The Bar Pattern Speed of NGC 1433 Estimated Via Sticky-Particle Simulations

We present detailed numerical simulations of NGC 1433, an intermediate-type barred spiral showing strong morphological features including a secondary bar, nuclear ring, inner ring, outer pseudoring, and two striking, detached spiral arcs known as ``plumes.'' This galaxy is an ideal candidate for recreating the observed morphology through dynamical models and determining the pattern speed. We derived a gravitational potential from an $H$-band image of the galaxy and simulated the behavior of a two-dimensional disk of 100,000 inelastically colliding gas particles. We find that the closest matching morphology between a $B$-band image and a simulation occurs with a pattern speed of 0.89 km s$^{-1}$ arcsec$^{-1}$ $\pm$ 5-10%. We also determine that the ratio of corotation radius to the average published bar radius is 1.7 $\pm$ 0.3, with the ambiguity in the bar radius being the largest contributor to the error.Comment: Accepted for publication by The Astronomical Journal. 34 pages, 13 figures, 2 table

A monolithic collapse origin for the thin/thick disc structure of ESO 243-49

ESO 243-49 is a high-mass (circular velocity $v_{\rm c}\approx200\,{\rm km\,s^{-1}}$) edge-on S0 galaxy in the Abell 2877 cluster at a distance of $\sim95\,{\rm Mpc}$. To elucidate the origin of its thick disc, we use MUSE science verification data to study its kinematics and stellar populations. The thick disc emits $\sim80\%$ of the light at heights in excess of $3.5^{\prime\prime}$ ($1.6\,{\rm kpc}$). The rotation velocities of its stars lag by $30-40\,{\rm km\,s^{-1}}$ compared to those in the thin disc, which is compatible with the asymmetric drift. The thick disc is found to be more metal-poor than the thin disc, but both discs have old ages. We suggest an internal origin for the thick disc stars in high-mass galaxies. We propose that the thick disc formed either ${\rm a)}$ first in a turbulent phase with a high star formation rate and that a thin disc formed shortly afterwards, or ${\rm b)}$ because of the dynamical heating of a thin pre-existing component. Either way, the star formation in ESO 243-49 was quenched just a few Gyrs after the galaxy was born and the formation of a thin and a thick disc must have occurred before the galaxy stopped forming stars. The formation of the discs was so fast that it could be described as a monolithic collapse where several generations of stars formed in a rapid succession.Comment: Accepted for publication in A&A. The reduced data-cube as well as the data necessary to build the kinematic and stellar population maps are available at https://etsin.avointiede.fi/dataset/urn-nbn-fi-csc-kata2016092414291163237

Dynamical Simulations of NGC 2523 and NGC 4245

We present dynamical simulations of NGC 2523 and NGC 4245, two barred galaxies (types SB(r)b and SB(r)0/a, respectively) with prominent inner rings. Our goal is to estimate the bar pattern speeds in these galaxies by matching a sticky-particle simulation to the $B$-band morphology, using near-infrared $K_s$-band images to define the gravitational potentials. We compare the pattern speeds derived by this method with those derived in our previous paper using the well-known Tremaine-Weinberg continuity equation method. The inner rings in these galaxies, which are likely to be resonance features, help to constrain the dynamical models. We find that both methods give the same pattern speeds within the errors.Comment: 29 pages, 3 tables, 13 figures. Accepted for publication in The Astronomical Journa

Statistics of the structure components in S0s: implications for bar induced secular evolution

The fractions and dimension of bars, rings and lenses are studied in the Near-IR S0 galaxy Survey (NIRS0S). We find evidence that multiple lenses in some barred S0s are related to bar resonances in a similar manner as the inner and outer rings, for which the outer/inner length ratio 2. Inner lenses in the non-barred galaxies normalized to galaxy diameter are clearly smaller than those in the barred systems. Interestingly, these small lenses in the non-barred galaxies have similar sizes as barlenses (lens-like structures embedded in a bar), and therefore might actually be barlenses in former barred galaxies, in which the outer, more elongated bar component, has been destroyed. We also find that fully developed inner lenses are on average a factor 1.3 larger than bars, whereas inner rings have similar sizes as bars. The fraction of inner lenses is found to be constant in all family classes (A, AB, B). Nuclear bars appear most frequently among the weakly barred (AB) galaxies, which is consistent with the theoretical models by Maciejewski & Athanassoula (2008). Similar sized bars as the nuclear bars were detected in seven 'non-barred' S0s. Galaxy luminosity does not uniquely define the sizes of bars or bar-related structures, neither is there any upper limit in galaxy luminosity for bar formation. Although all the family classes cover the same range of galaxy luminosity, the non-barred (A) galaxies are on average 0.6 mag brighter than the strongly barred (B) systems. Overall, our results are consistent with the idea that bars play an important role in the formation of the structure components of galaxies. The fact that multiple lenses are common in S0s, and that at least the inner lenses can have very old stellar populations, implies that the last destructive merger, or major gas accretion event, must have taken place at a fairly high redshift.Comment: 36 pages (include 13 figures, 11 tables). Accepted to MNRAS 2013 Jan 2

Comparison of bar strengths in active and non-active galaxies

Bar strengths are compared between active and non-active galaxies for a sample of 43 barred galaxies. The relative bar torques are determined using a new technique (Buta and Block 2001), where maximum tangential forces are calculated in the bar region, normalized to the axisymmetric radial force field. We use JHK images of the 2 Micron All Sky Survey. We show a first clear empirical indication that the ellipticies of bars are correlated with the non-axisymmetric forces in the bar regions. We found that nuclear activity appears preferentially in those early type galaxies in which the maximum bar torques are weak and appear at quite large distances from the galactic center. Most suprisingly the galaxies with the strongest bars are non-active. Our results imply that the bulges may be important for the onset of nuclear activity, but that the correlation between the nuclear activity and the early type galaxies is not straightforward.Comment: MNRAS macro in tex format, 9 pages, 10 figure

Companions of Bright Barred Shapley Ames Galaxies

Companion galaxy environment for a subset of 78 bright and nearby barred galaxies from the Shapley Ames Catalog is presented. Among spiral barred galaxies there are Seyfert galaxies, galaxies with circumnuclear structures, galaxies not associated with any large scale galaxy cloud structure, galaxies with peculiar disk morphology (crooked arms) and galaxies with normal disk morphology; the list includes all Hubble types. The companion galaxy list includes number of companion galaxies within 20 diameters (D25), their Hubble type and projected separation distance. Additionally, companion environment was searched for four known active spiral galaxies, three of them are Seyfert galaxies, namely, NGC 1068, NGC 1097, NGC 5548 and one is a starburst galaxy, M82. Among the results obtained it is noted that the only spiral barred galaxy classified as Sy 1 in our list has no companions within a projected distance of 20 diameters; 6 out of 10 Sy 2 bar galaxies have no companions within 10 diamters, 6 out of 10 Sy 2 galaxies have one or more companions at projected separation distances between 10 and 20 diameters; 6 out of 12 galaxies with circumnuclear structures have 2 or more companions within 20 diametersComment: Accepted for publication in the Astronomical Journal, 40 pages incl. 3 figure

Digital sleep:expert evaluation of commercially available digital sleep trackers

Abstract. The use of digital technology has become a part of people’s life globally. The rapid digitalisation has created opportunities to understand and improve our sleep by monitoring sleep patterns with physiological parameters. In this study, three expert evaluators collect and analyse the sleep data from five different sleep monitoring devices: Dreem2, Fitbit Versa 3, Polar M430, SleepScore Max and Withings Sleep Analyzer. The data consists of three weeks sleep data from all devices, each participant using all devices simultaneously for one week. This study focuses on the device’s reliability on sleep monitoring, but also user experience is noticed with surveys filled in one week before assessment nights and one week during. In addition, technology expectation discussions were held to provide user perspective on the device. All devices had some problems recognising night-time wake ups and sleep restfulness. Reliability issues also came up when only two of five devices gave significantly lower sleep score after the user had many servings of alcohol. Devices recorded different amounts of sleep stages and had different algorithms to define sleep efficiency scoring to the user. The collected data and discussions from three expert evaluators, give an overall look on today’s marketed sleep tracking equipment compered to each other highlighting some issues that came up using the devices and analysing the sleep data. These results can be used for future work, applying the sleep data gathering timeline into a study of larger group of participants, to improve sleep technology equipment.Tiivistelmä. Digitaalisten laitteiden käyttö on tullut osaksi ihmisten elämää maailmanlaajuisesti. Nopeasti kehittyvä teknologia on tuonut ihmisille mahdollisuuksia ymmärtää ja parantaa untaan tutkimalla sitä erilaisten mitattavien fysiologisten parametrien avulla. Tutkimuksessamme kolme asiantuntija-arvioijaa kerää ja analysoi unidataa hyödyntäen viittä eri unta mittaavaa laitetta: Dreem2, Fitbit Versa 3, Polar M430, SleepScore Max ja Withings Sleep Analyzer. Käsiteltävä unidata koostuu kolmen viikon ajalta kerätystä datasta, jonka aikana jokainen osallistuja on käyttänyt kaikkia laitteita samanaikaisesti yhden viikon ajan. Tutkimus keskittyy laitteiden luotettavuuteen unen mittauksessa, mutta myös käyttäjäkokemus on huomioitu kyselyllä, joka täytetään viikon ajalta ennen unimittauksia ja unimittausviikon aikana. Lisäksi käyttökokemus näkökulma on huomioitu teknologiakeskusteluilla. Jokaisen laitteen kanssa ilmeni joitain ongelmia hereillä olon tunnistamisessa. Luottamusta laitteisiin heikensi myös, kun vain pieni osa laitteista antoi käyttäjälle selvästi alhaisemman arvon unen palauttavuudesta yönä, jota edelsi usea nautittu alkoholiannos. Laitteiden mittaamat univaiheiden määrät vaihtelivat myös merkittävästi ja laitteiden eri menetelmät mitata unen palauttavuutta nousivat esille tutkimuksessa. Kolmen asiantuntija-arvioijan keräämä ja analysoima data sekä teknologiakeskustelut, antavat kokonaiskuvan viidestä nykyaikaisesta unenmittauslaitteesta vertailtuna keskenään, ja nostavat esiin ongelmia laitteiden mittauksissa. Saadut tulokset voidaan hyödyntää tulevaisuudessa tutkimuksessa, jossa unidataa kerätään suuremmalta joukolta käyttäjiä, ja näin ollen kehittää unta mittaavia laitteita