Surface Brightness Fluctuation Distance Measurements Research Articles

Infrared Surface Brightness Fluctuation Distances for MASSIVE and Type Ia Supernova Host Galaxies*

Abstract We measured high-quality surface brightness fluctuation (SBF) distances for a sample of 63 massive early-type galaxies using the WFC3/IR camera on the Hubble Space Telescope. The median uncertainty on the SBF distance measurements is 0.085 mag, or 3.9% in distance. Achieving this precision at distances of 50–100 Mpc required significant improvements to the SBF calibration and data analysis procedures for WFC3/IR data. Forty-two of the galaxies are from the MASSIVE Galaxy Survey, a complete sample of massive galaxies within ∼100 Mpc; the SBF distances for these will be used to improve the estimates of the stellar and central supermassive black hole masses in these galaxies. Twenty-four of the galaxies are Type Ia supernova hosts, useful for calibrating SN Ia distances for early-type galaxies and exploring possible systematic trends in the peak luminosities. Our results demonstrate that the SBF method is a powerful and versatile technique for measuring distances to galaxies with evolved stellar populations out to 100 Mpc and constraining the local value of the Hubble constant.

A new measurement of the Hubble constant using Type Ia supernovae calibrated with surface brightness fluctuations

We present a new calibration of the peak absolute magnitude of Type Ia supernovae (SNe Ia) based on the surface brightness fluctuations (SBF) method, aimed at measuring the value of the Hubble constant. We build a sample of calibrating anchors consisting of 24 SNe hosted in galaxies that have SBF distance measurements. Applying a hierarchical Bayesian approach, we calibrate the SN Ia peak luminosity and extend the Hubble diagram into the Hubble flow by using a sample of 96 SNe Ia in the redshift range 0.02 < z < 0.075, which was extracted from the Combined Pantheon Sample. We estimate a value of H0 = 70.50 ± 2.37 (stat.) ± 3.38 (sys.) km s−1 Mpc−1 (i.e., 3.4% stat., 4.8% sys.), which is in agreement with the value obtained using the tip of the red giant branch calibration. It is also consistent, within errors, with the value obtained from SNe Ia calibrated with Cepheids or the value inferred from the analysis of the cosmic microwave background. We find that the SNe Ia distance moduli calibrated with SBF are on average larger by 0.07 mag than those calibrated with Cepheids. Our results point to possible differences among SNe in different types of galaxies, which could originate from different local environments and/or progenitor properties of SNe Ia. Sampling different host galaxy types, SBF offers a complementary approach to using Cepheids, which is important in addressing possible systematics. As the SBF method has the ability to reach larger distances than Cepheids, the impending entry of the Vera C. Rubin Observatory and JWST into operation will increase the number of SNe Ia hosted in galaxies where SBF distances can be measured, making SBF measurements attractive for improving the calibration of SNe Ia, as well as in the estimation of H0.

SURFACE BRIGHTNESS FLUCTUATIONS IN THEHUBBLE SPACE TELESCOPEACS/WFC F814W BANDPASS AND AN UPDATE ON GALAXY DISTANCES

We measure surface brightness fluctuation (SBF) magnitudes in the F814W filter and g-I colors for nine bright early-type Fornax cluster galaxies imaged with the Hubble Space Telescope Advanced Camera for Surveys (ACS). The goal is to achieve the first systematic SBF calibration for the ACS/F814W bandpass. Because of its much higher throughput, F814W is more efficient for SBF studies of distant galaxies than the ACS/F850LP bandpass that has been used to study nearby systems. Over the color range spanned by the sample galaxies, 1.06<g-I<1.32 (AB mag), the dependence of SBF magnitude mbar_I on g-I is linear to a good approximation, with slope $\sim2$. When the F850LP SBF distance measurements from the ACS Fornax Cluster Survey are used to derive absolute Mbar_I magnitudes, the dependence on g-I becomes extremely tight, with a slope of $1.8\pm0.2$ and scatter of 0.03 mag. The small observed scatter indicates both that the estimated random errors are correct, and that the intrinsic deviations from the SBF-color relation are strongly correlated between the F814W and F850LP bandpasses, as expected. The agreement with predictions from stellar population models is good, both in slope and zero point, indicating that our mean Fornax distance of 20 Mpc is accurate. The models predict curvature in the relation beyond the color limits of our sample; thus, the linear calibration should not be extrapolated naively. In the Appendices, we reconsider the Tonry ground-based and Jensen NICMOS SBF distance catalogues; we provide a correction formula to ameliorate the small apparent bias in the former, and the offset needed to make the latter consistent with other SBF studies. We also tabulate two new SBF distances to galaxies observed in the ACS Virgo Cluster Survey.

Luminosity Indicators in the Ultraviolet Spectra of Type Ia Supernovae

We present a complete sample of International Ultraviolet Explorer and Hubble Space Telescope ultraviolet (UV) spectra of Type Ia supernovae (SNe Ia) through 2004. We measure the equivalent width (EW) and blueshifted velocity of the minimum of the one strong UV feature, Fe II λ3250. We also quantify the slope of the near-UV spectra using a new parameter, the "UV ratio." We find that the velocity of the Fe II line does not correlate with light-curve shape, while the EW shows distinct behavior for the slow- and fast-declining objects. Using precise Cepheid and surface brightness fluctuation distance measurements of six objects with UV spectra observed near maximum light (a total of 12 spectra), we determine that the UV ratio at maximum light is highly correlated with SN Ia luminosity. A larger sample of UV spectra is necessary to determine the validity of these luminosity indicators and whether they can be combined with light-curve shape to improve measured SN Ia distances.

H0 measurement from VLT deep I–band surface brightness fluctuations in NGC 564 and NGC 7619

We have measured the Hubble constant H 0 in NGC 564 at km s-1 and in NGC 7619 at km s-1 with deep I –band Surface Brightness Fluctuation distance measurements at the ESO Very Large Telescope (VLT). We obtain km s-1 /Mpc for NGC 564 and for NGC 7619. The actual SBF sample used for the measurement of H 0 in the Hubble Space Telescope Key Project on the Extragalactic Distance Scale (Freedman et al. 2001) amounts to six galaxies. When we combine the measurements from this work with our previous VLT I –band SBF distance measurement in IC 4296 (Mei et al. 2000), we obtain: H 0 = 68 ± 5 ± 6 km s-1 /Mpc. When we add the Freedman et al. (2001) SBF sample, we obtain km s-1 /Mpc.

Planetary Nebulae as Standard Candles. XII. Connecting the Population I and Population II Distance Scales

We report the results of [O III] λ5007 surveys for planetary nebulae (PNe) in six galaxies: NGC 2403, NGC 3115, NGC 3351, NGC 3627, NGC 4258, and NGC 5866. Using on-band/off-band [O III] λ5007 images, as well as images taken in Hα, we identify samples of PNe in these galaxies and derive their distances using the planetary nebula luminosity function (PNLF). We then combine these measurements with previous data to compare the PNLF, Cepheid, and surface brightness fluctuation (SBF) distance scales. We use a sample of 13 galaxies to show that the absolute magnitude of the PNLF cutoff is fainter in small, low-metallicity systems, but the trend is well modeled by the theoretical relation of Dopita, Jacoby, & Vassiliadis. When this metallicity dependence is removed, the scatter between the Cepheid and PNLF distances becomes consistent with the internal errors of the methods and independent of any obvious galaxy parameter. We then use these data to recalibrate the zero point of the PNLF distance scale. We use a sample of 28 galaxies to show that the scatter between the PNLF and SBF distance measurements agrees with that predicted from the techniques' internal errors and that there is no systematic trend between the distance residuals and stellar population. However, we also find that the PNLF and SBF methods have a significant scale offset: Cepheid-calibrated PNLF distances are, on average, ~0.3 mag smaller than Cepheid-calibrated SBF distances. We discuss the possible causes of this offset and suggest that internal extinction in the bulges of the SBF calibration galaxies is the principal cause of the discrepancy. If this hypothesis is correct, then the SBF-based Hubble constant must be increased by ~7%. We also use our distance to NGC 4258 to argue that the short distance scale to the LMC is correct and that the global Hubble constant inferred from the Hubble Space Telescope Key Project should be increased by 8% ± 3% to H0 = 78 ± 7 km s-1 Mpc-1.

The Infrared Surface Brightness Fluctuation Hubble Constant

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.

Anomalous surface brightness fluctuations in NGC 4489

Anomalously high K -band surface brightness fluctuations (SBF) have been reported in NGC 4489 by Pahre & Mould ([CITE]), Jensen et al. ([CITE]) and Jensen et al. ([CITE]). However, these conclusions were uncertain because of relatively low signal-to-noise data. New high signal-to-noise data for NGC 4489 have been obtained at the NOAO/KPNO 2.1 m and the ESO/La Silla 3.5 m NTT telescopes. Adopting the I -band SBF distance modulus determined by Tonry et al. ([CITE]) and the $\overline M_I$ versus ($V-I$) calibration of Tonry et al. ([CITE]), a value of $\overline M_K =-6.29\pm0.10 $ mag was derived. Relative to the average empirical $\overline M_K$ derived for giant ellipticals by Jensen et al. ([CITE]) ($\overline M_K=-5.61\pm0.12$ mag), the detection of an anomalous K -band SBF in NGC 4489 is confirmed at the two sigma level. Such anomalous fluctuations could be caused by an extended giant branch, consisting of either intermediate-age AGB stars above the tip of the first-ascent giant branch or high-metallicity first-ascent giants, or by lack of a full understanding of the K -band SBF calibration. This result raises questions about the accuracy of K -band SBF distance measurements for elliptical galaxies with unknown stellar composition and underscores the need for $\overline M_K$ measurements over a larger range of color and luminosity.

The Structure of the Virgo Cluster from Surface Brightness Fluctuations inHubble Space TelescopeImages

Surface brightness fluctuations (SBF) in Hubble Space Telescope (HST) Wide Field Planetary Camera 2 images of elliptical galaxies provide the precision necessary to examine the internal structure of the Virgo galaxy cluster. In a sample of 15 elliptical galaxies with observations from the HST archive, we find that most galaxies are within 2 Mpc of NGC 4486, but several galaxies (including NGC 4406) are significantly in the foreground or background. The measured redshifts and distances suggest that all sample galaxies are gravitationally bound to the galaxy cluster. The SBF distances presented here show good agreement with other SBF distance measurements and with distance measurements made using other methods. We include a brief overview of the SBF method, as well as a more detailed description of the SBF calibration used with the data included in this study, which was taken in the HST F814W filter.

Theoretical Predictions for Surface Brightness Fluctuations and Implications for Stellar Populations of Elliptical Galaxies

(Abridged) We present new theoretical predictions for surface brightness fluctuations (SBFs) using models optimized for this purpose. Our predictions agree well with SBF data for globular clusters and elliptical galaxies. We provide refined theoretical calibrations and k-corrections needed to use SBFs as standard candles. We suggest that SBF distance measurements can be improved by using a filter around 1 micron and calibrating I-band SBFs with the integrated V-K galaxy color. We also show that current SBF data provide useful constraints on population synthesis models, and we suggest SBF-based tests for future models. The data favor specific choices of evolutionary tracks and spectra in the models among the several choices allowed by comparisons based on only integrated light. In addition, the tightness of the empirical I-band SBF calibration suggests that model uncertainties in post-main sequence lifetimes are less than +/-50% and that the IMF in ellipticals is not much steeper than that in the solar neighborhood. Finally, we analyze the potential of SBFs for probing unresolved stellar populations. We find that optical/near-IR SBFs are much more sensitive to metallicity than to age. Therefore, SBF magnitudes and colors are a valuable tool to break the age/metallicity degeneracy. Our initial results suggest that the most luminous stellar populations of bright cluster galaxies have roughly solar metallicities and about a factor of three spread in age.

Surface [ITAL]BR[/ITAL] Photometry of Newly Discovered Dwarf Elliptical Galaxies in the Nearby Sculptor and Centaurus A Groups

Prompted by the recent finding of a large number of gas-rich dwarf irregular galaxies in the nearby southern galaxy groups Sculptor (Scl) and Centaurus A (Cen A) we carried out a complementary survey to search for members of the gas-poor dwarf elliptical (dE) galaxy family. In total 18 dE candidates were identified on SRC Sky Survey films covering the group regions. For five dE's in the Scl group and five in the Cen A group, membership information is available from surface brightness fluctuations distance measurements; two dEs in each group also have independent redshift measurements. The remaining eight galaxies have been associated to the groups based on their morphology. We acquired deep B- and R-band CCD images for all galaxies and determined their photometric and structural parameters. According to the magnitude range covered, -14 < MB < -9 (not counting the bright dS0 NGC 59), these objects are local dwarf spheroidal (dSph) analogues. The surface brightness profiles of most dwarfs are strongly nonexponential but are perfectly explained by the three-parametric Sersic law. The best-fitting Sersic parameters are compared with corresponding data for Virgo dE's and dSph's. The present dEs follow the relations between the Sersic parameters and absolute B-band magnitude for Virgo dE's and local dwarfs, thus confirming the membership in the Scl and Cen A groups, respectively. Most of our dwarfs exhibit color gradients in (B-R)0, in the sense of a reddening outward. We also show and discuss the sky distributions and B-band luminosity functions of the Scl and Cen A groups. The completeness magnitude for both populations (from the present survey) is estimated to be M ≈ -13. We find that the composite luminosity function of four nearby galaxy groups is well fitted by a Schechter function down to M = -14 with a faint end slope α = -1.29(±0.10). In the appendices we present best-fitting Sersic profile parameters for the dSph members of the Local Group and introduce two new dwarf irregulars found in the Cen A group.

The Infrared Surface Brightness Fluctuation Distances to the Hydra and Coma Clusters

We present IR surface brightness fluctuation (SBF) distance measurements to NGC 4889 in the Coma cluster and to NGC 3309 and NGC 3311 in the Hydra cluster. We explicitly corrected for the contributions to the fluctuations from globular clusters, background galaxies, and residual background variance. We measured a distance of 85 +/- 10 Mpc to NGC 4889 and a distance of 46 +/- 5 Mpc to the Hydra cluster. Adopting recession velocities of 7186 +/- 428 km/s for Coma and 4054 +/- 296 km/s for Hydra gives a mean Hubble constant of H_0 = 87 +/- 11 km/s/Mpc. Corrections for residual variances were a significant fraction of the SBF signal measured, and, if underestimated, would bias our measurement towards smaller distances and larger values of H_0. Both NICMOS on the Hubble Space Telescope and large-aperture ground-based telescopes with new IR detectors will make accurate SBF distance measurements possible to 100 Mpc and beyond.