An Origin of the Huge Far-Infrared Luminosity of Starburst Mergers

Recently Taniguchi and Ohyama found that the higher $^{12}$CO to $^{13}$CO integrated intensity ratios at a transition $J$=1--0, $R = I(^{12}$CO)$/I(^{13}$CO) $\gtrsim 20$, in a sample of starburst merging galaxies such as Arp 220 are mainly attributed to the depression of $^{13}$CO emission with respect to $^{12}$CO. Investigating the same sample of galaxies analyzed by Taniguchi & Ohyama, we find that there is a tight, almost linear correlation between the dust mass and $^{13}$CO luminosity. This implies that dust grains are also depressed in the high-$R$ starburst mergers, leading to the higher dust temperature ($T_{\rm d}$) in them because of the relative increase in the radiation density. Nevertheless, the average dust mass ($M_{\rm d}$) of the high-$R$ starburst mergers is higher significantly than that of non-high $R$ galaxies. This is naturally understood because the galaxy mergers could accumulate a lot of dust grains from their progenitor galaxies together with supply of dust grains formed newly in the star forming regions. Since $L$(FIR) $\propto M_{\rm d} T_{\rm d}^5$ given the dust emissivity law, $S_\nu \propto \lambda^{-1}$, the increases in both $M_{\rm d}$ and $T_{\rm d}$ explain well why the starburst mergers are so bright in the FIR. We discuss that the superwind activity plays an important role in destroying dust grains as well as dense gas clouds in the central region of mergers.Comment: 10 pages (aaspp4.sty), 3 postscript figures (embedded). Accepted for publication in Astrophysical Journal Letter

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

Molecular clouds in the centers of galaxies: Constraints from HCN and CO-13 line emission

We have searched for HCN J=1-0 line emission in the centers of 12 galaxies and have detected it in 10 of them. We have obtained complementary data on J=1-0 and 2-1 transitions of CO-12 and CO-13 in these systems. The ratio of integrated intensities, I(CO 1-0)/I(HCN 1-0) = 25 +/- 11 for this sample. We find that HCN emission of this strength can be produced under conditions of subthermal excitation. In combination with the line ratios in CO and CO-13, HCN puts constraints on the mean conditions of molecular clouds and on the mix of cloud types within the projected beam

Canopy uptake dominates nighttime carbonyl sulfide fluxes in a boreal forest

Nighttime vegetative uptake of carbonyl sulfide (COS) can exist due to the incomplete closure of stomata and the light independence of the enzyme carbonic anhydrase, which complicates the use of COS as a tracer for gross primary productivity (GPP). In this study we derived nighttime COS fluxes in a boreal forest (the SMEAR II station in Hyytiälä, Finland; 61°51′ N, 24°17′ E; 181 m a.s.l.) from June to November 2015 using two different methods: eddy-covariance (EC) measurements (FCOS-EC) and the radon-tracer method (FCOS-Rn). The total nighttime COS fluxes averaged over the whole measurement period were −6.8 ± 2.2 and −7.9 ± 3.8 pmol m−2 s−1 for FCOS-Rn and FCOS-EC, respectively, which is 33–38 % of the average daytime fluxes and 21 % of the total daily COS uptake. The correlation of 222Rn (of which the source is the soil) with COS (average R2  =  0.58) was lower than with CO2 (0.70), suggesting that the main sink of COS is not located at the ground. These observations are supported by soil chamber measurements that show that soil contributes to only 34–40 % of the total nighttime COS uptake. We found a decrease in COS uptake with decreasing nighttime stomatal conductance and increasing vapor-pressure deficit and air temperature, driven by stomatal closure in response to a warm and dry period in August. We also discuss the effect that canopy layer mixing can have on the radon-tracer method and the sensitivity of (FCOS-EC) to atmospheric turbulence. Our results suggest that the nighttime uptake of COS is mainly driven by the tree foliage and is significant in a boreal forest, such that it needs to be taken into account when using COS as a tracer for GPP

A high-resolution mm and cm study of the obscured LIRG NGC 4418 - A compact obscured nucleus fed by in-falling gas?

The aim of this study is to constrain the dynamics, structure and feeding of the compact nucleous of NGC4418, and to reveal the nature of the main hidden power source: starburst or AGN. We obtained high spatial resolution observations of NGC4418 at 1.4 and 5 GHz with MERLIN, and at 230 and 270 GHz with the SMA very extended configuration. We use the continuum morphology and flux density to estimate the size of the emitting region, the star formation rate and the dust temperature. Emission lines are used to study the kinematics through position-velocity diagrams. Molecular emission is studied with population diagrams and by fitting an LTE synthetic spectrum. We detect bright 1mm line emission from CO, HC3N, HNC and C34S, and 1.4 GHz absorption from HI. The CO 2-1 emission and HI absorption can be fit by two velocity components at 2090 and 2180 km s-1. We detect vibrationally excited HC3N and HNC, with Tvib 300K. Molecular excitation is consistent with a layered temperature structure, with three main components at 80, 160 and 300 K. For the hot component we estimate a source size of less than 5 pc. The nuclear molecular gas surface density of 1e4 Msun pc-2 is extremely high, and similar to that found in the ultra-luminous infrared galaxy (ULIRG) Arp220. Our observations confirm the the presence of a molecular and atomic in-flow, previously suggested by Herschel observations, which is feeding the activity in the center of NGC4418. Molecular excitation confirms the presence of a very compact, hot dusty core. If a starburst is responsible for the observed IR flux, this has to be at least as extreme as the one in Arp220, with an age of 3-10 Myr and a star formation rate >10 Msun yr-1. If an AGN is present, it must be extremely Compton-thick.Comment: 18 pages, 11 figures, Accepted for publication by A&A on 10/6/201

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

HNC, HCN and CN in Seyfert galaxies

Bright HNC 1--0 emission has been found towards several Seyfert galaxies. This is unexpected since traditionally HNC is a tracer of cold (10 K) gas, and the molecular gas of luminous galaxies like Seyferts is thought to have bulk kinetic temperatures surpassing 50 K. In this work we aim to distinguish the cause of the bright HNC and to model the physical conditions of the HNC and HCN emitting gas. We have used SEST, JCMT and IRAM 30m telescopes to observe HNC 3-2 and HCN 3-2 line emission in a selection of 5 HNC-luminous Seyfert galaxies. We estimate and discuss the excitation conditions of HCN and HNC in NGC 1068, NGC 3079, NGC 2623 and NGC 7469, based on the observed 3-2/1-0 line intensity ratios. We also observed CN 1-0 and 2-1 emission and discuss its role in photon and X-ray dominated regions. HNC 3-2 was detected in 3 galaxies (NGC 3079, NGC 1068 and NGC 2623). HCN 3-2 was detected in NGC 3079, NGC 1068 and NGC 1365. The HCN 3-2/1-0 ratio is lower than 0.3 only in NGC 3079, whereas the HNC 3-2/1-0 ratio is larger than 0.3 only in NGC 2623. The HCN/HNC 1-0 and 3-2 line ratios are larger than unity in all the galaxies. The HCN/HNC 3-2 line ratio is lower than unity only in NGC 2623, similar to Arp 220, Mrk 231 and NGC 4418. In three of the galaxies the HNC emissions emerge from gas of densities n<10^5 cm^3, where the chemistry is dominated by ion-neutral reactions. In NGC 1068 the emission of HNC emerges from lower (<10^5 cm^3) density gas than HCN (>10^5 cm^3). Instead, the emissions of HNC and HCN emerge from the same gas in NGC 3079. The observed HCN/HNC and CN/HCN line ratios favor a PDR scenario, rather than an XDR one. However, the N(HNC)/N(HCN) column density ratios obtained for NGC 3079 can be found only in XDR environments.Comment: Accepted for publication in A&A. A selection of this paper will be presented as a poster in the FIR workshop 2007, held at Bad Honnef, Germany. High resolution figures in original paper. 16 pages, 8 figure

Comment on : Decrease of anticholinergic drug use in nursing home residents in the United States

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Comment on : Decrease of anticholinergic drug use in nursing home residents in the United States

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