A5051536296- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Bacteriophages and microbial interactions
- Time Series Analysis and Forecasting
- Solid-state spectroscopy and crystallography
- Astro and Planetary Science
- Black Holes and Theoretical Physics
- Lightning and Electromagnetic Phenomena
- Advanced Computational Techniques and Applications
- Liquid Crystal Research Advancements
- Nonlinear Optical Materials Research
- Advanced X-ray Imaging Techniques
- Advanced Decision-Making Techniques
- Plant Water Relations and Carbon Dynamics
- Ionosphere and magnetosphere dynamics
- Aquaculture disease management and microbiota
Beijing Normal University
2009-2024
China Southern Power Grid (China)
2024
Istituto Nazionale di Fisica Nucleare, Sezione di Torino
2015-2018
University of Turin
2015-2018
Istituto Nazionale di Fisica Nucleare
2015
Kunming University of Science and Technology
2015
Trieste Astronomical Observatory
2011
We propose a novel method to constrain turbulence and bulk motions in massive galaxies, groups clusters, exploring both simulations observations. As emerged the recent picture of top-down multiphase condensation, hot gaseous halos are tightly linked all other phases terms cospatiality thermodynamics. While (10^7 K) perturbed by subsonic turbulence, warm (10^4 ionized neutral filaments condense out turbulent eddies. The peaks into cold molecular clouds (< 100 raining core via chaotic...
Abstract The Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is a pair of microsatellites (i.e., GECAM-A and GECAM-B) dedicated to monitoring gamma-ray transients including the high-energy electromagnetic counterparts gravitational waves, such as bursts, soft repeaters, solar flares, terrestrial flashes. Since launch in 2020 December, GECAM-B has detected hundreds astronomical events. For these localization key for burst identification classification well...
We present a new deep spectroscopic catalogue for Abell 85, within 3.0 $\times$ 2.6 Mpc$^2$ and down to $M_{r} \sim M_{r}^* +6$. Using the Visible Multi-Object Spectrograph at Very Large Telescope (VIMOS@VLT) AutoFiber 2 William Herschel (AF2@WHT), we obtained almost 1,430 redshifts galaxies with $m_r \leq 21$ mag $\langle \mu_{e,r} \rangle 24$ arcsec$^{-2}$. These redshifts, together SDSS-DR6 NED information, result in 460 confirmed cluster members. This dataset allows study of luminosity...
Context. The ubiquitous presence of the Fe line complex in X-ray spectra galaxy clusters offers possibility measuring their redshift without resorting to spectroscopic follow-up observations. In practice, blind search is a difficult task and affected not only by limited S/N (particularly at high redshift), but also several systematic errors, associated with varying abundance values, ICM temperature gradients, instrumental characteristics.
Abstract To investigate the dynamics of galaxy cluster A2142, we compile an extended catalog 2239 spectroscopic redshifts sources, including 237 newly measured redshifts, within 30 arcmin from center. With σ -plateau algorithm caustic method, identify 868 members and a number substructures in distribution both outskirts, out to ∼3.5 Mpc center, central region. In one substructure overlaps falling clump gas previously identified X-ray band. These suggest presence multiple minor mergers, which...
We propose a strategy to search for bulk motions in the intracluster medium (ICM) of merging clusters based on Chandra CCD data. Our goal is derive robust measurements average redshift projected ICM regions obtained from centroid Kα line emission. thoroughly explore effect unknown temperature structure along sight accurately evaluate systematic uncertainties redshift. apply our method "Bullet cluster" (1E 0657-56). directly identify 23 independent basis surface brightness contours, and...
ABSTRACT We search for bulk motions in the intracluster medium (ICM) of massive clusters showing evidence an ongoing or recent major merger with spatially resolved spectroscopy Chandra CCD data. identify a sample six merging >150 ks exposure redshift range 0.1 < z 0.3. By performing X-ray spectral analysis projected ICM regions selected according to their surface brightness, we obtain maps all these clusters. After robust statistical and systematic uncertainties measured X , check...
For the first time, we explore dynamics of central region a galaxy cluster within $r_{500}\sim 600h^{-1}$~kpc from its center by combining optical and X-ray spectroscopy. We use (1) caustic technique that identifies substructures their members with spectroscopic data, (2) redshift fitting procedure estimates distribution intracluster medium (ICM). spatial distributions galaxies emitting gas to associate regions. When apply this approach Abell 85 (A85), complex dynamical structure A85 emerges...
Abstract Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a space‐borne instrument dedicated to monitoring transients, including Terrestrial Gamma‐ray Flashes (TGFs) and Electron Beams (TEBs). We implemented TGF/TEB search algorithm for GECAM, with which 147 bright TGFs, 2 typical TEBs special TEB‐like events are identified during an effective observation time of ∼9 months. show that, gamma‐ray charged particle detectors, GECAM can effectively identify...
We investigate the power of caustic technique for identifying substructures galaxy clusters from optical redshift data alone. The is designed to estimate mass profile radii well beyond virial radius, where dynamical equilibrium does not hold. Two by-products this are identification cluster members and substructures. test as a substructure detector on two samples 150 mock surveys clusters; extracted large cosmological N-body simulation ΛCDM model have masses in samples. limit our analysis...
Abstract We present a search for nuclear X-ray emission in the brightest cluster galaxies (BCGs) of sample groups and clusters extracted from Chandra archive. The exquisite angular resolution allows us to obtain robust photometry at position BCG, firmly identify unresolved when present, thanks an accurate characterization extended BCG position. consider two redshift bins (0.2 < z 0.3 0.55 0.75) analyze all observed by with exposure time larger than 20 ks. Our samples have 81 BCGs 73 51 49...
We present the results of deep Chandra and XMM-Newton observations a complex merging galaxy cluster Abell 2256 (A2256) that hosts spectacular radio relic (RR). The temperature metallicity maps show clear evidence merger between western subcluster (SC) primary (PC). detect five X-ray surface brightness edges. Three them near center are cold fronts (CFs): CF1 is associated with infalling SC; CF2 located in east PC; CF3 to west PC core. other two edges at outskirts shock (SFs): SF1 RR NW has...
Abstract Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties guiding follow-up observations. Localization based on relative counts different detectors has been widely used all-sky gamma-ray monitors. There are two major methods this count distribution localization: χ 2 minimization method Bayesian method. Here we propose a modified that could take advantage both accuracy simplicity With comprehensive simulations, find our with Poisson...
The cosmic acceleration is one of the most significant cosmological discoveries over last century. two categories explanation are exotic component (dark energy) and modified gravity. We constrain types model by a joint analysis with perturbation growth direct $H(z)$ data. Though minimal $χ^2$ $Λ$CDM almost same as that DGP, in sense consistency we find dark energy ($Λ$CDM) more favored through detailed comparison corresponding parameters fitted expansion
We investigate the spatial distribution of iron in intra-cluster medium a selected sample 41 relaxed clusters redshift range $0.05 < z 1.03$ using {\sl Chandra} archival data. compute azimuthally-averaged, deprojected $Z_{\rm Fe}$ profile each cluster out to $\sim 0.4r_{500}$, and identify peak followed by flatter at larger radii. Due steep gradient both gas density abundance, we find that emission-weighted abundance within $0.2r_{500}$, which entirely includes most cases, is on average...
We present high-resolution (∼1″), 1.5 GHz continuum observations of the brightest cluster galaxies (BCGs) 13 CLASH (Cluster Lensing And Supernova survey with Hubble) clusters at Karl G. Jansky Very Large Array (JVLA). Radio emission is clearly detected and characterized for 11 BCGs, while two them we obtain only upper limits to their radio flux ( mJy 5σ confidence level). also consider five additional whose BCG in FIRST or NVSS. find powers range from spectral indices (defined as slope...
Galaxy clusters present unique advantages for cosmological study. Here we collect a new sample of 10 lensing galaxy with X-ray observations to constrain parameters. The redshifts the lie between 0.1 and 0.6, redshift range their arcs is from 0.4 4.9. These are selected carefully strong gravitational systems which have both satellite optical giant luminous known redshifts. Giant usually appear in central region clusters, where mass can be traced luminosity quite well. Based on theory cluster...
We investigate the properties of cool cores in an optimally selected sample 37 massive and X-ray-bright galaxy clusters, with regular morphologies, observed Chandra. measured density, temperature, abundance radial profiles their intracluster medium (ICM). From these independent quantities, we computed cooling (tcool) free-fall (tff), turbulence (teddy) timescales as a function radius. By requiring profile-crossing condition, tcool=teddy=1, cool-core condensation radius Rccc, within which...
Abstract We investigate the dust-obscured star formation (SF) properties of massive, X-ray-selected galaxy cluster MACS J1931.8−2634 at z = 0.352. Using far-infrared (FIR) imaging in range 100–500 μm obtained with Herschel telescope, we extract 31 sources (2σ) within r ∼ 1 Mpc from brightest (BCG). Among these sources, identify six members for which perform an analysis their spectral energy distributions (SEDs). measure total infrared luminosity (LIR), rate (SFR) and dust temperature. The...
We develop the Blooming Tree Algorithm, a new technique that uses spectroscopic redshift data alone to identify substructures and surrounding groups of galaxy clusters, along with their member galaxies. Based on estimated binding energy pairs, algorithm builds binary tree hierarchically arranges all galaxies in field view. The searches for buds, corresponding gravitational potential minima branches; each bud, combines number galaxies, velocity dispersion average pairwise distance into...
The analysis of light variation M87 can help us understand the disc evolution. In past decade, has experienced several short-term variabilities related to flares. We also find there are year-scale X-ray variations in core M87. Their variability properties similar clumpy-ADAF. By re-analyzing 56 $\it Chandra$ observations from 2007 2019, we distinguish `non-flaring state' `flaring variability. After removing flaring state data, identify 4 gas clumps nucleus and all them be well fitted by...
Abstract We introduce a new kinematic method to investigate the structure of open star clusters. adopt hierarchical clustering algorithm that uses celestial coordinates and proper motions stars in field view cluster estimate proxy pairwise binding energy arrange them binary tree. The substructures their members are identified by trimming tree at two thresholds, according σ -plateau method. Testing on 100 mock catalogs shows that, average, membership clusters is (91.5 ± 3.5)% complete...
Abstract Studying the structures of open clusters is crucial for understanding stellar evolution and galactic dynamics. Based on Gaia DR3 data, we apply hierarchical clustering algorithm to young cluster NGC 6530 group its members into five substructures. By linear tracing with kinematic information their members, find that sub 1 core cluster. It expanding slowly. Sub 2 consists less-bound which began escaping from about 0.78 Myr ago. 3 associated a star-forming region. will merge after 0.72...