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Atomic structure for carbon-like ions from Na VI to Ar XIII
Almodlej, A.; Alrashed, H.; Ben Nessib, N. +1 more
We have calculated the energy levels, oscillator strengths, and transition probabilities for eight carbon-like ions (Na VI, Mg VII, Al VIII, Si IX, P X, S XI, Cl XII and Ar XIII) using the Hartree-Fock pseudo-relativistic (HFR) and Thomas-Fermi-Dirac-Amaldi (TFDA) approaches. We used configuration expansions containing eight configurations, namely…
Study of UV-bright stellar populations in the globular cluster NGC 1261 using Astrosat
Rao, N. Kameswara; Sahu, Snehalata; Subramaniam, Annapurni +2 more
We present UV photometry of the globular cluster NGC 1261 using images acquired with the Ultraviolet Imaging Telescope (UVIT) on board Astrosat. We performed point-spread function (PSF) photometry on four near-UV (NUV) and two far-UV (FUV) images and constructed UV colour-magnitude diagrams (CMDs), in combination with the Hubble Space Telescope (H…
A new framework for understanding systematic errors in cluster lens modelling - II. Constraint selection
Keeton, Charles R.; Raney, Catie A.; Zimmerman, Dhruv T.
Cluster lens models are affected by a variety of choices in the lens modelling process. We have begun a programme to develop a systematic error budget for cluster lens modelling. Here, we examine the selection of image constraints as a potential systematic effect. For constraining the mass model, we find that it is more important to have images be…
An HST/STIS view of protoplanetary discs in Upper Scorpius: observations of three young M stars
Kalas, Paul; Carpenter, John; Ren, Bin +2 more
We present observations of three protoplanetary discs in visible scattered light around M-type stars in the Upper Scorpius OB association using the Space Telescope Imaging Spectrograph (STIS) instrument on the Hubble Space Telescope (HST). The discs around stars 2MASS J16090075-1908526, 2MASS J16142029-1906481, and 2MASS J16123916-1859284 have all…
Pairing function of visual binary stars
Chulkov, Dmitry
An all-sky sample of 1227 visual binaries based on Washington Double Star catalogue is constructed to infer the initial mass function (IMF), mass ratio, and projected distance distribution with a dedicated population synthesis model. Parallaxes from Gaia DR2 and Hipparcos are used to verify the distance distribution. The model is validated on the …
GG Carinae: discovery of orbital-phase-dependent 1.583-day periodicities in the B[e] supergiant binary
Podsiadlowski, Philipp; Porter, Augustus; Blundell, Katherine +1 more
GG Carinae (GG Car) is a binary whose primary component is a B[e] supergiant. Using photometric data from the Transiting Exoplanet Survey Satellite (TESS), All Sky Automated Survey (ASAS), Optical Monitoring Camera (OMC), and All Sky Automated Survey for Supernovae (ASAS-SN), and spectroscopic data from the Global Jet Watch to study visible He I, …
Spatial segregation impact on star formation in nearby dwarf spheroidal galaxies
Makarova, L. N.; Makarov, D. I.
Using our Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) observations of the recently found isolated dwarf spheroidal (dSph) galaxies, we homogeneously measured their star formation histories (SFHs). We determined SF rate as a function of time, as well as age and metallicity of the stellar populations. All objects demonstrate complex…
The Atacama Cosmology Telescope: SZ-based masses and dust emission from IR-selected cluster candidates in the SHELA survey
Papovich, Casey; Finkelstein, Steven L.; Hilton, Matt +19 more
We examine the stacked thermal Sunyaev-Zel'dovich (SZ) signals for a sample of galaxy group and cluster candidates from the 24 deg2 infrared Spitzer-HETDEX Exploratory Large Area (SHELA) survey. We identify the objects in combination with optical data using the redMaPPer algorithm, and divide them into three richness bins (λ in 10-20, 2…
Searching for Saturn's X-rays during a rare Jupiter Magnetotail crossing using Chandra
Jackman, C. M.; Branduardi-Raymont, G.; Nichols, J. D. +6 more
Every 19 yr, Saturn passes through Jupiter's 'flapping' magnetotail. Here, we report Chandra X-ray observations of Saturn planned to coincide with this rare planetary alignment and to analyse Saturn's magnetospheric response when transitioning to this unique parameter space. We analyse three Director's Discretionary Time (DDT) observations from th…
MEGARA-GTC stellar spectral library - II. MEGASTAR first release
Mollá, M.; Cardiel, N.; Gil de Paz, A. +4 more
MEGARA is an optical integral field and multi-object fibre-based spectrograph for the 10.4 m Gran Telescopio CANARIAS that offers medium-to-high spectral resolutions (FWHM) of R ≃ 6000, 12 000, 20 000. Commissioned at the telescope in 2017, it started operation as a common-user instrument in 2018. We are creating an instrument-oriented empirical s…