THE H I CHRONICLES OF LITTLE THINGS BCDs II: THE ORIGIN OF IC 10's H I STRUCTURE

Ashley, Trisha; Elmegreen, Bruce G.; Johnson, Megan; Nidever, David L.; Simpson, Caroline E.; Pokhrel, Nau Raj

doi:10.1088/0004-6256/148/6/130

Cited by 38 publications

(46 citation statements)

References 49 publications

(69 reference statements)

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“…1 shows a distribution of gas and stars that shares characteristics with the irregular dwarf galaxy IC10: a disturbed gas and stellar distribution with multiple starforming cores and an extended HI distribution with plums and spurs with velocities that differ from that of the main gas disk (see for example Ashley et al 2014). On the other hand, the HII regions have a low metallicity (Garnett 1990) which has been suggested as being due to the influx of fresh pristine gas from the environment (Sánchez Almeida et al 2014).…”

Section: Some Intriguing Casesmentioning

confidence: 95%

Dark influences

Starkenburg

Helmi

Sales

2016

A&A

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Context. In the current concordance cosmology small halos are expected to be completely dark and can significantly perturb lowmass galaxies during minor merger interactions. These interactions may well contribute to the diversity of the dwarf galaxy population. Dwarf galaxies in the field are often observed to have peculiarities in their structure, morphology, and kinematics, as well as strong bursts of star formation without apparent cause. Aims. We aim to characterise the signatures of minor mergers of dwarf galaxies with dark satellites to aid their observational identification. Methods. We explored and quantified a variety of structural, morphological, and kinematic indicators of merging dwarf galaxies and their remnants using a suite of hydrodynamical simulations. Results. The most sensitive indicators of mergers with dark satellites are large asymmetries in the gaseous and stellar distributions, enhanced central surface brightness and starbursts, and velocity offsets and misalignments between the gas and stellar components. In general, merging systems span a wide range of values of the most commonly used indicators, while isolated objects tend to have more confined values. Interestingly, we find in our simulations that a significantly off-centred burst of star formation can pinpoint the location of the dark satellite. Observational systems with such characteristics are perhaps the most promising for unveiling the presence of the hitherto missing satellites.

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Section: Some Intriguing Casesmentioning

confidence: 95%

Dark influences

Starkenburg

Helmi

Sales

2016

A&A

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“…The approximately constant trend of f gas as a function of galaxy morphology for T > 6 galaxies might be due to the fact that our analysis refers to the optical disk, while later-type galaxies (e.g., the irregulars) are typically Hi-dominated and this gas is mainly located in the outer parts, beyond r 25 (e.g. IC 10, Ashley et al 2014).…”

Section: Gas Fractionmentioning

confidence: 99%

The ISM scaling relations in DustPedia late-type galaxies: A benchmark study for the Local Universe

Casasola

Bianchi

Vis

et al. 2020

A&A

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Aims. The purpose of this work is the characterization of the main scaling relations between all of the interstellar medium (ISM) components, namely dust, atomic, molecular, and total gas, and gas-phase metallicity, as well as other galaxy properties, such as stellar mass (M star ) and galaxy morphology, for late-type galaxies in the Local Universe. Methods. This study was performed by extracting late-type galaxies from the entire DustPedia sample and by exploiting the large and homogeneous dataset available thanks to the DustPedia project. The sample consists of 436 galaxies with morphological stage spanning from T = 1 to 10, M star from 6 × 10 7 to 3 × 10 11 M , star formation rate from 6 × 10 −4 to 60 M yr −1 , and oxygen abundance from 12 + log(O/H) = 8 to 9.5. Molecular and atomic gas data were collected from the literature and properly homogenized. All the masses involved in our analysis refer to the values within the optical disks of galaxies. The scaling relations involving the molecular gas are studied by assuming both a constant and a metallicity-dependent CO-to-H 2 conversion factor (X CO ). The analysis was performed by means of the survival analysis technique, in order to properly take into account the presence of both detection and nondetection in the data. Results. We confirm that the dust mass correlates very well with the total gas mass, and find -for the first time-that the dust mass correlates better with the atomic gas mass than with the molecular one. We characterize important mass ratios such as the gas fraction, the molecular-to-atomic gas mass ratio, the dust-to-total gas mass ratio (DGR), and the dust-to-stellar mass ratio, and study how they relate to each other, to galaxy morphology, and to gas-phase metallicity. Only the assumption of a metallicity-dependent X CO reproduces the expected decrease of the DGR with increasing morphological stage and decreasing gas-phase metallicity, with a slope of about 1. The DGR, the gas-phase metallicity, and the dust-to-stellar mass ratio are, for our galaxy sample, directly linked to galaxy morphology. The molecular-to-atomic gas mass ratio and the DGR show a positive correlation for low molecular gas fractions, but for galaxies rich in molecular gas this trend breaks down. To our knowledge, this trend has never been found before, and provides new constraints for theoretical models of galaxy evolution and a reference for high-redshift studies. We discuss several scenarios related to this finding. Conclusions. The DustPedia database of late-type galaxies is an extraordinary tool for the study of the ISM scaling relations, thanks to its homogeneous collection of data for the different ISM components. The database is made publicly available to the whole community.

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“…They explained that the features seen in IC 10 correspond to what would be seen for a galaxy experiencing later stages of formation via the ongoing infall of primordial material. Recent Hi studies of IC 10 suggest that an interaction or merger with another unknown low surface density dwarf galaxy is the most probable explanation for the observed morphology of this galaxy (Nidever et al 2013;Ashley et al 2014). However, Gerbrandt et al (2015) argued that the lack of streams or shells, or any disturbances in the stellar component of IC 10 strongly indicates that it is unlikely that IC 10 has undergone an interaction with an unknown companion.…”

Section: Introductionmentioning

confidence: 99%

H i observations of IC 10 with the DRAO synthesis telescope

Namumba

Carignan

Foster

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Hi observations of the nearby blue compact dwarf galaxy IC 10 obtained with the Dominion Radio Astrophysical Observatory synthesis telescope (DRAO), for a total integration of ∼1000 hours, are presented. We confirm the NW faint 21 cm Hi emission feature discovered in GBT observations. The Hi feature has an Hi mass of 4.7 ×10 5 M , which is only ∼ 0.6% of the total Hi mass of the galaxy (7.8 ×10 7 M ). In the inner disk, the rotation curve of IC 10 rises steeply, then flattens until the last point where it rises again, with a maximum velocity of 30 km s −1 . Based on our mass models, the kinematics of the inner disk of IC 10 can be described without the need of a dark matter halo. However, this does not exclude the possible presence of dark matter on a larger scale. It is unlikely that the disturbed features seen in the outer Hi disk of IC 10 are caused by an interaction with M 31. Features seen from our simulations are larger and at lower surface density than can be reached by current observations. The higher velocity dispersions seen in regions where several distinct Hi features meet with the main core of IC 10 suggests that there is ongoing accretion.

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THE H I CHRONICLES OF LITTLE THINGS BCDs II: THE ORIGIN OF IC 10's H I STRUCTURE

Cited by 38 publications

References 49 publications

Dark influences

Dark influences

The ISM scaling relations in DustPedia late-type galaxies: A benchmark study for the Local Universe

H i observations of IC 10 with the DRAO synthesis telescope

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