August 2024 (Page 3)

Unveiling the chemical fingerprint of phosphorus-rich stars II. Heavy-element abundances from UVES/VLT spectra Maren Brauner, Marco Pignatari, Thomas Masseron, D. A. Garc’ia-Hern’andez, Maria Lugaro arXiv:2408.12938v1 Announce Type: new Abstract: The atmospheres of phosphorus-rich stars have been shown to contain between 10 and 100 times more P than our Sun. Given its crucial role as an essential element for life, it is especially necessary to uncover the origin of P-rich stars to gain insights into the still unknown nucleosynthetic formation pathways of P in our Galaxy. Our objective is to obtain the extensive chemical abundance inventory of four P-rich stars, covering a large range of heavyRead More →

An Analytic Model of Gravitational Collapse Induced by Radiative Cooling: Instability Scale, Infall Velocity, and Accretion Rate James Gurian, Boyuan Liu, Donghui Jeong, Takashi Hosokawa, Shingo Hirano, Naoki Yoshida arXiv:2408.12940v1 Announce Type: new Abstract: We present an analytic description of the spherically symmetric gravitational collapse of radiatively cooling gas clouds. The approach is based on developing the “one-zone” density-temperature relationship of the gas into a full dynamical model. We convert this density-temperature relationship into a barotropic equation of state, which we use to calculate the density and velocity profiles of the gas. From these quantities we calculate the time-dependent mass accretion rate onto the centerRead More →

Rediscussion of eclipsing binaries. Paper XX. HO Tel checkout John Southworth arXiv:2408.12955v1 Announce Type: new Abstract: We present a detailed analysis of the detached eclipsing binary system HO Telescopii, which contains two A-type stars in a circular orbit of period 1.613 d. We use light curves from the Transiting Exoplanet Survey Satellite (TESS), which observed HO Tel in three sectors, to determine its photometric properties and a precise orbital ephemeris. We augment these results with radial velocity measurements from Surgit et al. to determine the masses and radii of the component stars: M_A = 1.906 +/- 0.031 Msun, M_B = 1.751 +/- 0.034 Msun, R_ARead More →

Peering into the Heart of the Giant Molecular Cloud G148.24+00.41: A Deep Near-infrared View of the Newly Hatched Cluster FSR 655 Vineet Rawat (Physical Research Laboratory, Ahmedabad, India, Indian Institute of Technology Gandhinagar, India), M. R. Samal (Physical Research Laboratory, Ahmedabad, India), D. K. Ojha (Tata Institute of Fundamental Research, Mumbai, India), Brajesh Kumar (South-Western Institute for Astronomy Research, Yunnan University, People’s Republic of China, Aryabhatta Research Institute of Observational Sciences, Nainital, India), Saurabh Sharma (Aryabhatta Research Institute of Observational Sciences, Nainital, India), J. Jose (Indian Institute of Science Education and Research), Ram Sagar (Indian Institute of Astrophysics, Bangalore, India, and), R. K. Yadav (NationalRead More →

M giants with IGRINS IV. Identification and characterization of a near-IR line of the s-element Barium G. Nandakumar, N. Ryde, H. Hartman, G. Mace arXiv:2408.12971v1 Announce Type: new Abstract: Neutron-capture elements represent an important nucleosynthetic channel in the study of the Galactic Chemical Evolution of stellar populations. For stellar populations behind significant extinction, such as those in the Galactic Center and along the Galactic plane, abundance analyses based on near-IR spectra are necessary. Previously, spectral lines from the neutron-capture elements such as copper (Cu), cerium (Ce), neodymium (Nd), and ytterbium (Yb) have been identified in the H band, while yttrium (Y) lines have been identifiedRead More →

The UK Submillimetre and Millimetre Astronomy Roadmap 2024 K. Pattle, P. S. Barry, A. W. Blain, M. Booth, R. A. Booth, D. L. Clements, M. J. Currie, D. Eden, G. A. Fuller, M. Griffin, P. G. Huggard, J. D. Ilee, J. Karoly, Z. A. Khan, N. Klimovich, E. Kontar, P. Klaassen, A. J. Rigby, P. Scicluna, S. Serjeant, B. -K. Tan, D. Ward-Thompson, T. G. Williams, T. A. Davis, J. Greaves, R. Ivison, J. Marin, M. Matsuura, J. M. C. Rawlings, A. Saintonge, G. Savini, M. W. L. Smith, D. J. Taylor arXiv:2408.12975v1 Announce Type: new Abstract: In this Roadmap, we present a vision forRead More →

Checking the Empirical Relations with the Current Localized Fast Radio Bursts Lin-Yu Li, Jing-Yi Jia, Da-Chun Qiang, Hao Wei arXiv:2408.12983v1 Announce Type: new Abstract: Although fast radio bursts (FRBs) were discovered more than a decade ago, and they have been one of the active fields in astronomy and cosmology, their origins are still unknown. An interesting topic closely related to the origins of FRBs is their classifications. On the other hand, FRBs are actually a promising probe to study cosmology. In the literature, some new classifications of FRBs different from repeaters and non-repeaters were suggested, and some tight empirical relations have been found for them.Read More →

Detection of a Transient Quasi-periodic Oscillation in $gamma$-Rays from Blazar PKS 2255-282 Ajay Sharma, Anuvab Banerjee, Avik Kumar Das, Avijit Mandal, Debanjan Bose arXiv:2408.13052v1 Announce Type: new Abstract: We conducted a comprehensive variability analysis of the blazar PKS 2255-282 using Fermi-LAT observations spanning over four years, from MJD 57783.5 to 59358.5. Our analysis revealed a transient quasi-periodic oscillation (QPO) with a period of 93$pm$2.6 days. We employed a variety of Fourier-based methods, including the Lomb-Scargle Periodogram (LSP) and Weighted Wavelet Z-Transform (WWZ), as well as time domain analysis techniques such as Seasonal and Non-Seasonal Autoregressive Integrated Moving Average (ARIMA) models and the Stochastic modeling withRead More →

Photofragmentation of Corannulene (C20H10) and Sumanene (C21H12) cations in gas phase and its Astrophysical implications P. Sundararajan, A. Candian, J. Kamer, H. Linnartz, A. G. G. M. Tielens arXiv:2408.13072v1 Announce Type: new Abstract: The aromatic infrared Bands (AIBs) dominate the mid-infrared spectra of many galactic and extragalactic sources. These AIBs are generally attributed to fluorescent emission from aromatic molecules. Unified efforts from experimentalists and theoreticians to assign these AIB features have recently gotten additional impetus with the launch of the James Webb Space Telescope (JWST) as the Mid-InfraRed Instrument (MIRI) delivers mid-IR spectrum with greatly increased sensitivity and spectral resolution. PAHs in space can existRead More →

The rates and host galaxies of pair-instability supernovae through cosmic time: Predictions from BPASS and IllustrisTNG Max M. Briel, Benjamin Metha, Jan J. Eldridge, Takashi J. Moriya, Michele Trenti arXiv:2408.13076v1 Announce Type: new Abstract: Pair-instability supernovae (PISNe) have long been predicted to be the final fates of near-zero-metallicity very massive stars ($Z arXiv:2408.13076v1 Announce Type: new Abstract: Pair-instability supernovae (PISNe) have long been predicted to be the final fates of near-zero-metallicity very massive stars ($ZRead More →

The Radio Spectra of High Luminosity Compact Symmetric Objects (CSO-2s): Implications for Studies of Compact Jetted Active Galactic Nuclei P. V. de la Parra, A. C. S Readhead, T. Herbig, S. Kiehlmann, M. L. Lister, V. Pavlidou, R. A. Reeves, A. Siemiginowska, A. G. Sullivan, T. Surti, A. Synani, K. Tassis, G. B. Taylor, P. N. Wilkinson, M. F. Aller, R. D. Blandford, N. Globus, C. R. Lawrence, B. Molina, S. O’Neill, T. J. Pearson arXiv:2408.13077v1 Announce Type: new Abstract: This paper addresses, for the first time, a key aspect of the phenomenology of Compact Symmetric Objects (CSOs) — the characteristics of their radio spectra.Read More →

The solar beryllium abundance revisited with 3D non-LTE models A. M. Amarsi, D. Ogneva, G. Buldgen, N. Grevesse, Y. Zhou, P. S. Barklem arXiv:2408.13105v1 Announce Type: new Abstract: The present-day abundance of beryllium in the solar atmosphere provides clues about mixing mechanisms within stellar interiors. However, abundance determinations based on the Be II 313.107 nm line are prone to systematic errors due to imperfect model spectra. These errors arise from missing continuous opacity in the UV, a significant unidentified blend at 313.102 nm, departures from local thermodynamic equilibrium (LTE), and microturbulence and macroturbulence fudge parameters associated with one-dimensional (1D) hydrostatic model atmospheres. Although these factorsRead More →

The Hubble parameter of the Local Distance Ladder from dynamical dark energy with no free parameters Maurice H. P. M. van Putten arXiv:2408.13121v1 Announce Type: new Abstract: Our cosmology contains Big Bang relic fluctuations by a loss of time-translation symmetry on a Hubble time scale. The contribution to the vacuum is identified with dynamical dark energy $Lambdasimeq alpha_pLambda_0$ by an IR coupling $alpha_psim hbar$ of the bare cosmological constant $Lambda_0simhbar^{-1}$ consistent with general relativity, where $hbar$ is the Planck constant. Described by the trace $J=(1-q)H^2$ of the Schouten tensor derived from a path integral formulation with gauged global phase, the proposed $J$CDM takes us beyondRead More →

Laser-induced fragmentation of coronene cations S. Panchagnula, J. Kamer, A. Candian, H. R. Hrodmarsson, H. Linnartz, J. Bouwman, A. G. G. M. Tielens arXiv:2408.13141v1 Announce Type: new Abstract: Polycyclic aromatic hydrocarbons are an important component of the interstellar medium of galaxies and photochemistry plays a key role in the evolution of these species in space. Here, we explore the photofragmentation behaviour of the coronene cation (C24H12+) using time of flight mass spectrometry. The experiments show photodissociation fragmentation channels including the formation of bare carbon clusters (Cn+) and hydrocarbon chains (CnHx+). The mass spectrum of coronene is dominated by peaks from C11+ and C7H+. Density functionalRead More →

Constraining binary mergers in AGN disks using the non-observation of lensed gravitational waves Samson H. W. Leong, Justin Janquart, Aditya Kumar Sharma, Paul Martens, Parameswaran Ajith, Otto A. Hannuksela arXiv:2408.13144v1 Announce Type: new Abstract: The dense and dynamic environments within active galactic nuclei (AGN) accretion disks may serve as prolific birthplaces for binary black holes (BBHs) and one possible origin for some of the BBHs detected by gravitational-wave (GW) observatories. We show that a considerable fraction of the BBH in AGN disks will be strongly lensed by the central supermassive black hole (SMBH). Thus, the non-observation of lensed GW signals can be used to constrainRead More →

Generating ultra-compact neutron stars with bosonic dark matter Sarah Louisa Pitz, J"urgen Schaffner-Bielich arXiv:2408.13157v1 Announce Type: new Abstract: In this work we investigate the properties of neutron stars admixed with selfinteracting scalar bosonic dark matter. The dark matter interaction is described by a generalized $phi^n$ power-law potential. We perform a stability analysis of these two-fluid objects by studying the onset of the unstable radial modes. We find ultra-compact neutron star-dark matter configurations where the neutron star matter is confined to a core radius of values below $7$ km which is unreachable for pure neutron stars. The total gravitational maximum mass of these ultra-compact configurations canRead More →

Impact of HI cooling and study of accretion disks in AGB wind-companion smoothed particle hydrodynamic simulations Jolien Malfait, Lionel Siess, Mats Esseldeurs, Sofia H. J. Wallstr"om, Alex de Koter, Leen Decin arXiv:2408.13158v1 Announce Type: new Abstract: High-resolution observations reveal that the outflows of evolved low- and intermediate-mass stars harbour complex morphological structures that are linked to the presence of one or multiple companions. Hydrodynamical simulations provide a way to study the impact of a companion on the shaping of the AGB outflow. Using smoothed particle hydrodynamic (SPH) simulations of a mass losing AGB star with a binary companion, we study the impact of including HIRead More →

Butterfly Diagram and Other Properties of Plage Areas from Kodaikanal Ca II K Photographs Covering 1904-2007 Bibhuti Kumar Jha, Theodosios Chatzistergos, Dipankar Banerjee, Ilaria Ermolli, Natalie A. Krivova, Sami K. Solanki, Aditya Priyadarshi arXiv:2408.13192v1 Announce Type: new Abstract: Ca II K observations of the Sun have a great potential for probing the Sun’s magnetism and activity, as well as for reconstructing solar irradiance. The Kodaikanal Solar Observatory (KoSO) in India, houses one of the most prominent Ca II K archives, spanning from 1904 to 2007, obtained under the same experimental conditions over a century, a feat very few other sites have achieved. However, the KoSORead More →

Polarization Measurement of Gamma-ray Bursts with Fermi-GBM: The Case of GRB 180720B P. Veres, W. Duvall, A. Goldstein, M. S. Briggs, J. E. Grove arXiv:2408.13199v1 Announce Type: new Abstract: To achieve confident non-zero polarization measurements for gamma-ray bursts (GRBs) we need sensitive polarimeters and bright GRBs. Here we report on the polarimetric analysis of the bright GRB 180720B using the Fermi Gamma-ray Burst Monitor (GBM). We rely on the detection of photons that scattered off Earth’s atmosphere and into GBM from this burst. Polarized gamma-rays will exhibit a characteristic pattern when scattering off the atmosphere that differs from an unpolarized beam. We compare the measuredRead More →

Morphology of 137 Fast Radio Bursts down to Microseconds Timescales from The First CHIME/FRB Baseband Catalog Ketan R. Sand, Alice P. Curtin, Daniele Michilli, Victoria M. Kaspi, Emmanuel Fonseca, Kenzie Nimmo, Ziggy Pleunis, Kaitlyn Shin, Mohit Bhardwaj, Charanjot Brar, Matt Dobbs, Gwendolyn Eadie, B. M. Gaensler, Ronniy C. Joseph, Calvin Leung, Robert Main, Kiyoshi W. Masui, Ryan Mckinven, Ayush Pandhi, Aaron B. Pearlman, Masoud Rafiei-Ravandi, Mawson W. Sammons, Kendrick Smith, Ingrid H. Stairs arXiv:2408.13215v1 Announce Type: new Abstract: We present a spectro-temporal analysis of 137 fast radio bursts (FRBs) from the first CHIME/FRB baseband catalog, including 125 one-off bursts and 12 repeat bursts, down toRead More →