We present high-resolution observations (0".2-1".5) of multiple dense gas tracers, HCN and HCO$^+$ ($J$ = 1-0, 3-2, and 4-3), HNC ($J$ = 1-0), and CS ($J$ = 7-6) lines, toward the nearby luminous infrared galaxy VV 114 with the Atacama Large Millimeter/submillimeter Array. All lines are robustly detected at the central gaseous filamentary structure including the eastern nucleus and the Overlap region, the collision interface of the progenitors. We found that there is no correlation between star formation efficiency and dense gas fraction, indicating that the amount of dense gas does not simply control star formation in VV 114. We predict the presence of more turbulent and diffuse molecular gas clouds around the Overlap region compared to those at the nuclear region assuming a turbulence-regulated star formation model. The intracloud turbulence at the Overlap region might be excited by galaxy-merger-induced shocks, which also explains the enhancement of gas-phase CH$_3$OH abundance previously found there. We also present spatially resolved spectral line energy distributions of HCN and HCO$^+$ for the first time, and derive excitation parameters by assuming optically-thin and local thermodynamic equilibrium (LTE) conditions. The LTE model revealed that warmer, HCO$^+$-poorer molecular gas medium is dominated around the eastern nucleus, harboring an AGN. The HCN abundance is remarkably flat ($\sim$3.5 $\times$ 10$^{-9}$) independently of the various environments within the filament of VV 114 (i.e., AGN, star formation, and shock).
In this work we use seeing-limited SINFONI H- and K-band spectroscopy to analyse the spatially resolved kinematics of the stellar component in the inner r<1-2 kpc of ten nearby (mean z=0.014) LIRGs. We compare the stellar kinematics with those for different gas phases, and analyse the relative effects of using different tracers when estimating dynamical masses. The stellar velocity and velocity dispersion maps are extracted in both near-IR bands by fitting the continuum emission using pPXF while we use the gas kinematics from previous works. We find that the different gas phases have similar k…
In order to pinpoint the place of the (U)LIRGs in the local Universe we examine the properties of a sample of 67 such systems and compare them with those of 268 ETGs and 542 LTGs from the DustPedia database. We make use of multi-wavelength photometric data and the CIGALE SED fitting code to extract their physical parameters. The median SEDs as well as the values of the derived parameters were compared to those of the local ETGs and LTGs. In addition to that, (U)LIRGs were divided into seven classes, according to the merging stage of each system, and variations in the derived parameters were in…
We present the results of surveying [CI] $^3P_1-^3P_0$, $^{12}$CO $J=4-3$, and 630 $μ$m dust continuum emission for 36 nearby ultra/luminous infrared galaxies (U/LIRGs) using the Band 8 receiver mounted on the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array. We describe the survey, observations, data reduction, and results; the main results are as follows. (i) We confirmed that [CI] $^3P_1-^3P_0$ has a linear relationship with both the $^{12}$CO $J=4-3$and 630 $μ$m continuum. (ii) In NGC 6052 and NGC 7679, $^{12}$CO $J=4-3$ was detected but [CI] $^3P_1-^3P_0$ wa…
We present near-infrared integral field spectroscopy of the central kiloparsec of 17 nearby luminous and ultra-luminous infrared galaxies undergoing major mergers. These observations were taken with OSIRIS assisted by the Keck I and II Adaptive Optics systems, providing spatial resolutions of a few tens of parsecs. The resulting kinematic maps reveal gas disks in at least 16 out of 19 nuclei and stellar disks in 11 out of 11 nuclei observed in these galaxy merger systems. In our late-stages mergers, these disks are young (stellar ages $<30$ Myr) and likely formed as gas disks which became unst…
We present the results of a Hubble Space Telescope WFC3 near-UV and ACS/WFC optical study into the star cluster populations of 10 luminous and ultra-luminous infrared galaxies (U/LIRGs) in the Great Observatories All-Sky LIRG Survey (GOALS). Through integrated broadband photometry we have derived ages, masses, and extinctions for a total of 1027 star clusters in galaxies with $d_{L} <$ 110 Mpc in order to avoid issues related to cluster blending. The measured cluster age distribution slope of $dN/dτ\propto τ^{-0.5 +/- 0.2}$ is steeper than what has been observed in lower-luminosity star-formin…
We present a survey of 3 mm molecular lines in IRAS 04296+2923, one of the brightest known molecular-line emitting galaxies, and one of the closest LIRGs. Data are from the Owens Valley and CARMA millimeter interferometers. Species detected at ~<4" resolution include C^18O, HCN, HCO+, HNC, CN, CH_3OH and, tentatively, HNCO. Along with existing CO, ^13CO and radio continuum data, these lines constrain the chemical properties of the inner disk. Dense molecular gas in the nucleus fuels a star formation rate ~>10 M_sun/yr and is traced by lines of HCN, HCO+, HNC, and CN. A correlation between HCN …
We studied the properties of the neutral gas in a sample of 38 local [U]LIRGs, which mainly covers the less explored LIRG luminosity range. This study is based on the analysis of the spatially integrated and spatially resolved spectra of the NaD feature obtained with the VIMOS/VLT-IFS. Analyzing spatially integrated spectra, we find that the contribution of stars to the observed NaD-EWs is generally small (<35%), and therefore this feature is dominated by ISM absorption. After subtracting the stellar contribution, we find that the pure-ISM integrated spectra generally show blueshifted NaD prof…
The SHINING survey (Paper I; Herrera-Camus et al. 2018) offers a great opportunity to study the properties of the ionized and neutral media of galaxies from prototypical starbursts and active galactic nuclei (AGN) to heavily obscured objects. Based on Herschel/PACS observations of the main far-infrared (FIR) fine-structure lines, in this paper we analyze the physical mechanisms behind the observed line deficits in galaxies, the apparent offset of luminous infrared galaxies (LIRGs) from the mass-metallicity relation, and the scaling relations between [CII] 158 $μ$m line emission and star format…
The role of major mergers in galaxy evolution is investigated through a detailed characterization of the stellar populations, ionized gas properties, and star formation rates (SFR) in the early-stage merger LIRGs IC 1623 W and NGC 6090, by analysing optical Integral Field Spectroscopy (IFS) and high resolution HST imaging. The spectra were processed with the Starlight full spectral fitting code, and the emission lines measured in the residual spectra. The results are compared with control non-interacting spiral galaxies from the CALIFA survey. Merger-induced star formation is extended and rece…
This paper presents the spatially resolved star formation history (2D-SFH) of a small sample of four local mergers: the early-stage mergers IC1623, NGC6090, and the Mice, and the more advanced merger NGC2623, by analyzing IFS data from the CALIFA survey and PMAS in LArr mode. Full spectral fitting techniques are applied to the datacubes to obtain the spatially resolved mass growth histories, the time evolution of the star formation rate intensity ($Σ_{SFR}$), and the local specific star formation rate, over three different timescales (30 Myr, 300 Myr, and 1 Gyr). The results are compared with …
We present a first look at the local LIRG, IRAS04296+2923. This barred spiral, overlooked because of its location in the Galactic plane, is among the half dozen closest LIRGs. More IR-luminous than either M82 or the Antennae, it may be the best local example of a nuclear starburst caused by bar-mediated secular evolution. We present Palomar J and Pa beta images, VLA maps from 20-1.3cm, a Keck LWS image at 11.7mic and OVRO CO(1-0) and ^13CO(1-0), and 2.7 mm continuum images. The J-band image shows a symmetric barred spiral. Two bright, compact mid-IR/radio sources in the nucleus comprise a star…
We analyse the star formation (SF) relations in a sample of 16 nearby luminous infrared galaxies (LIRGs) with more than 2800 regions defined on scales of 90 to 500 pc. We used ALMA to map the distribution of the cold molecular gas traced by the J = 2-1 line of CO and archival PaαHST/NICMOS imaging to trace the recent SF. In four objects, we find two different branches in the Kennicutt-Schmidt relation at 90 pc scales, suggesting the existence of a duality in this relation. The two branches correspond to two different dynamical environments within each galaxy. One branch, which corresponds to t…
Mid-infrared molecular hydrogen (H$_2$) emission is a powerful cooling agent in galaxy mergers and in radio galaxies; it is a potential key tracer of gas evolution and energy dissipation associated with mergers, star formation, and accretion onto supermassive black holes. We detect mid-IR H$_2$ line emission in at least one rotational transition in 91\% of the 214 Luminous Infrared Galaxies (LIRGs) observed with Spitzer as part of the Great Observatories All-sky LIRG Survey (GOALS). We use H$_2$ excitation diagrams to estimate the range of masses and temperatures of warm molecular gas in these…
\HI 21-cm Line Properties of the Nearby LIRG IRAS 04296+2923
College of Physics, Guizhou University（贵州大学物理学院）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Guizhou Radio Astronomical Observatory, Guizhou University（贵州大学贵州天文观测站）
We report on a detailed study of the stellar populations and ionized gas properties in the merger LIRG NGC 2623, analysing optical Integral Field Spectroscopy from the CALIFA survey and PMAS LArr, multiwavelength HST imaging, and OSIRIS narrow band H$α$ and [NII]$λ$6584 imaging. The spectra were processed with the STARLIGHT full spectral fitting code, and the results compared with those for two early-stage merger LIRGs (IC 1623 W and NGC 6090), together with CALIFA Sbc/Sc galaxies. We find that NGC 2623 went through two periods of increased star formation (SF), a first and widespread episode, …
We present Atacama Large Millimeter/submillimeter Array observations of multiple CO(1-0), $^{13}$CO(1-0), and C$^{18}$O(1-0) lines and 2.9 mm and 1.3 mm continuum emission toward the nearby interacting luminous infrared galaxy NGC 3110, supplemented with similar spatial resolution H$α$, 1.4GHz continuum, and $K$-band data. We estimate the typical CO-to-H$_2$ conversion factor of 1.7 $M_{\odot}$ (K km s$^{-1}$ pc$^2$)$^{-1}$ within the disk using LTE-based and dust-based H$_2$ column densities, and measure the 1-kpc scale surface densities of star formation rate ($Σ_{\rm SFR}$), super star clus…
Nearby galaxies offer unique laboratories allowing multi-wavelength spatially resolved studies of the interstellar medium, star formation and nuclear activity across a broad range of physical conditions. In particular, detailed studies of individual local luminous infrared galaxies (LIRGs) are crucial for gaining a better understanding of these processes and for developing and testing models that are used to explain statistical studies of large populations of such galaxies at high redshift for which it is currently impossible to reach a sufficient physical resolution. Here, we provide an overv…
We report the detection of two CH$_3$OH lines (J$_K$ = 2$_K$-1$_K$ and 3$_K$-2$_K$) between the progenitor's disks ("Overlap") of the mid-stage merging galaxy VV 114 obtained using the Atacama Large Millimeter/submillimeter Array (ALMA) Band 3 and Band 4. The detected CH$_3$OH emission show an extended filamentary structure (~ 3 kpc) across the progenitor's disks with relatively large velocity width (FWZI ~ 150 km/s). The emission is only significant in the "overlap" and not detected in the two merging nuclei. Assuming optically-thin emission and local thermodynamic equilibrium (LTE), we found…
Nuclear rings are excellent laboratories for studying intense star formation. We present results from a study of nuclear star-forming rings in five nearby normal galaxies from the Star Formation in Radio Survey (SFRS) and four local LIRGs from the Great Observatories All-sky LIRG Survey (GOALS) at sub-kpc resolutions using VLA high-frequency radio continuum observations. We find that nuclear ring star formation (NRSF) contributes 49 - 60\% of the total star formation of the LIRGs, compared to 7 - 40\% for the normal galaxies. We characterize a total of 58 individual star-forming regions in the…
We study for the first time the low-frequency ($\sim$150 MHz) radio brightness distribution of Arp~299 at subarcsecond resolution, tracing in both compact and extended emission regions the local spectral energy distribution (SED) in order to characterize the dominant emission and absorption processes. We analysed the spatially resolved emission of Arp 299 revealed by 150 MHz international baseline Low-Frequency Array (LOFAR) and 1.4, 5.0, and 8.4 GHz Very Large Array (VLA) observations. We present the first subarcsecond (0.4"$\sim$100~pc) image of the whole Arp~299 system at 150~MHz. The high …
ALMA 0.5 kpc Resolution Spatially Resolved Investigations of Nuclear Dense Molecular Gas Properties in Nearby Ultraluminous Infrared Galaxies Based on HCN and HCO$^{+}$ Three Transition Line Data
We present the results of ALMA $\sim$2 mm, $\lesssim$1$''$-resolution observations of ten (ultra)luminous infrared galaxies ([U]LIRGs; infrared luminosity $\gtrsim$ 10$^{11.7}$L$_{\odot}$) at $z <$ 0.15, targeting dense ($>$10$^{4}$ cm$^{-3}$) molecular (HCN, HCO$^{+}$, and HNC J=2-1) and 183 GHz H$_{2}$O 3$_{1,3}$-2$_{2,0}$ emission lines. Higher HCN to HCO$^{+}$ J=2-1 flux ratios are observed in some, but not all, AGN-important ULIRGs than in starburst-classified sources. We detect 183 GHz H$_{2}$O emission in almost all AGN-important ULIRGs, and elevated H$_{2}$O emission is found in two so…
We present results from the Spitzer/IRS spectral mapping observations of 15 local luminous infrared galaxies (LIRGs). In this paper we investigate the spatial variations of the mid-IR emission which includes: fine structure lines, molecular hydrogen lines, polycyclic aromatic features (PAHs), continuum emission and the 9.7um silicate feature. We also compare the nuclear and integrated spectra. We find that the star formation takes place in extended regions (several kpc) as probed by the PAH emission as well as the [NeII] and [NeIII] emissions. The behavior of the integrated PAH emission and 9.…
Spatially Resolved Star Formation relations in local LIRGs along the complete merger sequence
Institute of Astrophysics, Foundation for Research and Technology-Hellas (FORTH)（希腊研究与技术基金会天体物理研究所）；Department of Physics, University of Crete（克里特大学物理系）；School of Sciences, European University Cyprus（塞浦路斯欧洲大学理学院）；National Radio Astronomy Observatory（美国国家射电天文台）；Department of Astronomy, University of Virginia（弗吉尼亚大学天文学系）；European Southern Observatory（欧洲南方天文台）；Joint ALMA Observatory（阿塔卡马大型毫米波/亚毫米波阵列望远镜联合 observatory）；Instituto de Física Fundamental, CSIC（西班牙国家科学研究委员会基础物理研究所）；Observatorio Astronómico Nacional (OAN-IGN)-Observatorio de Madrid（马德里国家天文台）；Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）
Multiphase Analysis of (U)LIRG Nuclear Activity (MAUNA). I. Spatially Resolved Optical Emission-Line Diagnostics
California Institute of Technology（加州理工学院）；University of California, Irvine（加州大学尔湾分校）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉帕鲁纳大学）
VV 655, a dwarf irregular galaxy with HI tidal debris, is a companion to the lenticular luminous infrared galaxy (LIRG) NGC 4418. NGC 4418 stands out among nearby LIRGs due to its dense central concentration of molecular gas and the dusty, bi-polar structures along its minor axis suggestive of a wind driven by a central starburst and possible nuclear activity. We seek to understand the consequences of the ongoing minor interaction between VV 655 and NGC 4418 for the evolution of the LIRG, including the origin of the gas supply responsible for its unusual nuclear properties. We investigate the …
We analyze Chandra X-ray observatory data for a sample of 63 luminous infrared galaxies (LIRGs), sampling the lower-infrared luminosity range of the Great Observatories All-Sky LIRG survey (GOALS), which includes the most luminous infrared selected galaxies in the local universe. X-rays are detected for 84 individual galaxies within the 63 systems, for which arcsecond resolution X-ray images, fluxes, infrared and X-ray luminosities, spectra and radial profiles are presented. Using X-ray and MIR selection criteria, we find AGN in (31$\pm$5)% of the galaxy sample, compared to the (38$\pm$6)% pre…
We present a pilot study of ~ 3" resolution observations of low CO transitions with the Submillimeter Array in three nearby Seyfert galaxies, which are part of the low-luminosity quasi-stellar object (LLQSOs) sample consisting of 99 nearby (z = 0.06) type-1 active galactic nuclei (AGN) taken from the Hamburg/ESO quasi-stellar object (QSO) survey. Two sources were observed in 12CO(2-1) and 13CO(2-1) and the third in 12CO(3-2) and HCO+(4-3). None of the sources is detected in continuum emission. More than 80% of the 12CO detected molecular gas is concentrated within a diameter (FWHM) < 1.8 kpc. …
We present $HST$ narrow-band near-infrared imaging of Pa$α$ and Pa$β$ emission of 48 local Luminous Infrared Galaxies (LIRGs) from the Great Observatories All-Sky LIRG Survey (GOALS). These data allow us to measure the properties of 810 spatially resolved star-forming regions (59 nuclei and 751 extra-nuclear clumps), and directly compare their properties to those found in both local and high-redshift star-forming galaxies. We find that in LIRGs, the star-forming clumps have radii ranging from $\sim90-900$ pc and star formation rates (SFRs) of $\sim1\times10^{-3}$ to 10 M$_\odot$yr$^{-1}$, with…
Dense molecular gas and star formation are correlated in galaxies. The effect of low metallicity on this relationship is crucial for interpreting observations of high redshift galaxies, which have lower metallicities than galaxies today. However, it remains relatively unexplored because dense molecular gas tracers like HCN and HCO+ are faint in low metallicity systems. We present Green Bank Telescope observations of HCN(1-0) and HCO+(1-0) on giant molecular cloud (34pc) scales in the nearby low metallicity ($12+\log({\rm O/H})=8.2$) starburst IC 10 and compare them to those in other galaxies. …
The role of feedback in triggering or quenching star formation and hence driving galaxy evolution can be directly studied with high resolution integral field observations. The manifestation of feedback in shocks is particularly important to examine in galaxy mergers, where violent interactions of gas takes place in the interstellar medium during the course of the galactic collision. As part of our effort to systematically study the local population of luminous infrared galaxies within the Great Observatories All-Sky LIRG Survey, we undertook the Keck OSIRIS AO LIRG Analysis observing campaign …
The interstellar medium is a key ingredient that governs star formation in galaxies. We present a detailed study of the infrared (~ 1-500 micron) spectral energy distributions of a large sample of 193 nearby (z ~ 0.088) luminous infrared galaxies (LIRGs) covering a wide range of evolutionary stages along the merger sequence. The entire sample has been observed uniformly by 2MASS, WISE, Spitzer, and Herschel. We perform multi-component decomposition of the spectra to derive physical parameters of the interstellar medium, including the intensity of the interstellar radiation field and the mass a…
We present an integral field spectroscopic study of radiative shocks in 27 nearby ultraluminous and luminous infrared galaxies (U/LIRGs) from the Great Observatory All-sky LIRG Survey, a subset of the Revised Bright Galaxy Sample. Our analysis of the resolved spectroscopic data from the Wide Field Spectrograph (WiFeS) focuses on determining the detailed properties of the emission line gas, including a careful treatment of multi- component emission line profiles. The resulting information obtained from the spectral fits are used to map the kinematics of the gas, sources of ionizing radiation an…
We present ionized gas properties of 9 local ultra/luminous infrared galaxies (U/LIRGs) at $z <$ 0.04 through IFU observations with KOOLS-IFU on Seimei Telescope. The observed targets are drawn from the Great Observatories All-sky LIRG Survey (GOALS), covering a wide range of merger stages. We successfully detect emission lines such as H$β$, [OIII]$λ$5007, H$α$, [NII]$λλ$6549,6583, and [SII]$λλ$6717,6731 with a spectral resolution of $R$ = 1500-2000, which provides (i) spatially-resolved ($\sim$200-700 pc) moment map of ionized gas and (ii) diagnostics for active galactic nucleus (AGN) within …
Spectrally and spatially resolved (sub)millimeter HCN-to-HCO$^{+}$ flux ratios in nearby ultraluminous infrared galaxies
National Astronomical Observatory of Japan, National Institutes of Natural Sciences (NINS)（日本国立天文台，国立自然科学研究院）；Department of Astronomy, School of Science, Graduate University for Advanced Studies (SOKENDAI)（高级研究大学院大学（SOKENDAI）理学部天文学科）；Toyo University（东洋大学）；Institute of Pure and Applied Sciences, University of Tsukuba（筑波大学纯应用科学研究所）；Tomonaga Center for the History of the Universe, University of Tsukuba（筑波大学丰顺伽宇宙历史中心）；Tsukuba Institute for Advanced Research (TIAR), University of Tsukuba（筑波大学筑波高等研究院 (TIAR)）；Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency（日本宇宙航空研究开发机构宇宙科学研究所）
Luminous infrared galaxies (LIRGs) are enshrouded by a large amount of dust, produced by their active star formation, and it is difficult to measure their activity in the optical wavelength. We have carried out Pa$α$ narrow-band imaging observations of 38 nearby star-forming galaxies including 33 LIRGs listed in $IRAS$ RBGS catalog with the Atacama Near InfraRed camera (ANIR) on the University of Tokyo Atacama Observatory (TAO) 1.0 m telescope (miniTAO). Star formation rates (SFRs) estimated from the Pa$α$ fluxes, corrected for dust extinction using the Balmer Decrement Method (typically $A_V$…
We present new SINFONI near-infrared integral field unit (IFU) spectroscopy and SALT optical long-slit spectroscopy characterising the history of a nearby merging luminous infrared galaxy, dubbed the Bird (IRAS19115-2114). The NIR line-ratio maps of the IFU data-cubes and stellar population fitting of the SALT spectra now allow dating of the star formation (SF) over the triple system uncovered from our previous adaptive optics data. The distinct components separate very clearly in a line-ratio diagnostic diagram. An off-nuclear pure starburst dominates the current SF of the Bird with 60-70% of…
We present an integral field spectroscopic study of two nearby Luminous Infrared Galaxies (LIRGs) that exhibit evidence of widespread shock excitation induced by ongoing merger activity, IC 1623 and NGC 3256. We show the importance of carefully separating excitation due to shocks vs. excitation by HII regions and the usefulness of IFU data in interpreting the complex processes in LIRGs. Our analysis focuses primarily on the emission line gas which is extensive in both systems and is a result of the abundant ongoing star formation as well as widespread LINER-like excitation from shocks. We use …
We use the Herschel/PACS spectrometer to study the global and spatially resolved far-infrared (FIR) fine-structure line emission in a sample of 52 galaxies that constitute the SHINING survey. These galaxies include star-forming, active-galactic nuclei (AGN), and luminous infrared galaxies (LIRGs). We find an increasing number of galaxies (and kiloparsec size regions within galaxies) with low line-to-FIR continuum ratios as a function of increasing FIR luminosity ($L_{\mathrm{FIR}}$), dust infrared color, $L_{\mathrm{FIR}}$ to molecular gas mass ratio ($L_{\mathrm{FIR}}/M_{\mathrm{mol}}$), and …
We present the results of CO(J=3-2) on-the-fly mappings of two nearby non-barred spiral galaxies NGC 628 and NGC 7793 with the Atacama Submillimeter Telescope Experiment at an effective angular resolution of 25". We successfully obtained global distributions of CO(J=3-2) emission over the entire disks at a sub-kpc resolution for both galaxies. We examined the spatially-resolved (sub-kpc) relationship between CO(J=3-2) luminosities (L'CO(3-2)) and infrared (IR) luminosities (LIR) for NGC 628, NGC 7793, and M 83, and compared it with global luminosities of JCMT Nearby Galaxy Legacy Survey sample…
We present spatially resolved BPT mapping of the extended narrow line regions (ENLRs) of seven nearby Seyfert 2 galaxies, using HST narrow band filter imaging. We construct the BPT diagrams using $\leq$ 0.1" resolution emission line images of [O III]$λ$5007, H$α$, [S II]$λ$$λ$6717,6731, and H$β$. By mapping these diagnostic lines according to the BPT classification, we dissect the ENLR into Seyfert, LINER, and star-forming regions. The nucleus and ionization cones are dominated by Seyfert-type emission, which can be interpreted as predominantly photoionization by the active galactic nucleus (A…
We present the results of our ALMA HCN J=3-2 and HCO+ J=3-2 line observations of a uniformly selected sample (>25) of nearby ultraluminous infrared galaxies (ULIRGs) at z < 0.15. The emission of these dense molecular gas tracers and continuum are spatially resolved in the majority of observed ULIRGs for the first time with achieved synthesized beam sizes of ~0.2 arcsec or ~500 pc. In most ULIRGs, the HCN-to-HCO+ J=3-2 flux ratios in the nuclear regions within the beam size are systematically higher than those in the spatially extended regions. The elevated nuclear HCN J=3-2 emission could be r…
Spatially resolved near-IR and X-ray imaging of the central region of the Luminous Infrared Galaxy NGC 5135 is presented. The kinematical signatures of strong outflows are detected in the [FeII]1.64 μm emission line in a compact region at 0.9 kpc from the nucleus. The derived mechanical energy release is consistent with a supernova rate of 0.05-0.1 yr$^{-1}$. The apex of the outflowing gas spatially coincides with the strongest [FeII] emission peak and with the dominant component of the extranuclear hard X-ray emission. All these features provide evidence for a plausible direct physical link b…
We analyse the spatially resolved relation between stellar mass (M$_{\star}$) and star formation rate (SFR) in disk galaxies (i.e. the Main Sequence, MS). The studied sample includes eight nearby face-on grand-design spirals, e.g. the descendant of high-redshift, rotationally-supported star-forming galaxies. We exploit photometric information over 23 bands, from the UV to the far-IR, from the publicly available DustPedia database to build spatially resolved maps of stellar mass and star formation rates on sub-galactic scales of 0.5-1.5 kpc, by performing a spectral energy distribution fitting …
Emission from metal resonant lines has recently emerged as a potentially powerful probe of the structure of galactic winds at low and high redshift. In this work, we present only the second example of spatially resolved observations of NaI D emission from a galactic wind in a nearby galaxy (and the first 3D observations at any redshift). F05189-2524, a nearby (z=0.043) ultra luminous infrared galaxy powered by a quasar, was observed with the integral field unit on the Gemini Multi-Object Spectrograph (GMOS) at Gemini North. NaI D absorption in the system traces dusty filaments on the near side…
We present spatially resolved mass outflow rate measurements ($\dot M_{out}$) for the narrow line region of Markarian 34, the nearest Compton-thick type 2 quasar (QSO2). Spectra obtained with the Hubble Space Telescope and at Apache Point Observatory reveal complex kinematics, with distinct signatures of outflow and rotation within 2 kpc of the nucleus. Using multi-component photoionization models, we find that the outflow contains a total ionized gas mass of $M \approx 1.6 \times 10^6 M_{\odot}$. Combining this with the kinematics yields a peak outflow rate of $\dot M_{out} \approx 2.0 \pm 0.…
Post-starburst galaxies are crucial to disentangling the effect of star formation and quenching on galaxy demographics. They comprise, however, a heterogeneous population of objects, described in numerous ways. To obtain a well-defined and uncontaminated sample, we take advantage of spatially resolved spectroscopy to construct an unambiguous sample of E + A galaxies - post-starburst systems with no observed ongoing star formation. Using data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) Survey, in the fourth generation of the Sloan Digital Sky Survey (SDSS-IV), we have i…
We study spatially resolved properties (on spatial scales of $\sim 1-2$ kpc out to at least $3$ effective radii) of the stars, dust, and gas in ten nearby spiral galaxies. The properties of the stellar population and dust are derived by fitting the spatially resolved spectral energy distribution (SED) with more than 20 photometric bands ranging from far-ultraviolet to far-infrared. Our newly developed software piXedfit performs point spread function matching of images, pixel binning, and models the stellar light, dust attenuation, dust emission, and emission from a dusty torus heated by an act…
We have observed three luminous infrared galaxy systems (LIRGS) which are pairs of interacting galaxies, with the Galaxy H$α$ Fabry-Perot system (GH$α$FaS) mounted on the 4.2m William Herschel Telescope at the Roque de los Muchachos Observatory, and combined the observations with the Atacama Large Millimeter Array (ALMA) observations of these systems in CO emission to compare the physical properties of the star formation regions and the molecular gas clouds, and specifically the internal kinematics of the star forming regions. We identified 88 star forming regions in the H$α$ emission data-cub…
A correlation between the 24 μm continuum and the [NII] 205 μm line emission may arise if both quantities trace the star formation activity on spatially-resolved scales within a galaxy, yet has so far only been observed in the nearby edge-on spiral galaxy NGC 891. We therefore assess whether the [NII] 205 - 24 μm emission correlation has some physical origin or is merely an artefact of line-of-sight projection effects in an edge-on disc. We search for the presence of a correlation in Herschel and Spitzer observations of two nearby face-on galaxies, M51 and M83, and the interacting Antennae gal…
The formation of nuclear star clusters (NSCs) remains an open question. In this work, we use spatially resolved HST/STIS spectroscopic observations of three nearby NSCs (hosted by NGC 5102, NGC 5206, and NGC 205) to constrain their formation histories by exploring radial variations of the stellar populations within each cluster. Utilizing full-spectrum fitting, we find substantial age and metallicity gradients within the central 0."9 (16~pc) of the NSC in NGC 5102 where populations near the center are young/metal-rich (age ~400~Myr and [M/H] ~-0.4) and become older/metal-poor at larger radii (…
We present mosaicked long-slit spectral maps of 18 nearby Active Galactic Nuclei (AGNs), 2 LINERs, and 4 star-forming galaxies. With the resulting data cubes taken using the Kast dual spectrograph on the 3 m Shane telescope of the Lick Observatory, we measure the aperture effects on the spectroscopic classification of AGNs. With more starlight included in a larger aperture, the nuclear spectrum that is Seyfert-like may become contaminated. We generated standard spectroscopic classification diagrams in different observing apertures. These show quantitatively how the ensemble of Seyferts migrate…
