Related papers: A Search for SS Cyg Outburst Predictors

RU Peg is a dwarf nova (DN) of the U Gem type. Our analysis of its long-term optical activity uses the data from the AAVSO database. It concentrates on investigating the properties of the individual outbursts and the time evolution of the…

A strong outburst in the X-ray continuum and a change of its Seyfert spectral type was detected in HE 1136-2304 in 2014. The spectral type changed from nearly Seyfert 2 type (1.95) to Seyfert 1.5 type in comparison to previous observations…

We have observed YZ Cnc at two day intervals from 6 to 24 April 1998, covering two full outburst cycles. The 0.1-2.4 keV flux is lower during optical outburst than in quiescence, and lowest at the end of the outburst. The decline of the…

On 2015 June 15 the burst alert telescope (BAT) on board {\em Swift} detected an X-ray outburst from the black hole transient V404 Cyg. We monitored V404 Cyg for the last 10 years with the 2-m Faulkes Telescope North in three optical bands…

Swift J1822.3-1606 was discovered on 2011 July 14 by the Swift Burst Alert Telescope following the detection of several bursts. The source was found to have a period of 8.4377 s and was identified as a magnetar. Here we present a…

The magnetar Swift J1555.2-5402 was discovered in outburst on 2021 June 3 by the Burst Alert Telescope on board the Swift satellite. Early X-ray follow-up revealed a spin period P~3.86 s, a period derivative Pdot~3e-11 s/s, dozens of short…

We present new optical spectroscopy and photometry, 2MASS infrared observations and 24 years of combined AAVSO and AFOEV photometry of the symbiotic star candidate \ae. The long-term light curve is characterized by outbursts lasting several…

Nearby type Ia supernovae (SNe Ia), such as SN 2017cbv, are useful events to address the question of what the elusive progenitor systems of the explosions are. Hosseinzadeh et al. (2017) suggested that the early blue excess of the…

We study the spectral and temporal characteristics of the source GS 2023$+$338 (V404 Cyg) during the initial phase of its June 2015 outburst, over the energy range of 0.5 - 150 keV. This is the first detailed study of the characteristics of…

We describe the first results from a program of multi-wavelength monitoring of symbiotic binary stars in outburst. The prototypical symbiotic star Z Andromedae was observed extensively at radio, optical, far-UV, and X-ray wavelengths during…

GS 0836-429 is a neutron star X-ray transient that displays Type-I X-ray bursts. In 2003 and 2004 it experienced two outbursts in X-rays. We present here an analysis of the system bursting properties during these outbursts. We studied the…

We observed the 2015 July-August long outburst of V1006 Cyg and established this object to be an SU UMa-type dwarf nova in the period gap. Our observations have confirmed that V1006 Cyg is the second established object showing three types…

SwJ023017.0+283603 (SwJ0230) exhibited soft X-ray (0.3-1.0 keV) eruptions recurring roughly every 22 days. We present results from an extended monitoring campaign of SwJ0230 using Swift, NICER, and deep XMM-Newton observations. Our main…

We present a broadband X-ray study ($\sim$\,0.3-50 keV) of the dwarf nova SS Cyg highlighting the changes in the accretion during two phases, the quiescence and the outburst states. The investigation was based on simultaneous observations…

Aims. The blazars Mrk 421 and Mrk 501 have shown multiwavelength variability on all observed timescales, and have been well studied at high energies on short timescales. We aim to characterise the long-term temporal behaviour of these…

We report on NICER X-ray monitoring of the magnetar SGR 1830-0645 covering 223 days following its October 2020 outburst, as well as Chandra and radio observations. We present the most accurate spin ephemerides of the source so far:…

SU UMa stars are characterized by "superoutbursts" which are brighter at maximum light and which last much longer than the more frequent "ordinary" outbursts of these dwarf novae. Although there are now more than 1180 SU UMa type dwarf…

We measure the location and energetics of a SIV BALQSO outflow. This ouflow has a velocity of 10,800 km s$^{-1}$ and a kinetic luminosity of $10^{45.7}$ erg s$^{-1}$, which is 5.2% of the Eddington luminosity of the quasar. From collisional…

We use a sample of 3791 quasars from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), and compare their photometry to historic plate material for the same set of quasars in order to study their variability properties. The time…

In Kato et al. (2019, arXiv:1909.00910), I reported on a double outburst and rebrightenings in 2018 in V544 Her. Such a phenomenon is usually observed in WZ Sge stars which evolved after the period bounce and the colors of V544 Her in…