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Primary Black Hole Spin in OJ 287 as Determined by the General Relativity Centenary Flare
OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst
On the distance, reddening and progenitor of V838 Mon
Extensive optical and infrared photometry as well as low and high resolution spectroscopy are used as inputs in deriving robust estimates of the reddening, distance and nature of the progenitor of
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare: Improved Orbital Parameters
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations
MWC560—a unique astrophysical object
DESPITE its interesting behaviour1,2, the object MWC560 has been little studied since its discovery 50 years ago during the Mount Wilson Observatory Hα emission-line surveys3. To rectify this
Lithium in the symbiotic Mira V407 Cyg
We report an identification of the lithium resonance doublet Li i 6708  A in the spectrum of V407 Cyg, a symbiotic Mira with a pulsation period of about 745 d. The resolution of the spectra used was
Evaluating GAIA performances on eclipsing binaries. II. Orbits and stellar parameters for V781 Tau, UV Leo and GK Dra
The orbits and physical parameters of three close, double-lined G0 eclipsing binaries have been derived combining $H_{\rm P}, V_{\rm T}, B_{\rm T}$ photometry from the Hipparcos/Tycho mission with
The January 2015 outburst of a red nova in M 31
M31N 2015-01a (or M31LRN 2015) is a red nova that erupted in January 2015 -- the first event of this kind observed in M31 since 1988. Very few similar events have been confirmed as of 2015. Most of
A multiwavelength view on the dusty Wolf-Rayet star WR 48a ★
We present results from the first attempts to derive various physical characteristics of the dusty Wolf-Rayet star WR 48a based on a multi-wavelength view of its observational properties. This is
MWC 560: jets or optically thick expanding envelope?
Results of high- and low-resolution spectral and UBV photometric observations of MWC 560 during 1990 January-October are presented. Strong variations in the star brightness compared with previously