A5085617326- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Spectroscopy and Quantum Chemical Studies
- Astro and Planetary Science
- Sesquiterpenes and Asteraceae Studies
- Advanced Thermodynamics and Statistical Mechanics
- Natural product bioactivities and synthesis
- Calibration and Measurement Techniques
- Photonic and Optical Devices
- Photosynthetic Processes and Mechanisms
- Phytochemistry and Biological Activities
- Quantum Information and Cryptography
- Optical Network Technologies
- Scientific Research and Discoveries
- Plant Toxicity and Pharmacological Properties
- Semiconductor Lasers and Optical Devices
- Astrophysical Phenomena and Observations
- HVDC Systems and Fault Protection
- Power System Reliability and Maintenance
University of Oslo
2020-2024
Shiraz University of Medical Sciences
2022
Chalmers University of Technology
2016-2020
Islamic Azad University, Bushehr Branch
2019
Shahid Beheshti University
2016
Institute for Research in Fundamental Sciences
2015
Alzahra University
2015
Concordia University
1997
Universitat de València
1992-1993
Islamic Azad University, Tehran
1991-1992
Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB) when an efficient mass-loss process removes a significant fraction of their initial mass. For most sources, this relies on interplay between convection, stellar pulsations, dust formation. However, predicting history given star from first principles is complex not yet feasible at present. At end AGB, least some experience substantial increase in rate for unknown reasons, leading to creation post-AGB objects...
<ns3:p>Observations at (sub-)millimeter wavelengths offer a complementary perspective on our Sun and other stars, offering significant insights into both the thermal magnetic composition of their chromospheres. Despite fundamental progress in observations Sun, some important aspects require diagnostic capabilities that are not offered by existing observatories. In particular, simultaneous radiation continuum across an extended frequency range would facilitate mapping different layers thus...
Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB), when an efficient mass-loss process removes a significant fraction of their initial mass. A substantial increase in rate at end AGB is observed for least some unknown reasons. This creates post-AGB objects that are completely enshrouded thick dusty envelopes might be associated with binary interactions. We $J=2-1$ line $^{13}$CO, C$^{17}$O, C$^{18}$O Atacama Large Millimeter / submillimeter Array (ALMA)...
Context. This is the first publication from DEATHSTAR project. The overall goal of project to reduce uncertainties observational estimates mass-loss rates evolved stars on Asymptotic Giant Branch (AGB). Aim. aim in this constrain sizes 12 CO emitting region circumstellar envelopes around 42 mostly southern AGB stars, which 21 are M-type and C-type, using Atacama Compact Array (ACA) at Large Millimeter/submillimeter Array. symmetry outflows also investigated. Methods. Line emission J = 2→1...
Ultraviolet (UV) photodissociation of CO controls the abundances and distribution its products. This significantly influences gas-phase chemistry in circumstellar envelope (CSE) around evolved stars. A better understanding outflows also provides a more precise estimate mass-loss rates. We aim to update rate an expanding spherical assuming that interstellar radiation field (ISRF) photons penetrate through envelope. will allow us precisely abundance distributions CSEs used most recent...
Observations at (sub-)millimeter wavelengths offer a complementary perspective on our Sun and other stars, offering significant insights into both the thermal magnetic composition of their chromospheres. Despite fundamental progress in observations Sun, some important aspects require diagnostic capabilities that are not offered by existing observatories. In particular, simultaneously radiation continuum across an extended frequency range would facilitate mapping different layers thus...
<ns3:p>Observations at (sub-)millimeter wavelengths offer a complementary perspective on our Sun and other stars, offering significant insights into both the thermal magnetic composition of their chromospheres. Despite fundamental progress in observations Sun, some important aspects require diagnostic capabilities that are not offered by existing observatories. In particular, simultaneously radiation continuum across an extended frequency range would facilitate mapping different layers thus...
Abstract NGC 5128 (Cen A) is the nearest giant elliptical galaxy and one of brightest extragalactic radio sources in sky, boasting a prominent dust lane jets emanating from its nuclear supermassive black hole. In this paper, we construct star formation history (SFH) two small fields halo 5128: northeastern field (Field 1) at projected distance ∼18.8 kpc center, southern 2) ∼9.9 center. Our method based on identifying long-period variable (LPV) stars that trace their sibling stellar...
Context. The mass loss experienced on the asymptotic giant branch (AGB) at end of lives low- and intermediate-mass stars is widely accepted to rely radiation pressure acting newly formed dust grains. Dust formation happens in extended atmospheres these stars, where density, velocity, temperature distributions are strongly affected by convection, stellar pulsation, heating cooling processes. interaction between processes how that affects growth complex. Hence, characterising empirically...
We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of Local Group spiral galaxy M33 (Triangulum). The main aim was to identify stars in very final stage their evolution, and for which luminosity is more directly related birth mass than numerous less-evolved giant that continue increase luminosity. In this fourth paper series, we present search variable red an almost square degree region comprising most galaxy's disc, carried out with WFCAM instrument...
The nucleosynthesis production of fluorine (F) is still a matter debate. Asymptotic giant branch (AGB) stars are one the main candidates for F production. However, their contribution to total budget not fully known due lack observations. In this paper, we report detection AlF line emission, two carriers in gas-phase outflow evolved stars, towards five nearby oxygen-rich AGB $o$ Ceti, R Leo, IK Tau, Dor, and W Hya. From spatially resolved observations, estimated emitting region with radius...
The mass loss experienced on the asymptotic giant branch (AGB) at end of lives low- and intermediate-mass stars is widely accepted to rely radiation pressure acting dust grains formed in extended AGB atmospheres. interaction convection, stellar pulsation, heating cooling processes cause density, velocity temperature distributions inner regions envelope be complex, making dust-formation process difficult calculate. Hence, characterising atmospheres outflow empirically paramount advance our...
Submillimeter and millimeter wavelengths provide a unique view of the Universe, from gas dust that fills surrounds galaxies to chromosphere our own Sun. Current single-dish facilities have presented tantalising brightest (sub-)mm sources, interferometers provided exquisite resolution necessary analyse details in small fields, but there are still many open questions cannot be answered with current facilities. In this report we summarise science is guiding design Atacama Large Aperture...
In this contribution the CMOS photonics technology (LuxG) developed and commercialized by Luxtera is reviewed. The advantages of integration usage a standard foundry toolset/process/practice are discussed with mention to newly 14Gbps transceiver chip.
Due to their wide wavelength coverage across the millimetre centimetre (mm - cm) range and increased sensitivity, modern interferometric arrays facilitate observations of thermal non-thermal emission from different stellar atmospheric layers. We study spectral energy distribution ($S_{obs}(\nu)$) main sequence stars using archival mm cm data with aim stratification as a function type. The main-sequence significant detection in bands were identified ALMA Science Archive. These complemented...
We present a new high signal-to-noise ratio spectroscopic survey of the Northern hemisphere to probe Local Bubble and its surroundings using λ5780 Å λ5797 diffuse interstellar bands (DIBs). observed 432 sightlines distance 200 pc over duration three years. In this study, we establish correlations with Na i, Ca ii EB-V, for both inside outside Bubble. The show that among all neutral ionized atoms, correlation between is stronger than λ5797, suggesting more associated regions where Ca+...
Context. An activity indicator, which can provide a robust quantitative mapping between the stellar and physical properties of its atmosphere, is important in exploring evolution observed active phenomena across main-sequence stars different spectral types. Common indicators do qualitative correlations with such as T eff rotation period, among others. However, due to large variability their values, even for single star, defining mappings difficult. Millimetre (mm) wavelengths probe...
This paper reviews the CMOS photonics technology developed and commercialized by Luxtera. IC design integration methodologies are highlighted performance of Luxtera's newest 4×14Gbps 4×25Gbps transceiver chips is discussed.
We present the detection of neutral atomic carbon CI( 3 P 1 – 0 ) line emission towards omi Cet. This is first time that CI detected in envelope around an oxygen-rich M-type asymptotic giant branch (AGB) star. also confirm previously tentative V Hya, a carbon-rich AGB As one main photodissociation products parent species circumstellar (CSE) evolved stars, can be used to trace sources ultraviolet (UV) radiation CSEs. The observed flux density Cet reproduced by shell with peak fractional...
The dynamics of energy transfer in Fenna–Matthews–Olson (FMO) light-harvesting complex interacting with a phonon bath is investigated. In this contribution, by considering the as source stochastic noise, new approach proposed. Also, calculating global quantum entanglement and discord, time evolution correlation during process evaluated. effects temperature initial excited state on are studied. It shown, agreement previous results, that increasing gives rise to faster delocalisation FMO...
We present a photometric study of the resolved stellar populations in And IX, closest satellite to M31, metal-poor and low-mass dwarf spheroidal galaxy. estimate distance modulus $24.56_{-0.15}^{+0.05}$ mag based on tip red giant branch (TRGB). By probing variability asymptotic stars (AGB), we star formation history IX. identified 50 long period variables (LPVs) IX using Isaac Newton Telescope (INT) two filters, Sloan $i'$ Harris $V$. In this study, selected LPVs within half-light radii with...