TY - JOUR A1 - Smith, Bryce A. A1 - Barlow, Brad N. A1 - Rosenthal, Benjamin A1 - Hermes, J. J. A1 - Schaffenroth, Veronika T1 - Pulse Timing Discovery of a Three-day Companion to the Hot Subdwarf BPM 36430 JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - Hot subdwarf B stars are core-helium-burning objects that have undergone envelope stripping, likely by a binary companion. Using high-speed photometry from the Transiting Exoplanet Survey Satellite, we have discovered the hot subdwarf BPM 36430 is a hybrid sdBV(rs) pulsator exhibiting several low-amplitude g-modes and a strong p-mode pulsation. The latter shows a clear, periodic variation in its pulse arrival times. Fits to this phase oscillation imply BPM 36430 orbits a barycenter approximately 10 light-seconds away once every 3.1 days. Using the CHIRON echelle spectrograph on the CTIO 1.5 m telescope, we confirm the reflex motion by detecting a radial-velocity variation with semiamplitude, period, and phase in agreement with the pulse timings. We conclude that a white dwarf companion with minimum mass of approximate to 0.42 M (circle dot) orbits BPM 36430. Our study represents only the second time a companion orbiting a pulsating hot subdwarf or white dwarf has been detected from pulse timings and confirmed with radial velocities. Y1 - 2022 U6 - https://doi.org/10.3847/1538-4357/ac9384 SN - 0004-637X SN - 1538-4357 VL - 939 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Geist, Emily A1 - Gallagher, John S. A1 - Kotulla, Ralf A1 - Oskinova, Lida A1 - Hamann, Wolf-Rainer A1 - Ramachandran, Varsha A1 - Sabbi, Elena A1 - Smith, Linda J. A1 - Kniazev, Alexey A1 - Nota, Antonella A1 - Rickard, Matthew J. T1 - Ionization and star formation in the giant H ii region SMC-N66 JF - Publications of the Astronomical Society of the Pacific N2 - The NGC 346 young stellar system and associated N66 giant H ii region in the Small Magellanic Cloud are the nearest example of a massive star-forming event in a low metallicity (Z approximate to 0.2Z (circle dot)) galaxy. With an age of less than or similar to 3 Myr this system provides a unique opportunity to study relationships between massive stars and their associated H ii region. Using archival data, we derive a total H alpha luminosity of L(H alpha) = 4.1 x 10(38) erg s(-1) corresponding to an H-photoionization rate of 3 x 10(50) s(-1). A comparison with a predicted stellar ionization rate derived from the more than 50 known O-stars in NGC 346, including massive stars recently classified from Hubble Space Telescope far-ultraviolet (FUV) spectra, indicates an approximate ionization balance. Spectra obtained with SALT suggest the ionization structure of N66 could be consistent with some leakage of ionizing photons. Due to the low metallicity, the FUV luminosity from NGC 346 is not confined to the interstellar cloud associated with N66. Ionization extends through much of the spatial extent of the N66 cloud complex, and most of the cloud mass is not ionized. The stellar mass estimated from nebular L(H alpha) appears to be lower than masses derived from the census of resolved stars which may indicate a disconnect between the formation of high and low mass stars in this region. We briefly discuss implications of the properties of N66 for studies of star formation and stellar feedback in low metallicity environments. Y1 - 2022 U6 - https://doi.org/10.1088/1538-3873/ac697b SN - 0004-6280 SN - 1538-3873 VL - 134 IS - 1036 PB - IOP Publishing CY - Bristol ER - TY - JOUR A1 - Crighton, Neil H. M. A1 - Prochaska, J. Xavier A1 - Murphy, Michael T. A1 - Worseck, Gabor A1 - Smith, Britton D. T1 - Imprints of the first billion years BT - Lyman limit systems at z similar to 5 JF - Monthly notices of the Royal Astronomical Society N2 - Lyman limit systems (LLSs) trace the low-density circumgalactic medium and the most dense regions of the intergalactic medium, so their number density and evolution at high-redshift, just after reionization, are important to constrain. We present a survey for LLSs at high redshifts, z(LLS) = 3.5-5.4, in the homogeneous data set of 153 optical quasar spectra at z similar to 5 from the Giant Gemini GMOS survey. Our analysis includes detailed investigation of survey biases using mock spectra which provide important corrections to the raw measurements. We estimate the incidence of LLSs per unit redshift at z approximate to 4.4 to be l(z) = 2.6 +/- 0.4. Combining our results with previous surveys at z(LLS) < 4, the best-fit power-law evolution is l(z) = l(*)[(1 + z)/4](alpha) with l* = 1.46 +/- 0.11 and alpha = 1.70 +/- 0.22 (68 per cent confidence intervals). Despite hints in previous z(LLS) < 4 results, there is no indication for a deviation from this single power-law soon after reionization. Finally, we integrate our new results with previous surveys of the intergalactic and circumgalactic media to constrain the hydrogen column density distribution function, f(N-HI, X), over 10 orders ofmagnitude. The data at z similar to 5 are not well-described by the f(N-HI, X) model previously reported for z similar to 2-3 (after re-scaling) and a 7-pivot model fitting the full z similar to 2-5 data set is statistically unacceptable. We conclude that there is significant evolution in the shape of f(N-HI, X) over this similar to 2-billion-year period. KW - quasars: absorption lines KW - cosmological parameters KW - cosmology: observations Y1 - 2019 U6 - https://doi.org/10.1093/mnras/sty2762 SN - 0035-8711 SN - 1365-2966 VL - 482 IS - 2 SP - 1456 EP - 1470 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Eigmüller, Philipp A1 - Chaushev, Alexander A1 - Gillen, Edward A1 - Smith, Alexis A1 - Nielsen, Louise D. A1 - Turner, Oliver A1 - Csizmadia, Szilard A1 - Smalley, Barry A1 - Bayliss, Daniel A1 - Belardi, Claudia A1 - Bouchy, Francois A1 - Burleigh, Matthew R. A1 - Cabrera, Juan A1 - Casewell, Sarah L. A1 - Chazelas, Bruno A1 - Cooke, Benjamin F. A1 - Erikson, Anders A1 - Gansicke, Boris T. A1 - Guenther, Maximilian N. A1 - Goad, Michael R. A1 - Grange, Andrew A1 - Jackman, James A. G. A1 - Jenkins, James S. A1 - McCormac, James A1 - Moyano, Maximiliano A1 - Pollacco, Don A1 - Poppenhäger, Katja A1 - Queloz, Didier A1 - Raynard, Liam A1 - Rauer, Heike A1 - Udry, Stephane A1 - Walker, Simon. R. A1 - Watson, Christopher A. A1 - West, Richard G. A1 - Wheatley, Peter J. T1 - NGTS-5b BT - a highly inflated planet offering insights into the sub-Jovian desert JF - Astronomy and astrophysics : an international weekly journal N2 - Context. Planetary population analysis gives us insight into formation and evolution processes. For short-period planets, the sub-Jovian desert has been discussed in recent years with regard to the planet population in the mass/period and radius/period parameter space without taking stellar parameters into account. The Next Generation Transit Survey (NGTS) is optimised for detecting planets in this regime, which allows for further analysis of the sub-Jovian desert. Aims. With high-precision photometric surveys (e.g. with NGTS and TESS), which aim to detect short period planets especially around M/K-type host stars, stellar parameters need to be accounted for when empirical data are compared to model predictions. Presenting a newly discovered planet at the boundary of the sub-Jovian desert, we analyse its bulk properties and use it to show the properties of exoplanets that border the sub-Jovian desert. Methods. Using NGTS light curve and spectroscopic follow-up observations, we confirm the planetary nature of planet NGTS-5b and determine its mass. Using exoplanet archives, we set the planet in context with other discoveries. Results. NGTS-5b is a short-period planet with an orbital period of 3.3569866 +/- 0.0000026 days. With a mass of 0.229 +/- 0.037 M-Jup and a radius of 1.136 +/- 0.023 R-Jup, it is highly inflated. Its mass places it at the upper boundary of the sub-Jovian desert. Because the host is a K2 dwarf, we need to account for the stellar parameters when NGTS-5b is analysed with regard to planet populations. Conclusions. With red-sensitive surveys (e.g. with NGTS and TESS), we expect many more planets around late-type stars to be detected. An empirical analysis of the sub-Jovian desert should therefore take stellar parameters into account. KW - planets and satellites: detection KW - planets and satellites: gaseous planets Y1 - 2019 U6 - https://doi.org/10.1051/0004-6361/201935206 SN - 1432-0746 VL - 625 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Borde, Ron A1 - Smith, Jordan J. A1 - Sutherland, Rachel A1 - Nathan, Nicole A1 - Lubans, David Revalds T1 - Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis JF - Obesity reviews : an official journal of the International Association for the Study of Obesity N2 - Objective: The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions. Methods: A systematic search was performed to identify randomized controlled trials targeting adolescents (age: >= 10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored. Results: Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects. Conclusion: Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols. KW - Accelerometer KW - physical activity KW - school KW - youth Y1 - 2017 U6 - https://doi.org/10.1111/obr.12517 SN - 1467-7881 SN - 1467-789X VL - 18 SP - 476 EP - 490 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Saikin, Anthony A1 - Jordanova, Vania K. A1 - Zhang, J. C. A1 - Smith, C. W. A1 - Spence, H. E. A1 - Larsen, B. A. A1 - Reeves, G. D. A1 - Torbert, R. B. A1 - Kletzing, C. A. A1 - Zhelayskaya, I. S. A1 - Shprits, Yuri Y. T1 - Comparing simulated and observed EMIC wave amplitudes using in situ Van JF - Journal of Atmospheric and Solar-Terrestrial Physics N2 - We perform a statistical study calculating electromagnetic ion cyclotron (EMIC) wave amplitudes based off in situ plasma measurements taken by the Van Allen Probes’ (1.1–5.8 Re) Helium, Oxygen, Proton, Electron (HOPE) instrument. Calculated wave amplitudes are compared to EMIC waves observed by the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes during the same period. The survey covers a 22-month period (1 November 2012 to 31 August 2014), a full Van Allen Probe magnetic local time (MLT) precession. The linear theory proxy was used to identify EMIC wave events with plasma conditions favorable for EMIC wave excitation. Two hundred and thirty-two EMIC wave events (103 H+-band and 129 He+-band) were selected for this comparison. Nearly all events selected are observed beyond L = 4. Results show that calculated wave amplitudes exclusively using the in situ HOPE measurements produce amplitudes too low compared to the observed EMIC wave amplitudes. Hot proton anisotropy (Ahp) distributions are asymmetric in MLT within the inner (L < 7) magnetosphere with peak (minimum) Ahp, ∼0.81 to 1.00 (∼0.62), observed in the dawn (dusk), 0000 < MLT ≤ 1200 (1200 < MLT ≤ 2400), sectors. Measurements of Ahp are found to decrease in the presence of EMIC wave activity. Ahp amplification factors are determined and vary with respect to EMIC wave-band and MLT. He+-band events generally require double (quadruple) the measured Ahp for the dawn (dusk) sector to reproduce the observed EMIC wave amplitudes. KW - EMIC waves KW - Van Allen Probes KW - Linear theory KW - Wave generation Y1 - 2018 U6 - https://doi.org/10.1016/j.jastp.2018.01.024 SN - 1364-6826 SN - 1879-1824 VL - 177 SP - 190 EP - 201 PB - Elsevier CY - Oxford ER -