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NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (And Beyond

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NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (And Beyond Publication Year 2018 Acceptance in OA@INAF 2020-11-02T17:16:45Z Title The Next Generation Virgo Cluster Survey (NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (and Beyond) Authors CANTIELLO, Michele; Blakeslee, John P.; Ferrarese, Laura; Côté, Patrick; Roediger, Joel C.; et al. DOI 10.3847/1538-4357/aab043 Handle http://hdl.handle.net/20.500.12386/28125 Journal THE ASTROPHYSICAL JOURNAL Number 856 The Astrophysical Journal, 856:126 (18pp), 2018 April 1 https://doi.org/10.3847/1538-4357/aab043 © 2018. The American Astronomical Society. All rights reserved. The Next Generation Virgo Cluster Survey (NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (and Beyond) Michele Cantiello1 , John P. Blakeslee2 , Laura Ferrarese2,3 , Patrick Côté2, Joel C. Roediger2 , Gabriella Raimondo1, Eric W. Peng4,5 , Stephen Gwyn2, Patrick R. Durrell6 , and Jean-Charles Cuillandre7 1 INAF Osservatorio Astronomico d’Abruzzo, via Maggini, snc, I-64100, Italy; [email protected] 2 National Research Council of Canada, Herzberg Astronomy and Astrophysics Research Centre, Victoria, BC, Canada 3 Gemini Observatory, Northern Operations Center, 670 N.A’ohoku Place, Hilo, HI 96720, USA 4 Department of Astronomy, Peking University, Beijing 100871, People’s Republic of China 5 Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, People’s Republic of China 6 Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555, USA 7 AIM Paris Saclay, CNRS/INSU, CEA/Irfu, Université Paris Diderot, Orme des Merisiers, France Received 2017 October 26; revised 2018 February 14; accepted 2018 February 14; published 2018 March 30 Abstract We describe a program to measure surface brightness fluctuation (SBF) distances to galaxies observed in the Next Generation Virgo Cluster Survey (NGVS), a photometric imaging survey covering 104 deg2 of the Virgo cluster in the u*, g, i, and z bandpasses with the Canada–France–Hawaii Telescope. We describe the selection of the sample galaxies, the procedures for measuring the apparent i-band SBF magnitude mi, and the calibration of the absolute Mi as a function of observed stellar population properties. The multiband NGVS data set provides multiple options for calibrating the SBF distances, and we explore various calibrations involving individual color indices as well as combinations of two different colors. Within the color range of the present sample, the two-color calibrations do not significantly improve the scatter with respect to wide-baseline, single-color calibrations * involving u . We adopt the ()uz* - calibration as a reference for the present galaxy sample, with an observed scatter of 0.11mag. For a few cases that lack good u* photometry, we use an alternative relation based on a combination of (gi- ) and (gz- ) colors, with only a slightly larger observed scatter of 0.12mag. The agreement of our measurements with the best existing distance estimates provides confidence that our measurements are accurate. We present a preliminary catalog of distances for 89 galaxies brighter than BT≈13.0 mag within the survey footprint, including members of the background M and W Clouds at roughly twice the distance of the main body of the Virgo cluster. The extension of the present work to fainter and bluer galaxies is in progress. Key words: distance scale – galaxies: clusters: individual (Virgo) – galaxies: distances and redshifts 1. Introduction been used to calibrate the latter three methods, which have ranges extending out into the Hubble flow. Reliable distance estimation is an essential prerequisite for Most of the precision methods reviewed by Freedman & knowledge of the fundamental characteristics of structures in Madore (2010) have been applied to measure distances of the universe, including their size, luminosity, and mass. fi galaxies in the Virgo cluster, thanks to its proximity, with the Measurement of signi cant samples of high-quality galaxy exception being the water masers, which are very rare. However, distances can enable mapping of large-scale structures and fi not all of the methods are practical for mapping the 3D structure velocity elds in the nearby universe, where the peculiar of the cluster. For instance, Cepheids bolster the rung of the velocity is often a substantial fraction of the redshift. Resolving ladder by which our knowledge of distances ascends from the the 3D structure of galaxies within clusters requires measure- solar neighborhood to the realm of the galaxies. However, at ment precision for individual galaxies better than the ratio of extragalactic distances, Cepheids require many epochs of deep, < the cluster depth to its mean distance, or errors 0.1 mag even high-resolution observations and are only found within star- ≈ for Virgo and Fornax, the only galaxy clusters within 20 Mpc forming galaxies, not in the early-type galaxies that populate (Mei et al. 2007; Blakeslee et al. 2009, hereafter B09). dense environments. The TF relation has traditionally produced There are very few extragalactic distance indicators that are distance errors 0.3mag, much larger than the depth of the both capable of this level of precision, and able to be applied to Virgo cluster, but as Freedman & Madore (2010) discuss, the a large fraction of galaxies within a given environment. For precision is vastly improved when using 3.6 μmphotometry. instance, the extensive review by Freedman & Madore However, again the method works best for spiral galaxies, rather (2010) discusses “six high-precision (extragalactic) distance- than cluster ellipticals. On the other hand, TypeIa supernovae determination methods,” namely, Cepheid variables, the tip of (SNe Ia) occur in all galaxy types and are highly luminous, the red giant branch (TRGB), water masers, the Tully–Fisher making them easily observable in the nearby universe. However, (TF) relation, TypeIa supernovae (SNe Ia), and surface they are rare events; according to the NASA/IPAC Extragalactic brightness fluctuations (SBFs). The first three of these methods Database (NED),8 the last SNe Ia to occur in the Virgo cluster require high spatial resolution and have mainly been used for cD galaxy M87 was a century ago, SN 1919A, and no confirmed nearby galaxies, i.e., at distances 20Mpc where peculiar velocities are comparable to the Hubble velocity; they have 8 http://ned.ipac.caltech.edu 1 The Astrophysical Journal, 856:126 (18pp), 2018 April 1 Cantiello et al. SNe Ia have occurred in the brightest cluster galaxy M49, complete areal coverage, one must resort to wide-field imaging despite its enormous stellar mass. The TRGB method is also from the ground. The only previous major ground-based SBF applicable to all types of galaxies, but very deep high-resolution survey was by Tonry et al. (1997, 2001), which reported distances imaging is required to reach a sufficient depth along the RGB in of variable precision, acquired in the I band under conditions of external galaxies; consequently, very few galaxies in the Virgo highly variable quality, for ≈300 galaxies out to about 40Mpc, cluster have TRGB distance estimates (Durrell et al. 2007; Bird including 31 in the Virgo cluster. There have been major advances et al. 2010;Lee&Jang2017). in both CCD cameras and in the efficiency of observatory Other methods with the potential for mapping the Virgo operations since the observations were conducted for that seminal cluster region include Mira variables (e.g., Whitelock survey more than 20years ago; these advances greatly increase et al. 2008) and the globular cluster luminosity function (GCLF; the potential of the SBF method and make it well worth revisiting e.g., Harris 1991). Miras are luminous asymptotic giant branch today. In fact, Tonry et al. (2001) hypothesized a future survey stars, especially bright in the infrared, and likely present in most that would repeat the SBF measurements for all the same galaxies galaxies. However, like the other resolved stellar photometry in only one-fourth of the integration time and yield distances with methods, Miras require very high spatial resolution and much 40% better precision because it would be conducted with a longer temporal baselines then Cepheids. Thus far, this method median seeing of 0 6, instead of ≈0 9. has only been used to distances of a few megaparsec The Next Generation Virgo Cluster Survey (NGVS; Ferrarese 2 (Rejkuba 2004), but it may become much more far-reaching et al. 2012) is a Large Program with the 1-deg MegaCam with the combination of Gaia and the James Webb Space imager at the MegaPrime focus of the Canada–France–Hawaii Telescope (JWST). Gaia is expected to measure parallaxes for Telescope (CFHT). In 117 pointings (not including background 2 ∼40,000 Miras (Robin et al. 2012),andJWST will operate in the fields), it covers a contiguous 104deg of the Virgo cluster, out to the virial radii for both the VirgoA and B subclusters, in the near- and mid-IR regime, where Miras reach magnitudes brighter * than ≈−8mag(Feast & Whitelock 2014, ≈−9.2 mag at 8 μm). u , g, i,andz bandpasses. It supersedes all previous optical GCLF measurements have been made for large samples of studies of Virgo and leverages a large amount of spectroscopic galaxies in the Virgo and Fornax clusters (Jordán et al. 2006; followup and auxiliary data at other wavelengths to address Villegas et al. 2010), but in addition to the established trends important questions about the galaxy luminosity function, with host galaxy luminosity, the distance indicator likely scaling relations, stellar populations, dynamical interactions, depends in complex ways on galaxy environment and dynamical GCs, galactic nuclei, and the growth of the cluster itself. The history (e.g., Rejkuba 2012). Overall, it appears to be a less NGVS project motivations, strategy, and observational program ( ) precise method than the others mentioned above, especially for are discussed in detail by Ferrarese et al. 2012 .
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