Search Publications
Deriving physical parameters of unresolved star clusters. V. M 31 PHAT star clusters
Vansevičius, V.; Stonkutė, R.; de Meulenaer, P.
Context. This study is the fifth of a series that investigates the degeneracy and stochasticity problems present in the determination of physical parameters such as age, mass, extinction, and metallicity of partially resolved or unresolved star cluster populations in external galaxies when using HST broad-band photometry.
Aims: In this work w…
Catalogue of Coordinates and B-Magnitudes in -20° - +2° Zone Based on the Ulugh Beg Astronomical Institute Part of the Fon Project
Ehgamberdiev, Sh. A.; Andruk, V. M.; Muminov, M. M. +5 more
Catalogue of 13.4 million stars down to 17.5m was obtained in 2017 by using plates from the Kitab Observatory of Ulugh Beg Astronomical Institute (UBAI) of the Uzbek Academy of Sciences. Kitab's part of Photographic Sky Survey (Russian abbreviation is FON, in next contexts) project include more than 2600 photographic plates, exposed on …
Lessons Learned from the Three-view Determination of CME Mass
de Koning, Curt A.
With only single-viewpoint, total-brightness images, it is not possible to calculate the true mass of a coronal mass ejection (CME) because total-brightness images do not contain any depth information. If two viewpoints are available, it has been suggested that total-brightness images might be used to simultaneously derive the CME deprojected mass…
The role of strength defects in shaping impact crater planforms
Watters, W. A.; Geiger, L. M.; Fendrock, M. +2 more
High-resolution imagery and digital elevation models (DEMs) were used to measure the planimetric shapes of well-preserved impact craters. These measurements were used to characterize the size-dependent scaling of the departure from circular symmetry, which provides useful insights into the processes of crater growth and modification. For example, …
Synthetic IRIS spectra of the solar transition region: Effect of high-energy tails
Vocks, C.; Dzifčáková, E.; Dudík, J.
Aims: The solar transition region satisfies the conditions for presence of non-Maxwellian electron energy distributions with high-energy tails at energies corresponding to the ionization potentials of many ions emitting in the extreme-ultraviolet and ultraviolet portions of the spectrum.
Methods: We calculate the synthetic Si iv, O iv, a…
The tilting rate of the Milky Way's disc
Debattista, Victor P.; Macciò, Andrea V.; Earp, Samuel W. F. +1 more
We present tilting rates for galaxies comparable to the Milky Way (MW) in a Λ cold dark matter cosmological hydrodynamical simulation, and compare these with the predicted tilting rate detection limit of the Gaia satellite 0.28° Gyr-1. We first identify galaxies with mass comparable to the MW (9 × 1011 ≤ M200 ≤ 1.2…
Implications of MAVEN's planetographic coordinate system for comparisons to other recent Mars orbital missions
Withers, Paul; Jakosky, B. M.
The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission uses a planetographic coordinate system to report altitude, latitude, and longitude on Mars. By contrast, Mars Global Surveyor, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter generally used a planetocentric coordinate system. These two coordinate systems are different: latitud…
New Binaries in the ɛ Cha Association
Tokovinin, Andrei; Briceño, César
We present Adaptive Optics-aided speckle observations of 47 young stars in the ɛ Cha association made at the 4 m Southern Astrophysical Research Telescope in the I-band. We resolved 10 new binary pairs, 5 previously known binaries, and 2 triple systems, also previously known. In the separation range between 4 and 300 au, the 30 association members…
Far-infrared emission in luminous quasars accompanied by nuclear outflows
Hewett, P. C.; Dunne, L.; Dye, S. +9 more
Combining large-area optical quasar surveys with the new far-infrared (FIR) Herschel-ATLAS Data Release 1, we search for an observational signature associated with the minority of quasars possessing bright FIR luminosities. We find that FIR-bright quasars show broad C IV emission-line blueshifts in excess of that expected from the optical luminosi…
Coronal properties of the luminous radio-quiet quasar QSO B2202-209
Harrison, F. A.; Stern, D.; Behar, E. +8 more
We present an analysis of the joint XMM-Newton and NuSTAR observations of the radio-quiet quasar QSO B2202-209. Using an optical observation from the Hale Telescope at the Palomar Observatory, we revise the redshift of the source from the previously reported z = 1.77 to z = 0.532, and we estimate the mass of the central black hole, log (MBH