Search Publications
Very fast variations of SiO maser emission in evolved stars
Alcolea, J.; Bujarrabal, V.; de Vicente, P. +3 more
Context. Stars on the asymptotic giant branch (AGB) are long-period variables that present strong flux variations at almost all wavelengths, including the SiO maser lines. The periods of these variations are of 300-500 days in Mira-type stars and somewhat shorter in semi-regular variables. The variability of the SiO lines on short timescales has b…
Distribution of Water Vapor in Molecular Clouds. II
Bergin, Edwin A.; González-Alfonso, Eduardo; Tolls, Volker +8 more
The depth-dependent abundance of both gas-phase and solid-state water within dense, quiescent, molecular clouds is important to both the cloud chemistry and gas cooling. Where water is in the gas phase, it is free to participate in the network of ion-neutral reactions that lead to a host of oxygen-bearing molecules, and its many ortho- and para-en…
The ULX source X-3 in NGC 4258: a search for its X-ray and optical properties
Balman, S.; Akyuz, A.; Aksaker, N. +3 more
We present the results of a search for the nature of ultraluminous X-ray source (ULX) X-3 in the nearby galaxy NGC 4258. We use archival data from XMM-Newton, Chandra, NuSTAR, and Hubble Space Telescope (HST) observations. Total X-ray data were analysed to find that the model parameters of the system are indicative of a stellar-mass black hole, ∼1…
Gas-dust correlations in nearby galaxies: a case study of NGC 3184 and NGC 7793
Saikia, Gautam; Roy, Nirupam; Patra, Narendra Nath +1 more
The study of gas-dust interactions occurring in the interstellar medium of a galaxy is essential for understanding various physical processes taking place within it. A comparison of such events at different locations corresponding to diverse astrophysical environments provides more insight into the star formation as well as dust destruction condit…
Space, time and velocity association of successive coronal mass ejections
Gopalswamy, Nat; Yashiro, Seiji; Lara, Alejandro +2 more
Aims: Our aim is to investigate the possible physical association between consecutive coronal mass ejections (CMEs).
Methods: Through a statistical study of the main characteristics of 27 761 CMEs observed by SOHO/LASCO during the past 20 years.
Results: We found the waiting time (WT) or time elapsed between two consecutive CMEs is …
Hot Gas in Galaxy Halos Traced by Coronal Broad Lyα Absorbers
Richter, Philipp
We explore the possibility to systematically study the extended, hot gaseous halos of low-redshift galaxies with coronal broad Lyα absorbers (CBLAs). These are weak, thermally broadenend H I absorption lines arising from the tiny fraction of neutral hydrogen that resides in the collisionally ionized, million-degree halo gas in these galaxies. Usin…
BEER analysis of Kepler and CoRoT light curves - V. eBEER: extension of the algorithm to eccentric binaries
Mazeh, T.; Faigler, S.; Shahaf, S. +1 more
We present an extension of the BEER model for eccentric binaries - eBEER, approximating the BEaming, Ellipsoidal, and Reflection effects by harmonic series of the Keplerian elements of their orbit. As such, it can be a tool for fast processing of light curves for detecting non-eclipsing eccentric binary systems. To validate the applicability of th…
A Catalog of 531 White Dwarf Candidates in the Local Galactic Halo from Gaia Data Release 2
Kim, Bokyoung; Lépine, Sebastien; Medan, Ilija
We present a catalog of 531 white dwarf candidates that have large apparent transverse motions relative to the Sun ( ${v}_{T}\gt 200$ km s-1), thus making them likely members of the local Galactic halo population. The candidates were selected from the Gaia Data Release 2 and are located in a great circle with 20° width running across bo…
A Search for Transiting Planets in the Globular Cluster M4 with K2: Candidates and Occurrence Limits
Wallace, Joshua J.; Hartman, Joel D.; Bakos, Gáspár Á.
We perform a search for transiting planets in the NASA K2 observations of the globular cluster (GC) M4. This search is sensitive to larger orbital periods (P ≲ 35 days, compared to the previous best of P ≲ 16 days), and at the shortest periods, smaller planet radii (Rp ≳ 0.3 RJ, compared to the previous best of Rp …
Water vapour masers in long-period variable stars. II. The semi-regular variables R Crt and RT Vir
Engels, D.; Winnberg, A.; Brand, J.
Context. Water masers emitting at a radiofrequency of 22 GHz are often found in the circumstellar envelopes of evolved stars. We monitored the H2O maser emission of a larger sample of evolved stars of different types to study the maser properties as a function of stellar type.
Aims: We wish to understand the origin and evolution of…