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X-Ray Studies of Blazar 1ES 1959+650 Using Swift and XMM-Newton Satellite
Gaur, Haritma; Wani, Kiran; Patil, M. K.
High synchrotron energy peaked blazar 1ES 1959+650 was studied with the Swift and XMM-Newton satellites in a total of 127 observations during the period 2018 June-2020 December. We extensively studied its flux and spectral variability on intraday and long-term timescales. Discrete correlation function analysis between soft and hard X-ray bands ind…
The Cycles of Alpha Centauri: Double Dipping of AB
Ayres, Thomas
In mid-2023, the Sunlike dwarfs of nearby α Centauri (HD 128620 ("A"): G2 V; HD 128621 ("B"): K1 V; hereafter "AB") coincidentally both entered coronal (T ≈ 1-3 MK) low states in their long-term X-ray cycles, as captured by the Chandra Observatory and its High Resolution Camera (HRC-I). The assessment benefited from a sensitivity degradation model…
Forming stars in a dual AGN host: molecular and ionized gas in the nearby, luminous infrared merger, Mrk 266
Robert, Carmelle; Rousseau-Nepton, Laurie; Heckman, Timothy +5 more
We present star formation rates based on cold and ionized gas measurements of Mrk 266 (NGC 5256), a system composed of two colliding gas-rich galaxies, each hosting an active galactic nucleus. Using 12CO (1-0) observations with the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), we find a total H2 mass in th…
Modified Masses and Parallaxes of Close Binary Systems: HD 39438
Masda, Suhail; Yousef, Z. T.; Al-Wardat, Mashhoor +1 more
We present the detailed fundamental stellar parameters of the close visual binary system HD 39438 for the first time. We used Al-Wardat's method for analyzing binary and multiple stellar systems. The method implements Kurucz's plane parallel model atmospheres to construct synthetic spectral energy distributions (SEDs) for both components of the sy…
Photometric variations from stellar activity as an age indicator for solar-twins
Yana Galarza, Jhon; Lorenzo-Oliveira, Diego; Valio, Adriana +2 more
Stellar ages are elusive to measure, albeit being very important for understanding stellar evolution. We investigate the impact of photospheric activity on 2-min cadence light curves from the TESS/NASA mission of a selected sample of 30 solar-twins with well-determined ages. The photometric variability, $\mathcal {A}_{ {{TESS}}}$, of the light cur…
Numerical Prediction of Changes in Atmospheric Chemical Compositions During a Solar Energetic Particle Event on Mars
Leblanc, François; Vandaele, Ann Carine; Aoki, Shohei +11 more
Precipitation of solar energetic particles (SEPs) into planetary atmospheres causes changes in atmospheric chemical composition through ionization, dissociation, and excitation of atmospheric molecules. In contrast to the terrestrial atmosphere, where depletion of ozone in the polar mesosphere has been studied by observations and models for decade…
The magnetic fields around the cometary globules L328, L323, and L331
Soam, Archana; Roy, Nirupam; Kumar, Siddharth
This work presents the magnetic field geometry in a complex of three cometary (with head-tail morphology) globules, namely LDN 323, LDN 328, and LDN 331, using R-band polarization measurements of background stars. These observations were combined with a Planck sky survey to study the large-scale morphology of the magnetic fields in the region. The…
Solar coronal magnetic field measurements using spectral lines available in Hinode/EIS observations: strong and weak field techniques and temperature diagnostics
Chen, Yajie; Tian, Hui; Bai, Xianyong +4 more
Recently, it has been proposed that the magnetic-field-induced transition (MIT) in Fe X can be used to measure coronal magnetic field strengths. Several techniques, the direct line ratio technique and the weak and strong magnetic field techniques, are developed to apply the MIT theory to spectroscopic observations taken by EUV Imaging Spectrometer…
Radial velocity confirmation of a hot super-Neptune discovered by TESS with a warm Saturn-mass companion
McLeod, K. K.; Dai, F.; Gandolfi, D. +59 more
We report the discovery and confirmation of the planetary system TOI-1288. This late G dwarf harbours two planets: TOI-1288 b and TOI-1288 c. We combine TESS space-borne and ground-based transit photometry with HARPS-N and HIRES high-precision Doppler measurements, which we use to constrain the masses of both planets in the system and the radius o…
Correlation Study of Temporal and Emission Properties of Quiescent Magnetars
An, Hongjun; Seo, Jiwoo; Lee, Jaewon
We measured temporal and emission properties of quiescent magnetars using archival Chandra and XMM-Newton data, produced a list of the properties for 17 magnetars, and revisited previously suggested correlations between the properties. Our studies carried out with a larger sample, better spectral characterizations, and more thorough analyses not o…