NGC 2770: high supernova rate due to interaction

Galaxies which hosted many core-collapse supernovae (SN) explosions can be used to study the conditions necessary for the formation of massive stars. NGC 2770 was dubbed a SN factory, because it hosted four core-collapse SNe in 20 years (three type Ib and one type IIn). Its star formation rate (SFR) was reported not to be enhanced and therefore not compatible with such a high SN rate. We aim at explaining the high SN rate of NGC 2770. We used archival HI line data for NGC 2770 and reinterpret the Halpha and optical continuum data. Even though the continuum-based SFR indicators do not yield high values, the dust-corrected Halpha luminosity implies a high SFR, consistent with the high SN rate. Such disparity between the SFR estimators is an indication of recently enhanced star formation activity, because the continuum indicators trace long timescale of the order of 100 Myr, unlike the line indicators, which trace timescales of the order of 10 Myr. Hence, the unique feature of NGC 2770 compared to other galaxies is the fact that it is observed very recently after the enhancement of the SFR. It also has high dust extinction, E(B-V) above 1 mag. We provide support for the hypothesis that the increased SFR in NGC 2770 is due to the interaction with its companion galaxies. We report an HI bridge between NGC 2770 and its closest companion and the existence of a total of four companions within 100 kpc (one identified for the first time). There are no clear HI concentrations close to the positions of SNe in NGC 2770 such as those detected for hosts of gamma-ray bursts (GRBs) and broad-lined SNe type Ic (IcBL). This suggests that the progenitors of type Ib SNe are not born out of recently accreted atomic gas, as was suggested for GRB and IcBL SN progenitors.Comment: Astronomy & Astrophysics, in press, 8 pages, 3 figures, 1 tabl

За кадры. 1971. № 61 (1575)

Рядовые студенческой гвардии / М. БорисоваКонференции в Оксфорде / С. П. БугаевДонести до каждого / А. АлександровичБольше доверия! / Г. КуницынВ звании студента утвержден / П. СеменовПоложение о проведении в комсомольской организации ТПИ Ленинского зачета "Решения XXIV съезда КПСС - в жизнь"Осенние мелодии / А. МеркушеваПриглашает оперная студияВ братской Монголии / И. Т. Лозовски

Clinical profile of a Polish cohort of children and young adults with cystinuria

Background Cystinuria is an inherited disorder that results in increased excretion of cystine in the urine. It accounts for about 1-2% of pediatric kidney stones. In this study, we sought to identify the clinical characteristics of patients with cystinuria in a national cohort. Methods This was a retrospective study involving 30 patients from the Polish Registry of Inherited Tubulopathies. Initial data and that from a 6-month follow-up were analyzed. Mutational analysis was performed by targeted Sanger sequencing and, if applicable, MLPA analysis was used to detect large rearrangements. Results SLC7A9 mutations were detected in 15 children (50%; 10 males, 5 females), SLC3A1 mutations in 14 children (47%; 5 males, 9 females), and bigenic mutations in one male patient. The first clinical symptoms of the disease were detected at a median of 48 months of age (range 3-233 months). When individuals with different mutations were compared, there were no differences identified in gender, age of diagnosis, presence of UTI or urolithiasis, eGFR, calcium, or cystine excretion. The most common initial symptoms were urolithiasis in 26 patients (88%) and urinary tract infections in 4 patients (13%). Urological procedures were performed in 18 out of 30 (60%). Conclusions The clinical course of cystinuria is similar among patients, regardless of the type of genetic mutation. Most patients require surgery before diagnosis or soon after it. Patients require combined urological and pharmacological treatment for prevention of stone recurrence and renal function preservation