adsabs/FOCAL huggingface dataset:
A sky survey at multiple frequencies, carried out with the Square Kilometre Array (SKA) could be used for an independent investigation of the controversial dipole anisotropy with a much superior sensitivity and thereby settle the question of the CP, hopefully, in a more decisive manner. In fact it was argued by Crawford (2009) that it is not possible to detect a radio dipole at more than 1σ level (for a presumed radio dipole amplitude equal to the CMBR dipole, i.e. p = 1), in a survey like the NVSS as the latter does not have sufficient number of sources. The conclusion drawn instead was that in order to make a positive detection of a radio dipole we may have to wait for the SKA data, going to sub-µJy flux-density levels, and thus having much larger number of sources, to get a better signal to noise. In spite of this deterrent prediction, a radio dipole at statistically significant level was detected from the NVSS data itself (Singal 2011) which became possible only because the radio dipole amplitude turned out to be actually a factor of ∼4 larger than the CMBR dipole. Although SKA might provide number counts at sub-µJy levels (Schwarz et al. 2015; Bengaly et al. 2019), however, one may need to be wary of possible caveats in using radio source number counts at these flux-density levels as one might start seeing at sub-mJy levels, in addition to the powerful distant radio sources, a substantially increasing fraction of very different populations of radio sources, e.g. nearby normal galaxies, starburst galaxies, and even galactic sources (Windhorst 2003; Padovani 2011; Luchsinger et al. 2015). Instead what would be important is to get surveys at different frequencies from SKA, at a few mJy levels or above where the radio source population may comprise mostly powerful radio galaxies and quasars, and then investigate the dipoles to see how genuine is the difference in dipoles from surveys at widely separated frequency bands like that seen in the NVSS and TGSS dipoles. The multiple frequency flux-density measurements should also allow for the chosen sample a direct estimate of an optimum value of the spectral index, that enters in the expression for the dipole amplitude. The question of CP could be resolved in a positive manner if it is found that multiple-frequency radio source surveys yield dipoles consistent with the CMBR dipole, though it would still remain to be explained why the presently determined dipoles are not consistent with that. However, in case it does turn out that the SKA surveys with better statistical accuracies also yield dipole magnitudes which are significantly different from the CMBR dipole, even though might be pointing along the CMBR dipole direction, as is seen in the presently determined dipoles, then it will certainly be a big problem for the CP, and consequently all conventional cosmological models, including the ones dealing with the question of dark energy, could be in serious jeopardy.
Citation: Bengaly et al. 2019
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The filtered MHD equations read
11







12





where we sum over repeated indices, and
13







14







15







16





denote the inertial (I), Maxwell (M), advective (A), and dynamo (D) subfilter-scale stresses, respectively. Despite their common origin through the electric field in the induction equation, we here treat 





 and 





 separately, in order to disentangle the effects of magnetic-field-line advection, encoded in 





, and magnetic-field-line stretching, encoded in 





. Usually, the magnetic subscale stress refers to the difference 





 (Aluie 2017; Offermans et al. 2018). Equations (11) and (12) differ from expressions for the filtered MHD equations found elsewhere by an additional projection of the coupling terms. The latter ensures that the dynamics defined by Equations (11) and (12) are confined to the same finite-dimensional subspace Ωℓ of the original domain Ω (Buzzicotti et al. 2018; Offermans et al. 2018). At first sight, this formulation suggests that the corresponding evolution equations for kinetic and magnetic energy feature terms are not Galilean invariant, which ought to be avoided as the measured subfilter-scale energy transfers otherwise include unphysical fluctuations (Aluie & Eyink 2009a, 2009b; Buzzicotti et al. 2018). However, the energy balance equations can be expressed in an alternative way by including terms that vanish under spatial averaging and ensure Galilean invariance of all terms (Buzzicotti et al. 2018; Offermans et al. 2018). For a statistically stationary evolution, the spatiotemporally averaged energy budget can then be written as
17







18





where 





 and 





 are the filtered kinetic and magnetic dissipation rates, respectively, and 





 are terms that convert kinetic to magnetic energy 





 and vice versa 





, and
19







20







21







22





denote the four proper energy fluxes, in the sense that they vanish in the limit ℓ → 0, as can be seen from Equations (13)–(16). If positive, the inertial and Maxwell fluxes, 





 and 





 transfer kinetic energy from scales larger than or equal to ℓ to scales smaller than ℓ and vice versa if negative, while the advective and dynamo fluxes, 





 and 





, do so with magnetic energy. Note that there is no interscale energy conversion as the conversion terms 





 and 





 only involve filtered fields; as such they are known as resolved-scale conversion terms (Aluie 2017). The total energy flux is then given by the sum
23
Citation: Buzzicotti et al. 2018
Citation function: Uses
We present the photometry of the companion in Fig. 4 in a color-magnitude diagram. The corresponding numerical values are reported in Table 2. YSES 2b is consistent with a late L to early T spectral type when comparing it to colors of field brown dwarfs from the NIRSPEC Brown Dwarf Spectroscopic Survey (McLean et al. 2003, 2007), the IRTF spectral library (Rayner et al. 2009; Cushing et al. 2005), the L and T dwarf data archive (Knapp et al. 2004; Golimowski et al. 2004; Chiu et al. 2006), and the SpeX Prism Libraries (Burgasser et al. 2004, 2008, 2010; Gelino & Burgasser 2010; Burgasser 2007; Siegler et al. 2007; Reid et al. 2006; Kirkpatrick et al. 2006, 2010; Cruz et al. 2004; Burgasser & McElwain 2006; McElwain & Burgasser 2006; Sheppard & Cushing 2009; Looper et al. 2007, 2010; Muench et al. 2007; Dhital et al. 2011). Object distances were derived from Gaia EDR3 (Gaia Collaboration 2021), the Brown Dwarf Kinematics Project (Faherty et al. 2009), and the Pan-STARRS1 3π Survey (Best et al. 2018). In color-magnitude space, YSES 2b is very close to the innermost three planets of the HR 8799 multi-planetary system (Marois et al. 2008, 2010). These three planets are classified as mid to late L type dwarfs (e.g., Greenbaum et al. 2018), which agrees well with the sequence evolution of the adjacent field brown dwarfs from L to T spectral types3. A similar spectral type in this domain, therefore, seems very likely for YSES 2b, requiring confirmation by measurements at higher spectral resolution. Whereas the masses of the spectrally similar trio of HR 8799 c, d, and e are in the range 7–12 MJup (Wang et al. 2018; Marois et al. 2008, 2010), it is likely that YSES 2b has an even lower mass as the system age of (13.9 ± 2.3) Myr is significantly younger than the age of HR 8799, which is claimed to be member of the Columba association with an age of 30–50 Myr (Zuckerman et al. 2011; Bell et al. 2015). This is supported by the AMES-COND and AMES-dusty models (Allard et al. 2001; Chabrier et al. 2000) that we present in Fig. 4 for a system age of 13.9 Myr. An individual evaluation of these isochrones yielded masses from 5.3 MJup to 8.0 MJup as presented in Table 2. The uncertainties originate from the errors in the system age and planet magnitude that were propagated by a bootstrapping approach with 1000 randomly drawn samples from Gaussian distributions around both parameters. When combining the posterior distributions for the different models and filters we derived a final mass estimate of 

$6.3^{1.6}_{-0.9}\,M_{\mathrm{Jup}}$6.3−0.9+1.6 MJup
 as the 68% confidence interval around the median of the sample. This estimate is based on broadband photometric measurements alone; further spectral coverage of the planetary SED will be important to constrain its effective temperature, luminosity, surface gravity, and mass.
Citation: Marois et al. 2008
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Large spectroscopic and photometric surveys, such as the Sloan Digital Sky Survey (SDSS, York et al. 2000), have revolutionized astrophysics in many fields, but can only deliver a limited view of the star formation activity in the local universe, given that instruments have a small field of view (FoV) in the case of spectroscopic surveys, and a low spectral resolution in the case of photometric ones. In recent years, integral field spectroscopic (IFS) surveys such as the Calar Alto Legacy Integral Field spectroscopy Area (CALIFA, Sánchez et al. 2012a) survey used in this work, have overcome these problems with the use of instruments with larger FoVs and a fully spectral coverage (e.g SAURON, Bacon et al. 2001; ATLAS3D, Cappellari et al. 2011; SAMI, Croom et al. 2012; VENGA, Blanc et al. 2013; and MaNGA, Bundy et al. 2015). However, these surveys still have limitations, such as the lack of a large contiguous observed area to trace the environment of nearby galaxies. They also suffer from selection biases due to the exclusion of galaxies with angular sizes that do not fit in the FoV of the integral field units (IFUs) that need to be considered (Walcher et al. 2014). These problems can be circumvented with multi-filter photometric surveys, which use a set of intermediate and narrow-band filters designed to provide the required spectral information while still covering a large contiguous area. The Javalambre Photometric Local Universe Survey (J-PLUS1, Cenarro et al. 2019) is currently operating to observe thousands of square degrees of the northern sky from the Observatorio Astrofísico de Javalambre (OAJ2) in Teruel, Spain. The survey is being carried out with the 0.83 m JAST/T80 telescope and the panoramic camera T80Cam (Marin-Franch et al. 2015), with a 2 deg2 FoV. A set of twelve broad, intermediate, and narrow-band optical filters is used (Fig. 1 and Table 1), optimized to provide an adequate sampling of the spectral energy distribution (SED) of millions of stars in our galaxy. These SEDs will be required for the photometric calibration of the Javalambre Physics of the accelerating universe Astrophysical Survey (J-PAS3, Benitez et al. 2014). In addition, the position of the filters, the exposure times, and the survey strategy, are suitable to perform science that will expand our knowledge in many fields of astrophysics. Further details on the OAJ, instrumentation, filter set, J-PLUS photometric calibration process, strategy, and several science applications can be found in the J-PLUS presentation paper (Cenarro et al. 2019).
Citation: Cappellari et al. 2011
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In contrast, deep narrow-field surveys can reach more distant UCD populations, enabling measurement of disk structure and a greater proportion of halo and thick disk sources. The majority of deep surveys for UCDs (Table 1) have been undertaken with the Hubble Space Telescope (HST), as these objects often comprise a foreground to extragalactic surveys. Early work in this area includes measurement of M dwarf number counts in the HST Deep Field and Large Area Multi-Color Survey Groth Strip (Gould et al. 1997; Kerins 1997; Chabrier & Mera 1997). Analysis of these samples determined M dwarf thin and thick disk vertical scaleheights of ∼325 pc and ∼650 pc, respectively, and ruled out very low-mass stars as being an appreciable component (1%) of Galactic halo dark matter. Ryan et al. (2005) performed one of the first deep photometric surveys of distant UCDs, identifying 28 candidate L and T dwarfs in 135 arcmin2 of deep imaging data obtained with the HST Advanced Camera for Surveys (ACS) instrument, selected by their i − z colors to a limiting magnitude of z  25. They determined a thin disk vertical scaleheight of ∼350 pc, similar to prior measurements of deep M dwarf star counts. (Ryan et al. 2011) subsequently identified 17 candidate late-M, L, and T dwarfs in 232 arcmin2 of HST/Wide Field Camera 3 (WFC3) imaging of the Great Observatories Origins Deep Survey (Giavalisco et al. 2004) using optical and near-infrared color selection, and determined a thin disk vertical scaleheight for these sources of 290 ± 40 pc. Deep ground-based surveys have also identified samples of distant UCDs. Kakazu et al. (2010) identified seven late-L and T dwarfs in 9.3 deg2 of optical and infrared imaging data from the Subaru Suprime-Cam Hawaii Quasar and T dwarf survey to a limiting magnitude of z  23.3, spectroscopically confirming several of the targets. From this small sample, Kakazu et al. (2010) inferred a thin disk vertical scaleheight of ∼400 pc for brown dwarfs. Sorahana et al. (2019) used the larger (130 deg2) and deeper (z  24) Hyper Suprime-Cam Subaru Strategic Program survey (Aihara et al. 2018) to photometrically identify 3,665 L dwarfs, and inferred an average thin disk vertical scaleheight of 340–420 pc. Carnero Rosell et al. (2019) used multi-band imaging data from the Dark Energy Survey (The Dark Energy Survey Collaboration 2005), combined with photometry from wide-field imaging surveys, to photometrically identify and classify 11,745 L0–T9 dwarfs to a limiting magnitude of z ≤ 22, and estimated a thin disk vertical scaleheight of ∼450 pc. Recently, Warren et al. (2021) compiled a sample of 34,000 M7-L3 UCDs by searching over a large area of 3,070 deg2 in the Sloan Digital Sky Survey (SDSS; York et al. 2000) and UKIRT Infrared Deep Sky Survey (UKIDSS) down to J = 17.5, and measured a scaleheight of ∼270 pc. These last three studies, which comprise the largest compilations of UCDs to date, use multiple colors to segregate UCDs from other background sources (Skrzypek et al. 2016).
Citation: Ryan et al. 2011
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The cumulative total absolute magnitude distribution of the comets obeys N(  HT) ∝ 10− αTHT. Since we have imposed that the total brightness of the comets scales as BT ∝ fD2, it is easy to show that the slope of the total absolute magnitude distribution, αT, is equal to the slope of the nuclear absolute magnitude distribution, α. The latter is related to the cumulative size-frequency distribution, N( >D) ∝ D− γ, where γ = 5α. Even though there is a lot of scatter in the D − HT diagram caused by variation in f from one comet to the next (Fernández et al. 1999), there is a clear correlation between D and HT in Fig. 1 which must be caused by the underlying size distribution. For JFCs with diameters between approximately 2 km and 10 km the slope γ ~ 2 (Meech et al. 2004; Snodgrass et al. 2011), corresponding to α = 0.4. The number of JFCs with q  2.5 AU and HT  10.8 is then \hbox{$N_{\rm vJFC}=294_{-235}^{+556}$}NvJFC=294-235+556, about three times higher than the number reported in Levison & Duncan (1997) and Di Sisto et al. (2009). This is likely to be a lower limit because of the aforementioned incompleteness. However, the fading alters the mean active lifetime, τvFJC, as well. From the output of our simulations and using the delayed power law we computed a weighted mean period of JFCs with q  2.5 AU of 7.94 yr and a corresponding active lifetime \hbox{$\tau_{\rm vJFC} =1969^{+7479}_{-1540}$}τvJFC=1969-1540+7479 yr, lower than previous estimates (Di Sisto et al. 2009; Duncan & Levison 1997; Fernández et al. 2002). Following Brasser & Morbidelli (2013) the corresponding number of objects in the scattered disc with this updated active lifetime, taking into account the uncertainties in all relevant quantities, is then \hbox{$N_{\rm SD}= 5.9^{+2.2}_{-5.1} \times 10^9$}NSD=5.9-5.1+2.2×109. That same work computed an Oort cloud population of NOC = (7.6 ± 3.3) × 1010 for objects with D> 2.3 km. From our new analysis the Oort cloud to scattered disc population ratio turns out to be 13\hbox{$_{-11}^{+77}$}+77-11, which is consistent with the ratio of 12 ± 1 from simulations (Brasser & Morbidelli 2013). Thus, it is likely that the Oort cloud and scattered disc formed at the same time from the same source, and thus is consistent with a formation during the giant planet instability.
Citation: Fernández et al. 1999
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Following the first detection by ROSAT (Komossa & Bade 1999; Bade, Komossa & Dahlem 2016), about 50 TDEs have been observed (Komossa 2015) in hard X-ray (Bloom et al. 2011; Burrows et al. 2011; Cenko et al. 2012; Pasham et al. 2015), soft X-ray (Komossa & Bade 1999; Donley et al. 2002; Esquej et al. 2008; Maksym et al. 2010; Saxton et al. 2012, 2017; Bade et al. 2016), UV (Stern et al. 2004; Gezari et al. 2006, 2008, 2009) and optical (van Velzen et al. 2011; Gezari et al. 2012; Arcavi et al. 2014; Chornock et al. 2014; Holoien et al. 2014; Vinko et al. 2015) wavelengths. Some of the observed TDEs exhibit unusual properties. In particular, one of the detected TDEs shows an excess of variability in its light curve (Saxton et al. 2012) which can be explained if the black hole is actually a binary with a mass of 106 M⊙, mass ratio of 0.1 and semimajor axis of 0.6 milliparsecs (Liu, Li & Komossa 2014). This candidate appears to have one of the most compact orbits among the known SMBH binaries and has overcome the ‘final parsec problem’ (Colpi 2014). Upon coalescence, it will be a strong source of gravitational wave emission in the sensitivity range of the evolved Laser Interferometer Space Antenna (eLISA). Three other TDEs appear to be very bright in X-rays with peak soft X-ray isotropic luminosity being highly super-Eddington (Burrows et al. 2011; Cenko et al. 2012; Brown et al. 2015), while follow-up observations showed that these events were also associated with bright, compact, variable radio synchrotron emission (Zauderer et al. 2011; Cenko et al. 2012). The observed high X-ray luminosity can be explained if the tidal disruption of stars in these cases powered a highly beamed relativistic jet pointed at the observer (Tchekhovskoy et al. 2014). Based on these three observations, Kawamuro et al. (2016) concluded that 0.0007 per cent–34 per cent of all TDEs source relativistic jets, while Bower et al. (2013) and van Velzen et al. (2013) estimated that ≲10 per cent of TDEs produce jetted emission at the observed level. Formation of jets in TDEs is a topic of active research, e.g. works by Metzger, Giannios & Mimica (2012), Mimica et al. (2015) and Generozov et al. (2017).
Citation: Colpi 2014
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There have been previous studies that utilized coronal extreme ultraviolet (EUV) images in combination with models to try to more accurately determine the magnetic field. Conlon and Gallagher (Conlon & Gallagher 2010) used Extreme Ultraviolet Imager (EUVI) images to choose the best value of the parameter α in an LFFF model of a coronal active region. Aschwanden and co-authors (Aschwanden & Sandman 2010; Aschwanden 2013; Aschwanden & Malanushenko 2013) created NLFFF models of active regions by forward-fitting the underlying magnetograms with sets of buried magnetic monopoles and selecting the corresponding α values for each monopole that produced the greatest agreement with coronal loops traced in EUVI images. Malanushenko and co-authors (Malanushenko et al. 2009, 2012) have presented a method for deriving an NLFFF model from sparsely distributed EUV loop observations. These studies have focused on modeling the field in active regions, where the high density results in bright EUV emission and the limited size of the region allows for a reasonable number of free parameters. Additionally, the complexity of these methods suggests that their primary application would be the detailed study of a specific region of interest, rather than casual production of models for programmatic use. In contrast, the purpose of our study has been to develop a method for the fast production of global coronal magnetic field models based on widely available synoptic magnetograms and coronal images. Global models are necessary for studies on a wide array of topics, including the connectivity of active regions (Tadesse et al. 2012; Schrijver et al. 2013), the topology of the corona through the solar cycle (Wang & Sheeley 2003; Platten et al. 2014), and as a larger context for studies of coronal activity in localized regions (Conlon & Gallagher 2010; Schrijver et al. 2013). They are also instrumental for global heliospheric simulation and interpreting in situ measurements by upcoming near-Sun missions, Solar Orbiter (SO) and Solar Probe Plus (SPP).
Citation: Malanushenko et al. 2009
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By considering the UV emission at several wavelengths, we have been able to reconstruct the evolution of the EFR at different layers using radiance maps. The optically thin view provided by the O i λ1355.6 line (Lin & Carlsson 2015) images the AFS that formed above the EFR. AFSs are typically observed in absorption in the chromospheric layers during flux emergence and reflect the serpentine nature of the emerging fields (Bruzek 1980; Spadaro et al. 2004; Zuccarello et al. 2005; Murabito et al. 2017). They also can reconnect with the ambient field (e.g., Zuccarello et al. 2008; Tarr et al. 2014; Su et al. 2018). Here the AFS appears in emission when observed in the O i λ1355.6 line, being brighter than the background. Some brightness enhancements are found along the AFS, suggesting the occurrence of small-scale energy release events related to the reconnection of the emerging field lines with the ambient field (see, e.g., Huang et al. 2018). The view of optically thick Mg ii k and C ii λ1335 lines (Leenaarts et al. 2013; Rathore et al. 2015) offers the possibility to see the counterpart of the AFS in the upper chromosphere. Threads observed in absorption, departing from the AFS, cover the whole structure. It should be stressed that the reconstructed radiance maps image the EFR along the entire IRIS scan: this means that the individual threads at every single slit position along the x-direction were only transiently observed. From the comparison with IRIS SJIs in the 2796 Å passband, it can be deduced that threads correspond to the surges, being viewed as individual ejections in slice imaging. The westernmost part of the UV burst, being not covered by threads, is seen as a compact brightening in the Mg ii k and C ii λ1335 radiance maps, in the latter having a higher contrast with respect to the background. Conversely, the optically thin emission in the Si iv λλ1402 and 1394 lines clearly illustrates the UV burst and other bright knots in the EFR area. Apparently, threads have no counterpart at Si iv λλ1402 and 1394 formation heights, although fluffy elongated structures appear in the northern part of the UV burst. Finally, dark elongated absorption structures are distinctly visible in the SDO/AIA 193 filtergrams, which are highly reminiscent of the threads seen by IRIS. To their west, a compact brightening cospatial to the UV burst is also detected, being not obscured by such structures.
Citation: Tarr et al. 2014
Citation function: Background