We present observations of 17 luminous (...)>8.7) local (z < 0.11) type II AGN. Our aim is to investigate the prevalence and nature of AGN-driven outflows in these galaxies by combining kinematic and ...ionization diagnostic information. We use non-parametric methods (e.g. W80, the width containing 80 per cent of the line flux) to assess the line widths in the central regions of our targets. The maximum values of W80 in each galaxy are in the range 400-1600 km s..., with a mean of 790 ± 90 km s... Such high velocities are strongly suggestive that these AGN are driving ionized outflows. Multi-Gaussian fitting is used to decompose the velocity structure in our galaxies. 14/17 of our targets require three separate kinematic components in the ionized gas in their central regions. The broadest components of these fits have FWHM = 530-2520 km s..., with a mean value of 920 ± 50 km s... By simultaneously fitting both the Hβ/O iii and Hα/N ii complexes, we construct ionization diagnostic diagrams for each component. 13/17 of our galaxies show a significant (>95 per cent) correlation between the N ii/H... ratio and the velocity dispersion of the gas. Such a correlation is the natural consequence of a contribution to the ionization from shock excitation and we argue that this demonstrates that the outflows from these AGN are directly impacting the surrounding ISM within the galaxies. (ProQuest: ... denotes formulae/symbols omitted.)
ABSTRACT
Galaxy mergers are crucial to understanding galaxy evolution, therefore we must determine their observational signatures to select them from large IFU galaxy samples such as MUSE and SAMI. ...We employ 24 high-resolution idealized hydrodynamical galaxy merger simulations based on the ‘Feedback In Realistic Environment’ (FIRE-2) model to determine the observability of mergers to various configurations and stages using synthetic images and velocity maps. Our mergers cover a range of orbital configurations at fixed 1:2.5 stellar mass ratio for two gas rich spirals at low redshift. Morphological and kinematic asymmetries are computed for synthetic images and velocity maps spanning each interaction. We divide the interaction sequence into three: (1) the pair phase; (2) the merging phase; and (3) the post-coalescence phase. We correctly identify mergers between first pericentre passage and 500 Myr after coalescence using kinematic asymmetry with 66 per cent completeness, depending upon merger phase and the field of view of the observation. We detect fewer mergers in the pair phase (40 per cent) and many more in the merging and post-coalescence phases (97 per cent). We find that merger detectability decreases with field of view, except in retrograde mergers, where centrally concentrated asymmetric kinematic features enhances their detectability. Using a cut-off derived from a combination of photometric and kinematic asymmetry, we increase these detections to 89 per cent overall, 79 per cent in pairs, and close to 100 per cent in the merging and post-coalescent phases. By using this combined asymmetry cut-off we mitigate some of the effects caused by smaller fields of view subtended by massively multiplexed integral field spectroscopy programmes.
We calibrate commonly used star formation rate (SFR) prescriptions using observations in five kiloparsec-sized fields in the nearby galaxy Andromeda (M31) at 10 pc spatial resolution. Our ...observations at different scales enable us to resolve the star-forming regions and to distinguish them from non-star-forming components. We use extinction-corrected H from optical integral field spectroscopy as our reference tracer and have verified its reliability via tests. It is used to calibrate monochromatic and hybrid (H +a×IR and far-UV+b×IR) SFR prescriptions, which use far-UV (GALEX), 22 m (Wide-field Infrared Survey Explorer), and 24 m (MIPS). Additionally, we evaluate other multiwavelength infrared tracers. Our results indicate that the SFR prescriptions do not change (in M31) with spatial scales or with subtraction of the diffuse component. For the calibration factors in the hybrid SFR prescriptions, we find a 0.2 and b 22 in M31, which are a factor of 5 higher than in the literature. As the fields in M31 exhibit high attenuation and low dust temperatures, lie at large galactocentric distances, and suffer from high galactic inclination compared to measurements in other galaxies, we propose that the fields probe a dust layer extended along the line of sight that is not directly spatially associated with star-forming regions. This (vertically) extended dust component increases the attenuation and alters the SFR prescriptions in M31 compared to literature measurements. We recommend that SFR prescriptions should be applied with caution at large galactocentric distances and in highly inclined galaxies, due to variations in the relative (vertical) distribution of dust and gas.
We report one of the first extragalactic observations of electron temperature variations across a spiral arm. Using Multi Unit Spectroscopic Explorer mosaic observations of the nearby galaxy NGC ...1672, we measure the N iiλ5755 auroral line in a sample of 80 H ii regions in the eastern spiral arm of NGC 1672. We discover systematic temperature variations as a function of distance perpendicular to the spiral arm. The electron temperature is lowest on the spiral arm itself and highest on the downstream side. Photoionization models of different metallicity, pressure, and age of the ionizing source are explored to understand what properties of the interstellar medium drive the observed temperature variations. An azimuthally varying metallicity appears to be the most likely cause of the temperature variations. The electron temperature measurements solidify recent discoveries of azimuthal variations of oxygen abundance based on strong lines, and rule out the possibility that the abundance variations are artifacts of the strong-line calibrations.
The PHANGS-MUSE survey Emsellem, Eric; Schinnerer, Eva; Santoro, Francesco ...
Astronomy and astrophysics (Berlin),
03/2022, Letnik:
659
Journal Article
Recenzirano
Odprti dostop
We present the PHANGS-MUSE survey, a programme that uses the MUSE integral field spectrograph at the ESO VLT to map 19 massive (9.4 < log(M⋆/M⊙)< 11.0) nearby (D ≲ 20 Mpc) star-forming disc ...galaxies. The survey consists of 168 MUSE pointings (1′ by 1′ each) and a total of nearly 15 × 106 spectra, covering ∼1.5 × 106 independent spectra. PHANGS-MUSE provides the first integral field spectrograph view of star formation across different local environments (including galaxy centres, bars, and spiral arms) in external galaxies at a median resolution of 50 pc, better than the mean inter-cloud distance in the ionised interstellar medium. This ‘cloud-scale’ resolution allows detailed demographics and characterisations of H II regions and other ionised nebulae. PHANGS-MUSE further delivers a unique view on the associated gas and stellar kinematics and provides constraints on the star-formation history. The PHANGS-MUSE survey is complemented by dedicated ALMA CO(2–1) and multi-band HST observations, therefore allowing us to probe the key stages of the star-formation process from molecular clouds to H II regions and star clusters. This paper describes the scientific motivation, sample selection, observational strategy, data reduction, and analysis process of the PHANGS-MUSE survey. We present our bespoke automated data-reduction framework, which is built on the reduction recipes provided by ESO but additionally allows for mosaicking and homogenisation of the point spread function. We further present a detailed quality assessment and a brief illustration of the potential scientific applications of the large set of PHANGS-MUSE data products generated by our data analysis framework. The data cubes and analysis data products described in this paper represent the basis for the first PHANGS-MUSE public data release and are available in the ESO archive and via the Canadian Astronomy Data Centre.
People with Cystic Fibrosis (CF) develop pulmonary inflammation, chronic infection and structural lung damage early in life, with these manifestations being prevalent among preschool children and ...infants. While early immune events are believed to play critical roles in shaping the progression, severity and disease burden later in life, T cells and their subsets are poorly studied in the CF lung, particularly during the formative early stages of disease.
Using flow cytometry, we analyzed Mucosal Associated Invariant T (MAIT) cells, γδ T cells, and Natural Killer T (NKT)-like cells in bronchoalveolar lavage (BAL) samples from seventeen children with CF, aged two to six years old. The effect of age, sex and lung infections on the frequencies of these cells in BAL samples was analysed (grouped data were tested for normality and compared by
-test or Kruskal-Wallis analysis).
No difference was noted in the proportions of unconventional T cells related to the sex or age of the children. The frequency of γδ T cells and MAIT cells appeared unchanged by infection status. However, viral infections were associated with a significant increase in the proportion of NKT-like cells.
By evaluating T cells in the lungs of children during the early formative stages of CF, this study identified potentially important interactions between these cells and viral pathogens.
Abstract
We present PHANGS–ALMA, the first survey to map CO
J
= 2 → 1 line emission at ∼1″ ∼100 pc spatial resolution from a representative sample of 90 nearby (
d
≲ 20 Mpc) galaxies that lie on or ...near the
z
= 0 “main sequence” of star-forming galaxies. CO line emission traces the bulk distribution of molecular gas, which is the cold, star-forming phase of the interstellar medium. At the resolution achieved by PHANGS–ALMA, each beam reaches the size of a typical individual giant molecular cloud, so that these data can be used to measure the demographics, life cycle, and physical state of molecular clouds across the population of galaxies where the majority of stars form at
z
= 0. This paper describes the scientific motivation and background for the survey, sample selection, global properties of the targets, Atacama Large Millimeter/submillimeter Array (ALMA) observations, and characteristics of the delivered data and derived data products. As the ALMA sample serves as the parent sample for parallel surveys with MUSE on the Very Large Telescope, the Hubble Space Telescope, AstroSat, the Very Large Array, and other facilities, we include a detailed discussion of the sample selection. We detail the estimation of galaxy mass, size, star formation rate, CO luminosity, and other properties, compare estimates using different systems and provide best-estimate integrated measurements for each target. We also report the design and execution of the ALMA observations, which combine a Cycle 5 Large Program, a series of smaller programs, and archival observations. Finally, we present the first 1″ resolution atlas of CO emission from nearby galaxies and describe the properties and contents of the first PHANGS–ALMA public data release.
The PHANGS-MUSE survey Emsellem, Eric; Schinnerer, Eva; Santoro, Francesco ...
Astronomy and astrophysics (Berlin),
03/2022, Letnik:
659
Journal Article
Recenzirano
Odprti dostop
We present the PHANGS-MUSE survey, a programme that uses the MUSE integral field spectrograph at the ESO VLT to map 19 massive (9.4 < log(
M
⋆
/
M
⊙
)< 11.0) nearby (
D
≲ 20 Mpc) star-forming disc ...galaxies. The survey consists of 168 MUSE pointings (1′ by 1′ each) and a total of nearly 15 × 10
6
spectra, covering ∼1.5 × 10
6
independent spectra. PHANGS-MUSE provides the first integral field spectrograph view of star formation across different local environments (including galaxy centres, bars, and spiral arms) in external galaxies at a median resolution of 50 pc, better than the mean inter-cloud distance in the ionised interstellar medium. This ‘cloud-scale’ resolution allows detailed demographics and characterisations of H
II
regions and other ionised nebulae. PHANGS-MUSE further delivers a unique view on the associated gas and stellar kinematics and provides constraints on the star-formation history. The PHANGS-MUSE survey is complemented by dedicated ALMA CO(2–1) and multi-band HST observations, therefore allowing us to probe the key stages of the star-formation process from molecular clouds to H
II
regions and star clusters. This paper describes the scientific motivation, sample selection, observational strategy, data reduction, and analysis process of the PHANGS-MUSE survey. We present our bespoke automated data-reduction framework, which is built on the reduction recipes provided by ESO but additionally allows for mosaicking and homogenisation of the point spread function. We further present a detailed quality assessment and a brief illustration of the potential scientific applications of the large set of PHANGS-MUSE data products generated by our data analysis framework. The data cubes and analysis data products described in this paper represent the basis for the first PHANGS-MUSE public data release and are available in the ESO archive and via the Canadian Astronomy Data Centre.
PHANGS–ALMA Data Processing and Pipeline Leroy, Adam K.; Hughes, Annie; Liu, Daizhong ...
The Astrophysical journal. Supplement series,
07/2021, Letnik:
255, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
We describe the processing of the PHANGS–ALMA survey and present the PHANGS–ALMA pipeline, a public software package that processes calibrated interferometric and total power data into ...science-ready data products. PHANGS–ALMA is a large, high-resolution survey of CO(2–1) emission from nearby galaxies. The observations combine ALMA’s main 12 m array, the 7 m array, and total power observations, and use mosaics of dozens to hundreds of individual pointings. We describe the processing of the
u
−
v
data, imaging and deconvolution, linear mosaicking, combining interferometer and total power data, noise estimation, masking, data product creation, and quality assurance. Our pipeline has a general design and can also be applied to Very Large Array and ALMA observations of other spectral lines and continuum emission. We highlight our recipe for deconvolution of complex spectral line observations, which combines multiscale clean, single-scale clean, and automatic mask generation in a way that appears robust and effective. We also emphasize our two-track approach to masking and data product creation. We construct one set of “broadly masked” data products, which have high completeness but significant contamination by noise, and another set of “strictly masked” data products, which have high confidence but exclude faint, low signal-to-noise emission. Our quality assurance tests, supported by simulations, demonstrate that 12 m+7 m deconvolved data recover a total flux that is significantly closer to the total power flux than the 7 m deconvolved data alone. In the appendices, we measure the stability of the ALMA total power calibration in PHANGS–ALMA and test the performance of popular short-spacing correction algorithms.
ABSTRACT
The processes of star formation and feedback, regulating the cycle of matter between gas and stars on the scales of giant molecular clouds (GMCs; ∼100 pc), play a major role in governing ...galaxy evolution. Measuring the time-scales of GMC evolution is important to identify and characterize the specific physical mechanisms that drive this transition. By applying a robust statistical method to high-resolution CO and narrow-band H α imaging from the PHANGS survey, we systematically measure the evolutionary timeline from molecular clouds to exposed young stellar regions on GMC scales, across the discs of an unprecedented sample of 54 star-forming main-sequence galaxies (excluding their unresolved centres). We find that clouds live for about 1−3 GMC turbulence crossing times (5−30 Myr) and are efficiently dispersed by stellar feedback within 1−5 Myr once the star-forming region becomes partially exposed, resulting in integrated star formation efficiencies of 1−8 per cent. These ranges reflect physical galaxy-to-galaxy variation. In order to evaluate whether galactic environment influences GMC evolution, we correlate our measurements with average properties of the GMCs and their local galactic environment. We find several strong correlations that can be physically understood, revealing a quantitative link between galactic-scale environmental properties and the small-scale GMC evolution. Notably, the measured CO-visible cloud lifetimes become shorter with decreasing galaxy mass, mostly due to the increasing presence of CO-dark molecular gas in such environment. Our results represent a first step towards a comprehensive picture of cloud assembly and dispersal, which requires further extension and refinement with tracers of the atomic gas, dust, and deeply embedded stars.
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