Related papers: A long term spectroscopic and photometric study of…
We present optical spectropolarimetry of the tidal disruption event (TDE) AT 2019qiz on days $+0$ and $+29$ relative to maximum brightness. Continuum polarization, which informs the shape of the electron-scattering surface, was found to be…
We present results from new optical and UV spectroscopy of the unusual binary system SS 433, and we discuss the relationship of the particular spectral components we observe to the properties of the binary. (1) The continuum spectrum which…
We present the UV photometry of the globular cluster NGC 1851 using images acquired with the Ultra-violet Imaging Telescope (UVIT) onboard the ASTROSAT satellite. PSF-fitting photometric data derived from images in two far-UV (FUV) filters…
A helium nova occurs on a white dwarf (WD) accreting hydrogen-deficient matter from a helium star companion. When the mass of a helium envelope on the WD reaches a critical value, unstable helium burning ignites to trigger a nova outburst.…
We analyze optical spectra of a two-ribbon, long duration C1.1 flare that occurred on 18 Aug 2011 within AR 11271 (SOL2011-08-18T15:15). The impulsive phase of the flare was observed with a comprehensive set of space-borne and ground-based…
Io's intense volcanic activity results in one of the most colorful surfaces in the solar system. Ultraviolet and visible-wavelength observations of Io are critical to uncovering the chemistry behind its volcanic hues. Here, we present…
The young open cluster NGC 6611 includes among its candidate members a class of peculiar objects with interesting properties: blue stars with infrared IR excesses. These stars show excesses in IR bands, signature of the presence of a…
We present single-epoch, post-maximum spectropolarimetry of four Type Ia supernovae (SNe Ia) that span a range of spectral and photometric properties: SN 2002bf and SN 2004dt exhibit unusually high-velocity (HV) absorption lines. SN 1997dt…
A large filament composed principally of two sections erupted sequentially in the southern hemisphere on January 26 2016. The central, thick part of the northern section was first lifted up and lead to the eruption of the full filament.…
We have performed our spectroscopic and multi-color photometric observations of the recurrent nova U Scorpii at the earliest stage of the 2010 outburst. 0.37 days after the discovery of the outburst, we can see broad and prominent emission…
The proto-planetary Red Rectangle nebula is powered by HD 44179, a spectroscopic binary (P = 318 d), in which a luminous post-AGB component is the primary source of both luminosity and current mass loss. Here, we present the results of a…
Through a program of narrow band imaging, we have observed the changing structure of the H alpha emission line around Nova Cyg 1992 (V1974 Cyg) at regular intervals from 1996 to 1999. Between 1994 and 1996, the nebular boundary advanced to…
Accreting planets have been detected through their hydrogen-line emission, specifically H$\alpha$. To interpret this, stellar-regime empirical correlations between the H$\alpha$ luminosity $L_\mathrm{H\alpha}$ and the accretion luminosity…
This work presents CHARA/VEGA H$\alpha$ spectro-interferometry (R ~ 6000, and $\lambda$/2B ~ 1 mas) of HD 179218 and HD 141569, doubling the sample of Herbig Ae/Be (HAeBe) stars for which this type of observations is available so far. The…
We report on the results of a new spectroscopic monitoring campaign of the quasar PG 0026+129 at the Calar Alto Observatory 2.2m telescope from July 2017 to February 2020. Significant variations in the fluxes of the continuum and…
The abundant population of "Little Red Dots" (LRDs)-compact objects with red UV to optical colors and broad Balmer lines at high redshift-is unveiling new insights into the properties of early active galactic nuclei (AGN). Perhaps the most…
We performed a detailed spectroscopic analysis of the dwarf nova V2051 Oph at the end of its 1999 superoutburst. We studied and interpreted the simultaneous behaviour of various emission lines. We obtained high-resolution echelle…
About 10% of all stars exhibit absorption lines of ultra-high excited (UHE) metals (e.g. OVIII) in their optical spectra when entering the white dwarf cooling sequence. The recent discovery of a both spectroscopic and photometric variable…
We present spatially resolved far-UV spectra (912-1840 A) of NGC 1068 obtained using the Hopkins Ultraviolet Telescope (HUT) during the March 1995 Astro-2 mission. Three spectra of this prototypical Seyfert 2 galaxy were obtained through a…
We analyze $\sim$32 years of optical spectra and photometry for the symbiotic binary PU Vul. Light curves for the He I $\lambda$4471, He II $\lambda$4686 and H$\beta$ $\lambda$4861 emission lines reveal an illumination effect, where the hot…