HIGH-RESOLUTION DARK MATTER DENSITY PROFILES OF THINGS DWARF GALAXIES: CORRECTING FOR NONCIRCULAR MOTIONS

By Se-Heon Oh, W. D. de Blok, F. Walter, E. Brinks, Robert C. Kennicutt Jr.. 2008

249 citations recorded by the source corpus.

We present a new method to remove the impact of random and small-scale noncircular motions from H i velocity fields in (dwarf) galaxies in order to better constrain the dark matter properties for these objects. This method extracts the circularly rotating velocity components from the H i data cube and condenses them into a so-called bulk velocity field. We derive high-resolution (∼0.2 kpc) rotation curves of IC 2574 and NGC 2366 based on bulk velocity fields derived from The H i Nearby Galaxy Survey obtained at the Very Large Array. We compare the bulk velocity field rotation curves with those derived from the traditional intensity-weighted mean velocity fields and find significant differences. The bulk velocity field rotation curves are significantly less affected by noncircular motions and constrain the dark matter distribution in our galaxies, allowing us to address the discrepancy between the inferred and predicted dark matter distribution in galaxies (the “cusp/core” problem). Spitzer Infrared Nearby Galaxies Survey 3.6 μm data, which are largely unaffected by dust in these systems, as well as ancillary optical information, are used to separate the contribution of the baryons from the total matter content. Using stellar population synthesis models, assuming various sets of metallicity and star-formation histories, we compute stellar mass-to-light ratios for the 3.6 μm and 4.5 μm bands. Using our predicted value for the 3.6 μm stellar mass-to-light ratio, we find that the observed dark matter distributions of IC 2574 and NGC 2366 are inconsistent with the cusp-like dark matter halo predicted by Λ Cold Dark Matter models, even after corrections for noncircular motions. This result also holds for other assumptions about the stellar mass-to-light ratio. The distribution of dark matter within our sample galaxies is best described by models with a kpc-sized constant-density core.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/09c44e040f0de0257e8186643068d776281908d6

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Citations in the corpus

3D BAROLO: a new 3D algorithm to derive rotation curves of galaxies (2015, background): “…include intensity-weighted mean along the velocity axis (1st moment, Rogstad & Shostak 1971), fitting single (Begeman 1987; Swaters 1999) or multiple (Oh et al. 2008) Gaussian functions to the profiles, and/or including a skewness term (e.g. h3 Gauss-Hermite polynomial, van der Marel & Franx 1993).”
THINGS: THE H i NEARBY GALAXY SURVEY (2008, methodology): “…kinematics in the individual systems and should be treated with caution when attempting a detailed kinematical analysis. de Blok et al. (2008), Oh et al. (2008) and Trachternach et al. (2008) discuss in detail the various methods that need to be employed for a proper kinematical analysis of…”
THE CENTRAL SLOPE OF DARK MATTER CORES IN DWARF GALAXIES: SIMULATIONS VERSUS THINGS (2010, methodology): “…as beam smearing, center offset and non-circular motions, which may play a role in hiding central cusps (Blais-Ouellette et al. 1999; van den Bosch et al. 2000; Bolatto et al. 2002; Swaters et al. 2003; Simon et al. 2003; Rhee et al. 2004; Gentile et al. 2005; Spekkens et al. 2005; Oh et al. 2008).”
Bar formation and evolution in disc galaxies with gas and a triaxial halo: morphology, bar strength and halo properties (2012, background): “…de Blok et al. 2001, 2008; de Blok & Bosma 2002; de Blok, Bosma & McGaugh 2003; Simon et al. 2003; Kuzio de Naray et al. 2006; Battaglia et al. 2008; Kuzio de Naray, McGaugh & de Blok 2008; Oh et al. 2008; de Blok 2010; Walker & Peñarrubia 2011; Amorisco & Evans 2012; Peñarrubia et al. 2012).”
Determination of the Local Dark Matter Density in our Galaxy (2009, methodology): “where G is the gravitational constant and ρ(r) is the matter density distribution model. For a given DM density profile the gr avitational potential and therefore the rotation curve can be c alculated and a comparison with experimental data is an importan t check for the DM density profile. The rota”
MORPHOLOGICAL QUENCHING OF STAR FORMATION: MAKING EARLY-TYPE GALAXIES RED (2009, background): “…fact that dark matter halos have a flat core is widely observed in the Local Universe (Borriello & Salucci 2001; Salucci 2001; de Block et al. 2003; Oh et al. 2008; Trachternach et al. 2008) and high redshift observations (Förster Schreiber et al. 2006) suggest that the mass in the inner regions…”
DARK AND LUMINOUS MATTER IN THINGS DWARF GALAXIES (2010, methodology): “…at the centers of galaxies (Flores & Primack 1994; Moore 1994; de Blok et al. 2001; de Blok & Bosma 2002; Bolatto et al. 2002; Weldrake et al. 2003; Simon et al. 2003; Swaters et al. 2003; Gentile et al. 2004; Oh et al. 2008; Trachternach et al. 2008; de Blok et al. 2008, and references therein).”
RECONSTRUCTING THE STELLAR MASS DISTRIBUTIONS OF GALAXIES USING S4G IRAC 3.6 AND 4.5 μm IMAGES. I. CORRECTING FOR CONTAMINATION BY POLYCYCLIC AROMATIC HYDROCARBONS, HOT DUST, AND INTERMEDIATE-AGE STARS (2011, unknown): “6 = 3.24 mag, calculated by Oh et al. (2008).”
HALO EXPANSION IN COSMOLOGICAL HYDRO SIMULATIONS: TOWARD A BARYONIC SOLUTION OF THE CUSP/CORE PROBLEM IN MASSIVE SPIRALS (2011, background): “Yet cosmological simulations of more massive disc galaxies have invariably resulted in adiabatic contraction (Gnedin et al. 2011), contradicting observed disc galaxies(Oh et al. 2008, Donato et al. 2009).”
THE BARYONIC TULLY–FISHER RELATION OF GAS-RICH GALAXIES AS A TEST OF ΛCDM AND MOND (2011, background): “In general, these corrections turn out to be rather small (cf. Tully & Fouque 1985; Oh et al. 2008; Trachternach et al. 2009; Dalcanton & Stilp 2010), as the typical velocity dispersion of low mass galaxies is ∼ 8 km s−1 (Kuzio de Naray et al. 2009).”
RECONSTRUCTING THE STELLAR MASS DISTRIBUTIONS OF GALAXIES USING S4G IRAC 3.6 AND 4.5 μm IMAGES. II. THE CONVERSION FROM LIGHT TO MASS (2014, methodology): “We adopt the 3.6 µm and 4.5 µm absolute solar magnitudes calculated by Oh et al. (2008), M3.”
Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies (2012, methodology): “In particular, for the THINGS and LITTLE THINGS samples, we obtain the 3.6µm mass-to-light ratio values from optical colors based on Bruzual & Charlot (2003) stellar population synthesis models (Oh et al. 2008; Bell & de Jong 2001).”
THE SMALL SCATTER OF THE BARYONIC TULLY–FISHER RELATION (2015, background): “Baryonic Masses We estimate the baryonic mass as Mb = Mg + Υ∗L[3.6], (4) where Mg is the gas mass, L[3.6] is the [3.6] luminosity (adopting a solar magnitude of 3.24, Oh et al. 2008), and Υ∗ is the stellar mass-to-light ratio.”
KINEMATICAL AND CHEMICAL VERTICAL STRUCTURE OF THE GALACTIC THICK DISK. II. A LACK OF DARK MATTER IN THE SOLAR NEIGHBORHOOD, (2012, background): “…sets of indices have been proposed in the literature, suggesting either “cuspy” (e.g., Navarro et al. 1997; Moore et al. 1999; Binney & Evans 2001; Ludlow et al. 2009) or “cored” profiles (e.g., de Boer et al. 2005; Narayan et al. 2005; Gentile et al. 2007; Salucci et al. 2007; Oh et al. 2008).”
Surface brightness profile of the Milky Way’s nuclear star cluster (2014, methodology): “The mean total luminosity from the Sérsic and King models is LMWNS C,4.5 µm,S ersic = (4.1 ± 0.3) × 107 L ,4.5 µm and LMWNS C,4.5 µm,King = (4.1 ± 0.3) × 107 L ,4.5 µm, respectively, assuming an absolute magnitude of 3.27 for the Sun in the Spitzer 4.5 µm band (Oh et al. 2008) and a distance modulu”
SPARC: MASS MODELS FOR 175 DISK GALAXIES WITH SPITZER PHOTOMETRY AND ACCURATE ROTATION CURVES (2016, background): “Total luminosities assume a solar absolute magnitude of 3.24 at 3.6 µm (Oh et al. 2008).”
HIGH-RESOLUTION MASS MODELS OF DWARF GALAXIES FROM LITTLE THINGS (2015, methodology): “In order to correct for small-scale random motions and extract only the component due to circular rotating velocity in a galaxy, we derive the ‘bulk velocity field’ as proposed by Oh et al. (2008; 2011b).”