adsabs/FOCAL huggingface dataset:
Flattened distributions of very likely co-orbiting satellite galaxies around the MW (Lynden-Bell 1976, 1982; Kroupa, Theis & Boily 2005; Pawlowski, Pflamm-Altenburg & Kroupa 2012) and M31 (Metz, Kroupa & Jerjen 2007; Ibata et al. 2013) have long posed a challenge to our understanding of galaxy formation in the ΛCDM context. Recent proper motion data confirm that most of the classical MW satellites do indeed have a common orbital plane (Pawlowski, Kroupa & Jerjen 2013; Pawlowski & Kroupa 2020) aligned with the plane normal defined by the satellite positions alone (Santos-Santos, Domínguez-Tenreiro & Pawlowski 2020). Their velocities show a very significant bias towards the tangential direction, as occurs for a rotating disc (Cautun & Frenk 2017). Proper motions of two M31 satellite plane members indicate that this structure is likely also coherently rotating (Sohn et al. 2020), as suggested by the RVs of satellites in this nearly edge-on structure (Ibata et al. 2013). After careful consideration of several proposed scenarios for how primordial CDM-rich satellites might end up in a thin plane, Pawlowski et al. (2014) concluded that none of them agree with observations for either the MW or M31. Structures as extreme as those observed are exceedingly rare in cosmological simulations (Ibata et al. 2014; Pawlowski & McGaugh 2014b), including hydrodynamical simulations (Ahmed, Brooks & Christensen 2017; Shao, Cautun & Frenk 2019; Pawlowski & Kroupa 2020) and simulations which model the effects of a central disc galaxy (Pawlowski et al. 2019). The arguments raised by Metz et al. (2009) and Pawlowski et al. (2014) against the group infall and filamentary accretion scenarios were later independently confirmed by Shao et al. (2018) using the EAGLE hydrodynamical cosmological simulation (Crain et al. 2015; Schaye et al. 2015). For a recent review of the satellite plane problem, we refer the reader to Pawlowski (2018), who considered both LG satellite planes and the recently discovered one around Centaurus A (Müller et al. 2018, 2021).
Citation: Santos-Santos, Domínguez-Tenreiro & Pawlowski 2020
Citation function: Background; Background
The cosmic web, consisting of haloes, voids, filaments, and walls in large-scale structure is predicted by the cold dark matter model (Bond, Kofman & Pogosyan 1996; Pogosyan et al. 1998) and confirmed by large galaxy surveys (e.g. de Lapparent, Geller & Huchra 1986; Colless et al. 2003; Alam et al. 2015). Among these large-scale structures, the underdensities of the universe, i.e. cosmic voids, have been shown to have great potential for constraining dark energy and testing theories of gravity via several measurements. These measurements include: distance measurement via the Alcock–Paczyński test (Ryden 1995; Lavaux & Wandelt 2012; Sutter et al. 2014), weak gravitational lensing of voids (Krause et al. 2013; Clampitt & Jain 2015; Melchior et al. 2014; Gruen et al. 2016; Sánchez et al. 2016), the signal of the integrated Sachs–Wolfe effect associated with voids (Sachs & Wolfe 1967; Granett, Neyrinck & Szapudi 2008; Nadathur, Hotchkiss & Sarkar 2012; Flender, Hotchkiss & Nadathur 2013; Ilić, Langer & Douspis 2013; Cai et al. 2014; Planck Collaboration XIX 2014; Aiola, Kosowsky & Wang 2015; Kovács & Granett 2015; Planck Collaboration XXI 2015), void ellipticity as a probe for the dark energy equation of state (Lee & Park 2009; Lavaux & Wandelt 2010; Bos et al. 2012; Pisani et al. 2015; Sutter et al. 2015), void abundances and profiles for testing theories of gravity and cosmology (Li, Zhao & Koyama 2012; Clampitt, Cai & Li 2013; Barreira et al. 2015; Cai, Padilla & Li 2015; Lam et al. 2015; Massara et al. 2015; Zivick et al. 2015), coupled dark energy (Pollina et al. 2016), the nature of dark matter (Yang et al. 2015), baryon acoustic oscillations in void clustering (Kitaura et al. 2016; Liang et al. 2016), and redshift-space distortions in voids (Hamaus et al. 2015, 2016; Cai et al. 2016). Despite their popularity and great potential as a cosmological tool, a gap of knowledge between the evolution of individual voids through simulations and observations versus theory still persists. How voids evolve from the initial conditions and how dark energy or alternative theories of gravity shape this process still lacks a complete analytical understanding. As with the formation history of haloes, the initial conditions and evolution history of voids sets the base for their two fundamental properties: profile and abundance. As these are crucial for constraining cosmological parameters, it is therefore important to bridge the gap between theory and observations. This is the main goal of our study.
Citation: Sutter et al. 2014
Citation function: Motivation
Scheeres (2007) and Nesvornỳ & Vokrouhlickỳ (2007) established averaging methods for YORP effects experienced by small bodies (mostly asteroids) taking real-time insolation and shape into account. However, unlike thermal radiation, as Fig. 2 shows, the CO (or H2O) production rate variation versus solar distance is too complex to be written into a linear or polynomial formula (over the entire range we want to investigate). Sidorenko, Scheeres & Byram (2008) applied the averaging method to obtain evolutionary equations in order to study the long-term variations in the nucleus spin state induced by outgassing torques, but the illumination variation is not considered in their simplified model. There are further analytical approaches described in the literature (Samarasinha & Mueller 2013; Steckloff & Jacobson 2016; Steckloff & Samarasinha 2018), although these models predicted a change in the spin state of the nucleus without taking into consideration the exact 3D shape model and its variation induced by mass loss. Therefore, to our knowledge, there exists no approximate framework that is able to combine spin and mass loss together with orbital evolution for the 3D shapes (accounting for shadowing and self-heating) we are exploring in this paper. Currently, only fully numerical schemes are appropriate to investigate sublimation torques in our context. At the same time, it is not feasible to include such numerically expensive considerations when exploring the parameter space of orbits, mass-loss function and axis orientations. Therefore, in this work, we consider the rotation of the nucleus only for the stable case, without taking into consideration the wobbling rotation excitation and the change in spin states as a result of sublimation torque. However, we plan to perform these in the future, relying on the knowledge gained from physically and scientifically interesting cases in this work. As a general remark, the spin (and/or orientation) changes induced by sublimation torque are not expected to play a role only if the orientation variation time-scale is significantly larger than the time-scale of shape modification. However, if the time-scale is significantly shorter, new results are expected as the variation period of θ and φ might bring new periodical effects. A tumbling spin state with large procession angle or even a chaotic rotation may average the mass loss on the surface to yield an ‘averaged’ shape as a result. Therefore, if a nucleus exhibits an asymmetry shape believed to be driven by sublimation activity, it would indicate that the nucleus rotates in a stable stage for a long-term period in its dynamical history. In other words, this implies that the time-scale of wobbling excitation of such objects might be much longer than the one for shape modification.
Citation: Samarasinha & Mueller 2013
Citation function: Background; Differences
The temperature of the IGM can be measured using the effect of Doppler broadening on the forest of Ly α absorption line seen in the spectra of high-redshift quasars and galaxies (Rauch 1998; Savaglio, Panagia & Padovani 2002). Traditionally, the absorbing clouds were treated as being distinct and fitting Voigt profiles (e.g. van de Hulst & Reesinck 1947; Carswell & Webb 2014; Webb, Carswell & Lee 2021) to features seen in spectra leads to two parameters, column densities and temperatures (e.g. Hu et al. 1995). However, since the identification of the Ly α forest in hydrodynamic simulations (Cen et al. 1994; Zhang, Anninos & Norman 1995; Hernquist et al. 1996), it was realized that in the context of cosmological models for structure formation, the Ly α forest is due to a fluctuating, continuous IGM (e.g. Bi 1993; Weinberg et al. 2003). Because of this, Hubble flow is the major source of broadening, and fitting the width of features with a thermally broadened profile of a discrete object will not yield the temperature directly. Many other techniques have therefore been developed to constrain the IGM temperature from the Ly α forest. One is the relatively straightforward use of Voigt profile fit parameters to try to find the envelope that corresponds to a minimum IGM temperature (e.g. Garzilli, Theuns & Schaye 2020). Others include wavelet transforms (Meiksin 2000; Garzilli et al. 2012), or measuring statistical properties of the Ly α forest flux, such as the power spectrum (Croft et al. 1998; Lai et al. 2006), which respond to the small-scale smoothing that results from increased IGM temperatures. More recent ideas include the reconstruction techniques of Müller, Behrens & Marsh (2021) that use 3D tomographic data. In the current work, we will use a neural network (NN, see below) trained on simulated Ly α spectra to infer the temperature from the smoothness of absorption features. We will be looking in particular for discontinuous T jumps that could result from discrete sources of heating such as quasars reionizing He ii. We note that the temperature of gas will also influence the pressure smoothing scale (Gnedin & Hui 1998), which physically makes gaseous structures smoother than their underlying dark matter counterparts (Peeples et al. 2010). In our current preliminary work, we will not model this effect (see also the approach of McQuinn et al. 2011, who used a similar approximation), so that the smoothing of absorption features will be entirely attributed to Doppler broadening.
Citation: Weinberg et al. 2003
Citation function: Background; Background
The origin of giant pulses has been remaining a mystery since the discovery of giant pulses from Crab pulsar (Staelin & Reifenstein 1968). The generation of giant pulse activity was pointed to be an intrinsic phenomenon within the pulsar (Hankins 1971). The giant pulses are supposed to be the product of induced Compton scattering of the radio radiation off the plasma in the pulsar magnetosphere (Petrova 2006). The extremely high intensity is as well caused by an enhanced number of charges partaking in the nonthermal, coherent radiation processes (Hankins et al. 2003). Alternatively, the origination of giant pulses is proposed from the coherent instability of plasma near the magnetic equator of light cylinder (Wang et al. 2019). Singal & Vats (2012) suggested that the giant pulse emission and nulling may be opposite manifestations of the same physical process. The giant pulses are suggested to occur in pulsars with extremely high magnetic fields at the light cylinder of BLC > 105 G (Cognard et al. 1996). Therefore, the giant pulses are proposed to originate near the light cylinder (Istomin 2004). However, the giant pulses are also detected in the pulsars with ordinary magnetic fields at the light cylinder of BLC  100 G, such as PSRs B0031−07 (Kuzmin & Ershov 2004), B1112+50 (Ershov & Kuzmin 2003), J1752+2359 (Ershov & Kuzmin 2005), B0950+08 (Smirnova 2012), B0656+14 (Kuzmin & Ershov 2006), B1237+25 (Kazantsev & Potapov 2017), and B0301+19 (Kazantsev et al. 2019), and it does not seem to support the high BLC hypothesis. The Vela giant micropulse emission physics maybe independent on the high magnetic field at the light cylinder. Although Vela’s BLC is about 20 times smaller than that of PSR B1937+21 and the Crab pulsar, it is still in the top 5% of pulsars with BLC estimate. The giant pulses from PSR J1824−2452A occur in narrow phase windows that correlate in phase with X-ray emission, and the two emission phenomena likely originate from the similar magnetospheric regions but not the same physical mechanism (Knight et al. 2006). In order to reveal the nature of the giant micropulses, simultaneous radio and X-ray observations on the Vela pulsar will be required.
Citation: Wang et al. 2019
Citation function: Background
We constructed a sample of artificial stars representing the TT and HAeBe regime by using synthetic models of stellar atmospheres (Kurucz 1993). The properties of each object are provided in Table 1. Columns two and three show the stellar luminosity and effective temperature. From these, the stellar radii was derived, spanning between 0.7 and 4 R⊙ (column 4). The stellar masses (column 5) were derived assuming log g = 4, and cover the 0.2–6 M⊙ range. Magnetospheric accretion (MA) shock modelling was carried out for each star by adding (blackbody) accretion contributions to the photospheric (Kurucz) spectra (see e.g. the reviews in Calvet, Hartmann & Strom 2000; Mendigutía 2013). Two representative examples are presented in Fig. 2 (left-hand panel). The shock model was applied following the usual recipes for both the TTs and HAeBes, and we refer the reader to Calvet & Gullbring (1998); Mendigutía et al. (2011) and Fairlamb et al. (2015) for further details. Three different values for the UV excess in the Balmer region of the spectra (from ∼3500 to 4000 Å, as defined in Mendigutía et al. 2013) were modelled for each object assuming typical values for the inward flux of energy carried by the accretion columns (1012 erg cm2 s−1) and the disc truncation radius (5R*): a ‘maximum’ excess (0.70 mag), whose corresponding accretion contribution is Lacc ∼ L* for L* ≥ L⊙; a ‘minimum’ excess (0.01 mag) representative of the observational limit, and whose corresponding accretion contribution is Lacc ∼ 0.01L* for L* ≥ L⊙; and finally, a ‘typical’ excess in-between the two previous (0.12 mag). The resulting accretion luminosities are shown in the last three columns of Table 1. These are plotted versus the corresponding L* values (blue diagonal dashed lines in Fig. 1), matching the overall distribution of data. We note that excesses larger than 0.70 mag could still be measured for the less luminous sources (L* ≤ L⊙) without reaching the upper bound (Lacc ∼ L*).
Citation: Mendigutía 2013
Citation function: Uses
Coronal loops are curvilinear structures in the outer layer of the solar atmosphere, and they are formed by thermal plasmas confined by magnetic fields and well reflect the coronal magnetic field configurations. Because a number of active phenomena in the solar atmosphere, such as flares, the solar wind, coronal mass ejection (CME) and coronal oscillation, are associated with the coronal magnetic field, instead of direct observation of the coronal magnetic field, solar physicists are able to indirectly obtain the structure and evolution of the coronal magnetic field by observing and studying the kinetic characteristics of coronal loops. On the other hand, when flares and CME occur, the coronal magnetic field structure will undergo drastic changes, which will result in the oscillation of coronal loops (Li, Liu & Tam 2017). Therefore, on the basis of the oscillation of coronal loops, especially their oscillation characteristics in frequency, phase and attenuation coefficient, solar physicists can further understand the relationships between the coronal magnetic field, flares and CME (Aschwanden et al. 1999; Jain, Maurya & Hindman 2015) and obtain corresponding physical parameters associated with oscillating coronal loops (Aschwanden & Schrijver 2011). Meanwhile, the study on coronal loops is also useful for us to well understand the properties of coronal plasmas (Parnell & De Moortel 2012), plasma motion inside coronal loops (Winebarger, DeLuca & Golub 2001; Uritsky et al. 2013; Zhou & Liang 2016), the propagation of MHD waves in coronal loops (Wang, Ofman & Davila 2013), the evolution of active regions (Yan et al. 2012) and coronal heating (Aschwanden et al. 2007a; Aschwanden & Peter 2017). In addition, in modelling the coronal magnetic field, the observed coronal loops can be taken as a constraint condition so as to obtain more realistic extrapolated results of the non-linear force-free (NLFF) magnetic field model (Su et al. 2009; Aschwanden 2013). In particular, along with the enrichment of observational data in multiple wavebands, the classification and study of different temperatures and densities of the coronal loops will be further expanded, and the meaningful physical mechanism of these phenomena will also be obtained (Aschwanden & Boerner 2011; Huang et al. 2012; Aschwanden et al. 2013a). However, it must be emphasized that the current observational data of coronal loops are just a two-dimensional (2D) projective result of the real shape of coronal loops on to the plane of sky. Therefore, to obtain the genuine shape of coronal loops, a three-dimensional (3D) reconstruction of coronal loops is needed (Aschwanden et al. 2008b). It is desirable to reconstruct the real shape of coronal loops, resulting from the fact that identical coronal loops from the 2D observation data of multiple viewing angles (the observation data of the Solar Terrestrial Relations Observatory (STEREO), Uritsky et al. 2013) can be detected and extracted.
Citation: Aschwanden et al. 1999
Citation function: Motivation; Motivation
In the turbulent gaseous halos of clusters, groups, and galaxies (particularly massive ones), extended filaments and clouds condense out of the hot plasma in a top-down nonlinear23

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This nonlinear condensation process has properties significantly different from those of classic linear thermal instability (TI); the latter is mainly concerned with small overdensities overcoming buoyancy oscillations (e.g., Field 1965; Balbus & Soker 1989; Burkert & Lin 2000; Pizzolato & Soker 2005; McCourt et al. 2012—more in Section 5).
 condensation cascade, forming a chaotic multiphase rain. The thermal state and kinematics of the progenitor hot plasma halo drive the formation and evolution of all the condensed structures, which inherit some of the parent properties. Part of the inner condensed gas eventually accretes onto the central supermassive black hole (SMBH), igniting the feedback response and efficiently self-regulating the entire atmosphere over several gigayears (e.g., Gaspari et al. 2011a, 2011b, 2012a, 2012b; Li & Bryan 2014; Barai et al. 2016; Soker 2016; Yang & Reynolds 2016; Meece et al. 2017; Voit et al. 2017). This feeding process is known as chaotic cold accretion (CCA; Gaspari et al. 2013b) and can intermittently boost the accretion rates up to 100× the hot (Bondi) rate. If turbulence is subdominant, the halo tends instead to condense in a disk structure (due to the preservation of angular momentum), reducing feeding and feedback—this regime is more important for low-mass, spiral galaxies.24

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The top-down rain differs from the bottom-up condensation in the disk of spiral galaxies, where the hot/warm phase is created in situ by supernovae, which drive compressive, non-solenoidal turbulence (e.g., McKee & Ostriker 1977; Kim et al. 2013). Nevertheless, the two complement each other, producing multiphase gas in the more extended halo and in the disk, respectively. Massive galaxies, groups, and clusters, lacking an extended disk (e.g., Werner et al. 2014), typically reside in the top-down condensation regime.
 Finally, if the entropy of the halo (or cooling time) becomes too high, the whole atmosphere may simply prevent condensation and remain hot for an extended period of time, dramatically stifling the feedback response. Overall, assessing the dynamical state of the multiphase halos is crucial to understand the past and to predict the future evolution of cosmic structures.
Citation: Meece et al. 2017
Citation function: Background
Jovian electrons were used as test particles to model the charged-particle transport computationally (see e.g. Chenette et al. 1977; Conlon 1978; Fichtner et al. 2000; Zhang et al. 2007, and references therein) to ascertain the diffusion coefficients parallel and perpendicular to the Heliospheric Magnetic Field (HMF). This was usually done by comparing computed with measured electron intensities at Earth during periods of good or bad magnetic connection. Furthermore, given the demonstrated sensitivity of computed low-energy galactic electron intensities to various turbulence quantities (see Engelbrecht & Burger 2010, 2013; Engelbrecht 2019), it may be possible to draw conclusions from Jovian electrons to better understand the behaviour of those quantities in regions of the heliosphere where spacecraft observations of this character do not exist (see, e.g., Engelbrecht 2017). Since these transport parameters and the diffusion coefficients they depend on are spatially dependent, the time that particles reside in a certain part of the heliosphere may yield significant insights to the modulation of GCRs as well. Florinski & Pogorelov (2009) showed this dependency for GCR protons, investigating the time they spend in the heliotail, in the heliosheath, and in the solar wind within the termination shock, respectively. Utilising both galactic electrons and protons, Strauss et al. (2011a) focussed on the connection between thetotal propagation time and energy losses. They find a significant non-linear dependency on the total propagation times, which is strong enough to influence also the observations of Jovian electrons. These energy losses are entirely caused by adiabatic effects as other possible influences such as particle-particle interactions are negligible in the TPE due to a lack of significance in the interplanetary medium. As the adiabatic energy changes d E∕d t ~−2∕3 ⋅ EuSW∕r are connected to the radial position, the corresponding energy loss rate per step only depends on the temporal step size Δs and the radial position after the step. The radial direction of the step is thereby irrelevant. This leads to particles spending more simulation time at small radii losing more energy and implicitly to a statistical connection between the average energy losses and the particle’s mean free paths.
Citation: Engelbrecht & Burger 2010
Citation function: Uses; Uses