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See detailGround-based follow-up observations of TRAPPIST-1 transits in the near-infrared
Burdanov, Artem ULiege; Lederer, S. M.; Gillon, Michaël ULiege et al

in Monthly Notices of the Royal Astronomical Society (2019), 487

The TRAPPIST-1 planetary system is a favourable target for the atmospheric characterization of temperate earth-sized exoplanets by means of transmission spectroscopy with the forthcoming James Webb Space ... [more ▼]

The TRAPPIST-1 planetary system is a favourable target for the atmospheric characterization of temperate earth-sized exoplanets by means of transmission spectroscopy with the forthcoming James Webb Space Telescope (JWST). A possible obstacle to this technique could come from the photospheric heterogeneity of the host star that could affect planetary signatures in the transit transmission spectra. To constrain further this possibility, we gathered an extensive photometric data set of 25 TRAPPIST-1 transits observed in the near-IR J band (1.2 μm) with the UKIRT and the AAT, and in the NB2090 band (2.1 μm) with the VLT during the period 2015-18. In our analysis of these data, we used a special strategy aiming to ensure uniformity in our measurements and robustness in our conclusions. We reach a photometric precision of 0.003 (RMS of the residuals), and we detect no significant temporal variations of transit depths of TRAPPIST-1 b, c, e, and g over the period of 3 yr. The few transit depths measured for planets d and f hint towards some level of variability, but more measurements will be required for confirmation. Our depth measurements for planets b and c disagree with the stellar contamination spectra originating from the possible existence of bright spots of temperature 4500 K. We report updated transmission spectra for the six inner planets of the system which are globally flat for planets b and g and some structures are seen for planets c, d, e, and f. [less ▲]

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See detailLong-term soft and hard X-ray investigation of the colliding wind WN+O binary WR 25
Arora, Barthi; Pandey, Jeewan C.; De Becker, Michaël ULiege

in Monthly Notices of the Royal Astronomical Society (2019), 487

We investigated the long-term behaviour in X-rays of the colliding wind binary WR 25, using archival data obtained with Suzaku, Swift, XMM-Newton, and NuSTAR spanning over ̃16 yr. Our analysis reveals ... [more ▼]

We investigated the long-term behaviour in X-rays of the colliding wind binary WR 25, using archival data obtained with Suzaku, Swift, XMM-Newton, and NuSTAR spanning over ̃16 yr. Our analysis reveals phase-locked variations repeating consistently over many consecutive orbits, in agreement with an X-ray emission fully explained by thermal emission from the colliding winds in the 208-d orbit. We report on a significant deviation of the X-ray flux with respect to the 1/D trend (expected for adiabatic shocked winds) close to periastron passage. The absence of a drop in post-shock plasma temperature close to periastron suggests this break in trend cannot be explained in terms of reduced pre-shock velocities in this part of the orbit. Finally, NuSTAR data reveal a lack of hard X-ray emission (above 10.0 keV) above the background level. Upper limits on a putative non-thermal emission strongly suggest that the sensitivity of present hard X-ray observatories is not sufficient to detect non-thermal emission from massive binaries above 10 keV, unless the wind kinetic power is large enough to significantly feed particle acceleration in the wind-wind interaction. [less ▲]

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See detailSeparating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI
Christiaens, V.; Casassus, S.; Absil, Olivier ULiege et al

in Monthly Notices of the Royal Astronomical Society (2019), 486

Transition discs are prime targets to look for protoplanets and study planet-disc interactions. We present VLT/SINFONI observations of PDS 70, a transition disc with a recently claimed embedded ... [more ▼]

Transition discs are prime targets to look for protoplanets and study planet-disc interactions. We present VLT/SINFONI observations of PDS 70, a transition disc with a recently claimed embedded protoplanet. We take advantage of the angular and spectral diversity present in our data for an optimal PSF modelling and subtraction using principal component analysis (PCA). We report the redetection of PDS 70 b, both the front and far side of the outer disc edge, and the detection of several extended features in the annular gap. We compare spectral differential imaging applied before (PCA-SADI), and after (PCA-ASDI) angular differential imaging. Our tests suggest that PCA-SADI better recovers extended features, while PCA-ASDI is more sensitive to point sources. We adapted the negative fake companion (NEGFC) technique to infer the astrometry of the companion, and derived r = 193.5 ± 4.9 mas and PA =158.7[SUP]°[/SUP] ± 3.0[SUP]°[/SUP]. We used both NEGFC and ANDROMEDA to infer the K-band spectro-photometry of the protoplanet, and found results consistent with recent VLT/SPHERE observations, except for their 2018/02 epoch measurement in the K2 filter. Finally, we derived an upper limit of \dot{M_b} < 1.26 × 10^{-7} \big [ 5 M_Jup/M_b \big ] \big [ R_b/R_Jup\big ] M_Jup yr[SUP]-1[/SUP] for the accretion rate of the companion based on an adaptation of PCA-SADI/PCA-ASDI around the Brγ line (assuming no extinction). [less ▲]

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See detailThree hot-Jupiters on the upper edge of the mass-radius distribution: WASP-177, WASP-181, and WASP-183
Turner, Oliver D.; Anderson, D. R.; Barkaoui, K. et al

in Monthly Notices of the Royal Astronomical Society (2019), 485

We present the discovery of three transiting planets from the WASP survey, two hot-Jupiters: WASP-177 b (˜0.5 M[SUB]Jup[/SUB], ˜1.6 R[SUB]Jup[/SUB]) in a 3.07-d orbit of a V = 12.6 K2 star, WASP-183 b (˜0 ... [more ▼]

We present the discovery of three transiting planets from the WASP survey, two hot-Jupiters: WASP-177 b (˜0.5 M[SUB]Jup[/SUB], ˜1.6 R[SUB]Jup[/SUB]) in a 3.07-d orbit of a V = 12.6 K2 star, WASP-183 b (˜0.5 M[SUB]Jup[/SUB], ˜1.5 R[SUB]Jup[/SUB]) in a 4.11-d orbit of a V = 12.8 G9/K0 star; and one hot-Saturn planet WASP-181 b (˜0.3 M[SUB]Jup[/SUB], ˜1.2 R[SUB]Jup[/SUB]) in a 4.52-d orbit of a V = 12.9 G2 star. Each planet is close to the upper bound of mass-radius space and has a scaled semimajor axis, a/R[SUB]*[/SUB], between 9.6 and 12.1. These lie in the transition between systems that tend to be in orbits that are well aligned with their host-star's spin and those that show a higher dispersion. [less ▲]

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See detailThe enigmatic binary system HD 5980
Hillier, D. John; Koenigsberger, Gloria; Nazé, Yaël ULiege et al

in Monthly Notices of the Royal Astronomical Society (2019), 486

The Small Magellanic Cloud multiple system HD 5980 contains a luminous blue variable (LBV) that underwent a major eruption in 1994, and whose current spectrum is that of a hydrogen-rich Wolf-Rayet (WR ... [more ▼]

The Small Magellanic Cloud multiple system HD 5980 contains a luminous blue variable (LBV) that underwent a major eruption in 1994, and whose current spectrum is that of a hydrogen-rich Wolf-Rayet (WR) star. Since the eruption, the wind mass-loss rate has been declining while wind speeds have been steadily increasing. Observations obtained in 2014 when Star A (the LBV) eclipses Star B indicate that the fitted mass-loss rate and luminosity have reached the lowest values ever determined for such spectra: \dot{M} = 4.5 × 10[SUP]-5[/SUP]M_⊙ yr^{-1}, L = 1.7 × 10[SUP]6 [/SUP]L[SUB]⊙[/SUB]. In addition, the radius of the LBV's continuum-emitting region is similar to that derived from the eclipse light curves of the late 1970s. Hence, it appears to have attained a similar `low' state to that of the late 1970s. While a good fit to the emission spectrum is obtained using a CMFGEN model, there are discrepancies in the UV. In particular, the extent of the observed absorption profiles is ˜1000 km s[SUP]-1[/SUP] greater than predicted by the emission-line intensities. Further, HST UV observations obtained in 2016, when Star A is eclipsed by Star B, show unusual P Cygni profiles that are not easily explained. Surprisingly the 2016 emission-line spectrum is similar to that at the opposite eclipse obtained in 2014. The complex UV profiles are likely to arise as a consequence of the dynamics of the wind-wind collision and radiative braking, both of which will cause significant departures from spherical symmetry, and have a strong orbital phase dependence. However, other scenarios, such as intrinsically aspherical winds, cannot be ruled out. [less ▲]

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See detailSTIM map: detection map for exoplanets imaging beyond asymptotic Gaussian residual speckle noise
Pairet, Benoît; Cantalloube, Faustine; Gomez Gonzalez, Carlos A. et al

in Monthly Notices of the Royal Astronomical Society (2019), 487

Direct imaging of exoplanets is a challenging task as it requires to reach a high contrast at very close separation to the star. Today, the main limitation in the high-contrast images is the quasi-static ... [more ▼]

Direct imaging of exoplanets is a challenging task as it requires to reach a high contrast at very close separation to the star. Today, the main limitation in the high-contrast images is the quasi-static speckles that are created by residual instrumental aberrations. They have the same angular size as planetary companions and are often brighter, hence hindering our capability to detect exoplanets. Dedicated observation strategies and signal processing techniques are necessary to disentangle these speckles from planetary signals. The output of these methods is a detection map in which the value of each pixel is related to a probability of presence of a planetary signal. The detection map found in the literature relies on the assumption that the residual noise is Gaussian. However, this is known to lead to higher false positive rates, especially close to the star. In this paper, we re-visit the notion of detection map by analysing the speckle noise distribution, namely the Modified Rician distribution. We use non-asymptotic analysis of the sum of random variables to show that the tail of the distribution of the residual noise decays as an exponential distribution, hence explaining the high false detection rate obtained with the Gaussian assumption. From this analysis, we introduce a novel time domain detection map and we demonstrate its capabilities and the relevance of our approach through experiments on real data. We also provide an empirical rule to determine detection threshold providing a good trade-off between true positive and false positive rates for exoplanet detection. [less ▲]

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See detailOGLE-2014-BLG-1186: gravitational microlensing providing evidence for a planet orbiting the foreground star or for a close binary source?
Dominik, M.; Bachelet, E.; Bozza, V. et al

in Monthly Notices of the Royal Astronomical Society (2019), 484

Discussing the particularly long gravitational microlensing event OGLE-2014-BLG-1186 with a time-scale t[SUB]E[/SUB] ˜ 300 d, we present a methodology for identifying the nature of localised deviations ... [more ▼]

Discussing the particularly long gravitational microlensing event OGLE-2014-BLG-1186 with a time-scale t[SUB]E[/SUB] ˜ 300 d, we present a methodology for identifying the nature of localised deviations from single-lens point-source light curves, which ensures that (1) the claimed signal is substantially above the noise floor, (2) the inferred properties are robustly determined and their estimation is not subject to confusion with systematic noise in the photometry, (3) alternative viable solutions within the model framework are not missed. Annual parallax and binarity could be separated and robustly measured from the wing and the peak data, respectively. We find matching model light curves that involve either a binary lens or a binary source, and discover hitherto unknown model ambiguities. Our binary-lens models indicate a planet of mass M[SUB]2[/SUB] = (45 ± 9) M[SUB]⊕[/SUB], orbiting a star of mass M[SUB]1[/SUB] = (0.35 ± 0.06) M[SUB]⊙[/SUB], located at a distance D[SUB]L[/SUB] = (1.7 ± 0.3) kpc from Earth, whereas our binary-source models suggest a brown-dwarf lens of M = (0.046 ± 0.007) M[SUB]⊙[/SUB], located at a distance D[SUB]L[/SUB] = (5.7 ± 0.9) kpc, with the source potentially being a (partially) eclipsing binary involving stars predicted to be of similar colour given the ratios between the luminosities and radii. Further observations might resolve the ambiguity in the interpretation in favour of either a lens or a source binary. We experienced that close binary source stars pose a challenge for claiming the detection of planets by microlensing in events where the source passes very close to the lens star hosting the planet. [less ▲]

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See detailH0LiCOW - IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant
Birrer, S.; Treu, T.; Rusu, C. E. et al

in Monthly Notices of the Royal Astronomical Society (2019), 484

We present a blind time-delay strong lensing (TDSL) cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 . We combine the relative time delay between the quasar images, Hubble Space Telescope ... [more ▼]

We present a blind time-delay strong lensing (TDSL) cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 . We combine the relative time delay between the quasar images, Hubble Space Telescope imaging, the Keck stellar velocity dispersion of the lensing galaxy, and wide-field photometric and spectroscopic data of the field to constrain two angular diameter distance relations. The combined analysis is performed by forward modelling the individual data sets through a Bayesian hierarchical framework, and it is kept blind until the very end to prevent experimenter bias. After unblinding, the inferred distances imply a Hubble constant H[SUB]0[/SUB] = 68.8^{+5.4}_{-5.1} km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP], assuming a flat Λ cold dark matter cosmology with uniform prior on Ω[SUB]m[/SUB] in [0.05, 0.5]. The precision of our cosmographic measurement with the doubly imaged quasar SDSS 1206+4332 is comparable with those of quadruply imaged quasars and opens the path to perform on selected doubles the same analysis as anticipated for quads. Our analysis is based on a completely independent lensing code than our previous three H0LiCOW systems and the new measurement is fully consistent with those. We provide the analysis scripts paired with the publicly available software to facilitate independent analysis (footnote with link to www.h0licow.org). The consistency between blind measurements with independent codes provides an important sanity check on lens modelling systematics. By combining the likelihoods of the four systems under the same prior, we obtain H[SUB]0[/SUB] = 72.5^{+2.1}_{-2.3} km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP]. This measurement is independent of the distance ladder and other cosmological probes. [less ▲]

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See detailExtreme resonance line profile variations in the ultraviolet spectra of NGC 1624-2: probing the giant magnetosphere of the most strongly magnetized known O-type star
David-Uraz, A.; Erba, C.; Petit, V. et al

in Monthly Notices of the Royal Astronomical Society (2019), 483

In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the ... [more ▼]

In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the variability of its wind-sensitive resonance lines, comparing it to that of other known magnetic O stars. In particular, the observed variations in the profiles of the C IV and Si IV doublets between low state and high state are the largest observed in any magnetic O-type star, consistent with the expected properties of NGC 1624-2's magnetosphere. We also observe a redshifted absorption component in the low state, a feature not seen in most stars. We present preliminary modelling efforts based on the Analytic Dynamical Magnetosphere (ADM) formalism, demonstrating the necessity of using non-spherically symmetric models to determine wind/magnetospheric properties of magnetic O stars. [less ▲]

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See detailA remarkable change of the spectrum of the magnetic Of?p star HD 148937 reveals evidence of an eccentric, high-mass binary
Wade, G. A.; Smoker, J. V.; Evans, C. J. et al

in Monthly Notices of the Royal Astronomical Society (2019), 483

We report new spectroscopic observations of the magnetic Of?p star HD 148937 obtained since 2015 that differ qualitatively from its extensive historical record of weak, periodic spectral variations. This ... [more ▼]

We report new spectroscopic observations of the magnetic Of?p star HD 148937 obtained since 2015 that differ qualitatively from its extensive historical record of weak, periodic spectral variations. This remarkable behaviour represents clear evidence for an unprecedented change in the character of variability of the star. In this paper, we describe the new spectral properties and compare them to the previous line profiles. Based on measurements of the radial velocities of the C III/N III emission lines near 4640 Å and the C IV absorption lines near 5800 Å, we infer that HD 148937 is likely a high-mass, double-lined spectroscopic binary. Combining the spectroscopic orbit with an archival interferometric measurement of the apparent separation of the equal brightness components, we tentatively conclude that HD 148937 consists of two O-type stars with masses of approximately 34 and 49 M[SUB]⊙[/SUB], orbiting in an eccentric (e = 0.75), long-period (P[SUB]orb[/SUB] ˜ 26 yr) orbit. We discuss the potential relationship of the binary system to the peculiar properties of HD 148937, and propose future observations to refine the orbital and stellar properties. [less ▲]

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See detailA discontinuity in the Teff-radius relation of M-dwarfs
Rabus, Markus; Lachaume, Régis; Jordán, Andrés et al

in Monthly Notices of the Royal Astronomical Society (2019)

We report on 13 new high-precision measurements of stellar diameters for low-mass dwarfs obtained by means of near-infrared long-baseline interferometry with PIONIER at the Very Large Telescope ... [more ▼]

We report on 13 new high-precision measurements of stellar diameters for low-mass dwarfs obtained by means of near-infrared long-baseline interferometry with PIONIER at the Very Large Telescope Interferometer. Together with accurate parallaxes from Gaia DR2, these measurements provide precise estimates for their linear radii, effective temperatures, masses, and luminosities. This allows us to refine the effective temperature scale, in particular towards the coolest M-dwarfs. We measure for late-type stars with enhanced metallicity slightly inflated radii, whereas for stars with decreased metallicity we measure smaller radii. We further show that Gaia DR2 effective temperatures for M-dwarfs are underestimated by ˜ 8.2 per cent and give an empirical M[SUB]G[/SUB]-T[SUB]eff[/SUB] relation which is better suited for M-dwarfs with T[SUB]eff[/SUB] between 2600 and 4000 K. Most importantly, we are able to observationally identify a discontinuity in the T[SUB]eff[/SUB]-radius plane, which is likely due to the transition from partially convective M-dwarfs to the fully convective regime. We found this transition to happen between 3200 K and 3340 K, or equivalently for stars with masses {≈ } 0.23 M_{⊙}. We find that in this transition region the stellar radii are in the range from 0.18 to 0.42 R[SUB]⊙[/SUB] for similar stellar effective temperatures. [less ▲]

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See detailMean density inversions for red giants and red clump stars
Buldgen, Gaël ULiege; Rendle, B.; Sonoi, T. et al

in Monthly Notices of the Royal Astronomical Society (2019), 482(2), 2305-2319

Since the CoRoT and Kepler missions, the availability of high-quality seismic spectra for red giants has made them the standard clocks and rulers for Galactic Archeology. With the expected excellent data ... [more ▼]

Since the CoRoT and Kepler missions, the availability of high-quality seismic spectra for red giants has made them the standard clocks and rulers for Galactic Archeology. With the expected excellent data from the TESS and PLATO missions, red giants will again play a key role in Galactic studies and stellar physics, thanks to the precise masses and radii determined by asteroseismology. The determination of these quantities is often based on so-called scaling laws, which have been used extensively for main-sequence stars. We show how the SOLA inversion technique can provide robust determinations of the mean density of red giants within 1 per cent of the real value, using only radial oscillations. Combined with radii determinations from Gaia of around 2 per cent precision, this approach provides robust, less model-dependent masses with an error lower than 10 per cent. It will improve age determinations, helping to accurately dissect the Galactic structure and history. We present results on artificial data of standard models, models including an extended atmosphere from averaged 3D simulations and non-adiabatic frequency calculations to test surface effects, and on eclipsing binaries. We show that the inversions provide very robust mean density estimates, using at best seismic information. However, we also show that a distinction between red-giant branch and red-clump stars is required to determine a reliable estimate of the mean density. The stability of the inversion enables an implementation in automated pipelines, making it suitable for large samples of stars. [less ▲]

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See detailNew transiting hot Jupiters discovered by WASP-South, Euler/CORALIE, and TRAPPIST-South
Hellier, Coel; Anderson, D. R.; Bouchy, F. et al

in Monthly Notices of the Royal Astronomical Society (2019), 482

We report the discovery of eight hot-Jupiter exoplanets from the WASP-South transit survey. WASP-144b has a mass of 0.44 M[SUB]Jup[/SUB], a radius of 0.85 R[SUB]Jup[/SUB], and is in a 2.27-d orbit around ... [more ▼]

We report the discovery of eight hot-Jupiter exoplanets from the WASP-South transit survey. WASP-144b has a mass of 0.44 M[SUB]Jup[/SUB], a radius of 0.85 R[SUB]Jup[/SUB], and is in a 2.27-d orbit around a V = 12.9, K2 star which shows a 21-d rotational modulation. WASP-145Ab is a 0.89 M[SUB]Jup[/SUB] planet in a 1.77-d orbit with a grazing transit. The host is a V = 11.5, K2 star with a companion 5 arcsec away and 1.4 mag fainter. WASP-158b is a relatively massive planet at 2.8 M[SUB]Jup[/SUB] with a radius of 1.1 R[SUB]Jup[/SUB] and a 3.66-d orbit. It transits a V = 12.1, F6 star. WASP-159b is a bloated hot Jupiter (1.4 R[SUB]Jup[/SUB] and 0.55 M[SUB]Jup[/SUB]) in a 3.8-d orbit around a V = 12.9, F9 star. WASP-162b is a massive planet in a relatively long and highly eccentric orbit (5.2 M[SUB]Jup[/SUB], P = 9.6 d, e = 0.43). It transits a V = 12.2, K0 star. WASP-168b is a bloated hot Jupiter (0.42 M[SUB]Jup[/SUB]; 1.5 R[SUB]Jup[/SUB]) in a 4.15-d orbit with a grazing transit. The host is a V = 12.1, F9 star. WASP-172b is a bloated hot Jupiter (0.5 M[SUB]Jup[/SUB]; 1.6 R[SUB]Jup[/SUB]) in a 5.48-d orbit around a V = 11.0, F1 star. WASP-173Ab is a massive planet (3.7 M[SUB]Jup[/SUB]) with a 1.2 R[SUB]Jup[/SUB] radius in a circular orbit with a period of 1.39 d. The host is a V = 11.3, G3 star, being the brighter component of the double-star system WDS23366 - 3437, with a companion 6 arcsec away and 0.8 mag fainter. One of the two stars shows a rotational modulation of 7.9 d. [less ▲]

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See detailConstraining the microlensing effect on time delays with a new time-delay prediction model in H0 measurements
Chen, Geoff C.-F.; Chan, James H. H.; Bonvin, Vivien et al

in Monthly Notices of the Royal Astronomical Society (2018), 481

Time-delay strong lensing provides a unique way to directly measure the Hubble constant (H0). The precision of the H0measurement depends on the uncertainties in the time-delay measurements, the mass ... [more ▼]

Time-delay strong lensing provides a unique way to directly measure the Hubble constant (H0). The precision of the H0measurement depends on the uncertainties in the time-delay measurements, the mass distribution of the main deflector(s), and the mass distribution along the line of sight. Tie & Kochanek have proposed a new microlensing effect on time delays based on differential magnification of the coherent accretion disc variability of the lensed quasar. If real, this effect could significantly broaden the uncertainty on the time-delay measurements by up to 30 per cent for lens systems such as PG 1115+080, which have relatively short time delays and monitoring over several different epochs. In this paper we develop a new technique that uses the cosmological time-delay ratios and simulated microlensing maps within a Bayesian framework in order to limit the allowed combinations of microlensing delays and thus to lessen the uncertainties due to the proposed effect. We show that, under the assumption of Tie & Kochanek, the uncertainty on the time-delay distance (D∆t, which is proportional to 1/H0) of the short time-delay (18 d) lens, PG 1115+080, increases from 7 per cent to ̃10 per cent by simultaneously fitting the three time-delay measurements from the three different data sets across 20 yr, while in the case of the long time-delay (̃90 d) lens, the microlensing effect on time delays is negligible as the uncertainty on D[SUB]∆t[/SUB] of RXJ 1131-1231 only increases from ̃2.5 per cent to 2.6 per cent. [less ▲]

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See detailDiscovery of WASP-174b: Doppler tomography of a near-grazing transit
Temple, L. Y.; Hellier, C.; Almleaky, Y. et al

in Monthly Notices of the Royal Astronomical Society (2018), 480

We report the discovery and tomographic detection of WASP-174b, a planet with a near-grazing transit on a 4.23-d orbit around a V= 11.9, F6V star with [Fe/H] = 0.09 ± 0.09. The planet is in a moderately ... [more ▼]

We report the discovery and tomographic detection of WASP-174b, a planet with a near-grazing transit on a 4.23-d orbit around a V= 11.9, F6V star with [Fe/H] = 0.09 ± 0.09. The planet is in a moderately misaligned orbit with a sky-projected spin-orbit angle of λ = 31° ± 1°. This is in agreement with the known tendency for orbits around hotter stars to be misaligned. Owing to the grazing transit, the planet's radius is uncertain with a possible range of 0.8-1.8 R[SUB]Jup[/SUB]. The planet's mass has an upper limit of 1.3 M[SUB]Jup[/SUB]. WASP-174 is the faintest hot-Jupiter system so far confirmed by tomographic means. [less ▲]

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See detailWASP-147b, 160Bb, 164b and 165b: two hot Saturns and two Jupiters, including two planets with metal-rich hosts
Lendl, M.; Anderson, D. R.; Bonfanti, Andrea ULiege et al

in Monthly Notices of the Royal Astronomical Society (2018)

We report the discovery of four transiting hot Jupiters, WASP-147, WASP-160B, WASP-164 and WASP-165 from the WASP survey. WASP-147b is a near Saturn-mass (M[SUB]P[/SUB] = 0.28M[SUB]J[/SUB]) object with a ... [more ▼]

We report the discovery of four transiting hot Jupiters, WASP-147, WASP-160B, WASP-164 and WASP-165 from the WASP survey. WASP-147b is a near Saturn-mass (M[SUB]P[/SUB] = 0.28M[SUB]J[/SUB]) object with a radius of 1.11 R[SUB]J[/SUB] orbiting a G4 star with a period of 4.6 d. WASP-160Bb has a mass and radius (M[SUB]p[/SUB] = 0.28 M[SUB]J[/SUB], R[SUB]p[/SUB] = 1.09 R[SUB]J[/SUB]) near-identical to WASP-147b, but is less irradiated, orbiting a metal-rich ([Fe/H][SUB]*[/SUB] = 0.27) K0 star with a period of 3.8 d. WASP-160B is part of a near equal-mass visual binary with an on-sky separation of 28.5 arcsec. WASP-164b is a more massive (M[SUB]P[/SUB] = 2.13 M[SUB]J[/SUB], R[SUB]p[/SUB] = 1.13 R[SUB]J[/SUB]) hot Jupiter, orbiting a G2 star on a close-in (P = 1.8 d), but tidally stable orbit. WASP-165b is a classical (M[SUB]p[/SUB] = 0.66 M[SUB]J[/SUB], R[SUB]P[/SUB] = 1.26 R[SUB]J[/SUB]) hot Jupiter in a 3.5 d period orbit around a metal-rich ([Fe/H][SUB]*[/SUB] = 0.33) star. WASP-147b and WASP-160Bb are promising targets for atmospheric characterization through transmission spectroscopy, while WASP-164b presents a good target for emission spectroscopy. [less ▲]

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See detailA cosmology-independent calibration of type Ia supernovae data
Hauret, Clémentine ULiege; Magain, Pierre ULiege; Biernaux, Judith ULiege

in Monthly Notices of the Royal Astronomical Society (2018), 479(3), 3996-4003

Recently, the common methodology used to transform type Ia supernovae (SNe Ia) into genuine standard candles has been suffering criticism. Indeed, it assumes a par- ticular cosmological model (namely the ... [more ▼]

Recently, the common methodology used to transform type Ia supernovae (SNe Ia) into genuine standard candles has been suffering criticism. Indeed, it assumes a par- ticular cosmological model (namely the flat LambdaCDM) to calibrate the standardisation corrections parameters, i.e. the dependency of the supernova peak absolute magnitude on its colour, post-maximum decline rate and host galaxy mass. As a result, this as- sumption could make the data compliant to the assumed cosmology and thus nullify all works previously conducted on model comparison. In this work, we verify the viability of these hypotheses by developing a cosmology-independent approach to standardise SNe Ia data from the recent JLA compilation. Our resulting corrections turn out to be very close to the LambdaCDM-based corrections. Therefore, even if a LambdaCDM-based calibra- tion is questionable from a theoretical point of view, the potential compliance of SNe Ia data does not happen in practice for the JLA compilation. Previous works of model comparison based on these data do not have to be called into question. However, as this cosmology-independent standardisation method has the same degree of complex- ity than the model-dependent one, it is worth using it in future works, especially if smaller samples are considered, such as the superluminous type Ic supernovae. [less ▲]

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See detailWASP-128b: a transiting brown dwarf in the dynamical-tide regime
Hodžić, Vedad; Triaud, Amaury H. M. J.; Anderson, David R. et al

in Monthly Notices of the Royal Astronomical Society (2018)

Massive companions in close orbits around G dwarfs are thought to undergo rapid orbital decay due to runaway tidal dissipation. We report here the discovery of WASP-128b, a brown dwarf discovered by the ... [more ▼]

Massive companions in close orbits around G dwarfs are thought to undergo rapid orbital decay due to runaway tidal dissipation. We report here the discovery of WASP-128b, a brown dwarf discovered by the WASP survey transiting a G0V host on a 2.2 d orbit, where the measured stellar rotation rate places the companion in a regime where tidal interaction is dominated by dynamical tides. Under the assumption of dynamical equilibrium, we derive a value of the stellar tidal quality factor log {Q_\star ^' }} = {6.96 ± 0.19}. A combined analysis of ground-based photometry and high-resolution spectroscopy reveals a mass and radius of the host, M[SUB]⋆[/SUB] = 1.16 ± 0.04M[SUB]⊙[/SUB], R[SUB]⋆[/SUB] = 1.16 ± 0.02R[SUB]⊙[/SUB], and for the companion, M[SUB]b[/SUB] = 37.5 ± 0.8Mj, R[SUB]b[/SUB] = 0.94 ± 0.02Rj, placing WASP-128b in the driest parts of the brown dwarf desert, and suggesting a mild inflation for its age. We estimate a remaining lifetime for WASP-128b similar to that of some ultra-short period massive hot Jupiters, and note it may be a propitious candidate for measuring orbital decay and testing tidal theories. [less ▲]

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See detailH0LiCOW VIII. A weak-lensing measurement of the external convergence in the field of the lensed quasar HE 0435-1223
Tihhonova, O.; Courbin, F.; Harvey, D. et al

in Monthly Notices of the Royal Astronomical Society (2018), 477

We present a weak gravitational lensing measurement of the external convergence along the line of sight to the quadruply lensed quasar HE 0435-1223. Using deep r-band images from Subaru Suprime Cam, we ... [more ▼]

We present a weak gravitational lensing measurement of the external convergence along the line of sight to the quadruply lensed quasar HE 0435-1223. Using deep r-band images from Subaru Suprime Cam, we observe galaxies down to a 3σ limiting magnitude of ˜26 mag resulting in a source galaxy density of 14 galaxies per square arcminute after redshift-based cuts. Using an inpainting technique and multiscale entropy filtering algorithm, we find that the region in close proximity to the lens has an estimated external convergence of κ =-0.012^{+0.020}_{-0.013} and is hence marginally underdense. We also rule out the presence of any halo with a mass greater than M[SUB]vir[/SUB] = 1.6 × 10[SUP]14[/SUP]h[SUP]-1[/SUP]M[SUB]⊙[/SUB] (68 per cent confidence limit). Our results, consistent with previous studies of this lens, confirm that the intervening mass along the line of sight to HE 0435-1223 does not affect significantly the cosmological results inferred from the time-delay measurements of that specific object. [less ▲]

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See detailHigh-contrast imaging of HD 163296 with the Keck/NIRC2 L'-band vortex coronograph
Guidi, G.; Ruane, G.; Williams, J. P. et al

in Monthly Notices of the Royal Astronomical Society (2018), 479

We present observations of the nearby (D~100 pc) Herbig star HD 163296 taken with the vortex coronograph at Keck/NIRC2 in the L' band (3.7 μm) to search for planetary mass companions in the ringed disc ... [more ▼]

We present observations of the nearby (D~100 pc) Herbig star HD 163296 taken with the vortex coronograph at Keck/NIRC2 in the L' band (3.7 μm) to search for planetary mass companions in the ringed disc surrounding this pre-main-sequence star. The images reveal an arc-like region of scattered light from the disc surface layers that is likely associated with the first bright ring detected with ALMA in the λ = 1.3mm dust continuum at ~65 au. We also detect a point-like source at ~0.5 arcsec projected separation in the north-east direction, close to the inner edge of the second gap in the millimetre images. Comparing the point source photometry with the atmospheric emission models of non-accreting giant planets, we obtain a mass of 6-7 MJ for a putative protoplanet, assuming a system age of 5 Myr. Based on the contrast at a 95 per cent level of completeness calculated on the emission-free regions of our images, we set upper limits for the masses of giant planets of 8-15 MJ, 4.5-6.5 MJ, and 2.5-4.0MJ at the locations of the first, second, and third gap in the millimetre dust continuum, respectively. Further deep, high-resolution thermal IR imaging of the HD 163296 system are warranted to confirm the presence and nature of the point source and to better understand the structure of the dust disc. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. [less ▲]

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