32 research outputs found

    Electrophysiological Parameters of Sinus Node Function in Patients with Paroxysmal Tachyarrhythmias

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    to analyze the indicators of the function of the sinus node in patients of young age with paroxysmal tachycardia. Methods: study included 11 patients with suspected paroxysmal tachycardia, with an average age of 17±28. The basis for holding transesophageal electrophysiological study (TE EPS) was the clinical and electrophysiological characteristics of paroxysmal tachycardia. According to the results of Holter monitoring ECG (HM ECG) analyzed the minimum and maximum heart rate, number of ventricular and supraventricular arrhythmias, presence of pauses, rhythm and episodes of paroxysmal tachycardia. According to CHP, EFI estimated the initial heart rate (HR), recovery time of sinus node function (RTSNF), corrected recovery time of sinus node function (CRTSNF), point of Wenkebach (p. W), duration of the effective refractory period of the atrioventricular connections, presence of aberrant complexes and episodes of paroxysmal tachycardias before and after administration of atropine at a dose of 0.02 mg/kg. Results: Complaints characteristic of the tachyarrhythmia was diagnosed in 9 patients, episodes of heart rate more than 150 beats per minute in 7 patients. When conducting TE EPS obtained the following results: episodes of supraventricular tachycardia provoked in 8 patients (in two cases of paroxysmal tachycardia managed to provoke only after administration of atropine). Three of them have shimmer and atrial flutter episodes reciprocal tachycardia in five. Three patients provoke paroxysmal tachycardia failed, but they showed a shortening of the PQ interval and the appearance of aberrant QRS complexes when stimulated. In patients with paroxysmal SVT signs of sinus node dysfunction was detected in 6 patients, in the form of episodes of sinus arrhythmia (4 patients), migration pacemaker the atria (4 patients), sinoatrial blockade of II degree (3 patients), blockade of legs of bunch of gisa (2 patients), atrioventricular block degree II-III (1 patient), RTSNF more than 1500 MS in 1 patient, CRTSNF greater than 500 msec in 3 patients. Conclusion: in 6 of 9 patients with supraventricular paroxysmal tachycardia revealed signs of sinus node dysfunction, probably has a vagotonic in nature

    The effect of active galactic nuclei on the cold interstellar medium in distant star-forming galaxies

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    In the framework of a systematic study with the ALMA interferometer of IR-selected main-sequence and starburst galaxies at z ∌ 1 − 1.7 at typical ∌1″ resolution, we report on the effects of mid-IR- and X-ray-detected active galactic nuclei (AGN) on the reservoirs and excitation of molecular gas in a sample of 55 objects. We find widespread detectable nuclear activity in ∌30% of the sample. The presence of dusty tori influences the IR spectral energy distribution of galaxies, as highlighted by the strong correlation among the AGN contribution to the total IR luminosity budget (fAGN = LIR,  AGN/LIR), its hard X-ray emission, and the Rayleigh-Jeans to mid-IR (S1.2 mm/S24 Όm) observed color, with evident consequences on the ensuing empirical star formation rate estimates. Nevertheless, we find only marginal effects of the presence and strength of AGN on the carbon monoxide CO (J = 2, 4, 5, 7) or neutral carbon ([C I](3P1  −  3P0), [C I](3P2  −  3P1)) line luminosities and on the derived molecular gas excitation as gauged by line ratios and the full spectral line energy distributions. The [C I] and CO emission up to J = 5, 7 thus primarily traces the properties of the host in typical IR luminous galaxies. However, our analysis highlights the existence of a large variety of line luminosities and ratios despite the homogeneous selection. In particular, we find a sparse group of AGN-dominated sources with the highest LIR,  AGN/LIR,  SFR ratios, ≳3, that are more luminous in CO (5−4) than what is predicted by the Lâ€ČCO(5-4)−LIR, SFR relation, which might be the result of the nuclear activity. For the general population, our findings translate into AGN having minimal effects on quantities such as gas and dust fractions and star formation efficiencies. If anything, we find hints of a marginal tendency of AGN hosts to be compact at far-IR wavelengths and to display 1.8 times larger dust optical depths. In general, this is consistent with a marginal impact of the nuclear activity on the gas reservoirs and star formation in average star-forming AGN hosts with LIR > 5 × 1011 L⊙, typically underrepresented in surveys of quasars and submillimeter galaxies

    CO emission in distant galaxies on and above the main sequence

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    We present the detection of multiple carbon monoxide CO line transitions with ALMA in a few tens of infrared-selected galaxies on and above the main sequence at z = 1.1−1.7. We reliably detected the emission of CO (5−4), CO (2−1), and CO (7−6)+[C I](3P2 − 3P1) in 50, 33, and 13 galaxies, respectively, and we complemented this information with available CO (4 − 3) and [C I](3P1 − 3P0) fluxes for part of the sample, and by modeling of the optical-to-millimeter spectral energy distribution. We retrieve a quasi-linear relation between LIR and CO (5 − 4) or CO (7 − 6) for main-sequence galaxies and starbursts, corroborating the hypothesis that these transitions can be used as star formation rate (SFR) tracers. We find the CO excitation to steadily increase as a function of the star formation efficiency, the mean intensity of the radiation field warming the dust (hUi), the surface density of SFR (ÎŁSFR), and, less distinctly, with the distance from the main sequence (∆MS). This adds to the tentative evidence for higher excitation of the CO+[C I] spectral line energy distribution (SLED) of starburst galaxies relative to that for main-sequence objects, where the dust opacities play a minor role in shaping the high-J CO transitions in our sample. However, the distinction between the average SLED of upper main-sequence and starburst galaxies is blurred, driven by a wide variety of intrinsic shapes. Large velocity gradient radiative transfer modeling demonstrates the existence of a highly excited component that elevates the CO SLED of high-redshift main-sequence and starbursting galaxies above the typical values observed in the disk of the Milky Way. This excited component is dense and it encloses ∌50% of the total molecular gas mass in main-sequence objects. We interpret the observed trends involving the CO excitation as to be mainly determined by a combination of large SFRs and compact sizes, as a large ÎŁSFR is naturally connected with enhanced dense molecular gas fractions and higher dust and gas temperatures, due to increasing ultraviolet radiation fields, cosmic ray rates, as well as dust and gas coupling. We release the full data compilation and the ancillary information to the community

    ALMA Lensing Cluster Survey: HSTHST and SpitzerSpitzer Photometry of 33 Lensed Fields Built with CHArGE

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    We present a set of multi-wavelength mosaics and photometric catalogs in the ALMA lensing cluster survey (ALCS) fields. The catalogs were built by reprocessing of archival data from the CHArGE compilation, taken by the Hubble Space Telescope\textit{Hubble Space Telescope} (HST\textit{HST}) in the RELICS, CLASH and Hubble Frontier Fields. Additionally we have reconstructed the Spitzer\textit{Spitzer} IRAC 3.6 and 4.5 Ό\mum mosaics, by utilising all the available archival IRSA/SHA exposures. To alleviate the effect of blending in such a crowded region, we have modelled the Spitzer\textit{Spitzer} photometry by convolving the HST\textit{HST} detection image with the Spitzer\textit{Spitzer} PSF using the novel golfir\texttt{golfir} software. The final catalogs contain 218,000 sources, covering a combined area of 690 arcmin2^2. These catalogs will serve as an important tool in aiding the search of the sub-mm galaxies in future ALMA surveys, as well as follow ups of the HST\textit{HST} dark - IRAC sources. Coupled with the available HST\textit{HST} photometry the addition of the 3.6 and 4.5 Ό\mum bands will allow us to place a better constraint on photometric redshifts and stellar masses of these objects, thus giving us an opportunity to identify high-redshift candidates for spectroscopic follow ups and answer the important questions regarding the epoch of reionization and formation of first galaxies.Comment: 35 pages, 19 figures, 4 tables. Submitted to ApJS. Mosaics and photometric catalogs can be accessed online https://github.com/dawn-cph/alcs-cluster

    Unbiased surveys of dust-enshrouded galaxies using ALMA

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    The ALMA lensing cluster survey (ALCS) is a 96-hr large program dedicated to uncovering and characterizing intrinsically faint continuum sources and line emitters with the assistance of gravitational lensing. All 33 cluster fields were selected from HST/Spitzer treasury programs including CLASH, Hubble Frontier Fields, and RELICS, which also have Herschel and Chandra coverages. The total sky area surveyed reaches ∌\sim133 arcmin2^2 down to a depth of ∌\sim60 ÎŒ\muJy beam−1^{-1} (1σ\sigma) at 1.2 mm, yielding 141 secure blind detections of continuum sources and additional 39 sources aided by priors. We present scientific motivation, survey design, the status of spectroscopy follow-up observations, and number counts down to ∌\sim7 ÎŒ\muJy. Synergies with JWST are also discussed.Comment: 6 pages, 4 figures, Proceedings of the 7th Chile-Cologne-Bonn-Symposium: Physics and Chemistry of Star Formation, V. Ossenkopf-Okada, R. Schaaf, I. Breloy (eds.

    COSMOS2020: The Galaxy Stellar Mass Function: the assembly and star formation cessation of galaxies at 0.2<z≀7.50.2\lt z \leq 7.5

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    How galaxies form, assemble, and cease their star-formation is a central question within the modern landscape of galaxy evolution studies. These processes are indelibly imprinted on the galaxy stellar mass function (SMF). We present constraints on the shape and evolution of the SMF, the quiescent galaxy fraction, and the cosmic stellar mass density across 90% of the history of the Universe from z=7.5→0.2z=7.5\rightarrow0.2 via the COSMOS survey. Now with deeper and more homogeneous near-infrared coverage exploited by the COSMOS2020 catalog, we leverage the large 1.27 deg2^{2} effective area to improve sample statistics and understand cosmic variance particularly for rare, massive galaxies and push to higher redshifts with greater confidence and mass completeness than previous studies. We divide the total stellar mass function into star-forming and quiescent sub-samples through NUVrJNUVrJ color-color selection. Measurements are then fitted with Schechter functions to infer the intrinsic SMF, the evolution of its key parameters, and the cosmic stellar mass density out to z=7.5z=7.5. We find a smooth, monotonic evolution in the galaxy SMF since z=7.5z=7.5, in agreement with previous studies. The number density of star-forming systems seems to have undergone remarkably consistent growth spanning four decades in stellar mass from z=7.5→2z=7.5\rightarrow2 whereupon high-mass systems become predominantly quiescent (i.e. downsizing). An excess of massive systems at z∌2.5−5.5z\sim2.5-5.5 with strikingly red colors, some newly identified, increase the observed number densities to the point where the SMF cannot be reconciled with a Schechter function. Systematics including cosmic variance and/or AGN contamination are unlikely to fully explain this excess, and so we speculate that there may be contributions from dust-obscured objects similar to those found in FIR surveys. (abridged)Comment: 39 pages, 24 figures, accepted for publication in A&A. Data files containing key measurements are available for download: https://doi.org/10.5281/zenodo.780883

    UNCOVER: A NIRSpec Identification of a Broad-line AGN at z = 8.50

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    Deep observations with the James Webb Space Telescope (JWST) have revealed an emerging population of red pointlike sources that could provide a link between the postulated supermassive black hole seeds and observed quasars. In this work, we present a JWST/NIRSpec spectrum from the JWST Cycle 1 UNCOVER Treasury survey of a massive accreting black hole at z = 8.50 displaying a clear broad-line component as inferred from the HÎČ line with FWHM = 3439 ± 413 km s−1, typical of the broad-line region of an active galactic nucleus (AGN). The AGN nature of this object is further supported by high ionization, as inferred from emission lines, and a point-source morphology. We compute a black hole mass of log 10 ( M BH / M ⊙ ) = 8.17 ± 0.42 and a bolometric luminosity of L bol ∌ 6.6 × 1045 erg s−1. These values imply that our object is accreting at ∌40% of the Eddington limit. Detailed modeling of the spectral energy distribution in the optical and near-infrared, together with constraints from ALMA, indicate an upper limit on the stellar mass of log 10 ( M * / M ⊙ ) < 8.7 , which would lead to an unprecedented ratio of black hole to host mass of at least ∌30%. This is orders of magnitude higher compared to the local QSOs but consistent with recent AGN studies at high redshift with JWST. This finding suggests that a nonnegligible fraction of supermassive black holes either started out from massive seeds and/or grew at a super-Eddington rate at high redshift. Given the predicted number densities of high-z faint AGN, future NIRSpec observations of larger samples will allow us to further investigate galaxy-black hole coevolution in the early Universe
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