A5026477675- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Calibration and Measurement Techniques
- Optical Polarization and Ellipsometry
- Scientific Research and Discoveries
- Healthcare Systems and Public Health
- Bee Products Chemical Analysis
- Agriculture and Biological Studies
- Circadian rhythm and melatonin
- Human Health and Disease
- Inorganic Fluorides and Related Compounds
- Time Series Analysis and Forecasting
- Neurobiology and Insect Physiology Research
- Gyrotron and Vacuum Electronics Research
- Remote Sensing in Agriculture
- Nuclear and radioactivity studies
- Advanced Optical Sensing Technologies
- Data Visualization and Analytics
- Crystal Structures and Properties
- Advanced Fluorescence Microscopy Techniques
Centre National de la Recherche Scientifique
2021-2024
Université Paris Cité
2021-2024
Université Paris Sciences et Lettres
2021-2024
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2023-2024
Observatoire de Paris
2023-2024
Sorbonne Université
2023-2024
Université de Versailles Saint-Quentin-en-Yvelines
2023-2024
Délégation Paris 7
2024
Lomonosov Moscow State University
2018-2023
Laboratoire AstroParticule et Cosmologie
2022-2023
The origin of ultracompact dwarfs (UCDs), a class compact stellar systems discovered two decades ago, still remains matter debate. Recent discoveries central supermassive black holes in UCDs likely inherited from their massive progenitor galaxies provide support for the tidal stripping hypothesis. At same time, on statistical grounds, some might be representatives high luminosity tail globular cluster function. Here we present detection $3.3^{+1.4}_{-1.2}\times10^6\,M_{\odot}$ hole ($1σ$...
Ultra-diffuse galaxies (UDGs) are spatially extended, low surface brightness stellar systems with regular elliptical-like morphology found in a wide range of environments. Studies the internal dynamics and dark matter content UDGs that would elucidate their formation evolution have been hampered by brightnesses. Here we present resolved velocity profiles, dispersions, ages metallicities for 9 Coma cluster. We use intermediate-resolution spectra obtained Binospec, MMT's new high-throughput...
(Abridged) To understand if the morphology-density and passive-density relations are already established at z>1.5, we study galaxies in 16 confirmed clusters $1.3<z<2.8$ from CARLA survey. Our main finding is that place $z\sim2$. The cluster z = 2.8 shows a similar fraction of ETG as other its densest region. passive fractions depend on local environment mildly galaxy mass. They do not global environment. At lower densities, exhibit than 1. This implies regions influence morphology first,...
The circumstellar envelopes (CSE) of Cepheids are still only poorly characterized despite their potential impact on the distance determination via both period-luminosity relation and parallax-of-pulsation method. This paper aims to investigate Galactic across instability strip in mid-infrared with MATISSE/VLTI order constrain geometry physical nature (gas and/or dust) CSEs. We secured observations eight short- up long-period pulsations L, M, N bands. For each star, we calibrated flux...
Surface brightness--colour relations (SBCRs) are widely used to determine the angular diameters of stars. They in particular Baade-Wesselink (BW) method distance determination Cepheids. However, impact SBCR on BW Cepheids is about 8%, depending choice considered literature. We aim calibrate a precise dedicated using best quality interferometric measurements available as well different photometric bands, including Gaia bands. selected and data literature for seven covering pulsation periods....
To use the period-luminosity relations of Cepheids to derive distances extragalactic Cepheids, it is crucial have reliable estimations luminosity such stars. However, light curves (LCs) are sparsely sampled, which makes interpolation difficult. Our purpose create general templates Cepheid LCs that can be efficiently applied with only a few parameters, while ensuring they in terms resulting mean magnitudes. We also aimed provide adaptable for large variety photometric bands enlarge their...
Abstract We present reprocessed flux-calibrated spectra of 406 stars from the UVES-POP stellar library in wavelength range 320–1025 nm, which can be used for population synthesis. The are provided two versions having spectral resolving power R = 20,000 and 80,000. Raw ESO data archive were re-reduced using latest version UVES reduction pipeline with some additional algorithms that we developed. most significant improvements comparison original release (i) an updated echelle order merging,...
We study the galaxy mass-size relation in 15 spectroscopically confirmed clusters at 1.4 < z 2.8 from CARLA survey. Our span a total stellar mass range 11.3 log( M * c / ⊙ ) 12.6 (with an approximate halo 13.5 ≲ h 14.5). main finding is that cluster passive early-type galaxies (ETGs) ≳ 1.5 with > 10.5 are systematically ≳0.2 − 0.3dex larger (≳3 σ than field ETGs similar redshift and CANDELS The ETG average size evolution slower 1 2 when compared to field. This could be explained by...
We present high resolution H i 21 cm Giant Meterwave Radio Telescope observations of the superthin galaxy FGC 1540 with a spatial 10 arcsec × 8 and spectral 1.73 km s−1 an rms noise 0.9 mJy per beam. obtain its rotation curve as well deprojected radial surface density profile by fitting 3D tilted-ring model directly to data cubes using publicly available software, Fully Automated tirrific. also derived from optical spectroscopy study 6-m BTA telescope Special Astrophysical Observatory...
Context . The application of the parallax-of-pulsation (PoP) technique to determine distances pulsating stars implies use a scaling parameter, namely projection factor ( p -factor), which is required transform disc-integrated radial velocities (RVs) into photospheric expansion velocities. value this parameter poorly known and still debated. Most present applications PoP assume constant -factor. However, it may actually depend on physical parameters each star, as past studies designed...
Context. An inner companion has recently been discovered orbiting the prototype of classical Cepheids, δ Cep, whose orbital parameters are still not fully constrained. Aims. We collected new precise radial velocity measurements Cep in 2019 using HARPS-N spectrograph mounted at Telescopio Nazionale Galileo . Using these measurements, we aimed to improve system. Methods. considered a template available literature as reference for curve pulsation star. then calculated residuals between our...
Low-mass early-type galaxies, including dwarf spheroidals (dSph) and brighter ellipticals (dE), dominate the galaxy population in groups clusters. Recently, an additional of more extended ultradiffuse galaxies (UDGs) has been identified, sparking a discussion on potential morphological evolutionary connections between three classifications. Here, we present first measurements spatially resolved stellar kinematics from deep integrated-light spectra KDG 64 (UGC 5442), large dSph M 81 group....
Ultra-diffuse galaxies (UDGs) are spatially extended, low surface brightness stellar systems with regular elliptical-like morphology found in large numbers galaxy clusters and groups. Studies of the internal dynamics dark matter content UDGs have been hampered by their brightnesses. We identified a sample low-mass early-type post-starburst galaxies, `future UDGs' Coma cluster still populated young stars, which will passively evolve into next 5$-$10 Gyr. collected deep observations for using...
The application of the parallax pulsation (PoP) technique to determine distances pulsating stars implies use a scaling parameter, projection factor (p-factor), required transform disc-integrated radial velocities (RVs) into photospheric expansion velocities. value p-factor is poorly known and debated. Most PoP applications assume constant p-factor. However, it may actually depend on physical parameters each star. We aim calibrate p-factors for RR Lyrae (RRLs) compare them with classical...
The circumstellar envelopes (CSE) of Cepheids are still not well characterized despite their potential impact on distance determination via both the period-luminosity relation and parallax-of-pulsation method. This paper aims to investigate Galactic across instability strip in mid-infrared with MATISSE/VLTI order constrain geometry physical nature (gas and/or dust) CSEs. We secured observations eight from short up long period pulsation, $L$, $M$ $N$-bands. SED analysis mid-IR confirms...
Bocconia is an evergreen plant belonging to the poppy family, and has been used in folk medicine since ancient times. The unique feature of plume cure various diseases can be explained by alkaloids, sanguinarin heleritrin, available its green component. In period 2019 – 2021 Belgorod branch federal state budgetary scientific institution «All-Russian Institute medicinal aromatic plants» field studies were carried out study effect AgroMaster complex fertilizer grade 13-40-13 with microelements...
Observational studies of ultra-diffuse galaxies (UDGs) represent a significant challenge because their very low surface brightnesses. A feasible approach is to identify "future" UDGs when stars are still young. Using data mining, we found 12 such low-mass spatially extended quiescent in the Coma and Abell 2147 clusters SDSS legacy galaxy sample followed them up using new high-throughput Binospec spectrograph at 6.5m MMT. Several exhibit signs recently finished ram pressure stripping. Here...
(Abridged) We study the galaxy mass-size relation in CARLA spectroscopically confirmed clusters at $1.410.5$ are systematically $\gtrsim 0.2-0.3~{\rm dex}$ larger than field ETGs. The passive ETG average size evolution is slower $1
We present preliminary results from our spectroscopic survey of low-luminosity early-type galaxies in the Coma cluster conducted with Binospec spectrograph at 6.5~m MMT. From spatially-resolved profiles internal kinematics and stellar population properties complemented high-resolution images, we placed several dEs on fundamental plane extension available literature data. also discovered unusual kpc-sized kinematically-decoupled cores dwarf galaxies, which had been probably formed before...