The Astropy Project : sustaining and growing a community-oriented open-source project and the latest major release (v5.0) of the core package

Funding: We acknowledge the Gordon and Betty Moore Foundation for their continued financial support. This work is partially supported by NASA under grant No. 80NSSC22K0347 issued through the NASA ROSES program. This work is partially supported by the international Gemini Observatory, a programof NSF’s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation, on behalf of the Gemini partnership of Argentina, Brazil, Canada, Chile, the Republic of Korea, and the United States of America. We also thank NumFOCUS and the Python Software Foundation for financial support. J.A.A.-M. acknowledges funding support from Macquarie University through the International Macquarie University Research Excellence Scholarship (“iMQRES”). A.B. was supported by the Lendület Program of the Hungarian Academy of Sciences, project No. LP2018-7, and the KKP-137523 “SeismoLab” Élvonal grant of the Hungarian Research, Development and Innovation Office (NKFIH). M.B. gratefully acknowledges support from the ANID BASAL project FB210003 and the FONDECYT regular grant 1211000. F.D. E. acknowledges funding through the H2020 ERC Consolidator grant 683184, the ERC Advanced grant 695671 “QUENCH” and support from the Science and Technology Facilities Council (STFC). N.K. acknowledges support from the MIT Pappalardo fellowship. K.A.O. acknowledges support from the European Research Council (ERC) through Advanced Investigator grant to C.S. Frenk, DMIDAS (GA 786910). C.P. is supported by the Canadian Space Agency under a contract with NRC Herzberg Astronomy and Astrophysics. S.P. has been supported by Spanish MINECO-FEDER grant RTI2018-096188-B-I00 J.P.G. acknowledges funding support from Spanish public funds for research from project PID2019-107061GB-C63 from the “Programas Estatales de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I+D+i y de I+D+i Orientada a los Retos de la Sociedad,” as well as from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). N.S. acknowledges support from the National Science Foundation through the Graduate Research Fellowship Program under grant 1842402. D.S. is supported by STFC grant ST/S000240/1. N.S. acknowledges the support of the Science and Engineering Research Council of Canada (NSERC) Canadian Graduate Scholarship—Doctoral Program, [funding reference numbers CGSD547212020].The Astropy Project supports and fosters the development of open-source and openly developed Python packages that provide commonly needed functionality to the astronomical community. A key element of the Astropy Project is the core package astropy, which serves as the foundation for more specialized projects and packages. In this article, we summarize key features in the core package as of the recent major release, version 5.0, and provide major updates on the Project. We then discuss supporting a broader ecosystem of interoperable packages, including connections with several astronomical observatories and missions. We also revisit the future outlook of the Astropy Project and the current status of Learn Astropy. We conclude by raising and discussing the current and future challenges facing the Project.Publisher PDFPeer reviewe

Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus. The analysis has been carried out by using lubrication theory. The study is particularly suitable for cases where the Reynolds number is small. The esophagus is treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall. Variation of different variables concerned with the transport phenomena such as pressure, flow velocity, particle trajectory and reflux are investigated for a single wave as well as for a train of periodic peristaltic waves. Locally variable pressure is seen to be highly sensitive to the flow index `n'. The study clearly shows that continuous fluid transport for Newtonian/rheological fluids by wave train propagation is much more effective than widely spaced single wave propagation in the case of peristaltic movement of food bolus in the esophagus.Comment: Accepted for publication in Applied Mathematics and Mechanics (AMM), Springe

In search of virus carriers of the 1988 and 2002 phocine distemper virus outbreaks in European harbour seals

European harbour seal (Phoca vitulina) populations decreased substantially during the phocine distemper virus (PDV) outbreaks of 1988 and 2002. Different hypotheses have stated that various seals and terrestrial carnivore species might be the source of infection. To further analyse these hypotheses, grey (Halichoerus grypus) and ringed (Phoca hispida) seals, polar bears (Ursus maritimus) and minks (Mustela lutreola) were sampled from the North Sea and East Greenland coasts between 1988 and 2004 and investigated by RT-PCR using a panmorbillivirus primer pair. However, all samples were negative for morbillivirus nucleic acid

Physical Response of the York River Estuary to Hurricane Isabel

After making landfall on the North Carolina coast on the morning of 18 September 2003, Category 2 Hurricane Isabel tracked northward parallel to and slightly west of the Chesapeake Bay. At Gloucester Point, near the mouth of the York River estuary, strong onshore winds with speeds in excess of 20 m⋅s-1 persisted for over 12 hours and peak winds reached over 40 m⋅s-1, causing a sustained up-estuary wind stress. Storm surge exceeded 2 m throughout most of the lower Chesapeake Bay. A 600 kHz acoustic Doppler current profiler (ADCP), deployed at a depth of 8.5 m off Gloucester Point, provided high-quality data on waves, storm surge, currents, and acoustic backscatter throughout the water column before, during, and after the storm. Pressure and salinity sensors at three additional sites further up the estuary provided information on water surface slope and saltwater excursion up the estuary. A first-order estimate of three terms of the along-channel momentum equation (barotropic pressure gradient, acceleration, and friction) showed that the pressure gradient appeared to be balanced by the wind stress and the acceleration during the storm. The storm’s path and slow speed were the primary causes of the extremely high storm surge relative to past storms in the area.https://scholarworks.wm.edu/vimsbooks/1001/thumbnail.jp

Constraints on Stellar Flare Energy Ratios in the NUV and Optical From a Multiwavelength Study of GALEX and Kepler Flare Stars

We present a multiwavelength study of stellar flares on primarily G-type stars using overlapping time domain surveys in the near ultraviolet (NUV) and optical regimes. The NUV (GALEX) and optical (Kepler) wavelength domains are important for understanding energy fractionations in stellar flares, and for constraining the associated incident radiation on a planetary atmosphere. We follow up on the NUV flare detections presented in Brasseur et al. 2019, using coincident Kepler long (1557 flares) and short (2 flares) cadence light curves. We find no evidence of optical flares at these times, and place limits on the flare energy ratio between the two wavebands. We find that the energy ratio is correlated with GALEX band energy, and extends over a range of about three orders of magnitude in the ratio of the upper limit of Kepler band flare energy to NUV flare energy at the same time for each flare. The two flares with Kepler short cadence data indicate that the true Kepler band energy may be much lower than the long cadence based upper limit. A similar trend appears for the bulk flare energy properties of non-simultaneously observed flares on the same stars. We provide updated models to describe the flare spectral energy distribution from the NUV through the optical including continua and emission lines to improve upon blackbody-only models. The spread of observed energy ratios is much larger than encompassed by these models and suggests new physics is at work. These results call for better understanding of NUV flare physics and provide a cautionary tale about using only optical flare measurements to infer the UV irradiation of close-in planets.Comment: 33 pages, 17 figures, 6 table. Accepted for publication in the Astrophysical Journal. Associated analysis code on github here: https://github.com/ceb8/optical_nuv_multiwavelength_flare_study/blob/main/README.m

Simulations over South Asia using the Weather Research and Forecasting model with Chemistry (WRF-Chem): set-up and meteorological evaluation

The configuration and evaluation of the meteorology is presented for simulations over the South Asian region using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). Temperature, water vapor, dew point temperature, zonal and meridional wind components, precipitation and tropopause pressure are evaluated against radiosonde and satellite-borne (AIRS and TRMM) observations along with NCEP/NCAR reanalysis fields for the year 2008. Chemical fields, with focus on tropospheric ozone, are evaluated in a companion paper. The spatial and temporal variability in meteorological variables is well simulated by the model with temperature, dew point temperature and precipitation showing higher values during summer/monsoon and lower during winter. The index of agreement for all the parameters is estimated to be greater than 0.6 indicating that WRF-Chem is capable of simulating the variations around the observed mean. The mean bias (MB) and root mean square error (RMSE) in modeled temperature, water vapor and wind components show an increasing tendency with altitude. MB and RMSE values are within ±2 K and 1–4 K for temperature, 30% and 20–65% for water vapor and 1.6 m s<sup>−1</sup> and 5.1 m s<sup>−1</sup> for wind components. The spatio-temporal variability of precipitation is also reproduced reasonably well by the model but the model overestimates precipitation in summer and underestimates precipitation during other seasons. Such a behavior of modeled precipitation is in agreement with previous studies on South Asian monsoon. The comparison with radiosonde observations indicates a relatively better model performance for inland sites as compared to coastal and island sites. The MB and RMSE in tropopause pressure are estimated to be less than 25 hPa. Sensitivity simulations show that biases in meteorological simulations can introduce errors of ±(10–25%) in simulations of tropospheric ozone, CO and NO<sub>x</sub>. Nevertheless, a comparison of statistical metrics with benchmarks indicates that the model simulated meteorology is of sufficient quality for use in chemistry simulations

New Time-Resolved, Multi-Band Flares In The GJ 65 System With gPhoton

Characterizing the distribution of flare properties and occurrence rates is important for understanding habitability of M dwarf exoplanets. The GALEX space telescope observed the GJ 65 system, composed of the active, flaring M stars BL Cet and UV Cet, for 15900 seconds (~4.4 hours) in two ultraviolet bands. The contrast in flux between flares and the photospheres of cool stars is maximized at ultraviolet wavelengths, and GJ 65 is the brightest and nearest flaring M dwarf system with significant GALEX coverage. It therefore represents the best opportunity to measure low energy flares with GALEX. We construct high cadence light curves from calibrated photon events and find 13 new flare events with NUV energies ranging from 10^28.5 - 10^29.5 ergs and recover one previously reported flare with an energy of 10^31 ergs. The newly reported flares are among the smallest M dwarf flares observed in the ultraviolet with sufficient time resolution to discern light curve morphology. The estimated flare frequency at these low energies is consistent with extrapolation from the distributions of higher-energy flares on active M dwarfs measured by other surveys. The largest flare in our sample is bright enough to exceed the local non-linearity threshold of the GALEX detectors, which precludes color analysis. However, we detect quasi-periodic pulsations (QPP) during this flare in both the FUV and NUV bands at a period of ~50 seconds, which we interpret as a modulation of the flare's chromospheric thermal emission through periodic triggering of reconnection by external MHD oscillations in the corona.Comment: 22 pages, 20 figures, Jupyter Python notebooks to reproduce figures and tables available on GitHub at https://github.com/MillionConcepts/gfcat_gj6