Star formation traced by optical and millimeter hydrogen recombination lines and free-free emissions in the dusty merging galaxy NGC 3256 -- MUSE/VLT and ALMA synergy
Tomonari Michiyama, Daisuke Iono, Kouichiro Nakanishi, Junko Ueda, Toshiki Saito, Takuji Yamashita, Alberto Bolatto, Min Yun
A galaxy-galaxy merger and the subsequent triggering of starburst activity are fundamental processes linked to the morphological transformation of galaxies and the evolution of star formation across the history of the Universe. Both nuclear and disk-wide starbursts are assumed to occur during the merger process. However, quantifying both nuclear and disk-wide star formation activity is non-trivial because the nuclear starburst is dusty in the most active merging starburst galaxies. This paper presents a new approach to this problem: combining hydrogen recombination lines in optical, millimeter, and free-free emission. Using NGC~3256 as a case study, H$β$, H40$α$, and free-free emissions are investigated using the Multi Unit Spectroscopic Explorer at the Very Large Telescope of the European Southern Observatory (MUSE/VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA). The H$β$ image obtained by MUSE identifies star-forming regions outside the nuclear regions, suggesting a disk-wide starburst. In contrast, the H40$α$ image obtained by ALMA identifies a nuclear starburst where optical lines are undetected due to dust extinction ($A_{\rm V}\sim25$). Combining both MUSE and ALMA observations, we conclude that the total SFR is $49\pm2~M_{\odot}$~yr$^{-1}$ and the contributions from nuclear and disk-wide starbursts are $\sim34~\%$ and $\sim66~\%$, respectively. This suggests the dominance of disk-wide star formation in NGC~3256. In addition, pixel-by-pixel analyses for disk-wide star-forming regions suggest that shock gas tracers (e.g., CH$_3$OH) are enhanced where gas depletion time ($τ_{\rm gas}$=$M_{\rm gas}/SFR$) is long. This possibly means that merger-induced shocks regulate disk-wide star formation activities.
The newest generation of integral field unit spectrographs brings three-dimensional mapping of nearby galaxies one step closer. While the focus up to this point was mostly on stars and ionised gas, it is also possible to look at dust in a new, more complete way. Using MUSE science verification observations of NGC 5626, we map the interstellar matter in this dusty lenticular. We use the resolving power of MUSE to measure the optical attenuation with a spectral resolution of 6.25 Å, at physical scales of 0.1-1 kpc. The integrated attenuation curve of NGC 5626 shows a smooth, slightly steeper tha…
We study the ionization and kinematics of the ionized gas in the nuclear region of the barred Seyfert 2 galaxy NGC~5643 using MUSE integral field observations in the framework of the MAGNUM (Measuring Active Galactic Nuclei Under MUSE Microscope) survey. The data were used to identify regions with different ionization conditions and to map the gas density and the dust extinction. We find evidence for a double sided ionization cone, possibly collimated by a dusty structure surrounding the nucleus. At the center of the ionization cone, outflowing ionized gas is revealed as a blueshifted, asymmet…
We report molecular gas mass estimates obtained from a stacking analysis of CO line emission in the ALMA Spectroscopic Survey (ASPECS) using the spectroscopic redshifts from the optical integral field spectroscopic survey by the Multi Unit Spectroscopic Explorer (MUSE) of the {\it Hubble} Ultra Deep Field (HUDF). Stacking was performed on subsets of the sample of galaxies classified by their stellar mass and position relative to the main-sequence relation (on, above, below). Among all the CO emission lines, from \cotwoone to CO(6-5), with redshifts accessible via the ASPECS Band~3 and the MUSE…
We have used the capability of the MUSE instrument to explore the impact of stellar feedback at large scales in Haro 11, a galaxy under extreme starburst condition and one of the first galaxies where Lyman continuum (LyC) has been detected. Using Ha, [OIII] and [OI] emission lines from deep MUSE observations, we have constructed a sequence of velocity-dependent maps of the Ha emission, the state of the ionised gas and a tracer of fast shocks. These allowed us to investigate the ionisation structure of the galaxy in 50 kms^2 bins over a velocity range of -400 to 350 kms. The ionised gas in Haro…
Mapping the molecular gas content of the universe is key to our understanding of the build-up of galaxies over cosmic time. Spectral line scans in deep fields, such as the Hubble Ultra Deep Field (HUDF), provide a unique view on the cold gas content out to high redshift. By conducting `spectroscopy-of-everything', these flux-limited observations are sensitive to the molecular gas in galaxies without preselection, revealing the cold gas content of galaxies that would not be selected in traditional studies. In order to capitalize on the molecular gas observations, knowledge about the physical co…
The purported spiral host galaxy of GRB 020819B at z=0.41 has been seminal in establishing our view of the diversity of long-duration gamma-ray burst environments: optical spectroscopy of this host provided evidence that GRBs can form even at high metallicities, while millimetric observations suggested that GRBs may preferentially form in regions with minimal molecular gas. We report new observations from VLT (MUSE and X-shooter) which demonstrate that the purported host is an unrelated foreground galaxy. The probable radio afterglow is coincident with a compact, highly star-forming, dusty gal…
The early-type galaxy NGC 1316 hosts about 10^7 solar masses of dust within a central radius of 5 kpc. These prominent dust structures are believed to have an external origin, which is also a popular interpretation for other dusty early-type galaxies. We use archival Hubble Space Telescope/ACS data to construct colour maps that delineate the dust pattern in detail, and we compare these data with maps constructed with data from MUSE of the VLT at the European Southern Observatory. Twelve MUSE pointings in wide field mode form a mosaic of the central 3.3'x2.4'. We use the tool PyParadise to fit …
Massive dusty multiphase outflow in local merger shows no sign of slowing on kiloparsec scales
Institute of Theoretical Astrophysics, University of Oslo（奥斯陆大学理论天体物理研究所）；Armagh Observatory and Planetarium（阿马天文台和天文馆）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；Dipartimento di Fisica e Astronomia Augusto Righi, Università degli Studi di Bologna（博洛尼亚大学奥古斯托·里基物理与天文学系）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚空间科学与天体物理学观测站）
Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies -- however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{H2} \sim 2\times 10^{5} ~{\rm M}_{\odot}$) in an outflow from the nuclear star forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionised gas seen in our MUSE TIMER survey.…
AGN Feedback and the Development of Dusty Multiphase Gas in X-ray Emitting Elliptical Galaxies
NASA - Ames Research Center（美国国家航空航天局艾姆斯研究中心）；Dipartimento di Fisica e Astronomia, Universita‘ di Bologna（博洛尼亚大学物理与天文学系）；Istituto Nazionale di Astrofisica - Istituto di Radioastronomia (IRA)（意大利国家天体物理学研究所无线电天文研究所）；University of California Observatories/Lick Observatory（加州大学观测站/利克天文台）；Bay Area Environmental Research Institute（湾区环境研究所）；Departamento de Física, Universidad de Santiago de Chile（智利圣地亚哥大学物理系）；Center for Interdisciplinary Research in Astrophysics and Space Exploration (CIRAS), Universidad de Santiago de Chile（智利圣地亚哥大学天体物理学与空间探索跨学科研究中心）；NASA Ames Research Center - Aviation Systems Division（美国国家航空航天局艾姆斯研究中心航空系统分部）；Crown Consulting, Inc（皇冠咨询公司）；Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学物理、信息学与数学系）
Within the GAs Stripping Phenomena in galaxies with MUSE (GASP) sample, we identified an ongoing 1:1 merger between two galaxies and the consequent formation of a tidal dwarf galaxy (TDG). The system is observed at z = 0.05043 and is part of a poor group. Exploiting the exquisite quality of the MUSE/VLT data, we present the spatially resolved kinematics and physical properties of gas and stars of this object and describe its evolutionary history. An old (luminosity weighted age ~2x10^9yr), gas poor, early-type-like galaxy is merging with a younger (luminosity weighted age ~2.5x10^8 yr), gas ri…
Context. Planet formation is expected to take place in the first million years of a planetary system through various processes, which remain to be tested through observations. Aims. With the recent discovery, using ALMA, of two gaseous spiral arms inside the 120 au cavity and connected to dusty spirals, the famous protoplanetary disk around AB Aurigae presents a strong incentive for investigating the mechanisms that lead to giant planet formation. A candidate protoplanet located inside a spiral arm has already been claimed in an earlier study based on the same ALMA data. Methods. We used SPHER…
Dwarf galaxies are ideal laboratories to study the physics of the interstellar medium (ISM). Emission lines have been widely used to this aim. Retrieving the full information encoded in the spectra is therefore essential. This can be efficiently and reliably done using Machine Learning (ML) algorithms. Here, we apply the ML code GAME to MUSE (Multi Unit Spectroscopic Explorer) and PMAS (Potsdam Multi Aperture Spectrophotometer) Integral Field Unit (IFU) observations of two nearby Blue Compact Galaxies (BCGs): Henize 2-10 and IZw18. We derive spatially resolved maps of several key ISM physical …
We explore the gas morphology and excitation mechanisms of the ionization cones of the Type II Seyfert galaxy NGC~5728. Kinematics derived from near-IR and optical data from the SINFONI and MUSE IFUs on the VLT reveal AGN-driven outflows powered by a super-massive black hole (SMBH) of mass 3.4$\times$10$^2$ M$_\odot$, bolometric luminosity of 1.46$\times$10$^{44}$ erg/s, Eddington ratio 3.3$\times$10$^{-2}$ and an accretion rate of 2.7$\times$10$^2$ M$_\odot$/yr. The symmetric bicone outflows show rapid acceleration to $\pm$250 km/s at $\sim$250 pc, then decelerating to $\sim$130 km/s at 500 p…
NGC 5128 (Centaurus A) is one of the best example to study AGN-feedback in the local Universe. At 13.5 kpc from the galaxy, optical filaments with recent star formation are lying along the radio-jet direction. We used the Atacama Pathfinder EXperiment (APEX) to map the CO(2-1) emission all along the filaments structure. Molecular gas mass of 8.2x10^7 Msun was found over the 4.2 kpc-structure which represents about 3% of the total gas mass of the NGC 5128 cold gas content. Two dusty mostly molecular structures are identified, following the optical filaments. The region corresponds to the crossi…
NGC 3311 is the central galaxy of the Hydra I galaxy cluster. It has a hot interstellar medium and hosts a central dust lane with emission lines. These dust lanes are frequent in elliptical galaxies, but the case of NGC 3311 might be particularly interesting for problems of dust lifetime and the role of cool gas in the central parts. We aim to use archival HST images and MUSE data to investigate the central dust structure of NGC 3311. We used the tool PyParadise to model the stellar population and extract the emission lines. The HST/ACS colour map reveals the known dust structures, but also bl…
This paper presents a detailed analysis of two giant Lyman-alpha (Lya) arcs detected near known galaxies at z=3.038 and z=3.754 lensed by the massive cluster MACS 1206 (z=0.44). The Lya nebulae revealed in deep MUSE observations exhibit a double-peak profile with a dominant red peak that indicates expansion/outflowing motions. One of the arcs stretches over 1' around the Einstein radius of the cluster, resolving the velocity field of the line-emitting gas on kpc scales around a group of three star-forming galaxies of 0.3-1.6L* at z=3.038. The second arc spans 15'' in size, roughly centered aro…
There is growing evidence for physical influence between supermassive black holes and their host galaxies. We present a case study of nearby galaxy NGC 7582, for which we find evidence that galactic substructure plays an important role in affecting the collimation of ionized outflows as well as contributing to the heavy active galactic nucleus (AGN) obscuration. This result contrasts with a simple, small-scale AGN torus model, according to which AGN wind collimation may take place inside the torus itself, at subparsec scale. Using 3D spectroscopy with the MUSE instrument, we probe the kinemati…
Spatially resolved optical and mid-infrared spectroscopy of SDSS1335+0728: implications for the origin of the Ansky event
European Southern Observatory（欧洲南方天文台）；Massachusetts Institute of Technology（麻省理工学院）；Universidad Diego Portales（迭戈·波特莱斯大学）；Black Hole Initiative at Harvard University（哈佛大学黑洞倡议项目）；Universidad de Valparaíso（瓦尔帕莱索大学）；Millennium Nucleus on Transversal Research and Technology to Explore Supermassive Black Holes (TITANS)（探索超大质量黑洞跨学科研究和技术千年核心（TITANS））；Universidad de Tarapacá（塔拉帕卡大学）
