Formation of S0 galaxies through mergers Querejeta, M.; Eliche-Moral, M. C.; Tapia, T. ...
Astronomy and astrophysics (Berlin),
07/2015, Letnik:
579
Journal Article
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The CALIFA team has recently found that the stellar angular momentum and concentration of late-type spiral galaxies are incompatible with those of lenticular galaxies (S0s), concluding that fading ...alone cannot satisfactorily explain the evolution from spirals into S0s. Here we explore whether major mergers can provide an alternative way to transform spirals into S0s by analysing the spiral-spiral major mergers from the GalMer database that lead to realistic, relaxed S0-like galaxies. We find that the change in stellar angular momentum and concentration can explain the differences in the λRe–R90/R50 plane found by the CALIFA team. Major mergers thus offer a feasible explanation for the transformation of spirals into S0s.
We present clinical and cytogenetic studies of a female patient affected with choroideremia, mild sensorineural deafness, and primary amenorrhea showing a balanced translocation between chromosomes X ...and 4. The breakpoint was precisely defined applying FISH techniques: 46,X,t(X; 4)(q21.2; p16.3).ish t(X; 4)(D4S96+, D4F26+; wcpX+). The X-chromosomal breakpoint was located within a region where both the choroideremia locus and a deafness locus (DFN3/POU3F4) have been mapped. The presence of X-linked disorders in this balanced carrier of X-autosomal translocations (XAT) can be explained either by the disruption of the structural coding or regulatory sequences of the gene(s) or by the submicroscopic deletion of this region leading to a contiguous gene deletion syndrome. The primary ovarian failure (POF) found in the present case has been already observed in XAT when the breakpoint is within a previously defined critical region (Xq13-26). A position effect is postulated as a possible explanation.
Identification of a Potential Cardiac Antifibrotic Mechanism of Torasemide in Patients With Chronic Heart Failure Begoña López, Arantxa González, Javier Beaumont, Ramón Querejeta, Mariano Larman, ...Javier Díez We investigated whether torasemide inhibits procollagen type I carboxy-terminal protease (PCP), the enzyme responsible for the extracellular generation of collagen type I, in patients with chronic heart failure. The PCP activation diminished in torasemide-treated but not in furosemide-treated patients. The PCP inhibition was associated with reduction of myocardial collagen in torasemide-treated patients. These findings suggest that the ability of torasemide to decrease myocardial fibrosis in heart failure is related to the inhibition of myocardial PCP.
Circulating Biomarkers of Myocardial Fibrosis López, Begoña, PhD; González, Arantxa, PhD; Ravassa, Susana, PhD ...
Journal of the American College of Cardiology,
06/2015, Letnik:
65, Številka:
22
Journal Article
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Abstract Myocardial fibrosis impairs cardiac function, in addition to facilitating arrhythmias and ischemia, and thus influences the evolution and outcome of cardiac diseases. Its assessment is ...therefore clinically relevant. Although tissue biopsy is the gold standard for the diagnosis of myocardial fibrosis, a number of circulating biomarkers have been proposed for the noninvasive assessment of this lesion. A review of the published clinical data available on these biomarkers shows that most of them lack proof that they actually reflect the myocardial accumulation of fibrous tissue. In this “call to action” article, we propose that this absence of proof may lead to misinterpretations when considering the incremental value provided by the biomarkers with respect to traditional diagnostic tools in the clinical handling of patients. We thus argue that strategies are needed to more strictly validate whether a given circulating biomarker actually reflects histologically proven myocardial fibrosis before it is applied clinically.
We analyse the influence of the dynamical environment on the star formation (SF) relations of the dense molecular gas in the starburst (SB) ring of the Seyfert 2 galaxy NGC 1068. We used ALMA to ...image the emission of the 1-0 transitions of HCN and HCO+ with a resolution of 56 pc. We also used ancillary data of CO(1-0) at a resolution of ~100 pc, and CO(3-2) and its underlying continuum emission at ~40 pc. These observations allow us to probe a range of molecular gas densities (n(H2)~10\(^{3-5}cm^{-3}\)). The SF rate (SFR) is derived from Pa\(\alpha\) line emission imaged by HST/NICMOS. We analysed how SF relations change depending on the choice of aperture sizes and molecular gas tracer. The scatter in the Kennicutt-Schmidt relation is about a factor of two to three lower for the HCN and HCO+ lines compared to CO(1-0) for a common aperture. Correlations lose statistical significance below a critical spatial scale \(\approx\)300-400 pc. The SF efficiency of the dense molecular gas (SFEdense) shows a scattered distribution as a function of the HCN luminosity (L'(HCN)) around a mean value of \(\simeq0.01\)Myr\(^{-1}\). An alternative prescription for SF relations, linking the SFEdense and the boundedness of the gas measured by the parameter b\(\equiv\Sigma\)dense/\(\sigma^2\), where \(\Sigma\)dense is the dense molecular gas surface density and \(\sigma\) the velocity dispersion, resolves the degeneracy associated with the SFEdense-L'(HCN) plot. We identify two branches in the SFEdense-b plot that correspond to two dynamical environments in the SB ring, which are defined by their proximity to the bar-ring interface region. This region corresponds to the crossing of two density wave resonances, where an increased rate of cloud-cloud collisions would favour an enhanced compression of molecular gas. Our results suggest that galactic dynamics plays a major role in the efficiency of the gas conversion into stars.
A&A 676, L11 (2023) Nitrogen hydrides such as NH$_3$ and N$_2$H$^+$ are widely used by Galactic
observers to trace the cold dense regions of the interstellar medium. In
external galaxies, because of ...limited sensitivity, HCN has become the most
common tracer of dense gas over large parts of galaxies. We provide the first
systematic measurements of N$_2$H$^+$(1-0) across different environments of an
external spiral galaxy, NGC6946. We find a strong correlation ($r>0.98,p<0.01$)
between the HCN(1-0) and N$_2$H$^+$(1-0) intensities across the inner
$\sim8\mathrm{kpc}$ of the galaxy, at kiloparsec scales. This correlation is
equally strong between the ratios N$_2$H$^+$(1-0)/CO(1-0) and HCN(1-0)/CO(1-0),
tracers of dense gas fractions ($f_\mathrm{dense}$). We measure an average
intensity ratio of N$_2$H$^+$(1-0)/HCN(1-0)$=0.15\pm0.02$ over our set of five
IRAM-30m pointings. These trends are further supported by existing measurements
for Galactic and extragalactic sources. This narrow distribution in the average
ratio suggests that the observed systematic trends found in kiloparsec-scale
extragalactic studies of $f_\mathrm{dense}$ and the efficiency of dense gas
(SFE$_\mathrm{dense}$) would not change if we employed N$_2$H$^+$(1-0) as a
more direct tracer of dense gas. At kiloparsec scales our results indicate that
the HCN(1-0) emission can be used to predict the expected N$_2$H$^+$(1-0) over
those regions. Our results suggest that, even if HCN(1-0) and N$_2$H$^+$(1-0)
trace different density regimes within molecular clouds, subcloud differences
average out at kiloparsec scales, yielding the two tracers proportional to each
other.
We use a sample of 64 nearby (D=7-45 Mpc) disk galaxies including 45 AGN and 19 non-AGN, that have high spatial resolution multiline CO observations obtained with the ALMA and/or PdBI arrays to study ...the distribution of cold molecular gas in their circumunuclear disks (CND). We analyze whether the concentration of cold molecular gas changes as a function of the X-ray luminosity in the 2-10 keV range (\(L_{\rm X}\)). We also study the concentration of the hot molecular gas using NIR data obtained for the H2 1-0S(1) line. We find a turnover in the distribution of the cold molecular gas concentration as a function of \(L_{\rm X}\) with a breakpoint which divides the sample into two branches: the AGN build-up branch (\(L_{\rm X}\leq10^{41.5\pm0.3}\)erg/s) and the AGN feedback branch (\(L_{\rm X}\geq10^{41.5\pm0.3}\)erg/s) . Lower luminosity AGN and non-AGN of the AGN build-up branch show high cold molecular gas concentrations and centrally peaked radial profiles on nuclear (\(r\leq50\)~pc) scales. Higher luminosity AGN of the AGN feedback branch, show a sharp decrease in the concentration of molecular gas and flat or inverted radial profiles. The cold molecular gas concentration index (\(CCI\)), defined as the ratio of surface densities at \(r\leq50\)~pc and \(r\leq200\)~pc , namely \(CCI \equiv\)~log\(_{\rm 10}(\Sigma^{\rm gas}_{\rm 50}/\Sigma^{\rm gas}_{\rm 200}\)), spans a factor ~4-5 between the galaxies lying at the high end of the AGN build-up branch and the galaxies of the AGN feedback branch. The concentration and radial distributions of the hot molecular gas in our sample follow less extreme trends as a function of the X-ray luminosity. These observations confirm, on a three times larger sample, previous evidence found by the GATOS survey that the imprint of AGN feedback on the CND-scale distribution of molecular gas is more extreme in higher luminosity Seyfert galaxies of the local universe.
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