1,073 research outputs found
The ATESP 5 GHz radio survey IV. 19, 38, and 94 GHz observations and radio spectral energy distributions
It is now established that the faint radio population is a mixture of
star-forming galaxies and faint active galactic nuclei (AGNs), with the former
dominating below S(1.4GHz) \sim 100 muJy and the latter at larger flux
densities. The faint radio AGN component can itself be separated into two main
classes, mainly based on the host-galaxy properties: sources associated with
red/early-type galaxies (like radio galaxies) are the dominant class down to
\sim 100 muJy; quasar/Seyfert--like sources contribute an additional 10-20\%.
One of the major open questions regarding faint radio AGNs is the physical
process responsible for their radio emission. This work aims at investigating
this issue, with particular respect to the AGN component associated with
red/early-type galaxies. Such AGNs show, on average, flatter radio spectra than
radio galaxies and are mostly compact (<= 30 kpc in size). Various scenarios
have been proposed to explain their radio emission. For instance they could be
core/core-jet dominated radio galaxies, low-power BL LACs, or
advection-dominated accretion flow (ADAF) systems. We used the Australia
Telescope Compact Array (ATCA) to extend a previous follow-up multi-frequency
campaign to 38 and 94 GHz. (abridged)Comment: 16 pages, 7 figures, 6 tables. Accepted for publication in A&
Pengembangan Model Penguatan Lembaga Pertanian sebagai Prime Mover Pembangunan Kawasan Daerah Penyangga Pembangunan (Dpp) Destinasi Wisata Kintamani Bali
Tujuan pokok penelitian ini mengembangkan model prime mover sektor pertanian argo di daerah penyangga pembangunan (DPP) destinasi wisata Kintamani untuk penguatan dan pemberdayaan para petani agro berbasis kewilayahan dan berbasis penguatan kelembagaan lokal di Kecamatan Kintamani Kabupaten Bangli. Penelitian ini menggunakan desain penelitian dan pengembangan (R&D) dengan metode kuantitatif IG (Indeks Gravitasi) untuk melihat derajat keterkaitan aktivitas ekonomi antara DPP dan desa sekitarnya, CDSF (Cobb-Douglas Stochastic Frontier) untuk melihat tingkat efisiensi teknis yang mencerminkan sejauhmana kegiatan produksi sektor dominan di DPP mencapai titik optimumnya, serta metode EL (Ekonometrik Logit) untuk mengetahui adakah fragmentasi produksi DPP dengan desa sekitarnya. Dalam penyusunan desain pola pengembangan ekonomi di DPP mengacu pada temuan studi pendahuluan dan trending analysis terkait dengan keunggulan potensi, permasalahan yang paling urgen, dan peluang usaha di masing-masing wilayah. Produk penelitian ini adalah : (1) peta permasalahan dan produksi dominan petani agro, (2) peta kelembagaan petani agro, (3) model pelembagaan petani agro, (4) draft model prime mover sektor pertanian agro terhadap pengembangan destinasi wisata, dan (5) artikel ilmiah (jurnal terakreditasi). Hasil penelitian menunjukkan bahwa : (1) berdasarkan data Dinas Pariwisata Kabupaten Bangli Provinsi Bali, yaitu : Desa Batur Selatan, desa Songan A, desa Songan B,dan desa Kedisan. Secara umum lembaga-lembaga social kemasyarakatan yang ada di semua desa tersebut hamper sama,hanya struktur organisasinya yang sedikit berbeda, yang disesuaikan dengan kebutuhan dan kebiasaan masyarakat setempat. (2) lembaga social dan budaya yang terdapat di desa-desa kawasan agrowisata Kintamani, pada umumnya adalah : sekehe teruna teruni, kelompok tani, gabungan kelompok tani, sekehe jogged, sekehe santi, sekehe tabuh, sekehe payus, sekehe rejang,sekehe manyi, sekehe baris, sekehe pruguh, sekehe gong, sekehe gambuh, lembaga perkreditan desa, desa adat, prajuru desa adat, koperasi unti desa,kelompok penyakap,dan kelompok peternak. (3) pada desa-desa kawasan agrowisata di Kintamani, terdapat lahan yang masih cukup besar untuk dimaksimalkan pemanfaatannya, yakni berkisar antara 10 sampai 100 hektar di setiap desanya. Namun, berdasarkan hasil survey di lapangan, hanya sebagian kecil dari lahan tersebut yang merupakan milik penduduk setempat. (4) potensi kawasan Kintamani pada dasarnya bersandar pada keindahan alam dan modalitas social budaya masyarakat itu sendiri. (5) masih ditemukan berbagai kendala yang dihadapi oleh masyarakat desa kawasan agrowisata pada umumnya dan petani pada khusnya, terutama pada aspek-aspek khusus, seperti: aturan desa dan pengelolaan lembaga sosial dan budaya desa, luas dan kepemilikan lahan, system permodalan, pemanfaatan sumber daya, dan system penjualan
Dumb-bell galaxies in southern clusters: Catalog and preliminary statistical results
The dominant galaxy of a rich cluster is often an object whose formation and evolution is closely connected to the dynamics of the cluster itself. Hoessel (1980) and Schneider et al. (1983) estimate that 50 percent of the dominant galaxies are either of the dumb-bell type or have companions at projected distances less than 20 kpc, which is far in excess of the number expected from chance projection (see also Rood and Leir 1979). Presently there is no complete sample of these objects, with the exception of the listing of dumb-bell galaxies in BM type I and I-II clusters in the Abell statistical sample of Rood and Leir (1979). Recent dynamical studies of dumb-bell galaxies in clusters (Valentijn and Casertano, 1988) still suffer from inhomogeneity of the sample. The fact that it is a mixture of optically and radio selected objects may have introduced an unknown biases, for instance if the probability of radio emission is enhanced by the presence of close companions (Stocke, 1978, Heckman et al. 1985, Vettolani and Gregorini 1988) a bias could be present in their velocity distribution. However, this situation is bound to improve: a new sample of Abell clusters in the Southern Hemisphere has been constructed (Abell et al., 1988 hereafter ACO), which has several advantages over the original northern catalog. The plate material (IIIaJ plates) is of better quality and reaches fainter magnitudes. This makes it possible to classify the cluster types with a higher degree of accuracy, as well as to fainter magnitudes. The authors therefore decided to reconsider the whole problem constructing a new sample of dumb-bell galaxies homogeneously selected from the ACO survey. Details of the classification criteria are given
Identification of Some Errors in the Genome Assembly of Bovidae by FISH
From an economic point of view, Bovidae represent the most important family of the Ruminantia suborder. Thus, the mitochondrial and nuclear genomes of Bos taurus were among the first genomes to be sequenced after the sequencing of the human genomes. Over the millennia, the evolution of the genomes of the 3 main species belonging to the Bovidae family - B. taurus (BTA), Ovis aries (OAR), and Capra hircus (CHI) - has led to few chromosome rearrangements. Certainly, the availability and free access to the animal genomes significantly contributed to the improvement of animal genetics; however, some errors may exist due to the high automation in the genomic assembly construction process. In this work, some differences between the genomes of cattle, goat, and sheep highlighted by bioinformatics analysis have been verified by FISH, confirming that some errors persist even in the most recent genome assemblies. This type of approach has allowed us to detect a misassembly of a region belonging to BTA16 and to the homologues OAR12 and CHI16, a misassembly of a short tract in BTA22, OAR19, and CHI22, an incorrect mapping of a region of BTA21 and of CHI27 and OAR26, a discrepancy in the BTA26, OAR22, and CHI26 assemblies, a missed inversion in CHI1 compared to BTA1 and OAR1, and the exact assembly of a region of about 7 Mb in OAR10 and CHI12. Incorrect positioning of genomic tracts can cause unintended consequences in genetic analyses, especially when the data represent a starting point for the construction of genetic tools. In the new genomic assemblies published after the conclusion of our experiments, however, the accuracy in the construction of animal assemblies has been much improved, even if the new assemblies present more extended unmapped portions than the previous versions. The gap could be filled by comparative analyses between similar species or FISH
Structure of the magnetoionic medium around the FR Class I radio galaxy 3C 449
The goal of this work is to constrain the strength and structure of the
magnetic field associated with the environment of the radio source 3C 449,
using observations of Faraday rotation, which we model with a structure
function technique and by comparison with numerical simulations. We assume that
the magnetic field is a Gaussian, isotropic random variable and that it is
embedded in the hot intra-group plasma surrounding the radio source. For this
purpose, we present detailed rotation measure images for the polarized radio
source 3C 449, previously observed with the Very Large Array at seven
frequencies between 1.365 and 8.385 GHz. We quantify the statistics of the
magnetic-field fluctuations by deriving rotation measure structure functions,
which we fit using models derived from theoretical power spectra. We quantify
the errors due to sampling by making multiple two-dimensional realizations of
the best-fitting power spectrum.We also use depolarization measurements to
estimate the minimum scale of the field variations. We then make
three-dimensional models with a gas density distribution derived from X-ray
observations and a random magnetic field with this power spectrum. Under these
assumptions we find that both rotation measure and depolarization data are
consistent with a broken power-law magnetic-field power spectrum, with a break
at about 11 kpc and slopes of 2.98 and 2.07 at smaller and larger scales
respectively. The maximum and minimum scales of the fluctuations are around 65
and 0.2 kpc, respectively. The average magnetic field strength at the cluster
centre is 3.5 +/-1.2 micro-G, decreasing linearly with the gas density within
about 16 kpc of the nucleus.Comment: 19 pages; 14 figures; accepted for publication on A&A. For a high
quality version use ftp://ftp.eso.org/pub/general/guidetti
Large Merger Recoils and Spin Flips From Generic Black-Hole Binaries
We report the first results from evolutions of a generic black-hole binary,
i.e. a binary containing unequal mass black holes with misaligned spins. Our
configuration, which has a mass ratio of 2:1, consists of an initially
non-spinning hole orbiting a larger, rapidly spinning hole (specific spin a/m =
0.885), with the spin direction oriented -45 degrees with respect to the
orbital plane. We track the inspiral and merger for ~2 orbits and find that the
remnant receives a substantial kick of 454 km/s, more than twice as large as
the maximum kick from non-spinning binaries. The remnant spin direction is
flipped by 103 degrees with respect to the initial spin direction of the larger
hole. We performed a second run with anti-aligned spins, a/m = +-0.5 lying in
the orbital plane that produces a kick of 1830 km/s off the orbital plane. This
value scales to nearly 4000 km/s for maximally spinning holes. Such a large
recoil velocity opens the possibility that a merged binary can be ejected even
from the nucleus of a massive host galaxy.Comment: 4 pages. Accepted for publication in ApJ
Jet triggered Type Ia supernovae in radio-galaxies?
We report the serendipitous discovery of a supernova (SN) in the nearby
radio-galaxy 3C 78. Observations obtained with the STIS spectrograph on board
the Hubble Space Telescope show, at a distance of 0.54 arcsec (300 pc) from the
galaxy nucleus, a second bright source, not present in previous images. As this
source was fortuitously covered by the spectrograph slit its spectrum was
obtained and it is characteristic of a Type Ia SN. This SN is closely aligned
with the radio-jet of 3C 78. Analysis of historical records shows that such a
close association between jet and supernova occurred in 6 of the 14 reported
SNe in radio-galaxies. The probability that this results from a random
distribution of SN in the host galaxy is less than 0.05%. We then argue that
jets might trigger supernova explosions.Comment: 9 pages, 3 figures, 1 table, to appear in ApJL, 20 Jul 200
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