The selective effect of environment on the atomic and molecular gas-to-dust ratio of nearby galaxies in the Herschel Reference Survey

We combine dust, atomic (HI) and molecular (H$_{2}$) hydrogen mass measurements for 176 galaxies in the Herschel Reference Survey to investigate the effect of environment on the gas-to-dust mass ($M_{\rm gas}/M_{\rm dust}$) ratio of nearby galaxies. We find that, at fixed stellar mass, the average $M_{\rm gas}/M_{\rm dust}$ ratio varies by no more than a factor of $\sim$2 when moving from field to cluster galaxies, with Virgo galaxies being slightly more dust rich (per unit of gas) than isolated systems. Remarkably, once the molecular and atomic hydrogen phases are investigated separately, we find that \hi-deficient galaxies have at the same time lower $M_{\rm HI}/M_{\rm dust}$ ratio but higher $M_{\rm H_{2}}/M_{\rm dust}$ ratio than \hi-normal systems. In other words, they are poorer in atomic but richer in molecular hydrogen if normalized to their dust content. By comparing our findings with the predictions of theoretical models, we show that the opposite behavior observed in the $M_{\rm HI}/M_{\rm dust}$ and $M_{\rm H_{2}}/M_{\rm dust}$ ratios is fully consistent with outside-in stripping of the interstellar medium (ISM), and is simply a consequence of the different distribution of dust, \hi\ and H$_{2}$ across the disk. Our results demonstrate that the small environmental variations in the total $M_{\rm gas}/M_{\rm dust}$ ratio, as well as in the gas-phase metallicity, do not automatically imply that environmental mechanisms are not able to affect the dust and metal content of the ISM in galaxies.Comment: 11 pages, 6 figures, 2 tables. Accepted for publication in MNRA

The slippery slope of dust attenuation curves: Correlation of dust attenuation laws with star-to-dust compactness up to z = 4

Aims. We investigate dust attenuation of 122 heavily dust-obscured galaxies detected with the Atacama Large Millimeter Array (ALMA) and Herschel in the COSMOS field. We search for correlations between dust attenuation recipes and the variation of physical parameters, mainly the effective radii of galaxies, their star formation rates (SFR), and stellar masses, and aim to understand which of the commonly used laws best describes dust attenuation in dusty star-forming galaxies at high redshift. Methods. We make use of the extensive photometric coverage of the COSMOS data combined with highly-resolved dust continuum maps from ALMA. We use CIGALE to estimate various physical properties of these dusty objects, mainly their SFR, their stellar masses and their attenuation. We infer galaxy effective radii (Re) using GALFIT in the Y band of HSC and ALMA continuum maps. We use these radii to investigate the relative compactness of the dust continuum and the extension of the rest-frame UV/optical Re(y)/Re(ALMA). Results. We find that the physical parameters calculated from our models strongly depend on the assumption of dust attenuation curve. As expected, the most impacted parameter is the stellar mass, which leads to a change in the "starburstiness" of the objects. We find that taking into account the relative compactness of star-to-dust emission prior to SED fitting is crucial, especially when studying dust attenuation of dusty star-forming galaxies. Shallower attenuation curves did not show a clear preference of compactness with attenuation, while the Calzetti attenuation curve preferred comparable spatial extent of unattenuated stellar light and dust emission. The evolution of the Re(UV)/Re(ALMA) ratio with redshift peeks around the cosmic noon in our sample of DSFGs, showing that this compactness is correlated with the cosmic SFR density of these dusty sources.Comment: 18 pages, 13 figures, accepted for publication in A&A. Abstract abridged for arXiv submissio

Welcome to the Twilight Zone: The Mid-Infrared Properties of Poststarburst Galaxies

We investigate the optical and Wide-field Survey Explorer (WISE) colors of "E+A" identified post-starburst galaxies, including a deep analysis on 190 post-starbursts detected in the 2{\mu}m All Sky Survey Extended Source Catalog. The post-starburst galaxies appear in both the optical green valley and the WISE Infrared Transition Zone (IRTZ). Furthermore, we find that post-starbursts occupy a distinct region [3.4]-[4.6] vs. [4.6]-[12] WISE colors, enabling the identification of this class of transitioning galaxies through the use of broad-band photometric criteria alone. We have investigated possible causes for the WISE colors of post-starbursts by constructing a composite spectral energy distribution (SED), finding that mid-infrared (4-12{\mu}m) properties of post-starbursts are consistent with either 11.3{\mu}m polycyclic aromatic hydrocarbon emission, or Thermally Pulsating Asymptotic Giant Branch (TP-AGB) and post-AGB stars. The composite SED of extended post- starburst galaxies with 22{\mu}m emission detected with signal to noise >3 requires a hot dust component to produce their observed rising mid-infrared SED between 12 and 22{\mu}m. The composite SED of WISE 22{\mu}m non-detections (S/N<3), created by stacking 22{\mu}m images, is also flat, requiring a hot dust component. The most likely source of this mid-infrared emission of these E+A galaxies is a buried active galactic nucleus. The inferred upper limit to the Eddington ratios of post-starbursts are 1e-2 to 1e-4, with an average of 1e-3. This suggests that AGNs are not radiatively dominant in these systems. This could mean that including selections able to identify active galactic nuclei as part of a search for transitioning and post-starburst galaxies would create a more complete census of the transition pathways taken as a galaxy quenches its star formation.Comment: 13 pages, 11 figures, accepted for publication in the Astrophysical Journa

The dust energy balance in the edge-on spiral galaxy NGC 4565

We combine new dust continuum observations of the edge-on spiral galaxy NGC 4565 in all Herschel/SPIRE (250, 350, 500 micron) wavebands, obtained as part of the Herschel Reference Survey, and a large set of ancillary data (Spitzer, SDSS, GALEX) to analyze its dust energy balance. We fit a radiative transfer model for the stars and dust to the optical maps with the fitting algorithm FitSKIRT. To account for the observed UV and mid-infrared emission, this initial model was supplemented with both obscured and unobscured star-forming regions. Even though these star-forming complexes provide an additional heating source for the dust, the far-infrared/submillimeter emission long wards of 100 micron is underestimated by a factor of 3-4. This inconsistency in the dust energy budget of NGC 4565 suggests that a sizable fraction (two-thirds) of the total dust reservoir (Mdust ~ 2.9e+8 Msun) consists of a clumpy distribution with no associated young stellar sources. The distribution of those dense dust clouds would be in such a way that they remain unresolved in current far-infrared/submillimeter observations and hardly comtribute to the attenuation at optical wavelengths. More than two-thirds of the dust heating in NGC 4565 is powered by the old stellar population, with localized embedded sources supplying the remaining dust heating in NGC 4565. The results from this detailed dust energy balance study in NGC 4565 is consistent with that of similar analyses of other edge-on spirals.Comment: 16 pages, 7 figures, accepted for publication in MNRA

Cold Dust but Warm Gas in the Unusual Elliptical Galaxy NGC 4125

Data from the Herschel Space Observatory have revealed an unusual elliptical galaxy, NGC 4125, which has strong and extended submillimeter emission from cold dust but only very strict upper limits to its CO and Hi emission. Depending on the dust emissivity, the total dust mass is 2-5 x 10(6) M-circle dot. While the neutral gas-to-dust mass ratio is extremely low (= 10(4) K faster than the dust is evaporated. If galaxies like NGC 4125, where the far-infrared emission does not trace neutral gas in the usual manner, are common at higher redshift, this could have significant implications for our understanding of high redshift galaxies and galaxy evolution.Canadian Space AgencyNatural Sciences and Engineering Research Council of CanadaAgenzia Spaziale Italiana (ASI) I/005/11/0BMVIT (Austria)ESA-PRODEX (Belgium)CEA/CNES (France)DLR (Germany)ASI/INAF (Italy)CICYT/MCYT (Spain)CSA (Canada)NAOC (China)CEA, (France)CNES (France)CNRS (France)ASI (Italy)MCINN (Spain)SNSB (Sweden)STFC (UK)NASA (USA)National Aeronautics and Space AdministrationAstronom

Probiotici i lekovito bilje u uzgoju šarana (cyprinus carpio l.) u zemljanim bazenima - uticaj na prirast ribe, zdravlje i proizvodne rezultate

The aim of the paper is to present the results of feeding carp with traditional grain diet (triticale + wheat) supplemented with probiotics and/or herbs. As probiotics, the EmFarma concentrate, provided by ProBiotics Polska, Poland,was used. This preparation contains consortia of the following microbial bacteria and fungi: Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactococcus diacetylactis, Lactococcus lactis, Streptococcus thermophilus, Bacillus subtilis var natto, Saccharomyces cerevisiae and Rhodopseudomonas palustris. The concentrate of probiotic microorganisms was added to the ground corn in an amount of 2 liters of preparation per 1 ton of feed. Prior to adding to the feedstuff, the probiotics were diluted in water. The amount of added water was approximately 10% of feed weight. After mixing probiotics with corn, the feed was left for two hours for swelling. The composition of herbs consisted of powdered Terminalia chebula, Phyllantus emblica, Andrographis paniculata, Tinospora cordifolia and Boerhaavia difusa. The herbal preparation was obtained from the Farmwet company, Poland. The blend of herbs was added in the amount of 3 kg per ton of ground corn feed. The powdered herbs were mixed with grinded corn, moistened with water amounting to approximately 10% of feed dose and left for two hours for swelling. Six feeding groups were examined: - I - natural food only (control group) - II - ground mix of corn - III - ground mix of corn supplemented with probiotics - IV - ground mix of corn supplemented with herbs - V - ground mix of corn supplemented with probiotics and herb - VI - pelleted feed Aller Aqua (referential group) Experimental diets were used for feeding carp fingerlings (C1), two-year restocking material (C2) and consumable carps (C3). Stocking densities of carp, were as follows: - for C1– 20000 ind./ha - for C2– 5000 ind./ha - for C3–1500 ind./ha The following parameters were measured and analyzed: - final body mass (g/ind.) - yield (kg/ha) - survival rate (S) - FCR (kg) - Fulton’s coefficient (F) - number of parasites (Trichodina–Trich., Chilodonella–Chil., Epistylis–Epist., Costia,) - level of lisozyme (mg/l) - level of gamma globulins (g/l)Cilj ovog rada je da prikaže rezultate ishrane šarana tradicionalnom smešom žitarica (tritikale + pšenica) sa dodatkom probiotika i/ili lekovitog bilja. Kao probiotik korišćen je koncentrat EmFarma, koji je obezbedio "ProBiotics Polska" iz Poljske. Ova smesa sadrži skup sledećih mikroorganizama, bakterija i gljivica: Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactococcus diacetylactis, Lactococcus lactis, Streptococcus thermophilus, Bacillus subtilis var natto, Saccharomyces cerevisiae and Rhodopseudomonas palustris. Koncentrat probiotskih mikroorganizama dodat je u mleveni kukuruz u količini od 2 litra preparata na 1 tonu hraniva. Pre dodavanja hranivima probiotski preparat je razređen u vodi. Količina dodate vode bila je oko 10% od težine hrane. Posle mešanja probiotika sa kukuruzom, hranivo je ostavljeno dva sata da nabubri. Lekovito bilje sastojalo se od praha Terminalia chebula, Phyllantus emblica, Andrographis paniculata, Tinospora cordifolia i Boerhaavia difusa. Biljni preparat dobijen je od kompanije Farmwet iz Poljske. Mešavina bilja dodata je u količini od 3 kg na tonu kukuruzne prekrupe. Bilje u prahu pomešano je sa prekrupom, zatim navlaženo vodom u količini od oko 10% od doze hrane i ostavljeno dva sata da nabubri. Ispitivanje je vršeno na šest hranidbenih grupa: - I - samo prirodna hrana (kontrolna grupa) - II - smeša sa kukuruznom prekrupom - III - smeša sa kukuruznom prekrupom obogaćena probioticima - IV - smeša sa kukuruznom prekrupom obogaćena lekovitim biljem - V - smeša sa kukuruznom prekrupom obogaćena probioticima i lekovitim biljem - VI - peletirana hrana Aller Aqua (referentna grupa) Eksperimentalne smeše korišćene su za ishranu šaranske mlađi (C1), dvogodišnjaka za dalji uzgoj (C2) i konzumnih šarana (C3). Gustine nasada šarana bile su sledeće: - za C1– 20000 jedinki/ha - za C2– 5000 jedinki/ha - za C3–1500 jedinki/ha Sledeći parametri su mereni i analizirani: - završna telesna masa (g/jedinka) - prinos (kg/ha) - stopa preživljavanja (S) - stopa konverzije hrane, FCR (kg) - Fultonov koeficijent (F) - broj parazita (Trichodina–Trich., Chilodonella–Chil., Epistylis–Epist., Costia,) - nivo lizozima (mg/l) - nivo gama globulina (g/l

PACS photometry of the Herschel Reference Survey - Far-infrared/sub-millimeter colours as tracers of dust properties in nearby galaxies

We present Herschel/PACS 100 and 160 micron integrated photometry for the 323 galaxies in the Herschel Reference Survey (HRS), a K-band-, volume-limited sample of galaxies in the local Universe. Once combined with the Herschel/SPIRE observations already available, these data make the HRS the largest representative sample of nearby galaxies with homogeneous coverage across the 100-500 micron wavelength range. In this paper, we take advantage of this unique dataset to investigate the properties and shape of the far-infrared/sub-millimeter spectral energy distribution in nearby galaxies. We show that, in the stellar mass range covered by the HRS (8<log(M*/Msun)<12), the far-infrared/sub-millimeter colours are inconsistent with a single modified black-body having the same dust emissivity index beta for all galaxies. In particular, either beta decreases, or multiple temperature components are needed, when moving from metal-rich/gas-poor to metal-poor/gas-rich galaxies. We thus investigate how the dust temperature and mass obtained from a single modified black-body depend on the assumptions made on beta. We show that, while the correlations between dust temperature, galaxy structure and star formation rate are strongly model dependent, the dust mass scaling relations are much more reliable, and variations of beta only change the strength of the observed trends.Comment: 26 pages, 8 figures, 2 tables. Accepted for publication in MNRA

Multiwavelength dissection of a massive heavily dust-obscured galaxy and its blue companion at z∼2

Aims. We study a system of two galaxies, Astarte and Adonis, at z ∼ 2. At this time, the Universe was undergoing the peak of its star formation activity. Astarte is a dusty star-forming galaxy at the massive end of the main sequence (MS), and Adonis is a less massive companion galaxy that is bright in the ultraviolet and has an optical spectroscopic redshift. We investigate whether this ultramassive galaxy is quenching, and whether it has always been on the MS of star-forming galaxies. Methods. We used the code CIGALE to model the spectral energy distribution. The code relies on the energetic balance between the ultraviolet and the infrared. We derived some of the key physical properties of Astarte and Adonis, mainly their star formation rates (SFRs), stellar masses, and dust luminosities. We inspected the variation of the physical parameters depending on the assumed dust-attenuation law. We also estimated the molecular gas mass of Astarte from its CO emission, using different αCO and transition ratios (r31), and we discuss the implication of the various assumptions on the gas-mass derivation. Results. We find that Astarte exhibits a MS-like star formation activity, and Adonis is undergoing a strong starburst phase. The molecular gas mass of Astarte is far lower than the gas fraction of typical star-forming galaxies at z = 2. This low gas content and high SFR result in a depletion time of 0.22 ± 0.07 Gyr, which is slightly shorter than expected for a MS galaxy at this redshift. The CO luminosity relative to the total infrared luminosity suggests a MS-like activity when we assume a galactic conversion factor and a low transition ratio. The SFR of Astarte is on the same order when different attenuation laws are used, unlike its stellar mass, which increases when shallow attenuation laws are used (∼1 × 1011 M⊙ assuming a Calzetti relation, versus ∼4 × 1011 M⊙ assuming a shallow attenuation law). We discuss these properties and suggest that Astarte might be experiencing a recent decrease in star formation activity and is quenching through the MS following a starburst epoch