Edward A. Ajhar

National Optical Astronomy Observatory, Tucson, Arizona, United States

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Publications (55)182.73 Total impact

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    ABSTRACT: Hubble Space Telescope WFPC2 images show that the low-luminosity elliptical galaxy companion to M87, NGC 4486B, has a double nucleus that resembles the one discovered in M31. The NGC 4486B nucleus comprises two peaks separated by ~015 or 12 pc. Neither peak is coincident with the galaxy photocenter, which falls between them. The nuclear morphology is independent of color; thus, the double structure is not likely to arise from dust absorption. It is also unlikely that the peaks are a binary stellar system (such as an ongoing merger of the nucleus of a less luminous system with the nucleus of NGC 4486B), since the decay timescale is short ( < 108 yr) and the present environment of NGC 4486B should inhibit mergers. We suggest that the nuclear morphology of NGC 4486B may be explained by the eccentric-disk model of Tremaine, which was originally advanced to account for the central structure of M31. This model requires that NGC 4486B contains a central massive dark object, which is suggested by the spectroscopic observations of Kormendy et al. The eccentric disk might be related to the symmetric disk seen at larger radii.
    The Astrophysical Journal 01/2009; 471(2):L79. · 6.73 Impact Factor
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    ABSTRACT: Using published photometry and spectroscopy, we construct the fundamental plane and Dn-σ relations in Leo I, Virgo, and Fornax. The published Cepheid period-luminosity (PL) relations to spirals in these clusters fixes the relation between angular size and metric distance for both the fundamental plane and Dn-σ relations. Using the locally calibrated fundamental plane, we infer distances to a sample of clusters with a mean redshift of cz ≈ 6000 km s-1, and derive a value of H0 = 78 ± 5 ± 9 km s-1 Mpc-1 (random and systematic errors, respectively) for the local expansion rate. This value includes a correction for depth effects in the Cepheid distances to the nearby clusters, which decreased the deduced value of the expansion rate by 5% ± 5%. If one further adopts the metallicity correction to the Cepheid PL relation as derived by the Key Project, the value of the Hubble constant would decrease by a further 6% ± 4%. These two sources of systematic error, when combined with a ±6% error due to the uncertainty in the distance to the Large Magellanic Cloud, a ±4% error due to uncertainties in the WFPC2 calibration, and several small sources of uncertainty in the fundamental plane analysis, yield a total systematic uncertainty of ±11%. We find that the values obtained using either the cosmic microwave background (CMB) or a flow-field model, for the reference frame of the distant clusters, agree to within 1%. The Dn-σ relation also produces similar results, as expected from the correlated nature of the two scaling relations. A complete discussion of the sources of random and systematic error in this determination of the Hubble constant is also given, in order to facilitate comparison with the other secondary indicators being used by the Key Project.
    The Astrophysical Journal 12/2008; 529(2):768. · 6.73 Impact Factor
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    ABSTRACT: We present results from the Surface Brightness Fluctuation (SBF) Survey for the distances to 300 early-type galaxies, of which approximately half are ellipticals. A modest change in the zero point of the SBF relation, derived by using Cepheid distances to spirals with SBF measurements, yields a Hubble constant H0 = 77 ± 4 ± 7 km s-1 Mpc-1, somewhat larger than the HST Key Project result. We discuss how this difference arises from a different choice of zero point, a larger sample of galaxies, and a different model for large-scale flows. Our result is 4% larger than found in a recent comparison of the SBF Survey peculiar velocities with predictions derived from the galaxy density field measured by redshift surveys (Blakeslee et al. 1999b). The zero point of the SBF relation is the largest source of uncertainty, and our value for H0 is subject to all the systematic uncertainties of the Key Project zero point, including a 5% decrease if a metallicity correction for the Cepheids is adopted. To analyze local and large-scale flows—departures from smooth Hubble flow—we use a parametric model for the distribution function of mean velocity and velocity dispersion at each point in space. These models include a uniform thermal velocity dispersion and spherical attractors whose position, amplitude, and radial shape are free to vary. Our modeling procedure performs a maximum likelihood fit of the model to the observations. Our models rule out a uniform Hubble flow as an acceptable fit to the data. Inclusion of two attractors, one of which having a best-fit location coincident with the Virgo cluster and the other having a fit location slightly beyond the Centaurus clusters (which we refer to by convention as the Great Attractor), reduces χ2/N from 2.1 to 1.1. The fits to these attractors both have radial profiles such that v ≈ r-1 (i.e., isothermal) over a range of overdensity between about 10 and 1, but fall off more steeply at larger radius. The best-fit value for the small-scale, cosmic thermal velocity is 180 ± 14 km s-1. The quality of the fit can be further improved by the addition of a quadrupole correction to the Hubble flow. The dipole velocity offset from the CMB frame for the volume we survey (amplitude ~150 km s-1) and the quadrupole may be genuine (though weak) manifestations of more distant density fluctuations, but we find evidence that they are more likely due to the inadequacy of spherical models to describe the density profile of the attractors. The residual dipole we find is comparable to the systematic error in these simple, parametrized models; in other words, our survey volume of R < 3000 km s-1 is, in a mass averaged sense, essentially at rest with respect to the CMB. This contradicts claims of large amplitude flows in much larger volumes that include our sample. Our best-fitting model, which uses attenuated power-law mass distributions for the two attractors, has enclosed mass overdensities at the Local Group of 7 × 1014 M☉ for the Virgo Attractor and 9 × 1015 M☉ for the Great Attractor. Without recourse to information about the overdensities of these attractors with respect to the cosmic mean we cannot provide a good constraint on ΩM, but our data do give us accurate measurements in terms of δ, the overdensities of the enclosed masses with respect to the background: δ Ω = 0.33 for the Virgo Attractor and δ Ω = 0.27 for the Great Attractor.
    The Astrophysical Journal 12/2008; 530(2):625. · 6.73 Impact Factor
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    ABSTRACT: We measured infrared surface brightness fluctuation (SBF) distances to an isotropically distributed sample of 16 distant galaxies with redshifts reaching 10,000 km s-1 using the near-IR camera and multiobject spectrometer (NICMOS) on the Hubble Space Telescope (HST). The excellent spatial resolution, very low background, and brightness of the IR fluctuations yielded the most distant SBF measurements to date. Twelve nearby galaxies were also observed and used to calibrate the F160W (1.6 μm) SBF distance scale. Of these, three have Cepheid variable star distances measured with HST and eleven have optical I-band SBF distance measurements. A distance modulus of 18.5 mag to the Large Magellanic Cloud was adopted for this calibration. We present the F160W SBF Hubble diagram and find a Hubble constant H0 = 76 ± 1.3 (1 σ statistical) ±6 (systematic) km s-1 Mpc-1. This result is insensitive to the velocity model used to correct for local bulk motions. Restricting the fit to the six most distant galaxies yields the smallest value of H0 = 72 ± 2.3 km s-1 Mpc-1 that is consistent with the data. This 6% decrease in the Hubble constant is consistent with the hypothesis that the Local Group inhabits an underdense region of the universe, but is also consistent with the best-fit value of H0 = 76 km s-1 Mpc-1 at the 1.5 σ level.
    The Astrophysical Journal 12/2008; 550(2):503. · 6.73 Impact Factor
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    ABSTRACT: To empirically calibrate the IR surface brightness fluctuation (SBF) distance scale and probe the properties of unresolved stellar populations, we measured fluctuations in 65 galaxies using NICMOS on the Hubble Space Telescope. The early-type galaxies in this sample include elliptical and S0 galaxies and spiral bulges in a variety of environments. Absolute fluctuation magnitudes in the F160W (1.6 μm) filter (F160W) were derived for each galaxy using previously measured I-band SBF and Cepheid variable star distances. F160W SBFs can be used to measure distances to early-type galaxies with a relative accuracy of ~10%, provided that the galaxy color is known to ~0.035 mag or better. Near-IR fluctuations can also reveal the properties of the most luminous stellar populations in galaxies. Comparison of F160W fluctuation magnitudes and optical colors to stellar population model predictions suggests that bluer elliptical and S0 galaxies have significantly younger populations than redder ones and may also be more metal-rich. There are no galaxies in this sample with fluctuation magnitudes consistent with old, metal-poor (t > 5 Gyr, [Fe/H] < -0.7) stellar population models. Composite stellar population models imply that bright fluctuations in the bluer galaxies may be the result of an episode of recent star formation in a fraction of the total mass of a galaxy. Age estimates from the F160W fluctuation magnitudes are consistent with those measured using the Hβ Balmer-line index. The two types of measurements make use of completely different techniques and are sensitive to stars in different evolutionary phases. Both techniques reveal the presence of intermediate-age stars in the early-type galaxies of this sample.
    The Astrophysical Journal 12/2008; 583(2):712. · 6.73 Impact Factor
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    ABSTRACT: We present Hubble Space Telescope measurements of surface brightness fluctuation (SBF) distances to early-type galaxies that have hosted Type Ia supernovae (SNe Ia). The agreement in the relative SBF and SN Ia multicolor light-curve shape and delta-m15 distances is excellent. There is no systematic scale error with distance, and previous work has shown that SBFs and SNe Ia give consistent ties to the Hubble flow. However, we confirm a systematic offset of ~0.25 mag in the distance zero points of the two methods, and we trace this offset to their respective Cepheid calibrations. SBFs have in the past been calibrated with Cepheid distances from the H0 Key Project team, while SNe Ia have been calibrated with Cepheid distances from the team composed of Sandage, Saha, and collaborators. When the two methods are calibrated in a consistent way, their distances are in superb agreement. Until the conflict over the "long" and "short" extragalactic Cepheid distances among many galaxies is resolved, we cannot definitively constrain the Hubble constant to better than ~10%, even leaving aside the additional uncertainty in the distance to the Large Magellanic Cloud, common to both Cepheid scales. However, recent theoretical SBF predictions from stellar population models favor the Key Project Cepheid scale, while the theoretical SN Ia calibration lies between the long and short scales. In addition, while the current SBF distance to M31/M32 is in good agreement with the RR Lyrae and red giant branch distances, calibrating SBFs with the longer Cepheid scale would introduce a 0.3 mag offset with respect to the RR Lyrae scale.
    The Astrophysical Journal 12/2008; 559(2):584. · 6.73 Impact Factor
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    ABSTRACT: We report data for I-band surface brightness fluctuation (SBF) magnitudes, (V-I) colors, and distance moduli for 300 galaxies. The survey contains E, S0, and early-type spiral galaxies in the proportions of 49 : 42 : 9 and is essentially complete for E galaxies to Hubble velocities of 2000 km s-1, with a substantial sampling of E galaxies out to 4000 km s-1. The median error in distance modulus is 0.22 mag. We also present two new results from the survey. (1) We compare the mean peculiar flow velocity (bulk flow) implied by our distances with predictions of typical cold dark matter transfer functions as a function of scale, and we find very good agreement with cold, dark matter cosmologies if the transfer function scale parameter Γ and the power spectrum normalization σ8 are related by σ8Γ-0.5 ≈ 2 ± 0.5. Derived directly from velocities, this result is independent of the distribution of galaxies or models for biasing. This modest bulk flow contradicts reports of large-scale, large-amplitude flows in the ~200 Mpc diameter volume surrounding our survey volume. (2) We present a distance-independent measure of absolute galaxy luminosity, and show how it correlates with galaxy properties such as color and velocity dispersion, demonstrating its utility for measuring galaxy distances through large and unknown extinction.
    The Astrophysical Journal 12/2008; 546(2):681. · 6.73 Impact Factor
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    ABSTRACT: We present observations of 77 early-type galaxies imaged with the PC1 CCD of the Hubble Space Telescope (HST) WFPC2. "Nuker-law" parametric fits to the surface brightness profiles are used to classify the central structure into "core" or "power-law" forms. Core galaxies are typically rounder than power-law galaxies. Nearly all power-law galaxies with central ellipticities ≥ 0.3 have stellar disks, implying that disks are present in power-law galaxies with < 0.3 but are not visible because of unfavorable geometry. A few low-luminosity flattened core galaxies also have disks; these may be transition forms from power-law galaxies to more luminous core galaxies, which lack disks. Several core galaxies have strong isophote twists interior to their break radii, although power-law galaxies have interior twists of similar physical significance when the photometric perturbations implied by the twists are evaluated. Central color gradients are typically consistent with the envelope gradients; core galaxies have somewhat weaker color gradients than power-law galaxies. Nuclei are found in 29% of the core galaxies and 60% of the power-law galaxies. Nuclei are typically bluer than the surrounding galaxy. While some nuclei are associated with active galactic nuclei (AGNs), just as many are not; conversely, not all galaxies known to have a low-level AGN exhibit detectable nuclei in the broadband filters. NGC 4073 and 4382 are found to have central minima in their intrinsic starlight distributions; NGC 4382 resembles the double nucleus of M31. In general, the peak brightness location is coincident with the photocenter of the core to a typical physical scale of <1 pc. Five galaxies, however, have centers significantly displaced from their surrounding cores; these may be unresolved asymmetric double nuclei. Finally, as noted by previous authors, central dust is visible in about half of the galaxies. The presence and strength of dust correlates with nuclear emission; thus, dust may outline gas that is falling into the central black hole. The prevalence of dust and its morphology suggest that dust clouds form, settle to the center, and disappear repeatedly on ~108 yr timescales. We discuss the hypothesis that cores are created by the decay of a massive black hole binary formed in a merger. Apart from their brightness profiles, there are no strong differences between core galaxies and power-law galaxies that demand this scenario; however, the rounder shapes of core, their lack of disks, and their reduced color gradients may be consistent with it.
    The Astronomical Journal 12/2007; 129(5):2138. · 4.97 Impact Factor
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    ABSTRACT: We fit axisymmetric three-integral dynamical models to NGC 3379 using the line-of-sight velocity distribution obtained from Hubble Space Telescope FOS spectra of the galaxy center and ground-based long-slit spectroscopy along four position angles, with the light distribution constrained by WFPC2 and ground-based images. We have fitted models with inclinations from 29° (intrinsic galaxy type E5) to 90° (intrinsic E1) and black hole masses from 0 to 109 M. The best-fit black hole masses range from 6 × 107 to 2 × 108 M, depending on inclination. The preferred inclination is 90° (edge-on); however, the constraints on allowed inclination are not very strong, owing to our assumption of constant M/LV. The velocity ellipsoid of the best model is not consistent with either isotropy or a two-integral distribution function. Along the major axis, the velocity ellipsoid becomes tangential at the innermost bin, radial in the midrange radii, and tangential again at the outermost bins. The rotation rises quickly at small radii owing to the presence of the black hole. For the acceptable models, the radial-to-tangential [(σ + σ)/2] dispersion in the midrange radii ranges over 1.1 < σr/σt < 1.7, with the smaller black holes requiring larger radial anisotropy. Compared with these three-integral models, two-integral isotropic models overestimate the black hole mass since they cannot provide adequate radial motion. However, the models presented in this paper still contain restrictive assumptions—namely, assumptions of constant M/LV and spheroidal symmetry—requiring yet more models to study black hole properties in complete generality.
    The Astronomical Journal 12/2007; 119(3):1157. · 4.97 Impact Factor
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    ABSTRACT: The recently completed I-band Surface Brightness Fluctuations (SBF) Survey of Galaxy Distances includes high-quality distance measurements to nearly 300 early-type galaxies within 4000 km/s. We compare the peculiar velocities observed in this survey with those predicted from the galaxy density field found in flux-limited redshift surveys. Using linear gravitational instability theory and the IRAS flux-limited redshift survey, we constrain the parameter β = Ω0.6/b, where b is the linear biasing factor of the galaxies, to be β = 0.44 ± 0.08. The analysis also produces a value for the thermal velocity dispersion of the non-cluster galaxies in this sample, which we find to be about 180 km/s, and for the peculiar motion of about 150 km/s of the Local Group with respect to the mean local velocity field. We have also explored nonlinear gravitational models, which allow for independent constraints on Ω and the galaxy bias on scales of ~300 km/s. We discuss the latest results from this analysis.
    Proceedings of the International Astronomical Union 01/2005; 201:439.
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    ABSTRACT: We examine the use of surface brightness fluctuations (SBF) for both stellar population and distance studies. New V-band SBF data are reported for five Fornax cluster galaxies and combined with literature data to define a new V-band SBF distance indicator. We use new stellar population models, based on the latest Padua isochrones transformed empirically to the observational plane, to predict SBF magnitudes and integrated colours for a wide range of population ages and metallicities. We examine the sensitivity of the predictions to changes in the isochrones, transformations, and IMF. The new models reproduce the SBF data for globular clusters fairly well, especially if higher metallicity globulars are younger. The models also give a good match to the "fluctuation colors" of elliptical galaxies. In order to obtain theoretical calibrations of the SBF distance indicators, we combine our single-burst models into composite population models. These models reproduce the observed behavior of the SBF magnitudes as a function of stellar population parameters, including the steep colour dependence found for HST/WFPC2 F814W SBF data. Because the theoretical SBF calibrations are fairly sensitive to uncertain details of stellar evolution, the empirical calibrations are more secure. However, the sensitivity of SBF to these finer details potentially makes it a powerful constraint for stellar evolution and population synthesis. [abbridged] Comment: 24 pages with 17 embedded figures. MNRAS, in press
    Monthly Notices of the Royal Astronomical Society 08/2000; · 5.52 Impact Factor
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    01/2000; 201:70.
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    ABSTRACT: We compare the predicted local peculiar velocity field from the IRAS 1.2 Jy flux-limited redshift survey and the Optical Redshift Survey (ORS) to the measured peculiar velocities from the recently completed SBF Survey of Galaxy Distances. The analysis produces a value of \beta = \Omega^{0.6}/b for the redshift surveys, where b is the linear biasing factor, and a tie to the Hubble flow, i.e., a value of H_0, for the SBF Survey. There is covariance between these parameters, but we find good fits with H_0 \approx 74 \kmsM for the SBF distances, \beta_I \approx 0.44 for the IRAS survey predictions, and \beta_O \approx 0.3 for the ORS. The small-scale velocity error \sigv \sim 200 \kms is similar to, though slightly larger than, the value obtained in our parametric flow modeling with SBF.
    11/1999;
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    ABSTRACT: Surface Brightness Fluctuation (SBF) has proven to be an effective means to measure the distances of relatively nearby (5--10,000 km/s), early-type galaxies. SBF offers an unusual combination of high accuracy and plentiful measurements in the crucial distance range where Cepheids can be measured out to the Hubble flow, and is also promising for theoretical calibration from first principles using stellar populations. I will review the current status of SBF measurements, describe our calibration of the SBF zeropoint and the Hubble constant we derive, discuss possible systematic errors and remedies, and relate ongoing and future work with SBF which is relevant to the expansion of the universe.
    05/1999;
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    ABSTRACT: We measured IR surface brightness fluctuation (SBF) distances for an isotropically distributed set of 12 brightest cluster galaxies with distances reaching 10,000 km/s using the near-IR camera and multi-object spectrometer (NICMOS) on the Hubble Space Telescope (HST). The excellent resolution using NICMOS and brightness of the IR fluctuations allowed us to make the most distant SBF measurements to date. Ten galaxies in clusters with HST Cepheid distances were observed to calibrate the SBF distance scale in the F160W (1.6 micron) filter. Fourteen galaxies have I-band SBF distance measurements and provide another calibration of the IR distances. We present the F160W SBF Hubble diagram and compare the distances measured using the Cepheid and I-band SBF calibrations to each other and to theoretical stellar population models for the purpose of determining the Hubble constant on scales in excess of 100 Mpc. The sample of galaxies was chosen to minimize sensitivity to local bulk motions, and we estimate their influence on the current result.
    05/1999;
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    ABSTRACT: We compare the peculiar velocities measured in the surface brightness fluctuation survey of galaxy distances with the predictions from the density fields of the IRAS 1.2 Jy flux-limited redshift survey and the optical redshift survey (ORS) to derive simultaneous constraints on the Hubble constant H0 and the density parameter β = Ω0.6/b, where b is the linear bias. We find that βI = 0.42 and βO = 0.26 ± 0.08 for the IRAS and ORS comparisons, respectively, and that H0 = 74 ± 4 km s-1 Mpc (with an additional 9% uncertainty due to the Cepheids themselves). The match between predicted and observed peculiar velocities is good for these values of H0 and β, and although there is covariance between the two parameters, our results clearly point toward low-density cosmologies. Thus, the unresolved discrepancy between the "velocity-velocity" and "density-density" measurements of β continues.
    The Astrophysical Journal 01/1999; 527(2). · 6.73 Impact Factor
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    ABSTRACT: this paper, it is likely that the MDO is a supermassive black hole (MBH), but in only a few cases have plausible alternatives to a black hole been ruled out. These are important as they establish the reality of MBH and justify the interpretation of less compelling objects as MBHs.
    11/1998;
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    Article: M32 ± 1***
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    ABSTRACT: Multicolor HST WFPC2 images are used to study the central structure of the three Local Group galaxies M31, M32, and M33. PSF deconvolution and modeling of image aliasing are required to recover accurate brightness profiles within r < 05. The data present a study in contrasts that suggests different evolutionary histories. In M31, the nucleus is double-peaked, as found by WFPC1 and confirmed by WFPC2. The dimmer peak, P2, is closely centered on the bulge isophotes to 01, implying that it is the dynamical center of the galaxy. Directly on P2 lies a UV-bright compact source that was discovered by King, Stanford, & Crane at 1700 Å. WFPC2 images now show that this source is resolved, with r1/2 ≈ 0.2 pc. It dominates the nucleus at 3000 Å, and its spectral energy distribution is consistent with late B–early A stars. This probable nuclear star cluster may consist of young stars and be an older version of the central cluster of hot stars that now sits at the center of the Milky Way, or it may consist of heavier stars built up from collisions in a possible cold disk of stars orbiting P2. Aspects of its formation remain highly problematic. In M32, new images show that the central cusp continues to rise into the HST limit with slope γ ≈ 0.5 and the central density ρ0 > 107M⊙ pc-3. The V-I and U-V color profiles are essentially flat, and there is no sign of an inner disk, dust, or any other structure. This total lack of features seems at variance with a nominal stellar collision time of 2 × 1010 yr, which implies that a significant fraction of the light in the central pixel should come from blue stragglers. This discrepancy is eased but not completely removed if the stellar population is young (2 × 109 yr). The stubborn normalcy of M32 at tiny radii may be emerging as an important puzzle. In M33, the nucleus has an extremely steep γ = 1.49 power-law profile for 005 < r < 02 that appears to become somewhat shallower as the HST resolution limit is approached. The profile for r < 004 can be described as having either a γ ≈ 0.8 cusp or a small core with rc ≈ 0.13 pc. The central density is ρ0 > 2 × 106M⊙ pc-3, and the implied central relaxation time is only ~3 × 106 yr, indicating that the nucleus is highly relaxed. The accompanying short collision time of 7 × 109 yr predicts a central blue straggler component that is quantitatively consistent with the strong V-I and B-R color gradients seen with HST and from the ground. When combined with the Galaxy, the nuclei of the Local Group show surprisingly similar radial density profiles but divide into two classes according to velocity dispersion and black hole content: M31, M32, and the Milky Way are dominated dynamically (and stabilized against relaxation) by massive central black holes, while M33 lacks a dominant black hole. An obvious hypothesis is that a sizable stellar spheroid (which M33 lacks) is necessary to grow a massive black hole. A further implication is that the black hole growth in M31, M32, and the Milky Way was accompanied by evolution in the stellar density profiles, stellar populations, and dynamical structure of these nuclei such that their past appearance may have differed significantly from what they look like today. In short, HST observations are taking us to scales where understanding the central structure of galactic nuclei is intimately connected to the detailed interactions among their central stellar populations.
    The Astronomical Journal 11/1998; 116(5):2263. · 4.97 Impact Factor
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    ABSTRACT: Black holes, an extreme consequence of the mathematics of General Relativity, have long been suspected of being the prime movers of quasars, which emit more energy than any other objects in the Universe. Recent evidence indicates that supermassive black holes, which are probably quasar remnants, reside at the centers of most galaxies. As our knowledge of the demographics of these relics of a violent earlier Universe improve, we see tantalizing clues that they participated intimately in the formation of galaxies and have strongly influenced their present-day structure.
    Nature 10/1998; · 38.60 Impact Factor
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    John P. Blakeslee, Edward A. Ajhar, John L. Tonry
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    ABSTRACT: The practice of measuring galaxy distances from their spatial fluctuations in surface brightness is now a decade old. While several past articles have included some review material, this is the first intended as a comprehensive review of the surface brightness fluctuation (SBF) method. The method is conceptually quite simple, the basic idea being that nearby (but unresolved) star clusters and galaxies appear "bumpy", while more distant ones appear smooth. This is quantified via a measurement of the amplitude of the Poisson fluctuations in the number of unresolved stars encompassed by a CCD pixel (usually in an image of an elliptical galaxy). Here, we describe the technical details and difficulties involved in making SBF measurements, discuss theoretical and empirical calibrations of the method, and review the numerous applications of the method from the ground and space, in the optical and near-infrared. We include discussions of stellar population effects and the "universality" of the SBF standard candle. A final section considers the future of the method.
    08/1998;

Publication Stats

3k Citations
182.73 Total Impact Points

Institutions

  • 1994–2009
    • National Optical Astronomy Observatory
      Tucson, Arizona, United States
  • 2008
    • University of Miami
      • Department of Physics
      Coral Gables, FL, United States
  • 2007
    • Saint Thomas University
      Miami Gardens, Florida, United States
  • 1996
    • Massachusetts Institute of Technology
      • Department of Physics
      Cambridge, Massachusetts, United States