ShantanuT01/DACTYL-Pretraining huggingface dataset:
We present measurements of broad emission lines and virial estimates of supermassive black hole masses ($M_{BH}$) for a large sample of ultra-hard X-ray selected active galactic nuclei (AGNs) as part of the second data release of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes $M_{BH}$ estimates for a total 689 AGNs, determined from the H$\alpha$, H$\beta$, $MgII\lambda2798$, and/or $CIV\lambda1549$ broad emission lines. The core sample includes a total of 512 AGNs drawn from the 70-month Swift/BAT all-sky catalog. We also provide measurements for 177 additional AGNs that are drawn from deeper Swift/BAT survey data. We study the links between $M_{BH}$ estimates and line-of-sight obscuration measured from X-ray spectral analysis. We find that broad H$\alpha$ emission lines in obscured AGNs ($\log (N_{\rm H}/{\rm cm}^{-2})> 22.0$) are on average a factor of $8.0_{-2.4}^{+4.1}$ weaker, relative to ultra-hard X-ray emission, and about $35_{-12}^{~+7}$\% narrower than in unobscured sources (i.e., $\log (N_{\rm H}/{\rm cm}^{-2}) < 21.5$). This indicates that the innermost part of the broad-line region is preferentially absorbed. Consequently, current single-epoch $M_{BH}$ prescriptions result in severely underestimated ($>$1 dex) masses for Type 1.9 sources (AGNs with broad H$\alpha$ but no broad H$\beta$) and/or sources with $\log (N_{\rm H}/{\rm cm}^{-2}) > 22.0$. We provide simple multiplicative corrections for the observed luminosity and width of the broad H$\alpha$ component ($L[{\rm b}{\rm H}\alpha]$ and FWHM[bH$\alpha$]) in such sources to account for this effect, and to (partially) remedy $M_{BH}$ estimates for Type 1.9 objects. As key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift Universe.
Magnetic confinement of stellar winds leads to the formation of magnetospheres, which can be sculpted into Centrifugal Magnetospheres (CMs) by rotational support of the corotating plasma. The conditions required for the CMs of magnetic early B-type stars to yield detectable emission in H$\alpha$ -- the principal diagnostic of these structures -- are poorly constrained. A key reason is that no detailed study of the magnetic and rotational evolution of this population has yet been performed. Using newly determined rotational periods, modern magnetic measurements, and atmospheric parameters determined via spectroscopic modelling, we have derived fundamental parameters, dipolar oblique rotator models, and magnetospheric parameters for 56 early B-type stars. Comparison to magnetic A- and O-type stars shows that the range of surface magnetic field strength is essentially constant with stellar mass, but that the unsigned surface magnetic flux increases with mass. Both the surface magnetic dipole strength and the total magnetic flux decrease with stellar age, with the rate of flux decay apparently increasing with stellar mass. We find tentative evidence that multipolar magnetic fields may decay more rapidly than dipoles. Rotational periods increase with stellar age, as expected for a magnetic braking scenario. Without exception, all stars with H$\alpha$ emission originating in a CM are 1) rapid rotators, 2) strongly magnetic, and 3) young, with the latter property consistent with the observation that magnetic fields and rotation both decrease over time.
We analyze the joint extremal behavior of $n$ random products of the form $\prod_{j=1}^m X_j^{a_{ij}}, 1 \leq i \leq n,$ for non-negative, independent regularly varying random variables $X_1, \ldots, X_m$ and general coefficients $a_{ij} \in \mathbb{R}$. Products of this form appear for example if one observes a linear time series with gamma type innovations at $n$ points in time. We combine arguments of linear optimization and a generalized concept of regular variation on cones to show that the asymptotic behavior of joint exceedance probabilities of these products is determined by the solution of a linear program related to the matrix $\mathbf{A}=(a_{ij})$.
We are interested in finding for which positive integers $D$ we have rational solutions for the equation $x^3+y^3=D.$ The aim of this paper is to compute the value of the $L$-function $L(E_D, 1)$ for the elliptic curves $E_D: x^3+y^3=D$. For the case of $p$ prime $p\equiv 1\mod 9$, two formulas have been computed by Rodriguez-Villegas and Zagier. We have computed formulas that relate $L(E_D, 1)$ to the square of a trace of a modular function at a CM point. This offers a criterion for when the integer $D$ is the sum of two rational cubes. Furthermore, when $L(E_D, 1)$ is nonzero we get a formula for the number of elements in the Tate-Shafarevich group and we show that this number is a square when $D$ is a norm in $\mathbb{Q}[\sqrt{-3}]$.
Recently discovered models of ghost-free massive gravity and bigravity are characterized by a non-trivial potential that gives rise to a rich vacuum structure. We review maximally symmetric vacua of the de Rham-Gabadadze-Tolley (dRGT) massive gravity and of the Hassan-Rosen (HR) bigravity, and discuss their perturbative stability. In particular, we discuss perturbations about self-accelerating vacua in HR bigravity, and argue that, analogously to what was found in the case of dRGT gravity, some of them contain strongly coupled modes. We then show that it is impossible to construct regular instantons connecting different classically stable vacua of dRGT gravity without violating energy conservation or the null energy condition.
A problem of the cosmological evolution of the IGM is recalled and a necessity to find distant (z>0.5) giant radio galaxies (GRGs) with the lobe energy densities lower than about 10^{-14} J m^{-3} to solve this problem is emphasized. Therefore we undertake a search for such GRGs on the southern sky hemisphere using the SALT. In this paper we present a selected sample of the GRG candidates and the first deep detections of distant host galaxies, as well as the low-resolution spectra of the galaxies identified on the DSS frames. The data collected during the Performance Verification (P-V) phase show that 21 of 35 galaxies with the spectroscopic redshift have the projected linear size greater than 1 Mpc (for H_{0}=71 km\s\Mpc). However their redshifts do not exceed the value of 0.4 and the energy density in only two of them is less than 10^{-14} J m^{-3}. A photometric redshift estimate of one of them (J1420-0545) suggests a linear extent larger than 4.8 Mpc, i.e. a larger than that of 3C236, the largest GRG known up to now.
Part I of this article studied the specific heats of planar alternating layered Ising models with strips of strong coupling $J_1$ sandwiched between strips of weak coupling $J_2$, to illustrate qualitatively the effects of connectivity, proximity, and enhancement in analogy to those seen in extensive experiments on superfluid helium by Gasparini and coworkers. It was demonstrated graphically that finite-size scaling descriptions hold in a variety of temperature regions including in the vicinity of the two specific heat maxima. Here we provide exact theoretical analyses and asymptotics of the specific heat that support and confirm the graphical findings. Specifically, at the overall or bulk critical point, the anticipated (and always present) logarithmic singularity is shown to vanish exponentially fast as the width of the stronger strips increases.
For an odd prime p and a number field F containing a primitive p-th root of unity, we describe the Kummer radical A_F of the first layers of all the Z_p-extensions of F in terms of universal norms of p-units along the cyclotomic tower of F . We also study "twisted" radicals related to AF .
When a single magnetic adatom is deposited on a surface of a metal, it affects the charge and spin texture of the electron gas surrounding it. The screening of the local moment by conduction electrons gives rise to the Kondo effect. Here we investigate the effect of the Rashba spin orbit coupling on the local magnetization density of states (LMDOS) around a Cobalt impurity on a Au(111) surface in a magnetic field. We show that the in-plane component of the LMDOS is exclusively associated with the Rashba spin orbit interaction. This observation can be experimentally exploited to confirm the presence of the Rashba effect on surfaces, such as Au(111), by performing spin-polarized STM measurements around the Kondo impurity.
Let $P$ be a finite poset with an element $s$ such that (1) for all $x\in P$, either $s\vee x$ or $s\wedge x$ exists; and (2) for all $x,y\in P$ such that $x<y$, if $s\wedge x$ does not exist but $s\wedge y$ does exist, then $(s\wedge y)\vee x$ exists. Kozlov, the winner of the 2005 European Prize in Combinatorics ("for deep combinatorial results obtained by algebraic topology and particularly for the solution of a conjecture of Lov\'asz"), conjectured in the 1998 Proceedings of the American Mathematical Society that the order complex of $P$ is non-evasive. We prove this conjecture.
In this paper, we revisit the weak gravitational lensing of CMB. The key point is that the deflection angle of CMB photon varies with the redshift. From this we obtain a set of modified power spectra. Compared with the ones calculated before, the temperature, the polarization E mode and the cross power spectra correction are of the order $0.01 %$, while the polarization B mode correction is about $0.4 %$ (to $l=2000$).
We compute the matching coefficients between QCD and non-relativistic QCD for external vector, axial-vector, scalar and pseudo-scalar currents up to three-loop order. We concentrate on the non-singlet contributions and present precise numerical results with an accuracy of about ten digits. For the vector current the results from arXiv:1401.3004 are confirmed, increasing the accuracy by several orders of magnitude.
We study the elliptic inclusion given in the following divergence form   \begin{align*}   & -\mathrm{div}\, A(x,\nabla u) \ni f\quad \mathrm{in}\quad \Omega,   & u=0\quad \mathrm{on}\quad \partial \Omega.   \end{align*}   As we assume that $f\in L^1(\Omega)$, the solutions to the above problem are understood in the renormalized sense. We also assume nonstandard, possibly nonpolynomial, heterogeneous and anisotropic growth and coercivity conditions on the maximally monotone multifunction $A$ which necessitates the use of the nonseparable and nonreflexive Musielak--Orlicz spaces. We prove the existence and uniqueness of the renormalized solution as well as, under additional assumptions on the problem data, its relation to the weak solution. The key difficulty, the lack of a Carath\'{e}odory selection of the maximally monotone multifunction is overcome with the use of the Minty transform.
We explore the nature of the long-wavelength mid-infrared (MIR) emission of a sample of 13000 local Type II (narrow-line) Active Galactic Nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS) using 12 and 22 micron photometry from the WISE all-sky survey. In combination with FIRST 1.4 GHz measurements, we show that AGNs divide into two relatively distinct populations or "branches" in the plane of MIR and radio luminosity. Seyfert galaxies lie almost exclusively on a MIR-bright branch (Branch A), while low-ionization nuclear emission line galaxies (LINERs) are split evenly into Branch A and the MIR-faint Branch B. We devise various tests to constrain the processes that define the branches, including a comparison to the properties of pure star-forming (SF) inactive galaxies on the MIR-Radio plane. We demonstrate that the total MIR emission of objects on Branch A, including most Seyfert galaxies, is governed primarily by host star-formation, with about 15% of the 22 micron luminosity coming from AGN-heated dust. This implies that on-going dusty star-formation is a general property of Seyfert host galaxies. We show that the 12 micron broad-band luminosity of AGNs on Branch A is suppressed with respect to star-forming galaxies, possibly due to the destruction of PAHs or deeper 10 microns Si absorption in AGNs. We uncover a correlation between the MIR luminosity and [O III] luminosity in AGNs. This suggests a relationship between the SFR and nuclear luminosity in the AGN population, but we caution on the importance of selection effects inherent to such AGN-dominated emission-line galaxies in driving such a correlation. We highlight the MIR-radio plane as a useful tool in comparative studies of SF and nuclear activity in AGN.
In the last several years considerable efforts have been devoted to developing Bose-Einstein Condensate (BEC)-based devices for applications such as fundamental research, precision measurements and integrated atom optics. Such devices capable of complex functionality can be designed from simpler building blocks as is done in microelectronics. One of the most important components of microelectronics is a transistor. We demonstrate that Bose-Einstein condensate in a three well potential structure where the tunneling of atoms between two wells is controlled by the population in the third, shows behavior similar to that of an electronic field effect transistor. Namely, it exhibits switching and both absolute and differential gain. The role of quantum fluctuations is analyzed, estimates of switching time and parameters for the potential are presented.
The complete sets of analytic solutions of the geodesic equation in Taub--NUT--(anti-)de Sitter, Kerr--(anti-)de Sitter and also in general Plebanski--Demianski space--times without acceleration are presented. The solutions are given in terms of the Kleinian sigma functions.
We present preliminary results of the CIDA Equatorial Variability Survey (CEVS), looking for quasar (hereafter QSO) candidates near the Galactic plane. The CEVS contains photometric data from extended and adjacent regions of the Milky Way disk ($\sim$ 500 sq. deg.). In this work 2.5 square degrees with moderately high temporal sampling in the CEVS were analyzed. The selection of QSO candidates was based on the study of intrinsic optical photometric variability of 14,719 light curves. We studied samples defined by cuts in the variability index (Vindex $>$ 66.5), periodicity index (Q $>$ 2), and the distribution of these sources in the plane (AT , ${\gamma}$), using a slight modification of the first-order of the structure function for the temporal sampling of the survey. Finally, 288 sources were selected as QSO candidates. The results shown in this work are a first attempt to develop a robust method to detect QSO towards the Galactic plane in the era of massive surveys such as VISTA and Gaia.
An infinite system of nonlocal, individually confining solitons is considered as a model of high-density nuclear matter. The soliton-lattice problem is discussed in the Wigner-Seitz approximation. The cell size is varied to study the density dependence of physical quantities of interest. A transition to a system where quarks can migrate between solitons is found. We argue that this signals quark deconfinement. The model is applied to the calculation of selected in-medium properties.
[Abridged] In our previous work on Ark 120, we found that its 2014 X-ray spectrum is dominated by Comptonisation, while the relativistic reflection emission only originates at tens of $R_{\rm g}$ from the SMBH. As a result, we could not constrain the SMBH spin from disc reflection alone. Our aim is to determine its SMBH spin from an alternative technique based on the global energetics of the disc-corona system. The spectral analysis uses simultaneous XMM-Newton (OM and pn) and NuSTAR observations on 2014 March 22 and 2013 February 18. We applied the optxconv model (based on optxagnf) to self consistently reproduce the emission from the inner corona (warm and hot thermal Comptonisation) and the outer disc (colour temperature corrected black body), taking into account both the disc inclination angle and relativistic effects. We modelled the mild relativistic reflection of the incident Comptonisation components using the xilconv model. We infer a SMBH spin of 0.83$^{+0.05}_{-0.03}$, adopting the SMBH reverberation mass of 1.50$\times$10$^{8}$ M$_{\odot}$. In addition, we find that the coronal radius decreases with increasing flux (by about a factor of two), from 85$^{+13}_{-10}$ $R_{\rm g}$ in 2013 to 14$\pm$3 $R_{\rm g}$ in 2014. This is the first time that such a constraint is obtained for a SMBH spin from this technique, thanks to the bare properties of Ark 120, its well determined SMBH mass, and the presence of a mild relativistic reflection component in 2014 which allows us to constrain the disc inclination angle. We caution that these results depend on the detailed disc-corona structure, which is not yet fully established. However, the realistic parameter values found suggest that this is a promising method to determine spin in moderate accretion rate AGN.
A many-body expansion for the computation of the charge form factor in the center-of-mass system is proposed. For convergence testing purposes, we apply our formalism to the case of the harmonic oscillator shell model, where an exact solution exists. We also work out the details of the calculation involving realistic nuclear wave functions. Results obtained for the Argonne $v$18 two-nucleon and Urbana-IX three-nucleon interactions are reported. No corrections due to the meson-exchange charge density are taken into account.
We study the connectedness of the non-subklt locus over the spectrum of a formal power series ring. In dimension 3, we prove the existence and normality of the smallest lc centre, and apply it to the ACC for minimal log discrepancies greater than 1 on non-singular 3-folds.
We study $bt\bar t$ production via subprocesses initiated by $b$-quarks at the Large Hadron Collider. Both QCD and electroweak interactions are included in the elementary scattering amplitudes for $bg\to b t\bar t$. Since the additional jet in the final state (arising from the bottom quark) is in most cases at very low transverse momentum and very high pseudorapidity, it tends to escape detection. Therefore, such a process can act as a background to double-top as well as to single-top channels exploited in top quark phenomenology at present and future hadron colliders. Furthermore, if the additional $b$-jet can be tagged then $bt\bar t$ samples can be exploited in constraining possible effects of New Physics. The relevance of this reaction in such contexts is discussed and various total and differential rates of phenomenological interest are given
We study the spectroscopic properties and environments of red spiral galaxies found by the Galaxy Zoo project. By carefully selecting face-on, disk dominated spirals we construct a sample of truly passive disks (not dust reddened, nor dominated by old stellar populations in a bulge). As such, our red spirals represent an interesting set of possible transition objects between normal blue spirals and red early types. We use SDSS data to investigate the physical processes which could have turned these objects red without disturbing their morphology. Red spirals prefer intermediate density regimes, however there are no obvious correlations between red spiral properties and environment - environment alone is not sufficient to determine if a spiral will become red. Red spirals are a small fraction of spirals at low masses, but are a significant fraction at large stellar masses - massive galaxies are red independent of morphology. We confirm that red spirals have older stellar popns and less recent star formation than the main spiral population. While the presence of spiral arms suggests that major star formation cannot have ceased long ago, we show that these are not recent post-starbursts, so star formation must have ceased gradually. Intriguingly, red spirals are ~4 times more likely than normal spirals to host optically identified Seyfert or LINER, with most of the difference coming from LINERs. We find a curiously large bar fraction in the red spirals suggesting that the cessation of star formation and bar instabilities are strongly correlated. We conclude by discussing the possible origins. We suggest they may represent the very oldest spiral galaxies which have already used up their reserves of gas - probably aided by strangulation, and perhaps bar instabilities moving material around in the disk.
We generalise the theory of mean-field galactic dynamos by allowing for temporal non-locality in the mean electromotive force (emf). This arises in random flows due to a finite response time of the mean emf to changes in the mean magnetic field, and leads to the telegraph equation for the mean field. The resulting dynamo model also includes the nonlinear dynamo effects arising from magnetic helicity balance. Within this framework, coherent large-scale magnetic spiral arms superimposed on the dominant axially symmetric magnetic structure are considered. A non-axisymmetric forcing of the mean-field dynamo by a spiral pattern (either stationary or transient) is invoked, with the aim of explaining the phenomenon of magnetic arms. For a stationary dynamo forcing by a rigidly rotating material spiral, we find corotating non-axisymmetric magnetic modes enslaved to the axisymmetric modes and strongly peaked around the corotation radius. For a forcing by transient material arms wound up by the galactic differential rotation, the magnetic spiral is able to adjust to the winding so that it resembles the material spiral at all times. There are profound effects associated with the temporal non-locality, i.e. finite `dynamo relaxation time'. For the case of a rigidly rotating spiral, a finite relaxation time causes each magnetic arm to mostly lag the corresponding material arm with respect to the rotation. For a transient material spiral that winds up, the finite dynamo relaxation time leads to a large, negative (in the sense of the rotation) phase shift between the magnetic and material arms, similar to that observed in NGC 6946 and other galaxies. We confirm that sufficiently strong random seed fields can lead to global reversals of the regular field along the radius whose long-term survival depends on specific features of a given galaxy.
We consider the inverse problem to determine a smooth compact Riemannian manifold with boundary $(M, g)$ from a restriction $\Lambda_{\Src, \Rec}$ of the Dirichlet-to-Neumann operator for the wave equation on the manifold. Here $\Src$ and $\Rec$ are open sets in $\p M$ and the restriction $\Lambda_{\Src, \Rec}$ corresponds to the case where the Dirichlet data is supported on $\R_+\times \Src$ and the Neumann data is measured on $\R_+\times \Rec$. In the novel case where $\bar \Src \cap \bar \Rec = \emptyset$, we show that $\Lambda_{\Src, \Rec}$ determines the manifold $(M,g)$ uniquely, assuming that the wave equation is exactly controllable from the set of sources $\Src$. Moreover, we show that the exact controllability can be replaced by the Hassell-Tao condition for eigenvalues and eigenfunctions, that is, \lambda_j \le C \norm{\p_\nu \phi_j}_{L^2(\Src)}^2, \quad j =1, 2, ..., where $\lambda_j$ are the Dirichlet eigenvalues and $(\phi_j)_{j=1}^\infty$ is an orthonormal basis of the corresponding eigenfunctions.
The shape of large on-lattice Eden clusters grown from a single seed is ruled by the underlying lattice anisotropy. This is reflected on the linear growth with time of the interface width ($w\sim t$), in contrast with the KPZ universality class ($w\sim t^{1/3}$) observed when the Eden model is grown on flat substrates. We propose an extended Eden model, in which the growth probability has a power law dependence with the number of occupied nearest neighbors. Large scale simulations ($N\gtrsim 4\times 10^9$ particles) were used to determine the time evolution of $w$. We found that a suitable choice of the power exponent removes the lattice-induced cluster anisotropy and provides a growth exponent in very good agreement with the KPZ universality class. Also, the present model corroborates the results found in off-lattice simulations, in which the center of mass fluctuations are considered in the interface scaling analysis.