Constraints on the parameters of radiatively decaying dark matter from the dark matter halo of the Milky Way and Ursa Minor

We improve the earlier restrictions on parameters of the dark matter (DM) in the form of a sterile neutrino. The results were obtained from non-observing the DM decay line in the X-ray spectrum of the Milky Way (using the recent XMM-Newton PN blank sky data). We also present a similar constraint coming from the recent XMM-Newton observation of Ursa Minor -- dark, X-ray quiet dwarf spheroidal galaxy. The new Milky way data improve on (by as much as the order of magnitude at masses ~3.5 keV) existing constraints. Although the observation of Ursa Minor has relatively poor statistics, the constraints are comparable to those recently obtained using observations of the Large Magellanic Cloud or M31. This confirms a recent proposal that dwarf satellites of the MW are very interesting candidates for the DM search and dedicated studies should be made to this purpose.Comment: 8 pp. v.2 - Final version to appear in A&

Galaxy Clusters in the Swift/BAT era II: 10 more Clusters detected above 15 keV

We report on the discovery of 10 additional galaxy clusters detected in the ongoing Swift/BAT all-sky survey. Among the newly BAT-discovered clusters there are: Bullet, Abell 85, Norma, and PKS 0745-19. Norma is the only cluster, among those presented here, which is resolved by BAT. For all the clusters we perform a detailed spectral analysis using XMM-Newton and Swift/BAT data to investigate the presence of a hard (non-thermal) X-ray excess. We find that in most cases the clusters' emission in the 0.3-200keV band can be explained by a multi-temperature thermal model confirming our previous results. For two clusters (Bullet and Abell 3667) we find evidence for the presence of a hard X-ray excess. In the case of the Bullet cluster, our analysis confirms the presence of a non-thermal, power-law like, component with a 20-100 keV flux of 3.4 \times 10-12 erg cm-2 s-1 as detected in previous studies. For Abell 3667 the excess emission can be successfully modeled as a hot component (kT=~13keV). We thus conclude that the hard X-ray emission from galaxy clusters (except the Bullet) has most likely thermal origin.Comment: Accepted for publication by Ap

Exploring the spreading layer of GX 9+9 using RXTE and INTEGRAL

We have fitted ~200 RXTE and INTEGRAL spectra of the neutron star LMXB GX 9+9 from 2002-2007 with a model consisting of a disc blackbody and another blackbody representing the spreading layer (SL), i.e. an extended accretion zone on the NS surface as opposed to the more traditional disc-like boundary layer. Contrary to theory, the SL temperature was seen to increase towards low SL luminosities, while the approximate angular extent had a nearly linear luminosity dependency. Comptonization was not required to adequately fit these spectra. Together with the ~70 degree upper bound of inclination implied by the lack of eclipses, the best-fitting normalization of the accretion disc blackbody component implies a distance of ~10 kpc, instead of the usually quoted 5 kpc.Comment: 14 pages, 10 figures, accepted for publication in MNRA

Static Pressure of Hot Gas: Its Effect on the Gas Disks of Galaxies

The static pressure of the hot gas that fills clusters and groups of galaxies can affect significantly the volume density and thickness of the gas disks in galaxies. In combination with the dynamic pressure, the static pressure allows several observed peculiarities of spiral galaxies surrounded by a hot medium to be explained.Comment: 9 pages, 2 figures. This is a slightly modified version of the paper published in Astronomy Letters 2008, Vol. 34, No 11, p. 73

Technical Note: Multispectral lidar time series of pine canopy chlorophyll content

201

Opetusryhmän merkitys ja tukeminen peruskoulussa

Tiivistelmä. Kandidaatintutkielma käy läpi narratiivisen kirjallisuuskatsauksen avulla opetusryhmän merkitystä ja sen tukemista koulukontekstissa. Tutkielman pohjana toimii aiemmin tehdyt tutkimukset ja kasvatustieteellinen kirjallisuus. Perusopetuksen opetussuunnitelman perusteissa (2014) opetusryhmät tulevat esille monissa eri kohdissa, mikä tarkoittaa opetusryhmän tärkeyttä koulun arjessa. Perusopetuksen opetussuunnitelman perusteissa (2014, 34–35) sanotaan esimerkiksi, että ”Jokaisella opettajalla on vastuu opetusryhmänsä toiminnasta, oppimisesta ja hyvinvoinnista. Huolehditaan siitä, että oppilaat saavat kokemuksia yhteistyöstä ja demokraattisesta toiminnasta omassa opetusryhmässä, koulussa ja sen lähiympäristössä sekä erilaisissa verkostoissa.” Tutkielmassa käsitellään opetusryhmän tärkeyttä lapselle. Opetusryhmät ovat lapselle vertaisryhmiä. Siellä lapset ovat keskenään tasavertaisia muiden jäsenten kanssa ja heidän kehityksensä on samalla tasolla. Lapsi oppii todella paljon vertaisten kanssa käymistä vuorovaikutustilanteista ja ne ovat tärkeitä lapsen kehityksen kannalta. Perusopetuksen opetussuunnitelman perusteiden (2014, 39) mukaan opetusryhmällä täytyy olla opettaja, joka vastaa oppilaiden turvallisuudesta ja hyvinvoinnista niin, että jokaisella oppilaalla on turvalliset vuorovaikutus mahdollisuudet edistävään oppimiseen ja kehitykseen. Opettajalla ja koululla on siis suuri vastuu opetusryhmästä. Nämä asiat nousivat myös esille aiemmissa tutkimuksissa, joten käyn myös läpi, miten opettaja ja koulu voivat tukea opetusryhmää. Tutkielma käsittelee yhteistoiminnallista ryhmätyöskentelyä, joka auttaa oppilaita työskentelemään ja tulemaan toimeen opetusryhmässä. Pienikin yhteistoiminnallisen ryhmätyön käyttäminen edistää opetusryhmän yhteistä luokkahenkeä

Outlining multi-purpose forest inventories to assess the ecosystem approach in forestry

A summary and discussion of selected published results on the current and potential role of forest inventories (with particular reference to the national ones) are presented in the light of the challenges posed by society and policy decisions in the environmental sector. The analysis concentrates mainly on the ecological and socio-economic aspects of the question and on forest inventories’ potential contribution to achieving sustainable forest management.L'articolo è diponibile sul sito dell'editore wwww.tandf.co.uk/journals

Changing climate and outbreaks of forest pest insects in a cold northern country, Finland

201

Fermi Discovery of Gamma-Ray Emission from NGC 1275

We report the discovery of high-energy (E>100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the Fermi Gamma ray Space Telescope. The positional center of the gamma-ray source is only ~3' away from the NGC 1275 nucleus, well within the 95% LAT error circle of ~5'.The spatial distribution of gamma-ray photons is consistent with a point source. The average flux and power-law photon index measured with the LAT from 2008 August 4 to 2008 December 5 are F_gamma = (2.10+-0.23)x 10^{-7} ph (>100 MeV) cm^{-2} s^{-1} and Gamma = 2.17+-0.05, respectively. The measurements are statistically consistent with constant flux during the four-month LAT observing period.Previous EGRET observations gave an upper limit of F_gamma 100 MeV) cm^{-2} s^{-1} to the gamma-ray flux from NGC 1275. This indicates that the source is variable on timescales of years to decades, and therefore restricts the fraction of emission that can be produced in extended regions of the galaxy cluster. Contemporaneous and historical radio observations are also reported. The broadband spectrum of NGC 1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.Comment: 27 pages, 7 figures, Accepted for publication in the Astrophysical Journa