21
0
0
Abstracts for the poster presentations
| Name | Affiliation | Abstract |
|---|---|---|
| Bhuvana GR | Gifu University |
Probing the jet-like molecular cloud near the gamma-ray binary LMC P3 The interaction between relativistic jets from compact objects and interstellar hydrogen gas is considered as a potential mechanism for the formation of molecular clouds. However, the underlying astrophysical procedure remains unclear. The compact object in the gamma-ray binary LMC P3 embedded in supernova remnant DEM L241, which is suspected of hosting past relativistic jets, is resolved to be associated with a jet-like molecular cloud in ALMA ACA observation. Intriguingly, the detected jet cloud shows helical substructures, making it an excellent candidate for testing theoretical models, including jet-driven molecular cloud formation and role of helical magnetohydrodynamic instabilities in such jets. We report the results of detailed study of this jet-like molecular cloud carried out using ALMA CO observations to understand the properties and association with the jet from compact object. |
| Yuya Asano | Gifu University |
ALMA Multi–J CO observations of molecular clouds associated with the LMC SNR N63A Shockwaves of Supernova remnant (SNR) play a crucial role in forming galactic structures by heating and compressing the surrounding interstellar medium (ISM). We present compelling evidence of shock-heated molecular clouds associated with the SNR N63A in the Large Magellanic Cloud (LMC). Using 12CO(1–0, 3–2) and 13CO(3–2) line emission data from the Atacama Large Millimeter/Submillimeter Array, we derived the kinetic temperature and H2 number density of ten 13CO detected clouds through the large velocity gradient approximation at a resolution of 3.7 arcseconds (~1.0 pc at the LMC distance). Our analysis reveals that the clouds exhibit kinetic temperatures of ~10–90 K and H2 densities of ~3000–6000 cm-3. Notably, the cloud located within the optical nebulae in the shock-ionized lobe reaches the highest temperature of ~90 K. We also estimated that approximately 0.1 % of the SNR’s energy is transferred to heating the clouds, based on the observed kinetic temperatures and H2 densities by assuming equipartition of energy. Additionally, the post-shock clouds maintain a moderate temperature of ~20 K, likely due to strong UV radiation from a nearby OB association. In this poster, we will discuss the heatin |
| Haruto Inoue | Gifu University |
Observational Study of the Molecular Cloud Associated with the Supernova Remnant RCW 103 Identifying molecular clouds associated with supernova remnants (SNRs) is crucial for understanding the origin of Galactic cosmic rays. RCW 103 is a shell-type SNR with a bright radio continuum and thermal-dominated X-rays. Detecting GeV and TeV gamma rays suggests that cosmic-ray protons are efficiently accelerated. Although the association of molecular clouds has been suggested through several pointings of CO line observations near the shell, their total mass and spatial distribution were not studied (Paron et al. 2006). We conducted new CO and HI studies toward RCW 103 using Mopra and ATCA. We found that CO clouds at -58.7–-43.5 km s-1 show a good spatial correspondence with the X-ray shell, particularly extending from the northwest to the southeast. We also found an expanding motion of the clouds with ΔV~7.5 km s-1 formed by shock waves and/or winds from the progenitor system. In addition, the total energy of cosmic rays Wp was estimated to be ~2.8×1047 erg by adopting the number density of total interstellar protons of ~840 cm-3. This value is more than an order of magnitude lower than the energy predicted for other gamma-ray SNRs. Based on these findings, this poster will discuss the origins of cosmic ray acceleration and thermal plasma in RCW 103. |
| Günay Paylı | Astrophysikalisches Institut und Universitaets-Sternwarte Jena |
Investigation of supernova remnant IC 443 and G189.6+3.3 with LAMOST We present an analysis of the optical emission associated with the supernova remnants (SNRs) G189.6+3.3 and IC 443, based on spectroscopic data obtained with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). All available spectra covering these regions were utilized in the study. Characteristic emission lines of SNRs, including prominent H α, [S ii] and other forbidden lines, were identified and measured from stellar spectra exhibiting low continuum levels (S/N< 10). In the regions northeastern (NE) and east (E) of IC 443, we derive an average [S ii] λλ6716/6731˚A to Hαλ6563 ratio of [S ii]/H α= 0.59±0.12, consistent with moderate shock activity. Within and just beyond the visible boundaries of IC 443, the ratio increases significantly to [S ii]/H α=1.25±0.31, with values reaching up to 1.33 in areas outside the bright filaments, suggesting that the optical extent of IC 443 may be larger than previously estimated. This interpretation aligns with the explosion site inferred from the identification of the pre-supernova binary companion, which is significantly offset from the geometrical center of the SNR. Electron densities (Ne) across the observed region range from 4 to 1257 cm−3, supporting the presence of shock-heated ionized gas. Additionally, we estimate shock velocities, reddening, and interstellar extinction coefficients, and compare these with theoretical predictions. The physical conditions and optical characteristics of the environments surrounding SNR G189.6+3.3 and IC 443 are discussed in detail. |
| Kenta Tatsumi | Konan University |
Evolution of Supernova Remnant Interacting with Turbulent Molecular Cloud: Towards Understanding Cosmic-ray Acceleration Efficiency of RXJ1713 The interaction between SNR and molecular clouds significantly influences SNR evolution by enhancing particle acceleration through turbulent magnetic fields and by boosting X-ray and gamma-ray emission. In the case of SNR RXJ1713.7-3946, the total energy of cosmic-ray protons is estimated to be ~10⁴⁸ erg, which is an order of magnitude lower than expected, if we assume 100% volume filling factor of molecular gas. However, massive stars often leave clumpy molecular structures with low volume filling factors prior to supernovae. Using MHD simulations, we show that when the filling factor exceeds ~10%, the SNR shock speed drops below observed values indicating that the filling factor of RXJ1713 can be much smaller than 10%. |
| Xihui Zhao | Institute for Advanced Study, Tsinghua University |
A New Hydrodynamic Cosmic-Ray Module in ATHENA++ Cosmic rays (CRs) are a dynamically important component in the life cycle of galaxies. Within the interstellar medium (ISM), CRs play an active role by providing additional ionization, influencing gas dynamics, and driving large-scale galactic winds. However, modeling their impact on ISM scales remains a significant challenge due to the inherently multi-scale nature of the problem. While hydrodynamic descriptions of CRs—particularly two-moment numerical schemes—have significantly advanced our understanding, existing implementations still face limitations. These include the incomplete treatment of microphysical transport processes and limited extensibility to diverse regimes, such as self-confinement driven by CR pressure anisotropy. In this work, we derive a two-moment formulation for CR hydrodynamics from first principles, which self-consistently incorporates arbitrary configurations of Alfvén-wave-mediated transport. This framework is designed to flexibly integrate additional physics, such as CR pressure anisotropy. We implement the model in the ATHENA++ code, introducing tailored numerical methods to enhance stability and accuracy. Our approach provides a robust foundation for future comprehensive studies of CR feedback in the ISM and broader astrophysical environments. |
| Susmita Barman | United Arab Emirates University | Impact of Massive star feedback in the Magellanic Clouds We investigate the impact of massive stellar radiation on the interstellar medium (ISM) in star forming regions of the Large and Small Magellanic Clouds (LMC and SMC). Using multiwavelength observations, we analyze how ionizing photons and stellar winds shape molecular clouds, trigger or suppress star formation, and generate high-excitation emission. The low-metallicity environments of the LMC and SMC provide unique insights into feedback processes under conditions unlike those in the Milky Way. Our results highlight the critical role of stellar feedback in regulating cloud structures and star formation in metal-poor galaxies. |
| TK Chan | the Chinese University of Hong Kong |
Simulating HII regions with radiation hydrodynamics and non-equilibrium thermo-chemistry network HII regions are hot energetic regions photo-ionized by new massive stars. They inject new materials and energy into galaxies, and thus regulate galaxy growths. Ongoing and upcoming instruments, e.g. James Webb Space Telescope, Multi Unit Spectroscopic Explorer, Local Volume Mapper, and Affordable Multiple Aperture Spectroscopy Explorer, will provide unprecedented spatially and spectrally resolved HII region observations. To analyse and interpret these observations, we develop a novel simulation pipeline to capture 3D radiation hydrodynamics with comprehensive non-equilibrium thermo-chemistry and dust. We simulate HII regions in an inhomogeneous medium and generate mock observations. By comparing these with real data and diagnosis, we will improve and refine our theoretical models of the interstellar medium. |
| Guan-Hong Li | National Taiwan University |
Formation and Energetics of Supergiant Shell. I. The Simple SGS LMC 1 Supergiant shells (SGSs) are the largest interstellar structures in galaxies and inject hot enriched gas into galactic halos. They commonly exist in disk galaxies and are most likely produced by stellar energy feedback. Only in the Large Magellanic Cloud (LMC) can stars be resolved easily to quantitatively test whether stellar energy feedback is adequate to form SGS. We have chosen to start with SGS LMC 1, the smallest SGS in the LMC and it encompasses an extended OB association LH15. The Gaia EDR3 photometric data of the OB association LH15 inside SGS LMC 1 are used to construct color–magnitude diagrams, and stellar evolutionary tracks and isochrones are used to assess stellar masses and ages. The observed present-day mass function is compared with the Salpeter initial mass function to estimate the number of massive stars that have exploded as supernovae. Their total stellar wind mechanical energy and supernova explosion energy input amounts to (57 ± 12) × 10^51 erg. For the gas components of SGS LMC 1, ATCA+Parkes H I data are used to determine the total mass and kinetic energy in the H I shell, MCELS Hα image is used to determine the ionized gas mass and kinetic energy, adopting the H I expansion velocity, and ROSAT X-ray observations are used to estimate the thermal energy in the SGS interior. The sum of the kinetic and thermal energies in the three layers is estimated to be (59 ± 5) × 10^51 erg. Thus, the stellar energy feedback from LH15 appears adequate to power the formation of SGS LMC 1. The radial age gradient in LH15 and the young stellar objects along the outer periphery indicate a progression of star formation, which might be a crucial factor for an SGS to grow to its large size. |
| Yi Chiao Su | Department of Physics, National Sun Yat-Sen University |
Formation and Energetics of Supergiant Shell. II. The Simple SGS LMC 6 Among the 9 supergiant shells (SGSs) and SGS candidates in the Large Magellanic Cloud (LMC), LMC 1 and LMC 6 are the two smallest (600-700 pc in diameter) and have the most coherent shell structures. Both exhibit an ionized gas shell inside an expanding neutral HI shell. However, there is a striking contrast between their stellar contents: SGS LMC 1 encompasses a recognizable OB association LH15 that stretches from its shell center to its southeast shell rim, while SGS LMC6 has two compact OB associations in HII regions on its shell rim, but no recognizable OB association in its shell center. The OB associations LH11 and LH12 along the SGS LMC 6 shell rim originate from recent episodes of star formation likely triggered by the expansion of the SGS. Thus we analyze the stellar population interior to the SGS LMC 6 to estimate the stellar energy feedback and whether this energy is adequate to power the formation of SGS LMC 6. Following the methodology developed by Li et al. (2025, AJ, 169:283) for the SGS LMC 1, we use the Gaia EDR3 photometric data to construct color-magnitude diagrams (CMDs) of the stellar population within SGS LMC 6 interior, and use stellar evolutionary tracks and isochrones to assess stellar masses and ages. The observed present-day mass function will be compared with the Salpeter initial mass function to estimate the number of stars that have exploded as supernovae. The estimated stellar energy input compared with the observed kinetic and thermal energies in the SGS allows us to determine whether the stellar energy feedback is adequate for the formation of SGS LMC 6. This poster reports the results of this work. |
| Ryan Chiu | National Sun Yat-sen University |
Formation and Energetics of Supergiant Shell. III. Colliding SGS LMC 5 Two supergiant shells (SGSs) in the Large Magellanic Clouds appear to have collided. Of these two SGSs, SGS LMC 4 is the largest with a dimension of 1400 pc x 1000 pc, and SGS LMC 5 is only 800 pc in diameter. In this paper we analyze the stellar population and energetics of the interstellar gas of SGS LMC 5, and probe the impact of collision with SGS LMC 4 on the star formation and shell evolution of SGS LMC 5. Following the methodology by Li et al. (2025, AJ, 169:283), we use Gaia Early Data Release 3 (EDR3) photometric data to construct color–magnitude diagrams of the stellar population within SGS LMC 5 interior as well as the OB associations along its shell rim. Stellar evolutionary tracks and isochrones are employed to estimate stellar masses and ages. By comparing the present-day mass function with Salpeter’s initial mass function, we can estimate the number of massive stars that have undergone supernova explosions, allowing us to evaluate the combined energy input from stellar winds and supernovae. The flux-calibrated MCELS Hα image is used to determine the mass and kinetic energy of the ionized gas, and ATCA+Parkes H I data are used to calculate the total mass and energy in the H I shell. These analyses enable us to investigate the star formation history in SGS LMC 5 and how it is impacted by the collision between SGS LMC5 and SGS LMC 4. The results of this work will be reported in this poster. |
| Kota Kobayashi | Nagoya University |
The Destruction of Molecular Clouds by Expanding HII Regions and Resulting Star Formation Efficiencies H II regions formed by massive stars significantly affect the structure of the circumstellar medium, potentially quenching further star formation. Their expansion is strongly influenced by the density structure of the ambient gas and the spectra of radiation from multiple stars, making it essential to account for the multidimensional distribution of gas and stellar sources. In this study, we perform three-dimensional radiation hydrodynamics simulations to investigate radiative feedback from massive star formation. Our results suggest that the efficiency of radiative feedback varies depending on the clustering of massive stars. We discuss the implications of these findings for molecular cloud destruction and resulting star formation efficiency in realistic star-forming environments. |
| Naofumi Fukaya | Nagoya University |
1000 au-scale filamentary structures and cluster formation in Corona Australis revealed with ALMA The fragmentation process of molecular filaments to achieve high stellar densities is still an open question. We analyzed ALMA data of the Corona Australis (CrA) Molecular Cloud, a cluster-forming region, to solve this question. The ALMA ACA large mosaic data show a network of ~100 thin filamentary structures (width ~1300 au) in the central 0.4 pc^2 area in the cloud. Their typical line mass is only a few Msun/pc, but the ALMA 12m array data show that the most massive filament (~9 Msun/pc) contains 4 protostars with a typical spacing of ~1000 au along its crest, indicating the necessity of continuous mass accretion onto the filament. The CrA cloud is located on the edges of two HI shells, and the associated young stars show outward motion from the center of HI shells. These results suggest filaments and active star formation induced by external compression. |
| Javiera Salinas | Universidad Nacional Autónoma de México | Revealing dense gas kinematics in the G012.80 protocluster We study the dense N2H+ (1-0) gas in the nearby and massive (protocluster G012, observed as part of the ALMA-IMF LP. We model the full line emission with 2 velocity components. In the PV diagrams, we observe zig-zag and twisting velocity structures in the dense gas. We calculate velocity gradients in two filamentary sub-regions (R1 & R2) that differ in their PV diagrams: R1 exhibits ~ helical feature potentially associated with filament rotation (timescale of ~ 0.1 Myr) as well as low core counts, while R2 presents compact velocities, likely related to the collapse. R2 forms more cores per Myr (SRF~72 Msun/Myr) at double the efficiency of R1 (SFR~24 Msun/Myr). We propose that R1 is younger than the R2 filament. G12 thus contains massive filaments in different evolutionary stages. |
| Ryo Igarashi | Niigata University | Grain Size Evolution in an Extended Two-Size Approximation Model In this presentation, we introduce a dust evolution model that extends the two-size approximation by Hirashita (2015) to a two-phase medium, consisting of hot and cold gas. Dust plays a critical role in galaxy evolution by promoting star formation through processes such as molecular formation on grain surfaces, radiative cooling, and UV shielding. It also affects the observed spectral properties of galaxies, with its influence strongly dependent on dust size and composition. While a full calculation of the dust size distribution is ideal, it is computationally expensive. However, the essential behavior can be captured using a two-size approximation with small and large grains, which we adopt as a first-order approach. Our results show that when the star formation timescale is short, the small grain fraction rapidly increases in the early stages and remains dominant afterward. This trend may occur in environments with intense star formation, such as in early galaxies, and has significant implications for understanding galaxy evolution. |
| Chuan-Yung Lin | Department of Physics, National Sun Yat-sen University |
The 200–400 GHz Survey for Dust Properties in the Class II Disks in the Ophiuchus Molecular Cloud We present a SMA survey of 18 Class II sources in Ophiuchus Molecular Cloud, extending previous spectral index studies from the Taurus-Auriga region. Our observations made 12 independent samples of flux densities over the 200–400 GHz frequency range. By measuring flux densities across multiple frequency bands, we derive α200`300GHz to investigate dust optical depth and grain growth properties. Recent studies suggest that most Taurus disks exhibit α ≈ 2.0, indicating that their millimeter emission is dominated by optically thick (τ ≳ 5) dust thermal radiation. If this trend holds in Ophiuchus, it implies that some previous works that were based on the optically thin assumption thus might have underestimated optical depths by at least one order of magnitude. Assuming DSHARP dust opacities, this corresponds to underestimates of dust masses by a similar factor. Intriguingly, our primarily results revealed that the spectral indices of Ophiuchus disks fall within a similar range to those in Taurus, supporting the hypothesis that dust evolution is regulated by optical depth effects rather than grain size variations alone. Population synthesis modeling will be performed to constrain maximum grain sizes (amax) and dust temperatures (Tdust), with initial estimates suggesting that dust growth beyond the water snowline remains limited by the bouncing/fragmentation barriers. The corresponding results of this study will place new constraints on dust evolution models, maximum grain sizes, and the role of optical depth in disk structure, contributing to a broader understanding of planet formation across different star-forming environments. |
| Shusuke Utsumi | Nagoya University |
On the Origin of Jupiter-mass Binary Objects (JuMBOs): An Application of Our New Smoothed Particle Radiation Hydrodynamics Recently Fu et al. (2025) proposed a novel mechanism for forming Jupiter Mass Binary Objects (JuMBOs), suggesting that gravitational collapse of filamentary gas structures, created through tidal interactions between adjacent circumstellar disks, leads to JuMBO formation. However, their hydrodynamics simulations assumed isothermality and did not incorporate compressional heating and radiative cooling that is expected to determine the fragmentation scale. In this presentation, we introduce a new numerical method that implements precise radiative transfer modules into Smoothed Particle Hydrodynamics method, and investigate JuMBO formation mechanisms. |
| Yamato MATSUZUKI | Nagoya University |
Observational Study of Molecular Cloud Formation Through Multiphase Decomposition of Atomic Hydrogen Neutral hydrogen (HI) clouds, the parent of molecular clouds, comprise a multiphase medium including the warm neutral medium, cold neutral medium (CNM), and a unstable phase connecting them. Molecular hydrogen forms in the CNM. We investigated the high Galactic latitude region HLCG92-35 using HI emission line data from the Arecibo telescope. Given multiple velocity components in the HI emission, we used ROHSA, a multi-Gaussian decomposition method, to separate into three phases. The CNM shows clumpy structures, interpreted as signs of thermal instability. A substantial fraction of thermally unstable gas was identified. In regions where CO emission is detected, CNM at corresponding velocities is relatively abundant, suggesting these components play a key role in molecular cloud formation. |
| Takeru MURASE | Gifu University |
Enabling Precise Studies of the ISM: Full Reprocessing of the FUGIN Galactic Plane Survey The FUGIN (FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope) project is one of the legacy surveys conducted with the Nobeyama 45-m telescope. It provides CO (J=1–0) isotope maps of the Galactic plane with a high angular resolution of 20 arcsec. The mapped region covers the first quadrant (10° < l < 50°, |b| ≤ 1°). However, the currently published data contain artificial stripe-like structures, which have made it difficult to study the interstellar gas at the original-angular resolution. In this study, we present that these artificial structures have been successfully and efficiently removed through an improved data reduction process. The re-reduction of all FUGIN-observed areas has been completed for both the 12CO and 13CO data. |
| Sougata Sarkar | Indian Institute of Science |
WNM & CNM Identification in GARCIA Galaxies Using The Gaussian Mixture Model (GMM), an Unsupervised Machine Learning Method Multiple thermal phases of gas are known to exist in Interstellar Medium. HI gas can manifest in distinct thermal states due to various heating and cooling processes in the ISM caused by the feedback from massive stars during their lifetime and after death (supernovae). Molecular clouds comprising molecular hydrogen (H2) represent the coldest phase of the ISM, with temperatures ranging from 10-20 K. The Cold Neutral Medium (CNM) comprising atomic hydrogen (HI) has a temperature range of 20-100 K. In contrast, the Warm Neutral Medium (WNM) has much higher temperatures ranging from 5000-8000 K and much lower densities when compared to the CNM. Given their distinct temperature ranges, both CNM and WNM leave their unique imprints on the hydrogen line spectra. Narrow spectral widths are associated with CNM, while wide spectral widths are associated with WNM, making their identification possible. Previous studies used the Gaussian decomposition method to differentiate between WNM and CNM by decomposing the H I line-of-sight velocity profiles into multiple Gaussians and correlating them to kinetic temperatures. Several limitations are associated with using this technique: reduced sensitivity with SNR, inability to perform region-wise averaging without prior knowledge of cold and warm regions and high uncertainties associated with the identified components. To this end, we have used the Gaussian Mixture Model (GMM), which is an automated technique to identify distinct physical structures in the ISM to distinguish between the warm and cold ISM phases of GARCIA (GMRT archive atomic gas survey) galaxies. GMM, when applied to a velocity-resolved dataset, finds clusters of spectra that have similar profiles to each other. This provides prior knowledge of regions with similar spectral characteristics, allowing us to average the spectra within these regions to achieve a higher signal-to-noise ratio (SNR). Consequently, performing Gaussian decomposition on these averaged spectra and extracting the proportion of cold gas becomes more accurate compared to previous methods. |
| Tao Jing | Department of Astronomy, Tsinghua University |
On the Origin of Quenched but Gas-rich Regions at Kiloparsec Scales in Nearby Galaxies We use resolved spectroscopy from MaNGA to investigate the significance of both local and global properties of galaxies to the cessation of star formation at kpc scales. Quenched regions are identified from a sample of isolated disk galaxies by a single-parameter criterion Dn(4000) - log EW(Hα) > 1.6 - log 2 = 1.3, and are divided into gas-rich quenched regions (GRQRs) and gas-poor quenched regions according to the surface density of cold gas (Σgas). Both types of quenched regions tend to be hosted by non-AGN galaxies with relatively high mass (M* > 10^10 Msun) and red colors (NUV − r > 3). They span wide ranges in other properties including structural parameters that are similar to the parent sample, indicating that the conditions responsible for quenching in gas-rich regions are largely independent of the global properties of galaxies. We train random forest classifiers and regressors for predicting quenching in our sample with 15 local/global properties. Σ* is the most important property for quenching, especially for GRQRs. These results strongly indicate the important roles of low-mass hot evolved stars, which are numerous and long-lived in quenched regions and can provide substantial radiation pressure to support the surrounding gas against gravitational collapse. The different feature importance for quenching, as found previously by A. F. L. Bluck et al., is partly due to the different definitions of quenched regions, particularly the different requirements on EW(Hα). |
| Fumika Demachi | Nagoya university |
An evolutionary trend of the giant molecular clouds in the Antennae Galaxies Giant molecular clouds (GMCs) are the main site of star formation (SF) in galaxies. To unveil the GMC evolution under the Starburst, we focus on one of the nearest interacting galaxies, the Antennae Galaxies (AGs). We identify GMCs and HII regions from position-position-velocity data of 12CO(1-0) by ALMA and Hα by VLT with MUSE, respectively, then classify GMCs into three Types, corresponding to the evolutionary sequences, based on the Hα luminosities of the associated HII regions. As a result, AGs host an order of magnitude more massive GMCs and luminous HII regions than other main-sequence galaxies. The <5 Myr star clusters are associated with massive GMCs in the overlap region, while >5 Myr clusters are not associated. This is consistent with the simulated interacting motion of AGs that they collided 6 Myr ago (Renaud et al., 2015), and we interpret it as ongoing cluster formation and evolution of GMCs. |
| Tomonari Michiyama | Shunan University |
ALMA and JWST Evidence for Cloud-Cloud Collision Triggering Super Star Cluster Formation in the Antennae Overlap Region We present high-resolution (~0.12 arcsec, ~14 pc) ALMA CO(1–0) observations of young super star clusters (SSCs) in the Antennae overlap region. The data reveal two CO(1-0) components with distinct velocities (~50 km/s apart), each with a different morphology: a U-shaped structure likely formed by ram pressure and a hub–filament structure. These clouds are likely undergoing a collision, and at their interface, we detect 100 GHz continuum dominated by free–free radiation, consistent with ionizing photons from massive stars. JWST (NIRCam and MIRI) infrared imaging shows emission along the inferred collision interface. These results provide multi-wavelength evidence that cloud–cloud collisions trigger SSC formation in the Antennae. |
| Kathleen K.L. Charlton | University of Cape Town |
Tidal intereactions with HI-absorption at z=0.35: results from MIGHTEE-HI We present a targeted search for 21cm HI in absorption in galaxies up to z = 0.48, using HI and continuum data from the MIGHTEE survey in the COSMOS field. MeerKAT’s excellent sensitivity allows us to probe HI absorption against background sources with continuum fluxes far fainter than before (S_1.24GHz ~0.1 mJy). We investigate how large-scale gas flows affect the ISM, regulate star formation, and fuel AGN. We will present 3 associated-HI absorption candidates, two of which are against resolved FR-II galaxies, allowing us to see complex large-scale HI dynamics and potential tidal interactions at redshifts of z0.35 for the first time. We use these results as a probe of the current limitations of low luminosity HI absorption studies and look to what will be achieved with the SKA. |
| Ren Matsusaka | University of Tokyo |
Off-plane molecular gas in the edge-on galaxy NGC 4565 with the Nobeyama 45-m telescope Understanding how gas is supplied to keep star formation is key to studying galaxy evolution. We performed wide-field, high-sensitivity 12CO observations of the edge-on galaxy NGC 4565 using the Nobeyama 45-m telescope. The mapping covers 20′×4′ with a spatial resolution of ~900 pc. This survey reveals molecular gas extending to ~1 kpc above the galactic plane. It provides the most detailed view to date of off-plane molecular gas distribution on a sub-kpc scale, highlighting the vertical structure and disk-halo interaction in a normal spiral galaxy. |
| Przemyslaw Nowaczyk | Astronomical Observatory Institute, Adam Mickiewicz University in Poznań |
Influence of dust on physical properties of early-type galaxies Dust and cold interstellar medium (ISM) play crucial role in galaxy evolution. In particular, dust removal processes are tightly connected to quenching star formation (SF). For a deeper understanding of the large-scale interrelation between dust availability and physical properties, we worked with around 18 000 early-type galaxies (ETGs). We combined multi-wavelength spectral energy distribution modeling with Herschel-based dust classification, in the redshift range of 0.01 < z < 0.32, obtaining a great laboratory to study SF quenching and dust depletion. Acquired results show that dust removal from the ISM lowers star formation rates in ETGs, leaves them with older stellar populations, and is responsible for their departure below the main sequence relation. They confirm the impact that dust and ISM evolution have on the physical properties of ETGs and quenching of SF therein, advancing our understanding of galaxy evolution. |
| Mehbuba Ahmed Mohammed | Space Science and Geospatial Institute (SSGI) |
Chemical abundances of type-2 AGN in different environments The chemical abundance of active galaxies, which host active galactic nuclei (AGN) at their centre, |
| remains poorly studied, most often due to the difficulty of removing the effect of AGN in metallicity | ||
| measurements. In particular, the chemical abundance of active galaxies in different environments, | ||
| including clusters and groups of galaxies, is still unknown. In this work, we use a novel HCm code (HII- | ||
| CHI-mistry) adapted to measure the chemical abundance of type-2 AGN. We measure the oxygen | ||
| abundance (12 + log(O/H)), the nitrogen abundance (log(N/O)), and the ionisation parameter (logU) for ~ | ||
| 12000 type-2 AGN selected from the SDSS survey. We analyse the metallicity properties of type-2 AGNs | ||
| in relation to other properties of AGN host galaxies, such as morphology, stellar mass and star formation | ||
| rate (SFR), and in terms of the environment. In addition, for galaxies in groups and clusters, we study the | ||
| metallicity properties in relation to the properties of the galaxy groups/clusters (e.g., the cluster-centric | ||
| distance and the number of galaxies in the group/cluster). We do not observe a clear and strong mass- | ||
| metallicity relation, although, we do observe that in groups and clusters, the 12 + log(O/H) abundance is | ||
| higher in galaxies with higher stellar mass. We find that the 12 + log(O/H) abundance decreases with | ||
| increasing SFR in all environments. We do not find a fundamental plane of type-2 AGN, suggesting more | ||
| complex scenarios in the behaviour of stellar mass, SFR and metallicity when AGN are present, | ||
| compared to pure star-forming galaxies. We find that type-2 AGN hosts, both early- and late-type, have | ||
| on average higher 12 + log(O/H) abundances in groups and clusters compared to field galaxies, | ||
| independent of redshift. Our results indicate that, although type-2 AGN in groups and clusters have on | ||
| average higher metallicities for a given stellar mass, neither simple group or cluster membership nor | ||
| cosmic-centric distance seems to drive this effect. Finally, with this work, we provide the largest | ||
| catalogue of chemical abundances of type-2 AGN to date. |