The Host Galaxies of Fast-Ejecta Core-Collapse Supernovae

Spectra of broad-lined Type Ic supernovae (SN Ic-BL), the only kind of SN observed at the locations of long-duration gamma-ray bursts (LGRBs), exhibit wide features indicative of high ejecta velocities (~0.1c). We study the host galaxies of a sample of 245 low-redshift (z<0.2) core-collapse SN, including 17 SN Ic-BL, discovered by galaxy-untargeted searches, and 15 optically luminous and dust-obscured z<1.2 LGRBs. We show that, in comparison with SDSS galaxies having similar stellar masses, the hosts of low-redshift SN Ic-BL and z<1.2 LGRBs have high stellar-mass and star-formation-rate densities. Core-collapse SN having typical ejecta velocities, in contrast, show no preference for such galaxies. Moreover, we find that the hosts of SN Ic-BL, unlike those of SN Ib/Ic and SN II, exhibit high gas velocity dispersions for their stellar masses. The patterns likely reflect variations among star-forming environments, and suggest that LGRBs can be used as probes of conditions in high-redshift galaxies. They may be caused by efficient formation of massive binary progenitors systems in densely star-forming regions, or, less probably, a higher fraction of stars created with the initial masses required for a SN Ic-BL or LGRB. Finally, we show that the preference of SN Ic-BL and LGRBs for galaxies with high stellar-mass and star-formation-rate densities cannot be attributed to a preference for low metal abundances but must reflect the influence of a separate environmental factor.Comment: Accepted by ApJ 9 May 2014 with only minor revision

Regional Distribution of GHG Emissions from Livestock Enteric Fermentation and Manure Management in the Republic of Macedonia in the Period 2007-2012

The estimation of GHG emission from domestic livestock in the Republic of Macedonia during the period from 2007-2012 is performed according to the IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories applying the Tier 1 method for calculation of emissions. This article has accepted the following gasses: Methane (CH4), Nitrous oxide and CO2-eq from the domestic livestock sub sector using data sources from the official Statistical Yearbooks of the Republic of Macedonia. According to available data for livestock species, distribution of total annual methane emission and nitrogen excretion was calculated in each planning region for the period 2007-2012. In the analyzed period two regions showed continuously highest (Southeast region) and lowest (Vardar region) CH4 emission and nitrogen excretion. In the period 2007-2012 CH4 emission ranged between 26.43 Gg (2007) and 23.78 Gg (2012), with the lowest value in 2012 (23.78 Gg). Depending on the animal waste management system the highest value for nitrogen excretion (solid storage and drylot) was observed in 2010 (kt/N/yr). Almost similar value for nitrogen excretion from pasture and paddock was observed in 2007 and 2008, 9.54 and 9.53 kt/N/yr respectively, with the lowest value for analyzed period noted in 2009 (8.82 kt/N/yr). In this period the highest value (3.32 kt/N/yr) for other type of AWMS was recorded in 2007. Separation of certain regions in the country regarding GHG emission can be clearly noted. Data for the period 2007-2012 show a downward trend in GHG emission. Applications of modern breeding technology, balanced feed as well as better feed quality in the future are the main objectives in order to reduce GHGs emission from this subsector

Galaxies behind the Galactic plane: First results and perspectives from the VVV Survey

Vista Variables in The Via Lactea (VVV) is an ESO variability survey that is performing observations in near infrared bands (ZYJHKs) towards the Galactic bulge and part of the disk with the completeness limits at least 3 mag deeper than 2MASS. In the present work, we searched in the VVV survey data for background galaxies near the Galactic plane using ZYJHKs photometry that covers 1.636 square degrees. We identified 204 new galaxy candidates by analyzing colors, sizes, and visual inspection of multi-band (ZYJHKs) images. The galaxy candidates colors were also compared with the predicted ones by star counts models considering a more realistic extinction model at the same completeness limits observed by VVV. A comparison of the galaxy candidates with the expected one by Milennium simulations is also presented. Our results increase the number density of known galaxies behind the Milky Way by more than one order of magnitude. A catalog with galaxy properties including ellipticity, Petrosian radii and ZYJHKs magnitudes is provided, as well as comparisons of the results with other surveys of galaxies towards Galactic plane.Comment: 27 pages, 10 figures, 2 tables; in press at The Astronomical Journa

The Connection Between Spectral Evolution and GRB Lag

The observed delay in the arrival times between high and low energy photons in gamma-ray bursts (GRBs) has been shown by Norris et al. to be correlated to the absolute luminosity of a GRB. Despite the apparent importance of this spectral lag, there has yet to be a full explanation of its origin. We put forth that the lag is directly due to the evolution of the GRB spectra. In particular, as the energy at which the GRB's $\nu F_{\nu}$ spectra is a maximum ($E_{pk}$) decays through the four BATSE channels, the photon flux peak in each individual channel will inevitably be offset producing what we measure as lag. We test this hypothesis by measuring the rate of $E_{pk}$ decay ($\Phi_{o}$) for a sample of clean single peaked bursts with measured lag. We find a direct correlation between the decay timescale and the spectral lag, demonstrating the relationship between time delay of the low energy photons and the decay of $E_{pk}$. This implies that the luminosity of a GRB is directly related to the burst's rate of spectral evolution, which we believe begins to reveal the underlying physics behind the lag-luminosity correlation. We discuss several possible mechanisms that could cause the observed evolution and its connection to the luminosity of the burst.Comment: 6 pages, 7 figures, submitted to the Astrophysical Journa

Egg Quality Characteristics in Autochthonous Genotypes of Chickens Raised on Macedonian Rural Farms

Egg quality characteristics of three different autochthonous chicken phenotypes (phenotype having ashy-silvery-brown leghorn laced plumage color, phenotype having light brown spangled plumage color and phenotype having black or blue plumage color) were examined. These types of chickens are mainly raised as backyard rural area flocks in the villages of R. Macedonia. The data were collected through first systematic approaches in phenotypical identification and characterisation of these autochthonous genotypes realized recently. Three small flocks of old hens collected from different villages and placed in control pens were established. No data about number of eggs/hen/year is available for the established flocks. Further investigations are needed to record productive (number of egg produced) and reproductive data. The plan was that additional, yearly production records be collected from the flock produced as offspring from established flock of old hens collected from different villages and placed in control pens. Set of 90 eggs was collected (30 eggs from each plumage phenotype) and basic egg quality parameters measured. Egg size (weight) was 50.71g for brown laced plumage phenotype, 60.48g for blue plumage phenotype and 52.6 g for light brown spangled plumage phenotype. Egg shell strength was 3965, 3628 and 3924 g/cm2 for brown laced, blue and brown spangled plumage phenotype, respectively. Light brown spangled plumage phenotype had the highest value of yolk color (10.29) and Hough Units (76.63) compared to brown laced (10.08 and 75.27) and blue (9.09 and 71.65) plumage phenotype

Spatially resolved kinematics in the central 1 kpc of a compact star-forming galaxy at z=2.3 from ALMA CO observations

We present high spatial resolution (FWHM$\sim$0.14'') observations of the CO($8-7$) line in GDS-14876, a compact star-forming galaxy at $z=2.3$ with total stellar mass of $\log(M_{\star}/M_{\odot})=10.9$. The spatially resolved velocity map of the inner $r\lesssim1$~kpc reveals a continous velocity gradient consistent with the kinematics of a rotating disk with $v_{\rm rot}(r=1\rm kpc)=163\pm5$ km s$^{-1}$ and $v_{\rm rot}/\sigma\sim2.5$. The gas-to-stellar ratios estimated from CO($8-7$) and the dust continuum emission span a broad range, $f^{\rm CO}_{\rm gas}=M_{\rm gas}/M_{\star}=13-45\%$ and $f^{\rm cont}_{\rm gas}=50-67\%$, but are nonetheless consistent given the uncertainties in the conversion factors. The dynamical modeling yields a dynamical mass of$\log(M_{\rm dyn}/M_{\odot})=10.58^{+0.5}_{-0.2}$ which is lower, but still consistent with the baryonic mass, $\log$(M$_{\rm bar}$= M$_{\star}$ + M$^{\rm CO}_{\rm gas}$/M$_{\odot}$)$=11.0$, if the smallest CO-based gas fraction is assumed. Despite a low, overall gas fraction, the small physical extent of the dense, star-forming gas probed by CO($8-7$), $\sim3\times$ smaller than the stellar size, implies a strong concentration that increases the gas fraction up to $f^{\rm CO, 1\rm kpc}_{\rm gas}\sim 85\%$ in the central 1 kpc. Such a gas-rich center, coupled with a high star-formation rate, SFR$\sim$ 500 M$_{\odot}$ yr$^{-1}$, suggests that GDS-14876 is quickly assembling a dense stellar component (bulge) in a strong nuclear starburst. Assuming its gas reservoir is depleted without replenishment, GDS-14876 will quickly ($t_{\rm depl}\sim27$ Myr) become a compact quiescent galaxy that could retain some fraction of the observed rotational support.Comment: Accepted for Publication in ApJL. Kinematic maps are shown in Figures 2 and

Analysis of Sub-threshold Short Gamma-ray Bursts in Fermi GBM Data

The Fermi Gamma-ray Burst Monitor (GBM) is currently the most prolific detector of Gamma-Ray Bursts (GRBs). Recently the detection rate of short GRBs (SGRBs) has been dramatically increased through the use of ground-based searches that analyze GBM continuous time tagged event (CTTE) data. Here we examine the efficiency of a method developed to search CTTE data for sub-threshold transient events in temporal coincidence with LIGO/Virgo compact binary coalescence triggers. This targeted search operates by coherently combining data from all 14 GBM detectors by taking into account the complex spatial and energy dependent response of each detector. We use the method to examine a sample of SGRBs that were independently detected by the Burst Alert Telescope on board the Neil Gehrels Swift Observatory, but which were too intrinsically weak or viewed with unfavorable instrument geometry to initiate an on-board trigger of GBM. We find that the search can successfully recover a majority of the BAT detected sample in the CTTE data. We show that the targeted search of CTTE data will be crucial in increasing the GBM sensitivity, and hence the gamma-ray horizon, to weak events such as GRB 170817A. We also examine the properties of the GBM signal possibly associated with the LIGO detection of GW150914 and show that it is consistent with the observed properties of other sub-threshold SGRBs in our sample. We find that the targeted search is capable of recovering true astrophysical signals as weak as the signal associated with GW150914 in the untriggered data.Comment: 10 pages, 9 figures, 1 table, submitted to Ap

The Role of Bulge Formation in the Homogenization of Stellar Populations at z∼2z\sim2 as revealed by Internal Color Dispersion in CANDELS

We use data from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey to study how the spatial variation in the stellar populations of galaxies relate to the formation of galaxies at $1.5 < z < 3.5$. We use the Internal Color Dispersion (ICD), measured between the rest-frame UV and optical bands, which is sensitive to age (and dust attenuation) variations in stellar populations. The ICD shows a relation with the stellar masses and morphologies of the galaxies. Galaxies with the largest variation in their stellar populations as evidenced by high ICD have disk-dominated morphologies (with S\'{e}rsic indexes $< 2$) and stellar masses between $10 < \mathrm{Log~M/ M_\odot}< 11$. There is a marked decrease in the ICD as the stellar mass and/or the S\'ersic index increases. By studying the relations between the ICD and other galaxy properties including sizes, total colors, star-formation rate, and dust attenuation, we conclude that the largest variations in stellar populations occur in galaxies where the light from newly, high star-forming clumps contrasts older stellar disk populations. This phase reaches a peak for galaxies only with a specific stellar mass range, $10 < \mathrm{Log~M/ M_\odot} < 11$, and prior to the formation of a substantial bulge/spheroid. In contrast, galaxies at higher or lower stellar masses, and/or higher S\'{e}rsic index ($n > 2$) show reduced ICD values, implying a greater homogeneity of their stellar populations. This indicates that if a galaxy is to have both a quiescent bulge along with a star forming disk, typical of Hubble Sequence galaxies, this is most common for stellar masses $10 < \mathrm{Log~M/M_\odot} < 11$ and when the bulge component remains relatively small ($n<2$).Comment: 15 pages, 14 figure