@article{11619,
  abstract     = {We report on the confirmation and mass determination of π Men c, the first transiting planet discovered by NASA’s TESS space mission. π Men is a naked-eye (V = 5.65 mag), quiet G0 V star that was previously known to host a sub-stellar companion (π Men b) on a longperiod (Porb = 2091 days), eccentric (e = 0.64) orbit. Using TESS time-series photometry, combined with Gaia data, published UCLES at AAT Doppler measurements, and archival HARPS at ESO-3.6m radial velocities, we found that π Men c is a close-in planet with an orbital period of Porb = 6.27 days, a mass of Mc = 4.52 ± 0.81 M⊕, and a radius of Rc = 2.06 ± 0.03 R⊕. Based on the planet’s orbital period and size, π Men c is a super-Earth located at, or close to, the radius gap, while its mass and bulk density suggest it may have held on to a significant atmosphere. Because of the brightness of the host star, this system is highly suitable for a wide range of further studies to characterize the planetary atmosphere and dynamical properties. We also performed an asteroseismic analysis of the TESS data and detected a hint of power excess consistent with the seismic values expected for this star, although this result depends on the photometric aperture used to extract the light curve. This marginal detection is expected from pre-launch simulations hinting at the asteroseismic potential of the TESS mission for longer, multi-sector observations and/or for more evolved bright stars.},
  author       = {Gandolfi, D. and Barragán, O. and Livingston, J. H. and Fridlund, M. and Justesen, A. B. and Redfield, S. and Fossati, L. and Mathur, S. and Grziwa, S. and Cabrera, J. and García, R. A. and Persson, C. M. and Van Eylen, V. and Hatzes, A. P. and Hidalgo, D. and Albrecht, S. and Bugnet, Lisa Annabelle and Cochran, W. D. and Csizmadia, Sz. and Deeg, H. and Eigmüller, Ph. and Endl, M. and Erikson, A. and Esposito, M. and Guenther, E. and Korth, J. and Luque, R. and Montañes Rodríguez, P. and Nespral, D. and Nowak, G. and Pätzold, M. and Prieto-Arranz, J.},
  issn         = {1432-0746},
  journal      = {Astronomy & Astrophysics},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, planetary systems / planets and satellites, detection / planets and satellites, fundamental parameters / planets and satellites, terrestrial planets / stars, fundamental parameters},
  publisher    = {EDP Sciences},
  title        = {{TESS’s first planet: A super-Earth transiting the naked-eye star π Mensae}},
  doi          = {10.1051/0004-6361/201834289},
  volume       = {619},
  year         = {2018},
}

@unpublished{11631,
  abstract     = {The recently launched NASA Transiting Exoplanet Survey Satellite (TESS) mission is going to collect lightcurves for a few hundred million of stars and we expect to increase the number of pulsating stars to analyze compared to the few thousand stars observed by the CoRoT, Kepler and K2 missions. However, most of the TESS targets have not yet been properly classified and characterized. In order to improve the analysis of the TESS data, it is crucial to determine the type of stellar pulsations in a timely manner. We propose an automatic method to classify stars attending to their pulsation properties, in particular, to identify solar-like pulsators among all TESS targets. It relies on the use of the global amount of power contained in the power spectrum (already known as the FliPer method) as a key parameter, along with
the effective temperature, to feed into a machine learning classifier. Our study, based on TESS simulated datasets, shows that we are able to classify pulsators with a 98% accuracy.},
  author       = {Bugnet, Lisa Annabelle and García, R. A. and Davies, G. R. and Mathur, S. and Hall, O. J. and Rendle, B. M.},
  booktitle    = {arXiv},
  keywords     = {asteroseismology - methods, data analysis - stars, oscillations},
  title        = {{FliPer: Classifying TESS pulsating stars}},
  doi          = {10.48550/arXiv.1811.12140},
  year         = {2018},
}

@article{11518,
  abstract     = {We present spectroscopic follow-up observations of CR7 with ALMA, targeted at constraining the infrared (IR) continuum and [C II]158 mm line-emission at high spatial resolution matched to the HST/WFC3 imaging. CR7 is a luminous Lyα emitting galaxy at z = 6.6 that consists of three separated UV-continuum components. Our observations reveal several well-separated components of [C II] emission. The two most luminous components in [C II] coincide with the brightest UV components (A and B), blueshifted by »150 km s−1 with respect to the
peak of Lyα emission. Other [C II] components are observed close to UV clumps B and C and are blueshifted by »300 and ≈80 km s−1 with respect to the systemic redshift. We do not detect FIR continuum emission due to dust with a 3σ limiting luminosity LIR T L d 35 K 3.1 10 = <´ 10 ( ) . This allows us to mitigate uncertainties in the dust-corrected SFR and derive SFRs for the three UV clumps A, B, and C of 28, 5, and 7 M yr−1. All clumps have [C II] luminosities consistent within the scatter observed in the local relation between SFR and L[ ] C II , implying that strong Lyα emission does not necessarily anti-correlate with [C II] luminosity. Combining
our measurements with the literature, we show that galaxies with blue UV slopes have weaker [C II] emission at fixed SFR, potentially due to their lower metallicities and/or higher photoionization. Comparison with hydrodynamical simulations suggests that CR7ʼs clumps have metallicities of 0.1 Z Z 0.2 < < . The observed ISM structure of CR7 indicates that we are likely witnessing the build up of a central galaxy in the early universe through complex accretion of satellites.},
  author       = {Matthee, Jorryt J and Sobral, D. and Boone, F. and Röttgering, H. and Schaerer, D. and Girard, M. and Pallottini, A. and Vallini, L. and Ferrara, A. and Darvish, B. and Mobasher, B.},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, dark ages, reionization, first stars – galaxies: formation – galaxies: high-redshift – galaxies: ISM – galaxies: kinematics and dynamics},
  number       = {2},
  publisher    = {IOP Publishing},
  title        = {{ALMA reveals metals yet no dust within multiple components in CR7}},
  doi          = {10.3847/1538-4357/aa9931},
  volume       = {851},
  year         = {2017},
}

@article{11564,
  abstract     = {We study the production rate of ionizing photons of a sample of 588 Hα emitters (HAEs) and 160 Lyman-α emitters (LAEs) at z = 2.2 in the COSMOS field in order to assess the implied emissivity from galaxies, based on their ultraviolet (UV) luminosity. By exploring the rest-frame Lyman Continuum (LyC) with GALEX/NUV data, we find fesc < 2.8 (6.4) per cent through median (mean) stacking. By combining the Hα luminosity density with intergalactic medium emissivity measurements from absorption studies, we find a globally averaged 〈fesc〉 of 5.9+14.5−4.2 per cent at z = 2.2 if we assume HAEs are the only source of ionizing photons. We find similarly low values of the global 〈fesc〉 at z ≈ 3–5, also ruling out a high 〈fesc〉 at z < 5. These low escape fractions allow us to measure ξion, the number of produced ionizing photons per unit UV luminosity, and investigate how this depends on galaxy properties. We find a typical ξion ≈ 1024.77 ± 0.04 Hz erg−1 for HAEs and ξion ≈ 1025.14 ± 0.09 Hz erg−1 for LAEs. LAEs and low-mass HAEs at z = 2.2 show similar values of ξion as typically assumed in the reionization era, while the typical HAE is three times less ionizing. Due to an increasing ξion with increasing EW(Hα), ξion likely increases with redshift. This evolution alone is fully in line with the observed evolution of ξion between z ≈ 2 and 5, indicating a typical value of ξion ≈ 1025.4 Hz erg−1 in the reionization era.},
  author       = {Matthee, Jorryt J and Sobral, David and Best, Philip and Khostovan, Ali Ahmad and Oteo, Iván and Bouwens, Rychard and Röttgering, Huub},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: high-redshift, cosmology: observations, dark ages, reionization, first stars},
  number       = {3},
  pages        = {3637--3655},
  publisher    = {Oxford University Press},
  title        = {{The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution}},
  doi          = {10.1093/mnras/stw2973},
  volume       = {465},
  year         = {2017},
}

@article{11572,
  abstract     = {We present spectroscopic follow-up of candidate luminous Ly α emitters (LAEs) at z = 5.7–6.6 in the SA22 field with VLT/X-SHOOTER. We confirm two new luminous LAEs at z = 5.676 (SR6) and z = 6.532 (VR7), and also present HST follow-up of both sources. These sources have luminosities LLy α ≈ 3 × 1043 erg s−1, very high rest-frame equivalent widths of EW0 ≳ 200 Å and narrow Ly α lines (200–340 km s−1). VR7 is the most UV-luminous LAE at z > 6.5, with M1500 = −22.5, even brighter in the UV than CR7. Besides Ly α, we do not detect any other rest-frame UV lines in the spectra of SR6 and VR7, and argue that rest-frame UV lines are easier to observe in bright galaxies with low Ly α equivalent widths. We confirm that Ly α line widths increase with Ly α luminosity at z = 5.7, while there are indications that Ly α lines of faint LAEs become broader at z = 6.6, potentially due to reionization. We find a large spread of up to 3 dex in UV luminosity for >L⋆ LAEs, but find that the Ly α luminosity of the brightest LAEs is strongly related to UV luminosity at z = 6.6. Under basic assumptions, we find that several LAEs at z ≈ 6–7 have Ly α escape fractions ≳ 100  per cent, indicating bursty star formation histories, alternative Ly α production mechanisms, or dust attenuating Ly α emission differently than UV emission. Finally, we present a method to compute ξion, the production efficiency of ionizing photons, and find that LAEs at z ≈ 6–7 have high values of log10(ξion/Hz erg−1) ≈ 25.51 ± 0.09 that may alleviate the need for high Lyman-Continuum escape fractions required for reionization.},
  author       = {Matthee, Jorryt J and Sobral, David and Darvish, Behnam and Santos, Sérgio and Mobasher, Bahram and Paulino-Afonso, Ana and Röttgering, Huub and Alegre, Lara},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution – galaxies: high-redshift, dark ages, reionization, first stars, cosmology: observations},
  number       = {1},
  pages        = {772--787},
  publisher    = {Oxford University Press},
  title        = {{Spectroscopic properties of luminous Ly α emitters at z ≈ 6–7 and comparison to the Lyman-break population}},
  doi          = {10.1093/mnras/stx2061},
  volume       = {472},
  year         = {2017},
}

@unpublished{11633,
  abstract     = {Our understanding of stars through asteroseismic data analysis is limited by our ability to take advantage of the huge amount of observed stars provided by space missions such as CoRoT, Kepler , K2, and soon TESS and PLATO. Global seismic pipelines provide global stellar parameters such as mass and radius using the mean seismic parameters, as well as the effective temperature. These pipelines are commonly used automatically on thousands of stars observed by K2 for 3 months (and soon TESS for at least ∼ 1 month). However, pipelines are not immune from misidentifying noise peaks and stellar oscillations. Therefore, new validation techniques are required to assess the quality of these results. We present a new metric called FliPer (Flicker in Power), which takes into account the average variability at all measured time scales. The proper calibration of FliPer enables us to obtain good estimations of global stellar parameters such as surface gravity that are robust against the influence of noise peaks and hence are an excellent way to find faults in asteroseismic pipelines.},
  author       = {Bugnet, Lisa Annabelle and Garcia, R. A. and Davies, G. R. and Mathur, S. and Corsaro, E.},
  booktitle    = {arXiv},
  keywords     = {asteroseismology - methods, data analysis - stars, oscillations},
  title        = {{FliPer: Checking the reliability of global seismic parameters from automatic pipelines}},
  doi          = {10.48550/arXiv.1711.02890},
  year         = {2017},
}

@article{11574,
  abstract     = {We present new results from the widest narrow-band survey search for Lyα emitters at z = 5.7, just after reionization. We survey a total of 7 deg2 spread over the COSMOS, UDS and SA22 fields. We find over 11 000 line emitters, out of which 514 are robust Lyα candidates at z = 5.7 within a volume of 6.3 × 106 Mpc3. Our Lyα emitters span a wide range in Lyα luminosities, from faint to bright (LLyα ∼ 1042.5–44 erg s−1) and rest-frame equivalent widths (EW0 ∼ 25–1000 Å) in a single, homogeneous data set. By combining all our fields, we find that the faint end slope of the z = 5.7 Lyα luminosity function is very steep, with α=−2.3+0.4−0.3⁠. We also present an updated z = 6.6 Lyα luminosity function, based on comparable volumes and obtained with the same methods, which we directly compare with that at z = 5.7. We find a significant decline of the number density of faint Lyα emitters from z = 5.7 to 6.6 (by 0.5 ± 0.1 dex), but no evolution at the bright end/no evolution in L*. Faint Lyα emitters at z = 6.6 show much more extended haloes than those at z = 5.7, suggesting that neutral Hydrogen plays an important role, increasing the scattering and leading to observations missing faint Lyα emission within the epoch of reionization. Altogether, our results suggest that we are observing patchy reionization which happens first around the brightest Lyα emitters, allowing the number densities of those sources to remain unaffected by the increase of neutral Hydrogen fraction from z ∼ 5 to 7.},
  author       = {Santos, Sérgio and Sobral, David and Matthee, Jorryt J},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: high-redshift, galaxies: luminosity function, mass function, cosmology: observations, dark ages, reionization, first stars},
  number       = {2},
  pages        = {1678--1691},
  publisher    = {Oxford University Press},
  title        = {{The Lyα luminosity function at z= 5.7–6.6 and the steep drop of the faint end: Implications for reionization}},
  doi          = {10.1093/mnras/stw2076},
  volume       = {463},
  year         = {2016},
}

@article{11575,
  abstract     = {We investigate correlations between different physical properties of star-forming galaxies in the ‘Evolution and Assembly of GaLaxies and their Environments’ (EAGLE) cosmological hydrodynamical simulation suite over the redshift range 0 ≤ z ≤ 4.5. A principal component analysis reveals that neutral gas fraction (fgas,neutral), stellar mass (Mstellar) and star formation rate (SFR) account for most of the variance seen in the population, with galaxies tracing a two-dimensional, nearly flat, surface in the three-dimensional space of fgas, neutral–Mstellar–SFR with little scatter. The location of this plane varies little with redshift, whereas galaxies themselves move along the plane as their fgas, neutral and SFR drop with redshift. The positions of galaxies along the plane are highly correlated with gas metallicity. The metallicity can therefore be robustly predicted from fgas, neutral, or from the Mstellar and SFR. We argue that the appearance of this ‘Fundamental Plane of star formation’ is a consequence of self-regulation, with the plane's curvature set by the dependence of the SFR on gas density and metallicity. We analyse a large compilation of observations spanning the redshift range 0 ≲ z ≲ 3, and find that such a plane is also present in the data. The properties of the observed Fundamental Plane of star formation are in good agreement with EAGLE's predictions.},
  author       = {Lagos, Claudia del P. and Theuns, Tom and Schaye, Joop and Furlong, Michelle and Bower, Richard G. and Schaller, Matthieu and Crain, Robert A. and Trayford, James W. and Matthee, Jorryt J},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics  stars: formation, ISM: evolution, galaxies: evolution, galaxies: formation, galaxies: ISM},
  number       = {3},
  pages        = {2632--2650},
  publisher    = {Oxford University Press},
  title        = {{The Fundamental Plane of star formation in galaxies revealed by the EAGLE hydrodynamical simulations}},
  doi          = {10.1093/mnras/stw717},
  volume       = {459},
  year         = {2016},
}

@article{11519,
  abstract     = {Faint Lyα emitters become increasingly rarer toward the reionization epoch (z ∼ 6–7). However, observations from a very large (∼5 deg2) Lyα narrow-band survey at z = 6.6 show that this is not the case for the most luminous emitters, capable of ionizing their own local bubbles. Here we present follow-up observations of the two most luminous Lyα candidates in the COSMOS field: “MASOSA” and “CR7.” We used X-SHOOTER, SINFONI, and FORS2 on the Very Large Telescope, and DEIMOS on Keck, to confirm both candidates beyond any doubt. We find redshifts of z = 6.541 and z = 6.604 for “MASOSA” and “CR7,” respectively. MASOSA has a strong detection in Lyα with a line width of 386 ± 30 km s−1 (FWHM) and with very high EW0 (>200 Å), but undetected in the continuum, implying very low stellar mass and a likely young, metal-poor stellar population. “CR7,” with an observed Lyα luminosity of 1043.92±0.05 erg s−1 is the most luminous Lyα emitter ever found at z > 6 and is spatially extended (∼16 kpc). “CR7” reveals a narrow Lyα line with 266 ± 15 km s−1 FWHM, being detected in the near-infrared (NIR) (rest-frame UV; β = −2.3 ± 0.1) and in IRAC/Spitzer. We detect a narrow He II 1640 Å emission line (6σ, FWHM = 130 ± 30 km s−1 ) in CR7 which can explain the clear excess seen in the J-band photometry (EW0 ∼ 80 Å). We find no other emission lines from the UV to the NIR in our X-SHOOTER spectra (He II/O III] 1663 Å > 3 and He II/C III] 1908 Å > 2.5). We conclude that CR7 is best explained by a combination of a PopIII-like population, which dominates the rest-frame UV and the nebular emission, and a more normal stellar population, which presumably dominates the mass. Hubble Space Telescope/WFC3 observations show that the light is indeed spatially separated between a very blue component, coincident with Lyα and He II emission, and two red components (∼5 kpc away), which dominate the mass. Our findings are consistent with theoretical predictions of a PopIII wave, with PopIII star formation migrating away from the original sites of star formation.},
  author       = {Sobral, David and Matthee, Jorryt J and Darvish, Behnam and Schaerer, Daniel and Mobasher, Bahram and Röttgering, Huub and Santos, Sérgio and Hemmati, Shoubaneh},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, dark ages, reionization, first stars – early universe – galaxies: evolution},
  number       = {2},
  pages        = {139},
  publisher    = {IOP Publishing},
  title        = {{Evidence for PopIII-like stellar populations in the most luminous Lyα emitters at the epoch of reionisation: Spectroscopic confirmation}},
  doi          = {10.1088/0004-637X/808/2/139},
  volume       = {808},
  year         = {2015},
}

@article{11579,
  abstract     = {CR7 is the brightest z = 6.6 Ly α emitter (LAE) known to date, and spectroscopic follow-up by Sobral et al. suggests that CR7 might host Population (Pop) III stars. We examine this interpretation using cosmological hydrodynamical simulations. Several simulated galaxies show the same ‘Pop III wave’ pattern observed in CR7. However, to reproduce the extreme CR7 Ly α/He II1640 line luminosities (⁠Lα/HeII⁠) a top-heavy initial mass function and a massive ( ≳ 107 M⊙) Pop III burst with age ≲ 2 Myr are required. Assuming that the observed properties of Ly α and He II emission are typical for Pop III, we predict that in the COSMOS/UDS/SA22 fields, 14 out of the 30 LAEs at z = 6.6 with Lα > 1043.3 erg s−1 should also host Pop III stars producing an observable LHeII≳1042.7ergs−1⁠. As an alternate explanation, we explore the possibility that CR7 is instead powered by accretion on to a direct collapse black hole. Our model predicts Lα, LHeII⁠, and X-ray luminosities that are in agreement with the observations. In any case, the observed properties of CR7 indicate that this galaxy is most likely powered by sources formed from pristine gas. We propose that further X-ray observations can distinguish between the two above scenarios.},
  author       = {Pallottini, A. and Ferrara, A. and Pacucci, F. and Gallerani, S. and Salvadori, S. and Schneider, R. and Schaerer, D. and Sobral, D. and Matthee, Jorryt J},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, black hole physics, stars: Population III, galaxies: high-redshift},
  number       = {3},
  pages        = {2465--2470},
  publisher    = {Oxford University Press},
  title        = {{The brightest Lyα emitter: Pop III or black hole?}},
  doi          = {10.1093/mnras/stv1795},
  volume       = {453},
  year         = {2015},
}

@article{11583,
  abstract     = {Candidate galaxies at redshifts of z ∼ 10 are now being found in extremely deep surveys, probing very small areas. As a consequence, candidates are very faint, making spectroscopic confirmation practically impossible. In order to overcome such limitations, we have undertaken the CF-HiZELS survey, which is a large-area, medium-depth near-infrared narrow-band survey targeted at z = 8.8 Lyman α (Lyα) emitters (LAEs) and covering 10 deg2 in part of the SSA22 field with the Canada–France–Hawaii Telescope (CFHT). We surveyed a comoving volume of 4.7 × 106 Mpc3 to a Lyα luminosity limit of 6.3 × 1043舁erg舁s−1. We look for Lyα candidates by applying the following criteria: (i) clear emission-line source, (ii) no optical detections (ugriz from CFHTLS), (iii) no visible detection in the optical stack (ugriz > 27), (iv) visually checked reliable NBJ and J detections and (v) J − K ≤ 0. We compute photometric redshifts and remove a significant amount of dusty lower redshift line-emitters at z ∼ 1.4 or 2.2. A total of 13 Lyα candidates were found, of which two are marked as strong candidates, but the majority have very weak constraints on their spectral energy distributions. Using follow-up observations with SINFONI/VLT, we are able to exclude the most robust candidates as LAEs. We put a strong constraint on the Lyα luminosity function at z ∼ 9 and make realistic predictions for ongoing and future surveys. Our results show that surveys for the highest redshift LAEs are susceptible of multiple contaminations and that spectroscopic follow-up is absolutely necessary.},
  author       = {Matthee, Jorryt J and Sobral, David and Swinbank, A. M. and Smail, Ian and Best, P. N. and Kim, Jae-Woo and Franx, Marijn and Milvang-Jensen, Bo and Fynbo, Johan},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: high-redshift, cosmology: observations, dark ages, reionization, first stars},
  number       = {3},
  pages        = {2375--2387},
  publisher    = {Oxford University Press},
  title        = {{A 10 deg2 Lyman α survey at z=8.8 with spectroscopic follow-up: Strong constraints on the luminosity function and implications for other surveys}},
  doi          = {10.1093/mnras/stu392},
  volume       = {440},
  year         = {2014},
}