33 citations · 119 across the 18 of their papers we have counts for
18 papers
Project Hephaistos -- III. Characterizing anomalous infrared sources identified as Dyson-sphere candidates
Andreas J. Korn, Matías Suazo, Erik Zackrisson +3
The infrared-flux excess of stars harbouring Dyson spheres represent one potential technosignature of extraterrestrial intelligence. In a previous Project Hephaistos paper, we high…
Project Hephaistos -- IV. James Webb Space Telescope Observations of Two Dyson Sphere Candidates
Erik Zackrisson, Arjan Bik, Anita Ali Asgar +11
We report on JWST/MIRI imaging and spectroscopy of two M-dwarf stars previously singled out by project Hephaistos as potential Dyson-sphere candidates (their candidates D and E) du…
Mirror images of lensed star clusters with mismatched spectral energy distributions: A possible signature of top-heavy stellar initial mass functions and extreme stars in high-redshift star clusters
Erik Zackrisson, Jose M. Diego, Jose M. Palencia +4
Strongly lensed star clusters have recently been detected up to redshift in galaxy cluster fields using the James Webb Space Telescope (JWST). When pairs of mirror im…
Explanations for the two-component spectral energy distributions of gravitationally lensed stars at high redshifts
Armin Nabizadeh, Erik Zackrisson, Emma Lundqvist +4
Observations of gravitationally lensed, high-mass stars at redshifts occasionally reveal spectral energy distributions that contain two components with different effecti…
Identification of 40 gravitationally magnified stars in a galaxy at redshift of 0.725
Yoshinobu Fudamoto, Fengwu Sun, Jose M. Diego +44
Strong gravitational magnifications enable to detect faint background sources, resolve their internal structures, and even identify individual stars in distant galaxies. Highly mag…
The detection and characterization of highly magnified stars with JWST: Prospects of finding Population III
Erik Zackrisson, Adam Hultquist, Aron Kordt +10
Gravitational lensing may render individual high-mass stars detectable out to cosmological distances, and several extremely magnified stars have in recent years been detected out t…
A search for high-redshift direct-collapse black hole candidates in the PEARLS north ecliptic pole field
Armin Nabizadeh, Erik Zackrisson, Fabio Pacucci +31
Direct-collapse black holes (DCBHs) of mass - that form in HI-cooling halos in the early Universe are promising progenitors of the $\gtrsim 10^9 {M}_\odo…
Broad-band analysis of X-ray pulsar 2S 1845024
Armin Nabizadeh, Sergey S. Tsygankov, Sergey V. Molkov +4
We present results of detailed investigation of the poorly studied X-ray pulsar 2S 1845024 based on the data obtained with observatory during the type I outburst in 201…
First detection of VHE gamma-ray emission from TXS~1515--273, study of its X-ray variability and spectral energy distribution
MAGIC Collaboration, V. A. Acciari, S. Ansoldi +196
We report here on the first multi-wavelength (MWL) campaign on the blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma rays (VHE). Up until n…
X-ray reprocessing in accreting pulsar GX 301-2 observed with Insight-HXMT
L. Ji, V. Doroshenko, V. Suleimanov +100
We investigate the absorption and emission features in observations of GX 301-2 detected with Insight-HXMT/LE in 2017-2019. At different orbital phases, we found prominent Fe Kalph…
Testing two-component models on very-high-energy gamma-ray emitting BL Lac objects
MAGIC Collaboration, V. A. Acciari, S. Ansoldi +201
Context. It has become evident that one-zone synchrotron self-Compton models are not always adequate for very-high-energy (VHE) gamma-ray emitting blazars. While two-component mode…
Spectral evolution of X-ray pulsar 4U 1901+03 during the 2019 outburst based on Insight-HXMT and NuSTAR observations
Armin Nabizadeh, Sergey S. Tsygankov, Long Ji +7
We report on a detailed spectral analysis of emission from X-ray pulsar 4U 1901+03 using data obtained by the Insight-HXMT and NuSTAR observatories during the 2019 outburst of the…
Insight-HXMT insight into switch of the accretion mode: the case of the X-ray pulsar 4U 1901+03
Y. L. Tuo, L. Ji, S. S. Tsygankov +116
We use the In data collected during the 2019 outburst from X-ray pulsar 4U 1901+03 to complement the orbital parameters reported by Fermi/GBM. Using the Insight-HXMT, we examine th…
Discovery of a retrogradely rotating neutron star in the X-ray pulsar GX 3012
Juhani Mönkkönen, Victor Doroshenko, Sergey S. Tsygankov +3
We report on the analysis of the spin evolution of a slow X-ray pulsar GX 3012 along the orbit using long-term monitoring by Fermi/GBM. Based on the observationally confirmed ac…
Switches between accretion structures during flares in 4U 1901+03
L. Ji, L. Ducci, A. Santangelo +120
We report on our analysis of the 2019 outburst of the X-ray accreting pulsar 4U 1901+03 observed with Insight-HXMT and NICER. Both spectra and pulse profiles evolve significantly i…
X-ray properties of dwarf nova EY Cyg and the companion star using an XMM-Newton observation
Armin Nabizadeh, Solen Balman
We present the X-ray analysis of dwarf nova EY Cyg using the 45 ks \textit{XMM-Newton} observatory archival data obtained in quiescence. We find orbital modulations in X-rays. We s…
NuSTAR observations of the wind-fed X-ray pulsar GX 301--2 during an unusual spin-up event
Armin Nabizadeh, Juhani Mönkkönen, Sergey S. Tsygankov +3
We report on \textit{NuSTAR} observations of the well-known wind-accreting X-ray pulsar \source\ during a strong spin-up episode that took place in January-March 2019. A high lumin…
Properties of the transient X-ray pulsar Swift J1816.7--1613 and its optical companion
Armin Nabizadeh, Sergey S. Tsygankov, Dmitrij I. Karasev +4
We present results of investigation of the poorly studied X-ray pulsar Swift J1816.7--1613 during its transition from the type I outburst to the quiescent state. Our studies are ba…