RAS_WEB (Page 3)

Age analysis of extrasolar planets: Insight from stellar isochrone models C. Swastik, Ravinder K. Banyal, Mayank Narang, Athira Unni, T. Sivarani arXiv:2404.13398v1 Announce Type: new Abstract: There is growing evidence from stellar kinematics and galactic chemical evolution (GCE) suggesting that giant planets (M$_{P}geq$0.3$M_{J}$) are relatively young compared to the most commonly occurring population of small planets (M$_{P} $10 days), implying that hot Jupiters could be the youngest systems to emerge in the progression of planet formation.arXiv:2404.13398v1 Announce Type: new Abstract: There is growing evidence from stellar kinematics and galactic chemical evolution (GCE) suggesting that giant planets (M$_{P}geq$0.3$M_{J}$) are relatively young compared to the most commonlyRead More →

Stellar Abundances at the Center of Early Type Galaxies with Fine Structure Nicholas Barth, George C. Privon, Rana Ezzeddine, Aaron S. Evans, Ezequiel Treister arXiv:2404.13459v1 Announce Type: new Abstract: Our understanding of early-type galaxies (ETGs) has grown in the past decade with the advance of full-spectrum fitting techniques used to infer the properties of the stellar populations that make-up the galaxy. We present ages, central velocity dispersions, and abundance ratios relative to Fe of C, N, O, Mg, Si, Ca, Ti, Cr, Mn, Co, Ni, Cu, Sr, Ba, and Eu, derived using full-spectrum fitting techniques for three ETGs NGC 2865, NGC 3818, and NGC 4915.Read More →

Galactic Superbubbles in 3D: Wind Formation and Cloud Shielding Osmer Su’arez-L’opez, Andr’es S. Villares, Wladimir E. Banda-Barrag’an arXiv:2404.13498v1 Announce Type: new Abstract: Galactic superbubbles are triggered by stellar feedback in the discs of star-forming galaxies. They are important in launching galactic winds, which play a key role in regulating the mass and energy exchange in galaxies. Observations can only reveal projected information and the 3D structure of such winds is quite complex. Therefore, numerical simulations are required to further our understanding of such structures. Here, we describe hydrodynamical simulations targeting two spatial scales. Large-scale superbubble models reveal supernova-driven outflows, and their subsequent merging, which leadsRead More →

An ALMA search for substructure and fragmentation in starless cores in Orion B North Samuel Fielder, Helen Kirk, Michael Dunham, Stella Offner arXiv:2404.13520v1 Announce Type: new Abstract: We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of 73 starless and protostellar cores in the Orion B North molecular cloud. We detect a total of 34 continuum sources at 106 GHz, and after comparisons with other data, 4 of these sources appear to be starless. Three of the four sources are located near groupings of protostellar sources, while one source is an isolated detection. We use synthetic observations of a simulation modeling a collapsing turbulent,Read More →

Is climate variability the result of frequency modulation by the solar cycle? Evidence from the El Nino Southern Oscillation, Australian climate, Central England Temperature, and reconstructed solar activity and climate records Ian R. Edmonds arXiv:2404.13542v1 Announce Type: new Abstract: Oceanic atmospheric oscillations and climate variability are tightly linked and both exhibit broad band spectral content that ranges, with roughly equal strength, from annual to centennial periodicity. The explanation for variability based on the integration of weather noise leads to a spectral content heavily weighted to low frequencies; explaining the variability as resulting from solar forcing leads to a narrow band, approximately eleven year period, spectralRead More →

The Impact of Tidal Migration of Hot Jupiters on the Rotation of Sun-like Main-sequence Stars Shuai-Shuai Guo arXiv:2404.13548v1 Announce Type: new Abstract: The tidal interactions of planets affect the stellar evolutionary status and the constraint of their physical parameters by gyrochronology. In this work, we incorporate the tidal interaction and magnetic braking of the stellar wind into MESA and calculate a large grid of 25000 models, covering planets with masses of 0.1-13.0$,$$M_{mathrm{J}}$ with different orbital distances that orbit late-type stars of different metallicities. We also explore the effect of different stellar initial rotations on the tidal interactions. Our results show that in the case ofRead More →

The relationship of SMBHs and host galaxies at $zRead More →

New Evidence of Binarity in Young {alpha}-Rich Turn-off and Subgiant Stars: Fast Rotation and Strong Magnetic Activity Jie Yu, Luca Casagrande, Ioana Ciucu{a}, Yuan-Sen Ting, Simon J. Murphy, Boquan Chen arXiv:2404.13562v1 Announce Type: new Abstract: Young {alpha}-rich (YAR) stars within the old Galactic thick disk exhibit a dual characteristic of relative youth determined with asteroseismology and abundance enhancement in {alpha} elements measured from high-resolution spectroscopy. The youth origin of YAR stars has been proposed to be binary evolution via mass transfer or stellar mergers. If that is the case, YAR stars should spin rapidly and thus be magnetically active, because they are mass and angularRead More →

ALMA 2D Super-resolution Imaging of Taurus-Auriga Protoplanetary Disks: Probing Statistical Properties of Disk Substructures Masayuki Yamaguchi, Takayuki Muto, Takashi Tsukagoshi, Hideko Nomura, Naomi Hirano, Takeshi Nakazato, Shiro Ikeda, Motohide Tamura, Ryohei Kawabe arXiv:2404.13570v1 Announce Type: new Abstract: In the past decade, ALMA observations of protoplanetary disks revealed various substructures including gaps and rings. Their origin may be probed through statistical studies on the physical properties of the substructures. We present the analyses of archival ALMA Band 6 continuum data of 43 disks (39 Class II and 4 Herbig Ae) in the Taurus-Auriga region. We employ a novel 2D super-resolution imaging technique based on sparse modelingRead More →

The PEPSI Exoplanet Transit Survey (PETS). V: New Na D transmission spectra indicate a quieter atmosphere on HD 189733b E. Keles, S. Czesla, K. Poppenhaeger, P. Hauschildt, T. A. Carroll, I. Ilyin, M. Baratella, M. Steffen, K. G. Strassmeier, A. S. Bonomo, B. S. Gaudi, T. Henning, M. C. Johnson, K. Molaverdikhani, V. Nascimbeni, J. Patience, A. Reiners, G. Scandariato, E. Schlawin, E. Shkolnik, D. Sicilia, A. Sozzetti, M. Mallonn, C. Veillet, J. Wang, F. Yan arXiv:2404.13586v1 Announce Type: new Abstract: Absorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds. We present a new high-resolution transit time-seriesRead More →

New galaxy UV luminosity constraints on warm dark matter from JWST Bin Liu, Huanyuan Shan, Jiajun Zhang arXiv:2404.13596v1 Announce Type: new Abstract: We exploit the recent {it James Webb Space Telescope} (JWST) determination of galaxy UV luminosity functions over the redshift range $z=9-14.5$ to derive constraints on warm dark matter (WDM) models. The delayed structure formation in WDM universe makes high redshift observations to be a powerful probe to set limits on the particle mass $m_mathrm{x}$ of WDM candidates. By integrating these observations with blank-field surveys conducted by {it Hubble Space Telescope} (HST) at redshifts $z=4-8$, we impose constraints on both astrophysical and WDM parametersRead More →

The Lockman–SpReSO project. Main properties of infrared selected star-forming galaxies Mauro Gonz’alez-Otero, Jordi Cepa, Carmen P. Padilla-Torres, Maritza A. Lara-L’opez, J. Jes’us Gonz’alez, ‘Angel Bongiovanni, Bernab’e Cedr’es, Miguel Cervi~no, Irene Cruz-Gonz’alez, Mauricio El’ias-Ch’avez, Mart’in Herrera-Edoqui, H’ector J. Ibarra-Medel, Yair Krongold, Jakub Nadolny, C. Alenka Negrete, Ana Mar’ia P’erez Garc’ia, Jos’e A. De Diego, J. Ignacio Gonz’alez-Serrano, H’ector Hern’andez-Toledo, Ricardo P’erez-Mart’inez, Miguel S’anchez-Portal arXiv:2404.13629v1 Announce Type: new Abstract: Methods.We applied distinct selection criteria to attain an SFG sample with minimal AGN contamination. Multiple approaches were used to estimate the intrinsic extinction, SFR and gas-phase metallicity for the SFGs. In conjunction with findings in the literature, weRead More →

Rapid Optical Flare in the Extreme TeV Blazar 1ES 0229+200 on Intraday Timescale with TESS Shubham Kishore, Alok C. Gupta, Paul J. Wiita, S. N. Tiwari arXiv:2404.13638v1 Announce Type: new Abstract: The extreme TeV blazar 1ES 0229+200 is a high-frequency-peaked BL Lacertae object. It has not shown intraday variability in extensive optical and X-ray observations. Nor has it shown any significant variability on any measurable timescale in the 1-100 GeV energy range over a 14-year span, but variations in the source flux around its average are present in the energy range above 200 GeV. We searched for intraday optical variability in 1ES 0229+200 as partRead More →

A short review of the pulsar magnetic inclination angles (II) Biao-Peng Li, Wen-Qi Ma, Zhi-Fu Gao arXiv:2404.13700v1 Announce Type: new Abstract: The pulsar magnetic inclination angle is a key parameter for pulsar physics. It influences the observable properties of pulsars, such as the pulse beam width, braking index, polarisation, and emission geometry. In this study, we give a brief overview of the current state of knowledge and research on this parameter and its implications for the internal physics of pulsars. We use the observed pulsar data of magnetic inclination angle and braking index to constrain the star’s number of precession cycles, $xi$, which reflects theRead More →

Learning Galaxy Intrinsic Alignment Correlations Sneh Pandya, Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek, Robin Walters arXiv:2404.13702v1 Announce Type: new Abstract: The intrinsic alignments (IA) of galaxies, regarded as a contaminant in weak lensing analyses, represents the correlation of galaxy shapes due to gravitational tidal interactions and galaxy formation processes. As such, understanding IA is paramount for accurate cosmological inferences from weak lensing surveys; however, one limitation to our understanding and mitigation of IA is expensive simulation-based modeling. In this work, we present a deep learning approach to emulate galaxy position-position ($xi$), position-orientation ($omega$), and orientation-orientation ($eta$) correlation function measurements and uncertainties from halo occupationRead More →

Empirical stability criteria for 3D hierarchical triple systems I: Circumbinary planets Nikolaos Georgakarakos, Siegfried Eggl, Mohamad Ali-Dip, Ian Dobbs-Dixon arXiv:2404.13746v1 Announce Type: new Abstract: In this work we revisit the problem of the dynamical stability of hierarchical triple systems with applications to circumbinary planetary orbits. We carry out more than 3 10^8 numerical simulations of planets between the size of Mercury and the lower fusion boundary (13 Jupiter masses) which revolve around the center of mass of a stellar binary over long timescales. For the first time, three dimensional and eccentric planetary orbits are considered. We explore systems with a variety of binary and planetaryRead More →

TOI-837b is a Young Saturn-sized Exoplanet with a Massive 70 $M_{oplus}$ Core Oscar Barrag’an, Haochuan Yu, Alix Violet Freckelton, Annabella Meech, Michael Cretignier, Annelies Mortier, Suzanne Aigrain, Baptiste Klein, Niamh K. O’Sullivan, Edward Gillen, Louise Dyregaard Nielsen, Manuel Mallorqu’in, Norbert Zicher arXiv:2404.13750v1 Announce Type: new Abstract: We present an exhaustive photometric and spectroscopic analysis of TOI-837, a F9/G0 35 Myr young star, hosting a transiting exoplanet, TOI-837b, with an orbital period of 8.32d. Utilising data from TESS and ground-based observations, we determine a planetary radius of 0.82 R_J for TOI-837b. Through detailed HARPS spectroscopic time series analysis, we derive a Doppler semi-amplitude of 36 m/s,Read More →

Exact CMB B-mode power spectrum from anisotropic cosmic birefringence Toshiya Namikawa arXiv:2404.13771v1 Announce Type: new Abstract: We calculate the cosmic microwave background (CMB) $B$-mode power spectrum resulting from anisotropic cosmic birefringence, without relying on the thin approximation of the last scattering surface. Specifically, we consider the influence of anisotropic cosmic birefringence arising from massless axion-like particles. Comparing our results to those obtained using the thin approximation, we observe a suppression in the amplitude of the $B$-mode power spectrum by approximately an order of magnitude at large angular scales ($ell lesssim 10$) and by a factor of two at small angular scales ($ell gtrsim 100$) whenRead More →

A Cyclic Spectroscopy Scintillation Study of PSR B1937+21 I. Demonstration of Improved Scintillometry Jacob E. Turner, Timothy Dolch, James M. Cordes, Stella K. Ocker, Daniel R. Stinebring, Shami Chatterjee, Maura A. McLaughlin, Victoria E. Catlett, Cody Jessup, Nathaniel Jones, Christopher Scheithauer arXiv:2404.13796v1 Announce Type: new Abstract: We use cyclic spectroscopy to perform high frequency-resolution analyses of multi-hour baseband Arecibo observations of the millisecond pulsar PSR B1937+21. This technique allows for the examination of scintillation features in far greater detail than is otherwise possible under most pulsar timing array observing setups. We measure scintillation bandwidths and timescales in each of eight subbands across a 200 MHzRead More →

Discovery of the Free Precession in the Magnetar SGR 1806$-$20 with the ASCA GIS Kazuo Makishima, Nagomi Uchida, Teruaki Enoto arXiv:2404.13799v1 Announce Type: new Abstract: Four X-ray data sets of the Soft Gamma Repeater SGR 1806-20, taken with the Gas Imaging Spectrometer (GIS) onboad ASCA, were analyzed. Three of them were acquired over 1993 October 9-20, whereas the last one in 1995 October. Epoch-folding analysis of the 2.8-12 keV signals confirmed the $sim 7.6$ s pulses in these data, which Kouveliotou et al. (1998) reported as one of the earliest pulse detections from this object. In the 1995 observation, 3-12 keV pulses were phase modulatedRead More →