Related papers: AT 2019abn: multi-wavelength observations over the…

We present a study of SN 2009js in NGC 918. Multi-band Kanata optical photometry covering the first ~120 days show the source to be a Type IIP SN. Reddening is dominated by that due to our Galaxy. One-year-post-explosion photometry with the…

We present the discovery of a luminous X-ray transient, serendipitously detected by Swift's X-ray Telescope (XRT) on 2020 February 5, located in the nucleus of the galaxy SDSS J143359.16+400636.0 at z=0.099 (luminosity distance $D_{\rm…

In this Letter, we report the discovery of an ultraluminous fast-evolving transient in rest-frame UV wavelengths, MUSSES2020J, soon after its occurrence by using the Hyper Suprime-Cam (HSC) mounted on the 8.2 m Subaru telescope. The rise…

We present early-time ($t < +50$ days) observations of SN 2019muj (= ASASSN-19tr), one of the best-observed members of the peculiar SN Iax class. Ultraviolet and optical photometric and optical and near-infrared spectroscopic follow-up…

Here, we present MAXI, SWIFT, NICER, NuSTAR and Chandra observations of the X-ray transient AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234). From spectral and timing analyses we classify it as a Galactic low-mass X-ray binary…

We present the discovery of ASASSN-18jd (AT 2018bcb), a luminous optical/UV/X-ray transient located in the nucleus of the galaxy 2MASX J22434289--1659083 at $z=0.1192$. Over the year after discovery, Swift UVOT photometry shows the UV SED…

The fast-rising blue optical transient AT2018cow indicated unusual early phase characteristics unlike relatively better studied explosive transients. Its afterglow may be produced by either a relativistically beamed (jetted) or…

We present an analysis of the optical and UV properties of AT 2020wey, a faint and fast tidal disruption event (TDE) at 124.3 Mpc. The light curve of the object peaked at an absolute magnitude of $M_{g} = -17.45$ mag and a maximum…

We present the discovery of the Optical Transient (OT) of the long-duration gamma-ray burst GRB000926. The optical transient was detected independently with the Nordic Optical Telescope and at Calar Alto 22.2 hours after the burst. At this…

We present detailed, multi-wavelength analysis of GRB 210704A: a Fermi Gamma-ray Burst Monitor discovered and Fermi Large Area Telescope (LAT) detected gamma-ray burst (GRB). The burst is dominated by a short ($\approx 2$ s) pulse followed…

We explore the stellar population of M31 in a Spitzer Space Telescope survey utilizing IRAC and MIPS observations. Red supergiants are the brightest objects seen in the infrared; they are a prominent evolutionary phase. Due to their…

The physical origin of fast radio bursts (FRBs) remains unclear. Finding multiwavelength counterparts of FRBs can be a breakthrough in understanding their nature. In this work, we perform a systematic search for astronomical transients…

With a growing number of facilities able to monitor the entire sky and produce light curves with a cadence of days, in recent years there has been an increased rate of detection of sources whose variability deviates from standard behavior,…

The optical counterpart of the Gamma-Ray Burst GRB 970228, discovered by Groot et al. (IAU Circ. 6584), is also detected in the B and R frames obtained about 4 hours earlier at the Bologna Observatory. Our observations indicate a very…

We present a search for extragalactic fast blue optical transients (FBOTs) during Phase I of the Zwicky Transient Facility (ZTF). We identify 38 candidates with durations above half-maximum light 1 d < t1/2 < 12 d, of which 28 have blue…

A very unique strength of the Devasthal Observatory is its capability of detecting optical transients with the 4-m International Liquid Mirror Telescope (ILMT) and to rapidly follow them up using the 1.3-m Devasthal Fast Optical Telescope…

We present the discovery of AT 2024wpp ("Whippet"), a fast and luminous 18cow-like transient. At a redshift of z=0.0868, revealed by Keck Cosmic Web Imager spectroscopy of its faint star-forming host, it is the fourth-nearest example of its…

Radio wavelengths offer a unique window into high-energy astrophysical phenomena that may be obscured or too rapidly evolving to be captured at other wavelengths. Leveraging data from the Very Large Array Sky Survey, we perform a systematic…

We present the results of the analysis of the SRG/ART-XC observation of the Supergiant Fast X-ray Transient IGR J16195-4545 performed on March 3, 2021. Six bright flares are present in the light curve, with no significant change in hardness…

We present a Spitzer/IRS low-resolution mid-infrared spectrum (5-14 micron) of the luminous transient discovered in the nearby galaxy NGC 300 in May 2008. The spectrum, obtained three months after discovery, shows that the transient is very…