Young, metal-enriched cores in early-type dwarf galaxies in the Virgo cluster based on colour gradients

Early-type dwarf galaxies are not simply featureless, old objects, but were found to be much more diverse, hosting substructures and a variety of stellar population properties. To explore the stellar content of faint early-type galaxies, and to investigate in particular those with recent central star formation, we study colours and colour gradients within one effective radius in optical (g-r) and near-infrared (i-H) bands for 120 Virgo cluster early types with -19 mag < $M_{r}$ < -16 mag. Twelve galaxies turn out to have blue cores, when defined as g-r colour gradients larger than 0.10 mag/$R_{\rm eff}$, which represents the positive tail of the gradient distribution. For these galaxies, we find that they have the strongest age gradients, and that even outside the blue core, their mean stellar population is younger than the mean of ordinary faint early types. The metallicity gradients of these blue-cored early-type dwarf galaxies are, however, in the range of most normal faint early types, which we find to have non-zero gradients with higher central metallicity. The blue central regions are consistent with star formation activity within the last few 100 Myr. We discuss that these galaxies could be explained by environmental quenching of star formation in the outer galaxy regions, while the inner star formation activity has continued

The hELENa project - II. Abundance distribution trends of early-type galaxies: from dwarfs to giants

In this second paper of T$h$e role of $E$nvironment in shaping $L$ow-mass $E$arly-type $N$earby g$a$laxies (hELENa) series we study [Mg/Fe] abundance distribution trends of early-type galaxies observed with the SAURON integral field unit, spanning a wide range in mass and local environment densities: 20 low-mass early-types (dEs) of Sybilska et al. (2017) and 258 massive early types (ETGs) of the $ATLAS^{3D}$ project, all homogeneously reduced and analyzed. We show that the [Mg/Fe] ratios scale with velocity dispersion ($\sigma$) at fixed [Fe/H] and that they evolve with [Fe/H] along similar paths for all early-types, grouped in bins of increasing local and global {$\sigma$}, as well as the second velocity moment $V_{rms}$, indicating a common inside-out formation pattern. We then place our dEs on the [Mg/Fe] $vs.$ [Fe/H] diagram of Local Group galaxies and show that dEs occupy the same region and show a similar trend line slope in the diagram as the high-metallicity stars of the Milky Way and the Large Magellanic Cloud. This finding extends the similar trend found for dwarf spheroidal $vs.$ dwarf irregular galaxies and supports the notion that dEs have evolved from late-type galaxies that have lost their gas at a point of their evolution, which likely coincided with them entering denser environments.Comment: Accepted for publication in MNRA

On the accretion of a new group of galaxies onto Virgo: III. The stellar population radial gradients of dEs

Using MUSE data, we investigate the radial gradients of stellar population properties (namely age, [M/H], and the abundance ratio of $\alpha$ elements [$\alpha$/Fe]) for a sample of nine dwarf early-type (dE) galaxies with log(M$_{\star}$/M$_{\odot}$) $\sim$ 9.0 and an infall time onto the Virgo cluster of 2-3Gyr ago. We followed a similar approach as in Bidaran et al. (2022) to derive their stellar population properties and star formation histories (SFHs) through fitting observed spectral indices and full spectral fitting, respectively. We find that these nine dE galaxies have truncated [Mg/Fe]vs.[Fe/H] profiles than equally-massive Virgo dE galaxies with longer past infall times. Short profiles of three dE galaxies are the result of their intense star formation which has been quenched long before their accretion onto the Virgo cluster, possibly as a result of their group environment. In the remaining six dE galaxies, profiles mainly trace a recent episode of star burst within 0.4R$_{\rm e}$ which results in higher light-weighted [$\alpha$/Fe] values. The latter SFH peak can be due to ram pressure exerted by the Virgo cluster at the time of the accretion of the dE galaxies. Also, we show that younger, more metal-rich and less $\alpha$-enhanced stellar populations dominate their inner regions (i.e., < 0.4R$_{\rm e}$) resulting in mainly flat $\nabla_{\rm age}$, negative $\nabla_{\rm [M/H]}$ and positive $\nabla_{\rm [\alpha/Fe]}$. We find that with increasing log($\sigma_{\rm Re}$) of dE galaxies, $\nabla_{\rm age}$ and $\nabla_{\rm [\alpha/Fe]}$ flatten, and the latter correlation persists even after including early-type galaxies up to log($\sigma_{\rm Re}$ $\sim$ 2.5), possibly due to the more extended star formation activity in the inner regions of dEs, as opposed to more massive early-type galaxies.Comment: 18 pages, 8 figures, accepted in MNRA

On the accretion of a new group of galaxies onto Virgo – III. The stellar population radial gradients of dEs

Using MUSE data, we investigate the radial gradients of stellar population properties (namely age, [M/H], and the abundance ratio of α elements [α/Fe]) for a sample of nine dwarf early-type (dE) galaxies with log(M/M) ∼ 9.0 and an infall time onto the Virgo cluster of 2–3 Gyr ago. We followed a similar approach as in Bidaran et al. to derive their stellar population properties and star formation histories (SFHs) through fitting observed spectral indices and full spectral fitting, respectively. We find that these nine dE galaxies have truncated [Mg/Fe] versus [Fe/H] profiles than equally massive Virgo dE galaxies with longer past infall times. Short profiles of three dE galaxies are the result of their intense star formation which has been quenched long before their accretion onto the Virgo cluster, possibly as a result of their group environment. In the remaining six dE galaxies, profilesmainly trace a recent episode of star burst within 0.4Re which results in higher light-weighted [α/Fe] values. The latter SFH peak can be due to ram pressure exerted by the Virgo cluster at the time of the accretion of the dE galaxies. Also, we show that younger, more metal-rich, and less α-enhanced stellar populations dominate their inner regions (i.e. < 0.4Re) resulting in mainly flat ∇age, negative ∇[M/H], and positive ∇[α/Fe]. We find that with increasing log(σ Re) of dE galaxies, ∇age and ∇[α/Fe] flatten, and the latter correlation persists even after including early-type galaxies up to log(σ Re ∼ 2.5), possibly due to the more extended star formation activity in the inner regions of dEs, as opposed to more massive early-type galaxies

Astrometry24.NET – precise astrometry for SST and NEO

Astrometry24.NET (A24N) is the first openly available online tool for precise astrometry of astronomical objects able to provide an astrometric solution for both point sources as well as streaks left by non-sidereal moving objects (satellites and space debris or NearEarth Objects - NEOs). A24N is accessible by the end user through three interfaces a) a web browser with modern, responsive UI, b) a cross-platform Command Line Interface (CLI) and c) programmatically through a RESTful API. It makes use of state-of-the-art IT technologies and specifically developed detection and analysis algorithms, utilizing cloud premises, which allow for inexpensive Service Level Agreement (SLA) up to 99.9%. Processing is available on-demand, with optimized load balancing, depending on the actual usage. The architecture of the system, catalogue support, and the astrometric engine behind A24N are first described, followed by the description of the dedicated web portal, built on top of Sybilla Technologies AstroDrive engine, which enables the user to easily upload, store, search, view and manipulate their data. We show the results obtained by the service from synthetic and real data sets. NEO data from ESA Optical Ground Station (OGS) were used, reduced with A24N, Astrometrica and compared (as ground truth) with ephemerides provided from JPL Horizons. For the simulated data tests, a dedicated synthetic frames generator has been developed, which allows one to reproduce all major error sources and isolate their effect. A24N has been tried and tested on a number of data sets from various observatories, including the ESA OGS and the Test Bed Telescope (TBT) in Spain, as well as observatories belonging to the Open University (UK), Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences (Poland), Max Planck Institute for Extraterrestrial Physics (Germany, COG), Mt. Suhora Observatory of the Pedagogical University in Cracow (Poland), and Comenius University (Slovakia). Long-term monitoring of the COG sensor accuracy, precision and offset has been conducted, as well as observations of Geostationary Orbit (GEO) drifters to test the algorithms and architecture in the production environment. The results of the campaign are presented

Use of molecular biology techniques to identify genetically modified organisms (GMOs) in food products – do you know what you eat?

tekst w j. pol. i ang.Ocena poprawności oznaczeń produktów spożywczych pod kątem zawartości genetycznie modyfikowanych organizmów (GMO)

The hELENa project - I. Stellar populations of early-type galaxies linked with local environment and galaxy mass

We present the first in a series of papers in The role of Environment in shaping Low-mass Early-type Nearby galaxies (hELENa) project. In this paper, we combine our sample of 20 low-mass early types (dEs) with 258 massive early types (ETGs) from the ATLAS3D survey - all observed with the SAURON integral field unit - to investigate early-type galaxies' stellar population scaling relations and the dependence of the population properties on local environment, extended to the low-σ regime of dEs. The ages in our sample show more scatter at lower σ values, indicative of less massive galaxies being affected by the environment to a higher degree. The shape of the age-σ relations for cluster versus non-cluster galaxies suggests that cluster environment speeds up the placing of galaxies on the red sequence. While the scaling relations are tighter for cluster than for the field/group objects, we find no evidence for a difference in average population characteristics of the two samples. We investigate the properties of our sample in the Virgo cluster as a function of number density (rather than simple clustrocentric distance) and find that dE ages correlate with the local density such that galaxies in regions of lower density are younger, likely because they are later arrivals to the cluster or have experienced less pre-processing in groups, and consequently used up their gas reservoir more recently. Overall, dE properties correlate more strongly with density than those of massive ETGs, which was expected as less massive galaxies are more susceptible to external influences

On the accretion of a new group of galaxies on to Virgo: I. Internal kinematics of nine in-falling dEs

Galaxy environment has been shown to play an important role in transforming late-type, star-forming galaxies to quiescent spheroids. This transformation is expected to be more severe for low-mass galaxies (M < 10(10) M-circle dot) in dense galaxy groups and clusters, mostly due to the influence of their past host haloes (also known as pre-processing) and their present-day environments. For the first time, in this study, we investigate a sample of nine early-type dwarf galaxies (dEs) that were accreted as a likely bound group on to the Virgo galaxy cluster about 2-3 Gyr ago. Considering this special condition, these nine dEs may provide a test bed for distinguishing between the influence of the Virgo galaxy cluster and the effects of the previous host halo on their current properties. Specifically, we use vr-umusF integral-field unit spectra to derive their kinematics and specific angular momentum (lambda(R)) profiles. Wc observe a spread in the lambda(R) profiles of our sample dEs, finding that the lambda(R) profiles of half of them are as high as those of low-mass field galaxies. The remaining dEs exhibit lambda(R) profiles as low as those of Virgo dEs that were likely accreted longer ago. Moreover, we detect nebular emission in one dE with a gas velocity offset suggesting ongoing gas stripping in Virgo. We suggest that the low-lambda(R) dEs in our sample were processed by their previous host halo, prior to their infall to Virgo, and that the high-lambda(R) dEs may be experiencing ram pressure stripping in Virgo

The Pleasure of Inter-Texts. On Poems Concerting in the Key of o (Józef Czechowicz's przez kresy [Through the Borderland]

The literary method demonstrated by Białoszewski that allows one to recognise the poetics of the poem przez kresy might be divided into two ways: into adding words to words and into words that are concerting. Both these methods have a lot in common with sound organisation. The case of a special key of „O” proves the most interesting. In the poem Podłogo, błogosław, from which „the key of O” is derived, the words are concerting, proud of the fact that they are so nice in their sound arrangement. I understand the key of O as a set of alliterations, paronomasias concentrated on the sound „o”. When reading Czechowicz's lyric we think of the intra-textual weave appearing in Białoszewski's poem. At the same time a chain of associations leads us to alliterative measures used by the old masters describing the turns of the... world