Variable stars in Local Group Galaxies - V. The fast and early evolution of the low-mass Eridanus II dSph galaxy

We present a detailed study of the variable star population of Eridanus II (Eri II), an ultra-faint dwarf galaxy that lies close to the Milky Way virial radius. We analyze multi-epoch g, r, i ground-based data from Goodman and the Dark Energy Camera, plus F475W, F606W, F814W space data from the Advanced Camera for Surveys. We report the detection of 67 RR Lyrae (RRL) stars and 2 Anomalous Cepheids, most of them new discoveries. With the RRL stars, we measure the distance modulus of Eri II, μ0 = 22.84 ± 0.05 mag (D⊙ = 370 ± 9 kpc) and derive a metallicity spread of 0.3 dex (0.2 dex intrinsic). The colour distribution of the horizontal branch (HB) and the period distribution of the RRL stars can be nicely reproduced by a combination of two stellar models of [Fe/H]=(−2.62, −2.14). The overall low metallicity is consistent with the red giant branch bump location, 0.65 mag brighter than the HB. These results are in agreement with previous spectroscopic studies. The more metal-rich RRL and the RRab stars have greater central concentration than the more metal-poor RRL and the RRc stars that are mainly located outside ∼1 rh. This is similar to what is found in larger dwarf galaxies such as Sculptor, and in agreement with an outside-in galaxy formation scenario. This is remarkable in such a faint dwarf galaxy with an apparently single and extremely short (<1 Gyr) star formation burst. Finally, we have derived new and independent structural parameters for Eri II and its star cluster using our new data that are in very good agreement with previous estimates.

Review on Image Recoloring Methods for Efficient Naturalness by Coloring Data Modeling Methods for Low Visual Deficiency

Recent research has discovered new applications for object tracking and identification by simulating the colour distribution of a homogeneous region. The colour distribution of an object is resilient when it is subjected to partial occlusion, scaling, and distortion. When rotated in depth, it may remain relatively stable in other applications. The challenging task in image recoloring is the identification of the dichromatic color appearance, which is remaining as a significant requirement in many recoloring imaging sectors. This research study provides three different vision descriptions for image recoloring methods, each with its own unique twist. The descriptions of protanopia, deuteranopia, and tritanopia may be incorporated and evaluated using parametric, machine learning, and reinforcement learning techniques, among others. Through the use of different image recoloring techniques, it has been shown that the supervised learning method outperforms other conventional methods based on performance measures such as naturalness index and feature similarity index (FSIM).

Col-OSSOS: Investigating Outlying Surfaces within the Kuiper Belt's Neutral Coloured Objects

<p>Within the outer Solar System exists the Kuiper belt. This Kuiper belt is made up of many icy planetesimals, the remaining relics of planet-forming bodies that failed to evolve into a planet beyond Neptune. The smaller members of the Kuiper belt (with <em>r</em> mag > 22) generally show linear and featureless spectra. Additionally, due to the dimness of these objects observing their spectra can be particularly difficult. Therefore, broadband photometry is often used to characterise their surfaces. The broadband photometry can be used as a proxy for composition, as it provides enough information to characterise the optical and near-infrared spectral slopes ofthese Kuiper Belt Object (KBO) surfaces.</p> <p>The Colours of the Outer Solar System Origins Survey (Col-OSSOS, Schwamb et al., 2019) took near-simultaneous <em>g-</em>, <em>r-</em> and <em>J-band</em> broadband photometry of a sample of KBOs with unprecedented precision using the Gemini North telescope. As with previous colour surveys (e.g. Tegler et al., 2016), they showed abimodal colour distribution in optical / near-infrared colours for the dynamically ‘hot’ population. We split this colour distribution into the ‘neutral’ coloured population with <em>(</em><em>g−r</em><em>)</em> < 0.75 and the ‘red’ coloured populationwith <em>(</em><em>g−r</em><em>)</em> ≥ 0.75.</p> <p>The preciseness of the colour measurements of Col-OSSOS has allowed the identification of several KBOs with outlying surface colours. These objects separated out from the rest of the neutral cloud in <em>(</em><em>g−r</em><em>)</em> versus <em>(r−J</em><em>)</em> colours, with <em>(</em><em>g−r</em><em>)</em> colour near solar colour. Using the Gemini North telescope in Hawaii we have taken extra photometry in the <em>i</em><em>−</em> and <em>z−</em><em>bands</em> for three of these objects (2013 JE64, 2013 JR65 and 2014 UL225). These additional filter observations will allow us to identify any possible broadband absorption features on these object’s surfaces that may have caused their outlying surface colours. Asteroid interloper 2004 EW95 (Seccull et al., 2018), along with some Jupiter Trojans and C-type asteroids (Bus & Binzel, 2002; DeMeo & Carry,2013) have been shown to have similar near solar neutral surfaces. In this presentation we will report resultsof the <em>griz</em> photometry of 2013 JE64, 2013 JR65 and 2014 UL225. We will make comparisons between these results and the photometry of previously identified outlying KBOs and comment on any possible similarities.</p> <p><strong>References</strong></p> <p>Bus, S. J., & Binzel, R. P. 2002, Icarus, 158, 146<br />DeMeo, F. E., & Carry, B. 2013, Icarus, 226, 723<br />Schwamb, M. E., Bannister, M. T., Marsset, M., et al. 2019, ApJS, 243, 12<br />Seccull, T., Fraser, W. C., Puzia, T. H., Brown, M. E., & Schönebeck, F. 2018, ApJ, Letters, 855, L26<br />Tegler, S. C., Romanishin, W., Consolmagno, G. J., & J., S. 2016, AJ, 152, 210</p>

Globular cluster systems of relic galaxies

ABSTRACT We analyse the globular cluster (GC) systems of a sample of 15 massive, compact early-type galaxies (ETGs), 13 of which have already been identified as good relic galaxy candidates on the basis of their compact morphologies, old stellar populations and stellar kinematics. These relic galaxy candidates are likely the nearby counterparts of high-redshift red nugget galaxies. Using F814W (≈I) and F160W (≈H) data from the WFC3 camara onboard the Hubble Space Telescope, we determine the total number, luminosity function, specific frequency, colour, and spatial distribution of the GC systems (GCSs). We find lower specific frequencies (SN < 2.5 with a median of SN = 1) than ETGs of comparable mass. This is consistent with a scenario of rapid, early dissipative formation, with relatively low levels of accretion of low-mass, high-SN satellites. The GC half-number radii are compact, but follow the relations found in normal ETGs. We identify an anticorrelation between the specific angular momentum (λR) of the host galaxy and the (I − H) colour distribution width of their GCSs. Assuming that λR provides a measure of the degree of dissipation in massive ETGs, we suggest that the (I − H) colour distribution width can be used as a proxy for the degree of complexity of the accretion histories in these systems.

Correlation between the rust colour distribution rate and corroded surface characteristics of galvanized steel wires

<p>This study investigated the correlation of the rust colour distribution rate provided by using a digital image colour analysis system and the corroded surface characteristics provided by using a non- contact surface mapping technique. The ratio of zinc-specific white rust to iron-specific red rust, which characterizes the corrosion status of bridge wires, can be quantified by introducing the digital image colour analysis system. Regarding the correlation between the rust colour distribution rate and the corrosion surface characteristics, it was found that the corrosion loss rate and the pit depth increase as the white rust rate decreases.</p>

60Co gamma irradiation-induced mutation in vegetatively propagated Philodendron erubescens 'Gold'.

Philodendron erubescens 'Gold', an ornamental plant and a popular climber with brilliant greenish yellow leaves, is used in indoor gardening and landscaping. It is commonly propagated through vegetative cuttings, thus incorporation of new traits through conventional breeding is impracticable. As commercial floriculture always demands novel varieties, this study was carried out to induce mutation in P. erubescens 'Gold' leaves using gamma- ray irradiation. Rooted cuttings (n = 200) of P. erubescens 'Gold' were subjected to 70 Gy, 100 Gy and 150 Gy gamma-rays and recovered on a propagator. Surviving shoots were transferred to pots. Regenerated shoots were multiplied vegetatively and ten M1 lines were maintained as M1-1 to M1-10 for 12 generations (M1V12) to evaluate growth and morphological variations along with their genetic stability. Of all 70 Gy and 100 Gy treated cuttings, 24 and two, respectively, survived after 6 months. Most of the irradiated plants had lost regeneration ability except for two M1 plants, which also showed comparatively reduced growth (one leaf in 45 days). Only one regenerated M1 plant showed morphological variation in its leaves and it was multiplied and maintained as lines. Several variations, including characteristics of leaves (shape, size, colour), stems (internodal length and branching) and plant stature, were observed among M1 lines and in subsequent vegetative generations. Leaves had three different colour patches, but neither the colour nor its distribution pattern was uniform or stable. The M1-4 line showed the highest stability of colour distribution in leaves; the colour composition of its leaves ranged as 0-10% dark bluish green, 60-90% strong yellow green and 10-30% brilliant greenish yellow throughout the 12 generations. This study demonstrates that gamma irradiated P. erubescens 'Gold' line M1-4 can be a promising mutant to develop as a new Philodendron cultivar.

New Measure of Economic Development Based on the Four-Colour Theorem

The location quotient is one of the basic quantitative tools for identifying the regional poles and the turnpikes of economic growth in spatial economy. The disadvantage of this traditional measure is the limited scope of economic information contained in it. The new measure of economic development proposed in the article encompasses a complex spectrum of phenomena in one number, as it takes into account the influence of the public administration sector, as well as top technology in the form of ICT and its practical business models. It also takes into account the digital prosumption and the platforms for participation. The participation platforms in the public administration sector are the websites of municipal public administration offices. A cluster analysis was used to distinguish four quality classes of these websites. These classes were assigned four different colours, which were then used to draw up a map of the selected province. Each municipality is marked with a colour that corresponds to the quality class of the website of the state administration office operating on its territory. The colour system resulting from the four-colour theorem and the corresponding dual graph play the role of a reference system in relation to each empirical colour distribution and another dual graph related to it. The measure of the economic development of a region is the degree of reduction of the dual graph corresponding to the empirical distribution of colours, which identifies the actual growth poles and determines the routes of growth. The presented indicator better and more precisely identifies poles and routes of economic growth than the traditional location quotient.

Variations in reproductive and egg traits correlation estimates of two strains of Archachatina marginata snails (var. ovum and var. saturalis) and crosses

A study was conducted to ariations in the reproductive traits and egg traitscorrelation estimates of the two strains of Archachatina marginata snails (var. ovum and var. saturalis) and their crosses. Ninety sexually mature A. marginata snails, forty-five each of the two strains (var. saturalis and var. ovum) were selected from a base population for the study. he live weight of the snails ranged from 256.43 – 566.25 g for both strains. Selection of the snails was based on active appearance and lack of injury on the foot and on shells. The snails were randomly allotted into three mating models (treatments) of 30 each of var. saturalis, var. ovum and mixed strains (at 15 var. ovum : 15 var. saturalis). The models were designated as homozygous var. ovum main cross (AMO X AMO), homozygous var. saturalis main cross (AMS X AMS) and heterozygous (var. ovum x var. saturalis) cross (AMO X AMS). Each of the three models was replicated 15 times with two snails to a tub/cell for purposes of reproduction. Results from the study showed that the three mating models expressed significant (P<0.05) differences in the reproductive traits evaluated. Whereas some of the traits were not significantly (P>0.05) different between the AMO X AMO and AMO X AMS mating models, significant (P<0.05) differences existed between all the traits when the AMS AMS mating model was compared with the AMO X AMO and AMO X AMS mating models. The clutch size ranged from 7.00±0.35 (AMS X AMS) through 9.40±0.35 (AMO X AMS) to 9.90±0.35 (AMO X AMO), while the values for mean egg weight at lay ranged from 1.59±0.03 g (AMS X AMS) through 1.78±0.03 g (AMO X AMO) to 1.79±0.03 g (AMO X AMS). Percent hatchability value was highest in the AMO X AMO mating model (93.30 %), followed by the AMS X AMS mating model (91.10 %), while the AMO X AMS mating model recorded the lowest value (88.50 %). Percent survivability value was highest in the AMO X AMS mating model (84.00 %), followed by the AMO X AMO mating model (82.00 %), while the AMS X AMS mating model recorded the lowest value (80.00 %). The egg traits correlation estimates (rp) revealed that except for one pair of trait each in the mating models, all the other pairs of traits expressed positive and significant correlation coefficients/values. The AMO X AMS mating model recorded the highest correlation (rp) value (0.826) for the pair of ELH vs EWH, while the AMS X AMS mating model recorded the lowest correlation (rp) value (– 0.058) for the pair of ELH vs CSE. The percent egg shell colour distribution showed that the shell of eggs laid by the homozygous crosses (AMO X AMO and AMS X AMS) expressed two colours. The egg shell of eggs laid by AMO X AMO mating model expressed mikado yellowand maize yellow colours, while those laid by AMS X AMS mating model expressed Mikado yellow and amber colours. The shell of eggs laid by the heterozygous cross however expressed three colours; mikado yellow, maize yellow and amber. Based on the reproductive traits results, it could be recommended that the AMO X AMS mating model be adopted by farmers for optimum production and returns on investment.

The Colour Distribution Of The Low Inclination Trans-Neptunian Objects

&lt;p&gt;The low-inclination component of the classical Kuiper Belt is thought to be the only population of trans-Neptunian bodies that formed in-situ (Parker et al., 2010). This population, often referred to as the cold classical objects, exhibits a&amp;#160; ~30% observed binary fraction, much higher than for other trans-Neptunian objects (TNOs; Noll et al., 2008). The majority of cold classicals belong to the Very Red (VR) class of the bimodal TNO compositional taxonomy (Fraser and Brown, 2012). Though recently, a population of Less Red (LR) members has been identified, exhibiting a 100% binary fraction (Fraser et al., 2017). These so-called blue binaries are thought to be survivors of a push-out process that occurred during a smooth phase of Neptune&amp;#8217;s outward migration.&amp;#160;&lt;/p&gt;&lt;p&gt;Here we report 20 new (g-r) and (r-J) colours of cold classical objects gathered as part of the Colours of the Outer Solar System Origins Survey (Col-OSSOS; Schwamb et al., 2019), bringing the total sample of cold classicals with measured colours to 21 with simultaneous optical and NIR colours, and 103 cold classical TNOs with optical colours alone. In this sample, 29 objects have been identified as binary (Parker, A., personal communication).&lt;/p&gt;&lt;p&gt;Cold classical colours span the full range of optical-NIR colours exhibited by the dynamically excited TNO populations, though they strongly favour red objects;&amp;#160; the VR:LR ratio is ~12 compared to ~3 for the excited TNOs. Moreover, the VR cold classicals have a redder colour distribution than the VR excited TNOs, with the former exhibiting a mean (g-r)~0.95 and the latter, a mean (g-r)~0.8.&lt;/p&gt;&lt;p&gt;The optical colour distribution of binary cold classicals is significantly different than that of the single (or unresolved) cold classical systems (see Figure 1), with the binary sample exhibiting a tail of lower spectral slopes than is found in the sample of singles. The Kolmogorov-Smirnov test comparing the optical colour distributions of the single and binary samples says that there is a only a 0.3% chance the two samples share the same colour distribution. The Col-OSSOS sample on its own shows a similar result, with a 2% probability of the null hypothesis. This argues for a different origin of some or all of the binary cold classicals over the unresolved or single objects population, and is compatible with the hypothesis that the blue binaries are contaminants having been pushed out from regions closer to the Sun.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;img src=&quot;https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.9f0a8cc182fe54421592951/sdaolpUECMynit/0202CSPE&amp;app=m&amp;a=0&amp;c=6e8006c0e65c3c057a5d59b961c13cde&amp;ct=x&amp;pn=gnp.elif&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Figure 1:&lt;/strong&gt; cumulative optical colour distributions of the single (or unresolved; solid) and binary (dashed) cold classical TNOs. The vertical line demarks the division between less red and very red compositional classes. Spectral slope is reported in percent reddening per 100 nm normalized in the V-band.&lt;/p&gt;

The first detection of ultra-diffuse galaxies in the Hydra I cluster from the VEGAS survey

In this paper, we report the discovery of 27 low-surface brightness galaxies, of which 12 are candidates for ultra-diffuse galaxies (UDG) in the Hydra I cluster, based on deep observations taken as part of the VST Early-type Galaxy Survey (VEGAS). This first sample of UDG candidates in the Hydra I cluster represents an important step in our project that aims to enlarge the number of confirmed UDGs and, through study of statistically relevant samples, constrain the nature and formation of UDGs. This study presents the main properties of this class of galaxies in the Hydra I cluster. For all UDGs, we analysed the light and colour distribution, and we provide a census of the globular cluster (GC) systems around them. Given the limitations of a reliable GC selection based on two relatively close optical bands only, we find that half of the UDG candidates have a total GC population consistent with zero. Of the other half, two galaxies have a total population larger than zero at 2σ level. We estimate the stellar mass, the total number of GCs, and the GC specific frequency (SN). Most of the candidates span a range of stellar masses of 107 − 108 M⊙. Based on the GC population of these newly discovered UDGs, we conclude that most of these galaxies have a standard or low dark matter content, with a halo mass of ≤1010 M⊙.