Fermi-Dirac statistics plus liquid description of quark partons

A previous approach with Fermi-Dirac distributions for fermion partons is here improved to comply with the expected low $x$ behaviour of structure functions. We are so able to get a fair description of the unpolarized and polarized structure functions of the nucleons as well as of neutrino data. We cannot reach definite conclusions, but confirm our suspicion of a relationship between the defects in Gottfried and spin sum rules.Comment: 15 pages, plain LaTex, 10 compressed tarred uuencoded figures in a separate fil

The MURALES survey: III. Completing the MUSE observations of 37 3C low-z radio galaxies

Galaxie

The MURALES survey: V. Jet-induced star formation in 3C 277.3 (Coma A)

Interstellar matter and star formatio

Polarization observables in the reaction NN→NNΦNN \to NN \Phi

We study the reaction $NN \to NN \Phi$ slightly above the threshold within an extended one-boson exchange model which also accounts for $uud$ knock-out. It is shown that polarization observables, like the beam-target asymmetry, are sensible quantities for identifying a $s \bar s$ admixture in the nucleon wave function on the few per cent level.Comment: 11 LaTeX pages including 4 ps figure

Accretion mode versus radio morphology in the LOFAR Deep Fields

Galaxie

Raining in MKW 3 s: a Chandra-MUSE analysis of X-Ray cold filaments around 3CR 318.1

High Energy Astrophysic

LeMMINGs – I. The eMERLIN legacy survey of nearby galaxies. 1.5-GHz parsec-scale radio structures and cores

Artículo escrito por 32 autoresWe present the first data release of high-resolution (≤0.2 arcsec) 1.5-GHz radio images of 103 nearby galaxies from the Palomar sample, observed with the eMERLIN array, as part of the LeMMINGs survey. This sample includes galaxies which are active (low-ionization nuclear emission-line regions [LINER] and Seyfert) and quiescent (H II galaxies and absorption line galaxies, ALGs), which are reclassified based upon revised emission-line diagrams. We detect radio emission ≳0.2 mJy for 47/103 galaxies (22/34 for LINERS, 4/4 for Seyferts, 16/51 for H II galaxies, and 5/14 for ALGs) with radio sizes typically of ≲100 pc. We identify the radio core position within the radio structures for 41 sources. Half of the sample shows jetted morphologies. The remaining half shows single radio cores or complex morphologies. LINERs show radio structures more core-brightened than Seyferts. Radio luminosities of the sample range from 1032 to 1040 erg s−1: LINERs and H II galaxies show the highest and lowest radio powers, respectively, while ALGs and Seyferts have intermediate luminosities. We find that radio core luminosities correlate with black hole (BH) mass down to ∼107 M⊙, but a break emerges at lower masses. Using [O III] line luminosity as a proxy for the accretion luminosity, active nuclei and jetted H II galaxies follow an optical Fundamental Plane of BH activity, suggesting a common disc–jet relationship. In conclusion, LINER nuclei are the scaled-down version of FR I radio galaxies; Seyferts show less collimated jets; H II galaxies may host weak active BHs and/or nuclear star-forming cores; and recurrent BH activity may account for ALG properties.UK Research & InnovationScience & Technology Facilities CouncilRoyal SocietyUniversity of SouthamptonEuropean UnionGobierno de EspañaMinisterio de Economía y CompetitividadSpanish postdoctoral fellowship 'Ayudas para la atraccion del talento investigador. Modalidad 2: jovenes investigadores, financiadas por la Comunidad de Madrid'Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasInstituto de Física de Partículas y del Cosmos (IPARCOS)TRUEpu

The low-frequency properties of FR 0 radio galaxies

Using the alternative data release of the TIFR GMRT Sky Survey (TGSS), we studied the low-frequency properties of FR 0 radio galaxies, the large population of compact radio sources associated with red massive early-type galaxies revealed by surveys at 1.4 GHz. We considered TGSS observations from FR0CAT, a sample formed by 104 FR 0s at z\u2004 < \u2004 0.05: all but one of them are covered by the TGSS, and 43 of them are detected above a 5\u3c3 limit of 17.5 mJy. No extended emission has been detected around the FR 0s, corresponding to a luminosity limit of 72 4\u2005 7\u2005 1023 W Hz-1 over an area of 100 kpc 7 100 kpc. All but eight FR 0s have a flat or inverted spectral shape (\u3b1\u2004 < \u2004 0.5) between 150 MHz and 1.4 GHz: this spectral behavior confirms the general paucity of optically thin extended emission within the TGSS beam, as is expected for their compact 1.4 GHz morphology. Data at 5 GHz were used to build their radio spectra, which are also generally flat at higher frequencies. By focusing on a sub-sample of FR 0s with flux density > 50 mJy at 1.4 GHz, we found that 3c75% of them have a convex spectrum, but with a smaller curvature than the more powerful gigahertz peaked-spectrum sources (GPS). The typical FR 0s radio spectrum is better described by a gradual steepening toward high frequencies, rather than to a transition from an optically-thick to an optically-thin regime, possibly observed in only 3c15% of the sample

Hard-X-ray-selected active galactic nuclei - I. A radio view at high frequencies

A thorough study of radio emission in Active Galactic Nuclei (AGN) is of fundamental importance to understand the physical mechanisms responsible for the emission and the interplay between accretion and ejection processes. High frequency radio observations can target the nuclear contribution of smaller emitting regions and areless affected by absorption. We present JVLA 22 and 45 GHz observations of 16 nearby (0.003≤z≤0.3) hard - X-rays selected AGN at the (sub)-kpc scale with tens μJy beam−1 sensitivity. We detected 15/16 sources, with flux densities ranging from hundreds μJy to tens Jy (specific luminosities from ∼1020 to ∼1025W Hz−1at 22 GHz). All detected sources host a compact core, with 8 being core-dominated at either frequencies, the others exhibiting also extended structures. Spectral indices range from steep to flat/inverted. We interpret this evidence as either due to a core+jet system (6/15), a core accompanied by surrounding star formation (1/15), to a jet oriented close to the line of sight (3/15), to emission from a corona or the base of a jet (1/15), although there might be degeneracies between different processes. Four sources require more data to shed light on their nature. We conclude that, at these frequencies, extended, optically-thin components are present together with the flat-spectrum core. The LR/LX ∼ 10−5 relation is roughly followed, indicating a possible contribution to radio emission from a hot corona. A weakly significant correlation between radio core (22 and 45 GHz) and X-rays luminosities is discussed in the light of an accretion-ejection framework