ABSTRACT
We present spectra and near-infrared images of a sample of faint radio sources initially selected as promising high-redshift radio galaxy (HzRG) candidates. We have determined redshifts for ...a total of 13 radio galaxies with redshifts ranging from 0.52 ≤ $z$ ≤ 5.72. Our sample probes radio luminosities that are almost an order of magnitude fainter than previous large samples at the highest redshifts. We use near-infrared photometry for a subsample of these galaxies to calculate stellar masses using simple stellar population models, and find stellar masses to be in the range $10^{10.8} {--}10^{11.7} \, \mathrm{M}_\odot$. We then compare our faint radio galaxies with brighter radio galaxies at $z$ ≥ 2 from the literature. We find that fainter radio galaxies have lower Ly α luminosities and narrower line widths compared to the bright ones, implying photoionization by a weaker active galactic nucleus (AGN). We also rule out the presence of strong shocks in faint HzRGs. The stellar masses determined for faint HzRGs are lower than those observed for brighter ones. We find that faint HzRG population in the redshift range 2–4 forms a bridge between star-forming and narrow-line AGNs, whereas the ones at $z$ > 4 are likely to be dominated by star formation, and may be building up their stellar mass through cold accretion of gas. Finally, we show that the overall redshift evolution of radio sizes at $z$ > 2 is fully compatible with increased inverse Compton scattering losses at high redshifts.
We present a detailed kinematical and dynamical study of the galaxy cluster RXCJ1111.6+4050 (RXCJ1111), at
z
= 0.0756 using 104 new spectroscopic redshifts of galaxies observed at the Telescopio ...Nazionale
Galileo
and SDSS DR16 public archive. Our analysis is performed in a multiwavelength context in order to study and compare mainly optical and X-ray properties using
XMM-Newton
data. We find that RXCJ1111 is a galaxy cluster showing a velocity distribution with clear deviations from Gaussianity, that we are able to explain by the presence of a substructure within the cluster. The two cluster components show velocity dispersions of 644 ± 56 km s
−1
and 410 ± 123 km s
−1
, which yield dynamical masses of
M
200
= 1.9 ± 0.4 × 10
14
M
⊙
and 0.6 ± 0.4 × 10
14
M
⊙
for the main system and substructure, respectively. The 2D spatial distribution of galaxies and X-ray surface brightness of RXCJ1111 presents an elongation in the North–South direction. These observational facts, together with a gradient of 250−350 km s
−1
Mpc
−1
in the velocity field, following the NNE–SSE direction, suggest that the merger axis between the main system and substructure is slightly tilted with respect to the line-of-sight. The substructure is characterized by a magnitude gap Δ
m
12
≥ 1.8, so it fits the “fossil-like” definition of a galaxy group. From the X-ray observations, we estimate a
M
500, X
= 1.68 ± 0.25 × 10
14
M
⊙
, which is in good agreement with the dynamical masses when two galaxy components are considered separately. This suggests that the mass estimates obtained from X-ray and velocity dispersion are compatible even for non-relaxed clusters, at least when we are able to identify and separate galaxy clumps and derive masses by considering the virialized regions. We propose a 3D merging model and find that the fossil group is in an early phase of collision with the RXCJ1111 main cluster and placed at ∼8° ( ± 3° ) from line-of-sight. This merging model would explain the slight increase found in the
T
X
with respect to what we would expect for relaxed clusters. Due to the presence of several brightest galaxies, after this collision, the substructure would presumably lose its fossil condition. Therefore, RXCJ1111 represents the observational evidence that the fossil stage of a system can be temporary and transitional.
Solid-state fermentation (SSF), a process that occurs in the absence or near absence of water, has been used for the production of various high value added products such as enzymes and other organic ...components. This paper reviews the recent studies reported on the use of SSF for the production of enzymes: lipases, proteases, cellulases, hemicellulases, ligninases, glucoamylases, pectinases, and inulinases. The microorganisms used for fermentation are mostly fungi, and substrates are waste materials from the agriculture and food industry. This shows the advantages of SSF from an economical and environmental viewpoint. The paper provides an update on several issues, viz. wastes, microorganisms, and issues of scaling up and controlling the process of fermentation in solid state.
We study the structure of the galaxy cluster Abell 523 (A523) at z = 0.104 using new spectroscopic data for 132 galaxies acquired at the Telescopio Nazionale Galileo, new photometric data from the ...Isaac Newton Telescope, and X-ray and radio data from the Chandra and Very Large Array archives. We estimate the velocity dispersion of the galaxy population, ..., and the X-ray temperature of the hot intracluster medium, kT = 5.3 plus or minus 0.3 keV. We infer that A523 is a massive system: M sub( 200) ~ 7-9 x 10 super( 14) M... The analysis of the optical data confirms the presence of two subclusters, 0.75 Mpc apart, tracing the SSW-NNE direction and dominated by the two brightest cluster galaxies (BCG1 and BCG2). The X-ray surface brightness is strongly elongated towards the NNE direction, and its peak is clearly offset from both the brightest cluster galaxies (BCGs). We confirm the presence of a 1.3 Mpc large radio halo, elongated in the ESE-WNW direction and perpendicular to the optical/X-ray elongation. We detect a significant radio/X-ray offset and radio polarization, two features which might be the result of a magnetic field energy spread on large spatial scales. A523 is found consistent with most scaling relations followed by clusters hosting radio haloes, but quite peculiar in the P sub( radio)-L sub( x )relation: it is underluminous in the X-rays or overluminous in radio. A523 can be described as a binary head-on merger caught after a collision along the SSW-NNE direction. However, minor optical and radio features suggest a more complex cluster structure, with A523 forming at the crossing of two filaments along the SSW-NNE and ESE-WNW directions. (ProQuest: ... denotes formulae/symbols omitted.)
The second catalogue of Planck Sunyaev-Zeldovich (SZ) sources, hereafter PSZ2, represents the largest galaxy cluster sample selected by means of their SZ signature in a full-sky survey. Using ...telescopes at the Canary Island observatories, we conducted the long-term observational program 128- MULTIPLE-16/15B (hereafter LP15), a large and complete optical follow-up campaign of all the unidentified PSZ2 sources in the northern sky, with declinations above −15° and no correspondence in the first Planck catalogue PSZ1. This paper is the third and last in the series of LP15 results, after Streblyanska et al. (2019, A&A, 628, A13) and Aguado-Barahona et al. (2019, A&A, 631, A148), and presents all the spectroscopic observations of the full program. We complement these LP15 spectroscopic results with Sloan Digital Sky Survey archival data and other observations from a previous program (ITP13-08), and present a catalogue of 388 clusters and groups of galaxies including estimates of their velocity dispersion. The majority of them (356) are optical counterparts of PSZ2 sources. A subset of 297 of those clusters are used to construct the MSZ − Mdyn scaling relation based on the estimated SZ mass from Planck measurements and our dynamical mass estimates. We discuss and correct for different statistical and physical biases in the estimation of the masses, such as the Eddington bias when estimating MSZ and the aperture and the number of galaxies used to calculate Mdyn. The SZ-to-dynamical mass ratio for those 297 PSZ2 clusters is (1 − B) = 0.80 ± 0.04 (stat) ± 0.05 (sys), with only marginal evidence for a possible mass dependence for this factor. Our value is consistent with previous results in the literature, but is associated with a significantly smaller uncertainty due to the use of the largest sample size for this type of study.
We study the dynamical status of the galaxy system ZwCl 2341.1+0000, a filamentary multi-Mpc galaxy structure associated with a complex diffuse radio emission.
Our analysis is mainly based on new ...spectroscopic data for 128 galaxies acquired at the Italian Telescopio Nazionale Galileo. We also use optical data available in the Sloan Digital Sky Survey and X-ray data from the Chandra archive.
We select 101 cluster member galaxies and compute the cluster redshift 〈z〉 ∼ 0.2693 and the global line-of-sight velocity dispersion σ
V
∼ 1000 km s−1.
Our optical analysis agrees with the presence of at least three, likely four or more, optical subclusters causing the south-south-east-north-north-west (SSE-NNW) elongation of the galaxy distribution and a significant velocity gradient in the south-north direction. In particular, we detect an important low-velocity subclump in the southern region, roughly coincident with the brightest peak of the diffuse radio emission but with a clear offset between the optical and radio peaks. We also detect one (or two) optical subcluster(s) at north, in correspondence with the second brightest radio emission, and another one in the central cluster region, where a third diffuse radio source has been recently detected. A more refined analysis involving the study of the 2D galaxy distribution suggests an even more complex structure. Depending on the adopted model, we obtain a mass estimate M
sys ∼ 1-3
for the whole system.
As for the X-ray analysis, we confirm the SSE-NNW elongation of the intracluster medium and detect four significant peaks. The X-ray emission is strongly asymmetric and offsetted with respect to the galaxy distribution, thus suggesting a merger caught in the phase of post-core-core passage.
Our findings support two possible hypotheses for the nature of the diffuse radio emission of ZwCl 2341.1+0000: a two relics + halo scenario or diffuse emission associated with the infall and merging of several galaxy groups during the first phase of the cluster formation.
It has been posited that lunar eclipse observations may help predict the in-transit signature of Earth-like extrasolar planets. However, a comparative analysis of the two phenomena addressing in ...detail the transport of stellar light through the planet's atmosphere has not yet been presented. Here, we proceed with the investigation of both phenomena by making use of a common formulation. Our starting point is a set of previously unpublished near-infrared spectra collected at various phases during the 2008 August lunar eclipse. We then take the formulation to the limit of an infinitely distant observer in order to investigate the in-transit signature of the Earth-Sun system as being observed from outside our solar system. The refraction bending of sunlight rays that pass through Earth's atmosphere is a critical factor in the illumination of the eclipsed Moon. Likewise, refraction will have an impact on the in-transit transmission spectrum for specific planet-star systems depending on the refractive properties of the planet's atmosphere, the stellar size, and the planet's orbital distance. For the Earth-Sun system, at mid-transit, refraction prevents the remote observer's access to the lower ~12-14 km of the atmosphere and, thus, also to the bulk of the spectroscopically active atmospheric gases. We demonstrate that the effective optical radius of the Earth in-transit is modulated by refraction and varies by ~12 km from mid-transit to internal contact. The refractive nature of atmospheres, a property which is rarely accounted for in published investigations, will pose additional challenges to the characterization of Earth-like extrasolar planets. Refraction may have a lesser impact for Earth-like extrasolar planets within the habitable zone of some M-type stars.
We present a new deep spectroscopic catalogue for Abell 85, within 3.0 × 2.6 Mpc2 and down to
$M_{r} \sim M_{r}^{\ast } +6$
. Using the Visible Multi-Object Spectrograph at the Very Large Telescope ...and the AutoFiber 2 at the William Herschel Telescope, we obtained almost 1430 new redshifts for galaxies with m
r
≤ 21 mag and 〈μ
e,r
〉 ≤ 24 mag arcsec−2. These redshifts, together with Sloan Digital Sky Survey Data Release 6 and NASA/IPAC Extragaalctic Database spectroscopic information, result in 460 confirmed cluster members. This data set allows the study of the luminosity function (LF) of the cluster galaxies covering three orders of magnitudes in luminosities. The total and radial LFs are best modelled by a double Schechter function. The normalized LFs show that their bright (M
r
≤ −21.5) and faint (M
r
≥ −18.0) ends are independent of clustercentric distance and similar to the field LFs unlike the intermediate luminosity range (−21.5 ≤ M
r
≤ −18.0). Similar results are found for the LFs of the dominant types of galaxies: red, passive, virialized and early-infall members. On the contrary, the LFs of blue, star forming, non-virialized and recent-infall galaxies are well described by a single Schechter function. These populations contribute to a small fraction of the galaxy density in the innermost cluster region. However, in the outskirts of the cluster, they have similar densities to red, passive, virialized and early-infall members at the LF faint end. These results confirm a clear dependence of the colour and star formation of Abell 85 members in the cluster centric distance.
•On-site and laboratory stability, maturity tests were performed on 2 compost piles.•Some on-site tests were not consistent with the findings at laboratory scale.•Stability was detected in some ...samples that were, however, immature.•No strong correlations were found between stability and maturity indices.
Stability and maturity are important criteria to guarantee the quality of a compost that is applied to agriculture or used as amendment in degraded soils. Although different techniques exist to evaluate stability and maturity, the application of laboratory tests in municipalities in developing countries can be limited due to cost and application complexities. In the composting facilities of such places, some classical low cost on-site tests to monitor the composting process are usually implemented; however, such tests do not necessarily clearly identify conditions of stability and maturity. In this article, we have applied and compared results of stability and maturity tests that can be easily employed on site (i.e. temperature, pH, moisture, electrical conductivity EC, odor and color), and of tests that require more complex laboratory techniques (volatile solids, C/N ratio, self-heating, respirometric index, germination index GI). The evaluation of the above was performed in the field scale using 2 piles of biowaste applied compost. The monitoring period was from day 70 to day 190 of the process. Results showed that the low-cost tests traditionally employed to monitor the composting process on-site, such as temperature, color and moisture, do not provide consistent determinations with the more complex laboratory tests used to assess stability (e.g. respiration index, self-heating, volatile solids). In the case of maturity tests (GI, pH, EC), both the on-site tests (pH, EC) and the laboratory test (GI) provided consistent results. Although, stability was indicated for most of the samples, the maturity tests indicated that products were consistently immature. Thus, a stable product is not necessarily mature. Conclusively, the decision on the quality of the compost in the installations located in developing countries requires the simultaneous use of a combination of tests that are performed both in the laboratory and on-site.
Context. The mechanisms producing the diffuse radio emission in galaxy clusters, and in particular their connection with cluster mergers, are still debated. Aims. We seek to explore the internal ...dynamics of the cluster Abell 1758N, which has been shown to host a radio halo and two relics, and is known to be a merging bimodal cluster. Methods. Our analysis is mainly based on new redshift data for 137 galaxies acquired at the Telescopio Nazionale Galileo, only four of which have redshifts previously listed in the literature. We also used photometric data from the Sloan Digital Sky Survey and from the Canada-France-Hawaii Telescope archive. We combined galaxy velocities and positions to select 92 cluster galaxies and analyzed the internal cluster dynamics. Results. We estimate a cluster redshift of ⟨z⟩ = 0.2782 and quite a high line-of-sight (LOS) velocity dispersion σV ~ 1300 km s-1. Our 2D analysis confirms the presence of a bimodal structure along the NW–SE direction. We add several pieces of information to the previous merging scenario: the two subclusters (here A1758N(NW) and A1758N(SE)) cannot be separated in the velocity analyses and we deduce a small LOS velocity difference (ΔVrf,LOS ≲ 300 km s-1 in the cluster rest-frame). The velocity information successfully shows that A1758N is surrounded by two small groups and active galaxies infalling onto, or escaping from, the cluster. Removing the two groups, we estimate σV,NW ~ 1000 km s-1 and σV,SE ~ 800 km s-1 for A1758N(NW) and A1758N(SE), respectively. We find that Abell 1758N is a very massive cluster with a range of M = 2−3 × 1015 h70-1 M⊙, depending on the adopted model. Conclusions. As expected for clusters that host powerful, extended, diffuse radio emissions, Abell 1758N is a major cluster merger just forming a massive system.
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