Search Publications
Development and coupling test of active spacecraft potential control - Next generation (ASPOC-NG)
Cipriani, Fabrice; Nakamura, Rumi; Steller, Manfred +7 more
The active spacecraft potential control (ASPOC) system developed in the 1990s emits positive ions to neutralise the spacecraft potential, such as used in several missions like Geotail, Equator-S, Cluster, Doublestar and MMS. With the experience gained, the next generation of the active spacecraft potential control (ASPOC-NG) instrument has been de…
BCD spectrophotometry for massive stars in transition phases
Zorec, J.; Borges Fernandes, M.; Kraus, M. +7 more
Context. Stars in transition phases, such as those showing the B[e] phenomenon and luminous blue variables (LBVs), undergo strong, often irregular mass-ejection events. The prediction of these phases in stellar evolution models is therefore extremely difficult, if not impossible. As a result, their effective temperatures, their luminosities, and e…
Investigations of late-type giant stars from the First Byurakan Spectral Sky Survey
Gigoyan, K. K.; Gigoyan, K. S.; Kostandyan, G. R.
We study late-type giants found in the First Byurakan Survey (FBS) data base. The third Gaia data release (Gaia EDR3) photometric and astrometric data have been used to characterize our sample of 1 100 M-type giants and 130 C-type stars found at high latitudes. Phase dependent light-curves from large sky area variability data bases such as Catalin…
Galaksi Kümelerinde Küme İçi Gazın X-Işın Özelliklerinin İncelenmesi ile Kümelerin Dinamiksel Durumunu Belirleme ve Sınıflandırma
Yapucu, Zahide; Ikis Gün, Gülnur
Bu çalışmada, A0961, A2108, A3390 ve A3854 galaksi kümelerinin, XMM-Newton uydusu X-ışın gözlem verileri kullanılarak küme içi gazın X-ışın özellikleri incelenmiştir. Galaksi kümelerinin her biri için 0.4 - 7.2 keV enerji aralığında oluşturulan MOS1, MOS2 ve PN verileri birleştirilerek EPIC görüntüleri oluşturulmuştur. Galaksi kümelerinin dinamiks…
Extending time-series models for irregular observational gaps with a moving average structure for astronomical sequences
Elorrieta, F.; Eyheramendy, S.; Palma, W. +1 more
In this study, we introduce a novel moving-average model for analyzing stationary time-series observed irregularly in time. The process is strictly stationary and ergodic under normality and weakly stationary when normality is not assumed. Maximum likelihood (ML) estimation can be efficiently carried out through a Kalman algorithm obtained from th…
Infrared polarisation study of Lynds 1340: A case of RNO 8
Ganesh, Shashikiran; Rai, Archita
This paper describes the polarisation study of a Lynds cloud, LDN 1340,
Geometric Calibration of the ESA Mars Express Orbiter High Resolution Stereo Camera
Li, D.; Li, J.; Liu, W. +3 more
The high-resolution stereo camera mounted on the Mars Express (MEX) spacecraft of the European Space Agency is specifically designed for planetary photogrammetry and mapping missions. High-precision geometric calibration is required to maintain the geometric quality of satellite imaging. This study aimed to develop a Martian geometric calibration …
TFAW survey II: six newly validated planets and 13 planet candidates from K2
Tokovinin, A.; Dyachenko, V.; del Ser, D. +7 more
Searching for Earth-sized planets in data from Kepler's extended mission (K2) is a niche that still remains to be fully exploited. The TFAW survey is an ongoing project that aims to re-analyse all light curves in K2 C1-C8 and C12-C18 campaigns with a wavelet-based detrending and denoising method, and the period search algorithm TLS to search for n…
Solar source longitudinal dependence of SEPs and their association with solar flares and radio-loud CMEs
Moon, Y. -J.; Pappa Kalaivani, P.; Prakash, O. +4 more
In this article we examine the occurrence probability of 104 major (
Probing the nature of the X-ray source IGR J16327-4940 with Chandra
Sidoli, L.; Esposito, P.; Postnov, K. +3 more
We report on the results of a Chandra observation of the source IGR J16327-4940, suggested to be a high-mass X-ray binary hosting a luminous blue variable star (LBV). The source field was imaged by ACIS-I in 2023 to search for X-ray emission from the LBV star and eventually confirm this association. No X-ray emission is detected from the LBV star,…