Search Publications
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…
XMM-Newton and NuSTAR Observations of the Compact Millisecond Pulsar Binary PSR J1653-0158
Wu, Kinwah; Kong, Albert K. H.; Takata, Jumpei +4 more
We have presented the first joint XMM-Newton and NuSTAR analysis of the millisecond pulsar (MSP) binary PSR J1653-0158. The 75 minute orbital period inferred from optical and gamma-ray observations together with the 1.97 ms pulsation in the gamma-rays indicate that this system is the most compact Black Widow MSP system known to date. The orbital p…
Solar Polar Flux Redistribution Based on Observed Coronal Holes
Jones, Shaela I.; Arge, Charles N.; Henney, Carl J. +1 more
We explore the use of observed polar coronal holes (CHs) to constrain the flux distribution within the polar regions of global solar magnetic field maps in the absence of reliable quality polar field observations. Global magnetic maps, generated by the Air Force Data Assimilative Photospheric flux Transport (ADAPT) model, are modified to enforce f…
Estimating the Spin of the Black Hole Candidate MAXI J1659-152 with the X-Ray Continuum-fitting Method
Steiner, James F.; Gou, Lijun; Wu, Jianfeng +6 more
As a transient X-ray binary, MAXI J1659-152 contains a black hole candidate as its compact star. MAXI J1659-152 was discovered on 2010 September 25 during its only known outburst. Previously published studies of this outburst indicate that MAXI J1659-152 may have an extreme retrograde spin, which, if confirmed, would provide an important clue as t…
Searching for Cataclysmic Variable Stars in Unidentified X-Ray Sources
Takata, J.; Kong, A. K. H.; Hui, C. Y. +6 more
We carry out a photometric search for new cataclysmic variable stars (CVs), with the goal of identification for candidates of AR Scorpii-type binary systems. We select GAIA sources that are likely associated with unidentified X-ray sources, and analyze the light curves taken by the Zwicky Transient Facility, Transiting Exoplanet Survey Satellite, …
X-Ray and GeV-γ-Ray Emission Property of TeV Compact Symmetric Object PKS 1413+135 and Implication for Episodic Jet Activity
Liang, En-Wei; Yao, Su; Zhang, Hai-Ming +3 more
PKS 1413+135, a compact symmetric object (CSO) with a two-sided parsec-scale structure in its miniature radio morphology, is spatially associated with 4FGL J1416.1+1320 and recently detected with MAGIC telescopes. We comprehensively analyze its X-ray and gigaelectronvolt γ-ray observation data to reveal its high-energy radiation physics. It is fou…
A Magnetic Valve at L1 Revealed in TESS Photometry of the Asynchronous Polar BY Cam
Ramsay, Gavin; Garnavich, Peter; Littlefield, Colin +7 more
We present TESS photometry of the asynchronous polar BY Cam, which undergoes a beat cycle between the 199.384 min white dwarf (WD) spin period and the 201.244 min orbital period. This results in changes in the flow of matter onto the WD. The TESS light curve covers 92% of the beat cycle once and 71% of the beat cycle twice. The strongest photometr…