2,180 research outputs found
Star-formation in the central kpc of the starburst/LINER galaxy NGC1614
A high angular resolution, multi-wavelength study of the LINER galaxy NGC1614
has been carried out. OVRO CO 1-0 observations are presented together with
extensive multi-frequency radio continuum and HI absorption observations with
the VLA and MERLIN. Toward the center of NGC1614, we have detected a ring of
radio continuum emission with a radius of 300 pc. This ring is coincident with
previous radio and Paschen-alpha observations. The dynamical mass of the ring
based on HI absorption is 3.1 x 10E9 Msun. The peak of the integrated CO 1-0
emission is shifted by 1" to the north-west of the ring center and a
significant fraction of the CO emission is associated with a crossing dust
lane. An upper limit to the molecular gas mass in the ring region is 1.7 x 10E9
Msun. Inside the ring, there is a north to south elongated 1.4GHz radio
continuum feature with a nuclear peak. This peak is also seen in the 5GHz radio
continuum and in the CO. We suggest that the R=300 pc star forming ring
represents the radius of a dynamical resonance - as an alternative to the
scenario that the starburst is propagating outwards from the center into a
molecular ring. The ring-like appearance probably part of a spiral structure.
Substantial amounts of molecular gas have passed the radius of the ring and
reached the nuclear region. The nuclear peak seen in 5GHz radio continuum and
CO is likely related to previous star formation, where all molecular gas was
not consumed. The LINER-like optical spectrum observed in NGC1614 may be due to
nuclear starburst activity, and not to an Active Galactic Nucleus (AGN).
Although the presence of an AGN cannot be excluded.Comment: Accepted by Astronomy and Astrophysics, 12 pages, 10 figure
Formation and evolution of dusty starburst galaxies I. A new method for deriving spectral energy distribution
We present a new numerical code which is designed to derive a spectral energy
distribution (SED) for an arbitrary spatial distribution of stellar and gaseous
components in a dusty starburst galaxy. We apply a ray tracing method to
numerical simulations and thereby estimate extinction and reemission of stellar
light by dusty gas in an explicitly self-consistent manner. By using this code,
we can investigate simultaneously dynamical and photometric evolution of a
dusty galaxy based on stellar and gaseous dynamical simulations. As an example,
we demonstrate when and how a major galaxy merger with dusty starburst becomes
an ultra-luminous infrared galaxy owing to strong internal dust extinction. We
furthermore discuss advantages and disadvantages of the present new code in
clarifying the nature and the origin of low and high redshift dusty starburst
galaxies.Comment: 44 pages 19 figures (11 color), accepted by Ap
Gamma-Ray Emission from Arp 220: Indications of an Active Galactic Nucleus
Extragalactic cosmic ray populations are important diagnostic tools for
tracking the distribution of energy in nuclei and for distinguishing between
activity powered by star formation versus active galactic nuclei (AGNs). Here,
we compare different diagnostics of the cosmic ray populations of the nuclei of
Arp 220 based on radio synchrotron observations and the recent gamma-ray
detection. We find the gamma-ray and radio emission to be incompatible; a joint
solution requires at minimum a factor of 4 - 8 times more energy coming from
supernovae and a factor of 40 - 70 more mass in molecular gas than is observed.
We conclude that this excess of gamma-ray flux in comparison to all other
diagnostics of star-forming activity indicates that there is an AGN present
that is providing the extra cosmic rays, likely in the western nucleus.Comment: 5 pages, 3 figures, 1 table, accepted for publication in MNRAS
Letter
New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere : a comparison between permafrost and non-permafrost areas
The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (similar to 1 km(2)) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R-2 values being similar to 0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were similar to 1.31 degrees C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6 degrees C, respectively. Soil properties had marginal effects on MAGT (effect size = 0.4-0.7 degrees C). For ALT, rainfall (effect size = 181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGTPeer reviewe
Putoaville ratkaisu : Työhönvalmennusta ja päihdekuntoutusta nuorille
PURA – toiminnasta työkyky -kehittämishanke toimi vuosina 2014–2017 Sytyke-Centren/Hengitysliitto ry:n, Kelan, Peruspalvelukuntayhtymä Kallion, Avominne-päihdeklinikan ja Kuntoutussäätiön yhteistyönä. Hankkeen PURA-nimi muodostuu sanoista ”putoaville ratkaisuja”. Hankkeessa kehitettiin ja järjestettiin PURA-valmennusta alle 29-vuotiaille nuorille, jotka tarvitsevat tukea ammattiin opiskelussa tai työelämään pääsyssä. Valmennukseen osallistuneilla nuorilla oli mielenterveyden pulmia, päihteiden käyttö haittasi ammatillisten suunnitelmien etenemistä tai nuoren elämäntilanne oli muuten haastava. Valmennuksen tavoitteena oli edistää syrjäytymisvaarassa olevien nuorten kuntoutumista, työelämävalmiuksien parantumista ja työelämään sijoittumista. Valmennus koostui kolmesta osasta: toiminnallisesta työ- ja toimintakyvyn arviointijaksosta, työkykyvalmennusjaksosta ja tarvittaessa päihdekuntoutusjaksosta. Hankkeen arviointitutkimuksen tehtävänä oli selvittää, minkälaiset elementit edistävät kohderyhmän nuorten edellytyksiä sitoutua kuntoutukseen ja saavuttaa sille asetettuja tavoitteita. Aineiston muodostivat valmennukseen osallistuneilta nuorilta sekä valmennuksesta vastaavilta ammattilaisilta kerätyt kerronnalliset haastattelut. Analyysimetodina käytettiin laadullista aineistolähtöistä sisällönanalyysiä yhteisöllisen vuorovaikutuksen viitekehyksessä. Tuloksena todetaan, että PURA-valmennus tarjoaa mallin nuorten varhaisvaiheen kuntoutukselle. Sen tarkoituksena on saada syrjäytyneet nuoret palvelujen piiriin, jotta nuoren elämään liittyvää ongelmien vyyhtiä voidaan tarkastella yhdessä nuorten, kuntoutuksen moniammatillisen työryhmän ja ammatillisen palveluverkoston toimijoiden kanssa ja etsiä parhaita yksilöllisiä ratkaisuja nuoren ongelmiin. Nuorta tuetaan rakentamaan motiivia irrottautua päihteidenkäytöstä lisäämällä ymmärrystä päihdeongelman haitoista sekä osoittamalla päihteettömyyden olevan mahdollista ja ympäristön tarjoavan hänelle resursseja päihteidenkäytön lopettamiseen. Päihteidenkäytön lopettamisen lisäksi nuori tarvitsee tukea arkisten asioiden hoitamisen opetteluun sekä asumiseen ja toimeentuloon liittyviin asioihin. Kyvykkyyksiin kohdistuva arviointi auttaa nuoria tunnistamaan omia vahvuuksiaan. Arviointi on luonteeltaan monialaista, kannattelevaa työ- ja toimintakyvyn arviointia, joka tukee nuoren työ- ja toimintakykyä ja edistää siten kuntoutuksen tavoitteiden saavuttamista. Lisäksi se muistuttaa nuorta niistä vahvuuksista, joita ammattilaiset ovat todenneet hänellä olevan, mikä on tärkeää varsinkin, jos nuoren motivaatio kuntoutukseen uhkaa notkahtaa. Työkykyvalmennuksella edistetään nuorten työllistymiskykyä kokonaisvaltaisella työotteella, jossa valmennus kohdistetaan niin nuoren vapaa-ajan toimintaan, nuorten keskuudessa vallitsevaan työn tekemisen kulttuuriin kuin tukemaan nuorta onnistumaan työssä ja löytämään motivaation työelämäsiirtymää tukevaan opiskeluun. PURA-valmennuksessa pyritään kontrolloivan arvioinnin sijaan arvioinnilla kannattelemaan nuorta ja tukemaan hänen itsemääräämistään valinnan mahdollisuuksia osoittamalla ja valintoja tukemalla. Näillä keinoin voidaan tukea nuoren sisäistä voimantunnetta, jonka varassa hän rohkenee asettaa tavoitteita ja sitoutua kuntoutukseen. Heikossa asemassa, monien ongelmien vyyhdissä elävät nuoret, jotka ovat kokeneet useita epäonnistumisia ja joiden toimintakyky on alentunut, hyötyvät ammattilaisten nuoria kannattelevasta työskentelyotteesta. Näiden nuorten elämässä ammatillisesta kuntoutuksesta voi muodostua käännekohta ammatillisten suunnitelmien motivoidessa nuorta ratkaisevaan elämänmuutokseen
Spectra of Nearby Galaxies Measured with a New Very Broadband Receiver
Three-millimeter-wavelength spectra of a number of nearby galaxies have been
obtained at the Five College Radio Astronomy Observatory (FCRAO) using a new,
very broadband receiver. This instrument, which we call the Redshift Search
Receiver, has an instantaneous bandwidth of 36 GHz and operates from 74 to
110.5 GHz. The receiver has been built at UMass/FCRAO to be part of the initial
instrumentation for the Large Millimeter Telescope (LMT) and is intended
primarily for determination of the redshift of distant, dust-obscured galaxies.
It is being tested on the FCRAO 14m by measuring the 3mm spectra of a number of
nearby galaxies. There are interesting differences in the chemistry of these
galaxies.Comment: published in the Proceedings of the International Astronomical Union
(2008), 4. Vol 251, pp 251-256 Cambridge University Pres
Molecules as tracers of galaxy evolution: an EMIR survey. I. Presentation of the data and first results
We investigate the molecular gas properties of a sample of 23 galaxies in
order to find and test chemical signatures of galaxy evolution and to compare
them to IR evolutionary tracers. Observation at 3 mm wavelengths were obtained
with the EMIR broadband receiver, mounted on the IRAM 30 m telescope on Pico
Veleta, Spain. We compare the emission of the main molecular species with
existing models of chemical evolution by means of line intensity ratios
diagrams and principal component analysis. We detect molecular emission in 19
galaxies in two 8 GHz-wide bands centred at 88 and 112 GHz. The main detected
transitions are the J=1-0 lines of CO, 13CO, HCN, HNC, HCO+, CN, and C2H. We
also detect HC3N J=10-9 in the galaxies IRAS 17208, IC 860, NGC 4418, NGC 7771,
and NGC 1068. The only HC3N detections are in objects with HCO+/HCN<1 and warm
IRAS colours. Galaxies with the highest HC3N/HCN ratios have warm IRAS colours
(60/100 {\mu}m>0.8). The brightest HC3N emission is found in IC 860, where we
also detect the molecule in its vibrationally excited state.We find low HNC/HCN
line ratios (<0.5), that cannot be explained by existing PDR or XDR chemical
models. Bright HC3N emission in HCO+-faint objects may imply that these are not
dominated by X-ray chemistry. Thus the HCN/HCO+ line ratio is not, by itself, a
reliable tracer of XDRs. Bright HC3N and faint HCO+ could be signatures of
embedded starformation, instead of AGN activity
HCN to HCO^+ Millimeter Line Diagnostics of AGN Molecular Torus I : Radiative Transfer Modeling
We explore millimeter line diagnostics of an obscuring molecular torus
modeled by a hydrodynamic simulation with three-dimensional nonLTE radiative
transfer calculations. Based on the results of high-resolution hydrodynamic
simulation of the molecular torus around an AGN, we calculate intensities of
HCN and HCO^{+} rotational lines as two representative high density tracers.
The three-dimensional radiative transfer calculations shed light on a
complicated excitation state in the inhomogeneous torus, even though a
spatially uniform chemical structure is assumed. Our results suggest that HCN
must be much more abundant than HCO^{+} in order to obtain a high ratio
() observed in some of the nearby galaxies. There is a
remarkable dispersion in the relation between integrated intensity and column
density, indicative of possible shortcomings of HCN(1-0) and HCO^{+}(1-0) lines
as high density tracers. The internal structures of the inhomogeneous molecular
torus down to subparsec scale in external galaxies will be revealed by the
forthcoming Atacama Large Millimeter/submillimeter Array (ALMA). The
three-dimensional radiative transfer calculations of molecular lines with
high-resolution hydrodynamic simulation prove to be a powerful tool to provide
a physical basis for molecular line diagnostics of the central regions of
external galaxies.Comment: 29 pages, 13 figures, Accepted for publication in ApJ, For high
resolution figures see http://alma.mtk.nao.ac.jp/~masako/MS72533v2.pd
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