Marie Karjalainen
A5057418227- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Particle Detector Development and Performance
- Astro and Planetary Science
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Gyrotron and Vacuum Electronics Research
- Nuclear Physics and Applications
- Calibration and Measurement Techniques
- Radiation Therapy and Dosimetry
- Particle physics theoretical and experimental studies
- Advanced X-ray and CT Imaging
- Cosmology and Gravitation Theories
- Advanced X-ray Imaging Techniques
- Isotope Analysis in Ecology
- Atmospheric Ozone and Climate
- Photocathodes and Microchannel Plates
Czech Academy of Sciences, Astronomical Institute
2021-2023
Universidad de La Laguna
2020-2022
Max Planck Institute for Physics
2021
Universidad Complutense de Madrid
2021
Instituto de Astrofísica de Canarias
2020-2021
Universitat de Barcelona
2021
The University of Tokyo
2021
University of Trieste
2021
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
2021
Institute for Fundamental Physics of the Universe
2021
On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of speed light in vacuo for as predicted by several quantum gravity models. Based on set assumptions possible intrinsic spectral and temporal evolution, we obtain competitive lower limits quadratic leading order modification.
With a day-side temperature in excess of 4500K, comparable to mid-K-type star, KELT-9b is the hottest planet known. Its extreme makes particularly interesting test bed for investigating nature and diversity gas giant planets. We observed transit at high spectral resolution (R$\sim$94,600) with CARMENES instrument on Calar Alto 3.5-m telescope. Using these data, we detect first time ionized calcium (CaII triplet) absorption atmosphere KELT-9b; this second that CaII has been hot Jupiter. Our...
The coincident detection of GW170817 in gravitational waves and electromagnetic radiation spanning the radio to MeV gamma-ray bands provided first direct evidence that short bursts (GRBs) can originate from binary neutron star (BNS) mergers. On other hand, properties GRBs high-energy gamma rays are still poorly constrained, with only $\sim$20 events detected GeV band, none TeV band. GRB~160821B is one nearest known at $z=0.162$. Recent analyses multiwavelength observational data its...
We report the detection of pulsed gamma-ray emission from Geminga pulsar (PSR J0633+1746) between $15\,$GeV and $75\,$GeV. This is first time a middle-aged has been detected up to these energies. Observations were carried out with MAGIC telescopes 2017 2019 using low-energy threshold Sum-Trigger-II system. After quality selection cuts, $\sim 80\,$hours observational data used for this analysis. To compare at lower energies below sensitivity range MAGIC, $11$ years Fermi-LAT above $100\,$MeV...
The goal of our study is to provide a reliable classification variability A-F stars brighter than 11 mag located in the northern TESS continuous viewing zone. We also aim at thorough discussion about issues related data characteristics and arising from similar light curve shape generated by different physical mechanisms. used long- short-cadence photometric corresponding Fourier transform classify type stars. present clear concise system that demonstrated on many examples. found signs 3025...
We present precise stellar radial velocity measurements of Gamma Dra taken from 2003 to 2017. The data 2011 show coherent, long-lived variations with a period 702 d. These are consistent the presence planetary companion having m sin i = 10.7 M_Jup whose orbital properties typical for giant planets found around evolved stars. An analysis Hipparcos photometry, Ca II S-index measurements, and spectral line shapes during this time no planet which seems "confirm"' planet. However, -- 2017 seem...
We present a detailed characterisation and theoretical interpretation of the broadband emission paradigmatic TeV blazar Mrk 421, with special focus on multi-band flux correlations. The dataset has been collected through an extensive multiwavelength campaign organised between 2016 December 2017 June. instruments involved are MAGIC, FACT, Fermi-LAT, Swift, GASP-WEBT, OVRO, Medicina Mets\"ahovi. Additionally, four deep exposures (several hours long) simultaneous MAGIC NuSTAR observations...
We report a characterization of the multi-band flux variability and correlations nearby (z=0.031) blazar Markarian 421 (Mrk 421) using data from Mets\"{a}hovi, Swift, Fermi-LAT, MAGIC, FACT other collaborations instruments November 2014 till June 2016. Mrk did not show any prominent flaring activity, but exhibited periods historically low activity above 1 TeV (F$_{>1\mathrm{TeV}}<$ 1.7$\times$10$^{-12}$ ph cm$^{-2}$ s$^{-1}$) in 2-10 keV (X-ray) band (F$_{2-10...
Context. QSO B1420+326 is a blazar classified as Flat Spectrum Radio Quasar (FSRQ). In the beginning of 2020 it underwent an enhanced flux state. An extensive multiwavelength campaign allowed us to trace evolution flare. Aims. We search for VHE gamma-ray emission from during this flaring aim characterize and model broadband source over different phases Methods. The was observed with number instruments in radio, near infrared, optical (including polarimetry spectroscopy), ultra-violet, X-ray...
The transmission spectrum of the ultrahot Jupiter KELT-9b ($T_{eq}$ $\sim$ 4000 K) exhibits absorption by several metal species. We searched for atomic and molecular lines in its emission observing partial phase curves with CARMENES spectrograph ($R$ 80,000 $-$ 95,000). find evidence Si I atmosphere first time. Additionally we Mg Ca II, which were previously detected transmission, confirmed earlier detections Fe emission. Conversely, no dayside from Al I, Cr FeH, K Li Na OH, Ti TiO, V VO, Y...
Abstract We report the discovery of two transiting planets around bright ( V = 9.9 mag) main-sequence F7 star TOI-1670 by Transiting Exoplanet Survey Satellite. b is a sub-Neptune <?CDATA ${R}_{{\rm{b}}}={2.06}_{-0.15}^{+0.19}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mi mathvariant="normal">b</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mn>2.06</mml:mn> <mml:mo>−</mml:mo>...
Gamma-ray bursts (GRBs) are the most energetic phenomena in Universe. Many aspects of GRB physics still under debate, such as origin their gamma-ray emission above GeV energy range. In 2019, MAGIC detected TeV gamma rays from long 190114C, whose can be well explained by synchrotron-self Compton relativistic electrons. However, it is unclear whether a process common GRBs, given reduced number GRBs until now at very high energies (VHE). 201216C and second one this After receiving alert...
We report the discovery of TOI-1268b, a transiting Saturn-mass planet from TESS space mission. With an age less than one Gyr, derived various indicators, TOI-1268b is youngest known to date and contributes small sample well characterised young planets. It has orbital period $P\,=\,8.1577080\pm0.0000044$ days, transits early K dwarf star with mass $M_\star$ = $ 0.96 \pm 0.04$ $M_{\odot}$, radius $R_\star$ 0.92 0.06$ $R_{\odot}$, effective temperature $T_\mathrm{eff}\,=\,5300\pm100$ K,...
We present the confirmation and characterization of three hot Jupiters, TOI-1181b, TOI-1516b, TOI-2046b, discovered by TESS space mission. The reported Jupiters have orbital periods between 1.4 2.05 days. masses planets are $1.18\pm0.14$ M$_{\mathrm{J}}$, $3.16\pm0.12$\, 2.30 $\pm 0.28$ for respectively. stellar host TOI-1181b is a F9IV star, whereas TOI-1516b TOI-2046b orbit F main sequence stars. ages first two systems in range 2-5 Gyrs. However, TOI-2046 among few youngest known planetary...
Aims . Over the past decades, libraries of stellar spectra have been used in a large variety science cases, including as sources reference for given object or spectral type. Despite existence and increasing number projects large-scale surveys, there is to date only one very high-resolution library offering from few hundred objects southern hemisphere (UVES-POP). We aim extend sample, finer coverage effective temperatures surface gravity with uniform collection obtained northern hemisphere....
Abstract We present the results of new time-series photometric observations 29 pre–white dwarf stars PG 1159 spectral type, carried out in years 2014–2022. For majority stars, a median noise level Fourier amplitude spectra 0.5–1.0 mmag was achieved. This allowed detection pulsations central star planetary nebula A72 (Abell 72), consistent with g modes excited GW Vir and variability RX J0122.9–7521 that could be due to pulsations, binarity, or rotation. remaining from sample were not observed...
Context. Diffusive shock acceleration (DSA) is the most promising mechanism to accelerate Galactic cosmic rays (CRs) in shocks of supernova remnants (SNRs). The turbulence upstream supposedly generated by CRs, but this process not well understood. dominant may depend on evolutionary state and can be studied via CRs escaping into interstellar medium (ISM). Aims. Previous observations $γ$-Cygni SNR showed a difference morphology between GeV TeV energies. Since has right age at stage for...
Disks in binary systems can cause exotic eclipsing events. MWC 882 (BD-22 4376, EPIC 225300403) is such a disk-eclipsing system identified from observations during Campaign 11 of the K2 mission. We propose that post-Algol with B7 donor star mass $0.542\pm0.053\,M_\odot$ 72 day period orbit around an A0 accreting $3.24\pm0.29\,M_\odot$. The $59.9\pm6.2\,R_\odot$ disk occults once every orbit, inducing 19 long, 7% deep eclipses by K2, and subsequently found pre-discovery ASAS ASAS-SN...
We report multiwavelength observations of the gravitationally lensed blazar QSO B0218+357 in 2016-2020. Optical, X-ray and GeV flares were detected. The contemporaneous MAGIC do not show significant very-high-energy (VHE, >= 100 GeV) gamma-ray emission. lack enhancement radio emission measured by OVRO indicates multi-zone nature from this object. constrain VHE duty cycle source to be < 16 2014-like per year (95% confidence). For first time for source, a broadband low-state SED is constructed...
The realtime follow-up of neutrino events is a promising approach to search for astrophysical sources. It has so far provided compelling evidence point source: the flaring gamma-ray blazar TXS 0506+056 was observed in coincidence with high-energy IceCube-170922A detected by IceCube. detection very-high-energy gamma rays (VHE, E > 100 GeV) from this source helped establish and constrained modeling emission at time IceCube event. four major imaging atmospheric Cherenkov telescope arrays...
Starting from the first announcement of unequivocal detection very high energy (VHE) emission a gamma-ray burst (GRB) by MAGIC telescopes (GRB 190114C), four additional detections VHE GRBs ground-based were reported. These observations have revealed new, energetic component that has become an probe to explore GRB physics. In order deepen our understanding origin this new component, and in general radiation GRBs, further instruments are crucial. work we report fast follow-up 201015A, detected...
Multiple long and variable transits caused by dust from possibly disintegrating asteroids were detected in light curves of WD 1145+017. We present time-resolved spectroscopic observations this target with QUCAM CCDs mounted the Intermediate dispersion Spectrograph Imaging System at 4.2-m William Herschel Telescope two different spectral arms: blue arm covering 3800-4025 {\AA} red 7000-7430 {\AA}. When comparing individual both arms, our show 20 {\sigma} significance an evident colour...
ABSTRACT We investigate the physical nature and origin of gamma-ray emission from extended source HESS J1841−055 observed at TeV GeV energies. energies for a total effective time 43 h with MAGIC telescopes, in 2012 2013. Additionally, we analysed counterpart making use about 10 yr Fermi-LAT data. Using both MAGIC, study spectral energy-dependent morphology almost four decades energy. The this region is investigated using multiwaveband information on sources present region, suggested to be...
We report here on the first multi-wavelength (MWL) campaign blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma rays (VHE). Up until now, this had not been subject of any detailed MWL observations. It has a rather hard photon index at GeV energies was considered candidate extreme high-synchrotronpeaked source. MAGIC observations resulted first-time detection source VHE with statistical significance 7.6$\sigma$. The average integral flux is 6 $\pm$ 1%...