Search Publications
New H I observations of KK 69. Is KK 69 a dwarf galaxy in transition?
Koribalski, B. S.; Benaglia, P.; Saponara, J. +1 more
We present new H I data of the dwarf galaxy KK 69, obtained with the Giant Metrewave Radio Telescope (GMRT) with a signal-to-noise ratio almost double previous observations. We carried out a Gaussian spectral decomposition and stacking methods to identify the cold neutral medium (CNM) and the warm neutral medium (WNM) of the H I gas. We found that…
Soft proton scattering at grazing incidence from X-ray mirrors: analysis of experimental data in the framework of the non-elastic approximation
Santangelo, Andrea; Molendi, Silvano; Lotti, Simone +9 more
Astronomical X-ray observatories with grazing incidence optics face the problem of pseudo-focusing of low energy protons from the mirrors towards the focal plane. Those protons constitute a variable, unpredictable component of the non X-ray background that strongly affects astronomical observations and a correct estimation of their flux at the foc…
Improved photometric redshifts with colour-constrained galaxy templates for future wide-area surveys
Chary, Ranga-Ram; Lee, Bomee
Cosmology and galaxy evolution studies with LSST, Euclid, and Roman, will require accurate redshifts for the detected galaxies. In this study, we present improved photometric redshift estimates for galaxies using a template library that populates three-colour space and is constrained by HST/CANDELS photometry. For the training sample, we use a sam…
Chromospheric plasma ejection above a pore
Bharti, L.; Sobha, B.; Quintero Noda, C. +2 more
We present high spatial resolution observations of short-lived transients, ribbons and jet-like events above a pore in Ca II H images where fine structure, like umbral dots, light bridges and penumbral microfilaments, is present in the underlying photosphere. We found that current layers are formed at the edges of the convective fine structure, du…
TFAW survey - I. Wavelet-based denoising of K2 light curves. Discovery and validation of two new Earth-sized planets in K2 campaign 1
del Ser, D.; Fors, O.
The wavelet-based detrending and denoising method TFAW is applied for the first time to EVEREST 2.0-corrected light curves to further improve the photometric precision of almost all K2 observing campaigns (C1-C8, C12-C18). The performance of both methods is evaluated in terms of 6 h combined differential photometric precision (CDPP), simulated tra…
Updated pulsation period relations of γ Dor-type stars in eclipsing binaries: the case of KIC 2557430
Çakırlı, Ömür; Hoyman, Barış; Özdarcan, Orkun
We employ optical spectroscopy and Kepler photometry to derive the physical properties and pulsational characteristics of the detached system KIC 2557430. We find that the system is formed by F-type components. Combining results from the analysis of spectroscopic data and Kepler photometry, we calculate masses and radii of the primary and the seco…
Statistical Characteristics on SEPs, Radio-Loud CMEs, Low Frequency Type II and Type III Radio Bursts Associated with Impulsive and Gradual Flares
Prakash, O.; Shanmugaraju, A.; Kim, R. -S. +1 more
We have statistically analyzed a set of 115 low frequency (Deca-Hectometer wavelengths range) type II and type III bursts associated with major Solar Energetic Particle (SEP: Ep > 10 MeV) events and their solar causes such as solar flares and coronal mass ejections (CMEs) observed from 1997 to 2014. We classified them into two sets o…
Inferring Contributions from Unresolved Point Sources to Diffuse Emissions Measured in UV Sky Surveys: General Method and SOHO/SWAN Case Study
Bzowski, M.; Kubiak, M. A.; Kowalska-Leszczynska, I. +1 more
In observations of diffuse emissions like, e.g., the Lyα heliospheric glow, contributions to the observed signal from point sources (e.g., stars) are considered to be a contamination. There are relatively few bright point sources that are usually properly resolved and can be subtracted or masked. We present results of an analysis of the distributi…
Termination Shock as a Source of Unusual Solar Radio Bursts
Chernov, Gennady; Fomichev, Valery
Using centimeter-wave and decimeter-wave solar radio spectral observations of the flares of 2003 November 18 and 2004 September 12, we have discussed two type-II-like bursts at the meter waves. The radio bursts show that the ordinary frequency drift from high to low frequencies slows down and stops, and a frequency drift from low to high frequenci…
Infrared photometry of the dwarf nova V2051 Ophiuchi - II. The quiescent accretion disc and its spiral arms
Baptista, Raymundo; Wojcikiewicz, Eduardo
We report the analysis of time-series of infrared JHKs photometry of the dwarf nova V2051 Oph in quiescence with eclipse mapping techniques to investigate structures and the spectrum of its accretion disc. The light curves after removal of the ellipsoidal variations caused by the mass-donor star show a double-wave modulation signalling …