Search Publications
Post-flare formation of the accretion stream and a dip in pulse profiles of LMC X-4
Paul, Biswajit; Beri, Aru
We report here a pulse profile evolution study of an accreting X-ray pulsar LMC X-4 during and after the large X-ray flares using data from the two observatories XMM-Newton and RXTE. During the flares, the pulse profiles were found to have a significant phase offset in the range of 0.2-0.5 compared to the pulse profiles immediately before or after…
The Gaia Data Release 1 parallaxes and the distance scale of Galactic planetary nebulae
Stanghellini, Letizia; Bucciarelli, Beatrice; Lattanzi, Mario G. +1 more
In this paper we gauge the potentiality of Gaia in the distance scale calibration of planetary nebulae (PNe) by assessing the impact of DR1 parallaxes of central stars of Galactic PNe (CSPNe) against known physical relations. For selected PNe targets with state-of-the-art data on angular sizes and fluxes, we derive the distance-dependent parameter…
HD 240121 - An ACV variable showing anti-phase variations of the B and V light curves
Paunzen, Ernst; Gröbel, Rainer; Hümmerich, Stefan +1 more
The variability of HD 240121 = BD+59 2602 was first suspected by Särg and Wramdemark (1970) and later confirmed by Gröbel R. (1992a,b). Because of the observed anti-phase variations of the B and V light curves, the latter author tentatively suggested an ACV type. Apart from its inclusion in the catalog of New Suspected Variables (NSV 25977), no fu…
Orbital variations and outbursts of the unusual variable star V1129 Centauri
Bruch, Albert
The variable star V1129 Cen is classified in the GCVS as being of β Lyr type. Unusual for such stars, it exhibits outbursts roughly once a year, lasting for ∼ 40 days. For this reason, a relationship to the dwarf novae has been suspected. Here, for the first time a detailed analysis of the light curve of the system is presented. Based on observati…
Infrared photometric study of SDSS selected narrow line Seyfert 1 galaxies
Chen, P. S.; Liu, J. Y.; Shan, H. G.
The infrared photometric study of SDSS selected Narrow Line Seyfert 1 Galaxies (NLS1s) is presented in this paper. We have made cross-identifications for such NLS1s with 2MASS and WISE observations. Finally 992 NLS1s have 2MASS and WISE counterparts. Comparisons of NLS1s with the Broad Line Seyfert 1 (BLS1s) and Seyfert 2 galaxies are made. It is …
Ultraviolet spectroscopy of symbiotic nova V1016 Cyg with IUE and HST
Sanad, M. R.
We present International Ultraviolet Explorer (IUE) & Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) observations of the symbiotic nova V1016 Cyg through the period 1978 - 2000. Four spectra at different times revealing the changes in line fluxes are presented. The outflow velocity of the emitting region was calculated …
X-ray and optical orbital modulation of EXO 0748-676 : A co-variability study using XMM-Newton
Paul, Biswajit; Raman, Gayathri
We present a multi-wavelength timing study of the eclipsing low mass X-ray binary EXO 0748-676 (UY Vol) using XMM-Newton when the source was in a hard spectral state. The orbital optical and X-ray light curves show a fairly large amount of intensity modulation in the 7 observations taken during September-November, 2003, covering 36 complete binary…
Spectral and photometric behavior of SU UMa during quiescence and outburst states
Sanad, M. R.; Saad, S. M.; Zead, I. +2 more
We report the results of spectral and photometric observations of SU UMa. Available spectra from International Ultraviolet Explorer (IUE) and CCD photometry of five nights were used. Some profiles revealing the variations of some spectral lines at different times are presented. There is variation with time for photometric observations and the brig…
Spectral behavior of the symbiotic nova AG Pegasi observed with IUE and HST
Sanad, M. R.; Bobrowsky, M.
Ultraviolet spectra from the International Ultraviolet Explorer (IUE) and from the Hubble Space Telescope (HST) of the symbiotic novae AG Peg during the period 1978-1996 are analyzed. Some spectra showing the modulations of spectral lines at different times are presented. We determined the reddening from the 2200 Å feature, finding that E(B-V) = 0…
Compact star forming galaxies as the progenitors of compact quiescent galaxies: Clustering result
Fang, Guanwen; Kong, Xu; Fan, Lulu +1 more
We present a measurement of the spatial clustering of massive compact galaxies at 1.2 ≤ z ≤ 3 in CANDELS/3D-HST fields. We obtain the correlation length for compact quiescent galaxies (cQGs) at z ∼ 1.6 of r0 = 7.1-2.6+2.3 h-1 Mpc and compact star forming galaxies (cSFGs) at z ∼ 2.5 of r0 = 7.7…