New submissions for Friday, 21 June 2024

Auto update Star Formation & Molecular Cloud papers at about 2:30am UTC (10:30am Beijing time) every weekday.

阅读 Usage.md了解如何使用此repo实现个性化的Arxiv论文推送

See Usage.md for instructions on how to personalize the repo.

Keyword list: ['star formation', 'star-forming', 'molecular cloud', 'interstellar medium', 'cloud', 'clump', 'core', 'filament', 'atomic gas', 'N-PDF']

Excluded: ['galaxies', 'galaxy cluster', ' AGN ']

Today: 15papers

Large Interferometer For Exoplanets (LIFE): XIII. The Value of Combining Thermal Emission and Reflected Light for the Characterization of Earth Twins

• Authors: E. Alei, S. P. Quanz, B. S. Konrad, E. O. Garvin, V. Kofman, A. Mandell, D. Angerhausen, P. Mollière, M. R. Meyer, T. Robinson, S. Rugheimer, the LIFE Collaboration

• Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)

• Arxiv link: https://arxiv.org/abs/2406.13037

• Pdf link: https://arxiv.org/pdf/2406.13037

• Abstract Following the recommendations to NASA and ESA, the search for life on exoplanets will be a priority in the next decades. Two direct imaging space mission concepts are being developed: the Habitable Worlds Observatory (HWO) and the Large Interferometer for Exoplanets (LIFE). HWO focuses on reflected light spectra in the ultraviolet/visible/near-infrared (UV/VIS/NIR), while LIFE captures the mid-infrared (MIR) emission of temperate exoplanets. We assess the potential of HWO and LIFE in characterizing a cloud-free Earth twin orbiting a Sun-like star at 10 pc, both separately and synergistically, aiming to quantify the increase in information from joint atmospheric retrievals on a habitable planet. We perform Bayesian retrievals on simulated data from an HWO-like and a LIFE-like mission separately, then jointly, considering the baseline spectral resolutions currently assumed for these concepts and using two increasingly complex noise simulations. HWO would constrain H$_2$O, O$_2$, and O$_3$, in the atmosphere, with ~ 100 K uncertainty on the temperature profile. LIFE would constrain CO$_2$, H$_2$O, O$_3$ and provide constraints on the thermal atmospheric structure and surface temperature (~ 10 K uncertainty). Both missions would provide an upper limit on CH$_4$. Joint retrievals on HWO and LIFE data would accurately define the atmospheric thermal profile and planetary parameters, decisively constrain CO$_2$, H$_2$O, O$_2$, and O$_3$, and weakly constrain CO and CH$_4$. The detection significance is greater or equal to single-instrument retrievals. Both missions provide specific information to characterize a terrestrial habitable exoplanet, but the scientific yield is maximized with synergistic UV/VIS/NIR+MIR observations. Using HWO and LIFE together will provide stronger constraints on biosignatures and life indicators, potentially transforming the search for life in the universe.

Why are (almost) all the protostellar outflows aligned in Serpens Main?

• Authors: Joel D. Green, Klaus M. Pontoppidan, Megan Reiter, Dan M. Watson, Sachindev S. Shenoy, P. Manoj, Mayank Narang

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2406.13084

• Pdf link: https://arxiv.org/pdf/2406.13084

• Abstract We present deep 1.4-4.8 um JWST-NIRCam imaging of the Serpens Main star-forming region and identify 20 candidate protostellar outflows, most with bipolar structure and identified driving sources. The outflow position angles (PAs) are strongly correlated, and aligned within +/- 24 degrees of the major axis of the Serpens filament. These orientations are further aligned with the angular momentum vectors of the two disk shadows in this region. We estimate that the probability of this number of young stars being co-aligned if sampled from a uniform PA distribution is 10^-4. This in turn suggests that the aligned protostars, which seem to be at similar evolutionary stages based on their outflow dynamics, formed at similar times with a similar spin inherited from a local cloud filament. Further, there is tentative evidence for a systematic change in average position angle between the north-western and south-eastern cluster, as well as increased scatter in the PAs of the south-eastern protostars. SOFIA-HAWC+ archival dust polarization observations of Serpens Main at 154 and 214 um are perpendicular to the dominant jet orientation in NW region in particular. We measure and locate shock knots and edges for all of the outflows and provide an identifying catalog. We suggest that Serpens main is a cluster that formed from an isolated filament, and due to its youth retains its primordial outflow alignment.

Magnetohydrodynamic simulation of the 2012-July-12 CME Event With the Fluxrope-G3DMHD Model

• Authors: Chin-Chun Wu (1,a)Kan Liou (2,b)Brian Wood (1,c)Keiji Hayashi (3,d)

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

• Arxiv link: https://arxiv.org/abs/2406.13090

• Pdf link: https://arxiv.org/pdf/2406.13090

• Abstract Coronal mass ejections (CMEs) and their driven shocks are a major source of large geomagnetic storms due to their large and long-lasting, southward component of magnetic field in the sheath and the flux rope (e.g., magnetic cloud). Predicting the strength and arrival time of southward fields accurately thus plays a key role in space weather predictions. To address this problem, we have developed a new model, which combines the global three-dimensional, time-dependent, magnetohydrodynamic (MHD), data-driven model (G3DMHD) and a self-contained magnetic flux-rope model [1]. As a demonstration and validation, here we simulate the evolution of a Sun-Earth-directed CME that erupted on 2012-July-12. The computational domain spans from 2.5 solar radii (Rs) from the surface of the Sun, where the flux rope is injected, to 245 Rs. We compare the time profiles of the simulated MHD parameters (Density, velocity, temperature, and magnetic field) with in situ solar wind observations acquired at ~1 AU by the Wind spacecraft and the result is encouraging. The model successfully reproduces the shock, sheath, and flux rope similar to those observed by Wind.

Multi-messenger modeling of the Monogem pulsar halo

• Authors: Youyou Li, Oscar Macias, Shinichiro Ando, Jacco Vink

• Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

• Arxiv link: https://arxiv.org/abs/2406.13426

• Pdf link: https://arxiv.org/pdf/2406.13426

• Abstract The High-Altitude Water Cherenkov Telescope (HAWC) has detected TeV halos associated with two nearby pulsars/pulsar wind nebulae (PWN) -- Geminga and B0656+14. These TeV halos extend up to tens of pc from the central accelerators, indicating that the diffusion of ultrarelativistic electrons and positrons in the interstellar medium has been suppressed by two orders of magnitude. Although Geminga and B0656+14 are at similar distances and in the same field of view, they have distinct histories. Notably, B0656+14 probably still resides within its parent supernova remnant, the Monogem Ring, which can be observed in X-rays. In this work, we perform high-resolution simulations of the propagation and emission of relativistic lepton pairs around B0656+14 using a two-zone diffusion model using the GALPROP numerical code. We compared the predicted inverse-Compton spectrum to the observations made by HAWC and Fermi-LAT and found physically plausible model parameters that resulted in a good fit to the data. Additionally, we estimated the contribution of this TeV-halo to the positron flux observed on Earth and found it to be smaller than 10% of the measured flux. We conclude that future observations of the TeV halo and its synchrotron emission counterpart in radio and X-ray frequencies will be crucial to distinguish between various possible models.

12C+12C Reaction Rates and the Evolution of a Massive Star

• Authors: Gwangeon Seong, Yubin Kim, Kyujin Kwak, Sunghoon Ahn, Chaeyeon Park, Kevin Insik Hahn, Chunglee Kim

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2406.13458

• Pdf link: https://arxiv.org/pdf/2406.13458

• Abstract Carbon fusion is important to understand the late stages in the evolution of a massive star. Astronomically interesting energy ranges for the 12C+12C reactions have been, however, poorly constrained by experiments. Theoretical studies on stellar evolution have relied on reaction rates that are extrapolated from those measured in higher energies. In this work, we update the carbon fusion reaction rates by fitting the astrophysical S-factor data obtained from direct measurements based on the Fowler, Caughlan, & Zimmerman (1975) formula. We examine the evolution of a 20 M_sun star with the updated 12C+12C reaction rates performing simulations with the MESA (Modules for Experiments for Stellar Astrophysics) code. Between 0.5 and 1 GK, the updated reaction rates are 0.35 to 0.5 times less than the rates suggested by Caughlan and Fowler (1988). The updated rates result in the increase of core temperature by about 7% and of the neutrino cooling by about a factor of three. Moreover, the carbon-burning lifetime is reduced by a factor of 2.7. The updated carbon fusion reaction rates lead to some changes in the details of the stellar evolution model, their impact seems relatively minor compared to other uncertain physical factors like convection, overshooting, rotation, and mass-loss history. The astrophysical S-factor measurements in lower energies have large errors below the Coulomb barrier. More precise measurements in lower energies for the carbon burning would be useful to improve our study and to understand the evolution of a massive star.

Insights into the Production of $^{44}$Ti and Nickel Isotopes in Core-Collapse Supernovae

• Authors: Tianshu Wang, Adam Burrows

• Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2406.13746

• Pdf link: https://arxiv.org/pdf/2406.13746

• Abstract We report nucleosynthetic results for both $^{44}$Ti and nickel isotopes for eighteen three-dimensional (3D) core-collapse supernova (CCSN) simulations extended to $\sim$20 seconds after bounce. We find that many of our long-term models are able to achieve $^{44}$Ti/$^{56}$Ni ratios similar to that observed in Cassiopeia A, and modern supernova models can synthesize up to $2\times10^{-4}M_\odot$ of $^{44}$Ti. Neutrino-driven winds and the fact that there can be simultaneous accretion and explosion in 3D models of core-collapse supernovae play central roles in its production. We conclude that the $^{44}$Ti underproduction problem in previous CCSN models is no longer an issue. In addition, we discuss the production of both $^{57}$Ni and stable nickel/iron ratios and compare our results to observations of SN1987A and the Crab.

Novae: An Important Source of Lithium in the Galaxy

• Authors: Jun Gao, Chunhua Zhu, Guoliang Lü, Jinlong Yu, Lin Li, Helei Liu, Sufen Guo

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2406.13986

• Pdf link: https://arxiv.org/pdf/2406.13986

• Abstract The source of the Galactic Lithium (Li) has long been a puzzle. With the discovery of Li in novae, extensive research has been conducted. However, there still exists a significant disparity between the observed abundance of lithium in novae and the existing theoretical predictions. Using the Modules for Experiments in Stellar Astrophysics (MESA), we simulate the evolution of nova with element diffusion and appropriately increased the amount of 3^He in the mixtures. Element diffusion enhances the transport efficiency between the nuclear reaction zone and the convective region on the surface of the white dwarf during nova eruptions, which results in more 7^Be to be transmitted to the white dwarf surface and ultimately ejected. Compared to the previous predictions, the abundance of 7^Be in novae simulated in our model significantly increases. And the result is able to explain almost all observed novae. Using the method of population synthesis, we calculate Li yield in the Galaxy. We find that the Galactic occurrence rate of nova is about 130 yr^{-1}, and about 110M Li produced by nova eruption is ejected into the interstellar medium (ISM). About 73% of Li in the Galactic ISM originates from novae, and approximately 15%-20% of the entire Galaxy. It means that novae are the important source of Li in the Galactic.

High-energy Neutrino Emission from NGC 1068 by Outflow-cloud Interactions

• Authors: Yong-Han Huang, Kai Wang, Zhi-Peng Ma

• Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

• Arxiv link: https://arxiv.org/abs/2406.14001

• Pdf link: https://arxiv.org/pdf/2406.14001

• Abstract As the hottest high-energy neutrino spot, NGC 1068 has received much attention in recent years. Here we focus on the central region of the active galactic nuclei (AGN) and propose an outflow-cloud interaction model that could probably explain the observed neutrino data. Considering the accretion process adjacent to the central supermassive black hole (SMBH) of NGC 1068, strong outflows will be generated, which will likely interact with surrounding clouds floating in the corona region. Particles carried by the outflow will be accelerated to very high energy by the shocks forming during the outflow-cloud interactions. For the accelerated high-energy protons, $p\gamma$ interactions with the background photon field of the corona and disk and $pp$ interaction with the surrounding gas will produce considerable high-energy $\gamma$-rays and neutrino. However, because of the extremely dense photon fields in the corona and disk, the newly generated $\gamma$-rays will be significantly attenuated through the $\gamma\gamma$ absorptions. In our scenario, the expected GeV-TeV $\gamma$-ray emission will be suppressed to a much lower level than the neutrino emission, consistent with the observational characteristics of NGC 1068, while the generated 1-30,TeV neutrino flux can fit the IceCube data very well.

Evidence for bipolar explosions in Type IIP supernovae

• Authors: T. Nagao, K. Maeda, S. Mattila, H. Kuncarayakti, M. Kawabata, K. Taguchi, T. Nakaoka, A. Cikota, M. Bulla, S. Vasylyev, C. P. Gutierrez, M. Yamanaka, K. Isogai, K. Uno, M. Ogawa, S. Inutsuka, M. Tsurumi, R. Imazawa, K.S. Kawabata

• Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2406.14057

• Pdf link: https://arxiv.org/pdf/2406.14057

• Abstract Recent observations of core-collapse supernovae (SNe) suggest aspherical explosions. Globally aspherical structures in SN explosions are regarded as the key for understanding their explosion mechanism. However, the exact explosion geometries from the inner cores to the outer envelopes are poorly understood. Here, we present photometric, spectroscopic and polarimetric observations of the Type IIP SN 2021yja and discuss its explosion geometry, in comparison to those of other Type IIP SNe that show large-scale aspherical structures in their hydrogen envelopes (SNe 2012aw, 2013ej and 2017gmr). During the plateau phase, SNe 2012aw and 2021yja exhibit high continuum polarization characterized by two components with perpendicular polarization angles. This behavior can be interpreted to be due to a bipolar explosion, composed of a polar (energetic) and an equatorial (bulk) components of the SN ejecta. In such a bipolar explosion, an aspherical axis created by the polar ejecta would be dominating at early phases, while the perpendicular axis along the equatorial ejecta would emerge at late phases after the receding of the photosphere in the polar ejecta. The interpretation of the bipolar explosions in SNe 2012aw and 2021yja is also supported by other observational properties, including the time evolution of the line velocities and the line shapes in the nebular spectra. The polarization of other Type IIP SNe that show large-scale aspherical structures in the hydrogen envelope (SNe 2013ej and 2017gmr) is also consistent with the bipolar-explosion scenario, although this is not conclusive.

High-resolution observations of two pores with the integral field unit (IFU) of the GREGOR Infrared Spectrograph (GRIS)

• Authors: Meetu Verma

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2406.14298

• Pdf link: https://arxiv.org/pdf/2406.14298

• Abstract The goal is to compare the intricate details of the magnetic and flow fields around two solar pores, where one is part of an active region and the other is an isolated pore, with a secondary goal of demonstrating the scientific capabilities of the GRIS IFU. Two pores were observed with the HiFI and the GRIS IFU at the GREGOR solar telescope on 29 May and 6 June 2019. The GRIS IFU mosaics provide spectropolarimetric data for inversions of the Ca I 1083.9 nm and Si I 1082.7 nm spectral lines, covering the deep and upper photosphere. The t-SNE machine learning algorithm is employed to identify different classes of Si I Stokes-V profiles. The LCT technique derives horizontal proper motions around the pores. Both pores contain a thin light bridge, are stable during the observations, and never develop a penumbra. The isolated pore is three times smaller and significantly darker than the active-region pore, which is not predicted by simulations. The LCT maps show inflows around both pores, with lower velocities for the isolated pore. Both pores are embedded in the photospheric LOS velocity pattern of the granulation but filamentary structures are only visible in the chromospheric LOS maps of the active-region pore. The t-SNE identifies five clusters of Si I Stokes-V profiles, revealing an `onion-peel' magnetic field structure, despite the small size of the pores. The core with strong vertical magnetic fields is surrounded by concentric layers with lower and more inclined magnetic fields. The active-region pore shows some signatures of increased interaction between plasma motions and magnetic fields, which can be considered as early signs of penumbra formation. However, similar physical properties prevail for smaller pores. A statistically meaningful sample of different pore sizes and morphologies is required to distinguish between active-region and isolated pore formation mechanisms.

Analysis of Differences between ICME catalogues and Construction of a Unified Catalogue

• Authors: Anton Shiryaev (1 and 2), Ksenia Kaportseva (1 and 3) ((1) Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, (2) Faculty of Information Technology, Bryansk State Technical University, (3) Lomonosov Moscow State University, Physics Faculty)

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

• Arxiv link: https://arxiv.org/abs/2406.14363

• Pdf link: https://arxiv.org/pdf/2406.14363

• Abstract Multiple magnetic and kinetic solar wind plasma parameters are used to detect coronal mass ejections (CMEs) as they travel through the heliosphere. There are various interplanetary CME (ICME) catalogues, but due to differences between their ICME identification criteria they can significantly vary. In this paper we analyze Richardson and Cane and CCMC CME Scoreboard ICME catalogues and the SRI RAS solar wind types catalogue, and propose an algorithm of merging them. A unified catalogue is constructed for 2010 to 2022. The resulting catalogue is completed with data from the OMNI database. Analysis of the unified catalogue demonstrated high accuracy when merging events present in multiple catalogues and a tendency of events defined in all three initial catalogues to demonstrate greater duration, speed and geoeffectiveness. The catalog is presented on the SINP MSU Space Weather Exchange website: this https URL

A disc wind origin for the optical spectra of dwarf novae in outburst

• Authors: Yusuke Tampo, Christian Knigge, Knox S. Long, James H. Matthews, Noel Castro Segura

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)

• Arxiv link: https://arxiv.org/abs/2406.14396

• Pdf link: https://arxiv.org/pdf/2406.14396

• Abstract Many high-state cataclysmic variables (CVs) exhibit blue-shifted absorption features in their ultraviolet (UV) spectra -- a smoking-gun signature of outflows. However, the impact of these outflows on {\em optical} spectra remains much more uncertain. During its recent outburst, the eclipsing dwarf nova V455 And displayed strong optical emission lines whose cores were narrower than expected from a Keplerian disc. Here, we explore whether disc + wind models developed for matching UV observations of CVs can also account for these optical spectra. Importantly, V455And was extremely bright at outburst maximum: the accretion rate implied by fitting the optical continuum with a standard disc model is $\dot{M}_{\rm acc} \simeq 10^{-7}{\rm M}\odot~{\rm yr^{-1}}$. Allowing for continuum reprocessing in the outflow helps to relax this constraint. A disk wind can also broadly reproduce the optical emission lines, but only if the wind is (i) highly mass-loaded, with a mass-loss rate reaching $\dot{M}{\rm wind} \simeq 0.4 \dot{M}{\rm acc}$, and/or (ii) clumpy, with a volume filling factor $f_V \simeq 0.1$. The same models can describe the spectral evolution across the outburst, simply by lowering $\dot{M}{\rm acc}$ and $\dot{M}_{\rm wind}$. Extending these models to lower inclinations and into the UV produces spectra consistent with those observed in face-on high-state CVs. We also find, for the first time in simulations of this type, P-Cygni-like absorption features in the Balmer series, as have been observed in both CVs and X-ray binaries. Overall, dense disc winds provide a promising framework for explaining multiple observational signatures seen in high-state CVs, but theoretical challenges persist.

Merger seismology: distinguishing massive merger products from genuine single stars using asteroseismology

• Authors: Jan Henneco, Fabian R. N. Schneider, Saskia Hekker, Conny Aerts

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2406.14416

• Pdf link: https://arxiv.org/pdf/2406.14416

• Abstract Products of stellar mergers are predicted to be common in stellar populations and can potentially explain stars with peculiar properties. When the merger occurs after the initially more massive star has evolved into the Hertzsprung gap (HG), the merger product may remain in the blue part of the Hertzsprung-Russell diagram (HRD) for millions of years. Such objects could, therefore, explain the overabundance of observed blue stars, such as blue supergiants. However, it is currently not straightforward to distinguish merger products from genuine single stars. We make detailed asteroseismic comparisons between models of massive post-main-sequence merger products and genuine single stars to identify which asteroseismic diagnostics can be used to distinguish them. In doing so, we develop tools for the relatively young field of merger seismology. Genuine single stars in the HG are fully radiative, while merger products have a convective He-burning core and convective H-burning shell while occupying similar locations in the HRD. These structural differences are reflected in lower asymptotic period spacing values for merger products and the appearance of deep dips in their period spacing patterns. Our genuine single-star models with masses above roughly 11.4 solar masses develop short-lived intermediate convective zones during their HG evolution. This also leads to deep dips in their period spacing patterns. Because of the lack of a convective core, merger products and genuine single stars can be distinguished based on their asymptotic period spacing value in this mass range. We perform the comparisons with and without the effects of slow rotation included in the pulsation equations and conclude that the two types of stars are seismically distinguishable in both cases. The observability of the distinguishing asteroseismic features of merger products can now be assessed and exploited in practice.

A More Precise Measurement of the Radius of PSR J0740+6620 Using Updated NICER Data

• Authors: Alexander J. Dittmann, M. Coleman Miller, Frederick K. Lamb, Isiah Holt, Cecilia Chirenti, Michael T. Wolff, Slavko Bogdanov, Sebastien Guillot, Wynn C. G. Ho, Sharon M. Morsink, Zaven Arzoumanian, Keith C. Gendreau

• Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

• Arxiv link: https://arxiv.org/abs/2406.14467

• Pdf link: https://arxiv.org/pdf/2406.14467

• Abstract PSR J0740+6620 is the neutron star with the highest precisely determined mass, inferred from radio observations to be $2.08\pm0.07,\rm M_\odot$. Measurements of its radius therefore hold promise to constrain the properties of the cold, catalyzed, high-density matter in neutron star cores. Previously, Miller et al. (2021) and Riley et al. (2021) reported measurements of the radius of PSR J0740+6620 based on Neutron Star Interior Composition Explorer (NICER) observations accumulated through 17 April 2020, and an exploratory analysis utilizing NICER background estimates and a data set accumulated through 28 December 2021 was presented in Salmi et al. (2022). Here we report an updated radius measurement, derived by fitting models of X-ray emission from the neutron star surface to NICER data accumulated through 21 April 2022, totaling $\sim1.1$ Ms additional exposure compared to the data set analyzed in Miller et al. (2021) and Riley et al. (2021), and to data from X-ray Multi-Mirror (XMM-Newton) observations. We find that the equatorial circumferential radius of PSR J0740+6620 is $12.92_{-1.13}^{+2.09}$ km (68% credibility), a fractional uncertainty $\sim83%$ the width of that reported in Miller et al. (2021), in line with statistical expectations given the additional data. If we were to require the radius to be less than 16 km, as was done in Salmi et al. (2024), then our 68% credible region would become $R=12.76^{+1.49}_{-1.02}$ km, which is close to the headline result of Salmi et al. (2024). Our updated measurements, along with other laboratory and astrophysical constraints, imply a slightly softer equation of state than that inferred from our previous measurements.

$\texttt{cunuSHT}$: GPU Accelerated Spherical Harmonic Transforms on Arbitrary Pixelizations

• Authors: Sebastian Belkner, Adriaan J. Duivenvoorden, Julien Carron, Nathanael Schaeffer, Martin Reinecke

• Subjects: Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

• Arxiv link: https://arxiv.org/abs/2406.14542

• Pdf link: https://arxiv.org/pdf/2406.14542

• Abstract We present $\texttt{cunusht}$, a general-purpose Python package that wraps a highly efficient CUDA implementation of the nonuniform spin-$0$ spherical harmonic transform. The method is applicable to arbitrary pixelization schemes, including schemes constructed from equally-spaced iso-latitude rings as well as completely nonuniform ones. The algorithm has an asymptotic scaling of $\mathrm{O}{(\ell_{\rm max}^3)}$ for maximum multipole $\ell_{\rm max}$ and achieves machine precision accuracy. While $\texttt{cunusht}$ is developed for applications in cosmology in mind, it is applicable to various other interpolation problems on the sphere. We outperform the fastest available CPU algorithm by a factor of up to 5 for problems with a nonuniform pixelization and $\ell_{\rm max}>4\cdot10^3$ when comparing a single modern GPU to a modern 32-core CPU. This performance is achieved by utilizing the double Fourier sphere method in combination with the nonuniform fast Fourier transform and by avoiding transfers between the host and device. For scenarios without GPU availability, $\texttt{cunusht}$ wraps existing CPU libraries. $\texttt{cunusht}$ is publicly available and includes tests, documentation, and demonstrations.

by olozhika (Xing Yuchen).

2024-06-21