We present two new catalogues of superclusters of galaxies out to a redshift of z = 0.15, based on the Abell/ACO cluster redshift compilation maintained by one of us (HA). The first of these ...catalogues, the all-sky Main SuperCluster Catalogue (MSCC), is based on only the rich (A-) Abell clusters, and the second one, the Southern SuperCluster Catalogue (SSCC), covers declinations δ < −17° and includes the supplementary Abell S-clusters. A tunable Friends-of-Friends algorithm was used to account for the cluster density decreasing with redshift and for different selection functions in distinct areas of the sky. We present the full list of Abell clusters used, together with their redshifts and supercluster memberships and including the isolated clusters. The SSCC contains about twice the number of superclusters than MSCC for δ < −17°, which we found to be due to (1) new superclusters formed by A-clusters in their cores and surrounded by S-clusters (50 per cent), (2) new superclusters formed by S-clusters only (40 per cent), (3) redistribution of member clusters by fragmentation of rich (multiplicity m > 15) superclusters (8 per cent), and (4) new superclusters formed by the connection of A-clusters through bridges of S-clusters (2 per cent). Power-law fits to the cumulative supercluster multiplicity function yield slopes of α = −2.0 and α = −1.9 for MSCC and SSCC, respectively. This power-law behaviour is in agreement with the findings for other observational samples of superclusters, but not with that of catalogues based on cosmological simulations.
Recently Tsallis cosmology has been presented as a novel proposal for alleviating both
H
0
and
σ
8
tensions. Hence a universe filled with matter and radiation as perfect fluids and considering the ...Tsallis entropy is confronted using recent cosmological measurements coming from cosmic chronometers, type Ia supernovae, hydrogen II galaxies, quasars, and baryon acoustic oscillations. Following a Bayesian Markov Chain Monte Carlo analysis and combining the samples, we constrain the main characteristic parameters
α
=
1
.
031
-
0.051
+
0.054
and
δ
=
1
.
005
-
0.001
+
0.001
where the uncertainties are
1
σ
confidence level. Additionally, we estimate the current deceleration parameter
q
0
=
-
0
.
530
-
0.017
+
0.018
, the deceleration-acceleration transition redshift
z
T
=
0
.
632
-
0.028
+
0.028
and the age of the universe
τ
U
=
12
.
637
-
0.066
+
0.067
Gyrs
which are in agreement with the standard cosmology (
Λ
CDM) within
1.5
σ
. Furthermore, we find that the dark energy equation of state is consistent with both phantom and quintessence behaviors within
1
σ
in the past and converging to
Λ
CDM in the future. Additionally, we find agreement values of
H
0
within
1
σ
with the SH0ES values when the CMB distance priors are added to the analysis, suggesting that
H
0
tension could be alleviated. Finally, Tsallis cosmology is preferred over
Λ
CDM by the combined data that motives further studies at the perturbation level.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ABSTRACT
We explore the effects of tidal interactions on star formation (SF) by analysing a sample of CALIFA survey galaxies. The sample consists of tidally and non-tidally perturbed galaxies whose ...star-forming regions are paired at the closest stellar mass surface densities, even between the same galaxy types. The regions are then compared, both on the resolved star-formation main sequence (SFMS) plane and in annular property profiles. Star-forming regions in tidally perturbed galaxies exhibit flatter SFMS slopes compared to star-forming regions in non-tidally perturbed galaxies. Despite the fact that the annular profiles show star-forming regions in tidally perturbed galaxies as being mostly older, their SF properties are never reduced against those of non-tidally perturbed galaxies. Star-forming regions in non-tidally perturbed galaxies are better candidates for SF suppression (quenching). The lowered SF with increasing stellar mass density in tidally perturbed galaxies may suggest a lower dependence of SF on stellar mass. Though the SFMS slopes, either flatter or steeper, are found independent of stellar mass density, the effect of global stellar mass cannot be ignored when distinguishing between galaxy types. Since a phenomenon or property other than local/global stellar mass may be taking part in the modulation of SF, the integrated SF properties are related to the tidal perturbation parameter. We find weak, but detectable, positive correlations for perturbed galaxies suggesting that tidal perturbations induced by close companions increase the gas accretion rates of these objects.
Abstract
NGC 7469 is a well-known luminous infrared galaxy, with a circumnuclear star formation ring (∼830 pc radius) surrounding a Seyfert 1 active galactic nucleus (AGN). Nuclear unresolved winds ...were previously detected in X-rays and ultraviolet, as well as an extended biconical outflow in infrared coronal lines. We search for extended outflows by measuring the kinematics of the H
β
and O
iii
λ
5007 optical emission lines, in data of the Very Large Telescope/Multi-unit Spectroscopic Explorer integral field spectrograph. We find evidence of two outflow kinematic regimes: one slower regime extending across most of the star formation (SF) ring—possibly driven by the massive SF—and a faster regime (with a maximum velocity of −715 km s
−1
), only observed in O
iii
, in the western region between the AGN and the massive star-forming regions of the ring, likely AGN-driven. This work shows a case where combined AGN/SF feedback can be effectively spatially resolved, opening up a promising path toward a deeper understanding of feedback processes in the central kiloparsec of AGN.
ABSTRACT
Galaxy evolution is generally affected by tidal interactions. First, in this series, we reported several effects that suggest that tidal interactions contribute to the regulation of star ...formation (SF). To confirm this, we now compare stellar mass assembly histories and SF look-back time annular profiles between CALIFA survey tidally and non-tidally perturbed galaxies. We pair their respective star-forming regions at the closest stellar mass surface densities to reduce the influence of stellar mass. The assembly histories and annular profiles show statistically significant differences so that higher star-formation rates characterize regions in tidally perturbed galaxies. These regions underwent a more intense (re)activation of SF in the last 1 Gyr. Varying shapes of the annular profiles also reflect fluctuations between suppression and (re)activation of SF. Since gas-phase abundances used to be lower in more actively than in less actively star-forming galaxies, we further explore the plausible presence of metal-poor gas inflows able to dilute such abundances. The resolved relations of oxygen (O) abundance with stellar mass density and with total gas fraction show slightly lower O abundances for regions in tidally perturbed galaxies. The single distributions of O abundances statistically validate this. Moreover, from a metallicity model based on stellar feedback, the mass rate differentials (inflows−outflows) show statistically valid higher values for regions in tidally perturbed galaxies. These differentials, and the metal fractions from the population synthesis, suggest dominant gas inflows in these galaxies. This dominance and the differences in SF through time confirm the previously reported effects of tidal interactions on SF.
The optical spectra of 3896 Seyfert 1 (Sy1) galaxies detected with WISE at z < 0.4 were analyzed for evidence of outflows. In 37% of the Sy1s in our sample, the outflows appear as broad, ...blue-shifted, spectrally resolved components of the O iiiλ5007 emission line, with a mean maximum velocity Vmax ∼ 1014 km s−1 that is consistent with AGN winds. For each Sy1, we deduced the black hole (BH) mass, bolometric luminosity, Eddington ratio, and power-law index of the continuum, which we compared with the star formation rate (SFR) and host morphology. Having separated our sample in two spectroscopic subgroups-Sy1s with only broad Balmer lines (Sy1B) and those with both narrow and broad (Sy1N) lines-and distinguishing those that show as outflow (Sy1Bw and Sy1Nw), we report the following differences: (1) the BH mass is systematically higher and the power-law steeper in the Sy1B-Sy1Bw than in the Sy1N-Sy1Nw; (2) Vmax is higher in the Sy1Bw than in the Sy1Nw, correlated in both groups with the BH mass and bolometric luminosity; (3) the Eddington ratio and SFR are higher in the Sy1 with outflows; and (4) the specific star formation rates (sSFRs) of the Sy1s are normal for their morphology and mass, typical of early-type spiral galaxies in the green valley, far from the quenched regime. From these results, we conclude that AGN winds in Sy1s are triggered by higher accretion rates and probably radiatively launched, and there is no clear evidence of an effect on the star formation.
Background
Polyamines are involved in several cellular processes and inhibiting their synthesis affects chikungunya virus (CHIKV) replication and translation, and, therefore, reduces the quantity of ...infectious viral particles produced. In this study, we evaluated the inhibition of CHIKV replication by N-ω-chloroacetyl-L-ornithine (NCAO), a competitive inhibitor of ornithine decarboxylase, an enzyme which is key in the biosynthesis of polyamines (PAs).
Methods
The cytotoxicity of NCAO was evaluated by MTT in cell culture. The inhibitory effect of CHIKV replication by NCAO was evaluated in Vero and C6/36 cells. The intracellular polyamines were quantified by HPLC in CHIKV-infected cells. We evaluated the yield of CHIKV in titres via the addition of PAs in Vero, C6/36 cells and human fibroblast BJ treated with NCAO.
Results
We found that NCAO inhibits the replication of CHIKV in Vero and C6/36 cells in a dose-dependent manner, causing a decrease in the PFU/mL of at least 4 logarithms (p < 0.01) in both cell lines. Viral yields were restored by the addition of exogenous polyamines, mainly putrescine. The HPLC analyses showed that NCAO decreases the content of intracellular PAs, even though it is predominantly spermidines and spermines which are present in infected cells. Inhibition of CHIKV replication was observed in human fibroblast BJ treated with 100 μM NCAO 24 h before and 48 h after the infection at a MOI 1.
Conclusions
NCAO inhibits CHIKV replication by depleting the intracellular polyamines in Vero, C6/36 cells and human fibroblast BJ, suggesting that this compound is a possible antiviral agent for CHIKV.
Red sequence of Abell X-ray underluminous clusters Trejo-Alonso, J. J; Caretta, C. A; Laganá, T. F ...
Monthly notices of the Royal Astronomical Society,
06/2014, Letnik:
441, Številka:
1
Journal Article
Recenzirano
We present an analysis of the colour–magnitude relation for a sample of 56 Abell X-ray underluminous clusters. Our aim is to unveil properties that might elucidate the evolutionary stages of the ...galaxy populations that compose such systems. To do so, we have compared the parameters of their colour–magnitude relations with the ones found for another sample of 50 normal Abell X-ray emitting clusters, both samples selected in an objective way. The g and r magnitudes from Data Release 7 of the Sloan Digital Sky Survey were used for constructing the colour–magnitude relations. We have found that both samples show the same trend: the red-sequence slopes change with redshift, but the slopes for X-ray underluminous clusters are always flatter than those for normal clusters, with a difference of about 69 per cent along the surveyed redshift range of 0.05 ≤ z < 0.20. Also, the intrinsic scatter of the colour–magnitude relation was found to grow with redshift for both samples; however, for the X-ray underluminous clusters, this is systematically larger by about 28 per cent. By applying the Cramér test to the result of this comparison between X-ray normal and underluminous cluster samples, we obtain probabilities of 92 and 99 per cent that the red-sequence slope and intrinsic scatter distributions, respectively, differ, in the sense that X-ray underluminous clusters red sequences show flatter slopes and higher scatters in their relations. No significant differences in the distributions of red-sequence median colours are found between the two cluster samples. This points to X-ray underluminous clusters being younger systems than normal clusters, possibly in the process of accreting groups of galaxies, individual galaxies and gas.
Galaxy evolution is generally affected by tidal interactions. First, in this series, we reported several effects that suggest that tidal interactions contribute to the regulation of star formation ...(SF). To confirm this, we now compare stellar mass assembly histories and SF look-back time annular profiles between CALIFA survey tidally and non-tidally perturbed galaxies. We pair their respective star-forming regions at the closest stellar mass surface densities to reduce the influence of stellar mass. The assembly histories and annular profiles show statistically significant differences so that higher star-formation rates characterize regions in tidally perturbed galaxies. These regions underwent a more intense (re)activation of SF in the last 1 Gyr. Varying shapes of the annular profiles also reflect fluctuations between suppression and (re)activation of SF. Since gas-phase abundances used to be lower in more actively than in less actively star-forming galaxies, we further explore the plausible presence of metal-poor gas inflows able to dilute such abundances. The resolved relations of oxygen (O) abundance with stellar mass density and with total gas fraction show slightly lower O abundances for regions in tidally perturbed galaxies. The single distributions of O abundances statistically validate this. Moreover, from a metallicity model based on stellar feedback, the mass rate differentials (inflows-outflows) show statistically valid higher values for regions in tidally perturbed galaxies. These differentials, and the metal fractions from the population synthesis, suggest dominant gas inflows in these galaxies. This dominance and the differences in SF through time confirm the previously reported effects of tidal interactions on SF.
HIV infection has become a chronic disease and well-being of people living with HIV (PLHIV) is now of particular concern. The objectives of this paper were to describe self-rated health among PLHIV, ...on ART and on ART virally suppressed and to analyse its determinants.
Data were obtained from a second-generation surveillance system based on a cross-sectional one-day survey in public hospitals. Epidemiological and clinical data were collected among HIV-infected inpatients and outpatients receiving HIV-related care the day of the survey in 86 hospitals in 2019. Self-rated health was measured using a question included in the National Health Survey: "In the last 12 months, how would you rate your health status?" an ordinal variable with five categories (very good, good, moderate, bad and very bad). For the analysis, these responses were dichotomized into two categories: 1 = very good/good and 0 = moderate, bad or very bad health status. Factors associated with very good/good self-rated health were estimated using logistic regression.
Of 800 PLHIV, 67.5% perceived their health as very good/good, 68.4% among PLHIV on ART and 71.7% of those virally suppressed. Having university education (adjusted odds ratio (aOR):2.1), being unemployed (aOR:0.3) or retired (aOR:0.2), ever being diagnosed of AIDS (aOR:0.6), comorbidities (aOR:0.3), less than 2 year since HIV diagnosis (aOR:0.3) and not receiving ART (aOR:0.3) were associated with good self-rated health. Moreover, among PLHIV on ART, viral load less than 200 copies (aOR:3.2) were related to better perceived health. Bad adherence was inversely associated with good self-rated health among PLHIV on ART (aOR:0.5) and of those virally suppressed (aOR:0.4).
Nearly seven in 10 PLHIV in Spain considered their health status as very good/good, being higher among virally suppressed PLHIV. Both demographic and clinical determinants affect quality of life.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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