46,469 research outputs found
Refined physical properties and g ′, r ′, i ′, z ′, J, H, K transmission spectrum of WASP-23b from the ground â
No full textContext. Multi-band observations of planetary transits using the telescope defocus technique may yield high-quality light curves suitable for refining the physical properties of exoplanets even with small or medium size telescopes. Such observations can be used to construct a broad-band transmission spectrum of transiting planets and search for the presence of strong absorbers. <BR /> Aims: We have thoroughly characterised the orbital ephemeris and physical properties of the transiting planet and host star in the WASP-23b system, constructed a broad-band transmission spectrum of <ASTROBJ>WASP-23 b</ASTROBJ> and performed a comparative analysis with theoretical models of hot Jupiters. <BR /> Methods: We observed a complete transit of <ASTROBJ>WASP-23 b</ASTROBJ> in seven passbands simultaneously, using the GROND instrument on the MPG/ESO 2.2 m telescope at La Silla Observatory and telescope defocussing. The optical data were taken in the Sloan g', r', i' and z' passbands. The resulting light curves are of high quality, with a root-mean-square scatter of the residual as low as 330 parts per million (ppm) in the z'-band, with a cadence of 90 s. Near-infrared data were obtained in the JHK passbands. We performed a MCMC analysis of our photometry plus existing radial velocity data to refine measurements of the ephemeris and physical properties of the WASP-23 system. We constructed a broad-band transmission spectrum of <ASTROBJ>WASP-23 b</ASTROBJ> and compared it with a theoretical transmission spectrum of a hot Jupiter. <BR /> Results: We measured the central transit time with a precision ~8 s. From this and earlier observations we obtain an orbital period of P = 2.9444300 ± 0.0000011 d. Our analysis also yielded a larger radius and mass for the planet (R<SUB>p</SUB> = 1.067<SUB>-0.038</SUB><SUP>+0.045</SUP> R<SUB>Jup</SUB> and M<SUB>p</SUB> = 0.917<SUB>-0.039</SUB><SUP>+0.040</SUP> M<SUB>Jup</SUB>) compared to previous estimates (R<SUB>p</SUB> = 0.962<SUB>-0.056</SUB><SUP>+0.047</SUP> R<SUB>Jup</SUB> and M<SUB>p</SUB> = 0.884<SUB>-0.094</SUB><SUP>+0.088</SUP> M<SUB>Jup</SUB>). The derived transmission spectrum is marginally flat, which is not surprising given the limited precision of the measurements for the planetary radius and the poor spectral resolution of the data. Based on observations collected with the Gamma Ray Burst Optical and Near-Infrared Detector (GROND) at the MPG/ESO-2.2 m telescope at La Silla Observatory, Chile. Programme 088.A-9006
Schooling and education.
No full textSchooling and education by Giles R. Wright with Howard L. Green and Lee R. Parks. Number 4 in the New Jersey Ethnic Life Series. Published by New Jersey Historical Commission
Physical properties of the WASP-44 planetary system from simultaneous multi-colour photometry
No full textWe present ground-based broad-band photometry of two transits in the WASP-44 planetary system obtained simultaneously through four optical (Sloan g<SUP>'</SUP>, r<SUP>'</SUP>, i<SUP>'</SUP>, z<SUP>'</SUP>) and three near-infrared (NIR; J, H, K) filters. We achieved low scatters of 1-2 mmag per observation in the optical bands with a cadence of ≈48 s, but the NIR-band light curves present much greater scatter. We also observed another transit of WASP-44 b by using a Gunn r filter and telescope defocussing, with a scatter of 0.37 mmag per point and an observing cadence around 135 s. We used these data to improve measurements of the time of mid-transit and the physical properties of the system. In particular, we improved the radius measurements of the star and planet by factors of 3 and 4, respectively. We find that the radius of WASP-44 b is 1.002 ± 0.033 ± 0.018 R<SUB>Jup</SUB> (statistical and systematic errors, respectively), which is slightly smaller than previously thought and differs from that expected for a core-free planet. In addition, with the help of a synthetic spectrum, we investigated the theoretically predicted variation of the planetary radius as a function of wavelength, covering the range 370-2440 nm. We can rule out extreme variations at optical wavelengths, but unfortunately our data are not precise enough (especially in the NIR bands) to differentiate between the theoretical spectrum and a radius which does not change with wavelength
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C.
No full textDE MAIESTATE / PRAESIDE M. JACOBO THOMASIO, MORALIS PHILOSOPH. P. P., PUBLICE DISPUTABIT JOHANNES DUNTE, R. L. AUTHOR & RESPON: AD DIEM 9. SEPTEMBR. H L. Q. C.
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C. (1)
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Broad-band transmission spectrum and K-band thermal emission of WASP-43b as observed from the ground
No full text<BR /> Aims: WASP-43b is the closest-orbiting hot Jupiter, and it has high bulk density. It causes deep eclipse depths in the system's light curve in both transit and occultation that is attributed to the cool temperature and small radius of its host star. We aim to secure a broad-band transmission spectrum and to detect its near-infrared thermal emission in order to characterize its atmosphere. <BR /> Methods: We observed one transit and one occultation event simultaneously in the g', r', i', z', J, H, K bands using the GROND instrument on the MPG/ESO 2.2-m telescope, where the telescope was heavily defocused in staring mode. After modeling the light curves, we derived wavelength-dependent transit depths and flux ratios and compared them to atmospheric models. <BR /> Results: From the transit event, we have independently derived WASP-43's system parameters with high precision and improved the period to be 0.81347437(13) days based on all the available timings. No significant variation in transit depths is detected, with the largest deviations coming from the i'-, H-, and K-bands. Given the observational uncertainties, the broad-band transmission spectrum can be explained by either (i) a flat featureless straight line that indicates thick clouds; (ii) synthetic spectra with absorption signatures of atomic Na/K, or molecular TiO/VO that in turn indicate cloud-free atmosphere; or (iii) a Rayleigh scattering profile that indicates high-altitude hazes. From the occultation event, we detected planetary dayside thermal emission in the K-band with a flux ratio of 0.197 ± 0.042%, which confirms previous detections obtained in the 2.09 μm narrow band and K<SUB>S</SUB>-band. The K-band brightness temperature 1878<SUP>+108</SUP><SUB>-116</SUB> K favors an atmosphere with poor day- to nightside heat redistribution. We also have a marginal detection in the i'-band (0.037<SUP>+0.023</SUP><SUB>-0.021</SUB>%), corresponding to T<SUB>B</SUB> = 2225<SUP>+139</SUP><SUB>-225</SUB> K, which is either a false positive, a signature of non-blackbody radiation at this wavelength, or an indication of reflective hazes at high altitude. Based on observations collected with the Gamma Ray Burst Optical and Near-Infrared Detector (GROND) on the MPG/ESO 2.2-m telescope at La Silla Observatory, Chile. Program 088.A-9016 (PI: Chen).Photometric time series are only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A40">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A40</A
Broad-band transmission spectrum and K-band thermal emission of WASP-43b as observed from the ground
No full text Aims: WASP-43b is the closest-orbiting hot Jupiter, and it has high bulk density. It causes deep eclipse depths in the system's light curve in both transit and occultation that is attributed to the cool temperature and small radius of its host star. We aim to secure a broad-band transmission spectrum and to detect its near-infrared thermal emission in order to characterize its atmosphere. Methods: We observed one transit and one occultation event simultaneously in the g', r', i', z', J, H, K bands using the GROND instrument on the MPG/ESO 2.2-m telescope, where the telescope was heavily defocused in staring mode. After modeling the light curves, we derived wavelength-dependent transit depths and flux ratios and compared them to atmospheric models. Results: From the transit event, we have independently derived WASP-43's system parameters with high precision and improved the period to be 0.81347437(13) days based on all the available timings. No significant variation in transit depths is detected, with the largest deviations coming from the i'-, H-, and K-bands. Given the observational uncertainties, the broad-band transmission spectrum can be explained by either (i) a flat featureless straight line that indicates thick clouds; (ii) synthetic spectra with absorption signatures of atomic Na/K, or molecular TiO/VO that in turn indicate cloud-free atmosphere; or (iii) a Rayleigh scattering profile that indicates high-altitude hazes. From the occultation event, we detected planetary dayside thermal emission in the K-band with a flux ratio of 0.197 ± 0.042%, which confirms previous detections obtained in the 2.09 μm narrow band and KS-band. The K-band brightness temperature 1878+108-116 K favors an atmosphere with poor day- to nightside heat redistribution. We also have a marginal detection in the i'-band (0.037+0.023-0.021%), corresponding to TB = 2225+139-225 K, which is either a false positive, a signature of non-blackbody radiation at this wavelength, or an indication of reflective hazes at high altitude. Based on observations collected with the Gamma Ray Burst Optical and Near-Infrared Detector (GROND) on the MPG/ESO 2.2-m telescope at La Silla Observatory, Chile. Program 088.A-9016 (PI: Chen).Photometric time series are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A40</A
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
L-invariants for cohomological representations of PGL(2) over arbitrary number fields
No full textGehrmann L, Pati MR. L-invariants for cohomological representations of PGL(2) over arbitrary number fields. Forum of Mathematics, Sigma. 2024;12: e71.**Abstract**
Let
be a cuspidal, cohomological automorphic representation of an inner form
G
of
over a number field
F
of arbitrary signature. Further, let
be a prime of
F
such that
G
is split at
and the local component
of
at
is the Steinberg representation. Assuming that the representation is noncritical at
, we construct automorphic
-invariants for the representation
. If the number field
F
is totally real, we show that these automorphic
-invariants agree with the Fontaine–Mazur
-invariant of the associated
p
-adic Galois representation. This generalizes a recent result of Spieß respectively Rosso and the first named author from the case of parallel weight
to arbitrary cohomological weights.
</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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