Abstract visibility
Abstract text size

Papers for Monday, Jan 03 2022

Papers with local authors

L. G. Bouma, J. L. Curtis, K. Masuda, L. A. Hillenbrand, G. Stefansson, H. Isaacson, N. Narita, A. Fukui, M. Ikoma, M. Tamura, A. L. Kraus, E. Furlan, C. L. Gnilka, K. V. Lester, S. B. Howell

AJ accepted, Table 3 available upon request

0 votes
Paper 1 — arXiv:2112.14776
0 votes
Paper 1 — arXiv:2112.14776

Kepler 1627A is a G8V star previously known to host a 3.8 Earth-radius planet on a 7.2 day orbit. The star was observed by the Kepler space telescope because it is nearby (d=329 pc) and it resembles the Sun. Here we show using Gaia kinematics, TESS stellar rotation periods, and spectroscopic lithium abundances that Kepler 1627 is a member of the 38 $\pm$ 6 Myr old $\delta$ Lyr cluster. To our knowledge, this makes Kepler 1627Ab the youngest planet with a precise age yet found by the prime Kepler mission. The Kepler photometry shows two peculiarities: the average transit profile is asymmetric, and the individual transit times might be correlated with the local light curve slope. We discuss possible explanations for each anomaly. More importantly, the $\delta$ Lyr cluster is one of about 10$^3$ coeval groups whose properties have been clarified by Gaia. Many other exoplanet hosts are candidate members of these clusters; these memberships can be verified with the trifecta of Gaia, TESS, and ground-based spectroscopy.

M. L. Graham, C. Fremling, D. A. Perley, R. Biswas, C. A. Phillips, J. Sollerman, P. E. Nugent, S. Nance, S. Dhawan, J. Nordin, A. Goobar, A. Miller, J. D. Neill, X. J. Hall, M. J. Hankins, D. A. Duev, M. M. Kasliwal, M. Rigault, E. C. Bellm, D. Hale, P. Mróz, S. R. Kulkarni

14 pages, 4 tables, 7 figures, accepted to MNRAS

0 votes
Paper 6 — arXiv:2112.14819
0 votes
Paper 6 — arXiv:2112.14819

Supernova (SN) siblings -- two or more SNe in the same parent galaxy -- are useful tools for exploring progenitor stellar populations as well as properties of the host galaxies such as distance, star formation rate, dust extinction, and metallicity. Since the average SN rate for a Milky Way-type galaxy is just one per century, a large imaging survey is required to discover an appreciable sample of SN siblings. From the wide-field Zwicky Transient Facility (ZTF) Bright Transient Survey (BTS; which aims for spectroscopic completeness for all transients which peak brighter than $r{<}$18.5 mag) we present 10 SN siblings in 5 parent galaxies. For each of these families we analyze the SN's location within the host and its underlying stellar population, finding agreement with expectations that SNe from more massive progenitors are found nearer to their host core and in regions of more active star formation. We also present an analysis of the relative rates of core collapse and thermonuclear SN siblings, finding a significantly lower ratio than past SN sibling samples due to the unbiased nature of the ZTF.

All other papers

Alexander J. Dittmann

12 pages, 12 figures, submitted to MNRAS. Comments welcome

We present an analytic and fully relativistic framework for studying the self-intersection of tidal disruption event (TDE) streams, restricting ourselves to the Schwarzschild spacetime. By taking advantage of the closed-form solution to the geodesic equations in the Schwarzschild metric, we calculate properties of the self-intersection without numerically evaluating the geodesic equations or making any post-Newtonian approximations. Our analytic treatment also facilitates geometric definitions of the orbital semi-major axis and eccentricity, as opposed to Newtonian formulas which lead to unphysical results for highly-relativistic orbits. Combined with assumptions about energy dissipation during the self-intersection shock, our framework enables the calculation of quantities such as the fraction of material unbound during the self-intersection shock, and the characteristic semi-major axes and eccentricities of the material which remains in orbit after the collision. As an example, we calculate grids of post-intersection properties in stellar and supermassive black hole (SMBH) masses for disruptions of main sequence stars, identifying regions where no material is ejected during self intersection (e.g. SMBH mass $\lesssim 5\times10^6\, {\rm M_\odot}$ for $1\,{\rm M_\odot}$ stars disrupted at the tidal radius), potentially explaining the TDEs observed by SGR/eROSITA which are visible in X-rays but not optical wavelengths. We also identify parameters for which the post-intersection accretion flow has low eccentricity ($e\lesssim0.6$), and find that the luminosity generated by self-intersection shocks only agrees with observed trends in the relationship between light curve decay timescales and peak luminosities over a narrow range of SMBH masses.

Our understanding of reionization has advanced considerably over the past decade, with several results now demonstrating that the IGM transitioned from substantially neutral at $z=7$ to largely reionized at $z=6$. However, little remains known about the sizes of ionized bubbles at $z\gtrsim7$ as well as the galaxy overdensities which drive their growth. Fortunately, rest-UV spectroscopic observations offer a pathway towards characterizing these ionized bubbles thanks to the resonant nature of Lyman-alpha photons. In a previous work, we presented Ly$\alpha$ detections from three closely-separated Lyman-break galaxies at $z\simeq6.8$, suggesting the presence of a large ($R>1$ physical Mpc) ionized bubble in the 1.5 deg$^2$ COSMOS field. Here, we present new deep Ly$\alpha$ spectra of ten UV-bright ($\mathrm{M}_{\mathrm{UV}}^{} \leq -20.4$) $z\simeq6.6-6.9$ galaxies in the surrounding area, enabling us to better characterize this potential ionized bubble. We confidently detect (S/N$>$7) Ly$\alpha$ emission at $z=6.701-6.882$ in nine of ten observed galaxies, revealing that the large-scale volume spanned by these sources (characteristic radius $R = 3.2$ physical Mpc) traces a strong galaxy overdensity ($N/\langle N\rangle \gtrsim 3$). Our data additionally confirm that the Ly$\alpha$ emission of UV-bright galaxies in this volume is significantly enhanced, with 40% (4/10) showing strong Ly$\alpha$ emission (equivalent width$>$25 $\mathrm{\mathring{A}}$) compared to the 8$-$9% found on average at $z\sim7$. The median Ly$\alpha$ equivalent width of our observed galaxies is also $\approx$2$\times$ that typical at $z\sim7$, consistent with expectations if a very large ($R\sim3$ physical Mpc) ionized bubble is allowing the Ly$\alpha$ photons to cosmologically redshift far into the damping wing before encountering HI.

A major uncertainty in understanding the transport and feedback of cosmic-rays (CRs) within and beyond our Galaxy lies in the unknown CR scattering rates, which are primarily determined by wave-particle interaction at microscopic gyro-resonant scales. The source of the waves for the bulk CR population is believed to be self-driven by the CR streaming instability (CRSI), resulting from the streaming of CRs downward a CR pressure gradient. While a balance between driving by the CRSI and wave damping is expected to determine wave amplitudes and hence the CR scattering rates, the problem involves significant scale separation with substantial ambiguities based on quasi-linear theory (QLT). Here we propose a novel "streaming box" framework to study the CRSI with an imposed CR pressure gradient, enabling first-principle measurement of the CR scattering rates as a function of environmental parameters. By employing the magnetohydrodynamic-particle-in-cell (MHD-PIC) method with ion-neutral damping, we conduct a series of simulations with different resolutions and CR pressure gradients and precisely measure the resulting CR scattering rates in steady state. The measured rates show scalings consistent with QLT, but with a normalization smaller by a factor of several than typical estimates based on single-fluid treatment of CRs. A momentum-by-momentum treatment provides better estimates when integrated over momentum, but is also subject substantial deviations especially at small momentum. Our framework thus opens up the path towards providing comprehensive subgrid physics for macroscopic studies of CR transport and feedback in broad astrophysical contexts.

C.A. Bertulani, R.V. Lobato

10 pages, 4 figures, contribution to the XLIV Brazilian Workshop on Nuclear Physics to be published by the IOP

Neutron tunneling in neutron star crusts can release enormous amounts of energy on a short timescale. We have clarified aspects of this process occurring in the outer crust regions of neutron stars when oscillations or cataclysmic events changes the crustal ambient density. We report a time-dependent Hartree-Fock-Bogoliubov model to determine the rate of neutron diffusion and conclude that a large amount of energy, in the range of 10^40 - 10^44 erg, can be released rapidly. We suggest that this mechanism may be the source of hitherto unknown phenomena such as the Fast Radio Bursts (FRBS).

B. Debski

Submitted to the Monthly Notices of the Royal Astronomical Society

This work studies the significance of the lightcurve intrinsic variability in the numerical modeling of contact binaries. Using synthetic light curves we are showing that the starspot-based intrinsic variability increases the apparent mass ratio by $\Delta q=5$%. For systems with orbital period $P>0.3 d$ the effect of intrinsic variability averaged over long time cancels each other out with the Kepler Mission-like phase smearing. Further, we analyse 47 totally eclipsing Kepler Mission contact binaries. We found a sharp cutoff of the intrinsic variability at P = 0.45 d. With the light curve numerical modeling and observational relations we derive physical parameters of the 47 systems. At least 53% of binaries have a possible third companion. 21 binaries show the O`Connell effect in the averaged phase curve. 19 of them have a primary maximum lower than the secondary, suggesting a stationary dark region on the trailing side. Using the P = 0.45 d cutoff we propose a new approach on the Period-Color relation. The only parameter correlating with the magnitude of the intrinsic variability is the apparent effective temperature ratio. We conclude that instead of describing the system parameters, the A/W-subtype division should be applicable only to the lightcurves, as a tentative phenomenon.

A.G. Kuranov, K.A. Postnov, L.R. Yungelson

32 pages, 15 figures

Employing hybrid population synthesis, a model of the population of ultraluminous X-ray sources (ULX) in the binary systems with a black hole (BH) accretors is computed. It is compared to the model of the population of ULX with magnetized neutron stars (NS) that can be observed as pulsating ULX (Kuranov et al. 2020). A model of formation of BH is considered, in which their mass is determined by the mass of stellar CO core immediately before the collapse, as well as "delayed" and "rapid" collapse models (Fryer et al. 2012). Possible transiency of ULX due to accretion disks instability is taken into account The parameters and evolution of ULX are computed for the galaxies with constant star formation rate (SFR) and for the ones formed by an instantaneous star formation burst. The maximum number of ULX with BH ($\sim 10$) is reached in the galaxies with stationary $ SFR=10$\msun/yr in $\sim 1$ Gyr after beginning of star formation. ULX which are observed after the end of star formation, are binaries, in which BH and/or NS formed before the completion of star formation, while long-living donors with the mass $\sim$\msun\ continue RLOF or even fill their Roche lobes later. In several Gyr after completion of star formation the number of ULX in the galaxies with mass $M_G=10^{10}$\,\msun\ becomes less than 1 per 10 galaxies, most of them are ULX with NS. In ULX with NS, regardless of the adopted SFR model, dominate persistent sources with the donor overflowing Roche lobe. The number of transient sources is by more than an order of magnitude lower. Wind-accreting ULX are by an order of magnitude more rare than the sources with accretion via RLOF.

This paper reports on the measurement of the large-scale anisotropy in the distribution of cosmic-ray arrival directions using the data collected by the air shower detector ARGO-YBJ from 2008 January to 2009 December,during the minimum of solar activity between cycles 23 and 24. In this period, more than 200 billion showers were recorded with energies between 1 and 30 TeV. The observed two-dimensional distribution of cosmic rays is characterized by two wide regions of excess and deficit, respectively, both of relative intensity 0.001 with respect to a uniform flux, superimposed on smaller size structures. The harmonic analysis shows that the large-scale cosmic-ray relative intensity as a function of R.A. can be described by the first and second terms of a Fouries series. The high event statistics allow the study of the energy dependence of the anistropy, showing that the amplitude increases with energy, with a maximum intensity at 10 TeV, and then decreases while the phase slowly shifts toward lower values of R.A. with increasing energy. The ARGO-YBJ data provide accurate observations over more than a decade of energy around this feature of the anisotropy spectrum.

Takatoshi Ko, Daichi Tsuna, Yuki Takei, Toshikazu Shigeyama

9 pages, 6 figures, 2 tables, To be submitted on January 7th

A significant fraction of supernovae show signatures of dense circumstellar material (CSM). While multiple scenarios for creating a dense CSM exist, mass eruption due to injection of energy at the base of the outer envelope is a likely possibility. We carry out radiation hydrodynamical simulations of eruptive mass loss from a typical red supergiant progenitor with initial mass of $15\ M_\odot$, for the first time focusing on the timescale of the injection as well as energy. We find that not only sufficient injection energy but also sufficient rate of energy injection per unit time, $L_{\rm{min}} \sim 8\times 10^{40}$ erg s$^{-1}$ in this particular model, is required for eruption of unbound CSM. This result suggests that the energy injection rate needs to be greater than the binding energy of the envelope divided by the dynamical timescale for the eruption. The density profile of the resulting CSM, whose shape was analytically and numerically predicted in the limit of instantaneous energy injection, similarly holds for a finite injection timescale. We discuss our findings in the framework of proposed mass outburst scenarios, specifically wave-driven outbursts and common envelope ejection.

Anna Nica, Benjamin D. Oppenheimer, Robert A. Crain, Ákos Bogdán, Jonathan J. Davies, William R. Forman, Ralph P. Kraft, John A. ZuHone

12 pages, 11 figures, 1 table. Submitted to MNRAS. Comments welcome

We investigate how the X-ray circumgalactic medium (CGM) of present-day galaxies depends on galaxy morphology and azimuthal angle using mock observations generated from the EAGLE cosmological hydrodynamic simulation. By creating mock stacks of {\it eROSITA}-observed galaxies oriented to be edge-on, we make several observationally-testable predictions for galaxies in the stellar mass range $M_\star=10^{10.7-11.2}\;$M$_{\odot}$. The soft X-ray CGM of disc galaxies is between 60 and 100\% brighter along the semi-major axis compared to the semi-minor axis, between 10-30 kpc. This azimuthal dependence is a consequence of the hot ($T>10^6$ K) CGM being non-spherical: specifically it is flattened along the minor axis such that denser and more luminous gas resides in the disc plane and co-rotates with the galaxy. Outflows enrich and heat the CGM preferentially perpendicular to the disc, but we do not find an observationally-detectable signature along the semi-minor axis. Spheroidal galaxies have hotter CGMs than disc galaxies related to spheroids residing at higher halos masses, which may be measurable through hardness ratios spanning the $0.2-1.5$ keV band. While spheroids appear to have brighter CGMs than discs for the selected fixed $M_\star$ bin, this owes to spheroids having higher stellar and halo masses within that $M_\star$ bin, and obscures the fact that both simulated populations have similar total CGM luminosities at the exact same $M_\star$. Discs have brighter emission inside 20 kpc and more steeply declining profiles with radius than spheroids. We predict that the {\it eROSITA} 4-year all-sky survey should detect many of the signatures we predict here, although targeted follow-up observations of highly inclined nearby discs after the survey may be necessary to observe some of our azimuthally-dependent predictions.

Qi-Yong Peng, Bi-Wen Bao, Fang-Wu Lu, Li Zhang

11 pages, 7 figures, ApJ accepted

Multi-band emission from radio to ultra-high energy gamma-rays in the Crab Nebula has been detected. To explain the observed results, non-thermal photon production \textbf{in} the Crab Nebula is carefully studied in a spatially dependent lepto-hadronic model. In our model, the dynamical evolution of the PWN is simulated in a spherically symmetric system. Both electrons and protons are accelerated at the termination shock. The relevant particle propagation equations as well as the photon evolving equation are simultaneously solved. For the Crab Nebula, our results reveal that the observed multi-band photon spectra can be well reproduced with reasonable model parameters. In particular, the photons with energy $\gtrsim 200$ TeV are mainly contributed by the hadronic component via proton-proton interaction. The contribution of the hadronic component depends on both proton spectral index $\alpha_{\rm p}$ and number density $n_{\rm H}$ of medium within the PWN. Besides, high energy neutrino fluxes are predicted with variable proton spectral indices. The predicted fluxes are not only far below the sensitivities of current neutrino observatories, but also beneath the atmospheric neutrino background with energy less than $\sim 40$ TeV. Moreover, the calculated radial profiles of surface brightness and spectral index are presented.

N. Magyar, T. Duckenfield, T. Van Doorsselaere, V. M. Nakariakov

Accepted to A&A

Context. Kink waves are routinely observed in coronal loops. Resonant absorption is a well-accepted mechanism that extracts energy from kink waves. Nonlinear kink waves are know to be affected by the Kelvin-Helmholtz instability. However, all previous numerical studies consider linearly polarized kink waves. Aims. We study the properties of circularly polarized kink waves on straight plasma cylinders, for both standing and propagating waves, and compare them to the properties of linearly polarized kink waves. Methods. We use the code MPI-AMRVAC to solve the full 3D Magnetohydrodynamic (MHD) equations for a straight magnetic cylinder, excited by both standing and propagating circularly polarized kink (m = 1) modes. Results. The damping due to resonant absorption is independent of the polarization state. The morphology or appearance of the induced resonant flow is different for the two polarizations, however, there are essentially no differences in the forward-modeled Doppler signals. For nonlinear oscillations, the growth rate of small scales is determined by the total energy of the oscillation rather than the perturbation amplitude. We discuss possible implications and seismological relevance.

By combining spectroscopic data from the LAMOST DR7, SDSS DR12, and corrected photometric data from the Gaia EDR3, we apply the Stellar Color Regression (SCR; Yuan et al. 2015a) method to recalibrate the SDSS Stripe 82 standard stars catalog of Ivezi\'c et al. (2007). With a total number of about 30,000 spectroscopically targeted stars, we have mapped out the relatively large and strongly correlated photometric zero-point errors present in the catalog, $\sim$2.5 per cent in the $u$ band and $\sim$ 1 per cent in the $griz$ bands. Our study also confirms some small but significant magnitude dependence errors in the $z$ band for some charge-coupled devices. Various tests show that we have achieved an internal precision of about 5 mmag in the $u$ band and about 2 mmag in the $griz$ bands, which is about 5 times better than previous results. We also apply the method to the latest version of the catalog (V4.2; Thanjavur et al. 2021), and find modest systematic calibration errors up to $\sim$ 1 per cent along the R.A. direction and smaller errors along the Dec. direction. The results demonstrate the power of the SCR method when combining spectroscopic data and Gaia photometry in breaking the 1 percent precision barrier of ground-based photometric surveys. Our work paves the way for the re-calibration of the whole SDSS photometric survey and has important implications for the calibration of future surveys. Future implementations and improvements of the SCR method under different situations are also discussed.

Yuandeng Shen, Xinping Zhou, Yadan Duan, Zehao Tang, Chengrui Zhou, Song Tan

55 pages, 17 figures, Accepted for publication in Solar Physics

QFP wave trains in the corona have been studied intensively in the past decade, thanks to the full-disk, high spatiotemporal resolution, and wide-temperature coverage observations taken by the SDO/AIA. In AIA observations, QFP wave trains are seen to consist of multiple coherent and concentric wavefronts emanating successively near the epicenter of the accompanying flares; they propagate outwardly either along or across coronal loops at fast-mode magnetosonic speeds from several hundred to more than 2000 km/s, and their periods are in the range of tens of seconds to several minutes. Based on the distinct different properties of QFP wave trains, they might be divided into two distinct categories including narrow and broad ones. For most QFP wave trains, some of their periods are similar to those of quasi-periodic pulsations (QPPs) in the accompanying flares, indicating that they are probably different manifestations of the same physical process. Currently, candidate generation mechanisms for QFP wave trains include two main categories: pulsed energy excitation mechanism in association with magnetic reconnection and dispersion evolution mechanism related to the dispersive evolution of impulsively generated broadband perturbations. In addition, the generation of some QFP wave trains might be driven by the leakage of three and five minute oscillations from the lower atmosphere. As one of the new discoveries of SDO, QFP wave trains provide a new tool for coronal seismology to probe the corona parameters, and they are also useful for diagnosing the generation of QPPs, flare processes including energy release and particle accelerations. This review aims to summarize the main observational and theoretical results of the spatially-resolved QFP wave trains in extreme ultraviolet observations, and states briefly a number of questions that deserve further investigations.

Shota Miyazaki, Daisuke Suzuki, Andrzej Udalski, Naoki Koshimoto, David P. Bennett, Nicholas J. Rattenbury, Takahiro Sumi, Fumio Abe, Richard K. Barry, Aparna Bhattacharya, Ian A. Bond, Akihiko Fukui, Hirosane Fujii, Yuki Hirao, Stela Silva, Yoshitaka Itow, Rintaro Kirikawa, Iona Kondo, Brandon Munford, Y. Matsubara, Sho Matsumoto, Yasushi Muraki, Arisa Okamura, Greg Olmschenk, Clément Ranc, Yuki K. Satoh, Taiga Toda, P. J. Tristram, Hibiki Yama, A. Yonehara, Radek Poleski, Przemek Mroz, Jan Skowron, Michal Szymanski, Igor Soszynski, Pawel Pietrukowicz, Syzmon Kozlowski, Krzysztof Ulaczyk, Lukasz Wyrzykowski

14 pages, 7 figures, Accepted for publication in the Astronomical Journal

We report the discovery of a sub-Jovian-mass planet, OGLE-2014-BLG-0319Lb. The characteristics of this planet will be added into a future extended statistical analysis of the Microlensing Observations in Astrophysics (MOA) collaboration. The planetary anomaly of the light curve is characterized by MOA and OGLE survey observations and results in three degenerate models with different planetary mass-ratios of $q=(10.3,6.6,4.5)\times10^{-4}$, respectively. We find that the last two models require unreasonably small lens-source relative proper motions of $\mu_{\rm rel}\sim1\;{\rm mas/yr}$. Considering Galactic prior probabilities, we rule out these two models from the final result. We conduct a Bayesian analysis to estimate physical properties of the lens system using a Galactic model and find that the lens system is composed of a $0.49^{+0.35}_{-0.27}\;M_{\rm Jup}$ sub-Jovian planet orbiting a $0.47^{+0.33}_{-0.25}\; M_{\odot}$ M-dwarf near the Galactic bulge. This analysis demonstrates that Galactic priors are useful to resolve this type of model degeneracy. This is important for estimating the mass ratio function statistically. However, this method would be unlikely successful in shorter timescale events, which are mostly due to low-mass objects, like brown dwarfs or free-floating planets. Therefore, careful treatment is needed for estimating the mass ratio function of the companions around such low-mass hosts which only the microlensing can probe.

Theodoros Papanikolaou, Charalampos Tzerefos, Spyros Basilakos, Emmanuel N. Saridakis

23 pages without appendices (30 pages total), 3 figures

The gravitational potential of a gas of initially randomly distributed primordial black holes (PBH) can induce a stochastic gravitational-wave background through second-order gravitational effects. This gravitational-wave background can be abundantly generated in a cosmic era of domination of ultralight primordial black holes, with masses $m_\mathrm{PBH}<10^{9}\mathrm{g}$, which evaporate before Big Bang Nucleosynthesis. Hence, the condition to avoid overproduction of gravitational waves at PBH evaporation time, can act as a novel method to extract constraints on cosmological models and gravitational theories. We consider $f(R)$ gravity as the underlying gravitational theory and we study its effect at the level of the gravitational potential of Poisson distributed primordial black holes. After the general analysis we focus on Starobinsky $R^2$ gravity model and we extract strong constraints on the involved mass parameter, denoted as $M$, as a function of the initial primordial black hole abundance, $\Omega_\mathrm{PBH,f}$ and the black hole mass, $m_\mathrm{PBH}$. In particular, one finds that in general $5\times 10^{-14}\lesssim\frac{M_\mathrm{min}}{M_\mathrm{Pl}}\lesssim 10^{-5}$, and only in the extreme possible regime where $\Omega_\mathrm{PBH,f}>10^{-3}$ we get that $ 10^{-5}\lesssim\frac{M_\mathrm{min}}{M_\mathrm{Pl}}\lesssim 10^{-1}$.

The gravitational N-body simulation in the Solar system was performed using different parallel approaches with the comparisons in the computational times and speed-up values being carried out under different model sizes and the number of processors. The numerical integration used is a second-order velocity Verlet approach which gives the acceptable accuracy in the orbits of major bodies and asteroids with a time step size of 0.1 days.

Xinping Zhou, Yuandeng Shen, Zehao Tang, Chengrui Zhou, Yadan Duan, Song Tang

8 pages, 5 figures, accepted for publication in A&A

The reflection, refraction, and transmission of large-scale extreme ultraviolet (EUV) waves (collectively, secondary waves) have been observed during their interactions with coronal structures such as active regions (ARs) and coronal holes (CHs). However, the effect of the total reflection of EUV waves has not been reported in the literature. Here, we present the first unambiguous observational evidence of the total reflection of a quasi-periodic EUV wave train during its interaction with a polar CH. The event occurred in NOAA AR 12473, located close to the southeast limb of the solar disk, and was characterized by a jet-like CME. In this study, we focus in particular on the driving mechanism s of the quasi-periodic wave train and the total reflection effect at the CH boundary. We find that the periods of the incident and the reflected wave trains are both about 100 seconds. The excitation of the quasi-periodic wave train was possibly due to the intermittent energy release in the associated flare since its period is similar to that of the quasi-periodic pulsations in the associated flare. Our observational results showed that the reflection of the wave train at the boundary of the CH was a total reflection because the measured incidence and critical angles satisfy the theory of total reflection, i.e., the incidence angle is less than the critical angle.

For rapidly rotating turbulence (Rossby number much less than unity), the standard mixing length theory for turbulent convection breaks but Coriolis force enters the force balance such that magnetic field eventually depends on rotation. By simplifying the self-sustained magnetohydrodynamics dynamo equations of electrically conducting fluid motion, with the aid of theory of isotropic non-rotating or anisotropic rotating turbulence driven by thermal convection, we make estimations and derive scaling laws for stellar magnetic fields for slow and fast rotation. Our scaling laws are in good agreement with the observations.

Martin Houde, Boy Lankhaar, Fereshteh Rajabi, Mohammed A. Chamma

20 pages, 8 figures, accepted for publication MNRAS

We discuss the existence of elliptical polarisation in rotational spectral lines of CO and other molecules within the context of the Anisotropic Resonant Scattering (ARS) model. We show that the effect of ARS on the radiation field can lead to not only the previously predicted transformation of background linear polarisation into circular polarisation (i.e., Faraday conversion), but also the occurrence of Faraday rotation and the generation of elliptically polarised signals in an otherwise initially unpolarised radiation field. This is due to a collective behaviour between the large number of molecules acting as a diffraction ensemble that strongly favours forward scattering over any other mode. Our application to astronomical data demonstrates the dependency of the Stokes parameters on the strength and orientation of the ambient magnetic field, and suggests that ARS will manifest itself for a wide range of molecular species and transitions.

M. M. Sardaneta, P. Amram, A. Boselli, B. Vollmer, M. Rosado, M. Sánchez-Cruces, A. Longobardi, C. Adami, M. Fossati, B. Epinat, M. Boquien, P. Côté, G. Hensler, Junais, H. Plana, J.C. Cuillandre, L. Ferrarese, J.L. Gach, J. A. Gomez-Lopez, S. Gwyn, G. Trinchieri

Accepted for publication on A&A

Using the VESTIGE survey, a deep narrow-band H$\alpha$ imaging survey of the Virgo cluster carried on at the CFHT with MegaCam, we discovered a long diffuse tail of ionised gas in the edge-on late-type galaxy NGC 4330. This peculiar feature witnesses an ongoing ram pressure stripping (RPS) event able to remove the gas in the outer disc region. Tuned hydrodynamic simulations suggest that the RPS event is occurring almost face-on, making NGC 4330 the ideal candidate to study the effects of the perturbation in the direction perpendicular to the disc plane. We present here two new independent sets of Fabry-Perot observations (R$\simeq$10000) in order to understand the effects of the RPS process on the ionised gas kinematics. Despite their limited sensitivity to the diffuse gas emission, the data allowed us to measure the velocity and the velocity dispersion fields over the galaxy disc and in several features at the edges or outside the stellar disc formed after the RPS event. We have constructed the position-velocity diagrams and the rotation curves of the galaxy using three different techniques. The data show, consistent with the hydrodynamic simulations, that the galaxy has an inner solid-body rotation up to $\sim$2.4 kpc, with non-circular streaming motions outwards the disc and in the several external features formed during the interaction of the galaxy with the surrounding intracluster medium. The data also indicate a decrease of the rotational velocity of the gas with increasing distance from the galaxy disc along the tails, suggesting a gradual but not linear loss of angular momentum in the stripped gas. Consistent with a RPS scenario, the $i$-band image shows a boxy shape at the southwest edge of the disc, where the stellar orbits might have been perturbed by the modification of the gravitational potential well of the galaxy due to the displacement of the gas in the $z$-direction.

Mario Ballardini, Fabio Finelli

16 pages, 8 figures

We study the use of type Ia Supernovae (SNe Ia) in the context of scalar-tensor theories of gravity, taking as a working example induced gravity, equivalent to Jordan-Brans-Dicke theory. Winking at accurate and precision cosmology, we test the correction introduced by a time variation of the Newton's constant, predicted by scalar-tensor theories, on the SNe distance modulus relation. We find that for induced gravity the coupling parameter is constrained from $\xi < 0.0095$ (95% CL) using Pantheon SNe data alone down to $\xi < 0.00063$ (95% CL) combining {\em Planck} DR3 CMB information together with a compilation of BAO measurements from BOSS DR12 and SNe data. In this minimal case the improvements in terms of constraints on the cosmological parameters coming from the addition of SNe data to CMB and BAO measurements is limited, $\sim 7\%$ on the 95% CL upper bound on $\xi$. Allowing for the value of the gravitational constant today to depart from the Newton's constant, we find that the addition of SNe further tightens the constraints obtained by CMB and BAO data on the standard cosmological parameters and by 22% on the coupling parameter, i.e. $\xi < 0.00064$ at 95% CL. We finally show that in this class of modified gravity models the use a prior on the absolute magnitude $M_B$ in combination with the Pantheon SNe sample leads to results which are very consistent with those obtained by imposing a prior on $H_0$, as happens for other {\em early} solutions which accommodate a larger value of $H_0$ compared to the $\Lambda$CDM results.

Teppei Minoda, Shintaro Yoshiura, Tomo Takahashi

18 pages, 6 figures, 1 table, Comments welcome

We argue that the 21-cm global signal can be a powerful probe of isocurvature perturbations, particularly for the ones with blue-tilted spectra. Although the 21-cm global signal is much affected by astrophysical processes, which give some uncertainties when cosmological models are investigated, recent results from HERA have constrained several astrophysical parameters, whose information can reduce the ambiguities originating from astrophysics. We show that the size and spectral tilt of isocurvature perturbations can be well inferred from the 21-cm global signal once the information on astrophysics from the HERA results is taken into account.

All Type IIn supernovae (SNe IIn) show narrow hydrogen emission lines in their spectra. Apart from this common feature, they demonstrate very broad diversity in brightness, duration, and morphology of their light curves, which indicates that they likely come from a variety of progenitor systems and explosion channels. A particular subset of SNe IIn, the so called SNe IIn-P, exhibit $\sim$100 days plateau phases that are very similar to the ones of the ordinary hydrogen-rich SNe (SNe II). In the past, SNe IIn-P were explained by the models of sub-energetic electron capture explosions surrounded by dense extended winds. In this work, we attempt to explain this class of SNe with standard red supergiant (RSG) progenitors that experience outbursts several month before the final explosion. The outburst energies that show the best agreement between our models and the data ($5\times10^{46}\,{\rm erg}$) fall at the low range of the outburst energies that have been observed for SNe IIn (between few times $10^{46}\,{\rm erg}$ and $10^{49}\,{\rm erg}$). Instead, the inferred explosion energy of SN 2005cl is relatively high ($1-2\times10^{51}\,{\rm erg}$) compared to the explosion energies of the ordinary SNe II. Our models provide alternative explanation of SNe IIn-P to the previously proposed scenarios.

K. Shinozaki, K. Bolmgren, D. Barghini, M. Battisti, A. Belov, M. Bertaina, F. Bisconti, G. Cambiè, F. Capel, M. Casolino, F. Fenu, A. Golzio, Z. Plebaniak, M. Przybylak, J. Szabelski, N. Sakaki, Y. Takizawa (for the JEM-EUSO Collaboration)

11 pages, 5 figures, presented in 37th International Cosmic Ray Conference (Berlin)

The JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) program aims at the realization of the ultra-high energy cosmic ray (UHECR) observation using wide field of view fluorescence detectors in orbit. Ultra-violet (UV) light emission from the atmosphere such as airglow and anthropogenic light on the Earth's surface are the main background for the space-based UHECR observations. The Mini-EUSO mission has been operated on the International Space Station (ISS) since 2019 which is the first space-based experiment for the program. The Mini-EUSO instrument consists of a 25 cm refractive optics and the photo-detector module with the 2304-pixel array of the multi-anode photomultiplier tubes. On the nadir-looking window of the ISS, the instrument is capable of continuously monitoring a ~300 km x 300 km area. In the present work, we report the preliminary result of the measurement of the UV light in the nighttime Earth using the Mini-EUSO data downlinked to the ground. We mapped UV light distribution both locally and globally below the ISS obit. Simulations were also made to characterize the instrument response to diffuse background light. We discuss the impact of such light on space-based UHECR observations and the Mini-EUSO science objectives.

Andrew J. Bunker

Appeared in proceedings of conference "Uncovering Early Galaxy Evolution in the ALMA and JWST Era", held in Viana do Castelo, Portugal, June 2019. Presentation on behalf of the NIRSpec Instrument Science Team and the JADES collaboration

I present an overview of the JWST Advanced Deep Extragalactic Survey (JADES), a joint program of the JWST/NIRCam and NIRSpec Guaranteed Time Observations (GTO) teams involving 950 hours of observation. We will target two well-studied fields with excellent supporting data (e.g., from HST-CANDELS): GOODS-North and South, including the Ultra Deep Field. The science goal of JADES is to chart galaxy evolution at z > 2, and potentially out to z > 10, using the rest-frame optical and near-IR though observations from $\approx$ 1 - 5 $\mu$m. Multi-colour NIRCam imaging with 9 filters will enable photometric redshifts and the application of the Lyman break technique out to unprecedented distances. NIRSpec spectroscopy (with spectral resolving powers of R = 100, 1000 & 2700) will measure secure spectroscopic redshifts of the photometrically-selected population, as well as stellar continuum slopes in the UV rest-frame, and hence study the role of dust, stellar population age, and other effects. Measuring emission lines can constrain the dust extinction, star formation rates, metallicity, chemical abundances, ionization and excitation mechanism in high redshift galaxies. Coupling NIRCam and NIRSpec observations will determine stellar populations (age, star formation histories, abundances) of galaxies and provide the information to correct their broad-band spectral energy distribution for likely line contamination. Potentially we can search for signatures of Population III stars such as HeII. We can address the contribution of star-forming galaxies at z > 7 to reionization by determining the faint end slope of the luminosity function and investigating the escape fraction of ionizing photons by comparing the UV stellar continuum with the Balmer-line fluxes.

M. S. Angelo, J. F. C. Santos Jr, F. F. S. Maia, W. J. B. Corradi

Accepted for publication in MNRAS

A number of stellar open cluster (OC) pairs in the Milky Way occupy similar positions in the phase space (coordinates, parallax and proper motions) and therefore may constitute physically interacting systems. The characterization of such objects based on observational data is a fundamental step towards a proper understanding of their physical status and to investigate cluster pair formation in the Galaxy. In this work, we employed Gaia EDR3 data to investigate a set of 16 OCs distributed as seven stellar aggregates. We determined structural parameters and applied a decontamination technique that allowed to obtain unambiguous lists of member stars. The studied OCs span Galactocentric distances and ages in the ranges ~7 < $R_G$ (kpc) < ~11 and 7.3 <= log t <= 9.2. Eight OCs were found to constitute 4 gravitationally bound pairs (NGC5617-Trumpler22, Collinder394-NGC6716, Ruprecht100-Ruprecht101, NGC659-NGC663, the latter being a dynamically unevolved binary) and other 4 clusters constitute 2 interacting, but gravitationally unbound, pairs (King16-Berkeley4, NGC2383-NGC2384, the latter being a dissolving OC). Other 4 OCs (Dias1, Pismis19, Czernik20, NGC1857) seem not associated to any stellar aggregates. Apparently, clusters within bound and dynamically evolved pairs tend to present ratios of half-light to tidal radius larger than single clusters located at similar $R_G$, suggesting that mutual tidal interactions may possibly affect their structural parameters. Unbound or dynamically unevolved systems seems to present less noticeable signature of tidal forces on their structure. Moreover, the core radius seems more importantly correlated with the clusters' internal dynamical relaxation process.

F. B. M. dos Santos, J. E. Gonzalez, R. Silva

19 pages, 4 figures, 3 tables

We establish new constraints on $f(T)$ gravity models by using cosmological data. In particular, we investigate the restrictions given by the gas mass fraction measurements of galaxy clusters and transversal BAO data. Both data sets are regarded as weakly dependent on a fiducial cosmology. In addition, we also include a CMB measurement of the temperature power spectrum first peak, along with $H(z)$ values from cosmic chronometers and supernovae data from the Pantheon data set. We also perform a forecast for future constraints on the deviation of $f(T)$ models from the $\Lambda$CDM scenario by following the specifications of the J-PAS and Euclid surveys and find significant improvements on the constraints of the $b$-parameter, when compared to the results of the statistical analysis.

A.D. Dolgov

7 pages, 2 figures, based on the invited talks at 20th Lomonosov Conference on Elementary Particle Physics,10th International Conference on New Frontiers in Physics, Advances in Quantum Field Theory - 2021

Recent astronomical observations indicating a strikingly abundant presence of antimatter in the Galaxy, in particular, of anti-stars are reviewed. Long-time earlier theoretical predictions are briefly discussed.

Shuai Zha, Evan P. O'Connor, Sean M. Couch, Shing-Chi Leung, Ken'ichi Nomoto

11 pages, 12 figures, progenitor models available at zenodo, this https URL

We present neutrino-transport hydrodynamic simulations of electron-capture supernovae (ECSNe) in \texttt{FLASH} with new two-dimensional (2D) collapsing progenitor models. These progenitor models feature the 2D modelling of oxygen-flame propagation until the onset of core collapse. We perform axisymmetric simulations with 6 progenitor models that, at the time of collapse, span a range of propagating flame front radii. For comparison, we also perform a simulation with the same setup using the canonical, spherically-symmetrical progenitor model n8.8. We found that the variations in the progenitor models inherited from simulations of stellar evolution and flame propagation do not significantly alter the global properties of the neutrino-driven ECSN explosion, such as the explosion energy ($\sim1.36$-$1.48\times10^{50}$ erg) and the mass ($\sim0.017$-$0.018M_\odot$) and composition of the ejecta. Due to aspherical perturbations induced by the 2D flame, the ejecta contains a small amount ($\lesssim1.8\times10^{-3}~M_\odot$) of low-$Y_e$ ($0.35<Y_e<0.4$) component. The baryonic mass of the protoneutron star is $\sim1.34~M_\odot$ ($\sim1.357~M_\odot$) with the new (n8.8) progenitor models when simulations end at $\sim400$ ms and the discrepancy is due to updated weak-interaction rates in the progenitor evolutionary simulations. Our results reflect the nature of ECSN progenitors containing a strongly degenerate ONeMg core and suggest a standardized ECSN explosion initialized by ONeMg core collapse. Moreover, we carry out a rudimentary three-dimensional simulation and find that the explosion properties are fairly compatible with the 2D counterpart. Our paper facilitates a more thorough understanding of ECSN explosions following the ONeMg core collapse, though more three-dimensional simulations are still needed.

Anthony Lagain, Mikhail Kreslavsky, David Baratoux, Yebo Liu, Hadrien Devillepoix, Philip Bland, Gretchen K. Benedix, Luc S. Doucet, Konstantinos Servis

45 pages, 8 figures, accepted in Earth and Planetary Science Letters, 28/12/2021

The impact flux over the last 3 Ga in the inner Solar System is commonly assumed to be constant through time. However, asteroid break-up events in the main belt may have been responsible for cratering spikes over the last ~2 Ga on the Earth-Moon system. We investigate here the possible variations of the size frequency distributions of impactors from the record of small craters of 521 martian impact craters larger than 20 km in diameter. We show that 49 craters (out of the 521) correspond to the complete crater population of this size formed over the last 600 Ma. Our results on Mars show that the flux of both small (> 5 m) and large asteroids (> 1 km) are coupled, does not vary between each other over the last 600 Ma. Existing data sets for large craters on the Earth and the Moon are analyzed and compared to our results on Mars. On Earth, we infer the formation location of a set of impact craters thanks to plate tectonic reconstruction and show that a cluster of craters formed during the Ordovician period, about 470 Ma ago, appears to be a preservation bias. On the Moon, the late increase seen in the crater age signal can be due to the uncertain calibration method used to date those impacts (i.e. rock abundance in lunar impact ejecta), and other calibrations are consistent with a constant crater production rate. We conclude to a coupling of the crater production rate between kilometer-size craters and down to ~100 m in diameter in the inner Solar System. This is consistent with the traditional model for delivering asteroids to planet-crossing orbits: the Yarkovsky effect slowly pushes the large debris from asteroid break-ups towards orbital resonances while smaller debris are grinded through collisional cascades. This suggests that the influence of past asteroid break-ups in the cratering rate for D > 100 m is limited or inexistent.

Sujatha Ramakrishnan (IUCAA), Premvijay Velmani (IUCAA)

6 figures, 7 tables, submitted to MNRAS

The structural and dynamic properties of the dark matter halos, though an important ingredient in understanding large-scale structure formation, require more conservative particle resolution than those required by halo mass alone in a simulation. This reduces the parameter space of the simulations, more severely for high-redshift and large-volume mocks which are required by the next-generation large sky surveys. Here, we incorporate redshift and cosmology dependence into an algorithm that assigns accurate halo properties such as concentration, spin, velocity, and spatial distribution to the sub-resolution haloes in a simulation. By focusing on getting the right correlations with halo mass and local tidal anisotropy $\alpha$ measured at $4 \times$ halo radius, our method will also recover the correlations of these small scale structural properties with the large-scale environment, i.e., the halo assembly bias at all scales greater than $5 \times$ halo radius. We find that the distribution of halo properties is universal with redshift and cosmology. By applying the algorithm to a large volume simulation $(600 h^{-1}{\rm Mpc})$, we can access the $30-500$ particle haloes, thus gaining an order of magnitude in halo mass and two to three orders of magnitude in number density at $z=2-4$. This technique reduces the cost of mocks required for the estimation of covariance matrices, weak lensing studies, or any large-scale clustering analysis with less massive haloes.

Piotr A. Dybczyński, Małgorzata Królikowska

11 pages, 9 figures, submitted to A&A

In June 2021 the discovery of an unusual comet C/2014 UN271 Bernardinelli-Bernstein has been announced. Its cometary activity beyond Uranus orbit also has refreshed interest in similar objects, including C/2017K2 PanSTARRS. Another peculiarity of these objects is the long interval of positional data, taken at large heliocentric distances. These two comets are suitable candidates for a detailed investigation of their long-term motion outside the planetary zone. Using the selected orbital solutions, we aim at estimating the orbital parameters of their orbits at the previous perihelion passage. This might allow us to discriminate between dynamically old and new comets. To follow the dynamical evolution of long-period comets far outside the planetary zone, it is necessary to take into account both the perturbation caused by the overall Galactic gravitational potential and the actions of individual stars appearing in the solar neighborhood. To this aim, we applied the recently published methods based on stellar perturbers ephemerides. For C/2014 UN271 we obtained a precise orbital solution that can be propagated to the past and to the future. For C/2017 K2 we have to limit ourselves to study only the past motion since some signs of nongravitational effects can be found in recent positional observations. Therefore, we use a specially selected orbital solution suitable for past motion studies. Using these starting orbits, we propagated both comets to their previous perihelia. We also investigated the future motion of C/2014 UN271. Orbital evolution of these two comets appears to be sensitive to perturbations from several stars that closely approach the Sun. Unfortunately, some of these stars have 6D data with uncertainties too large to obtain definitive results for the studied comets; however, it appears that both comets were probably outside the planetary zone in the previous perihelion.

Stanislav Polyakov, Andrey Demichev, Alexander Kryukov, Evgeny Postnikov

In Proceedings of 5th International Workshop on Deep Learning in Computational Physics (DLCP2021), 28-29 June, 2021, Moscow, Russia

Extensive air showers created by high-energy particles interacting with the Earth atmosphere can be detected using imaging atmospheric Cherenkov telescopes (IACTs). The IACT images can be analyzed to distinguish between the events caused by gamma rays and by hadrons and to infer the parameters of the event such as the energy of the primary particle. We use convolutional neural networks (CNNs) to analyze Monte Carlo-simulated images from the telescopes of the TAIGA experiment. The analysis includes selection of the images corresponding to the showers caused by gamma rays and estimating the energy of the gamma rays. We compare performance of the CNNs using images from a single telescope and the CNNs using images from two telescopes as inputs.

Christine C. Dantas (Astrophysics Division, INPE, Brazil)

22 pages, 8 figures, submitted

We revisited the problem of "mixing" in a gravitational N-body system from the point of view of the ordering of coarse-grained cells in the one-particle energy space, here denoted {\it energy ranking preservation} (ERP) analysis. We investigated a subset of the IllustrisTNG cosmological magnetohydrodyna\-mical simulations, considering both their full and dark-only versions. For each simulation, we extracted data from the $4$ most massive ("reference") FOF halos at redshift $z=0$, which were analysed separately. The particle energies in those halos were sorted and partitioned into bins in terms of quintiles and deciles. Then we identified such particles at higher redshifts, consi\-dering only if they were residing in FOF halos, and assigned them to the same initially defined energy bins. We found evidence of ERP, monotonically declining as a function of redshift, reference halo mass and particle type. Our results confirmed previous indications in the literature, obtained for dark matter-only simu\-lations, of a (hypothetical) ``mesoscopic'' constraint, pertinent at a collective level in the energy space. We extended previous results to the baryonic component, raising the hypothesis that such a mesoscopic constraint, operative in the context of the gravitational N-body problem, can partially prevail over dissipational mechanisms. In a coarse-grained sense, our results indicated that, roughly, the most (less) gravitationally bounded masses today were probably the most (less) bounded ones at redshifts even as high as $z \sim 5$.

Alessandro Morbidelli, Kevin Baillie, Konstantin Batygin, Sebastien Charnoz, Tristan Guillot, David C. Rubie, Thorsten Kleine

Published online in Nature Astronomy on Dec. 22, 2021

The formation of planetesimals is expected to occur via particle-gas instabilities that concentrate dust into self-gravitating clumps. Triggering these instabilities requires the prior pileup of dust in the protoplanetary disk. Until now, this has been successfully modeled exclusively at the disk's snowline, whereas rocky planetesimals in the inner disk were obtained only by assuming either unrealistically large particle sizes or an enhanced global disk metallicity. However, planetesimal formation solely at the snowline is difficult to reconcile with the early and contemporaneous formation of iron meteorite parent bodies with distinct oxidation states and isotopic compositions, indicating formation at different radial locations in the disk. Here, by modeling the evolution of a disk with ongoing accretion of material from the collapsing molecular cloud, we show that planetesimal formation may have been triggered within the first 0.5 million years by dust pileup at both the snowline (at approximately 5 au) and the silicate sublimation line (at approximately 1 au), provided turbulent diffusion was low. Particle concentration at approximately 1 au is due to the early outward radial motion of gas and is assisted by the sublimation and recondensation of silicates. Our results indicate that, although the planetesimals at the two locations formed about contemporaneously, those at the snowline accreted a large fraction of their mass (approximately 60 percent) from materials delivered to the disk in the first few 10,000 yr, whereas this fraction is only 30 percent for the planetesimals formed at the silicate line. Thus, provided that the isotopic composition of the delivered material changed with time, these two planetesimal populations should have distinct isotopic compositions, consistent with observations.

At the KATRIN experiment, the electron neutrino mass is inferred from the shape of the $\beta$-spectrum of tritium. Important systematic effects in the Windowless Gaseous Tritium Source (WGTS) of the experiment include the energy loss by electron scattering, and the extended starting potential. In the WGTS, primary high-energy electrons from $\beta$-decay produce an extended secondary spectrum of electrons through various atomic and molecular processes including ionization, recombination, cluster formation and scattering. This electron spectrum plays a role in understanding electron energy loss processes, but also for the simulation of plasma processes. These simulations will then provide an insight on the starting potential. Here, a Monte Carlo approach is used to model the electron spectrum for a given magnetic and electric field configuration. The spectrum is evaluated at different positions within the WGTS, which allows for a direct analysis of the spectrum close to rear wall and detector end of the experiment. Alongside electrons, also ions are tracked by the simulation.

Siyu Chen, Hong-Hao Zhang, Guangbo Long

8 pages, 6 figures, comments welcome

We revisit the constraints on primordial black holes (PBHs) in the mass range $10^{13}-10^{18}$ g by comparing the 100\,keV-5\,GeV gamma-ray background with isotropic flux from PBH Hawking radiation (HR). We investigate three effects that may update the constraints on the PBH abundance; i) reliably calculating the secondary spectra of HR for energy below 5\,GeV, ii) the contributions to the measured isotropic flux from the Galactic PBH HR and that from annihilation radiation due to evaporated positrons, iii) inclusion of astrophysical background from gamma-ray sources. The conservative constraint is significantly improved by more than an order of magnitude at $2\times10^{16}$g$\lesssim M\lesssim 10^{17}$g over the past relevant work, where the effect ii is dominant. After further accounting for the astrophysical background, more than a tenfold improvement extends to a much wider mass range $10^{15}$g$\lesssim M\lesssim 2\times 10^{17}$g.

Mouza Almualla, Yuhong Ning, Mattia Bulla, Tim Dietrich, Michael W. Coughlin, Nidhal Guessoum

On the 17th of August, 2017 came the simultaneous detections of GW170817, a gravitational wave that originated from the coalescence of two neutron stars, along with the gamma-ray burst GRB170817A, and the kilonova counterpart AT2017gfo. Since then, there has been much excitement surrounding the study of neutron star mergers, both observationally, using a variety of tools, and theoretically, with the development of complex models describing the gravitational-wave and electromagnetic signals. In this work, we improve upon our pipeline to infer kilonova properties from observed light-curves by employing a Neural-Network framework that reduces execution time and handles much larger simulation sets than previously possible. In particular, we use the radiative transfer code POSSIS to construct 5-dimensional kilonova grids where we employ different functional forms for the angular dependence of the dynamical ejecta component. We find that incorporating an angular dependence improves the fit to the AT2017gfo light-curves by up to ~50% when quantified in terms of the weighted Mean Square Error.

P. Gural (1), T. Mills (2), M. Mazur (2), P. Brown (2) ( (1) Gural Software and Analysis LLC, USA, (2) University of Western Ontario, Canada)

50 pages, 19 figures, accepted to Experimental Astronomy

The mass ranges of meteors, imaged by electro-optical (EO) cameras and backscatter radar receivers, for the most part do not overlap. Typical EO systems detect meteoroid masses down to 10$^{-5}$ kg or roughly magnitude +2 meteors when using moderate field of view optics, un-intensified optical components, and meteor entry velocities around 45 km/sec. This is near the high end of the mass range of typical meteor radar observations. Having the same mass meteor measured by different sensor wavelength bands would be a benefit in terms of calibrating mass estimations for both EO and radar. To that end, the University of Western Ontario (UWO) has acquired and deployed a very low light imaging system based on an electron-multiplying CCD camera technology. This embeds a very low noise, per pixel intensifier chip in a cooled camera setup with various options for frame rate, region of interest and binning. The EO system of optics and sensor was optimally configured to collect 32 frames per second in a square field of view 14.7 degrees on a side, achieving a single-frame stellar limiting magnitude of m$_G$ = +10.5. The system typically observes meteors of +6.5. A key development in this pipeline has been the first true application of matched filter processing to process the faintest meteors possible in the EMCCD system while also yielding high quality automated metric measurements of meteor focal plane positions. With pairs of EMCCD systems deployed at two sites, triangulation and high accuracy orbits are one of the many products being generated by this system. These measurements will be coupled to observations from the Canadian Meteor Orbit Radar (CMOR) used for meteor plasma characterization and the Canadian Automated Meteor Observatory (CAMO) high resolution mirror tracking system.

Arshia M. Jacob, Karl M. Menten, Friedrich Wyrowski, Benjamin Winkel, David A. Neufeld, Baerbel S. Koribalski

Accepted for publication in Astronomy and Astrophysics 16 pages, 11 figures, 3 tables

Along several sight lines within the Milky Way ArH+ has been ubiquitously detected with only one detection in extragalactic environments, namely along two sight lines in the red shift z=0.89 absorber towards the lensed blazar PKS 1830-211. Being formed in predominantly atomic gas by reactions between Ar+, which were initially ionised by cosmic rays and molecular hydrogen, ArH+ has been shown to be an excellent tracer of atomic gas as well as the impinging cosmic-ray ionisation rates. In this work, we attempt to extend the observations of ArH+in extragalactic sources to examine its use as a tracer of the atomic interstellar medium (ISM) in these galaxies. We report the detection of ArH+ towards two luminous nearby galaxies, NGC 253 and NGC 4945, and the non-detection towards Arp 220 observed using the SEPIA660 receiver on the APEX 12 m telescope. In addition, the two sidebands of this receiver allowed us to observe the NKaKc=1_1,0-1_0,1 transitions of another atomic gas tracer p-H2O+ at 607.227 GHz with the ArH+ line, simultaneously. We modelled the optically thin spectra of both species and compared their observed line profiles with that of other well-known atomic gas tracers such as OH+ and o-H2O+ and diffuse and dense molecular gas tracers HF and CO, respectively. By further assuming that the observed absorption from the ArH+, OH+, and H2O+ molecules are affected by the same flux of cosmic rays, we investigate the properties of the different cloud layers based on a steady-state analysis of the chemistry of these three species.

Andre Izidoro, Rajdeep Dasgupta, Sean N. Raymond, Rogerio Deienno, Bertram Bitsch, Andrea Isella

Published in Nature Astronomy on Dec 30, 2021. Authors' version including Methods and Supplementary Information

Astronomical observations reveal that protoplanetary disks around young stars commonly have ring- and gap-like structures in their dust distributions. These features are associated with pressure bumps trapping dust particles at specific locations, which simulations show are ideal sites for planetesimal formation. Here we show that our Solar System may have formed from rings of planetesimals -- created by pressure bumps -- rather than a continuous disk. We model the gaseous disk phase assuming the existence of pressure bumps near the silicate sublimation line (at $T \sim$1400~K), water snowline (at $T \sim$170~K), and CO-snowline (at $T \sim$30~K). Our simulations show that dust piles up at the bumps and forms up to three rings of planetesimals: a narrow ring near 1~au, a wide ring between $\sim$3-4~au and $\sim$10-20~au, and a distant ring between $\sim$20~au and $\sim$45~au. We use a series of simulations to follow the evolution of the innermost ring and show how it can explain the orbital structure of the inner Solar System and provides a framework to explain the origins of isotopic signatures of Earth, Mars and different classes of meteorites. The central ring contains enough mass to explain the rapid growth of the giant planets' cores. The outermost ring is consistent with dynamical models of Solar System evolution proposing that the early Solar System had a primordial planetesimal disk beyond the current orbit of Uranus.

We investigate the cosmology of mini Primordial Black Holes (PBHs) produced by large density perturbations that collapse during a stiff fluid domination phase. Such a phase can be realized by a runaway-inflaton model that crosses an inflection point or a sharp feature at the last stage of inflation. Mini PBHs evaporate promptly and reheat the early universe. In addition, we examine two notable implications of this scenario: the possible presence of PBH evaporation remnants in galaxies and a non-zero residual potential energy density for the runaway inflaton that might play the role of the dark energy. We specify the parameter space that this scenario can be realized and we find that a transit PBH domination phase is necessary due to gravitational wave (GW) constraints. A distinct prediction of the scenario is a compound GW signal that might be probed by current and future experiments. We also demonstrate our results employing an explicit inflation model.

The coherent oscillation of ultralight dark matter induces changes in gravitational potential with the frequency in nanohertz range. This effect is known to produce a monochromatic signal in the pulsar timing residual. Here we discuss a multi fields scenario that produces a wide spectrum of frequencies, such that the ultralight particle oscillation can mimic the pulsar timing signal of stochastic gravitational wave background. We discuss how ultralight dark matter with various spins produces such a wideband spectrum on pulsar timing residuals and perform the Bayesian analysis to constrain the parameters.

Debasish Borah (1), Arnab Dasgupta (2), Satyabrata Mahapatra (3), Narendra Sahu (3) ((1) Indian Institute of Technology Guwahati, (2) University of Pittsburgh, (3) Indian Institute of Technology Hyderabad)

7 Pages, 5 Captioned Figures

We propose a novel and minimal framework where a light scalar field can give rise to dark matter (DM) self-interactions while enhancing the CP asymmetry required for successful leptogenesis. The lightest among the right handed neutrinos (RHN) introduced for generating light neutrino masses radiatively, play the role of DM while the heavier two can play non-trivial roles in generating DM relic as well as lepton asymmetry. While dark matter self-interactions mediated by the singlet scalar can alleviate the small scale issues of cold dark matter paradigm, the same scalar can give rise to new one-loop decay processes of heavy RHN into standard model leptons providing an enhanced contribution to CP asymmetry, even with sub-TeV scale RHN mass. The thermally under-abundant relic of DM due to large annihilation rates into its light mediator receives a late non-thermal contribution from a heavier RHN. With only five new particles each having non-trivial roles in generating DM relic and baryon asymmetry, the model can explain non-zero neutrino mass while being verifiable at different experiments related to DM direct detection, flavour physics and colliders.

Magnetic reconnection has been suggested to play an important role in the dynamics and energetics of plasma turbulence by spacecraft observations, simulations and theory over the past two decades, and recently, by magnetosheath observations of MMS. A new method based on magnetic flux transport (MFT) has been developed to identify reconnection activity in turbulent plasmas. This method is applied to a gyrokinetic simulation of two-dimensional (2D) plasma turbulence. Results on the identification of three active reconnection X-points are reported. The first two X-points have developed bi-directional electron outflow jets. Beyond the category of electron-only reconnection, the third X-point does not have bi-directional electron outflow jets because the flow is modified by turbulence. In all cases, this method successfully identifies active reconnection through clear inward and outward flux transport around the X-points. This transport pattern defines reconnection and produces a new quadrupolar structure in the divergence of MFT. This method is expected to be applicable to spacecraft missions such as MMS, Parker Solar Probe, and Solar Orbiter.

Each grid block in a 3D geological model requires a rock type that represents all physical and chemical properties of that block. The properties that classify rock types are lithology, permeability, and capillary pressure. Scientists and engineers determined these properties using conventional laboratory measurements, which embedded destructive methods to the sample or altered some of its properties (i.e., wettability, permeability, and porosity) because the measurements process includes sample crushing, fluid flow, or fluid saturation. Lately, Digital Rock Physics (DRT) has emerged to quantify these properties from micro-Computerized Tomography (uCT) and Magnetic Resonance Imaging (MRI) images. However, the literature did not attempt rock typing in a wholly digital context. We propose performing Digital Rock Typing (DRT) by: (1) integrating the latest DRP advances in a novel process that honors digital rock properties determination, while; (2) digitalizing the latest rock typing approaches in carbonate, and (3) introducing a novel carbonate rock typing process that utilizes computer vision capabilities to provide more insight about the heterogeneous carbonate rock texture.

Simon Clery, Yann Mambrini, Keith A. Olive, Sarunas Verner

15 pages, 4 figures, 2 tables

We consider the production of matter and radiation during reheating after inflation, restricting our attention solely to gravitational interactions. Processes considered are the exchange of a graviton, $h_{\mu \nu}$, involved in the scattering of the inflaton or particles in the newly created radiation bath. In particular, we consider the gravitational production of dark matter (scalar or fermionic) from the thermal bath as well as from scattering of the inflaton condensate. We also consider the gravitational production of radiation from inflaton scattering. In the latter case, we also derive a lower bound on the maximal temperature of order of $10^{12}$ GeV for a typical $\alpha-$attractor scenario from $\phi \phi \rightarrow h_{\mu \nu} \rightarrow$ Standard Model fields (dominated by the production of Higgs bosons). This lower gravitational bound becomes the effective maximal temperature for reheating temperatures, $T_{\rm{RH}} \lesssim 10^9$ GeV. The processes we consider are all minimal in the sense that they are present in any non-minimal extension of the Standard Model theory based on Einstein gravity and can not be neglected. We compare each of these processes to determine their relative importance in the production of both radiation and dark matter.