Search Publications
Analysis of a detached eclipsing binary at near the turnoff point of the open cluster NGC 6791 in Kepler field
Çakırlı, Ö.; Dervişoğlu, A.; Yontan, T. +2 more
We analyzed high-precision Kepler photometry and high-resolution UVES and GIRAFFE spectroscopy from ESO Science Archieve for a double-lined eclipsing binary star in the field of the high metallicity old open cluster NGC 6791. Earlier measurements of the masses and radii of the detached system were not accurate enough for photometric and spectrosco…
IGR J17503-2636: a candidate supergiant fast X-ray transient
Sanna, A.; Ferrigno, C.; Di Salvo, T. +4 more
The object IGR J17503-2636 is a hard X-ray transient discovered by INTEGRAL on 2018 August 11. This was the first ever reported X-ray emission from this source. Following the discovery, follow-up observations were carried out with Swift, Chandra, NICER, and NuSTAR. Here we report on the analysis of all of these X-ray data and the results obtained.…
The First Candidate Colliding-wind Binary in M33
Williams, Benjamin F.; Massey, Philip; Levesque, Emily M. +1 more
We present the detection of the first candidate colliding-wind binary (CWB) in M33, located in the giant H II region NGC 604. The source was first identified in archival Chandra imaging as a relatively soft X-ray point source, with the likely primary star determined from precise astrometric alignment between archival Hubble Space Telescope and Cha…
A real-time, high-accuracy, hardware-based integrated parameter estimator for deep space navigation and planetary radio science experiments
Liu, Wei; Wang, Zhen; Jian, Nianchuan +9 more
Real-time, high-accuracy frequency-phase estimation is the critical mission of Doppler tracking, which is a primary technique for deep space spacecraft navigation and planetary radio science experiments. Usually, the analog intermediate frequency signal is digitalized and converted to baseband by signal processing hardware platforms called digital…
How Much of the Sediment in Gale Crater's Central Mound Was Fluvially Transported?
Fassett, Caleb I.; Thomson, Bradley J.; Buczkowski, Debra L. +2 more
The origin of the sedimentary mound within Gale crater, the landing site for the Mars Science Laboratory rover Curiosity, remains enigmatic. Here we examine the total potential contribution of fluvial material by conducting a volume-based analysis. On the basis of these results, the mound can be divided into three zones: lower, intermediate, and u…
A nearby luminous AGN sample optically selected from Hubble Space Telescope
Li, Shuang-Liang
In this work, a nearby luminous active galactic nucleus (AGN) sample is selected from Hubble Space Telescope(HST), where only sources with both X-ray emission observed by Chandra/XMM-Newton and radio flux detected by Very Large Array (VLA)/Very Long Baseline Array (VLBA)/very long baseline interferometry (VLBI)/Multi-Element Radio Linked Interfero…
The Ursa Major Moving Group: a chronochemokinematic analysis
Sneden, C.; Dopcke, Gustavo; Porto de Mello, G. F.
Stars in kinematic groups are believed to share the same age, metallicity, and velocity vectors, and are disrupted by events such as encounters with massive objects, leaving a residue of stars sharing the same kinematic properties, thus bridging an important evolutionary gap between clusters and field stars. We determine the most likely metallicit…
Detection of a Low-mass Stellar Companion to the Accelerating A2IV Star HR 1645
Duchêne, Gaspard; Esposito, Thomas M.; Hom, Justin +51 more
The ∼500 Myr A2IV star HR 1645 has one of the most significant low-amplitude accelerations of nearby early-type stars measured from a comparison of the Hipparcos and Gaia astrometric catalogs. This signal is consistent with either a stellar companion with a moderate mass ratio (q ∼ 0.5) on a short period (P < 1 yr), or a substellar companion at…
Validation of MHD Model Predictions of the Corona with LASCO-C2 Polarized Brightness Images
Riley, Pete; Lamy, Philippe; Mikić, Zoran +1 more
Progress in our understanding of the solar corona requires that the results of advanced magnetohydrodynamic models driven by measured magnetic fields, and particularly the underlying heating models, be thoroughly compared with coronal observations. The comparison has so far mainly concerned the global morphology of the corona, synthetic images cal…
Multifilter time-series observations of three short period ATLAS variable stars
Koen, Chris
The `Asteroid Terrestrial-impact Last Alert System' discovered hundreds of thousands of new candidate variable stars. Follow-up observations of three of these are reported in this paper. The targets were selected on the basis of having high probability of being periodic (false alarm probability for period detection smaller than 10-5), s…