HIGH-RESOLUTION MASS MODELS OF DWARF GALAXIES FROM LITTLE THINGS

By Se-Heon Oh, D. Hunter, E. Brinks, Bruce G. Elmegreen, A. Schruba, F. Walter, M. Rupen, L. M. Young, C. Simpson, Megan C. Johnson and 6 more. 2015

343 citations recorded by the source corpus.

We present high-resolution rotation curves and mass models of 26 dwarf galaxies from “Local Irregulars That Trace Luminosity Extremes, The H i Nearby Galaxy Survey” (LITTLE THINGS). LITTLE THINGS is a high-resolution (∼6″ angular; <2.6 km s−1 velocity resolution) Very Large Array H i survey for nearby dwarf galaxies in the local volume within 11 Mpc. The high-resolution H i observations enable us to derive reliable rotation curves of the sample galaxies in a homogeneous and consistent manner. The rotation curves are then combined with Spitzer archival 3.6 μm and ancillary optical U, B, and V images to construct mass models of the galaxies. This high quality multi-wavelength data set significantly reduces observational uncertainties and thus allows us to examine the mass distribution in the galaxies in detail. We decompose the rotation curves in terms of the dynamical contributions by baryons and dark matter (DM) halos, and compare the latter with those of dwarf galaxies from THINGS as well as ΛCDM Smoothed Particle Hydrodynamic (SPH) simulations in which the effect of baryonic feedback processes is included. Being generally consistent with THINGS and simulated dwarf galaxies, most of the LITTLE THINGS sample galaxies show a linear increase of the rotation curve in their inner regions, which gives shallower logarithmic inner slopes α of their DM density profiles. The mean value of the slopes of the 26 LITTLE THINGS dwarf galaxies is &agr; = − 0.32 ± 0.24 ?> which is in accordance with the previous results found for low surface brightness galaxies ( &agr; = − 0.2 ± 0.2 ?> ) as well as the seven THINGS dwarf galaxies ( &agr; = − 0.29 ± 0.07 ?> ). However, this significantly deviates from the cusp-like DM distribution predicted by DM-only ΛCDM simulations. Instead our results are more in line with the shallower slopes found in the ΛCDM SPH simulations of dwarf galaxies in which the effect of baryonic feedback processes is included. In addition, we discuss the central DM distribution of DDO 210 whose stellar mass is relatively low in our sample to examine the scenario of inefficient supernova feedback in low mass dwarf galaxies predicted from recent ΛCDM SPH simulations of dwarf galaxies where central cusps still remain.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/15f4bc789f36546d5a79a33d1e4c20522dd64c69

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

The impact of baryonic physics on the structure of dark matter haloes: the view from the FIRE cosmological simulations (2015, background): “For dwarf galaxies, this is close to the region where observations indicate shallow and core-like profiles in low-mass galaxies (typically measured at a few hundred pc; see Oh et al. 2011, 2015; Walter et al. 2008; Hunter et al. 2012).”
Understanding the shape and diversity of dwarf galaxy rotation curves in ΛCDM (2016, methodology): “DDO 101 is one of the few galaxies in the Little THINGS survey that has a steeply rising rotation curve and this is our motivation for including it here.”
Gravitational probes of dark matter physics (2017, background): “For somewhat larger objects, like the classical dwarf satellites of the Milky Way (with stellar mass M∗ & 10(5)M , many of which were recently star-forming) or the late-type (spiral) dwarf galaxies in the Little Things surveys [250, 251] (Mhalo∼ 10(10)M − 10(11)M ), it is clear that their central de”
Small-Scale Challenges to the ΛCDM Paradigm (2017, background): “The data points show the rotation curves of two example galaxies of this size from the LITTLE THINGS survey (Oh et al. 2015)), which are more slowly rising and better fit by a density profile with a constant density core (Burkert 1995, cyan line). prediction.”
Small scale problems of the $\Lambda$CDM model: a short review (2016, background): “[190,195], LITTLE THINGS [188], THINGS dwarfs [36,164], Sculptor, Fornax and the Milky Way, examining their respective predictions for the slope-stellar mass, and the slope-circular velocity relationships.”
The unexpected diversity of dwarf galaxy rotation curves (2015, methodology): “…5.9 H I 0.2 34.4 43.5 – DDO 87 Oh et al. (2015) 7.7 H I 0.2 28.0 ≥56.6 – DDO 70 Oh et al. (2015) 1.3 H I <0.1 43.9 ≥43.9 – DDO 53 Oh et al. (2015) 3.6 H I 0.1 29.2 ≥32.0 – DDO 52 Oh et al. (2015) 10.3 H I 0.3 42.6 ≥61.7 – DDO 50 Oh et al. (2015) 3.4 H I 0.1 31.2 38.8 – MNRAS 452, 3650–3665…”
Dark matter cores all the way down (2015, methodology): “Both have measured star formation histories (Weisz et al. 2012b; Cole et al. 2014); gas kinematics (Begum & Chengalur 2004; Ryan-Weber et al. 2008; Oh et al. 2015); stellar kinematics (Simon & Geha 2007; Kirby et al. 2014); photometry (Martin et al. 2008; McConnachie et al. 2006); and stellar…”
SPARC: MASS MODELS FOR 175 DISK GALAXIES WITH SPITZER PHOTOMETRY AND ACCURATE ROTATION CURVES (2016, methodology): “We do not consider rotation curves from THINGS (de Blok et al. 2008) and LITTLE-THINGS (Oh et al. 2015) for the sake of homogeneity.”
BREATHING FIRE: HOW STELLAR FEEDBACK DRIVES RADIAL MIGRATION, RAPID SIZE FLUCTUATIONS, AND POPULATION GRADIENTS IN LOW-MASS GALAXIES (2015, background): “…transfer of energy from gas outflows/inflows to collisionless particles is well-studied in the context of the “core-cusp” (Moore 1994; Oh et al. 2015) and related “too-big-to-fail” (Boylan-Kolchin et al. 2011; Jiang & van den Bosch 2015) problems, which express the discrepancy…”
NIHAO – IV: core creation and destruction in dark matter density profiles across cosmic time (2015, methodology): “The red circles with error-bars are the predictions forα f om the NIHAO simulation suite at 1-2% ofRvir, for galaxies with stellar masses between107 − 1010M⊙ to be consistent with the LITTLE THINGS sample range (Oh et al. 2015).”