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory in Spring 2011. Light curves for emission lines including H-beta and Fe II were measured by applying a fitting routine to decompose the spectra into several continuum and emission-line components, and we use cross-correlation techniques to determine the reverberation lags of the emission lines relative to V-band light curves. In both cases the measured lag (t_cen) of Fe II is longer than that of H-beta, although the inferred lags are somewhat sensitive to the choice of Fe II template used in the fit. For spectral decompositions done using the Fe II template of Veron-Cetty et al. (2004), we find t_cen(Fe II)/t_cen(H-beta) = 1.9+-0.6 in NGC 4593 and 1.5+-0.3 in Mrk 1511. The detection of highly correlated variations between Fe II and continuum emission demonstrates that the Fe II emission in these galaxies originates in photoionized gas, located predominantly in the outer portion of the broad-line region.

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arXiv2013

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

We present an updated and revised analysis of the relationship between the Hbeta 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 9 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 Hbeta time lag, which is assumed to yield the average Hbeta 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-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of alpha = 0.533 (+0.035/-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 0.19(+/-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-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.

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arXiv2012

A Determination of the Intergalactic Redshift Dependent UV-Optical-NIR Photon Density Using Deep Galaxy Survey Data and the Gamma-ray Opacity of the Universe

We calculate the intensity and photon spectrum of the intergalactic background light (IBL) as a function of redshift using an approach based on observational data obtained in many different wavelength bands from local to deep galaxy surveys. This allows us to obtain an empirical determination of the IBL and to quantify its observationally based uncertainties. Using our results on the IBL, we then place 68% confidence upper and lower limits on the opacity of the universe to gamma-rays, free of the theoretical assumptions that were needed for past calculations. We compare our results with measurements of the extragalactic background light and upper limits obtained from observations made by the Fermi Gamma-ray Space Telescope.

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arXiv2012

Unusual Long and Luminous Optical Transient in the Subaru Deep Field

We present observations of SDF-05M05, an unusual optical transient discovered in the Subaru Deep Field (SDF). The duration of the transient is > ~800 d in the observer frame, and the maximum brightness during observation reached approximately 23 mag in the i' and z' bands. The faint host galaxy is clearly identified in all 5 optical bands of the deep SDF images. The photometric redshift of the host yields z~0.6 and the corresponding absolute magnitude at maximum is ~-20. This implies that this event shone with an absolute magnitude brighter than -19 mag for approximately 300 d in the rest frame, which is significantly longer than a typical supernova and ultra-luminous supernova. The total radiated energy during our observation was 1x10^51 erg. The light curves and color evolution are marginally consistent with some of luminous IIn supernova. We suggest that the transient may be a unique and peculiar supernova at intermediate redshift.

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arXiv2012

A Ly-alpha Emitter with an Extremely Large Rest-frame Equivalent Width of ~900A at z=6.5: A Candidate of Population III-dominated Galaxy?

We have identified a very interesting Ly-alpha emitter, whose Ly-alpha emission line has an extremely large observed equivalent width of EW_0=436^{+422}_{-149}A, which corresponds to an extraordinarily large intrinsic rest-frame equivalent width of EW_0^{int}=872^{+844}_{-298}A after the average intergalactic absorption correction. The object was spectroscopically confirmed to be a real Ly-alpha emitter by its apparent asymmetric Ly-alpha line profile detected at z=6.538. The continuum emission of the object was definitely detected in our deep z'-band image; thus, its EW_0 was reliably determined. Follow-up deep near-infrared spectroscopy revealed emission lines of neither He II lambda1640 as an apparent signature of Population III, nor C IV lambda1549 as a proof of active nucleus. No detection of short-lived He II lambda1640 line is not necessarily inconsistent with the interpretation that the underlying stellar population of the object is dominated by Population III. We found that the observed extremely large EW_0 of the Ly-alpha emission and the upper limit on the EW_0 of the He II lambda1640 emission can be explained by population synthesis models favoring a very young age less than 2-4Myr and massive metal-poor (Z<10^{-5}) or even metal-free stars. The observed large EW_0 of Ly-alpha is hardly explained by Population I/II synthesis models with Z>10^{-3}. However, we cannot conclusively rule out the possibility that this object is composed of a normal stellar population with a clumpy dust distribution, which could enhance the Ly-alpha EW_0, though its significance is still unclear.

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arXiv2012

The Stellar Population and Star Formation Rates of z~1.5-1.6 [O II] Emitting Galaxies Selected from Narrow-Band Emission-Line Surveys

We present the first detailed study of the stellar populations of star-forming galaxies at z~1.5, which are selected by their [O II] emission line, detected in narrow-band surveys. We identified ~1,300 [O II] emitters at z=1.47 and z=1.62 in the Subaru Deep Field with rest-frame EWs above 13Å. Optical and near-infrared spectroscopic observations for ~10% of our samples show that our separation of [O II] from [O III] emission-line galaxies in two-color space is 99% successful. We analyze the multi-wavelength properties of a subset of ~1,200 galaxies with the best photometry. They have average rest-frame EW of 45Å, stellar mass of 3 x 10^9 M_sun, and stellar age of 100 Myr. In addition, our SED fitting and broad-band colors indicate that [O II] emitters span the full range of galaxy populations at z~1.5. We also find that 80% of [O II] emitters are also photometrically classified as "BX/BM" (UV) galaxies and/or the star-forming "BzK" (near-IR) galaxies. Our [O II] emission line survey produces a far more complete, and somewhat deeper sample of z~1.5 galaxies than either the BX/BM or sBzK selection alone. We constructed average SEDs and find that higher [O II] EW galaxies have somewhat bluer continua. SED model-fitting shows that they have on average half the stellar mass of galaxies with lower [O II] EW. The observed [O II] luminosity is well-correlated with the far-UV continuum with a logarithmic slope slightly 0f 0.89\pm0.22. The scatter of the [O II] luminosity against the far-UV continuum suggests that [O II] can be used as a SFR indicator with a reliability of 0.23 dex.

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arXiv2012

The Lick AGN Monitoring Project 2011: Dynamical Modeling of the Broad Line Region in Mrk 50

We present dynamical modeling of the broad line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6(+1.2,-0.9) light days, a width of the BLR of 6.9(+1.2,-1.1) light days, and a disk opening angle of 25\pm10 degrees above the plane. We also constrain the inclination angle to be 9(+7,-5) degrees, close to face-on. Finally, the black hole mass of Mrk 50 is inferred to be log10(M(BH)/Msun) = 7.57(+0.44,-0.27). By comparison to the virial black hole mass estimate from traditional reverberation mapping analysis, we find the normalizing constant (virial coefficient) to be log10(f) = 0.78(+0.44,-0.27), consistent with the commonly adopted mean value of 0.74 based on aligning the M(BH)-σ* relation for AGN and quiescent galaxies. While our dynamical model includes the possibility of a net inflow or outflow in the BLR, we cannot distinguish between these two scenarios.

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arXiv2012

Reliable Identifications of AGN from the WISE, 2MASS and Rosat all-sky surveys

We have developed the "S_IX" statistic to identify bright, highly-likely Active Galactic Nucleus (AGN) candidates solely on the basis of WISE, 2MASS and Rosat all-sky survey data. This statistic was optimized with data from the preliminary WISE survey and the SDSS, and tested with Lick 3-m Kast spectroscopy. We find that sources with S_IX < 0 have a <~95% likelihood of being an AGN (defined in this paper as a Seyfert 1, quasar or blazar). This statistic was then applied to the full WISE/2MASS/RASS dataset, including the final WISE data release, to yield the "W2R" sample of 4,316 sources with S_IX < 0. Only 2,209 of these sources are currently in the Veron-Cetty and Veron (VCV) catalog of spectroscopically confirmed AGN, indicating that the W2R sample contains nearly 2,000 new, relatively bright (J <~ 16) AGN. We utilize the W2R sample to quantify biases and incompleteness in the VCV catalog. We find it is highly complete for bright (J < 14), northern AGN, but the completeness drops below 50% for fainter, southern samples and for sources near the Galactic plane. This approach also led to the spectroscopic identification of 10 new AGN in the Kepler field, more than doubling the number of AGN being monitored by Kepler. This has identified ~1 bright AGN every 10 square degrees, permitting construction of AGN samples in any sufficiently large region of sky.

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arXiv2012

Discovery of a protocluster at z~6

We report the discovery of a protocluster at z~6 containing at least eight cluster member galaxies with spectroscopic confirmations in the wide-field image of the Subaru Deep Field (SDF). The overdensity of the protocluster is significant at the 6 sigma level, based on the surface number density of i'-dropout galaxies. The overdense region covers ~36 sq. arcmin, and includes 30 i'-dropout galaxies. Follow-up spectroscopy revealed that 15 of these are real z~6 galaxies (5.7 < z < 6.3). Eight of the 15 are clustering in a narrow redshift range centered at z=6.01, corresponding to a seven-fold increase in number density over the average in redshift space. We found no significant difference in the observed properties, such as Ly-alpha luminosities and UV continuum magnitudes, between the eight protocluster members and the seven non-members. The velocity dispersion of the eight protocluster members is 647 km/s, which is about three times higher than that predicted by the standard cold dark matter model. This discrepancy could be attributed to the distinguishing three-dimensional distribution of the eight protocluster members. We discuss two possible explanations for this discrepancy: either the protocluster is already mature, with old galaxies at the center, or it is still immature and composed of three subgroups merging to become a larger cluster. In either case, this concentration of z=6.01 galaxies in the SDF may be one of the first sites of formation of a galaxy cluster in the universe.

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arXiv2012

Dust Attenuation and H-alpha Star Formation Rates of z~0.5 Galaxies

Using deep narrow-band and broad-band imaging, we identify 401 z~0.40 and 249 z~0.49 H-alpha line-emitting galaxies in the Subaru Deep Field. Compared to other H-alpha surveys at similar redshifts, our samples are unique since they probe lower H-alpha luminosities, are augmented with multi-wavelength (rest-frame 1000AA--1.5 microns) coverage, and a large fraction (20%) of our samples has already been spectroscopically confirmed. Our spectra allow us to measure the Balmer decrement for nearly 60 galaxies with H-beta detected above 5-sigma. The Balmer decrements indicate an average extinction of A(H-alpha)=0.7^{+1.4}_{-0.7} mag. We find that the Balmer decrement systematically increases with higher H-alpha luminosities and with larger stellar masses, in agreement with previous studies with sparser samples. We find that the SFRs estimated from modeling the spectral energy distribution (SED) is reliable---we derived an "intrinsic" H-alpha luminosity which is then reddened assuming the color excess from SED modeling. The SED-predicted H-alpha luminosity agrees with H-alpha narrow-band measurements over 3 dex (rms of 0.25 dex). We then use the SED SFRs to test different statistically-based dust corrections for H-alpha and find that adopting one magnitude of extinction is inappropriate: galaxies with lower luminosities are less reddened. We find that the luminosity-dependent dust correction of Hopkins et al. yields consistent results over 3 dex (rms of 0.3 dex). Our comparisons are only possible by assuming that stellar reddening is roughly half of nebular reddening. The strong correspondence argue that with SED modeling, we can derive reliable intrinsic SFRs even in the absence of H-alpha measurements at z~0.5.

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arXiv2011

AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies

We present the mid-infrared (MIR) properties of galaxies within a supercluster in the North Ecliptic Pole region at z?0.087 observed with the AKARI satellite. We use data from the AKARI NEP-Wide (5.4 deg2) IR survey and the CLusters of galaxies EVoLution studies (CLEVL) mission program. We show that near-IR (3 μm)-mid- IR (11 μm) color can be used as an indicator of the specific star formation rate and the presence of intermediate age stellar populations. From the MIR observations, we find that red-sequence galaxies consist not only of passively evolving red early-type galaxies, but also of 1) "weak-SFG" (disk-dominated star-forming galaxies which have star formation rates lower by \sim 4 \times than blue-cloud galaxies), and 2) "intermediate- MXG" (bulge-dominated galaxies showing stronger MIR dust emission than normal red early-type galaxies). Those two populations can be a set of transition galaxies from blue, star-forming, late-type galaxies evolving into red, quiescent, early-type ones. We find that the weak-SFG are predominant at intermediate masses (1010M\odot < M\star < 1010.5M\odot) and are typically found in local densities similar to the outskirts of galaxy clusters. As much as 40% of the supercluster member galaxies in this mass range can be classified as weak-SFGs, but their proportion decreases to < 10% at larger masses (M\star > 1010.5 M\odot) at any galaxy density. The fraction of the intermediate-MXG among red- sequence galaxies at 1010M\odot < M\star < 1011M\odot also decreases as the density and mass increase. In particular, \sim42% of the red-sequence galaxies with early-type morphologies are classified as intermediate-MXG at intermediate densities. These results suggest that the star formation activity is strongly dependent on the stellar mass, but that the morphological transformation is mainly controlled by the environment.

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arXiv2011

The Lick AGN Monitoring Project: Recalibrating Single-Epoch Virial Black Hole Mass Estimates

We investigate the calibration and uncertainties of black hole mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for 9 local Seyfert 1 galaxies with black hole masses < 10^8 M_sun. By decomposing the spectra into their AGN and stellar components, we study the variability of the single-epoch Hbeta line width (full width at half-maximum intensity, FWHM_Hbeta; or dispersion, sigma_Hbeta) and of the AGN continuum luminosity at 5100A (L_5100). From the distribution of the "virial products" (~ FWHM_Hbeta^2 L_5100^0.5 or sigma_Hbeta^2 L_5100^0.5) measured from SE spectra, we estimate the uncertainty due to the combined variability as ~ 0.05 dex (12%). This is subdominant with respect to the total uncertainty in SE mass estimates, which is dominated by uncertainties in the size-luminosity relation and virial coefficient, and is estimated to be ~ 0.46 dex (factor of ~ 3). By comparing the Hbeta line profile of the SE, mean, and root-mean-square (rms) spectra, we find that the Hbeta line is broader in the mean (and SE) spectra than in the rms spectra by ~ 0.1 dex (25%) for our sample with FWHM_Hbeta < 3000 km/s. This result is at variance with larger mass black holes where the difference is typically found to be much less than 0.1 dex. To correct for this systematic difference of the Hbeta line profile, we introduce a line-width dependent virial factor, resulting in a recalibration of SE black hole mass estimators for low-mass AGNs.

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arXiv2011

The Relation between Black Hole Mass and Host Spheroid Stellar Mass out to z~2

We combine Hubble Space Telescope images from the Great Observatories Origins Deep Survey with archival Very Large Telescope and Keck spectra of a sample of 11 X-ray selected broad-line active galactic nuclei in the redshift range 1<z<2 to study the black hole mass - stellar mass relation out to a lookback time of 10 Gyrs. Stellar masses of the spheroidal component are derived from multi-filter surface photometry. Black hole masses are estimated from the width of the broad MgII emission line and the 3000A nuclear luminosity. Comparing with a uniformly measured local sample and taking into account selection effects, we find evolution in the form M_BH/M_spheroid ~ (1+z)^(1.96+/-0.55), in agreement with our earlier studies based on spheroid luminosity. However, this result is more accurate because it does not require a correction for luminosity evolution and therefore avoids the related and dominant systematic uncertainty. We also measure total stellar masses. Combining our sample with data from the literature, we find M_BH/M_host ~ (1+z)^(1.15+/-0.15), consistent with the hypothesis that black holes (in the range M_BH ~ 10^8-9 M_sun) predate the formation of their host galaxies. Roughly one third of our objects reside in spiral galaxies; none of the host galaxies reveal signs of interaction or major merger activity. Combined with the slower evolution in host stellar masses compared to spheroid stellar masses, our results indicate that secular evolution or minor mergers play a non-negligible role in growing both BHs and spheroids.

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arXiv2011

A Census of Star-Forming Galaxies at z = 1-3 in the Subaru Deep Field

Several UV and near-infrared color selection methods have identified galaxies at z = 1-3. Since each method suffers from selection biases, we have applied three leading techniques (Lyman break, BX/BM, and BzK selection) simultaneously in the Subaru Deep Field. This field has reliable (Δz/(1 + z) = 0.02--0.09) photometric redshifts for ~53,000 galaxies from 20 bands (1500Å--2.2μm). The BzK, LBG, and BX/BM samples suffer contamination from z<1 interlopers of 6%, 8%, and 20%, respectively. Around the redshifts where it is most sensitive (z~1.9 for star-forming BzK, z~1.8 for z~2 LBGs, z~1.6 for BM, and z~2.3 for BX), each technique finds 60-80% of the census of the three methods. In addition, each of the color techniques shares 75-96% of its galaxies with another method, which is consistent with previous studies that adopt identical criteria on magnitudes and colors. Combining the three samples gives a comprehensive census that includes ~90% of z-phot = 1-3 galaxies, using standard magnitude limits similar to previous studies. In fact, we find that among z = 1-2.5 galaxies in the color selection census, 81-90% of them can be selected by just combining the BzK selection with one of the UV techniques (z~2 LBG or BX and BM). The average galaxy stellar mass, reddening and SFRs all decrease systematically from the sBzK population to the LBGs, and to the BX/BMs. The combined color selections yield a total cosmic SFR density of 0.18 $\pm$ 0.03 M_sun yr^{-1} Mpc^{-3} for K_AB <= 24. We find that 65% of the star formation is in galaxies with E(B-V) > 0.25 mag, even though they are only one-fourth of the census by number.

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arXiv2011

Completing the Census of Ly-alpha Emitters at the Reionization Epoch

We carried out extended spectroscopic confirmations of Ly-alpha emitters (LAEs) at z=6.5 and 5.7 in the Subaru Deep Field. Now, the total number of spectroscopically confirmed LAEs is 45 and 54 at z=6.5 and 5.7, respectively, and at least 81% (70%) of our photometric candidates at z=6.5 (5.7) have been spectroscopically identified as real LAEs. We made careful measurements of the Ly-alpha luminosity, both photometrically and spectroscopically, to accurately determine the Ly-alpha and rest-UV luminosity functions (LFs). The substantially improved evaluation of the Ly-alpha LF at z=6.5 shows an apparent deficit from z=5.7 at least at the bright end, and a possible decline even at the faint end, though small uncertainties remain. The rest-UV LFs at z=6.5 and 5.7 are in good agreement, at least at the bright end, in clear contrast to the differences seen in the Ly-alpha LF. These results imply an increase in the neutral fraction of the intergalactic medium from z=5.7 to 6.5. The rest-frame equivalent width (EW_0) distribution at z=6.5 seems to be systematically smaller than z=5.7, and it shows an extended tail toward larger EW_0. The bright end of the rest-UV LF can be reproduced from the observed Ly-alpha LF and a reasonable EW_0-UV luminosity relation. Integrating this rest-UV LF provides the first measurement of the contribution of LAEs to the photon budget required for reionization. The derived UV LF suggests that the fractional contribution of LAEs to the photon budget among Lyman break galaxies significantly increases towards faint magnitudes. Low-luminosity LAEs could dominate the ionizing photon budget, though this inference depends strongly on the uncertain faint-end slope of the Ly-alpha LF.

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arXiv2011

The Mass of the Black Hole in Arp 151 from Bayesian Modeling of Reverberation Mapping Data

Supermassive black holes are believed to be ubiquitous at the centers of galaxies. Measuring their masses is extremely challenging yet essential for understanding their role in the formation and evolution of cosmic structure. We present a direct measurement of the mass of a black hole in an active galactic nucleus (Arp 151) based on the motion of the gas responsible for the broad emission lines. By analyzing and modeling spectroscopic and photometric time series, we find that the gas is well described by a disk or torus with an average radius of 3.99 +- 1.25 light days and an opening angle of 68.9 (+21.4, -17.2) degrees, viewed at an inclination angle of 67.8 +- 7.8 degrees (that is, closer to face-on than edge-on). The black hole mass is inferred to be 10^(6.51 +- 0.28) solar masses. The method is fully general and can be used to determine the masses of black holes at arbitrary distances, enabling studies of their evolution over cosmic time.

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arXiv2011

A Local Baseline of the Black Hole Mass Scaling Relations for Active Galaxies. I. Methodology and Results of Pilot Study

We present high-quality Keck/LRIS longslit spectroscopy of a pilot sample of 25 local active galaxies selected from the SDSS (0.02 10^7 M_sun) to study the relations between black hole mass (MBH) and host-galaxy properties. We determine stellar kinematics of the host galaxy, deriving stellar-velocity dispersion profiles and rotation curves from three spectral regions (including CaH&K, MgIb triplet, and CaII triplet). In addition, we perform surface photometry on SDSS images, using a newly developed code for joint multi-band analysis. BH masses are estimated from the width of the Hbeta emission line and the host-galaxy free 5100A AGN luminosity. Combining results from spectroscopy and imaging allows us to study four MBH scaling relations: MBH-sigma, MBH-L(sph), MBH-M(sph,*), MBH-M(sph,dyn). We find the following results. First, stellar-velocity dispersions determined from aperture spectra (e.g. SDSS fiber spectra or unresolved data from distant galaxies) can be biased, depending on aperture size, AGN contamination, and host-galaxy morphology. However, such a bias cannot explain the offset seen in the MBH-sigma relation at higher redshifts. Second, while the CaT region is the cleanest to determine stellar-velocity dispersions, both the MgIb region, corrected for FeII emission, and the CaHK region, although often swamped by the AGN powerlaw continuum and emission lines, can give results accurate to within a few percent. Third, the MBH scaling relations of our pilot sample agree in slope and scatter with those of other local active and inactive galaxies. In the next papers of the series we will quantify the scaling relations, exploiting the full sample of ~100 objects.

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