1,527 research outputs found

    Observations of two super fast rotator NEAs: 2021 NY1_1 and 2022 AB

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    In the framework of the Visible NEAs Observations Survey (ViNOS) that uses several telescopes at the Canary Islands observatories since 2018, we observed two super fast rotator NEAs, 2021 NY1_1 and 2022 AB. We obtained photometry and spectrophotometry of both targets and visible spectroscopy of 2022 AB. Light curves of 2021 NY1_1 obtained in 4 different nights between Sept. 30 and Oct. 16, 2021 return a rotation period P=13.3449±0.0013P=13.3449\pm0.0013 minutes and a light curve amplitude A=1.00A = 1.00 mag. We found that 2021 NY1_1 is a very elongated super fast rotator with an axis ratio a/b≥3.6a/b \ge 3.6. We also report colours (g−r)=0.664±0.013(g-r) = 0.664 \pm 0.013, (r−i)=0.186±0.013(r-i) = 0.186 \pm 0.013, and (i−zs)=−0.117±0.012(i-z_s) = -0.117 \pm 0.012 mag. These are compatible with an S-type asteroid. The light curves of 2022 AB obtained on Jan. 5 and Jan. 8, 2021 show a rotation period P=3.0304±0.0008P=3.0304\pm0.0008 minutes, with amplitudes A=0.52A = 0.52 and A=0.54A =0.54 mag. 2022 AB is also an elongated object with axis ratio a/b≥1.6a/b \ge 1.6. The obtained colours are (g−r)=0.400±0.017(g-r) = 0.400 \pm 0.017, (r−i)=0.133±0.017(r-i) = 0.133 \pm 0.017, and (i−zs)=0.093±0.016(i-z_s) = 0.093 \pm 0.016. These colours are similar to those of the X-types, but with an unusually high (g−r)(g-r) value. Spectra obtained on Jan. 12 and Jan. 14, 2022, are consistent with the reported colours. The spectral upturn over the 0.4 - 0.6 μm\mu m region of 2022 AB does not fit with any known asteroid taxonomical class or meteorite spectrum, confirming its unusual surface properties.Comment: 9 pages, 7 figure

    HLA Genes in Mayos Population from Northeast Mexico

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    HLA class I and class II alleles have been studied in 60 unrelated people belonging to Mayos ethnic group, which lives in the Mexican Pacific Sinaloa State. Mayos HLA profile was compared to other Amerindians and worldwide populations’ profile. A total of 14,896 chromosomes were used for comparisons. Genetic distances between populations, Neigbour-Joining dendrograms and correspondence analyses were performed to determine the genetic relationship among population. The new specific Mayo HLA haplotypes found are: HLA-A*02-B*35-DRB1*1406-DQB1*0301; HLA-A*02-B*48-DRB1*0404-DQB1*0302; HLA-A*24-B*51-DRB1*0407-DQB1*0302 and HLA-A*02-B*08-DRB1*0407-DQB1*0302. However, the typical Meso American HLADRB1*0407 represents a 40% of all DRB1 alleles. While common HLA characteristics are found in Amerindian distant ethnic groups, still new group specific HLA haplotypes are being found, suggesting that a common founder effect (i.e. high DRB1*0407) is noticed. Moreover, new HLA haplotypes are almost certainly appearing along time probably due to specific pathogen (?) selection for diversity. Mayo language is close to the Tarahumara one (another geographically close group); notwithstanding both groups are not genetically close according to our results, showing again the different evolution of genes and languages, which do not correlate. Finally, Sinaloa is one of the Mexican States in which more European genes are found. However, the results presented in this paper, where no European HLA genes are seen in Mayos, should have a bearing in establishing transplant programs and in HLA and disease studies

    Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium

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    We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm−1^{-1}. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/cc with a tensor polarized 2^2H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.Comment: 4 pages, 3 figure

    The PAU Survey: Photometric redshifts using transfer learning from simulations

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    In this paper we introduce the \textsc{Deepz} deep learning photometric redshift (photo-zz) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. \textsc{Deepz} reduces the σ68\sigma_{68} scatter statistic by 50\% at iAB=22.5i_{\rm AB}=22.5 compared to existing algorithms. This improvement is achieved through various methods, including transfer learning from simulations where the training set consists of simulations as well as observations, which reduces the need for training data. The redshift probability distribution is estimated with a mixture density network (MDN), which produces accurate redshift distributions. Our code includes an autoencoder to reduce noise and extract features from the galaxy SEDs. It also benefits from combining multiple networks, which lowers the photo-zz scatter by 10 percent. Furthermore, training with randomly constructed coadded fluxes adds information about individual exposures, reducing the impact of photometric outliers. In addition to opening up the route for higher redshift precision with narrow bands, these machine learning techniques can also be valuable for broad-band surveys.Comment: Accepted versio

    Spin-Momentum Correlations in Quasi-Elastic Electron Scattering from Deuterium

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    We report on a measurement of spin-momentum correlations in quasi-elastic scattering of longitudinally polarized electrons with an energy of 720 MeV from vector-polarized deuterium. The spin correlation parameter AedVA^V_{ed} was measured for the 2H⃗(e⃗,e′p)n^2 \vec{\rm H}(\vec e,e^\prime p)n reaction for missing momenta up to 350 MeV/cc at a four-momentum transfer squared of 0.21 (GeV/c)2^2. The data give detailed information about the spin structure of the deuteron, and are in good agreement with the predictions of microscopic calculations based on realistic nucleon-nucleon potentials and including various spin-dependent reaction mechanism effects. The experiment demonstrates in a most direct manner the effects of the D-state in the deuteron ground-state wave function and shows the importance of isobar configurations for this reaction.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Lett. for publicatio

    Relativistic effects and two-body currents in 2H(e⃗,e′p)n^{2}H(\vec{e},e^{\prime}p)n using out-of-plane detection

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    Measurements of the 2H(e⃗,e′p)n{^2}H(\vec{e},e^{\prime}p)n reaction were performed using an 800-MeV polarized electron beam at the MIT-Bates Linear Accelerator and with the out-of-plane magnetic spectrometers (OOPS). The longitudinal-transverse, fLTf_{LT} and fLT′f_{LT}^{\prime}, and the transverse-transverse, fTTf_{TT}, interference responses at a missing momentum of 210 MeV/c were simultaneously extracted in the dip region at Q2^2=0.15 (GeV/c)2^2. On comparison to models of deuteron electrodisintegration, the data clearly reveal strong effects of relativity and final-state interactions, and the importance of the two-body meson-exchange currents and isobar configurations. We demonstrate that these effects can be disentangled and studied by extracting the interference response functions using the novel out-of-plane technique.Comment: 4 pages, 4 figures, and submitted to PRL for publicatio
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