T. Kravtsov
A5050107096- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Magnetic confinement fusion research
- Astronomical Observations and Instrumentation
- Advanced Research in Systems and Signal Processing
- Pulsars and Gravitational Waves Research
- Solid State Laser Technologies
- Adaptive optics and wavefront sensing
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Laser Design and Applications
- Advanced Power Generation Technologies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Optical Wireless Communication Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Fluid Dynamics and Turbulent Flows
- Advanced Fiber Optic Sensors
University of Turku
2020-2025
European Southern Observatory
2023
Abstract We present the analysis of optical/near-infrared (NIR) data and host galaxy properties a bright, extremely-rapidly evolving transient, AT 2024wpp, which resembles enigmatic 2018cow. 2024wpp rose to peak brightness c = −21.9 mag in 4.3 d remained above half-maximum for only 6.7 d. The blackbody fits photometry show that event persistently hot (T ≳ 20 000 K) with rapidly receding photosphere (v ∼ 11 500 km s−1), similarly 2018cow albeit several times larger photosphere. JH reveal NIR...
We present photometric and spectroscopic data of the type IIb supernova (SN) 2024abfo in NGC 1493 (at 11 Mpc). The steroid Terrestrial-impact Last Alert System (ATLAS) survey discovered object just a few hours after explosion observed fast rise on first day. Signs sharp shock breakout peak subsequent cooling phase are ultraviolet bluest optical bands couple days, while no is visible reddest filters. Subsequently, analogy with normal SNe IIb, light curve SN rises again all to broad peak,...
We present optical and near-infrared photometry spectroscopy of SN 2023aew our findings on its remarkable properties. This event, initially resembling a Type IIb supernova (SN), rebrightens dramatically ∼90 d after the first peak, at which time spectrum transforms into that Ic. The slowly evolving specifically resembles post-peak Ic with relatively low line velocities even during second rise. reached 119 is both more luminous ( M r = −18.75 ± 0.04 mag) much broader than those typical SNe...
We present an extensive analysis of the optical and ultraviolet (UV) properties AT 2023clx, closest optical/UV tidal disruption event (TDE) to date ( z = 0.01107), which occurred in nucleus interacting low-ionization nuclear emission-line region (LINER) galaxy, NGC 3799. After correcting for host reddening E B − V ) h 0.179 mag), we find its peak absolute g -band magnitude be −18.03 ± 0.07 mag, bolometric luminosity L pk (1.57 0.19)×10 43 erg s −1 . 2023clx displays several distinctive...
ABSTRACT We present the analysis of SN 2020wnt, an unusual hydrogen-poor superluminous supernova (SLSN-I), at a redshift 0.032. The light curves 2020wnt are characterized by early bump lasting ∼5 d, followed bright main peak. reaches peak absolute magnitude M$_{r}^{\rm max}=-20.52\pm 0.03$ mag ∼77.5 d from explosion. This is lower end luminosity distribution SLSNe-I, but rise-time one longest reported to date. Unlike other spectra do not show O ii, strong lines C ii and Si detected....
We present an observational study of the luminous red nova (LRN) AT\,2021biy in nearby galaxy NGC\,4631. The field object was routinely imaged during pre-eruptive stage by synoptic surveys, but transient detected only at a few epochs from $\sim 231$\,days before maximum brightness. LRN outburst monitored with unprecedented cadence both photometrically and spectroscopically. shows short-duration blue peak, bolometric luminosity 1.6 \times 10^{41}$\,erg\,s$^{-1}$, followed longest plateau...
We present optical and near-infrared photometry spectroscopy of SN 2023aew our findings on its remarkable properties. This event, initially resembling a Type IIb supernova (SN), rebrightened dramatically $\sim$80 d after discovery, at which time spectrum transformed into that Ic. The slowly-evolving specifically resembled post-peak Ic with relatively low line velocities even during the second rise. peak, reached $\sim$107 is both more luminous ($M_r = -18.75\pm0.04$ mag) much broader than...
We present an extensive analysis of the optical and UV properties AT2023clx, closest TDE to date, that occurred in nucleus interacting LINER galaxy, NGC3799 (z=0.01107). After correcting for host reddening (E(B-V) = 0.179 mag), we find its peak absolute g-band magnitude be -18.03{+/-}0.07 mag, bolometric luminosity L=(1.57{+/-}0.19)x10^43 erg/s. AT2023clx displays several distinctive features: first, it rose within 10.4{+/-}2.5 days, making fastest rising date. Our SMBH mass estimate M_BH ~...
Spectral observations of the type-IIb supernova (SN) 2016gkg at 300-800 days are reported. The spectra show nebular characteristics, revealing emission from progenitor star's metal-rich core and providing clues to kinematics physical conditions explosion. dominated by lines [O I] $λ\lambda6300, 6364$ [Ca II] $λ\lambda7292, 7324$. Other notable, albeit weaker, include Mg $\lambda4571$, [Fe $\lambda7155$, O I $\lambda7774$, Ca II triplet, a broad, boxy feature location H$α$. Unlike in other...
The Multi-Unit Spectroscopic Explorer instrument (MUSE), is an integral-field spectrograph at one of the Nasmyth foci 8m-class Yepun telescope Paranal observatory. MUSE's most powerful modes use Adaptive Optics Facility consisting a Deformable Secondary Mirror with over 1000 actuators commanded by real-time computer up to times per second. At core system are 4 laser guide stars monitored GALACSI, wave-front sensor system. MUSE functions two modes: Wide-Field Mode (1'x1' field), making Ground...
We present an observational study of the luminous red nova (LRN) AT\,2021biy in nearby galaxy NGC\,4631. The field object was routinely imaged during pre-eruptive stage by synoptic surveys, but transient detected only at a few epochs from $\sim 231$\,days before maximum brightness. LRN outburst monitored with unprecedented cadence both photometrically and spectroscopically. shows short-duration blue peak, bolometric luminosity 1.6 \times 10^{41}$\,erg\,s$^{-1}$, followed longest plateau...
We present photometric and spectroscopic data on three extragalactic luminous red novae (LRNe): AT2018bwo, AT2021afy, AT2021blu. AT2018bwo was discovered in NGC45 (at 6.8 Mpc) a few weeks after the outburst onset. During monitoring period, transient reached peak luminosity of 10^40 erg/s. hosted by UGC10043 (49.2 Mpc), showed double-peaked light curve, with two peaks reaching similar 2.1(+-0.6)x10^41 For AT2021blu UGC5829, (8.6 pre-outburst phase well-monitored several surveys, object slow...
We report on our study of supernova (SN) 2022xxf based observations obtained during the first four months its evolution. The light curves (LCs) display two humps similar maximum brightness separated by 75 days, unprecedented for a broad-lined (BL) Type Ic (SN IcBL). SN is most nearby IcBL to date (in NGC 3705, $z = 0.0037$, at distance about 20 Mpc). Optical and near-infrared photometry spectroscopy are used identify energy source powering LC. Nearly 50 epochs high signal-to-noise-ratio were...
We present results from a five-month-long observing campaign of the unusual transient AT 2022fnm, which displays properties common to both luminous red novae (LRNe) and intermediate-luminosity transients (ILRTs). Although its photometric evolution is broadly consistent with that LRNe, no second peak apparent in light curve, spectral are more reminiscent ILRTs. It has fairly rapid rise time 5.3 ± 1.5 d, reaching absolute magnitude −12.7 0.1 (in ATLAS o band). find some evidence for...
We present results from a five-month-long observing campaign of the unusual transient AT 2022fnm, which displays properties common to both luminous red novae (LRNe) and intermediate-luminosity transients (ILRTs). Although its photometric evolution is broadly consistent with that LRNe, no second peak apparent in light curve, spectral are more reminiscent ILRTs. It has fairly rapid rise time 5.3$\pm$1.5 d, reaching absolute magnitude $-12.7\pm$0.1 (in ATLAS $o$ band). find some evidence for...
Context. Supernova remnants (SNRs) are the late stages of supernovae before their merging into surrounding medium. Oxygen-rich supernova represent a rare subtype with strong visible light oxygen emission. Aims. We present new method to detect SNRs exploiting capabilities modern visible-light integral-field units based on shapes SNR emission lines. Methods. search for unresolved shocked regions broadened lines using medium-resolution spectrograph MUSE Very Large Telescope. The spectral...
We present the analysis of optical data a bright and extremely-rapidly evolving transient, AT2024wpp, whose properties are similar to enigmatic AT2018cow (aka Cow). AT2024wpp rose peak brightness c=-21.9mag in 4.3d remained above half-maximum for only 6.7d. The blackbody fits multi-band photometry show that event persistently hot (T>20000K) with rapidly receding photosphere (v~11500km/s) until end photometric dataset at +16.1d post-discovery. This behaviour mimics AT2018cow, albeit several...
Abstract SN 2023tsz is a Type Ibn supernova (SNe Ibn), an uncommon subtype of stripped-envelope core-collapse SNe, discovered in extremely low-mass host. SNe are characterised by narrow helium emission lines their spectra and believed to originate from the collapse massive Wolf-Rayet (WR) stars, though progenitor systems still remain poorly understood. In terms energetics spectrophotometric evolution, largely typical example class, although line profile asymmetries nebular phase seen, which...
We present photometric and spectroscopic data on three extragalactic luminous red novae (LRNe): AT2018bwo, AT2021afy, AT2021blu. AT2018bwo was discovered in NGC45 (at 6.8 Mpc) a few weeks after the outburst onset. During monitoring period, transient reached peak luminosity of 10^40 erg/s. hosted by UGC10043 (49.2 Mpc), showed double-peaked light curve, with two peaks reaching similar 2.1(+-0.6)x10^41 For AT2021blu UGC5829, (8.6 pre-outburst phase well-monitored several surveys, object slow...
Abstract We investigate the thermal emission and extinction from dust associated with nearby superluminous supernova (SLSN) 2018bsz. Our dataset has daily cadence simultaneous optical near-infrared coverage up to ~ 100 days, together late time (+1.7 yr) MIR observations. At 230 days after light curve peak SN is not detected in optical, but shows a surprisingly strong excess, r - J > 3 mag K s 5 mag. The evolution of infrared enables us if mid-infrared newly formed inside ejecta,...
The Multi Unit Spectroscopic Explorer (MUSE) is an integral field spectrograph on the Very Large Telescope 4, capable of laser guide star assisted and tomographic adaptive optics using GALACSI module. Its observing capabilities include a wide (1 square arcmin), ground layer AO mode (WFM-AO) narrow (7.5"×7.5"), tomography (NFM-AO). latter has had several upgrades in 4 years since commissioning, including optimization control matrices for system new sub-electron noise detector its infra-red...