Related papers: Fast optical variability of SS 433
We present our analysis of the extensive monitoring of SS433 by the RXTE observatory collected over the period 1996-2005. The difference between energy spectra taken at different precessional and orbital phases shows the presence of strong…
We present the first results from a detailed analysis of a new, long ($\sim100$ ks) XMM-Newton observation of the narrow-line Seyfert 1 galaxy PG 1404$+$226 which showed a large-amplitude, rapid X-ray variability by a factor of $\sim7$ in…
The Rapid Temporal Survey (RATS) explores the faint, variable sky. Our observations search a parameter space which, until now, has never been exploited from the ground. Our strategy involves observing the sky close to the Galactic plane…
T Tauri stars exhibit variability on all timescales, whose origin is still debated. On WTTS the variability is fairly simple and attributed to long-lived, ubiquitous cool spots. We investigate the long term variability of WTTS, extending up…
CONTEXT: The unparalleled characteristics of Gaia photometry make it an excellent choice to study stellar variability. AIMS: To measure the phot. dispersion in G+G_BP+G_RP of the 145 677 450 Gaia DR3 5-parameter sources with G <= 17 mag and…
The ultra-soft narrow-line Seyfert 1 galaxy 1H 0707-495 is a well-known and highly variable active galactic nucleus (AGN), with a complex, steep X-ray spectrum, and has been studied extensively with XMM-Newton. 1H 0707-495 was observed with…
Blazar S5 0716+714 is well-known for its short-term variability, down to intra-day time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in 2019 December - 2020 January and analyse the…
Despite decades of observations across all wavebands and dedicated theoretical modelling, the SS 433 system still poses many questions, especially in the high-energy range. SS 433 is a high-mass X-ray binary at a distance of $\sim 5.5$ kpc,…
We study the soft excess variability of the narrow line Seyfert 1 galaxy IRAS 13224-3809. We considered all five archival XMM-Newton observations, and we applied the 'flux-flux plot' (FFP) method. We found that the flux-flux plots were…
We present results of X-ray spectral and time-domain variability analyses of 4 faint, "quiescent" blazars from the Swift-BAT 105-month catalog. We use observations from a recent, 5-month long NICER campaign, as well as archival BAT data.…
Stars exhibit a bewildering variety of rapidly variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotation. The principal Rubin Observatory Legacy Survey of Space and…
The power spectrum of water optical turbulence is shown to vary with its average temperature $\left\langle T \right\rangle$ and average salinity concentration $\left\langle S \right\rangle$, as well as with light wavelength $\lambda$. This…
The detection of two sources of gamma rays towards the microquasar SS 433 has been recently reported. The first source can be associated with SS 433's eastern jet lobe, whereas the second source is variable and displays significant…
Using data from the (intermediate) Palomar Transient Factory (iPTF), we characterize the time variability of ~500 massive stars in M31. Our sample is those stars which are spectrally typed by Massey and collaborators, including Luminous…
The microquasar SS 433 is an interacting massive binary consisting of an evolved mass donor and a compact companion that ejects relativistic jets. The mass donor was previously identified through spectroscopic observations of absorption…
The Northern Sky Variability Survey (NSVS) is a temporal record of the sky over the optical magnitude range from 8 to 15.5. It was conducted in the course of the first generation Robotic Optical Transient Search Experiment (ROTSE-I) using a…
We report the detection of an extreme flux decrease accompanied by clear dispersion measure (DM) and rotation measure (RM) variations for pulsar B1929+10 during the 110-minute radio observation with the Five-hundred-meter Aperture Spherical…
We report the detection of a variable point source, imaged at L'(3.8 microns) with the W. M. Keck II 10-meter telescope's adaptive optics system, that is coincident to within 18 mas of the Galaxy's central supermassive black hole and the…
As part of our multiwavelength campaign of GX 339-4 observations in 1996 we present the rapid X-ray variability observed July 26 using the RXTE when the source was in a hard state (= soft X-ray low state). We found that the source was…
We present long term optical variability studies of bright X-ray sources in four nearby elliptical galaxies with {\it Chandra} Advanced CCD Imaging Spectrometer array (ACIS-S) and {\it Hubble Space Telescope (HST)} Advanced Camera for…