adsabs/FOCAL huggingface dataset:
To understand the distribution of Li-rich giants among different stellar components of the Galaxy, we have computed membership probability, based on the recipe given in Reddy, Lambert & Allende Prieto (2006) and references therein, for each of the stars in the selected RGB sample for belonging to one of the three main components of the Galaxy, namely; thin disc, thick disc, and halo. For this, the heliocentric velocities (U, V, W) for each of the sample giant is calculated using the Gaia astrometry (positions, parallax, and proper motions) and radial velocities (RV) from the GALAH DR2. The heliocentric velocities are corrected for the solar motion using Uo = 10, Vo = 5.3, Wo = 7.2 (km s−1) from Dehnen & Binney (1998) to get velocities with respect to the local standard of rest (ULSR, VLSR, WLSR). Entire sample is shown in Toomre Diagram of rotational velocity (VLSR) and sum of quadrature of radial and vertical velocities ([$\rm {\it U}_{\rm LSR}^2 + {\it W}_{\rm LSR}^2]^{1/2}$) (Sandage & Fouts 1987). Li-rich giants are identified by coloured symbols as shown in Fig. 4. We used kinematic boundaries for thin disc ($|V_{\rm Total}|$  = $[U_{\rm LSR}^2 + V_{\rm LSR}^2 + W_{\rm LSR}^2]^{1/2}$ ≤ 80 km s−1), thick disc (80 |VTotal| ≤ 200 km s−1) and halo (|VTotal| > 200 km s−1) which are in accordance with the results in Reddy et al. (2006). Further to quantify the number of giants belonging to different components of the Galaxy, we used probability of 70${{\ \rm per\ cent}}$ or more for any star being considered as a member of particular component. We found 223 Li-rich thin disc stars, which is about 0.8${{\ \rm per\ cent}}$ of total thin disc RGB stars with $P_{\rm thin} \ge 70 {{\ \rm per\,cent}}$ and 69 Li-rich thick disc stars consisting of 0.5${{\ \rm per\ cent}}$ of total thick disc RGB stars with $P_{\rm thick} \ge 70{{\ \rm per\,cent}}$. We have found just three Li-rich giants among 1442 halo giants with $P_{\rm halo} \ge 70{{\ \rm per\,cent}}$. This shows that Li-rich giants are rare ($\lt 1{{\ \rm per\,cent}}$) across stellar components but are relatively more prevalent among metal-rich thin disc component compared to thick disc and very metal poor halo.
Citation: Sandage & Fouts 1987
Citation function: Uses
To this we can add that Zimbardo and coworkers reported in a series of papers that spacecraft observations of SEP intensity-time profiles ahead of interplanetary shocks yielded power laws instead of the exponential profiles predicted by standard DSA. They interpreted this as a sign of superdiffusive spatial SEP transport in the shock vicinity resulting in superdiffusive shock acceleration. They predicted the superdiffusive shock acceleration to be more efficient, producing a harder accelerated power-law spectrum for SEPs, than standard DSA (Zimbardo et al. 2006; Perri & Zimbardo 2007, 2008, 2009; Zimbardo & Perri 2013; Zimbardo et al. 2017, 2020; Zimbardo & Perri 2020). Zimbardo & Perri (2020) explained such superdiffusive transport as a product of subdiffusion in pitch-angle space arising from the observation that Alfvén-wave pitch-angle scattering times in the solar wind have a power-law distribution instead of a single value. Another possibility is that there is a strong presence of SMFRs in the vicinity of heliospheric shocks so that particle trapping effects could result in anomalous diffusive transport and shock acceleration. Evidence is increasing that, in a space plasma with a significant guide/background magnetic field like the solar wind, SMFRs naturally form as part of a self-generated, quasi-two-dimensional (quasi-2D) MHD turbulence component that might dominate other MHD wave turbulence modes. This is supported by observations in the slow solar wind near 1 au (e.g., Matthaeus et al. 1990; Bieber et al. 1996; Greco et al. 2009; Zheng & Hu 2018), MHD simulations (e.g., Shebalin et al. 1983; Dmitruk et al. 2004), and nearly incompressible MHD turbulence transport theory (e.g., Zank & Matthaeus 1992, 1993; Zank et al. 2017, 2018, 2020). It is plausible that SMFRs can have a strong presence ahead of interplanetary shocks. Furthermore, there is evidence that the occurrence of SMFRs peaks at large-scale current sheets in the solar wind where magnetic reconnection produces additional SMFRs that can trap energetic particles (Khabarova et al. 2015, 2016; Hu et al. 2018). Many of these current sheets occur behind traveling shocks (Khabarova & Zank 2017). Recently, a theoretical investigation was launched to determine the transmission of quasi-2D SMFRs through a perpendicular shock (Zank et al. 2021). The results show a strong enhancement in the magnetic energy density of the SMFR magnetic island component behind the shock, thus confirming a strong presence of SMFRs downstream of the shock as well.
Citation: Zimbardo et al. 2017
Citation function: Compare/Contrast
One of the first models of MRI-driven accretion in protoplanetary discs was constructed by Gammie (1996), who proposed that Ohmic resistivity (due to weak coupling of charged species to the magnetic field) quenches the MRI in a ‘dead’ mid-plane region surrounded by ‘active layers’, which are ionized by cosmic rays. This layered-accretion scenario has been refined as additional non-thermal ionization sources (X-rays, UV radiation) and non-ideal magnetohydrodynamic (MHD) effects (ambipolar diffusion and the Hall effect) have been included (e.g. Igea & Glassgold 1999; Sano et al. 2000; Fromang, Terquem & Balbus 2002; Salmeron & Wardle 2003, 2005, 2008; Ilgner & Nelson 2006; Bai & Goodman 2009; Bai & Stone 2011; Wardle & Salmeron 2012). Several theoretical studies, spanning both analytical (e.g. Blaes & Balbus 1994; Desch 2004; Kunz & Balbus 2004) and numerical work (e.g. Hawley & Stone 1998; Bai & Stone 2011, 2013b; Simon et al. 2013a,b), have shown that ambipolar diffusion plays a major role in determining the level of turbulence in protoplanetary discs. In the outer regions (radii R ≳ 30 au), ambipolar diffusion acts to reduce the strength of MRI-driven turbulence close to the disc mid-plane; turbulence is stronger above this ‘ambipolar damping zone’ in a thin layer of gas strongly ionized by FUV photons (Perez-Becker & Chiang 2011; Simon et al. 2013a,b). To produce accretion rates consistent with observations, a large-scale magnetic field threading the disc perpendicular to the disc plane is required (Simon et al. 2013a,b). This net field enhances turbulence, despite the damping effect of ambipolar diffusion, and allows additional angular-momentum loss via a magnetic wind (akin to the Blandford & Payne 1982 mechanism). In the inner disc, both local (Bai & Stone 2013b) and global (Gressel et al. 2015) simulations have shown that ambipolar diffusion can quench the MRI in the purported active layers of Gammie's (1996) model. In those cases, a large-scale magnetic field is again necessary to drive accretion at the observationally inferred rates, this time solely via a magnetic wind in a manner akin to previous models of wind-driven accretion in protoplanetary discs (e.g. Wardle & Koenigl 1993; Shu et al. 1994; Salmeron, Königl & Wardle 2007).
Citation: Salmeron & Wardle; 2005
Citation function: Background
PNs are expanding shells of the luminous gas expelled by dying stars of low and intermediate masses (LIMS). They stem from objects that have lifetimes up to gigayears. The ionized gas surrounding the central star shows emission lines of highly ionized species from which the abundances can be derived. The neon abundance can be compared and related to the results from stellar abundance analysis, as neon (and oxygen) originates from primary nucleosynthesis in massive stars (≥10 M⊙) and is therefore nearly independent of the evolution of LIMS, the progenitor stars of PNs (Henry 1989; Henry et al. 2004). For comparison, we collected several studies, where the neon abundances were obtained in PNs. We would not say that the abundances from PNs are very accurate, because the differences between abundances from collisionally excited lines and optical recombination lines can be much higher in PNs compared to those of H ii regions. For example, according to Wang & Liu (2007), in four Galactic disk PNs (He 2–118, H 1-35, NGC 6567, and M1-61), the mean neon abundance calculated from collisionally excited lines is 7.78 ± 0.23, while it is 8.72 ± 0.60 from optical recombination lines. Figure 9 presents neon abundances from different sources, including five studies focused on PNs. In those studies, where it was mentioned, we adopted neon abundances obtained from collisionally excited lines, e.g., Tsamis et al. (2003) and Wang & Liu (2007). The mean value of log ϵNe = 7.84 ± 0.24 was calculated on the basis of neon abundances in six Galactic disk PNs (Wang & Liu 2007). The mean value of the neon abundance log ϵNe = 7.99 ± 0.22 dex was calculated from six PNs (Hu 1-2, IC 418, NGC 40, NGC 2440, NGC 6543, NGC 7662) with Galactocentric distances from 7.9 kpc to 8.9 kpc from the summary of Pottasch & Bernard-Salas (2006). The value of log ϵNe = 7.76 ± 0.24 dex was derived from 16 Galactic PNs located at Galactocentric distances from 8.0 to 8.9 kpc in Stanghellini et al. (2006). The log ϵNe = 8.02 ± 0.25 dex was obtained from Marigo et al. (2003) from three PNs (NGC 6543, NGC 7027, NGC 7662), which are located at distances no more than 1.0 kpc. We adopted the mean value log ϵNe = 8.15 ± 0.21 dex, which was calculated from 16 Galactic PNs from Tsamis et al. (2003).
Citation: Henry 1989
Citation function: Background
Both SHINE and GPIES surveys recently discovered three new exoplanets (Macintosh et al. 2015; Chauvin et al. 2017b; Keppler et al. 2018) and a few additional higher-mass brown dwarfs (Konopacky et al. 2016; Cheetham et al. 2018). Smaller surveys using SPHERE and GPI also discovered several substellar companions (Milli et al. 2017a; Wagner et al. 2020; Bohn et al. 2020). These surveys offer unprecedented detection, astrometric, and spectrophotometric capabilities that allow us to characterize fainter and closer giant planets, such as the recent discovery of 51 Eri b (2 MJup at 14 au, T5-type, of an age of 20 Myr; Macintosh et al. 2015; Samland et al. 2017), HIP 65426 b, a young, warm, and dusty L5-L7 massive Jovian planet located at about 92 au from its host star (Chauvin et al. 2017b), and the young solar analogue PDS 70, which is now known to actually host two planets PDS 70 b discovered during the SHINE campaign (Keppler et al. 2018; Müller et al. 2018) and PDS 70 c by MUSE (Haffert et al. 2020). Such surveys also provide key spectral and orbital characterisation data for known exoplanets (e.g., De Rosa et al. 2016; Samland et al. 2017; Chauvin et al. 2018; Wang et al. 2018; Cheetham et al. 2019; Lagrange et al. 2019; Maire et al. 2019). Despite these new discoveries, SHINE and GPIES have yielded significantly fewer exoplanet detections than predicted, with their use of extrapolations of radial velocity planet populations to larger semi-major axes (e.g., Cumming et al. 2008). This results in our setting strong statistical constraints on the distribution of giant exoplanets at separations of >10 au from their stars, as well as sub-stellar companions to young stars (Nielsen et al. 2019; Vigan et al. 2021). As these systems are young (100 Myr), and thus closer to their epoch of formation than, for instance, radial-velocity planets (typically 1–10 Gyr), statistical analyses of large direct-imaging surveys can provide hints for the potential formation mechanism responsible for producing giant exoplanets on wide orbits.
Citation: Samland et al. 2017; Samland et al. 2017
Citation function: Background; Background
Both Nel (2016) and Zhao et al. (2018) report that these parallel mean free paths are smaller during periods of high solar activity and larger during solar minima, with the opposite being true for the resulting perpendicular mean free paths. Zhao et al. (2018) also show that such solar cycle dependences would not be fully accounted for if only the solar cycle changes in the HMF were taken into consideration. These mean free paths also display complicated spatial dependences if turbulence quantities beyond 1 au, yielded by various turbulence transport models (see, e.g., Oughton et al. 2011; Usmanov et al. 2016; Wiengarten et al. 2016; Zank et al. 2017), taking into account observed latitudinal variations of turbulence quantities in the heliosphere (Forsyth et al. 1996; Bavassono et al. 2000a, 2000b; Erdös & Balogh 2005), were used as inputs for the turbulence quantities (e.g., Engelbrecht & Burger 2013a, 2015b; Chhiber et al. 2017; Moloto et al. 2018). Furthermore, mean free paths such as those discussed have, when used in conjunction with turbulence-reduced drift coefficients (see, e.g., Minnie et al. 2007b; Engelbrecht et al. 2017) in 3D stochastic modulation codes, led to computed galactic intensities in reasonable agreement with spacecraft observations at Earth (see, e.g., Engelbrecht & Burger 2013a, 2013b; Qin & Shen 2017) and even for several different solar minima (Moloto et al. 2018). The necessity of taking cosmic-ray drift effects into account, combined with the complicated spatial dependences and the fact that none of the diffusion coefficients described above display a P1 rigidity dependence, implies that a convection–diffusion or force-field approach would not be ideal to describe long-term modulation, and that the assumptions implicit to the effective diffusion coefficient used in these formulations are unrealistic. This latter point would call into question any conclusions drawn as to historic solar parameters from quantities such as the modulation potential.
Citation: Engelbrecht & Burger 2013a
Citation function: Background; Similarities
Additional information can be derived from the abundance ratios measured in the ICM. For example, the Mn/Fe and Ni/Fe ratios are both sensitive to the electron capture rates during SNIa explosions, and are therefore crucial indicators of their progenitor channels (Seitenzahl et al. 2013a; Mernier et al. 2016a; Hitomi Collaboration 2017), while ratios of lighter elements can in principle provide constraints on the IMF and the initial metallicity of the SNcc progenitors (e.g. de Plaa et al. 2007; Mernier et al. 2016a). By pushing current observatories to their limit, recent studies derived constraints on the relative fraction of SN events that effectively contribute to the ICM enrichment. These measurements showed that SNIa and SNcc contribute relatively equally to the overall chemical enrichment in the ICM (Werner et al. 2006; de Plaa et al. 2006, 2017; Bulbul et al. 2012; Mernier et al. 2016a). The comprehensive study of Simionescu et al. (2019) compiled the most accurate abundance measurements of the Perseus cluster (taken with the XMM-Newton RGS and Hitomi SXS instruments) and compared them to state-of-the-art SNIa and SNcc yield models. Their surprising conclusion is that no current set of models is able to reproduce all the observed abundance ratios at once. In particular, the measured Si/Ar ratio tends to be systematically overpredicted by models, even when taking calibration and atomic uncertainties into account. Whereas further improvement of stellar nucleosynthesis models is expected, the non-negligible systematic errors associated to these observations and the lack of highly sensitive, spatially resolved high-resolution spectroscopy prevents us from steering any considerable change in the paradigm (see also de Grandi & Molendi 2009). In fact, measurements from currently flying missions are performed with moderate collective area, either over the whole X-ray band (0.4–10 keV) with modest spectral resolution (> 100 eV), or with higher resolution dispersive spectroscopy but over the low E band (0.3–2 keV) and without any spatial resolution, which considerably limits interpretations.
Citation: Werner et al. 2006
Citation function: Compare/Contrast
In recent years, several large-scale pulsar surveys have been undertaken to search for new pulsars (Cordes et al. 2006; Keith et al. 2010; Barr et al. 2013; Boyles et al. 2013; Deneva et al. 2013; Coenen et al. 2014; Stovall et al. 2014). One of the drivers for such surveys is the discovery of millisecond pulsars (MSPs). MSPs are formed through accretion from a companion during an X-ray binary phase (Alpar et al. 1982; Bhattacharya & van den Heuvel 1991) in which the pulsar is “recycled.” This accretion phase spins the pulsar up to very fast rotational rates (spin periods 





 ms). Such pulsars are useful for a variety of physical applications. Examples include tests of theories of gravity using MSP–white dwarf systems such as PSR J1738+0333 and PSR J0348+0432 (Freire et al. 2012; Antoniadis et al. 2013) and triple systems like PSR J0337+1715 (Ransom et al. 2014); tests of general relativity using double neutron star systems, such as J0737−3039 (Kramer et al. 2006) and PSR B1913+16 (Weisberg et al. 2010); the study of binary systems such as eccentric MSPs like PSRs J1903+0327 (Champion et al. 2008) and J1950+2414 (Knispel et al. 2015) which are interesting due to their peculiar binary evolution; and constraining the equation of state of dense matter using measurements of neutron star masses (Demorest et al. 2010; Antoniadis et al. 2013). Another major driver for the discovery of new MSPs is the effort to detect gravitational wave emission using an array of pulsars (NANOGrav Collaboration et al. 2015; Lentati et al. 2015; Reardon et al. 2016). The large-scale pulsar surveys mentioned above, combined with targeted searches of unidentified gamma-ray sources from the Fermi Gamma-Ray Space Telescope (e.g., Hessels et al. 2011; Keith et al. 2011; Ransom et al. 2011; Kerr et al. 2012), have resulted in the discovery of about 90 new MSPs in the past 5 years, an increase of 40% in the known Galactic MSP population. A subset of the newly discovered sources are eclipsing systems that appear to fall into two categories (e.g., Freire 2005; Roberts 2012). The first category, known as black widow systems, has very low mass, degenerate companions (





) believed to be the result of ablation by the pulsar. The second, known as redback systems, has low to moderate mass, non-degenerate companions (





).
Citation: Champion et al. 2008
Citation function: Motivation; Motivation
If we recall the tight, monotonic dependence of the position of galaxies along the SF sequence in the diagram with metallicity (as outlined in Section 3.1), we can interpret our global results of Figs 4 and 5 as a manifestation of the existence of an O/H versus N/O relation for SDSS star-forming galaxies, whose intrinsic scatter is reflected and, to some extent, translated into the observed distribution of emission line ratios within the [N ii]-BPT. A tight relationship between O/H and N/O abundances is indeed observed in both H ii regions and local galaxies, especially at M⋆ ≳ 109.5M⊙ (Vila Costas & Edmunds 1993; van Zee et al. 1998; Pérez-Montero & Contini 2009; Pilyugin et al. 2012; Andrews & Martini 2013; Hayden-Pawson et al. 2021), and it is set by the predominant nucleosynthetic origin of nitrogen from CNO burning of pre-existing stellar carbon and oxygen in low- and intermediate-mass stars experiencing the AGB phase (i.e. the ‘secondary’ nitrogen production mechanism, Kobayashi, Karakas & Umeda 2011; Ventura et al. 2013; Vincenzo et al. 2016); alternatively, Vincenzo & Kobayashi (2018) reproduced the observed N/O-O/H relation introducing failed supernovae (SNe) in massive stars within their cosmological simulations. Recently, such relationship between O/H and N/O has been suggested as even tighter than the one between M⋆ and N/O (Hayden-Pawson et al. 2021), in contrast to what claimed by previous studies (e.g. Andrews & Martini 2013; Masters et al. 2016). In light of our results, this would confirm that deviations in N/O at fixed O/H are more likely to be related to the offset from the SF sequence in the [N ii]-BPT than relative variations in M⋆, although the two are clearly physically correlated. The connection between the two diagrams is also readily evident if we look at the distribution of our galaxy sample in the N/O versus O/H diagram, as shown in Fig. 8 (where [N ii] λ6584/[O ii] λ3727, 29 is converted to N/O following the Te-based calibrations presented in Hayden-Pawson et al. 2021); here, each hexagonal bin is colour-coded by the average distance D of galaxies from the best-fitting line of the [N ii]-BPT, almost perfectly tracing the scatter around the median N/O versus O/H relation.
Citation: Pérez-Montero & Contini 2009
Citation function: Similarities
Citation: Ventura et al. 2013
Citation function: Uses; Uses
We now consider upcoming spectroscopic surveys. We consider two cases for the CMB lensing map, including (1) the full Planck CMB lensing map and (2) the Advanced ACTPol5 CMB lensing map. In both cases, we assume that the CMB lensing maps will be estimated using the temperature map and both E and B polarization maps, and we assume the B map only contains noise. We predict the noise in the Planck lensing map assuming the detector sensitivity and beam sizes listed in the Planck Bluebook (Planck Collaboration 2006). Advanced ACTPol will survey 20 000 deg2, and its increased temperature and polarization sensitivity will create a CMB lensing map that is an order of magnitude more sensitive than Planck. The specifications we use for Advanced ACTPol are listed in Table 3. For spectroscopic surveys, we consider the DESI emission line galaxy (ELG), LRG, and quasar surveys, as well as the Euclid Hα survey and the WFIRST Hα and O iii combined survey. The properties of the surveys are listed in Table 1. For DESI, we assume the same values as in the DESI Conceptual Design Report:6 bLRGD(z) = 1.7, bELGD(z) = 0.84, bQSOD(z) = 1.2, where D(z) is the growth factor. We also assume a 4 per cent error in β within Δz = 0.1 bins. Note that Advanced ACTPol's survey area overlaps with only ∼75 per cent of DESI's area; we take this into account in our DESI forecasts. For Euclid and WFIRST ELGs, we assume b(z) = 0.9 + 0.4z, a fit (Takada et al. 2014) to semi-analytic models (Orsi et al. 2010) that compares well with data. We determine the redshift distribution of Euclid Hα galaxies using the Hα luminosity function from Colbert et al. (2013) and assume a flux limit of 4× 10−16. This flux limit is in the middle of the range being considered, so the following Euclid forecasts can change accordingly. We also assume a 3 per cent error in β within Δz = 0.1 bins for Euclid and WFIRST (Amendola et al. 2013). For all subsequent forecasts, we assume EG measurements over angular scales 100 ≤ ℓ ≤ 500.
Citation: Planck Collaboration 2006
Citation function: Uses