adsabs/FOCAL huggingface dataset:
However, the sensitivity limits of most current submillimeter surveys only allow for the study of the most extremely star-bursting systems (e.g., Asboth et al. 2016; Geach et al. 2017; Simpson et al. 2019), which may represent merely a tip of an iceberg of dust-obscured star formation in the early Universe. A potential population of more typical dusty star-forming galaxies at high-z is still to be found (Wang et al. 2017). The Atacama Large Millimetre/submillimetre Array (ALMA) has now opened a new avenue to refine our understanding of dusty galaxies at high redshifts, enabling to uncover faint SMGs down to a flux level of 0.1–1 mJy. Several ALMA blind surveys have been performed and allowed to detect and characterize the faint SMGs across cosmic times (e.g., Aravena et al. 2016; Wang et al. 2016b; Dunlop et al. 2017; Umehata et al. 2017; Franco et al. 2018; Williams et al. 2019; Yamaguchi et al. 2019; González-López et al. 2020). Based on the ALMA survey of GOODS-South field over an area of 69 arcmin2, Franco et al. (2018) found that 20% of the 1.1 mm sources are not detected with HST down to a depth of H ∼ 28 mag, and suggested that they are massive main-sequence star-forming galaxies at z > 4 (see also, Yamaguchi et al. 2019; Umehata et al. 2020). A similar fraction of HST-dark galaxies has also been found in the ALMA [C ii] survey of main-sequence galaxies at 4.4  z  5.9 (∼14%, Gruppioni et al. 2020). Conversely, the existence of such HST-dark galaxies can also be uncovered by focusing the reddest galaxies in the IRAC and H bands (H-[4.5 μm] > 4.0), namely H-dropouts (Huang et al. 2011; Caputi et al. 2012; Wang et al. 2016a). Follow-up continuum observations with ALMA of a sample of 63 H-dropouts have yielded detections of 39 sources down to an 870 μm flux density of 0.6 mJy (Wang et al. 2019). They further suggested that the ALMA-detected H-dropouts are the bulk populations of massive (M
⋆ ≳ 1010.3
M
⊙) star-forming galaxies at z > 3 with the contribution to star formation rate density an order of magnitude higher than that of equivalently massive LBGs. To uncover the nature of H-dropouts and the critical role they play in the cosmic evolution of massive star-forming galaxies, we need to explore the fainter population that might have even fainter (sub)millimeter fluxes.
Citation: Umehata et al. 2017
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Interestingly, from ∼11:33:40 UT, the PAD of the suprathermal electrons changes to cigar type, in association with a dramatic drop of electron flux (Figure 2(a)). This change of electron PAD and flux is related to a magnetic dip structure that is manifested by a conspicuous decrease of the magnetic field strength (Figure 2(b)). In contrast to the magnetic field enhancement observed at ∼11:33:08 UT, the magnetic dip structure should arise from the local expansion of flux tubes, which are driven by the two opposite flows (see the shaded region in Figure 2(c)). The observed electron cigar distribution and the associated magnetic dip are a strong indication of the betatron cooling effect. This betatron-mediated cigar distribution has been suggested in previous studies (Fu et al. 2011b, 2012c, 2013b; Liu et al. 2017c) but never clearly observed. These observations, for the first time, show a direct link between the cigar distribution and betatron cooling. Note that in the trailing edge of the magnetic dip region, a magnetic hump structure, indicated by the sharp enhancement of magnetic field, is observed at ∼11:33:55 UT (Figure 2(b)). This magnetic hump, reminiscent of the Earthward-propagating dipolarization-front structure typically generated by magnetic reconnection in the midtail (Fu et al. 2012d, 2012e, 2013a, 2015, 2016, 2017; Liu et al. 2013, 2018a, 2018b, 2018c; Cao et al. 2017; Peng et al. 2017; Yao et al. 2017; Chen et al. 2018), was possibly formed due to the local contraction of flux tubes driven by the ion flow with an increasing velocity in the Earthward direction (Figure 2(c)). Associated with this magnetic hump, a very weak pancake distribution of suprathermal electrons is observed (Figure 2(a)), and strong waves near the electron gyrofrequency are also observed (Figures 2(e) and (f)). These waves are whistler-mode; they indicate that the betatron acceleration inside the magnetic hump was accompanied by non-adiabatic effects (Fu et al. 2009, 2010a, 2010b, 2012a, 2012b) and is still ongoing (Fu et al. 2011a; Khotyaintsev et al. 2011; Wang et al. 2017; Yang et al. 2017).
Citation: Fu et al.; 2012c
Citation function: Similarities; Similarities
Relatively few such global convective dynamo studies have been conducted in the domain of M-dwarf stars. Early work by Browning (2008) considering lower mass FC M dwarfs found that the deep CZ could support very strong nonaxisymmetric fields, which strongly quenched the star’s differential rotation. Later, more turbulent simulations of FC M-dwarf stars led to a number of interesting results. Yadav et al. (2015a) found strong, axisymmetric fields which were statistically steady in time and recovered many of the observed characteristics of M-dwarf surface fields. A somewhat slower rotating model (Yadav et al. 2015b) revealed that flux concentration by merging downflow lanes could lead to the formation of large, persistent high-latitude starspots in these stars. A still slower rotating model (Yadav et al. 2016) built large-scale, axisymmetric, cycling magnetic fields of somewhat lower amplitude which did not eliminate the star’s differential rotation, reminiscent of the distributed αΩ-type dynamos prevalent in solar-like contexts. Brown et al. (2020) presented the first simulation of a stratified, rotating FC star whose computational domain extended to r = 0, finding a preference for hemispheric dynamo states. Similar models were recently explored by Käpylä (2021) for a broad range of rotation rates, which yielded a variety of results. At slow rotation, differential rotation was antisolar, and dynamo action dipole dominant. Moderate rotation rates yielded solar-like profiles, which were then magnetically quenched in the fastest rotators, yielding nonaxisymmetric dynamos. In Bice & Toomre (2020; hereafter BT20), we presented an exploration of the influence exerted by a tachocline in more massive, shell-convecting M-dwarf stars as a contributing factor to the break in observed magnetic activity across the tachocline divide. Our models produced a wide variety of field configurations, nearly all of which led to quenching of the differential rotation to a significant degree. We found that including a tachocline in models of early M-dwarf stars led to their surface fields being more favorable for rapid stellar spin-down, which may contribute to the formation of the tachocline divide.
Citation: Yadav et al. 2016
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At quasi-perpendicular shocks, the average shock structure is dominated by a foot of reflected ions, which is upstream of the shock ramp where the major thermalization and deceleration occurs. Non-stationarity in the form of rippling of the surface or steepened whistler waves (Moullard et al. 2006; Lobzin et al. 2007) is an intrinsic feature of the shock, but this is generally manifest as minor perturbations on top of an otherwise stationary shock ramp. Simulations have predicted that if the fraction of ions reflected by the shock front becomes sufficiently high, the quasi-perpendicular shock can become periodically reforming on timescales of the ion gyroperiod. Various theories have been suggested for such non-stationarity, including self-reformation where a new shock ramp grows at the edge of the foot (Biskamp & Welter 1972a; Lembège & Dawson 1987), whistler-induced reformation (Biskamp & Welter 1972b; Scholer & Burgess 2007), kinetic instabilities such as the Buneman and modified two-stream instability (e.g., Cargill & Papadopoulos 1988; Matsukiyo & Scholer 2003, 2006b; Scholer et al. 2003; Scholer & Burgess 2007; Matsumoto et al. 2013), and gradient catastrophe of nonlinear whistler waves due to steepening (Krasnoselskikh et al. 2002). However, it has not been until recently that such non-stationarity has been confirmed with in situ spacecraft observations. In a survey of Cassini shock crossings at Saturn, Sulaiman et al. (2015) found evidence of a periodically reforming shock, pulsating at a period near 0.3 of the ion gyroperiod in the unperturbed upstream medium. This period agrees with the time taken for a specularly reflected proton to gyrate across the foot and return to the main shock ramp. Sulaiman et al. (2015) also report that these periodic non-stationary shocks are primarily found in the very high Mach number regime, which gives evidence for a relation between Mach number and reformation. The main processes behind the non-stationary behavior of these very high Mach number shocks, such as the details of the ion- and electron-scale processes acting within the shock transition, remain elusive.
Citation: Scholer & Burgess 2007
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There are some indications that available models of the post-AGB and CSPN phases are not accurate enough. First, the two available grids of post-AGB models (Vassiliadis & Wood 1994; Blöcker 1995a) do not agree with each other on the predicted timescales (Zijlstra et al. 2008). Second, consistency between the masses of white dwarfs and those of CSPNe seems to require faster evolutionary speeds than predicted by both sets of models (Gesicki et al. 2014). Third, present models of the CSPNe phase are unable to explain why the cut-off of the PNe luminosity function is constant in most galaxies (Marigo et al. 2001, 2004). Lastly, post-AGB stellar evolution models, computed with updated physics in a reduced mass range (Kitsikis 2008; Weiss & Ferguson 2009), show a strong disagreement with the previous grids. This is not a surprise since many improvements have been carried out in the field of stellar physics in recent decades. Most importantly, available grids have been computed with opacities, which are now 45 years old (Cox & Stewart 1970b,a) before the big changes introduced by the OPAL (Iglesias & Rogers 1996), and Opacity Project (Seaton 2007) redeterminations. Similarly, nuclear reaction rates, equation of states, conductive opacities, and neutrino emission rates adopted in the models date from the early eighties and even earlier. In addition, Herwig et al. (1997) showed that the existence of carbon stars at low luminosities can be explained by the addition of mixing beyond the formal convective boundaries during the thermal pulses (TP) on the AGB. Finally, Marigo (2002) showed that C-rich molecular opacities are essential to predict the correct effective temperatures once the AGB models become carbon rich (NC/NO> 1, by number fractions). This is particularly important because of the impact of effective temperatures on the mass loss rates. While all these improvements in stellar modeling have been implemented in AGB stellar models, and very detailed and exhaustive grids and models are available (Weiss & Ferguson 2009; Cristallo et al. 2009, 2011; Ventura & Marigo 2010; Karakas 2010; Lugaro et al. 2012; Constantino et al. 2014; Doherty et al. 2015), the inclusion of these improvements in post-AGB stellar models is still missing. It is time for a recomputation of the post-AGB models in the light of all these advances.
Citation: Weiss & Ferguson 2009
Citation function: Differences; Differences
In this paper, we consider resonance scattering on a two-level atom with an infinitely sharp and unpolarized lower level. As for the frequency redistribution, we consider both CRD and angle-averaged PRD. In an unmagnetized one-dimensional spherically symmetric atmosphere, the polarized radiation field is axially symmetric and is described by 





. We also take into account the effects of radial velocity fields. We solve the concerned transfer equation in the CMF and in the nonrelativistic regime of velocity fields. To efficiently handle the sphericity effects, we solve the spherical transfer equation in the (p, z) coordinate system (Hummer & Rybicki 1971), which is also called the tangent-ray method. Here z is the distance along the tangent rays and p is impact parameter (see Figure 1 in Megha et al. 2019). Following Frisch (2007), we express the Stokes vector components in terms of their irreducible components. From here on we present all the basic equations in the irreducible basis (see Sampoorna & Trujillo Bueno 2010 for details). The CMF polarized PRD transfer equation for a spherically symmetric medium in (p, z) representation under the nonrelativistic limit is given by (see also Equation (17) of Megha et al. 2019)
1





where x denotes the nondimensional frequency and 





 denotes the irreducible Stokes vector with “+” and “−” referring to the outgoing and incoming rays, respectively. The radial optical depth is defined as dτr = −χl(r)dr, where r is the radial distance and χl(r) is the line averaged absorption coefficient. In the CMF the monochromatic optical depth along the tangent ray is given by dτ = [φ(x) + βc]dτr/μ, where φ(x) is the line absorption profile function and βc = χc(r)/χl(r) with χc(r) denoting the continuum absorption coefficient. The direction cosine of the tangent ray about the radius vector of the intercepting radial shell is given by 





. In Equation (1), 





 denotes the CMF term, which has the form
2





where χ(r, x) = χl(r)φ(x) + χc(r), and
3





The symbol V denotes the ratio of radial (vr) to the thermal (





) velocities. In Equation (1), 





 represents the irreducible CMF total source vector and is given by
4





where the line source vector is of the form
5





Here ϵ gives the probability of destruction of photons by inelastic collisions, Bν0 is the Planck function at the line center frequency ν0, and 





. The continuum is assumed to be unpolarized. Therefore, the continuum source vector is given by 





. The frequency-averaged PRD mean intensity vector is given by
6





where 





 is the 2 × 2 nonmagnetic angle-averaged PRD matrix (Domke & Hubeny 1988; Bommier 1997), and
7





The Rayleigh phase matrix 





 in the irreducible basis is given in Appendix A of Frisch (2007). It is useful to rewrite Equation (7) as
8





where
9
Citation: Sampoorna & Trujillo Bueno 2010
Citation function: Uses; Uses
In this work, we focus on the 56 most massive (M* ≥ 1011 M⊙) galaxies at 1.4 ≤ z ≤ 2, 31 of which have spectroscopic redshifts. Two more objects entered the original sample, but they have been excluded from this study, because their WFC3/HST images are not available, or too noisy to perform SB fitting, due to the proximity of saturated stars. The sample was culled from the K-selected (K(Vega)  22) multiband catalogue of Daddi et al. (2007a, hereafter D07), including data from all the available filters in GOODS-S, i.e. HST/ACS optical, F435W (B), F606W (V), F775W (I), and F850LP(z), VLT/ISAAC near-IR, J, H, K, and Spitzer/Infrared Array Camera (IRAC), 3.6, 4.5, 5.8, and 8.0 μm (for more details on the data sets see Giavalisco et al. 2004). The optical/near-IR photometry was then complemented with the 24 μm catalog (Daddi et al., in preparation), built as summarized in Section 2.1 from the Multi-Band Imaging Photometer for Spitzer (MIPS) images (Rieke et al. 2004). Far-IR fluxes were extracted (Daddi et al., in preparation) from the publicly released PACS 70–160 μm data from Herschel GOODS (Elbaz et al. 2011), and SPIRE 250 μm data from Herschel Multi-tiered Extragalactic Survey (HerMES; Oliver et al. 2010). For objects without spectroscopic information, we used photometric redshifts from the public GOODS-MUSIC catalogue, which agree well with the spectroscopic ones (Δz/(1 + z) ≃ 0.03) for galaxies at z  2 (cf. Grazian et al. 2006, 2007). Although the uncertainties on photometric redshifts could result in the inclusion in the sample of a few lower redshift contaminants, we avoided applying colour criteria to pre-select high-z objects, in favour of completeness. The HST/WFC3/F160W H-band image mosaic (>5σ point source sensitivity for H160  27.7, AB system) drizzled to a pixel scale of 0.06 arcsec, was exploited to study galaxy morphology in the optical rest frame with a very high resolution (FWHM ∼ 0.18 arcsec ≃ 1.5 kpc). For more details on the observations and data reduction see Grogin et al. (2011) and Koekemoer et al. (2011).
Citation: Rieke et al. 2004
Citation function: Uses; Uses
Having a line list that is as complete as possible is crucial for doing proper radiative transfer computations in high temperature atmospheric environments. However, computing the line opacities for a large number of lines can be computationally challenging. For example, the ExoMol line list of CH4 contains on the order of 1010 lines (Yurchenko & Tennyson 2014). Computing the exact pressure and temperature broadened Voigt profile for each of these lines is computationally extremely demanding. There are several approximate methods for computing Voigt profiles available in the literature (e.g. Humlícek 1982; Weideman 1994; Zaghloul & Ali 2012). Also, much effort is spend succesfully on making these approximate methods faster and more accurate (see e.g. Poppe & Wijers 1990; Letchworth & Benner 2007). These methods all focus on obtaining a given accuracy of the exact shape of the Voigt profile by applying mathematical approximations to decrease the computation time. While these methods still require significant computation time, they are now routinely applied to compute Voigt profiles in many applications. The fastest code able to compute Voigt profiles of large numbers of lines at this moment is the HELIOS-k code (Grimm & Heng 2015). This code is able to compute ~ 105 lines per second on a dedicated NVIDIA K20 GPU based machine. This implies that the computation of 1010 lines still requires on the order of one day for a single point in pressure temperature space. Usually a grid of pressure and temperature points is required. Thus, there is the need for an even faster method. In addition, we have to make sure that there are no systematic errors in the computations because a small systematic error in a single line can become large when computed for 1010 lines. Thus, we seek a method that is statistically exact, preserves the integrated opacities and the average shape of the lines, and computes the line profile accurately for the stronger lines.
Citation: Weideman 1994
Citation function: Background
Modern optical imaging surveys measure the positions and ellipticities of millions of galaxies; from them, the galaxy overdensity field as well as the gravitational lensing shear field can be derived. The two-point auto and cross-correlations of these two fields are the two-point correlation functions of cosmic shear, galaxy–galaxy lensing and galaxy clustering. A joint analysis of these correlation functions can break degeneracies between cosmological and nuisance parameters, leading to tighter cosmological constraints (Joachimi & Bridle 2010). Several earlier studies have indeed considered such joint analyses (Cacciato et al. 2013; Mandelbaum et al. 2013; More et al. 2015; Kwan et al. 2017; Nicola, Refregier & Amara 2017), albeit very few in a modified gravity context. Among the latter, Joudaki et al. (2018) recently performed a combined analysis of cosmic shear tomography, galaxy–galaxy lensing tomography, and redshift space multipole power spectra using data from KiDS-450 (∼450 deg2 of cosmic shear data from the KiDS survey) and two overlapping spectroscopic surveys, the 2-degree Field Lensing Survey4 (2dFLenS; Blake et al. 2016) and the Baryon Oscillation Spectroscopic Survey5 (BOSS; Dawson et al. 2013). They found that none of the extended cosmologies considered were simultaneously favoured in a model selection sense and able to resolve the discordance with Planck, except for an evolving dark energy component with a time-dependent w0 − wa equation of state. Amon et al. (2018) presented a measurement of EG, a statistic combining measurements of weak gravitational lensing, galaxy clustering, and redshift space distortions, proposed as a consistency test of General Relativity (Zhang et al. 2007). They determined the value of EG using data from the KiDS, 2dFLenS, BOSS, and Galaxy And Mass Assembly6 (GAMA; Driver et al. 2009, 2011; Liske et al. 2015) surveys; their results show that measurements of the EG statistic cannot be conducted as consistency checks of General Relativity until the aforementioned tension in cosmological parameters is resolved, and their EG measurements favour a lower matter density cosmology than the CMB. Recently, DES Collaboration (2019) presented a combined analysis of galaxy clustering and weak gravitational lensing from the first-year data of the Dark Energy Survey, targeting modifications of the metric potentials that would be a signal of modified gravity. They found that their constraints are compatible with a cosmological constant scenario.
Citation: Blake et al. 2016
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Sunspot light bridges can be formed by the fragmentation of the umbra in the decay phase or during the merging of different magnetized areas during the formation of the sunspot in complex active regions (Bray & Loughhead 1964; Garcia de La Rosa 1987). At the last stages of a sunspot, the photospheric-like conditions are recovered as a consequence of the splitting of the umbra, and a granulation pattern similar to that of the quiet Sun is found in light bridges (Vazquez 1973), although the light-bridge convection cells differ significantly from normal granules (Lagg et al. 2014). Understanding the decay of sunspots requires the study of the magnetic and dynamical structure of light bridges. Previous studies have classified light bridges based on their morphological properties. Light bridges separating two umbral regions are called strong light bridges (e.g., Sobotka et al. 1993, 1994; Jurčák et al. 2006; Rimmele 2008). Their brightness is similar to that of the penumbra, and they typically appear between two regions with the same polarity. Faint light bridges (e.g., Lites et al. 1991; Sobotka et al. 1993) are elongated bright structures that penetrate the umbra. They are composed of rows of bright grains with sizes comparable to umbral dots. Light bridges can exhibit different internal structures. Most of them show several segments along their length that resemble granules (Berger & Berdyugina 2003), while some light bridges are similar to the bright filaments seen in the penumbra (Lites et al. 2004). All types show a weakened magnetic field strength relative to the surrounding umbra and more strongly inclined field lines (e.g. Beckers & Schröter 1969; Lites et al. 1991; Leka 1997), which in some case even exhibit a polarity reversal (Lagg et al. 2014). Observations are consistent with a reduced field strength in the photosphere, with a magnetic canopy extending from either side of the light bridge and merging at the top (Jurčák et al. 2006; Lagg et al. 2014). The velocity field measured in light bridges shows evidence of their convective origin (Rimmele 1997; Hirzberger et al. 2002; Lagg et al. 2014). Recently, Schlichenmaier et al. (2016) have also found evidence that the umbral magnetic field is wrapped around light bridges. The authors defined a new type, the plateau light bridge, with Y-shaped dark canals that resemble penumbral grains and suggest the presence of inclined magnetic fields. Several dynamic phenomena have been detected at the chromosphere above light bridges, including recurrent plasma ejections visible in Hα (Roy 1973; Asai et al. 2001), Ca ii  H (Shimizu et al. 2009), and other bands (AIA 1600 and 1700 Å, IRIS 1330 and 1400 Å, Toriumi et al. 2015), brightness enhancements in the TRACE 1600 Å band (Berger & Berdyugina 2003), or fan-shaped jets observed in Hα (Robustini et al. 2016). All these processes are considered to be caused by the interaction of the light bridge magnetic field with the surrounding atmosphere through magnetic reconnection events.
Citation: Sobotka et al. 1993; Sobotka et al. 1993
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