Miracle-dz/UniFAR-FTUs huggingface dataset:
The stellar populations of bright coma cluster galaxies

In this paper we study the stellar populations of 356 bright, M r < -19, Coma cluster members located in a 2° field centred on the cluster core using Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) spectroscopy. We find ∼31 per cent of the sample have significant emission in Hβ, [O m]5007, Hα or [N II]6585, due to star formation or active galactic nuclei (AGN)/LINER activity. The remaining portion of the sample we describe as passive or quiescent. Using line-ratio diagnostics, we find the fraction of galaxies displaying AGN/LINER type emission increases with increasing galaxy luminosity while the star-forming fraction decreases. For the quiescent galaxies we find strong correlations between absorption-line index strength and velocity dispersion (σ) for CN2, C4668, Mgb and Hβ. Employing a planar analysis technique that factors out index correlations with σ, we find significant cluster-centric radial gradients in Hβ, Mgb and C4668 for the passive galaxies. We use state-of-the-art stellar population models and the measured absorption-line indices to infer the single-stellar-population-equivalent (SSP-equivalent) age and [Fe/H] for each galaxy, as well as their abundance patterns in terms of [Mg/Fe], [C/Fe], [N/Fe] and [Ca/Fe]. For the passive galaxy subsample we find strong evidence for 'archaeological downsizing', with age α σ 0.90±0.06 . This trend is shown to be robust against variations in sample selection criteria (morphologically early-type versus spectroscopically quiescent), emission-line detection thresholds, index velocity broadening corrections and the specific SSP model employed. Weaker positive correlations are obtained between σ and all other measured stellar population parameters. We recover significant cluster-centric radial stellar population gradients for the passive sample in SSP-equivalent age, [Mg/Fe], [C/Fe] and [N/Fe]. These trends are in the sense that, at fixed velocity dispersion, passive galaxies on the outskirts of the cluster are 24 ± 9 per cent younger with lower [Mg/Fe] and [N/Fe] but higher [C/Fe] than those in the cluster core. We find no significant increase in cluster-centric radial stellar population gradients when fitting to a passive galaxy subset selected to cover the cluster core and south-west region, which contains the NGC 4839 subgroup. Thus, we conclude that the NGC 4839 infall region is not unique, at least in terms of the stellar populations of bright galaxies. We speculate that the more pronounced cluster-centric radial gradients seen by other recent studies may be attributed to the luminosity range spanned by their samples, rather than to limited azimuthal coverage of the cluster. Finally, for our passive sample we have found an age-metallicity anti-correlation which cannot be accounted for by correlated errors.
CHEMICAL EVOLUTION OF RED MSX SOURCES IN THE SOUTHERN SKY

Red Midcourse Space Experiment (MSX) Sources (RMSs) are regarded as excellent candidates of massive star-forming regions. In order to characterize the chemical properties of massive star formation, we made a systematic study of 87 RMSs in the southern sky, using archival data taken from the Atacama Pathfinder Experiment Telescope Large Area Survey of the Galaxy (ATLASGAL), the Australia Telescope Compact Array, and the Millimetre Astronomy Legacy Team Survey at 90 GHz (MALT90). According to previous multiwavelength observations, our sample could be divided into two groups: massive young stellar objects and H ii regions. Combined with the MALT90 data, we calculated the column densities of N2H+, C2H, HC3N, and HNC and found that they are not much different from previous studies made in other massive star-forming regions. However, their abundances are relatively low compared to infrared dark clouds (IRDCs). The abundances of N2H+ and HNC in our sample are at least 1 mag lower than those found in IRDCs, indicating chemical depletions in the relatively hot gas. Besides, the fractional abundances of N2H+, C2H, and HC3N seem to decrease as a function of their Lyman continuum fluxes (NL), indicating that these molecules could be destroyed by UV photons when H ii regions have formed inside. We also find that the C2H abundance decreases faster than HC3N with respect to NL. The abundance of HNC has a tight correlation with that of N2H+, indicating that it may be also preferentially formed in cold gas. We regard our RMSs as being in a relatively late evolutionary stage of massive star formation.
The brighter-fatter effect and pixel correlations in CCD sensors

We present evidence that spots imaged using astronomical CCDs do not exactly scale with flux: bright spots tend to be broader than faint ones, using the same illumination pattern. We measure that the linear size of spots or stars, of typical size 3 to 4 pixels FWHM, increase linearly with their flux by up to 2 % over the full CCD dynamic range. This brighter-fatter effect affects both deep-depleted and thinned CCD sensors. We propose that this effect is a direct consequence of the distortions of the drift electric field sourced by charges accumulated within the CCD during the exposure and experienced by forthcoming light-induced charges in the same exposure. The pixel boundaries then become slightly dynamical: overfilled pixels become increasingly smaller than their neighbors, so that bright star sizes, measured in number of pixels, appear larger than those of faint stars. This interpretation of the brighter-fatter effect implies that pixels in flat-fields should exhibit statistical correlations, sourced by Poisson fluctuations, that we indeed directly detect. We propose to use the measured correlations in flat-fields to derive how pixel boundaries shift under the influence of a given charge pattern, which allows us in turn to predict how star shapes evolve with flux. We show that, within the precision of our tests, we are able to quantitatively relate the correlations of flat-field pixels and the broadening of stars with flux. This physical model of the brighter-fatter effect also explains the commonly observed phenomenon that the spatial variance of CCD flat-fields increases less rapidly than their average.
Planets around stars in young nearby associations - Radial velocity searches: a feasibility study and first results

Context. Stars in young nearby associations are the only targets that allow giant planet searches in the near future, at all separations by coupling indirect techniques, such as radial velocity (RV) and deep imaging. These stars are first priority targets for the forthcoming planet imagers on eight- to ten-metre class telescopes. Young stars rotate more rapidly and are more active than their older counterparts. Both effects can limit the ability to detect planets using RV. Aims. We wish to explore the planet detection abilities of a representative sample of stars in close and young associations with RV data and to explore the complementarity between this technique and direct imaging. Methods. We observed 26 such targets with spectral types from A to K and ages from 8 to 300 Myr with HARPS. We computed the detection limits with two methods, in particular, a method we have recently developed that takes the frequency distribution of the RV variations into account. We also attempted to improve the detection limits in a few cases by correcting for the stellar activity. Results. Our A-type stars RV show high-frequency variations due to pulsations, while our F-K stars clearly show activity with more or less complex patterns. For F-K stars, the RV jitter and v sini rapidly decrease with star age. The data allow us to search for planets with periods typically ranging from 1 day to 100 days, and up to more than 500 days in a few cases. Within the present detection limits, no planet was found in our sample. For the bulk of our F-K stars, the detection limits fall to sub-Jupiter masses. We show that these limits can be significantly improved by correcting even partially for stellar activity, down to a few Neptune masses for the least active stars. The detection limits on A-type stars can be significantly improved, down to a few Jupiter-mass planets, provided an appropriate observing strategy. We finally show the tremendous potential of coupling RV and adaptive-optics deep imaging results. Conclusions. The RV technique allows the detection of planets lighter than Jupiter, reaching a few Neptune masses around young stars aged typically 30 Myr or more. Detection limits increase at younger ages, but (sub-)Jupiter mass planets are still detectable. In the next few years, using complementary techniques will allow a full exploration of the Jupiter-mass planets’ content of many of these stars.
Direct observational evidence for a large transient galaxy population in groups at 0.85 < z < 1

We introduce our survey of galaxy groups at 0.85 15 members. The dynamical mass estimates are in good agreement with the masses estimated from the X-ray luminosity, with most of the groups having 13 1010.1 M⊙. A few group galaxies inhabit the ‘blue cloud’ that dominates the surrounding field; instead, we find a large and possibly distinct population of galaxies with intermediate colours. The ‘green valley’ that exists at low redshift is instead well populated in these groups, containing ∼30 per cent of the galaxies. These do not appear to be exceptionally dusty galaxies, and about half show prominent Balmer absorption lines. Furthermore, their Hubble Space Telescope morphologies appear to be intermediate between those of red-sequence and blue-cloud galaxies of the same stellar mass. Unlike red-sequence galaxies, most of the green galaxies have a disc component, but one that is smaller and less structured than discs found in the blue cloud. We postulate that these are a transient population, migrating from the blue cloud to the red sequence, with a star formation rate that declines with an exponential time-scale 0.6 < τ < 2 Gyr. Such galaxies may not be exclusive to the group environment, as we find examples also amongst the non-members. However, their prominence among the group galaxy population, and the marked lack of blue, star-forming galaxies, provides evidence that the group environment either directly reduces star formation in member galaxies or at least prevents its rejuvenation during the normal cycle of galaxy evolution.
Electric dipole moments of charged leptons at one loop in the presence of massive neutrinos

Violation of CP invariance is a quite relevant phenomenon that is found in the Standard Model, though in small amounts. This has been an incentive to look for high-energy descriptions in which CP violation is increased, thus enhancing effects that are suppressed in the Standard Model, such as the electric dipole moments of elementary particles. In the present investigation, we point out that charged currents in which axial couplings are different from vector couplings are able to produce one-loop contributions to electric dipole moments of charged leptons if neutrinos are massive and if these currents violate CP. We develop our discussion around charged currents involving heavy neutrinos and a W′ gauge boson coupling to Standard Model charged leptons. Using the most stringent bound on the electron electric dipole moment, provided by the ACME Collaboration, we determine that the upper bound on the difference between axial and vector currents lies within ∼10-10 and ∼10-7 for heavy-neutrino masses between 0.5 TeV and 6 TeV and if the W′ mass is within 0.45 TeV–7 TeV. This possibility is analyzed altogether with the anomalous magnetic moments of charged leptons, among which we estimate, for the τ lepton, an anomalous magnetic moment contribution between ∼10-8 and ∼10-10 for neutrino masses ranging from 0.5 TeV to 6 TeV and a W′ mass between 0.45 TeV and 7 TeV. The general charged currents are also used to calculate the branching ratio for μ→eγ, which gets suppressed if the set of masses of heavy neutrinos is quasidegenerate. In a scenario of nondegenerate neutrino masses, we find that regions of neutrino and W′ masses in which the contributions to this flavor-changing branching ratio are lower than the current upper bound exist. We show that such regions can be widened if the W′ gauge boson mass is larger.
Master equation approach to computing RVB bond amplitudes

frustration (J2 = 0), the amplitudes are radially symmetric and fall off as 1/r 3 in the bond length. As the frustration increases, there are precursor signs of columnar or plaquette VBS order: the bonds preferentially align along the axes of the square lattice and weight accrues in the nearest-neighbour bond amplitudes. The Marshall sign rule holds over a large range of couplings, J2/J1 . 0.418. It fails when the r = (2,1) bond amplitude first goes negative, a point also marked by a cusp in the ground state energy. A nonrigourous extrapolation of the staggered magnetic moment (through this point of nonanalyticity) shows it vanishing continuously at a critical value J2/J1 ≈ 0.447. This may be preempted by a first-order transition to a state of broken translational symmetry.
GALEX FAR-ULTRAVIOLET COLOR SELECTION OF UV-BRIGHT HIGH-REDSHIFT QUASARS

We study the small population of high-redshift (zem>2.7) quasars detected by the Galaxy Evolution Explorer(GALEX), whose far-UV emission is not extinguished by intervening H i Lyman limit systems. These quasars are of particular importance to detect intergalactic He ii absorption along their sight lines. We correlate almost all verified zem>2.7 quasars to the GALEX GR4 source catalog covering ∼ 25,000 deg2, yielding 304 sources detected at signal-to-noise ratio (S/N) >3. However, ∼50% of these are only detected in the GALEX NUV band, signaling the truncation of the FUV flux by low-redshift optically thick Lyman limit systems. We exploit the GALEX UV color mFUV − mNUV to cull the most promising targets for follow-up studies, with blue (red) GALEX colors indicating transparent (opaque) sight lines. Extensive Monte Carlo simulations indicate an He ii detection rate of ∼60% for quasars with mFUV − mNUV ≲ 1 at zem ≲ 3.5, a ∼50% increase over GALEX searches that do not include color information. We regard 52 quasars detected at S/N >3 to be most promising for Hubble Space Telescope follow-up, with an additional 114 quasars if we consider S/N >2 detections in the FUV. Combining the statistical properties of H i absorbers with the Sloan Digital Sky Survey (SDSS) quasar luminosity function, we predict a large all-sky population of ∼200 quasars with zem>2.7 and i ≲ 19 that should be detectable at the He ii edge at m304 < 21. However, SDSS provides just half of the NUV-bright quasars that should have been detected by SDSS and GALEX. With mock quasar photometry we revise the SDSS quasar selection function, finding that SDSS systematically misses quasars with blue u − g ≲ 2 colors at 3 ≲ zem ≲ 3.5 due to overlap with the stellar locus in color space. Our color-dependent SDSS selection function naturally explains the inhomogeneous u − g color distribution of SDSS DR7 quasars as a function of redshift and the color difference between color-selected and radio-selected SDSS quasars. Moreover, it yields excellent agreement between the observed and the predicted number of GALEX UV-bright SDSS quasars. We confirm our previous claims that SDSS preferentially selects 3 ≲ zem ≲ 3.5 quasars with intervening H i Lyman limit systems. Our results imply that broadband optical color surveys for 3 ≲ zem ≲ 3.5 quasars have likely underestimated their space density by selecting intergalactic medium sight lines with an excess of strong H i absorbers.
Improvement of an optical image by the measurement reduction technique at parametric multiplexing

In the process of parametric optical image amplification, images are formed at new frequencies in addition to the amplified original image. We show that parametric multiplexing of optical images can be used to produce an image with improved quality. As an example, we study the parametric amplification of an optical image at low-frequency pumping in which multiplexed optical images turn out to be quantum-correlated. Additional improvement is made possible by using the information about the object that is available to the researcher, in particular, about sparsity of its image. To take the available information into account, we apply the measurement reduction technique.
MAGNETIC FIELDS AND THE OUTER ROTATION CURVE OF M31

Recent observations of the rotation curve of M31 show a rise of the outer part that cannot be understood in terms of standard dark matter models or perturbations of the galactic disk by M31's satellites. Here, we propose an explanation of this dynamical feature based on the influence of the magnetic field within the thin disk. We have considered standard mass models for the luminous mass distribution, a Navarro–Frenk–White model to describe the dark halo, and we have added up the contribution to the rotation curve of a magnetic field in the disk, which is described by an axisymmetric pattern. Our conclusion is that a significant improvement of the fit in the outer part is obtained when magnetic effects are considered. The best-fit solution requires an amplitude of ∼4 μG with a weak radial dependence between 10 and 38 kpc.
Simulation of the relativistic electron dynamics and acceleration in a linearly-chirped laser pulse

Theoretical investigations are presented, and their results are discussed, of the laser acceleration of a single electron by a chirped pulse. Fields of the pulse are modeled by simple plane-wave oscillations and a $\cos^2$ envelope. The dynamics emerge from analytic and numerical solutions to the relativistic Lorentz-Newton equations of motion of the electron in the fields of the pulse. All simulations have been carried out by independent Mathematica and Python codes, with identical results. Configurations of acceleration from a position of rest as well as from injection, axially and sideways, at initial relativistic speeds are studied.
Research on The Impact of Energy-Saving and Emission Reduction Policy on The Difference of Green Patent Holdings of Enterprise

The article takes the 13th Five-Year Plan for energy-saving and emission reduction as an example, study the impact of this energy-saving and emission reduction policy on the company's green patent holdings. Based on the data of listed companies of heavy polluting enterprises in Shanghai and Shenzhen from 2014 to 2019, we selected 100 companies in two control areas and non-two control areas, using the DID method to compare the implementation of the policy to testify whether the proportion of green patent authorizations in the two areas can increase the test of policy's inducing effect on enterprises' green innovation. The study found that the policy has a negative impact on the company's green patent holdings after the implementation of the policy in the pilot area, in other words, the regional company's green patent holdings after the implementation of the policy has show a downward trend. Therefore, the policy exists the timeliness and the patent can not be authorization in a short time. Enterprises need to pay for extra pollution discharge due to the implementation of the policy, which can decrease the R&D investment of company and the number of green patents will be decline.
Strong gravitational lensing across a dilaton anti-de Sitter black hole

In this work we investigate the gravitational lensing effect in the strong field region around dilaton black holes in an anti-de Sitter space. We also analyze the dependence of the radius of the photon sphere and deflection angle on dilaton coupling and the cosmological constant in this black hole spacetime. Finally the values of minimum impact parameter, the separation between the first and the other images, as well as the ratio between the flux of the first image and the flux coming from all the other images are determined to characterize some possible distinct signatures of such black holes.
Stellar Core Collapse in Full General Relativity with Microphysics Formulation and Spherical Collapse Test

One of the longstanding issues in numerical relativity is to enable a simulation taking account of microphysical processes (e.g., weak interactions and neutrino cooling). We develop an approximate and explicit scheme in the fully general relativistic framework as a first implementation of the microphysics toward a more realistic and sophisticated modeling. In this paper, we describe in detail a method for implementation of a realistic equation of state, the electron capture and the neutrino cooling in a multidimensional, fully general relativistic code. The procedure is based on the so-called neutrino leakage scheme. To check the validity of the code, we perform a two dimensional (2D) simulation of spherical stellar core collapse. Until the convective activities set in, our results approximately agree, or at least are consistent, with those in the previous so-called state-of-the-art simulations. In particular, the radial profiles of thermodynamical quantities and the time evolution of the neutrino luminosities agree quantitatively. The convection is driven by negative gradients of the entropy per baryon and the electron fraction as in the previous 2D Newtonian simulations. We clarify which gradient is more responsible for the convection. Gravitational waves from the convection are also calculated. We find that the characteristic frequencies of the gravitational-wave spectra are distributed for higher frequencies than those in Newtonian simulations due to the general relativistic effects. Subject Index: 421, 423
Design of a CMOS Parametric Frequency Divider with 2.4-GHz Output Frequency for RF Systems-on-a-Chip

This paper presents a CMOS 2:1 differential parametric frequency divider (PFD) design with an output frequency of 2.4 GHz and an input voltage range of 450~890 mV at 4.8 GHz. The topology is suitable for integration into RF Systems-on-a-Chip (SoCs), and has been constructed for sub-6 GHz applications. A design and optimization methodology for this on-chip PFD is also described in this paper. The simulation results show a performance improvement of the proposed differential PFD compared to a single-ended PFD designed for the same output frequency in the same 65nm CMOS technology.
Stability of BEC galactic dark matter halos

In this paper we show that spherically symmetric BEC dark matter halos, with the sin r/r density profile, that accurately fit galactic rotation curves and represent a potential solution to the cusp-core problem are unstable. We do this by introducing back the density profiles into the fully time-dependent Gross-Pitaevskii-Poisson system of equations. Using numerical methods to track the evolution of the system, we found that these galactic halos lose mass at an approximate rate of half of its mass in a time scale of dozens of Myr. We consider this time scale is enough as to consider these halos are unstable and unlikely to be formed. We provide some arguments to show that this behavior is general and discuss some other drawbacks of the model that restrict its viability.