Related papers: SU Aur: A Deep Fading Event in Visible and Near-In…
AT 2018hyz (=ASASSN-18zj) is a tidal disruption event (TDE) located in the nucleus of a quiescent E+A galaxy at a redshift of $z = 0.04573$, first detected by the All-Sky Automated Survey for Supernovae (ASAS-SN). We present optical+UV…
We report on the first simultaneous near-infrared/X-ray detection of the Sgr A* counterpart which is associated with the massive black hole at the center of the Milky Way. The observations have been carried out using the NACO adaptive…
Sagittarius A*, the supermassive compact object at the center of the Galaxy, exhibits outbursts in the near infrared and X-ray domains. These flares are likely due to energetic events very close to the central object, on a scale of a few…
From the observations reported to VSNET, we detected short fading episodes in two dwarf novae, RX And (orbital period 5.0 hr) and SU UMa (orbital period 1.8 hr). The episodes in RX And can be naturally explained as the response to a…
Recent monitoring programs of ultra cool field M and L dwarfs (low mass stars or brown dwarfs) have uncovered low amplitude photometric I-band variations which may be associated with an inhomogeneous distribution of photospheric…
We report on the first simultaneous $NICER$ and $NuSTAR$ observations of the neutron star (NS) low-mass X-ray binary 4U 1735$-$44, obtained in 2018 August. The source was at a luminosity of $\sim1.8~(D/5.6\ \mathrm{kpc})^{2}\times10^{37}$…
Using recent data from photometric monitoring and data from the photographic plate archives we aim to study, the long-term photometric behavior of FUors. The construction of the historical light curves of FUors could be very important for…
We studied the IW And star V507 Cyg using ASAS-SN data, ZTF data and our snapshot photometry. The star has been found to be in a long standstill in 2020 May-2022 March (and it still continues now). Such long-lasting standstills have been…
A series of 353 red electronic spectra obtained between 1994 and 2010, and of 171 UBV photometric observations of the 2010 eclipse, were analyzed in an effort to better understand the eclipsing binary eps Aur. The main results follow. (1)…
Our current knowledge of star formation and accretion luminosity at high-redshift (z>3-4), as well as the possible connections between them, relies mostly on observations in the rest-frame ultraviolet (UV), which are strongly affected by…
We report the discovery with the Neutron Star Interior Composition Explorer (NICER) of narrow emission and absorption lines during photospheric radius expansion (PRE) X-ray bursts from the ultracompact binary 4U 1820-30. NICER observed the…
We monitored the recent FUor 2MASS J06593158-0405277 (V960 Mon) since November 2009 at various observatories and multiple wavelengths. After the outburst by nearly 2.9 mag in $r$ around September 2014 the brightness gently fades until April…
The past decade has experienced an explosive increase of optically-discovered tidal disruption events (TDEs) with the advent of modern time-domain surveys. However, we still lack a comprehensive observational view of their infrared (IR)…
Stars of late-M and L spectral types, collectively known as Ultracool Dwarfs (UCDs), may be excellent targets for searches for extrasolar planets. Owing to their small radii, the signal from an Earth-size planet transiting a UCD is, in…
Image saturation has been an issue for several instruments in solar astronomy, mainly at EUV wavelengths. However, with the launch of the Atmospheric Imaging Assembly (AIA) as part of the payload of the Solar Dynamic Observatory (SDO) image…
The Neutron Star Interior Composition Explorer (NICER) has observed seven thermonuclear X-ray bursts from the Low Mass X-ray Binary (LMXB) neutron star 4U 1728-34 from the start of the mission's operations until February of 2019. Three of…
We describe near-IR imaging data for a sample of 23 class I sources in the Taurus-Auriga dark clouds. Combining our data with previous photometry, we detect brightness variations of 0.1-0.5 mag in many sources. The near-IR morphologies are…
EE Cep is a unique system in which a Be star is eclipsed by a dark dusty disk, making this star similar to the famous epsilon Aur in many respects. The depth and the duration of the EE Cep eclipses change to a large extent. The last two…
We demonstrate the capability of AKARI for mapping diffuse far-infrared emission and achieved reliability of all-sky diffuse map. We have conducted an all-sky survey for more than 94 % of the whole sky during cold phase of AKARI observation…
The Solar Aspect Monitor (SAM) is a pinhole camera on the Extreme-ultraviolet Variability Experiment (EVE) aboard the Solar Dynamics Observatory (SDO). SAM projects the solar disk onto the CCD through a metallic filter designed to allow…