5,306 research outputs found

    Measures of galaxy dust and gas mass with Herschel photometry and prospects for ALMA

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    (Abridged) Combining the deepest Herschel extragalactic surveys (PEP, GOODS-H, HerMES), and Monte Carlo mock catalogs, we explore the robustness of dust mass estimates based on modeling of broad band spectral energy distributions (SEDs) with two popular approaches: Draine & Li (2007, DL07) and a modified black body (MBB). As long as the observed SED extends to at least 160-200 micron in the rest frame, M(dust) can be recovered with a >3 sigma significance and without the occurrence of systematics. An average offset of a factor ~1.5 exists between DL07- and MBB-based dust masses, based on consistent dust properties. At the depth of the deepest Herschel surveys (in the GOODS-S field) it is possible to retrieve dust masses with a S/N>=3 for galaxies on the main sequence of star formation (MS) down to M(stars)~1e10 [M(sun)] up to z~1. At higher redshift (z<=2) the same result is achieved only for objects at the tip of the MS or lying above it. Molecular gas masses, obtained converting M(dust) through the metallicity-dependent gas-to-dust ratio delta(GDR), are consistent with those based on the scaling of depletion time, and on CO spectroscopy. Focusing on CO-detected galaxies at z>1, the delta(GDR) dependence on metallicity is consistent with the local relation. We combine far-IR Herschel data and sub-mm ALMA expected fluxes to study the advantages of a full SED coverage.Comment: Accepted for publication in Astronomy and Astrophysics. Some figures have degraded quality for filesize reason

    A Search for Additional Bodies in the GJ 1132 Planetary System from 21 Ground-based Transits and a 100 Hour Spitzer Campaign

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    We present the results of a search for additional bodies in the GJ 1132 system through two methods: photometric transits and transit timing variations of the known planet. We collected 21 transit observations of GJ 1132b with the MEarth-South array since 2015. We obtained 100 near-continuous hours of observations with the SpitzerSpitzer Space Telescope, including two transits of GJ 1132b and spanning 60\% of the orbital phase of the maximum period at which bodies coplanar with GJ 1132b would pass in front of the star. We exclude transits of additional Mars-sized bodies, such as a second planet or a moon, with a confidence of 99.7\%. When we combine the mass estimate of the star (obtained from its parallax and apparent KsK_s band magnitude) with the stellar density inferred from our high-cadence SpitzerSpitzer light curve (assuming zero eccentricity), we measure the stellar radius of GJ 1132 to be 0.21050.0085+0.0102R0.2105^{+0.0102}_{-0.0085} R_\odot, and we refine the radius measurement of GJ 1132b to 1.130±0.056R1.130 \pm 0.056 R_\oplus. Combined with HARPS RV measurements, we determine the density of GJ 1132b to be 6.2±2.06.2 \pm 2.0\ g cm3^{-3}, with the mass determination dominating this uncertainty. We refine the ephemeris of the system and find no evidence for transit timing variations, which would be expected if there was a second planet near an orbital resonance with GJ 1132b.Comment: 29 pages, 4 Tables, 8 Figures, Submitted to ApJ. Comments welcom

    The rotation and Galactic kinematics of mid M dwarfs in the Solar Neighborhood

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    Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and are expected to have a different type of dynamo mechanism than solar-type stars. Measurements of their rotation rates provide insights into these mechanisms, but few rotation periods are available for these stars at field ages. Using photometry from the MEarth transit survey, we measure rotation periods for 387 nearby, mid-to-late M dwarfs in the Northern hemisphere, finding periods from 0.1 to 140 days. The typical detected rotator has stable, sinusoidal photometric modulations at a semi-amplitude of 0.5 to 1%. We find no period-amplitude relation for stars below 0.25Msun and an anti-correlation between period and amplitude for higher-mass M dwarfs. We highlight the existence of older, slowly-rotating stars without H{\alpha} emission that nevertheless have strong photometric variability. The Galactic kinematics of our sample is consistent with the local population of G and K dwarfs, and rotators have metallicities characteristic of the Solar Neighborhood. We use the W space velocities and established age-velocity relations to estimate that stars with P<10 days are on average <2 Gyrs, and that those with P>70 days are about 5 Gyrs. The period distribution is mass dependent: as the mass decreases, the slowest rotators at a given mass have longer periods, and the fastest rotators have shorter periods. We find a lack of stars with intermediate rotation periods. [Abridged]Comment: Accepted to ApJ. Machine readable tables and additional figures are available in the published article or on reques

    Adaptasi Usaha Mikro, Kecil, dan Menengah (UMKM) Bandeng Presto Selama Masa Pandemi Covid-19: Studi Kasus di Kota Semarang

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    Retnaningsih Ch, Bekti RB, Ruenda O. 2020. Adaptation of Presto Milkfish Small and Medium Enterprises (SMEs) during the covid-19 pandemic: a case study in Semarang city. In: Herlinda S et al. (Eds.), Prosiding Seminar Nasional Lahan Suboptimal ke-8 Tahun 2020, Palembang 20 Oktober 2020. pp. 1-11. Palembang: Penerbit & Percetakan Universitas Sriwijaya (UNSRI).Presto milkfish is one of the processed seafood product produced by SMEs in the city of Semarang. A case study conducted on 30 samples of SME processed seafood aims to determine the adaptations during the Covid-19 pandemic. The case study method is carried out by surveying the production location of SMEs. From the results of this case study, it was found that out of 18 samples of SMEs that produced presto milkfish, 72% had adapted their business in various ways such as product development innovation to improve quality. The number of samples of SMEs that innovated was 50%, and those that did not innovate on the products produced were 50%. Business adaptation by presto milkfish SMEs needs to be done for business continuity during the Covid-19 pandemic

    Theoretical Transit Spectra for GJ 1214b and Other "Super-Earths"

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    We present new calculations of transit spectra of super-Earths that allow for atmospheres with arbitrary proportions of common molecular species and haze. We test this method with generic spectra, reproducing the expected systematics and absorption features, then apply it to the nearby super-Earth GJ 1214b, which has produced conflicting observational data, leaving the questions of a hydrogen-rich versus hydrogen-poor atmosphere and the water content of the atmosphere ambiguous. We present representative transit spectra for a range of classes of atmosphere models for GJ 1214b. Our analysis supports a hydrogen-rich atmosphere with a cloud or haze layer, although a hydrogen-poor model with less than 10% water is not ruled out. Several classes of models are ruled out, however, including hydrogen-rich atmospheres with no haze, hydrogen-rich atmospheres with a haze of about 0.01-micron tholin particles, and hydrogen-poor atmospheres with major sources of absorption other than water. We propose an observational test to distinguish hydrogen-rich from hydrogen-poor atmospheres. Finally, we provide a library of theoretical transit spectra for super-Earths with a broad range of parameters to facilitate future comparison with anticipated data.Comment: 33 pages, 21 figures, 3 table

    PELATIHAN VERTIKULTUR KEPADA DASA WISMA MELATI 2 GEDANG ANAK UNGARAN TIMUR KABUPATEN SEMARANG SEBAGAI UPAYA MELESTARIKAN LINGKUNGAN SELAMA PANDEMIC COVID 19

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    Tim pengabdian melakukan kegiatan pengabdian pada ibu ibu dasa wisma melati 2 Gedang Anak Ungaran Timur Kabupaten Semarang selama masa pandemic covid 19. Pengabdian ini bertujuan untuk meningkatkan penghijauan dengan memanfaatkan lahan sempit yang dimiliki sekaligus memanfaatkan barang barang bekas seperti botol air mineral atau lainnya, melalui pelatihan vertikultur atau menanam secara bertingkat menggunakan pot dari botol air mineral atau barang bekas lainnya. Metode pelaksanaan pengabdian adalah mengajak ibu ibu dasa wisma untuk terlibat dalam mengumpulkan barang bekas dan melakukan penanaman tanaman secara vertikultur. Kesimpulan dari pengabdian ini adalah para ibu dapat memanfaatkan waktu di rumah selama pandemic covid 19 dengan menanam tanaman secara vertikal dan lingkungan menjadi semakin hijau.&nbsp;&nbsp;&nbsp; Kata kunci: Kesadaran lingkungan, Lahan Ssempit, Plastik, Vertikultur, Pemanfaatan&nbsp;barang bekas ABSTRACT The community service team carried out community service activities for the mother of the dasa wisma jasmine 2 Gedang Anak Ungaran Timur Semarang Regency during the Covid 19 pandemic. This service aims to increase reforestation by utilizing the narrow land that is owned while at the same time utilizing used goods such as mineral water bottles or others, through verticultural training or planting in terraced using pots from mineral water bottles or other used goods. The method of implementing this service is to invite dasa wisma mothers to be involved in collecting used goods and planting plants verticulture. The conclusion of this dedication is that mothers can take advantage of the time at home during the Covid 19 pandemic by planting plants vertically and the environment becoming greener. Keywords: Environmental Awareness, Verticulture, Narrow land, Plastic, Use of used good

    Decoupling with unitary approximate two-designs

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    Consider a bipartite system, of which one subsystem, A, undergoes a physical evolution separated from the other subsystem, R. One may ask under which conditions this evolution destroys all initial correlations between the subsystems A and R, i.e. decouples the subsystems. A quantitative answer to this question is provided by decoupling theorems, which have been developed recently in the area of quantum information theory. This paper builds on preceding work, which shows that decoupling is achieved if the evolution on A consists of a typical unitary, chosen with respect to the Haar measure, followed by a process that adds sufficient decoherence. Here, we prove a generalized decoupling theorem for the case where the unitary is chosen from an approximate two-design. A main implication of this result is that decoupling is physical, in the sense that it occurs already for short sequences of random two-body interactions, which can be modeled as efficient circuits. Our decoupling result is independent of the dimension of the R system, which shows that approximate 2-designs are appropriate for decoupling even if the dimension of this system is large.Comment: Published versio

    Fine-scale thermohaline ocean structure retrieved with 2-D prestack full-waveform inversion of multichannel seismic data: Application to the Gulf of Cadiz (SW Iberia)

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    18 pages, 9 figures, supporting information https://dx.doi.org/10.1002/2016JC011844This work demonstrates the feasibility of 2-D time-domain, adjoint-state acoustic full-waveform inversion (FWI) to retrieve high-resolution models of ocean physical parameters such as sound speed, temperature and salinity. The proposed method is first described and then applied to prestack multichannel seismic (MCS) data acquired in the Gulf of Cadiz (SW Iberia) in 2007 in the framework of the Geophysical Oceanography project. The inversion strategy flow includes specifically designed data preconditioning for acoustic noise reduction, followed by the inversion of sound speed in the shotgather domain. We show that the final sound speed model has a horizontal resolution of ∼ 70 m, which is two orders of magnitude better than that of the initial model constructed with coincident eXpendable Bathy Thermograph (XBT) data, and close to the theoretical resolution of O(λ). Temperature (T) and salinity (S) are retrieved with the same lateral resolution as sound speed by combining the inverted sound speed model with the thermodynamic equation of seawater and a local, depth-dependent T-S relation derived from regional conductivity-temperature-depth (CTD) measurements of the National Oceanic and Atmospheric Administration (NOAA) database. The comparison of the inverted T and S models with XBT and CTD casts deployed simultaneously to the MCS acquisition shows that the thermohaline contrasts are resolved with an accuracy of 0.18oC for temperature and 0.08 PSU for salinity. The combination of oceanographic and MCS data into a common, pseudo-automatic inversion scheme allows to quantitatively resolve submeso-scale features that ought to be incorporated into larger-scale ocean models of oceans structure and circulationThe work has been partially supported by the projects KALEIDOSCOPE and CO-Dos financed by REPSOL and MINECO project POSEIDON (CTM2010-21569) and HADES (CTM2011-30400-C02). B. Biescas work has been funded by the European Commission through the Marie Curie Action FP7-PEOPLE-2012-COFUND-600407Peer Reviewe
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