156 research outputs found
Open Issues on the Synthesis of Evolved Stellar Populations at Ultraviolet Wavelengths
In this paper we briefly review three topics that have motivated our (and
others') investigations in recent years within the context of evolutionary
population synthesis techniques. These are: The origin of the FUV up-turn in
elliptical galaxies, the age-metallicity degeneracy, and the study of the
mid-UV rest-frame spectra of distant red galaxies. We summarize some of our
results and present a very preliminary application of a UV grid of theoretical
spectra in the analysis of integrated properties of aged stellar populations.
At the end, we concisely suggest how these topics can be tackled once the World
Space Observatory enters into operation in the midst of this decade.Comment: 8 pages, 4 figures, accepted for publication in Astrophysics & Space
Science, UV Universe special issu
Conservation and prioritization of indigenous vegetables in the Philippines
Nutrition-related problems are a widespread challenge in the Philippines. Many factors contribute to these problems - the availability and affordability of vegetables, for example, which are jeopardized by challenges such as seasonality and inconsistent yields due to the impacts of climate change. Crop improvement and on-farm diversification, particularly using indigenous vegetables (IVs), can help address these challenges, while also improving rural livelihoods, nutrition, and food security; and even safeguarding local culture and tradition
Multiwavelength Photometry and Progenitor Analysis of the Nova V906 Car
We present optical and infrared photometry of the classical nova V906 Car, also known as Nova Car 2018 and ASASSN-18fv, which was discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) on 2018 March 16.32 UT (MJD 58193.0). The nova reached its maximum on MJD 58222.56 at V max = 5.84 ± 0.09 mag, and had decline times of t2, v = 26.2 days and t3, v = 33.0 days. The data from Evryscope shows that the nova had already brightened to g' â 13 mag five days before discovery, as compared with its quiescent magnitude of g = 20.13 ± 0.03. The extinction toward the nova, as derived from high-resolution spectroscopy, shows an estimate consistent with foreground extinction to the Carina Nebula of Av=1.11+0.54-0.39. The light curve resembles a rare C (cusp) class nova with a steep decline slope of α =-3.94 post-cusp flare. From the light-curve decline rate, we estimate the mass of the white dwarf to be M WD = <0.8M oË, consistent with MWD = 0.71+0.23-0.19 derived from modeling the accretion disk of the system in quiescence. The donor star is likely a K-M dwarf of 0.23-0.43 MoË, which is heated by its companion
Conserving and prioritizing indigenous fruits in the Philippines
Nutrition-related problems are a widespread challenge in the Philippines. Many factors contribute to these problems - the availability and affordability of fruits, for example, which are jeopardized by challenges such as seasonality and inconsistent yields due to the impacts of climate change. Crop improvement and on-farm diversification, particularly using indigenous fruits (IFs), can help address these challenges, while also improving rural livelihoods, nutrition, food security; and even safeguarding local culture and tradition
The PHENIX Experiment at RHIC
The physics emphases of the PHENIX collaboration and the design and current
status of the PHENIX detector are discussed. The plan of the collaboration for
making the most effective use of the available luminosity in the first years of
RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program
available at http://www.rhic.bnl.gov/phenix
Revisiting the HD 21749 planetary system with stellar activity modelling
HD 21749 is a bright (V = 8.1 mag) K dwarf at 16 pc known to host an inner terrestrial planet HD 21749c as well as an outer sub-Neptune HD 21749b, both delivered by Transiting Exoplanet Survey Satellite (TESS). Follow-up spectroscopic observations measured the mass of HD 21749b to be 22.7 ± 2.2 M with a density of 7.0^{+1.6}_{-1.3} g cm-3, making it one of the densest sub-Neptunes. However, the mass measurement was suspected to be influenced by stellar rotation. Here, we present new high-cadence PFS RV data to disentangle the stellar activity signal from the planetary signal. We find that HD 21749 has a similar rotational time-scale as the planet's orbital period, and the amplitude of the planetary orbital RV signal is estimated to be similar to that of the stellar activity signal. We perform Gaussian process regression on the photometry and RVs from HARPS and PFS to model the stellar activity signal. Our new models reveal that HD 21749b has a radius of 2.86 ± 0.20 R, an orbital period of 35.6133 ± 0.0005 d with a mass of Mb = 20.0 ± 2.7 M and a density of 4.8^{+2.0}_{-1.4} g cm-3 on an eccentric orbit with e = 0.16 ± 0.06, which is consistent with the most recent values published for this system. HD 21749c has an orbital period of 7.7902 ± 0.0006 d, a radius of 1.13 ± 0.10 R, and a 3Ï mass upper limit of 3.5 M. Our Monte Carlo simulations confirm that without properly taking stellar activity signals into account, the mass measurement of HD 21749b is likely to arrive at a significantly underestimated error bar
A search for the decay
We search for the rare flavor-changing neutral-current decay in a data sample of 82 fb collected with the {\sl BABAR}
detector at the PEP-II B-factory. Signal events are selected by examining the
properties of the system recoiling against either a reconstructed hadronic or
semileptonic charged-B decay. Using these two independent samples we obtain a
combined limit of
at the 90% confidence level. In addition, by selecting for pions rather than
kaons, we obtain a limit of using only the hadronic B reconstruction method.Comment: 7 pages, 8 postscript figures, submitted to Phys. Rev. Let
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