Search Publications
Stellar populations of the globular cluster NGC 5053 investigated using AstroSat-Ultra Violet Imaging Telescope
Nikitha, K. J.; Vig, S.; Ghosh, S. K.
Globular clusters (GCs), being old and densely packed, serve as ideal laboratories to test stellar evolution theories. Although there is enormous literature on GCs in optical bands, studies in the ultraviolet (UV) regime are sparse. In this work, we study the stellar populations of a metal-poor and a rather dispersed GC, NGC 5053, using the UV ins…
Water-maser survey towards off-plane O-rich AGBs around the orbital plane of the Sagittarius stellar stream
Zhang, Bo; Li, Jingjing; Wu, Yuanwei +1 more
A 22 GHz water-maser survey was conducted towards 178 O-rich asymptotic giant branch (AGB) stars with the aim of identifying maser emission associated with the Sagittarius stellar stream. In this survey, maser emissions were detected in 21 targets, 20 of which were new detections. We studied the Galactic distributions of H2O- and SiO-ma…
LAMOST J045019.27 + 394758.7, with peculiar abundances of N, Na, V, Zn, is possibly a Sculptor dwarf galaxy escapee
Shejeelammal, J.; Goswami, Aruna; Joshi, Santosh +5 more
We present the results of the high-resolution (R ~ 60 000) spectroscopic analysis of the star LAMOSTJ045019.27 + 394758.7 (hereafter J045) from the list of carbon stars of LAMOST DR2. From our analysis, we find that J045 does not exhibit the spectral characteristics of carbon stars. It is found to be a metal-poor ([Fe/H] = -1.05) giant that shows …
XMM-Newton observations of PSR J0554+3107: pulsing thermal emission from a cooling high-mass neutron star
Karpova, A. V.; Zyuzin, D. A.; Potekhin, A. Y. +2 more
XMM-Newton observations of the middle-aged radio-quiet γ-ray pulsar J0554+3107 allowed us, for the first time, firmly identify it in X-rays by detection of pulsations with the pulsar period. In the 0.2-2 keV band, the pulse profile shows two peaks separated by about a half of the rotation phase with the pulsed fraction of 25 ± 6 per cent. The prof…
A new insight of AGC 198691 (Leoncino) galaxy with MEGARA at the GTC
Castillo-Morales, A.; Gallego, J.; Mollá, M. +9 more
We describe the observations of the low metallicity nearby galaxy AGC 198691 (Leoncino Dwarf) obtained with the Integral Field Unit of the instrument MEGARA at the Gran Telescopio Canarias. The observations cover the wavelength ranges 4304-5198 Å and 6098-7306 Å with a resolving power R ≈ 6000. We present 2D maps of the ionized gas, deriving the e…
The hierarchical structure of galactic haloes: generalized N-dimensional clustering with C LUSTAR-ND
Lewis, Geraint F.; Oliver, William H.; Elahi, Pascal J.
We present C LUSTAR-ND, a fast hierarchical galaxy/(sub)halo finder that produces Clustering Structure via Transformative Aggregation and Rejection in N-Dimensions. It is designed to improve upon H ALO-OPTICS - an algorithm that automatically detects and extracts significant astrophysical clusters from the 3D spatial positions of simulation partic…
The first X-ray spectrum of the high-mass X-ray binary XTE J1855-026 during the compact object eclipse
Torrejón, J. M.; Sanjurjo-Ferrín, G.; Rodes-Roca, J. J.
We present the first XMM-Newton observation of the classical supergiant high-mass X-ray binary XTE J1855-026 taken entirely during the eclipse of the neutron star (NS), covering the orbital phases ϕ = 0.00-0.11. The analysis of the data allows us to (a) compare with the parameters obtained during the existing pre-eclipse observation and (b) explor…
Local Volume dwarf KK242: radial velocity, SF region, and metallicity
Burenkov, A. N.; Malygin, E. A.; Makarova, L. N. +5 more
KK242 is a LV dwarf of transition type residing in the void environment. Koda et al. present clear indications on its connection with Scd galaxy NGC 6503. This implies the distance to KK242 of ~6.3 Mpc and its MB = -10.5 mag. Its radial velocity, known from the Effelsberg radio telescope H I observations, reveals, however, the differenc…
High-contrast imaging of HD 29992 and HD 196385 with the Gemini Planet Imager
Petrucci, R.; Jofré, E.; Gómez, M. +1 more
Based on high-contrast images obtained with the Gemini Planet Imager (GPI), we report the discovery of two point-like sources at angular separations ρ ~ 0.18 and 0.80 arcsec from the stars HD 29992 and HD 196385. A combined analysis of the new GPI observations and images from the literature indicates that the source close to HD 29992 could be a co…
Chemical environments of 6.7 GHz methanol maser sources
Pandian, Jagadheep D.; Paulson, Sonu Tabitha
6.7 GHz methanol masers are the brightest of class II methanol masers that are regarded as excellent signposts in the formation of young massive stars. We present here a molecular line study of 68 6.7 GHz methanol maser hosts chosen from the Methanol Multibeam survey catalogue, which have MALT90 data available. We performed (1) pixel-by-pixel stud…