Search Publications
Discovery of new mercury-manganese stars, including a fast rotator
Nuñez, N. E.; González, J. F.; Veramendi, M. E. +3 more
The origin of mercury-manganese (HgMn) stars is still poorly understood and the statistical analysis of an extensive sample of well characterized objects would be very valuable. Nevertheless, the compilation of a clean and reliable list of all known HgMn stars, and complete characterization of those objects, is still a pending issue. We report the…
Solar rotational period of cosmic rays and solar activity during the maximum phase of solar cycle 24
Singh, A. K.; Singh, P. R.; Farid, A. I. Saad +2 more
To study the solar rotational oscillation on daily averaged time series of solar activity proxies: sunspot number (SSN), modified coronal index (MCI), solar flare index (FI), and cosmic ray intensity (CRI) are subjected to Lomb/Scargle periodogram, and continuous wavelet transform. For this purpose, we have used data of all the considered paramete…
Searching for Active Low-mass Stars in the CMa Star-forming Region: Multi-band Photometry with T80S
Montmerle, T.; Galli, P. A. B.; Perottoni, H. D. +10 more
An exotic environment surrounds the young stellar groups associated with the Canis Major (CMa) OB1/R1 region, which probably was formed under feedback from at least three supernova events having occurred a few million years ago. We use astrometric data from the Gaia-DR2 to confirm the membership of the stars in CMa R1, based on proper motion and p…
Improvements to Pan-STARRS1 Astrometry Using Gaia
White, Richard L.; Shiao, Bernie; Lubow, Stephen H.
We use the Gaia DR2 catalog to improve the astrometric accuracy of about 1.7 billion objects in Pan-STARRS1 Data Release 2 (PS1 DR2). We also obtain proper motions for these PS1 objects. The cross-match between Gaia and PS1 reveals residuals that are correlated on a scale of about 1'. We apply a spatially adaptive correction algorithm for all PS1 …
Characterising atmospheric gravity waves on the nightside lower clouds of Venus: a systematic analysis
Lebonnois, S.; Machado, P.; Peralta, J. +3 more
We present the detection and characterisation of mesoscale waves on the lower clouds of Venus using images from the Visible Infrared Thermal Imaging Spectrometer onboard the European Venus Express space mission and from the 2 µm camera (IR2) instrument onboard the Japanese space mission Akatsuki. We used image navigation and processing techn…
Multi-epoch properties of the warm absorber in the Seyfert 1 galaxy NGC 985
Kaastra, J. S.; Kriss, G. A.; Ebrero, J. +1 more
Context. NGC 985 was observed by XMM-Newton twice in 2015, revealing that the source was coming out from a soft X-ray obscuration event that took place in 2013. These kinds of events are possibly recurrent since a previous XMM-Newton archival observation in 2003 also showed signatures of partial obscuration.
Aims: We have analyzed the high-re…
Discovery of 22 GHz Water Masers in the Serpens South Region
Gong, Yan; Pillai, Thushara; Loinard, Laurent +5 more
Using the Karl G. Jansky Very Large Array (VLA), we have conducted a survey for 22 GHz, 61,6-52,3 H2O masers toward the Serpens South region. The masers were also observed with the Very Long Baseline Array following the VLA detections. We detect for the first time H2O masers in the Serpens South region t…
AstroSat view of the NLS1 galaxy Mrk 335
Dewangan, Gulab C.; Misra, Ranjeev; Ezhikode, Savithri H.
We present the results from the multi-wavelength monitoring observations of the Narrow-Line Seyfert 1 galaxy Mrk 335 with AstroSat. We analysed both the X-ray (SXT and LAXPC) and UV (UVIT) data of the source at two epochs, separated by
Small-scale Bright Blobs Ejected from a Sunspot Light Bridge
Hou, Yijun; Chen, Yajie; Song, Yongliang +3 more
Light bridges (LBs) are bright lanes that divide an umbra into multiple parts in some sunspots. Persistent oscillatory bright fronts at a temperature of ∼105 K are commonly observed above LBs in the 1400/1330 Špassbands of the Interface Region Imaging Spectrograph (IRIS). Based on IRIS observations, we report small-scale bright blobs ej…
UV spectroscopy confirms SU Lyn to be a symbiotic star
Joshi, Vishal; Kumar, Vipin; Srivastava, Mudit K. +1 more
SU Lyn, a star that ostensibly appears to be an unremarkable late M type giant, has recently been proposed to be a symbiotic star largely based on its hard X-ray properties. The star does not display, in low-resolution optical spectra, the high excitation lines typically seen in the spectra of symbiotic stars. In this work, ultraviolet (UV), optic…