5,088 research outputs found
Panchromatic spectral energy distributions of Herschel sources
Combining far-infrared Herschel photometry from the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time programs with ancillary datasets in the GOODS-N, GOODS-S, and COSMOS fields, it is possible to sample the 8–500 μm spectral energy distributions (SEDs) of galaxies with at least 7–10 bands. Extending to the UV, optical, and near-infrared, the number of bands increases up to 43. We reproduce the distribution of galaxies in a carefully selected restframe ten colors space, based on this rich data-set, using a superposition of multivariate Gaussian modes. We use this model to classify galaxies and build median SEDs of each class, which are then fitted with a modified version of the magphys code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an active galactic nucleus (AGN). The color distribution of galaxies in each of the considered fields can be well described with the combination of 6–9 classes, spanning a large range of far- to near-infrared luminosity ratios, as well as different strength of the AGN contribution to bolometric luminosities. The defined Gaussian grouping is used to identify rare or odd sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z ~ 1 Ly-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, and compared to eightother popular methods often adopted in the literature. When implementing Herschel photometry, these approaches produce L(IR) values consistent with each other within a median absolute deviation of 10–20%, the scatter being dominated more by fine tuning of the codes, rather than by the choice of SED templates. Finally, the library is used to classify 24 μm detected sources in PEP GOODS fields on the basis of AGN content, L(60)/L(100) color and L(160)/L(1.6) luminosity ratio. AGN appear to be distributed in the stellar mass (M_∗) vs. star formation rate (SFR) space along with all other galaxies, regardless of the amount of infrared luminosity they are powering, with the tendency to lie on the high SFR side of the “main sequence”. The incidence of warmer star-forming sources grows for objects with higher specific star formation rates (sSFR), and they tend to populate the “off-sequence” region of the M_∗ − SFR − z space
Measures of galaxy dust and gas mass with Herschel photometry and prospects for ALMA
(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
Thermal States as Convex Combinations of Matrix Product States
We study thermal states of strongly interacting quantum spin chains and prove
that those can be represented in terms of convex combinations of matrix product
states. Apart from revealing new features of the entanglement structure of
Gibbs states our results provide a theoretical justification for the use of
White's algorithm of minimally entangled typical thermal states. Furthermore,
we shed new light on time dependent matrix product state algorithms which yield
hydrodynamical descriptions of the underlying dynamics.Comment: v3: 10 pages, 2 figures, final published versio
Entropic uncertainty and measurement reversibility
The entropic uncertainty relation with quantum side information (EUR-QSI) from (Berta et al 2010 Nat. Phys. 6 659) is a unifying principle relating two distinctive features of quantum mechanics: quantum uncertainty due to measurement incompatibility, and entanglement. In these relations, quantum uncertainty takes the form of preparation uncertainty where one of two incompatible measurements is applied. In particular, the 'uncertainty witness' lower bound in the EUR-QSI is not a function of a post-measurement state. An insightful proof of the EUR-QSI from (Coles et al 2012 Phys. Rev. Lett. 108 210405) makes use of a fundamental mathematical consequence of the postulates of quantum mechanics known as the non-increase of quantum relative entropy under quantum channels. Here, we exploit this perspective to establish a tightening of the EUR-QSI which adds a new state-dependent term in the lower bound, related to how well one can reverse the action of a quantum measurement. As such, this new term is a direct function of the post-measurement state and can be thought of as quantifying how much disturbance a given measurement causes. Our result thus quantitatively unifies this feature of quantum mechanics with the others mentioned above. We have experimentally tested our theoretical predictions on the IBM quantum experience and find reasonable agreement between our predictions and experimental outcomes
The Effect of Family Economic Education Towards Lifestyle Mediated by Financial Literacy
The objectives of the study were to describe the planning, implementation, observation and reflection, to evaluate and identify the constraints and solutions at each cycle and also to find out the learning outcomes achieved with scientific approach through the discovery learning model for 2nd grade students at SMP 2 Kudus. It was a descriptive qualitative study. The research result showed that the students' activity was enough on the first cycle and good on the second cycle. The average mean score of the written test on the first first cycles B- and A- on the second cycle. If it was seen from the minimum completeness criterion (KKM), there were 19 students with the percentage of acquisition was 55% on the 1st cycle and there were 32 students with the percentage of acquisition was 93% on the 2nd cycle. The observation results showed that scientific approach gave improvement of students' activities on the first cycle and the second cycle. The results obtained from the use of scientific approach through the discovery learning model to improve the activity was good, but it needs to be observed continuously on students' attitudes, skills and knowledge in school life.Penelitian ini dilakukan untuk melihat gaya hidup yang dimiliki oleh mahasiswa apakah dipengaruhi oleh pendidikan yang telah diterima dikeluarga dan financial literacy mereka. Serta pengaruh financial literacy sebagai mediasi untuk pendidikan ekonomi dikeluarga terhadap gaya hidup. Sampel dipilih berjumlah 334 dari populasi 2040 mahasiswa Universitas Indraprasta PGRI Jakarta. Teknik analisis data menggunakan path analysis.Deskripsi data diperoleh bahwa 60,78% mahasiswa pada kategori sedang untuk pendidikan ekonomi dikeluarga, 47% mahasiswa pada kategori tinggi untuk financial literacy dan 58% mahasiswa memiliki gaya hidup tinggi. Penelitian menyimpulkan bahwa (1) pendidikan ekonomi mempengaruhi gaya hidup sebesar 6,4%, (2) financial literacy mempengaruhi sebesar 3,7% terhadap gaya hidup dan (3) pengaruh pendidikan ekonomi dikeluarga melalui financial literacy terhadap gaya hidup sebesar 1,9%. Dapat disimpulkan bahwa financial literacy tidak meningkatkan pengaruh pendidikan ekonomi dikeluarga terhadap gaya hidup. Hasil penelitian akan digunakan sebagai salah satu acuan dalam penerapan perkuliahan kewirausahaan
Star formation properties of sub-mJy radio sources
We investigate the star formation properties of ~800 sources detected in one
of the deepest radio surveys at 1.4 GHz. Our sample spans a wide redshift range
(~0.1 - 4) and about four orders of magnitude in star formation rate (SFR). It
includes both star forming galaxies (SFGs) and active galactic nuclei (AGNs),
further divided into radio-quiet and radio-loud objects. We compare the SFR
derived from the far infrared luminosity, as traced by Herschel, with the SFR
computed from their radio emission. We find that the radio power is a good SFR
tracer not only for pure SFGs but also in the host galaxies of RQ AGNs, with no
significant deviation with redshift or specific SFR. Moreover, we quantify the
contribution of the starburst activity in the SFGs population and the
occurrence of AGNs in sources with different level of star formation. Finally
we discuss the possibility of using deep radio survey as a tool to study the
cosmic star formation history.Comment: 18 pages, 14 figures, 1 table (available in its entirety as ancillary
data
The PEP Survey: Infrared Properties of Radio-Selected AGN
By exploiting the VLA-COSMOS and the Herschel-PEP surveys, we investigate the
Far Infrared (FIR) properties of radio-selected AGN. To this purpose, from
VLA-COSMOS we considered the 1537, F[1.4 GHz]>0.06 mJy sources with a reliable
redshift estimate, and sub-divided them into star-forming galaxies and AGN
solely on the basis of their radio luminosity. The AGN sample is complete with
respect to radio selection at all z<~3.5. 832 radio sources have a counterpart
in the PEP catalogue. 175 are AGN. Their redshift distribution closely
resembles that of the total radio-selected AGN population, and exhibits two
marked peaks at z~0.9 and z~2.5. We find that the probability for a
radio-selected AGN to be detected at FIR wavelengths is both a function of
radio power and redshift, whereby powerful sources are more likely to be FIR
emitters at earlier epochs. This is due to two distinct effects: 1) at all
radio luminosities, FIR activity monotonically increases with look-back time
and 2) radio activity of AGN origin is increasingly less effective at
inhibiting FIR emission. Radio-selected AGN with FIR emission are
preferentially located in galaxies which are smaller than those hosting
FIR-inactive sources. Furthermore, at all z<~2, there seems to be a
preferential (stellar) mass scale M ~[10^{10}-10^{11}] Msun which maximizes the
chances for FIR emission. We find such FIR (and MIR) emission to be due to
processes indistinguishable from those which power star-forming galaxies. It
follows that radio emission in at least 35% of the entire AGN population is the
sum of two contributions: AGN accretion and star-forming processes within the
host galaxy.Comment: 13 pages, 14 figures, to appear in MNRA
Theoretical Transit Spectra for GJ 1214b and Other "Super-Earths"
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
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