Related papers: CC Bootis: QSO, Not Variable Halo Giant
We present the 13-year light curve of HW Boo between 2001 May and 2014 May. We identified 12 outbursts, which typically lasted 2 to 5 days, with an amplitude of 2.7 to 3.6 magnitudes. Time resolved photometry during two outbursts revealed…
In this Letter, we announce the discovery of a new satellite of the Milky Way in the constellation of Bootes at a distance of 60 kpc. It was found in a systematic search for stellar overdensities in the North Galactic Cap using Sloan…
We used the Near Infrared Camera on Keck I to obtain Ks-band images of four candidate high-redshift radio galaxies selected using optical and radio data in the NOAO Deep Wide-Field Survey in Bootes. Our targets have 1.4 GHz radio flux…
Three high-redshift (z=2) and high luminosity (M_B < -28 mag for Ho = 50, qo=0.5) QSOs, two radio-quiet one radio-loud, were imaged in R, I and K bands. The luminosities, colours and sizes of the hosts overlap with those of actively…
We report the discovery of a high redshift, narrow emission-line galaxy identified in the optical follow-up of deep ROSAT fields. The object has a redshift of z=2.35 and its narrow emission lines together with its high optical and X-ray…
Compact Symmetric Objects (CSOs) are young radio galaxies whose jet axes lie close to the plane of the sky, and whose appearance is therefore not dominated by relativistic beaming effects. The small linear sizes of CSOs make them valuable…
We present new V-band differential brightness measurements as well as new radial-velocity measurements of the detached, circular, 0.84-day period, double-lined eclipsing binary system CV Boo. These data along with other observations from…
We present optical candidates for 75 X-ray sources in a $\sim 1$ deg$^2$ overlapping region with the medium deep ROSAT survey. These candidates are selected using the multi-color CCD imaging observations made for the T329 field of the…
We examine high-cadence space photometry taken by the Transiting Exoplanet Survey Satellite (TESS) of a sample of evolved massive stars (26 Wolf-Rayet stars and 8 Luminous Blue Variables or candidate LBVs). To avoid confusion problems, only…
We report serendipitous optical imaging of CVSO30c, an exoplanet candidate associated with the pre-main sequence T Tauri star CVSO30 resides in the 25 Ori stellar cluster. We perform PSF modeling on our seeing limited optical image to…
We test the hypothesis whether high redshift QSOs would preferentially appear in small groups or pairs, and if they are associated with massive, young clusters. We carried out a photometric search for \Ly emitters on scales $\lesssim 10…
We have analysed around 170 000 individual photometric WASP measurements of 15 well established lambda Bootis stars to search for variability. The lambda Bootis stars are a small group of late-B to early-F, Pop. I, stars that show moderate…
A strong X-ray source only 8" from the nucleus of the Sy2 galaxy NGC 7319 in Stephan's Quintet has been discovered by Chandra. We have identified the optical counterpart and show it is a QSO with $z_e = 2.114$. It is also a ULX with $L_x =…
We report on the detection of a population of Red Clump (RC) stars probably associated with the recently discovered stellar system Bootes III. The RC is identified as a 3 sigma peak in the Luminosity Function (LF) of colour-selected stars…
Quasars (QSOs) are extremely luminous active galatic nuclei currently observed up to redshift $z=7.642$. As such, they have the potential to be the next rung of the cosmic distance ladder beyond SNe Ia, if they can reliably be used as…
(abridged) There is considerable interest in the possible interaction between parent stars and giant planetary companions in 51 Peg-type systems. We demonstrate from MOST satellite photometry and Ca II K line emission that there has been a…
An analysis is made of the spectral line shapes of tau Bootis using high resolution (0.026 A) and high signal-to-noise (S/N~400) data in an effort to confirm the planet hypothesis for this star. Changes in the line shape are quantified…
We present observations (with NAO Rozhen and AS Vidojevica telescopes) of the AM Canum Venaticorum (AM CVn) type binary star CR Bootis (CR Boo) in the UBV bands. The data were obtained in two nights in July 2019, when the V band brightness…
We report extensive multi-station photometry of TT Boo during its June 2004 superoutburst. The amplitude of the superoutburst was about 5.5 mag and its length over 22 days. The star showed a small re-brightening starting around the 9th day…
The brightest Fast Blue Optical Transients (FBOTs) are mysterious extragalactic explosions that may represent a new class of astrophysical phenomena. Their fast time to maximum brightness of less than a week and decline over several months…