Related papers: Stellar Variability in a Forming Massive Star Clus…

The VISTA Variables in the Via Lactea (VVV) survey obtained near-infrared photometry toward the Galactic bulge and the southern disc plane for a decade (2010 - 2019). We designed a modified Lomb-Scargle method to search for large-amplitude…

Swift J1858.6-0814 is a recently discovered X-ray binary notable for extremely strong variability (by factors $>100$ in soft X-rays) in its discovery state. We present the detection of five thermonuclear (Type I) X-ray bursts from Swift…

Time-series data taken with the Hubble Space Telescope of a field six core radii (~5') from the center of the globular cluster Messier 4, and covering a period of about 10 weeks in early 2001, have been analyzed in search of variable…

We present new deep UBVRI images and high-resolution multi-object optical spectroscopy of the young (~ 6 - 10 Myr old), relatively nearby (800 pc) open cluster IC 2395. We identify nearly 300 cluster members and use the photometry to…

Using the public data from the Herschel wide field surveys, we study the far-infrared properties of optical-selected quasars from the Sloan Digital Sky Survey. Within the common area of $\sim 172~deg^2$, we have identified the far-infrared…

Massive stars have an impact on their surroundings from early in their formation until the end of their lives. However, very little is known about their formation. Episodic accretion may play a crucial role, but observations of these events…

NGC 6441 is a bulge globular cluster with an unusual horizontal branch morphology and a rich population of RR Lyrae (RRL) and Type II Cepheid (T2C) variables that is unexpected for its relatively high metallicity. We present near-infrared…

We searched the light curves of over 40000 stars in the 2MASS calibration database, spanning approximately 4 years, for objects that have significant day long dimming events. We also searched the multi-color light curves for red dimming…

Young stars exhibit short-term photometric variability caused by mass accretion events from circumstellar disks, the presence of dusty warps within the inner disks, starspots that rotate across the stellar surfaces, and flares. Long-term…

We combine VLT/ISAAC NIR spectroscopy with archival HST/WFPC2 and HST/NICMOS imaging to study the central 20"x20" of M83. Our NIR indices for clusters in the circumnuclear star-burst region are inconsistent with simple instantaneous burst…

We present a catalog of 110 variable stars within ~1' of Sgr A* based on image subtraction of near-infrared (H and K) photometry. Our images were obtained over 133 nights from 2000--2002 in H-band and over 134 nights from 2001--2002 in…

We present HST/NICMOS observations with 0.1" (15 AU) resolution of six young stellar objects in the Taurus star-formation region. The targets of our survey are three Class I IRAS sources (IRAS 04016+2610, IRAS 04248+2612, and IRAS…

We used four-year baseline HST/WFC3 IR observations of the Galactic Centre in the F153M band (1.53 micron) to identify variable stars in the central ~2.3'x2.3' field. We classified 3845 long-term (periods from months to years) and 76…

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). The main aim was to identify stars in the very final stage of their evolution, and for which the…

To search for optical variability on a wide range of timescales, we have carried out photometric monitoring of 3C 454.3, 3C 279 and S5 0716+714. CCD magnitudes in B, V, R and I pass-bands were determined for $\sim$ 7000 new optical…

Using newly released data from the Wide-field Infrared Survey Explorer, we report the discovery of rapid infrared variability in three radio-loud narrow-line Seyfert 1 galaxies (NLS1s) selected from the 23 sources in the sample of Yuan et…

FU Ori outbursts are thought to play a key role in stellar mass assembly and in the chemistry of protoplanetary disks during the early formation of stars. However, uncertainties remain regarding the universality of these events and the…

The IceCube instrument detected a high-energy cosmic neutrino event on 2017 September 22 (IceCube_170922A, IceCube Collaboration 2018), which the electromagnetic follow-up campaigns associated with the flaring $\gamma$-ray blazar TXS…

We report on two photometric monitoring campaigns of Very Low Mass (VLM) objects in the young open cluster around SigmaOrionis. Our targets were pre-selected with multi-filter photometry in a field of 0.36 sqdeg. For 23 of these objects,…

Optical variability in galaxies at high redshift is a tracer of evolution in AGN activity, and should provide a useful constraint on models of galaxy evolution, AGN structure, and cosmology. We studied optical variability in multiple deep…