Tuomo Tikkanen
A5030974473- Particle Detector Development and Performance
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- CCD and CMOS Imaging Sensors
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Astrophysics and Cosmic Phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Adaptive optics and wavefront sensing
- Radiation Detection and Scintillator Technologies
- Planetary Science and Exploration
- Astro and Planetary Science
- Advanced Semiconductor Detectors and Materials
- Silicon and Solar Cell Technologies
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Research in Social Sciences
- Educational and Psychological Assessments
- Spectroscopy and Laser Applications
- Child and Adolescent Psychosocial and Emotional Development
- VLSI and Analog Circuit Testing
- Social Capital and Networks
University of Leicester
2008-2025
University of Liverpool
2008-2010
University of Oxford
2007
Helsinki Institute of Physics
1992-2005
University of Helsinki
1992-2005
University of Southampton
2003
Finnish Meteorological Institute
2000-2003
VTT Technical Research Centre of Finland
1988-1990
Abstract The Mid-Infrared Instrument (MIRI) extends the reach of James Webb Space Telescope (JWST) to 28.5 μ m. It provides subarcsecond-resolution imaging, high sensitivity coronagraphy, and spectroscopy at resolutions λ /Δ ∼ 100–3500, with high-resolution mode employing an integral field unit provide spatial data cubes. resulting broad suite capabilities will enable huge advances in studies over this wavelength range. This overview describes history acquiring capability for JWST. discusses...
Abstract We present the ultraviolet luminosity function and an estimate of cosmic star formation rate density at 8 < z 13 derived from deep NIRCam observations taken in parallel with MIRI Deep Survey Hubble Ultra Field (HUDF), covering field 2. Our (40 hr) reach F277W magnitude 30.8 (5 σ ), more than 2 mag deeper JWST public data sets already analyzed to find high-redshift galaxies. select a sample 44 > galaxy candidates based on their dropout nature F115W and/or F150W filters, high...
The nearby Supernova 1987A was accompanied by a burst of neutrino emission, which indicates that compact object (a neutron star or black hole) formed in the explosion. There has been no direct observation this object. In work, we observe supernova remnant with JWST spectroscopy finding narrow infrared emission lines argon and sulphur. line is spatially unresolved blueshifted velocity relative to rest frame. We interpret as gas illuminated source ionizing photons located close center...
The Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) provides measurements over wavelength range 5 to 28.5 μm. MIRI has, within a single "package," four key scientific functions: photometric imaging, coronagraphy, single-source low-spectral resolving power (R ∼ 100) spectroscopy, and medium-resolving 1500 3500) integral field spectroscopy. An associated cooler system maintains at its operating temperature of < 6.7 K. This paper describes driving principles behind...
Abstract We make use of JWST medium-band and broadband NIRCam imaging, along with ultradeep MIRI 5.6 μ m in the Hubble eXtreme Deep Field to identify prominent line emitters at z ≃ 7–8. Out a total 58 galaxies 7–8, we find 18 robust candidates (≃31%) for (H β + [O iii ]) emitters, based on their enhanced fluxes F430M F444W filters, EW 0 +[O ≃87–2100 Å. Among these 16 lie coverage area 12 exhibit clear flux excess m, indicating simultaneous presence H α emission ) ≃200–3000 This is first time...
Using MIRI on-board JWST we present mid-infrared sub-arcsec imaging (MIRIM) and spectroscopy (MRS) of the hyperluminous infrared system SPT0311-58 at z=6.9. observations are compared with existing ALMA far-infrared continuum [CII]158$\mu$m imaging. Even though suggests very high star formation rates (SFR) in eastern (E) western (W) galaxies system, H$\alpha$ line is not detected. This, together detection Pa$\alpha$ line, implies optical nebular extinction lower limits 4.2 3.9 mag (W), even...
We present MIRI/JWST medium-resolution spectroscopy (MRS) and imaging (MIRIM) of the lensed galaxy MACS1149-JD1 at a redshift z = 9.1092 ± 0.0002, when Universe was about 530 Myr old. detect, for first time, spatially resolved H α emission in above nine. The structure emitting gas consists two clumps, S N, carrying 60% 40% total flux, respectively. luminosity implies an instantaneous star-formation rate range 3.2 0.3 5.3 0.4 M ⊙ yr −1 sub-solar solar metallicities. ionizing photon production...
Abstract We present deep James Webb Space Telescope (JWST)/Mid-Infrared Instrument (MIRI) F560W observations of a flux-limited, Atacama Large Millimeter/submillimeter Array (ALMA)-selected sample 28 galaxies at z = 0.5–3.7 in the Hubble Ultra Deep Field (HUDF). The data from MIRI Imaging Survey (MIDIS) reveal stellar structure HUDF rest-frame wavelengths λ > 1 μ m for first time. revise mass estimates using new JWST photometry and find good agreement with pre-JWST analyses; few...
Dusty star-forming galaxies emit most of their light at far-infrared to millimeter wavelengths as star formation is highly obscured. Far-infrared and observations have revealed dust, neutral molecular gas properties. The sensitivity JWST rest-frame optical near-infrared now allows the study stellar ionized content. We investigate spatially resolved distribution kinematics in GN20, a dusty galaxy z = 4.0548. present deep MIRI/MRS integral field spectroscopy emission GN20. detect Pa α , out...
Abstract By using an ultradeep JWST/MIRI image at 5.6 μ m in the Hubble eXtreme Deep Field, we constrain role of strong H α emitters (HAEs) during “cosmic reionization” z ≃ 7–8. Our sample HAEs is comprised young (<35 Myr) galaxies, except for one single galaxy (≈300 Myr), with low stellar masses (≲10 9 M ⊙ ). These show a wide range rest-frame UV continuum slopes ( β ), median value = −2.15 ± 0.21, which broadly correlates mass. We estimate ionizing photon production efficiency ξ ion,0 )...
Abstract We present initial results from JWST NIRSpec integral field unit observations of the nearby supernova SN 1987A. The provide first spatially resolved spectroscopy ejecta and equatorial ring (ER) over 1–5 μ m range. construct 3D emissivity maps [Fe i ] 1.443 line inner He 1.083 reverse shock (RS), where former probes explosion geometry latter traces structure circumstellar medium. also a model for integrated spectrum ejecta. map reveals highly asymmetric morphology resembling broken...
Abstract We study the stellar population properties of 182 spectroscopically confirmed (MUSE/VLT) Ly α emitters (LAEs) and 450 photometrically selected Lyman-break galaxies (LBGs) at z = 2.8–6.7 in Hubble Extreme Deep Field. Leveraging combined power Space Telescope JWST NIRCam MIRI observations, we analyze their rest-frame UV-through-near-IR spectral energy distributions, with playing a crucial role robustly assessing LAEs’ masses ages. Our LAEs are low-mass objects <mml:math...
Abstract The Mercury Imaging X-ray Spectrometer is a highly novel instrument that designed to map Mercury’s elemental composition from orbit at two angular resolutions. By observing the fluorescence X-rays generated when solar-coronal and charged particles interact with surface regolith, MIXS will be able measure atomic of upper ∼10-20 μm on day-side. Through precipitating night-side, also determine dynamic interaction planet’s surrounding space environment. composed complementary elements:...
Luminous infrared galaxies at high redshifts ($z$>4) include extreme starbursts that build their stellar mass over short periods of time (>100 Myr). These are considered to be the progenitors massive quiescent intermediate ($z\sim$2) but structure and buildup is unknown. Here, we present first spatially resolved near-infrared imaging GN20, one most luminous dusty star-forming known date, observed an epoch when Universe was only 1.5 Gyr old. The 5.6$\mu$m image taken with JWST Mid-Infrared...
We combine the deepest X-ray survey from Chandra Deep Field-South (CDF-S) `7-Ms' with mid-infrared (5.6$ \mu m$) image JWST/MIRI Imaging Survey (MIDIS) in Hubble Ultra-Deep Field (HUDF) to study infrared counterparts and point-source emission of 31 sources a median, intrinsic, rest-frame luminosity $\log_{10}(L_{\rm Xc}^{\rm 0.5-7keV})$=42.04$\pm$0.22 erg $\rm s^{-1}$. The sample includes 24 AGN redshift range, as set by detectability, $z \simeq 0.5-3$. Through multi-wavelength morphological...
Abstract This paper presents a new X-ray fluorescence simulation (DigiGREF), designed as digital analogue to the Mercury Imaging Spectrometer (MIXS) ground-reference facility (GREF). MIXS is novel instrument, onboard BepiColombo spacecraft, and requires characterisation of flight-qualification model (FQM) in laboratory setting. DigiGREF first step towards simulating emission detection (XRF), which will eventually allow elemental abundances Mercury’s surface be accurately determined. solves...
We present an estimate of the performance that will be achieved during on-orbit operations JWST mid-infrared instrument, MIRI. The efficiency main imager and spectrometer systems in detecting photons from astronomical target are presented, based on measurements at subsystem instrument-level testing, with end-to-end transmission budget discussed some detail. brightest fluxes can measured without saturating detectors provided. sensitivity for long-duration observations faint sources is...
Abstract We report the discovery of Cerberus, an extremely red object detected with MIRI Deep Imaging Survey (MIDIS) observations in F1000W filter Hubble Ultra Field. The is at signal-to-noise ratio (S/N) ∼ 6, 27 mag, and undetected NIRCam data gathered by JWST Advanced Extragalactic (JADES), fainter than 30.0–30.5 mag 5 σ detection limits individual bands, as well MIDIS F560W ultradeep (∼29 ). Analyzing spectral energy distribution built low-S/N (<5) measurements optical-to-mid-infrared...
Abstract Supernova (SN) 1987A is the nearest supernova in ∼400 yr. Using JWST MIRI Medium Resolution Spectrograph, we spatially resolved ejecta, equatorial ring (ER), and outer rings mid-infrared 12,927 days (35.4 yr) after explosion. The spectra are rich line dust continuum emission, both ejecta ring. broad emission lines (280–380 km s −1 FWHM) that seen from all singly-ionized species originate expanding ER, with properties consistent dense post-shock cooling gas. Narrower (100–170...
We present the ultraviolet luminosity function and an estimate of cosmic star formation rate density at $88$ galaxy candidates based on their dropout nature in F115W and/or F150W filters, a high probability for photometric redshifts, estimated with three different codes, being $z>8$, good fits $χ^2$ calculations, predominant solutions compared to $z<8$ alternatives. find mild evolution from $z\sim13$ $z\sim8$, i.e., only small increase average number $\sim$0.2 dex, while faint-end...
This paper describes a new method for estimating snow albedo satellite retrieval of surface UV irradiance and daily doses over snow‐covered terrains. The is based on combining meteorological analysis data. data exploited in this work are the measured reflectivities Total Ozone Mapping Spectrometer/Nimbus 7 instrument that coincides with European Centre Medium‐Range Weather Forecasts ERA‐15 reanalyzed We compared satellite‐retrieved to ground‐based measurements two Finnish five Canadian...
Dusty star-forming galaxies (DSFGs) at z > 2 have been commonly observed in overdense regions, where the merging processes and large halo masses induce rapid gas accretion, triggering star formation rates (SFRs) up to ∼1000 M ⊙ yr −1 . Despite importance of these DSFGs for understanding early Universe, their stellar distributions, traced by near-infrared (near-IR) emission, had remained spatially unresolved until arrival JWST. In this work, we present, first time, a resolved morphological...
We present the study of one year INTEGRAL data on neutron star low mass X-ray binary GX 5-1.Thanks to excellent angular resolution and sensitivity INTEGRAL, we are able obtain a high quality spectrum 5-1 from ∼5 keV ∼100 keV, for first time without contamination nearby black hole candidate GRS 1758-258 above 20 keV.During our observations, was mostly found in horizontal normal branch its hardness intensity diagram.A clear hard emission is observed ∼30 which exceeds exponential cut-off...