Search Publications
Circular Polarization Observations of Type II Solar Radio Bursts and the Coronal Magnetic Field
Ramesh, R.; Kathiravan, C.; Chellasamy, E. Ebenezer
It is well known that magnetic field strength (B) in the solar corona can be calculated using the Alfvén Mach number (M A ) and Alfvén speed (v A ) of the magnetohydrodynamic shock waves associated with coronal type II radio bursts. We show that observations of weak circularly polarized emission associated with the harmonic…
Distributed YSOs in the Perseus Molecular Cloud from the Gaia and LAMOST Surveys
Fang, Min; Herczeg, Gregory J.; Gao, Yu +5 more
Identifying the young optically visible population in a star-forming region is essential for fully understanding the star formation event. In this paper, we identify 211 candidate members of the Perseus molecular cloud based on Gaia astrometry. We use LAMOST spectra to confirm that 51 of these candidates are new members, bringing the total census …
Termination Shocks and the Extended X-Ray Emission in Mrk 78
Elvis, Martin; Gandhi, Poshak; Maksym, W. Peter +4 more
Subarcsecond imaging of the X-ray emission in the type 2 active galactic nucleus (AGN) Mrk 78 with Chandra shows complex structure with spectral variations on scales from ~200 pc to ~2 kpc. Overall the X-ray emission is aligned E-W with the radio (3.6 cm) and narrow emission line region as mapped in [O III], with a marked E-W asymmetry. The easter…
Blanco DECam Bulge Survey (BDBS). VII. Multiple Populations in Globular Clusters of the Galactic Bulge
Clarkson, William I.; Rich, R. Michael; Kunder, Andrea +9 more
We present photometric evidence for multiple stellar populations (MPs) in 14 globular clusters (GCs) toward the southern Galactic bulge. The photometric data come as part of the Blanco DECam Bulge Survey, which is a deep, wide-field near-UV-near-IR (ugrizY) survey of the southern Galactic bulge. Here, we present the first systematic study of bulge…
A Dearth of Close-in Planets around Rapidly Rotating Stars or a Dearth of Data?
De Medeiros, J. R.; Leão, I. C.; Canto Martins, B. L. +4 more
A dearth of close-in planets orbiting rapid rotators was reported almost a decade ago. According to this view, only slowly spinning stars with rotation periods longer than 5-10 days would host planets with orbital periods shorter than 2 or 3 days. This Letter brings an enlarged and more detailed analysis that led us to the question: Is there reall…
A Low-mass Pre-main-sequence Eclipsing Binary in Lower Centaurus Crux Discovered with TESS
Torres, Guillermo; Feliz, Dax L.; Stassun, Keivan G. +5 more
We report the discovery of 2M1222-57 as a low-mass, pre-main-sequence (PMS) eclipsing binary (EB) in the Lower Centaurus Crux (LCC) association for which, using Gaia parallaxes and proper motions with a neural net age estimator, we determine an age of 16.2 ± 2.2 Myr. The broadband spectral energy distribution (SED) shows clear excess at ≳10 µ…
How are Lyα Absorbers in the Cosmic Web Related to Gas-rich Galaxies?
Borthakur, Sanchayeeta
We present the correlation between Lyα absorbers and H I galaxies in the nearby universe (0.01 ≤ z ≤ 0.057). We find that Lyα absorbers are strongly correlated to H I galaxies at a projected separation of ≤0.5 Mpc and velocity separation of ≤50 km s-1. Lyα absorbers are 7.6 times more likely to be found near H I galaxies compared to a r…
WiNDS: An H α Kinematics Survey of Nearby Spiral Galaxies-Vertical Perturbations in Nearby Disk-type Galaxies
Monachesi, Antonela; Amram, Philippe; Gómez, Facundo A. +5 more
We present the Waves in Nearby Disk galaxies Survey (WiNDS) consisting of 40 nearby low-inclination disk galaxies observed through H α high-resolution Fabry-Perot interferometry. WiNDS consists of 12 new galaxy observations and 28 data archived observations obtained from different galaxy surveys. We derive two-dimensional line-of-sight…
Dust Emission as a Function of Stellar Population Age in the Nearby Galaxy M33
Calzetti, Daniela; Lin, Zesen; Mallory, Kate
Dust emission at 8 µm has been extensively calibrated as an indicator of current star formation rate for galaxies and ~kpc-size regions within galaxies. Yet, the exact link between the 8 µm emission and the young stellar populations in galaxies is still under question, as dust grains can be stochastically heated also by older field sta…
Testing the Cosmological Principle: Astrometric Limits on Systemic Motion of Quasars at Different Cosmological Epochs
Secrest, Nathan J.; Makarov, Valeri V.
A sample of 60,410 bona fide optical quasars with astrometric proper motions in Gaia Early Data Release 3 and spectroscopic redshifts above 0.5 in an oval 8400 square degree area of the sky is constructed. Using orthogonal Zernike functions of polar coordinates, the proper motion fields are fitted in a weighted least-squares adjustment of the enti…