ISM enrichment and local pollution in dwarf galaxies

The fate of metals after they are released in starburst episodes is still unclear. What phases of the interstellar medium are involved, in which timescales? Evidence has grown over the past few years that the neutral phase of blue compact dwarf (BCD) galaxies may be metal- deficient as compared to the ionized gas of their HII regions. These results have strong implications for our understanding of the chemical evolution of galaxies. We review here the main results and the main caveats in the abundance determination from far-UV absorption-lines. We also discuss possible scenarios concerning the journey of metals into the interstellar medium, or even their ejection from the galaxy into the intergalactic medium.Comment: Long version of a proceeding for the conference "A Universe of Dwarf Galaxies: Observations, Theories, Simulations" held in Lyon, France (14th-18th, June 2010

Conservation and Reassessment of an Overlooked Skeletal Collection Preserved Since 1901 at the Museum of Anthropology “G. Sergi”, Rome

The osteological investigation of archived and historic skeletal collections can often provide clues to how they were organised and managed, offering key osteobiographical insight into past populations. A small, yet significant, collection of skulls housed at the Museum “Giuseppe Sergi” of the Sapienza University of Rome, remained anonymous prior to a recent reassessment protocol started in 2018. This collection was excavated from a funerary area discovered during the 19th century from the site of Castel Trosino (Ascoli Piceno, Italy). The cemetery was part of an important community during the Longobard domination of Italy, as testified by the richness of the cultural artefacts reported with the burials. The 19 skulls presented in this paper are the only ones available for assessment; all the others were lost shortly after the first excavation. Their importance is related to providing a better understanding of biological evidence of a community that lived in Italy during the Early Middle Ages.Attraverso la chiave di lettura osteobiografica, l'indagine di collezioni scheletriche storiche custodite presso Musei e Soprintendenze può fornire nuovi indizi per la loro storia degli studi. Una piccola ma significativa collezione di crani, ospitata presso il Museo "Giuseppe Sergi" della Sapienza Università di Roma, è rimasta anonima fino ad un recente protocollo di indagine iniziato nel 2018. Questa collezione fu recuperata dall'area funeraria scoperta nel corso del XIX secolo nel sito di Castel Trosino (Ascoli Piceno, Italia). Questo cimitero faceva parte di un’importante comunità durante il periodo della dominazione longobarda d'Italia, come testimoniato dalla ricchezza dei corredi recuperati. I 19 crani presentati in questo lavoro sono gli unici disponibili per lo studio, tutti gli altri sono andati persi poco dopo il primo scavo. La loro importanza è legata alla ricerca di una maggiore comprensione delle testimonianze osteologiche della comunità altomedievale di Castel Trosino

Interstellar abundances in the neutral and ionized gas of NGC604

We present FUSE spectra of the giant HII region NGC604 in the spiral galaxy M33. Chemical abundances are derived from far-UV absorption lines and are compared to those derived from optical emission lines. We derived the column densities of HI, NI, OI, SiII, PII, ArI, and FeII, fitting the line profiles with either a single component or several components. Our net results, assuming a single component, show that N, O, Si, and Ar are apparently underabundant in the neutral phase by a factor of 10 or more with respect to the ionized phase, while Fe is the same. However, we discuss the possibility that the absorption lines are made of individual unresolved components, and find that only PII, ArI, and FeII lines should not be affected by the presence of hidden saturated components, while NI, OI, and SiII might be much more affected. If N, O, and Si are actually underabundant in the neutral gas of NGC604 with respect to the ionized gas, this would confirm earlier results obtained for the blue compact dwarfs. However, a deeper analysis focused on P, Ar, and Fe mitigates the above conclusion and indicates that the neutral gas and ionized gas could have similar abundances.Comment: Accepted for publication in A&

Patterns of FIRST recurrence of stage IIIC1 endometrial cancer with no PARAAORTIC nodal assessment.

OBJECTIVE: To assess the rates and distribution of first recurrence in patients with FIGO stage IIIC1 endometrial cancer (EC) who did not undergo paraaortic dissection at surgical staging. METHODS: We retrospectively selected all (n = 207) stage IIIC1 patients treated at a single institution from 5/1993-1/2017. Sites of first recurrence were identified, disease-free (DFS) and overall survival (OS) calculated, multivariate logistic regression performed to identify factors associated with recurrence. RESULTS: Three-year DFS and OS were 66.5% and 85.7%, respectively. The most common histology was endometroid (64.2%). Three-year DFS was 81% (SE±3.8%) endometrioid vs. 39.5% (SE±6.6%) non-endometrioid (P < 0.001). Three-year OS was 96.9% (SE±1.8%) endometrioid vs. 65.6% (SE±6.7%) non-endometrioid (P < 0.001). Sixty-two (30.1%) patients recurred. Patterns of recurrence were: 14 (8.3%) multiple sites, 17 (8.2%) abdominal, 14 (6.8%) extra-abdominal, 17 (8.3%) isolated nodal (8 of these (3.9%) paraaortic). Patients with isolated tumor cells (ITCs) in lymph nodes only had 12/71 (17%) recurrence rate vs. 50/135 (37%) for patients with micro-/macrometastasis. On univariate analysis, grade (HR 4.67 95%CI 1.5-14.5, P = 0.008), histology (HR 4.9 95%CI 2.6-9.3, P < 0.001), myometrial invasion (HR 1.9 95%CI 1.04-3.5, P = 0.04), pelvic washing (HR 2.2 95%CI 1.1-4.5, P = 0.03), tumor volume in pelvic LNs (ITC vs. micro-/macrometastasis; HR 0.3 95%CI 0.2-0.7, P = 0.003) were associated with recurrence. On multivariate analysis, only histology was associated with recurrence (HR 7.88 95%CI 3.43-18.13, P < 0.001). CONCLUSIONS: Isolated paraaortic recurrence in stage IIIC1 EC is uncommon. Micro-/macrometastasis were associated with twice the recurrence rate compared to ITC. These data will help clinicians counsel patients with stage IIIC1 EC regarding paraaortic assessment

Physical Properties of Young Stellar Populations in 24 Starburst Galaxies Observed with FUSE

We presents the main physical properties of very young stellar populations seen with FUSE in 24 individual starbursts. These characteristics have been obtained using the evolutionary spectral synthesis technique in the far-ultraviolet range with the LavalSB code. For each starburst, quantitative values for age, metallicity, initial mass function slope, stellar mass, and internal extinction have been obtained and discussed in details. Limits of the code have been tested. One main conclusion is that most starbursts (and probably all of them) cannot be represented by any continuous star formation burst in the far-ultraviolet. Also, quantitative values of various optical diagnostics related to these stellar populations have been predicted. Underlying stellar populations, dominated by B-type stars, have been detected in NGC 1140, NGC 4449, and possibly NGC 3991. We characterized the young stellar populations of less than 5 Myr in Seyfert 2 nuclei.Comment: 24 pages including figures. Accepted for publication in MNRA

Metal enrichment of the neutral gas of blue compact dwarf galaxies: the compelling case of Pox 36

We present the analysis of the interstellar spectrum of Pox 36 with the Far Ultraviolet Spectroscopic Explorer (FUSE). Pox 36 was selected because of the relatively low foreground gas content that makes it possible to detect absorption-lines weak enough that unseen components should not be saturated. Interstellar lines of HI, NI, OI, SiII, PII, ArI, and FeII are detected. Column densities are derived directly from the observed line profiles except for HI, whose lines are contaminated by stellar absorption. We used the TLUSTY models to remove the stellar continuum and isolate the interstellar component. The best fit indicates that the dominant stellar population is B0. The fit of the interstellar HI line gives a column density of 10^{20.3\pm0.4} cm-2. Chemical abundances were then computed from the column densities using the dominant ionization stage in the neutral gas. Our abundances are compared to those measured from emission-line spectra in the optical. Our results suggest that the neutral gas of Pox 36 is metal-deficient by a factor ~7 as compared to the ionized gas, and they agree with a metallicity of ~1/35 Z$_\odot$. Conclusions: The abundance discontinuity between the neutral and ionized phases implies that most of the metals released by consecutive star-formation episodes mixes with the HI gas. The volume extent of the enrichment is so large that the metallicity of the neutral gas increases only slightly. The star-forming regions could be enriched only by a small fraction (~1%), but it would greatly enhance its metallicity. Our results are compared to those of other BCDs. We confirm the overall underabundance of metals in their neutral gas, with perhaps only the lowest metallicity BCDs showing no discontinuity.Comment: Accepted for publication in A&

Synthetic High-Resolution Line Spectra of Star-Forming Galaxies Below 1200A

We have generated a set of far-ultraviolet stellar libraries using spectra of OB and Wolf-Rayet stars in the Galaxy and the Large and Small Magellanic Cloud. The spectra were collected with the Far Ultraviolet Spectroscopic Explorer and cover a wavelength range from 1003.1 to 1182.7A at a resolution of 0.127A. The libraries extend from the earliest O- to late-O and early-B stars for the Magellanic Cloud and Galactic libraries, respectively. Attention is paid to the complex blending of stellar and interstellar lines, which can be significant, especially in models using Galactic stars. The most severe contamination is due to molecular hydrogen. Using a simple model for the H$_2$ line strength, we were able to remove the molecular hydrogen lines in a subset of Magellanic Cloud stars. Variations of the photospheric and wind features of CIII 1176, OVI 1032, 1038, PV 1118, 1128, and SIV 1063, 1073, 1074 are discussed as a function of temperature and luminosity class. The spectral libraries were implemented into the LavalSB and Starburst99 packages and used to compute a standard set of synthetic spectra of star-forming galaxies. Representative spectra are presented for various initial mass functions and star formation histories. The valid parameter space is confined to the youngest ages of less than 10 Myr for an instantaneous burst, prior to the age when incompleteness of spectral types in the libraries sets in. For a continuous burst at solar metallicity, the parameter space is not limited. The suite of models is useful for interpreting the restframe far-ultraviolet in local and high-redshift galaxies.Comment: 33 pages including 13 figures, accepted for publication in Ap

Long-rising Type II Supernovae in the Zwicky Transient Facility Census of the Local Universe

SN 1987A was an unusual hydrogen-rich core-collapse supernova originating from a blue supergiant star. Similar blue supergiant explosions remain a small family of events, and are broadly characterized by their long rises to peak. The Zwicky Transient Facility (ZTF) Census of the Local Universe (CLU) experiment aims to construct a spectroscopically complete sample of transients occurring in galaxies from the CLU galaxy catalog. We identify 13 long-rising (>40 days) Type II supernovae from the volume-limited CLU experiment during a 3.5 year period from June 2018 to December 2021, approximately doubling the previously known number of these events. We present photometric and spectroscopic data of these 13 events, finding peak r-band absolute magnitudes ranging from -15.6 to -17.5 mag and the tentative detection of Ba II lines in 9 events. Using our CLU sample of events, we derive a long-rising Type II supernova rate of $1.37^{+0.26}_{-0.30}\times10^{-6}$ Mpc$^{-3}$ yr$^{-1}$, $\approx$1.4% of the total core-collapse supernova rate. This is the first volumetric rate of these events estimated from a large, systematic, volume-limited experiment.Comment: 32 pages, 17 figures, 5 tables. Submitted to Ap

An Ultraviolet Spectroscopic Atlas of Local Starbursts and Star-Forming Galaxies: The Legacy of FOS and GHRS

We present 46 rest-frame ultraviolet (UV) spectra of 28 local starburst and star-forming galaxies which were observed with the Faint Object Spectrograph (FOS) and the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) at a spectral resolution of a few 100 km/s. We compare the HST spectra with lower resolution International Ultraviolet Explorer (IUE) spectra of the same galaxies and find systematic differences: the bright star clusters targeted in HST's ~1 arcsec apertures provide about 15% of the starburst luminosity traced by IUE's 10 arcsec by 20 arcsec aperture; they are bluer and have stronger stellar-wind features suggesting that the HST apertures have preferentially been placed on the youngest areas of the burst. In contrast, lines arising from the interstellar medium (ISM) show similar equivalent widths in both the large and small aperture observations, suggesting similar ISM properties from larger to smaller scales. In order to quantify the UV spectral morphology of star-forming galaxies, we created a set of UV line indices similar to the standard optical Lick indices. We discuss the relation between the UV spectral morphology and the properties of the galaxy host. We present our atlas of FOS and GHRS spectra both in print and electronically. The data set is useful as a baseline for comparisons with observations of the rest-frame UV spectra of star-forming galaxies at high redshift.Comment: Accepted by A