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result(s) for
"Maiorano, Elisabetta"
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Metamorphosis of Supernova SN 2008D/XRF 080109: A Link Between Supernovae and GRBs/Hypernovae
by
Nomoto, Ken'ichi
,
D'Elia, Valerio
,
D'Avanzo, Paolo
in
Astronomy
,
Black holes
,
Earth, ocean, space
2008
The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E [almost equal to] 6x10⁵¹ erg) and ejected mass [~7 times the mass of the Sun ([Formula: see text])] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a ~30 [Formula: see text] star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.
Journal Article
GRB 211024B: an ultra-long GRB powered by magnetar
2024
Ultra-long gamma-ray bursts (ULGRBs) are characterized by exceptionally long-duration central engine activities, with characteristic timescales exceeding 1000 seconds. We present ground-based optical afterglow observations of the ultra-long gamma-ray burst GRB 211024B, detected by \\textit{Swift}. Its X-ray light curve exhibits a characteristic ``internal plateau\" with a shallow decay phase lasting approximately \\(\\sim 15\\) ks, followed by a steep decline (\\(\\alpha_{\\rm drop}\\sim-7.5\\)). Moreover, the early optical emission predicted by the late r-band optical afterglow is significantly higher than the observed value, indicating an external shock with energy injection. To explain these observations, we propose a magnetar central engine model. The magnetar collapse into a black hole due to spin-down or hyperaccretion, leading to the observed steep break in the X-ray light curve. The afterglow model fitting reveals that the afterglow injection luminosity varies with different assumptions of the circumburst medium density, implying different potential energy sources. For the interstellar medium (ISM) case with a fixed injection end time, the energy may originate from the magnetar's dipole radiation. However, in other scenarios, relativistic jets produced by the magnetar/black hole system could be the primary energy source.
Large-scale retrospective relative spectro-photometric self-calibration in space
2017
We consider the application of relative self-calibration using overlap regions to spectroscopic galaxy surveys that use slit-less spectroscopy. This method is based on that developed for the SDSS by Padmanabhan at al. (2008) in that we consider jointly fitting and marginalising over calibrator brightness, rather than treating these as free parameters. However, we separate the calibration of the detector-to-detector from the full-focal-plane exposure-to-exposure calibration. To demonstrate how the calibration procedure will work, we simulate the procedure for a potential implementation of the spectroscopic component of the wide Euclid survey. We study the change of coverage and the determination of relative multiplicative errors in flux measurements for different dithering configurations. We use the new method to study the case where the flat-field across each exposure or detector is measured precisely and only exposure-to-exposure or detector-to-detector variation in the flux error remains. We consider several base dither patterns and find that they strongly influence the ability to calibrate, using this methodology. To enable self-calibration, it is important that the survey strategy connects different observations with at least a minimum amount of overlap, and we propose an \"S\"-pattern for dithering that fulfills this requirement. The final survey strategy adopted by Euclid will have to optimise for a number of different science goals and requirements. The large-scale calibration of the spectroscopic galaxy survey is clearly cosmologically crucial, but is not the only one.
GRB 060605: multi-wavelength analysis of the first GRB observed using integral field spectroscopy
by
Kann, David Alexander
,
Greiner, Jochen
,
Amati, Lorenzo
in
Collimation
,
Galaxies
,
Gamma ray astronomy
2009
The long and relatively faint gamma-ray burst GRB 060605 detected by \\emph{Swift}/BAT lasted about 20 sec. Its afterglow could be observed with \\emph{Swift}/XRT for nearly 1 day, while \\emph{Swift}/UVOT could detect the afterglow during the first 6 hours after the event. Here, we report on integral field spectroscopy of its afterglow performed with PMAS/PPak mounted at the Calar Alto 3.5 m telescope. In addition, we report on a detailed analysis of XRT and UVOT data and on the results of deep late-time VLT observations that reveal the GRB host galaxy. We find that the burst occurred at a redshift of \\(z\\)=3.773, possibly associated with a faint, \\(R_C=26.4 \\pm 0.3\\) host. Based on the optical and X-ray data, we deduce information on the SED of the afterglow, the position of the cooling frequency in the SED, the nature of the circumburst environment, its collimation factor, and its energetics. We find that the GRB fireball was expanding into a constant-density medium and that the explosion was collimated with a narrow half-opening angle of about 2.4 degrees. The initial Lorentz factor of the fireball was about 250; however, its beaming-corrected energy release in the gamma-ray band was comparably low. The optical, X-ray afterglow, on the other hand, was rather luminous. Finally, we find that the data are consistent within the error bars with an achromatic evolution of the afterglow during the suspected jet break time at about 0.27 days after the burst.
The metamorphosis of Supernova SN2008D/XRF080109: a link between Supernovae and GRBs/Hypernovae
2008
The only supernovae (SNe) to have shown early gamma-ray or X-ray emission thus far are overenergetic, broad-lined Type Ic SNe (Hypernovae - HNe). Recently, SN 2008D shows several novel features: (i) weak XRF, (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SNIc HNe, (iv) development of He lines as in SNeIb. Detailed analysis shows that SN 2008D was not a normal SN: its explosion energy (KE ~ 6*10^{51} erg) and ejected mass (~7 Msun) are intermediate between normal SNeIbc and HNe. We derive that SN 2008D was originally a ~30Msun star. When it collapsed a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.
The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125
2008
We report on multi-wavelength observations, ranging from the X-ray to radio wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic observations reveal the presence of absorption lines due to O I, Si II, and C IV, implying a likely redshift of z = 1.547. The well-sampled light curves, in particular from 0.5 to 4 days after the burst, suggest a jet break at 3.7 days, corresponding to a jet opening angle of ~7.0 degrees, and implying an intrinsic GRB energy in the 1 - 10,000 keV band of around E = (6.3 - 6.9)x 10^(51) erg (based on the fluences measured by the gamma-ray detectors of the IPN network). GRB 070125 is among the brightest afterglows observed to date. The spectral energy distribution implies a host extinction of Av < 0.9 mag. Two rebrightening episodes are observed, one with excellent time coverage, showing an increase in flux of 56% in ~8000 seconds. The evolution of the afterglow light curve is achromatic at all times. Late-time observations of the afterglow do not show evidence for emission from an underlying host galaxy or supernova. Any host galaxy would be subluminous, consistent with current GRB host-galaxy samples. Evidence for strong Mg II absorption features is not found, which is perhaps surprising in view of the relatively high redshift of this burst and the high likelihood for such features along GRB-selected lines of sight.
Tobacco cv. Solaris seed cake as feed for light lambs: growth performance, carcase traits and meat quality
by
Palazzo, Marisa
,
Salimei, Elisabetta
,
Peng, Meng
in
agro-industrial co-product
,
lambs
,
marginal areas
2025
Sixteen crossbred male lambs, housed in eight pens, were fed two isoenergetic and isonitrogenous diets: Control (CTR; n = 8) and Nicotiana tabacum cv. Solaris seed cake (SSC; n = 8). During the trial, lasted 35 days, pen dry matter (DM) concentrate consumption was calculated, individual body weight recorded, and average daily gain (ADG) calculated. Physico-chemical analyses were carried out on samples of Longissimus dorsi (LD) and Semimembranosus (SM) muscles. Animals fed Solaris seed cake showed lower (p < 0.05) ADG and slaughter body weight than CTR group. Diet did not affect the DM concentrate consumption. CTR lambs had higher cold carcase weight and yield (p < 0.01), while the proportion of commercial cuts did not differ between groups. Diet did not affect meat colour; the pH was higher (p < 0.01) for SSC group. Meat total lipid, collagen and cholesterol contents were unaffected by the diet. Fatty acid composition showed lower palmitic acid (C16:0, p < 0.05) and higher stearic acid (C18:0, p < 0.01) content in SSC compared to CTR fed lambs. The LD muscle showed lower total lipid (p < 0.01) and collagen content (p < 0.05) than SM muscle, as well as higher proportion of total SFA (p < 0.01) and lower proportion of total PUFA (p < 0.01), n-3 PUFA (p < 0.05) and n-6 PUFA (p < 0.01). Further studies are needed for a better evaluation of the potential of the innovative tobacco Solaris co-product in lambs’ diet.
Journal Article
Soybean vs. Pea Bean in the Diet of Medium-Growing Broiler Chickens Raised under Semi-Intensive Conditions of Inner Mediterranean Areas: Growth Performance and Environmental Impact
2022
The effects of Glycine max L. (SOY) vs. Pisum sativum L. (PEA) in the diet were investigated on in vivo performance of two medium-growing broiler genotypes and on environmental impact. Sixty Kabir Red Plus and sixty New Red chickens were randomly allocated in 20 pens (n = 6 birds per pen). Each pen, i.e., experimental unit, received 1.18 kg dry matter (DM) including soybean (3.39%) in SOY, or pea bean (6.78%) in PEA groups. DM intake, DM refusals and bodyweight (BW) were recorded on pen basis, and average daily gain (ADG) and feed conversion rate (FCR) were calculated. Data on in vivo performance were processed by ANOVA General Linear Model followed by Student–Newman–Keuls post hoc test. Greenhouse gas (GHG) emissions were evaluated on a year basis by GLEAM-i software. The diet did not affect (p > 0.05) DM intake and DM refusals, BW, ADG and FCR. Diet x genotypes affected (p < 0.05) DM intake and DM refusals. PEA diet, cheaper than SOY diet, allowed the reduction in total GHG and CO2, and of meat emission intensity. However, an increase in total CH4 and N2O emissions was observed. The replacement of soybean with pea bean can represent a possible management strategy to reach trade-off between good farming practices and environmental protection on small-scale poultry farms of inner Mediterranean areas.
Journal Article
Addressing Cetacean–Fishery Interactions to Inform a Deep-Sea Ecosystem-Based Management in the Gulf of Taranto (Northern Ionian Sea, Central Mediterranean Sea)
by
Ingrosso, Maurizio
,
Carlucci, Roberto
,
Fanizza, Carmelo
in
Bathyal-benthic zone
,
Behavior
,
Biodiversity
2021
Understanding of cetaceans’ trophic role and the quantification of their impacts on the food web is a critical task, especially when data on their prey are linked to deep-sea ecosystems, which are often exposed to excessive exploitation of fishery resources due to poor management. This aspect represents one of the major issues in marine resource management, and trade-offs are needed to simultaneously support the conservation of cetaceans and their irreplaceable ecological role, together with sustainable fishing yield. In that regard, food web models can represent useful tools to support decision-making processes according to an ecosystem-based management (EBM) approach. This study provides a focus on the feeding activity occurrence and the trophic interactions between odontocetes and the fishery in the marine food web of the Gulf of Taranto (Northern Ionian Sea, Central Mediterranean Sea), by zooming in on cetaceans’ prey of commercial interest. In particular, the quantification of trophic impacts is estimated using a food web mass-balance model that integrates information on the bathymetric displacement of both cetaceans’ prey and fishing activity. The results are discussed from a management perspective to guide future research and knowledge enhancement activities as well as support the implementation of an EBM approach.
Journal Article
Carcass and Meat Quality Traits of Medium-Growing Broiler Chickens Fed Soybean or Pea Bean and Raised under Semi-Intensive Conditions
by
Palazzo, Marisa
,
Salimei, Elisabetta
,
Zejnelhoxha, Sanije
in
broiler chickens
,
diet
,
fatty acids
2022
A study was carried out to evaluate the effect of the total replacement of flaked soybean (Glycine max L., SOY) with raw pea (Pisum sativum L., PEA) on the carcass and meat quality traits of two medium-growing broiler strains (Kabir Rosso Plus, KB; New Red, NR). Birds were housed in 20 pens (five replications/groups, six birds each). At 83 days of age, 40 birds (2/replication) were slaughtered and the pectoral muscle (PM) was removed for analyses. Diet did not affect slaughter weight, carcass traits and meat quality. A pea diet determined a significant increase of MUFA and a decrease of PUFA, n-3 and n-6 PUFA; hence, the pea-fed group had a lower PUFA/SFA and a higher n-6/n-3 ratios compared to the soy-fed. NR chickens were heavier, with higher carcass and cut weights (p < 0.01) compared to KB chickens. Interactions (p < 0.05) between factors were found for PM weight and yield. Meat from NR had a higher (p < 0.05) pH. Fatty acids were slightly affected by genotype. Replacing soybean with pea adversely affects meat fatty acid composition in terms of nutritional profile.
Journal Article