EIG - II. Intriguing characteristics of the most extremely isolated galaxies

Abstract

We have selected a sample of 41 extremely isolated galaxies (EIGs) from the local universe using both optical and HI ALFALFA redshifts (Spector & Brosch 2016). Narrow band H${}_{\alpha }$ and wide band imaging along with public data were used to derive star formation rates (SFRs), star formation histories (SFHs), and morphological classifications for the EIGs. We have found that the extreme isolation of the EIGs does not affect considerably their star-formation compared to field galaxies. EIGs are typically `blue cloud' galaxies that fit the `main sequence of star forming galaxies' and may show asymmetric star formation and strong compact star-forming regions. We discovered surprising environmental dependencies of the HI content, M${}_{HI}$, and of the morphological type of EIGs; The most isolated galaxies (of subsample EIG-1) have lower M${}_{HI}$ on average (with $2.5\sigma$ confidence) and a higher tendency to be early-types (with 0.94 confidence) compared to the less isolated galaxies of subsample EIG-2. To the best of our knowledge this is the first study that finds an effect in which an isolated sample shows a higher fraction of early-types compared to a less isolated sample. Both early-type and late-type EIGs follow the same colour-to-M${}_{\ast }$, SFR-to-M${}_{\ast }$ (`main sequence') and M${}_{HI}$-to-$M_{\ast }$ relations. This indicates that the mechanisms and factors governing star formation, colour and the M${}_{HI}$-to-M${}_{\ast }$ relation are similar in early-type and late-type EIGs, and that the morphological type of EIGs is not governed by their M${}_{HI}$ content, colour or SFR.

arXiv comment40 pages; 17 figures; 12 tables

References in corpus (78)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Star Formation in Galaxies Along the Hubble Sequence
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Cosmological parameters from CMB and other data: a Monte-Carlo approach
• Star Formation in the Milky Way and Nearby Galaxies
• The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission
• The Average Star Formation Histories of Galaxies in Dark Matter Halos from z=0-8
• Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
• K-corrections and filter transformations in the ultraviolet, optical, and near infrared
• UV Star Formation Rates in the Local Universe
• Color Separation of Galaxy Types in the Sloan Digital Sky Survey Imaging Data
• The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment
• Galaxy bimodality versus stellar mass and environment
• Gas-regulation of galaxies: the evolution of the cosmic sSFR, the metallicity-mass-SFR relation and the stellar content of haloes
• Calibrating Extinction-Free Star Formation Rate Diagnostics with 33GHz Free-Free Emission in NGC6946
• The Arecibo Legacy Fast ALFA Survey: I. Science Goals, Survey Design and Strategy
• Spectral Irradiance Calibration in the Infrared. XIV: the Absolute Calibration of 2MASS
• The Green Valley is a Red Herring: Galaxy Zoo reveals two evolutionary pathways towards quenching of star formation in early- and late-type galaxies
• The Arecibo Legacy Fast ALFA Survey: The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function
• The SDSS View of the Palomar-Green Bright Quasar Survey
• Dust-Corrected Star Formation Rates of Galaxies. II. Combinations of Ultraviolet and Infrared Tracers
• Determining Star Formation Rates for Infrared Galaxies
• Galaxy Zoo: the dependence of morphology and colour on environment
• The Impact of cold gas accretion above a mass floor on galaxy scaling relations
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies?
• The HST Key Project on the Extragalactic Distance Scale. XXVIII. Combining the Constraints on the Hubble Constant
• Connecting Galaxies, Halos, and Star Formation Rates Across Cosmic Time
• New Models for Wolf-Rayet and O Star Populations in Young Starbursts
• Empirical extinction coefficients for the GALEX, SDSS, 2MASS and WISE passbands
• Galaxy formation in WMAP1 and WMAP7 cosmologies
• Galaxy Masses
• The Arecibo Legacy Fast ALFA Survey: The Galaxy Population Detected by ALFALFA
• The impact of nebular emission on the ages of z~6 galaxies
• Connecting the cosmic web to the spin of dark halos: implications for galaxy formation
• Spin alignment of dark matter haloes in filaments and walls
• The effect of the environment on the HI scaling relations
• Photometric Properties of Void Galaxies in the Sloan Digital Sky Survey
• Galaxy Zoo: A sample of blue early-type galaxies at low redshift
• The spin and orientation of dark matter halos within cosmic filaments
• Observational $5-20\mu$m Interstellar Extinction Curves Toward Star-Forming Regions Derived from Spitzer IRS Spectra
• The Arecibo Legacy Fast ALFA Survey: III. HI Source Catalog of the Northern Virgo Cluster Region
• Spectroscopic Properties of Void Galaxies in the Sloan Digital Sky Survey
• The Void Galaxy Survey: Optical Properties and H I Morphology and Kinematics
• How Do Star-Forming Galaxies at Z>3 Assemble Their Masses?
• The origin of scatter in the stellar mass - halo mass relation of central galaxies in the EAGLE simulation
• Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe
• Satellite abundances around bright isolated galaxies
• The Arecibo Legacy Fast ALFA Survey: IV. Strategies for Signal Identification and Survey Catalog Reliability
• The AMIGA sample of isolated galaxies. V. Quantification of the isolation
• The stellar-to-halo mass relations of local galaxies segregates by color
• The universal nature of subhalo accretion
• An Imaging and Spectroscopic Survey of Galaxies Within Prominent Nearby Voids. I. The Sample and Luminosity Distribution
• The Void Phenomenon Explained
• SED fitting with Markov Chain Monte Carlo: Methodology and Application to z=3.1 Lyman Alpha Emitting Galaxies
• An Investigation of Sloan Digital Sky Survey Imaging Data and Multi-Band Scaling Relations of Spiral Galaxies (with Dynamical Information)
• The stellar mass-size relation for the most isolated galaxies in the local Universe
• Properties of Isolated Disk Galaxies
• The AMIGA sample of isolated galaxies - II. Morphological refinement
• The UNAM-KIAS Catalog of Isolated Galaxies
• The Void Galaxy Survey: Star Formation Properties
• Where do "red and dead" early-type void galaxies come from?
• The HI Mass Function and Velocity Width Function of Void Galaxies in the Arecibo Legacy Fast ALFA Survey
• On the Star Formation Properties of Void Galaxies
• Catalog of Isolated Galaxies Selected from the 2MASS Survey
• Studies of galaxies in voids. I. HI observations of Blue Compact Galaxies
• The AMIGA sample of isolated galaxies XI. A First Look at Isolated Galaxy Colors
• Isolated elliptical galaxies in the local Universe
• Central galaxies in different environments: Do they have similar properties?
• Continuum removal in Hα extragalactic measurements
• Catalog of Nearby Isolated Galaxies in the Volume z<0.01
• Are (pseudo)bulges in isolated galaxies actually primordial relics?
• The stellar mass - halo mass relation from galaxy clustering in VUDS: a high star formation efficiency at z~3
• The NGC 672 and NGC 784 Galaxy Groups: Evidence for Galaxy Formation and Growth Along a Nearby Dark Matter Filament
• Star Formation in Dwarf Galaxies
• Star Formation in Nearby Isolated Galaxies
• Colours of isolated galaxies selected from the Two-Micron All-Sky Survey
• Extremely Isolated Galaxies I. Sample and Simulation Analysis

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