bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolated dwarf galaxies in the Local Group
Authors: Higgs Clare R. , McConnachie Alan W. ,   the  Collaboration
Published: October 2019

AbstractThe Solo (Solitary local) Dwarf Galaxy Survey is a volume limited sample of all nearby (< 3 Mpc) and isolated (> 300 kpc from the Milky Way or M31) dwarfs, with wide-field g and i imaging. This survey uses resolved stellar populations to parameterize these low mass systems. Comparison to the well studied satellite dwarfs characterizes the evolutionary impact of a large galaxy in close proximity. The deep, wide field nature of this survey also lends itself to searching for nearby substructures, both globular clusters and possible faint satellites.Current work is focused on the 16 closest Solo dwarfs, all within the virial radius (approximately 1 Mpc) of the Local Group. This subset has been characterized using consistent methods, despite their diversity in stellar mass and apparent size. The analysis highlights the extended stellar structure and morphology. We will examine trends with star formation history, and separation from a large host. This first subset emphasizes the survey’s unique challenges and advantages.The Solo Survey provides detailed look at the extended structure of dwarfs and characterizes the evolution of galaxies in the faint limit.
Hot star wind mass-loss rate predictions at low metallicity
Authors: Krtička Jiří , Kubát Jiří 
Published: October 2019

AbstractHot star winds are driven by the radiative force due to light absorption in lines of heavier elements. Therefore, the amount of mass lost by the star per unit of time, i.e., the mass-loss rate, is sensitive to metallicity. We provide mass-loss rate predictions for O stars with mass fraction of heavier elements 0.2 <Z/Z⊙ ≤ 1. Our predictions are based on global model atmospheres. The models allow us to predict wind terminal velocity and the mass-loss rate just from basic global stellar parameters. We provide a formula that fits the mass-loss rate predicted by our models as a function of stellar luminosity and metallicity. On average, the mass-loss rate scales with metallicity as (Z/Z⊙)0.59. The predicted mass-loss rates agree with mass-loss rates derived from ultraviolet wind line profiles. At low metallicity, the rotational mixing affects the wind mass-loss rates. We study the influence of magnetic line blanketing.
Galactic Ambient of Host Galaxies of GRBs
Authors: Bernal Santiago , Vásquez Nicolás , Hoyle Fiona , Calderón Jaime 
Published: October 2019

AbstractWe studied a sample of 1672 galaxies in regions where a GRB event had occurred, in order to determine if the galactic environment plays a significant role on these energetic events. The Luminosity Function distribution for these galaxies shows some interesting features. For instance, there is a decline on the Luminosity Function at Mr~ −20.5; a lack of flatness at Mr~ −14 and higher-than-expected values of Φ(Mr) for Mr < −22.5. A comparison between our data and the Void, Wall and Early galaxies Luminosity Function was performed.
The Local Group Dwarf Galaxies. The Star Formation Histories derived using the Long Period Variable Stars
Authors: Saremi Elham , Javadi Atefeh , van Loon Jacco Th. , Khosroshahi Habib , Rezaei kh Sara , Golshan Roya Hamedani , Hashemi Seyed A. 
Published: October 2019

AbstractDwarf galaxies in the Local Group (LG) represent a distinct as well as diverse family of tracers of the earliest phases of galaxy assembly and the processing resulting from galactic harrassment. Their stellar populations can be resolved and used as probes of the evolution of their host galaxy. In this regard, we present the first reconstruction of the star formation history (SFH) of them using the most evolved AGB stars that are long period variable (LPV). LPV stars trace stellar populations as young as ∼ 30 Myr to as old as the oldest globular clusters. For the nearby, relatively massive and interacting gas-rich dwarf galaxies, the Magellanic Clouds, we found that the bulk of the stars formed ∼ 10 Gyr ago for the LMC, while the strongest episode of star formation in the SMC occurred a few Gyr later. A peak in star formation around 0.7 Gyr ago in both Clouds is likely linked to their recent interaction. The Andromeda satellite pair NGC147/185 show different histories; the main epoch of star formation for NGC 185 occurred 8.3 Gyr ago, followed by a much lower, but relatively constant star formation rate (SFR). In the case of NGC 147, the SFR peaked only 6.9 Gyr ago, staying intense until ∼ 3 Gyr ago. Star formation in the isolated gas-rich dwarf galaxy IC 1613 has proceeded at a steady rate over the past 5 Gyr, without any particular dominant epoch. Due to lack of sufficient data, we have conducted an optical monitoring survey at the Isaac Newton Telescope (INT) of 55 dwarf galaxies in the LG to reconstruct the SFH of them uniformly. The observations are made over ten epochs, spaced approximately three months apart, as the luminosity of LPV stars varies on timescales of months to years. The system of galactic satellites of the large Andromeda spiral galaxy (M31) forms one of the key targets of our monitoring survey. We present the first results in the And I dwarf galaxy, where we discovered 116 LPVs among over 10,000 stars.
The Hi Neighborhoods Around STARBIRDS
Authors: Johnson Megan C. , McQuinn Kristen B. W. , Cannon John , Martinkus Charlotte , Skillman Evan , Bailin Jeremy , Ford H. Alyson , Hunt Lucas , Westmeier Tobias , Wong O. Ivy , Kamphuis Peter 
Published: October 2019

AbstractStarbursts are finite periods of intense star formation (SF) that can dramatically impact the evolutionary state of a galaxy. Recent results suggest that starbursts in dwarf galaxies last longer and are distributed over more of the galaxy than previously thought, with star formation efficiencies (SFEs) comparable to spiral galaxies, much higher than those typical of non-bursting dwarfs. This difference might be explainable if the starburst mode is externally triggered by gravitational interactions with other nearby systems. We present new, sensitive neutral hydrogen observations of 18 starburst dwarf galaxies, which are part of the STARburst IRregular Dwarf Survey (STARBIRDS) and each were mapped with the Green Bank Telescope (GBT) and/or Parkes Telescope in order to study the low surface brightness gas distributions, a common tracer for tidal interactions.
HI gas component in dwarf and disk galaxies in the view of semi-analytic models
Authors: Fu Jian 
Published: October 2019

AbstractWe show our recent progress on the L-Galaxies semi-analytic models of galaxy formation, which focuses on the HI gas in low mass galaxies. We find that the model based on ELUCID haloes can reproduce the HI mass function from ALFALFA 100 at low mass end. On the other hand, our models predict some gas rich low mass galaxies around the Milky Way, which may offer opportunities for future HI 21cm survey in nearby universe by FAST and SKA-1.
Dwarf Galaxies in the Local Volume
Authors: Karachentsev Igor D. , Kaisina E. I. 
Published: October 2019

AbstractThe Updated Nearby Galaxy Catalog (=UNGC) of 1047 Local Volume (=LV) galaxies, situated within a distance of 11 Mpc, contains 870 dwarfs, i.e. 5/6 of the sample. Almost 40% of them have accurate distances measured with Hubble Space Telescope. Most of the LV dwarfs have been observed in HI and Hα emission lines, as well in far-ultraviolet with GALEX. We present basic properties of the LV dwarfs, their HI -mass content and star-formation rate in different local environments. We discuss a baryonic Tully-Fisher relation for the LV dwarfs, and apply it to determine TF -distances for several hundreds local galaxies. The accurate distances and radial velocities of the LV dwarfs are used by us to trace dark matter distribution within 11 Mpc. We discuss also does the Local Group may be treated as a typical or uncommon representative of the LV population.
The evolution of the luminosity function faint end of cluster galaxies in the Cluster-EAGLE simulation
Authors: Negri Andrea , Vecchia Claudio Dalla , Aguerri Alfonso , Bahé Yannick , Barnes David , Kay Scott 
Published: October 2019

AbstractIn the last decade observations have been able to probe the evolution of the galaxy luminosity function, in particular showing a variation of its faint-end with redshift. We employ the data of the Cluster-EAGLE project, a set of cosmological, hydrodynamical zoom-in simulations of 30 galaxy clusters, to study the evolution of the galaxy luminostity functions in clusters with redshift. We compile a catalogue of simulated galaxies’ luminosities in the SDSS bands using the E-MILES spectra database, and taking into account dust attenuation. Stacked luminosity functions present little evolution with redshift of the faint-end slope from z=3.5 to z=0, regardless of the cluster mass.
Bright-red stars in the dwarf irregular galaxy Leo A
Authors: Leščinskaitė Alina , Stonkutė Rima , Vansevičius Vladas 
Published: October 2019

AbstractWe analysed a population of bright-red (BR) stars in the dwarf irregular galaxy Leo A by using multicolour photometry data obtained with the Subaru/Suprime-Cam (B, V, R, I,Hα) and HST/ACS (F475W & F814W) instruments. In order to separate the Milky Way (MW) and Leo A populations of red stars, we developed a photometric method, which enabled us to study the spatial distribution of BR stars within the Leo A galaxy.We found a significant difference in the scale-length (S-L) of radial distributions of the “young” and “old” red giant branch (RGB) stars – 0′.82 ± 0′.04 and 1′53 ± 0′.03, respectively. Also, we determined the S-L of BR stars of 0′.85 ± 0′.05, which closely matches that of the “young” RGB stars. Additionally, we found a sequence of peculiar RGB stars and 8 dust-enshrouded stars in the Leo A galaxy.
The Milky Way’s total satellite population and constraining the mass of the warm dark matter particle
Authors: Newton Oliver , Cautun Marius , Jenkins Adrian , Frenk Carlos S. , Helly John C. 
Published: October 2019

AbstractThe Milky Way’s (MW) satellite population is a powerful probe of warm dark matter (WDM) models as the abundance of small substructures is very sensitive to the properties of the WDM particle. However, only a partial census of the MW’s complement of satellite galaxies exists because surveys of the MW’s close environs are incomplete both in depth and in sky coverage. We present a new Bayesian analysis that combines the sample of satellites recently discovered by the Dark Energy Survey (DES) with those found in the Sloan Digital Sky Survey (SDSS) to estimate the total satellite galaxy luminosity function down to Mv = 0. We find that there should be at least $124_{ - 27}^{ + 40}$ (68% CL, statistical error) satellites as bright or brighter than Mv = 0 within 300 kpc of the Sun, with only a weak dependence on MW halo mass. When it comes online the Large Synoptic Survey Telescope should detect approximately half of this population. We also show that WDM models infer the same number of satellites as in ΛCDM, which will allow us to rule out those models that produce insufficient substructure to be viable.
Detection of AGB stars in the IC 10 dwarf irregular galaxy
Authors: Gholami Mahtab , Javadi Atefeh , van Loon Jacco Th. , Khosroshahi Habib , Mirtorabi Mohammad Taghi , Saremi Elham , Eftekhari Samaneh 
Published: October 2019

AbstractAmongst the dwarf galaxies in the Local Group, the isolated irregular one, IC 10 is one of the most interesting galaxies, with strong star forming activity and the highest density of Wolf-Rayet stars. Undergoing a starburst phase, having numerous HII regions and being bright in all wavebands, makes it an exquisite galaxy to study the internal and external processes that continue to affect dwarf galaxies 14 Gyr since the Big Bang. In this study, we present a new deep and precise optical monitoring survey of IC 10 using the Isaac Newton Telescope (INT) with the wide field camera (WFC). We performed observations at nine epochs spaced between three to four months apart between 2015 and 2017. We identified Long Period Variable stars (LPVs), Asymptotic Giant Branch stars (AGBs) and Red Super Giant stars (RSGs) to determine the star formation history and chemical evolution of IC 10.
The properties of bright globular clusters, ultra-compact dwarfs and dwarf nuclei in the Virgo core: hints on origin of ultra-compact dwarf galaxies (UCDs)
Authors: Liu Chengze , Peng Eric W. , Côté Patrick , Zhang Hong-Xin , Ferrarese Laura , Jordán Andrés , Mihos J. Christopher , Muñoz Roberto P. , Puzia Thomas H. , Lançon Ariane , Gwyn Stephen , Cuillandre Jean-Charles , Blakeslee John P. , Boselli Alessandro , Durrell Patrick R. , Duc Pierre-Alain , Guhathakurta Puragra , MacArthur Lauren A. , Mei Simona , Sánchez-Janssen Rubén , Xu Haiguang 
Published: October 2019

AbstractBased on the data from the Next Generation Virgo cluster Survey (NGVS), we statistically study the photometric properties of globular clusters (GCs), ultra-compact dwarfs (UCDs) and dwarf nuclei in the Virgo core (M87) region. We found an obvious negative color (g - z) gradient in GC system associate with M87, i.e. GCs in the outer regions are bluer. However, such color gradient does not exist in UCD system, neither in dwarf nuclei system around M87. In addition, we found that many UCDs are surrounded by extended, low surface brightness envelopes. The dwarf nuclei and UCDs show different spatial distributions from GCs, with dwarf nuclei and UCDs (especially for the UCDs with visible envelopes) lying at larger distances to the Virgo center. These results support the view that UCDs (at least for a fraction of UCDs) are more tied to dwarf nuclei than to GCs.
Nearby void dwarf galaxies: recent results, the ongoing project and prospects
Authors: Pustilnik Simon A. , Makarov Dmitri I. , Tepliakova Arina L. 
Published: October 2019

AbstractProperties of dwarf galaxies formed and evolved in the lowest density environment remain largely unexplored and poorly understood. Especially this concerns the low-mass end (Mbar < 109M⊙). We overview the results of systematic study of a hundred void dwarfs from the nearby Lynx-Cancer void. We describe the ongoing project aiming to form Nearby Void galaxy sample (R < 25 Mpc) over the whole sky. 1354 objects with distances less than 25 Mpc fall within 25 voids delineated by 460 luminous galaxies/groups. The void major sizes range from 13 to 37 Mpc. 1088 of 1354 void galaxies reside deeply in voids, having distances to the nearest luminous neighbour of 2–11 Mpc. 195 nearest void galaxies reside in the Local Volume. We summarize the main statistical properties of the new sample and outline the prospects of study of both, the void dwarf properties and the fine structure of voids.
The massive stellar population of IC 10
Authors: Corral Luis J. , García Miriam , Navarro Silvana G. , Herrero Artemio 
Published: October 2019

AbstractUsing photometric data available in the literature we want to identify the massive stars members of the metal-poor irregular galaxy IC 10 and the clusters and associations that they form. The census of the clusters and associations of these objects is needed to provide information about age and environment on this galaxy that is apparently going through a starburst phase.
A wide angle chemical survey of the Sagittarius dwarf Spheroidal galaxy
Authors: Sbordone L. , Monaco L. , Duffau S. , Bonifacio P. , Caffau E. 
Published: October 2019

AbstractWe present the status of an ongoing project to map the detailed chemical abundances of stars across the main body of the Sagittarius dwarf Spheroidal galaxy (Sgr dSph). The Sgr dSph is the closest known dwarf galaxy, and is being tidally destroyed by its interaction with the Milky Way (MW), leaving behind a massive stellar stream. Sgr dSph is a chemically outstanding object, with peculiar abundance ratios, clear center-outskirts abundance gradients, and spanning more than 3 orders of magnitude in metallicity. We present here detailed abundances from UVES@VLT spectra for more than 50 giants across 8 fields along the major and minor axes of Sgr dSph, and 5 more outside the galaxy main body, but possibly associated to its stellar stream.
Resonant Trapping of the Moving Groups G18-39 and G21-22 in the Galactic Halo
Authors: Schuster W. J. , Moreno E. , Fernández-Trincado J. G. 
Published: October 2019

AbstractOrbital resonances in the Galactic halo have been studied using the Galactic mass model of Pichardo et al. (2003, 2004), including a Galactic bar. For the two moving groups of the Galactic halo, G18-39 and G21-22 (Silva et al. 2012), the majority of stars in both groups appear trapped in two resonances over the Galactic plane, generated by the bar. We have taken the rotation speed of the bar, Ωb, as 45-55 km s-1 kpc-1. So, these two moving groups are part of stellar supergroups which populate these two resonances. The position of these two groups in the Bottlinger diagram can be explained by the mean (U,V) field generated by these two resonances crossing the solar vicinity, in contrast with the alternate explanation of Silva et al. (2012), based on the simulations of Meza et al. (2005), that these two groups, seen as two peaks in the U Galactic velocity, have been created by the accretion of a dwarf galaxy by the Milky Way, such as that of Ω Centauri.
Dwarf Galaxies and Cluster Environments
Authors: Hashimoto Yasuhiro , Henry J. Patrick , Böhringer Hans 
Published: October 2019

AbstractWe report an investigation of the properties of dwarf galaxies (Mr < -15) inside 26 clusters at z = 0.15 – 0.25, using the X-ray data from the Chandra archive, and optical images taken with Subaru Suprime-Cam. Our results include: 1. Investigation of the dwarf galaxy density distribution is sensitive to the background galaxies and the choice of colour selection of galaxies. 2. Cluster-centric dwarf-to-giant ratio is highly sensitive to the level of subtracted background galaxies. 3. A certain fraction of faint galaxies always remain undetected by the detection algorithm near the center of clusters, even after carefully treating the halo or extra diffuse light created by bright galaxies. The number of ‘undetected’ faint galaxies varies significantly from cluster to cluster, and even from pointing to pointing. 4. Dwarf galaxies extend up to 2 Mpc from the center in most clusters. Meanwhile, the distribution of blue dwarf galaxies extends more to the outside. 5. For a given colour, the spatial distributions of dwarf galaxies and giant galaxies become similar. Namely, the most of the radial distribution comes from the colour, rather than the size, of galaxies. 6. Relative to the NFW profile, all of the galaxy populations are showing a deficit near the cluster core (r < 0.3 Mpc). 7. The dwarf-to-giant ratio shows no variation against cluster measures such as the richness and X-ray luminosity, as well as various cluster X-ray characteristics related to possible dynamical status of clusters.
FOSSILs in the Galactic Halo
Authors: Grillmair Carl J. 
Published: October 2019

AbstractWe use a matched filter to detect compact groups of old, metal-poor stars that we term FOSSILs (Fragments of Old Stellar Systems in Limbo). With size scales on the order of 10 arcminutes, distances ranging from 2 to 200 kpc, and memberships ranging from a handful to several dozen stars, these FOSSILs stand out from the surrounding field and are presumably signatures of, or debris from, ancient star clusters and dwarf galaxies. They may be localized concentrations of stars within more extensive tidal streams, and in some cases may be the signatures of extant but heretofore undetected ultrafaint galaxies. Using magnitudes and colors from the Pan-STARRs survey, we detect ∼ 70 such FOSSILs at 5 σ or greater in a 2200 square degree region in the vicinity of the north Galactic pole. A subsample of more populous FOSSILs that could be candidate ultrafaint dwarf galaxies suggests a total population of 200 such objects within 200 kpc of the Galactic center. Spectroscopic and astrometric follow-up of these FOSSILs will be required to determine the nature of these structures, deepen our understanding of the make-up and accretion history of the Galactic halo, and perhaps alleviate the missing satellites problem.
Evolution of star-forming dwarf galaxies in different environments
Authors: Grossi Marco 
Published: October 2019

AbstractThe ubiquity of star-forming dwarf galaxies (SFDG) in the local Universe allows us to trace their evolution in all type of environments, from voids to rich clusters. SFDGs in low-density regions are still assembling their mass, they often show peculiar gas morphology and kinematics, likely associated to external gas accretion or galaxy interactions, and they can experience strong bursts of star formation. The most metal-poor SFDGs are found in the field and they are unique laboratories to investigate the star formation process in the low-metallicity regime, at conditions similar to their high-redshift analogues. On the other hand, SFDGs in intermediate- and high-density environments provide a key to understand the processes that remove their interstellar medium (ISM) and suppress star formation, leading to the different types of gas-poor early-type dwarfs. We review the most recent results on the properties of SFDGs at low and high galaxy densities focusing in particular on the impact of a cluster environment on their ISM components (dust, molecular, atomic and ionised gas). We analyse the population of SFDGs in the nearest rich clusters: Virgo, which is still in the process of assembly, and Fornax, which is more dynamically evolved, more compact and denser. We discuss how the different evolutionary stage of the two structures affects the properties of SFDGs.
CO / CI observations of N83C in the early stage of star formation in SMC with ALMA
Authors: Zahorecz Sarolta , Onishi Toshikazu , Muraoka Kazuyuki , Homma Aya , Harada Ryohei , Takada Shota , Maezawa Hiroyuki , Tokuda Kazuki , Saigo Kazuya , Kawamura Akiko , Mizuno Norikazu , Minamidani Tetsuhiro , Meixner Margaret , Indebetouw Remy , Sewilo Marta , Fukui Yasuo , Bolatto Alberto 
Published: October 2019

AbstractThe Magellanic Clouds offer the opportunity to obtain a spatially resolved view of external galaxies at reduced metallicity with no distance ambiguity. Our ALMA observations of the active star-forming region N83C in the Small Magellanic Cloud (SMC) revealed subparsec-scale molecular structures in 12CO and 13CO (2-1) emission Muraoka et al. (2017). We found strong CO peaks associated with Young Stellar Objects(YSOs) and derived a typical gas density of ∽104 cm−3 and gas temperature of 40-60 K from the excitation analysis. The high gas density and temperature are presumably due to the effect of the HII region under the low-metallicity environment. We have found that the column density ratios N(CI)/N(CO) are generally high throughout the cloud compared with the Galaxy, ranging from 0.2 to 2.0. A peak of the ratio is observed toward a CO peak associated with a massive protostar.