What is Important? Morphological Asymmetries are Useful Predictors of Star Formation Rates of Star-forming Galaxies in SDSS Stripe 82

The morphology and structure of galaxies reflect their star formation and assembly histories. We use the framework of mutual information (MI) to quantify the interdependence among several structural variables and to rank them according to their relevance for predicting the specific star formation rate (SSFR) by comparing the MI of the predictor variables with the SSFR and penalizing variables that are redundant. We apply this framework to study ∼3700 face-on star-forming galaxies (SFGs) with varying degrees of bulge dominance and central concentration and with stellar mass M ⋆ ≈ 109 M ⊙−5 × 1011 M ⊙ at redshift z = 0.02–0.12. We use the Sloan Digital Sky Survey (SDSS) Stripe 82 deep i-band imaging data, which improve measurements of asymmetry and bulge dominance indicators. We find that star-forming galaxies are a multiparameter family. In addition to M ⋆, asymmetry emerges as the most powerful predictor of SSFR residuals of SFGs, followed by bulge prominence/concentration. Star-forming galaxies with higher asymmetry and stronger bulges have higher SSFR at a given M ⋆. The asymmetry reflects both irregular spiral arms and lopsidedness in seemingly isolated SFGs and structural perturbations by galaxy interactions or mergers.

Jupiter's Interior as Revealed by Juno

Jupiter is in the class of planets that we call gas giants, not because they consist of gas but because they were primarily made from hydrogen-helium gas, which upon gravitational compression becomes a metallic fluid. Juno, in orbit about Jupiter since 2016, has changed our view: The gravity data are much improved, and the simplest interpretation of the higher order even harmonics implies that the planet may have a diluted central concentration of heavy elements. Jupiter has strong winds extending to perhaps ∼3,000-km depth that are evident in the odd zonal harmonics of the gravity field. Jupiter's distinctive magnetic field displays some limited local structure, most notably the Great Blue Spot (a region of downward flux near the equator), and some evidence for secular variation, possibly arising from the winds. However, Juno is ongoing; it has not answered all questions and has posed new ones. ▪ Juno's mission reveals Jupiter's interior. ▪ A core exists but is diluted by hydrogen. ▪ The mission revealed wind depth and magnetic field.

VV 655 and NGC 4418: Implications of an interaction for the evolution of a LIRG

Context. VV 655, a dwarf irregular galaxy with HI tidal debris, is a companion to the lenticular luminous infrared galaxy (LIRG) NGC 4418. NGC 4418 stands out among nearby LIRGs due to its dense central concentration of molecular gas and the dusty, bi-polar structures along its minor axis suggestive of a wind driven by a central starburst and possible nuclear activity. Aims. We seek to understand the consequences of the ongoing minor interaction between VV 655 and NGC 4418 for the evolution of the LIRG. Specifically, we consider the origin of the gas supply responsible for the unusual nuclear properties of NGC 4418. Methods. We investigate the structural, kinematic, and chemical properties of VV 655 and NGC 4418 by analyzing archival imaging data and optical spectroscopic observations from the SDSS-III and new spectra from SALT-RSS. We characterize their gas-phase metal abundances and spatially resolved, ionized gas kinematics to better understand whether gas transfer between VV 655 and NGC 4418 resulted in the highly obscured nucleus of the LIRG. Results. The gas-phase metallicity in NGC 4418 significantly exceeds that in VV 655. No kinematic disturbances in the ionized gas are observed along the minor axis of NGC 4418, but we see evidence for ionized gas outflows from VV 655 that may increase the cross-section for gas stripping in grazing collisions. A faint, asymmetric outer arm is detected in NGC 4418 of the type normally associated with galaxy-galaxy interactions. Conclusions. The simplest model suggests that the minor interaction between VV 655 and NGC 4418 produced the unusual nuclear properties of the LIRG via tidal torquing of the interstellar medium of NGC 4418 rather than through a significant gas transfer event. In addition to inducing a central concentration of gas in NGC 4418, this interaction also produced an enhanced star formation rate and an outer tidal arm in the LIRG. The VV 655-NGC 4418 system offers an example of the potential for minor collisions to alter the evolutionary pathways of giant galaxies.

Star formation in low-redshift cluster dwarf galaxies

ABSTRACT Evolution of galaxies in dense environments can be affected by close encounters with neighbouring galaxies and interactions with the intracluster medium. Dwarf galaxies (dGs) are important as their low mass makes them more susceptible to these effects than giant systems. Combined luminosity functions (LFs) in the r and u band of 15 galaxy clusters were constructed using archival data from the Canada–France–Hawaii Telescope. LFs were measured as a function of clustercentric radius from stacked cluster data. Marginal evidence was found for an increase in the faint-end slope of the u-band LF relative to the r-band with increasing clustercentric radius. The dwarf-to-giant ratio (DGR) was found to increase toward the cluster outskirts, with the u-band DGR increasing faster with clustercentric radius compared to the r-band. The dG blue fraction was found to be ∼2 times larger than the giant galaxy blue fraction over all clustercentric distance (∼5σ level). The central concentration (C) was used as a proxy to distinguish nucleated versus non-nucleated dGs. The ratio of high-C to low-C dGs was found to be ∼2 times greater in the inner cluster region compared to the outskirts (2.8σ level). The faint-end slope of the r-band LF for the cluster outskirts (0.6 ≤ r/r200 < 1.0) is steeper than the Sloan Digital Sky Survey field LF, while the u-band LF is marginally steeper at the 2.5σ level. Decrease in the faint-end slope of the r- and u-band cluster LFs towards the cluster centre is consistent with quenching of star formation via ram pressure stripping and galaxy–galaxy interactions.

Selection of resistant plants for the biotic stage of the recultivation of the dump of the Central concentrating mill "Chervonogradska" (Lviv region)

The properties of the substrate and microclimate conditions were analyzed on various elements of the mesorelief of the dump of Central concentration mill "Chervonogradska". The most adverse conditions were found at the top of the dump and its terraces due to high intensity of lighting, temperature, high content of heavy metals in substrates and their actual acidity. It was shown that Pinus sylvestris L. is a promising species for the biotic recultivation stage for terraces of dumps. We recommended to use perennial grass root species of plants, e.g. Calamagrostis epigeios (L.) Roth and Sorghum halepense (L.) Pers., for recultivation a slopes of dumps. The Petasites hibridus L. and Phragmites australis Cav. Trin ex Steud. are offered for the renovation of the bases and microhardness of the dumps with sufficient moisture. The high remediation ability of plants and their affiliation by the environmental groups to heliophytes, thermophiles, acidophiles, oligotrophes and xeromezophytes are the main requirements for reclamation plants on the non-renovated dumps.

Morphology in Austroasiatic Languages

The languages of the Austroasiatic (AA) language family share a core set of derivational prefixes and infixes that are largely fossilized. Beyond these, there is a wide range of morphological features throughout these more than 160 languages. Of the 13 branches of AA, there is a geographically central concentration of branches with predominantly isolating morphology (Khmeric, Monic, Vietic, and Pearic), while geographically peripheral branches have more complex morphology (Aslian and Khasic), and some with inflectional morphology (Munda and Nicobaric). Other branches are typologically between, largely lacking inflectional morphology (i.e., systematic, productive grammatical morphology) but having a somewhat more complex range of morphological features (Katuic, Bahnaric, Palaungic, Khmuic, and Mangic), including those with some grammatical functions. Other than Munda and Nicobaric, most AA languages have iambic word-level stress and have only prefixes and infixes while lacking suffixes. This has resulted in a collapsing of older morphological material, while new affixes, with new morphosemantic functions, emerge. Alternating reduplication, in which complete prosodic templates are copied but various segments are alternated, is a common word-formation strategy and sometimes combines with prefixes and affixes. While lexical compounds are common, so are pseudo-compounds with near affix-like semantic, and sometimes phonological, features. Overall, while monomorphemic words are common among the more isolating types of AA languages, ample linguistic descriptions show a substantially wider range of morphological complexity throughout the AA language family.

A DECam view of the diffuse dwarf galaxy Crater II: the colour–magnitude diagram

ABSTRACT We present a deep Blanco/DECam colour–magnitude diagram (CMD) for the large but very diffuse Milky Way satellite dwarf galaxy Crater II. The CMD shows only old stars with a clearly bifurcated subgiant branch (SGB) that feeds a narrow red giant branch. The horizontal branch (HB) shows many RR Lyrae and red HB stars. Comparing the CMD with [Fe/H] = −2.0 and [α/Fe] = + 0.3 alpha-enhanced BaSTI isochrones indicates a mean age of 12.5 Gyr for the main event and a mean age of 10.5 Gyr for the brighter SGB. With such multiple star formation events Crater II shows similarity to more massive dwarfs that have intermediate age populations, however for Crater II there was early quenching of the star formation and no intermediate age or younger stars are present. The spatial distribution of Crater II stars overall is elliptical in the plane of the sky, the detailed distribution shows a lack of strong central concentration, and some inhomogeneities. The 10.5 Gyr subgiant and upper main-sequence stars show a slightly higher central concentration when compared to the 12.5 Gyr population. Matching to Gaia DR2 we find the proper motion of Crater II: μαcos δ = −0.14 ± 0.07, μδ = −0.10 ± 0.04 mas yr−1, approximately perpendicular to the semimajor axis of Crater II. Our results provide constraints on the star formation and chemical enrichment history of Crater II, but cannot definitively determine whether or not substantial mass has been lost over its lifetime.

Stellar systems following the R1/m luminosity law

We expand our previous analytical and numerical studies of the family of Sérsic models, which are routinely used to describe early-type galaxies and the bulges of spiral galaxies. In particular, we focus on the total energy budget, an important dynamical property that has not been discussed in detail in previous works. We use two different methods to calculate the total energy for the Sérsic model family that result in two independent expressions that can be used along the entire sequence of Sérsic models. We use these expressions to investigate whether the Spitzer concentration index is a reliable measure for the intrinsic 3D concentration of galaxies, and we conclude that it is not a very useful measure for the central concentration. The popular Third Galaxy Concentration index, on the other hand, is shown to be a reliable measure for the intrinsic 3D concentration, even though it is based on the surface brightness distribution and not on the intrinsic 3D density.

Disintegration of active asteroid P/2016 G1 (PANSTARRS)

We report on the catastrophic disintegration of P/2016 G1 (PANSTARRS), an active asteroid, in April 2016. Deep images over three months show that the object is made up of a central concentration of fragments surrounded by an elongated coma, and presents previously unreported sharp arc-like and narrow linear features. The morphology and evolution of these characteristics independently point toward a brief event on 2016 March 6. The arc and the linear feature can be reproduced by large particles on a ring, moving at ~2.5 m s−1. The expansion of the ring defines a cone with a ~40° half-opening. We propose that the P/2016 G1 was hit by a small object which caused its (partial or total) disruption, and that the ring corresponds to large fragments ejected during the final stages of the crater formation.

Expression of genes encoding zona pellucida glycoproteins and cortical granule distribution in porcine oocytes isolated from small and medium follicles in relation to puberty status of donors

The zona pellucida proteins belong to a group of proteins that regulate the processes of gamete recognition, interaction, and fusion, since they are recognized as primary and secondary sperm receptors. It is suggested that cortical granule distribution is significantly associated with the zona pellucida structure and membrane preparation to cortical and acrosome reaction. Therefore, this study investigated the zona pellucida marker gene expression (ZP2 and ZP4 protein) in relation to cortical granules distribution in oocytes and puberty status of donors. Oocytes were collected from adult cyclic sows (isolated from medium and small follicles) and juvenile gilts (isolated only from small follicles). The oocytes were examined by RT-qPCR and by confocal microscopy. The expression of genes for ZP2 and ZP4 protein in oocytes collected from small follicles from cycling sows was higher in comparison to oocytes from medium follicles or oocytes collected from small follicles from juvenile gilts (P < 0.001). We also observed increased expression of both ZP2 and ZP4 mRNA in oocytes collected from small follicles (juvenile gilts) as compared to medium follicles (cycling sows) (P < 0.001). Moreover, we found a difference in the distribution of cortical granules. In oocytes from medium follicles, the peripheral localization of cortical granules was twice higher than their central concentration. However, in oocytes derived from small follicles (cyclic sows) cortical granules in comparison to oocytes from medium follicles were more centrally localized (P < 0.05). It has been suggested that the donor puberty status and the size of follicles significantly influenced the zona pellucida gene expression and cortical granule localization in porcine oocytes. This is accompanied by fertilization specificity and fertilizability of porcine oocytes in vitro.