Tracing satellite planes in the Sculptor group Martínez-Delgado, David; Makarov, Dmitry; Javanmardi, Behnam ...
Astronomy and astrophysics (Berlin),
08/2021, Letnik:
652
Journal Article
Recenzirano
Context.
In recent years, a new generation of large-scale imaging surveys have probed wide field regions for the first time around some nearby galaxies in an unprecedentedly low surface-brightness ...regime (∼28.0−29.0 mag arcsec
−2
). This provides the chance to discover very faint dwarf satellites by means of systematic visual inspection of these public deep images.
Aims.
In this paper, we report the first results of a systematic survey of faint dwarf spheroidal galaxies in the vicinity of the bright late-type spiral galaxy NGC 253 by means of a visual inspection of the images taken by the Dark Energy Survey.
Methods.
We performed a new NGC 253 satellite search using co-added image cutouts reprocessed in the DESI Legacy image surveys. We used
GALFIT
software to investigate the photometric and structural properties of three dwarf galaxies.
Results.
We report the discovery of three new dwarf galaxies in the vicinity of the brightest member of the Sculptor filament, the late-type spiral NGC 253, located at a distance of 3.7 Mpc towards Anti-Virgo. We name them Do II, Do III, and Do IV. Assuming they are companions of NGC 253, their total absolute
V
-magnitudes fall in the −7 to −9 mag range, which is typical for dwarf satellites in the local Universe. The central surface brightness tends to be extremely low for all three discovered dwarfs and falls roughly in the range of 25−26 mag arcsec
−2
in
g
-band. Using known data on distances and velocities of galaxies, we estimate the total virial mass of the NGC 253 group to be 8 × 10
11
M
⊙
, which gives a virial radius of
R
200
= 186 kpc and a turn-around radius of 706 kpc. We also discuss the possible existence of a spatially flattened and velocity-correlated satellite system around NGC 253. This large-scale structure is orientated almost edge-on to the line of sight. The possible plane of satellites is only 31 kpc thick with a minor-to-major axis ratio of 0.14. Four out of five galaxies with measured velocities follow a common velocity trend similar to those observed in the planes of satellites around the Andromeda and Centaurus A galaxies. However, the small number of galaxies with known velocities prevents us from reaching a definitive conclusion about the formation scenario of the structure and its possible relation to the surrounding cosmic web.
We present an extragalactic perspective of an extended stellar tidal stream wrapping around the edge-on spiral galaxy NGC 5907. Our deep images reveal for the first time a large-scale complex of ...arcing loops that is an excellent example of how low-mass satellite accretion can produce an interwoven, rosette-like structure of debris dispersed in the halo of its host galaxy. The existence of this structure, which has probably formed and survived for several gigayears, confirms that halos of spiral galaxies in the local universe may still contain a significant number of galactic fossils from their hierarchical formation. To examine the validity of the external accretion scenario, we present N-body simulations of the tidal disruption of a dwarf galaxy-like system in a disk galaxy plus dark halo potential that demonstrate that most of the tidal features observed in NGC 5907 can be explained by a single accretion event. Unfortunately, with no kinematic data and only the projected geometry of the stream as a constraint, the parameters of our model are considerably degenerate and, for now, must be considered illustrative only. Interestingly, NGC 5907 has long been considered a prototypical example of a warped spiral in relative isolation. The presence of an extended tidal stream challenges this picture and suggests that the gravitational perturbations induced by the stream progenitor must be considered as a possible cause for the warp. The detection of an old, complex tidal stream in a nearby galaxy with rather modest instrumentation points to the viability of surveys to find extragalactic tidal substructures around spiral galaxies in the Local Volume (<15 Mpc), with the prospect of obtaining a census with enough statistical significance to be compared with cosmological simulations.
Summary
Garlic peel extracts (GPE) are known to have excellent physiological activity, but research on the pre‐processing of garlic peel (GP) to enhance their bioactivity is limited. The aim of this ...study was to evaluate the effect of two pretreatments applied to GP, such as fermentation with
Lactobacillus plantarum
and heat processing (10 min roasting) and two extraction solvents (70% v/v ethanol and methanol), on the total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity (AC), and antimicrobial activity (AA) of GPE. Results showed that GPE contained appreciable quantities of TPC (50.41 ± 0.19 mg
GAE
/g) and TFC (47.58 ± 1.69 mg
GAE
/g), but were further improved by both biological and thermal pretreatments along with their AC and AA against food‐spoilage strains (
Escherichia coli
,
Salmonella typhimurium
,
Staphylococcus aureus
, and
Listeria innocua
). Ethanolic extract of 48 h‐fermented GP achieved the highest TPC (140.65 ± 0.47 mg
GAE
/g), TFC (68.8 ± 1.80 mg
QE
/g), TEAC‐DPPH (288.88 ± 6.98 μmol
TE
/g), TEAC‐ABTS (638.39 ± 5.35 μmol
TE
/g), and the lowest MIC (1.25 ± 0.0 mg/mL), showing that the increase in TPC was strong‐positive correlated to AC (Pearson's
r
> 0.97) and to AA (Pearson's
r
> 0.90). These findings revealed an innovative approach for the valorisation of garlic residues through a bioconversion process, which enhances their potential as a source of antioxidant and antimicrobial agents for possible food applications.
Organic compounds containing the F or B elements in their structures have recently attracted the interest of the chemists and medicinal chemists because their improved biological properties displayed ...in comparison to their non-fluorinated or non-borinated parent structures. It is widely been documented that curcumine (CUR) have a high biological potential as antioxidant, anti-inflammatory and anticancer agent, among others, but some drawbacks related to its unfavorable bio-physicochemical properties have prevented its applicability as chemotherapeutic drug. Nevertheless, recent studies have shown that the introduction of the BF2 functionality in its structure (i.e. CUR-BF2 adducts) and analogues have significantly improved their biological properties, mainly, their anticancer and antibiotic activities.
On the other hand, the BF2-adduct BODIPY (i.e. 4,4-difluoro-4-bora-3a-azonia-4a-aza-s-indacene) and derivatives are widely known by their outstanding photophysical properties displayed. However, recently it have increased the interest in such structures, but this time, for the biological properties that these fluorescent compounds are also shown, as convenient probes for diverse biological targets.
Focusing on the above findings, we were interested into compile, in this review article, the literature documented since 2000–2020 exclusively engaged with the synthetic strategies established for the synthesis of curcumine-BF2 adducts, BODIPY and their related derivatives, in which the biological properties displayed by such structures have been highlighted. Remarkably, the biological activities displayed by the aforementioned BF2-based compounds are mainly related with cell imaging studies, biomolecules recognition and labels, antibiotic properties and antiproliferative agents, which were conveniently used to organize them in concise Tables and Schemes to facilitate their comparisons, and to underscore the key points of the present review.
We use N-body simulations to explore the possibility that the Sagittarius (Sgr) dwarf galaxy was originally a late-type, rotating disc galaxy, rather than a non-rotating, pressure-supported dwarf ...spheroidal galaxy, as previously thought. We find that bifurcations in the leading tail of the Sgr stream, similar to those detected by the SDSS survey, naturally arise in models where the Sgr disc is misaligned with respect to the orbital plane. Moreover, we show that the internal rotation of the progenitor may strongly alter the location of the leading tail projected on the sky, and thus affect the constraints on the shape of the Milky Way dark matter halo that may be derived from modelling the Sgr stream. Our models provide a clear, easily tested prediction; although tidal mass stripping removes a large fraction of the original angular momentum in the progenitor dwarf galaxy, the remnant core should still rotate with a velocity amplitude ∼20 km s−1 that could be readily detected in future, wide-field kinematic surveys of the Sgr dwarf.
Using deep photometric data from Wide Field Camera at the Isaac Newton Telescope and Wide Field Imager at the ESO 2.2-m telescope we measure the outer number density profiles of 19 stellar clusters ...located in the inner region of the Milky Way halo (within a Galactocentric distance range of 10-30 kpc) in order to assess the impact of internal and external dynamical processes on the spatial distribution of stars. Adopting power-law fitting templates, with index −γ in the outer region, we find that the clusters in our sample can be divided in two groups: a group of massive clusters (≥105 M⊙) that has relatively flat profiles with 2.5 < γ < 4, and a group of low-mass clusters (≤105 M⊙), with steep profiles (γ > 4) and clear signatures of interaction with the Galactic tidal field. We refer to these two groups as 'tidally unaffected' and 'tidally affected', respectively. Our results also show a clear trend between the slope of the outer parts and the half-mass density of these systems, which suggests that the outer density profiles may retain key information on the dominant processes driving the dynamical evolution of globular clusters.
The genetic profile that is needed to identify talents has been studied extensively in recent years. The main objective of this investigation was to approach, for the first time, the study of genetic ...variants in several polygenic profiles and their role in elite endurance and professional football performance by comparing the allelic and genotypic frequencies to the non-athlete population. In this study, genotypic and allelic frequencies were determined in 452 subjects: 292 professional athletes (160 elite endurance athletes and 132 professional football players) and 160 non-athlete subjects. Genotyping of polymorphisms in liver metabolisers (CYP2D6, GSTM1, GSTP and GSTT), iron metabolism and energy efficiency (HFE, AMPD1 and PGC1a), cardiorespiratory fitness (ACE, NOS3, ADRA2A, ADRB2 and BDKRB2) and muscle injuries (ACE, ACTN3, AMPD1, CKM and MLCK) was performed by Polymerase Chain Reaction-Single Nucleotide Primer Extension (PCR-SNPE). The combination of the polymorphisms for the "optimal" polygenic profile was quantified using the genotype score (GS) and total genotype score (TGS). Statistical differences were found in the genetic distributions between professional athletes and the non-athlete population in liver metabolism, iron metabolism and energy efficiency, and muscle injuries (p<0.001). The binary logistic regression model showed a favourable OR (odds ratio) of being a professional athlete against a non-athlete in liver metabolism (OR: 1.96; 95% CI: 1.28-3.01; p = 0.002), iron metabolism and energy efficiency (OR: 2.21; 95% CI: 1.42-3.43; p < 0.001), and muscle injuries (OR: 2.70; 95% CI: 1.75-4.16; p < 0.001) in the polymorphisms studied. Genetic distribution in professional athletes as regards endurance (professional cyclists and elite runners) and professional football players shows genetic selection in these sports disciplines.
Non-optimal vaginal microbiota, as observed in bacterial vaginosis (BV), is typically characterized by a depletion of beneficial lactobacilli and an abundance of numerous anaerobes. These non-optimal ...conditions are associated with subclinical cervicovaginal inflammation and an increased risk of HIV infection compared to women colonized with optimal vaginal microbiota dominated by lactobacilli. Lactic acid (LA) is a major organic acid metabolite produced by vaginal lactobacilli that elicits anti-inflammatory effects from cervicovaginal epithelial cells and is dramatically depleted during BV. However, it is unclear if LA retains its anti-inflammatory activity in the presence of vaginal microbiota metabolites comprising short chain fatty acids (SCFAs) and succinic acid, which are also produced by an optimal vaginal microbiota. Furthermore, the immunomodulatory effect of SCFAs and succinic acid on cervicovaginal epithelial cells at higher concentrations present during BV is unknown. Here we report that in the presence of physiologically relevant concentrations of SCFAs and succinic acid at pH 3.9 (as found in women with lactobacillus-dominated microbiota) LA induced an anti-inflammatory state in cervicovaginal epithelial cells and inhibited inflammation elicited by the toll-like receptor (TLR) agonists polyinosinic:polycytidylic acid and Pam3CSK4. When cervicovaginal epithelial cells were treated with a vaginal microbiota metabolite mixture representative of BV, containing a lower concentration of LA but higher concentrations of SCFA/succinic acid at pH 7, no anti-inflammatory was observed. Rather, the vaginal microbiota metabolite mixture representative of BV dysregulated the immune response of cervicovaginal epithelial cells during prolonged and sustained treatments. This was evidenced by increased basal and TLR-induced production of pro-inflammatory cytokines including tumor necrosis factor-α, but decreased basal production of chemokines including RANTES and IP-10. Further characterization of individual components of the BV vaginal microbiota mixture suggested that acetic acid is an important vaginal microbiota metabolite capable of eliciting diverse immunomodulatory effects on a range of cervicovaginal epithelial cell targets. These findings indicate that elevated levels of SCFAs are a potential source of cervicovaginal inflammation in women experiencing BV, and support the unique anti-inflammatory properties of LA on cervicovaginal epithelial cells as well as a role for LA or LA-producing lactobacilli to reverse genital inflammation associated with increased HIV risk.
Abstract
We present Dark Energy Camera imaging for the peculiar Galactic globular clusters NGC 1851, NGC 1904 (M 79), NGC 2298 and NGC 2808. Our deep photometry reveals that all the clusters have an ...important contribution of stars beyond their King tidal radii and present tails with different morphologies. We have also explored the surroundings of the clusters where the presence of the Canis Major overdensity and/or the low Galactic latitude Monoceros ring at d⊙ ∼ 8 kpc is evident. A second stellar system is found at d⊙ ∼ 17 kpc and spans at least 18 deg × 15 deg in the sky. As one of the possible scenarios to explain that feature, we propose that the unveiled system is part of Monoceros explained as a density wave moving towards the outer Milky Way. Alternatively, the unveiled system might be connected with other known halo substructures or associated with the progenitor dwarf galaxy of NGC 1851 and NGC 1904, which are widely considered accreted globular clusters.
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