27 research outputs found
Introducing STRAUSS: A flexible sonification Python package
We introduce STRAUSS (Sonification Tools and Resources for Analysis Using
Sound Synthesis) a modular, self-contained and flexible Python sonification
package, operating in a free and open source (FOSS) capacity. STRAUSS is
intended to be a flexible tool suitable for both scientific data exploration
and analysis as well as for producing sonifications that are suitable for
public outreach and artistic contexts. We explain the motivations behind
STRAUSS, and how these lead to our design choices. We also describe the basic
code structure and concepts. We then present output sonification examples,
specifically: (1) multiple representations of univariate data (i.e., single
data series) for data exploration; (2) how multi-variate data can be mapped
onto sound to help interpret how those data variables are related and; (3) a
full spatial audio example for immersive Virtual Reality. We summarise,
alluding to some of the future functionality as STRAUSS development
accelerates.Comment: 6 pages, 4 figures, 28th International Conference on Auditory
Display, see here for linked resources:
https://data.ncl.ac.uk/articles/media/Trayford_2023_STRAUSS_ICAD_examples/2224118
Massive Low Surface Brightness Galaxies in the EAGLE Simulation
We investigate the formation and properties of low surface brightness
galaxies (LSBGs) with in the EAGLE
hydrodynamical cosmological simulation. Galaxy surface brightness depends on a
combination of stellar mass surface density and mass-to-light ratio (),
such that low surface brightness is strongly correlated with both galaxy
angular momentum (low surface density) and low specific star formation rate
(high ). This drives most of the other observed correlations between
surface brightness and galaxy properties, such as the fact that most LSBGs have
low metallicity. We find that LSBGs are more isolated than high surface
brightness galaxies (HSBGs), in agreement with observations, but that this
trend is driven entirely by the fact that LSBGs are unlikely to be close-in
satellites. The majority of LSBGs are consistent with a formation scenario in
which the galaxies with the highest angular momentum are those that formed most
of their stars recently from a gas reservoir co-rotating with a high-spin dark
matter halo. However, the most extended LSBG disks in EAGLE, which are
comparable in size to observed giant LSBGs, are built up via mergers. These
galaxies are found to inhabit dark matter halos with a higher spin in their
inner regions (), even when excluding the effects of baryonic
physics by considering matching halos from a dark matter only simulation with
identical initial conditions.Comment: Version accepted to MNRAS. 20 pages, 13 figures, plus appendix with 2
figure
Fade to grey: systematic variation of the galaxy attenuation curves with galaxy properties in EAGLE
We present a simple model for galaxy attenuation by distilling SKIRT
radiative transfer calculations for ~100,000 EAGLE galaxies at redshifts z=2-0.
Our model adapts the two component screen model of Charlot & Fall (2000),
parametrising the optical depth and slope of the ISM screen using the average
dust surface density, . We recover relatively tight
relations between these parameters for the EAGLE sample, but also provide the
scatter in these parameter owing to the morphological variation and orientation
of galaxies. We also find that these relations are nearly independent of
redshift in the EAGLE model. By pairing our model with an empirical
prescription for birth clouds below the resolution scale of the simulation, we
reproduce the observed relation between attenuation slope and optical depth for
the first time in a cosmological simulation. We demonstrate that this result is
remarkably independent of the attenuation properties assumed for birth cloud
screen, merely requiring a boosted attenuation for infant stars. We present
this model with a view to interpreting observations, as well as processing
semi-analytic models and other hydrodynamic simulations.Comment: 16 pages (incl. 4 appendix pages), 8 Figures. Submitted to MNRAS.
Comments welcome
Inspecting spectra with sound: proof-of-concept & extension to datacubes
We present a novel approach to inspecting galaxy spectra using sound, via
their direct audio representation ('spectral audification'). We discuss the
potential of this as a complement to (or stand-in for) visual approaches. We
surveyed 58 respondents who use the audio representation alone to rate 30
optical galaxy spectra with strong emission lines. Across three tests, each
focusing on different quantities measured from the spectra (signal-to-noise
ratio, emission-line width, & flux ratios), we find that user ratings are well
correlated with measured quantities. This demonstrates that physical
information can be independently gleaned from listening to spectral
audifications. We note the importance of context when rating these
sonifications, where the order examples are heard can influence responses.
Finally, we adapt the method used in this promising pilot study to spectral
datacubes. We suggest that audification allows efficient exploration of
complex, spatially-resolved spectral data.Comment: 6 pages, 3 figures, accepted for publication in RASTI. Supplementary
data (including animated figure) available at
https://doi.org/10.25405/data.ncl.2281644
Small-scale galaxy clustering in the eagle simulation
We study present-day galaxy clustering in the EAGLE cosmological hydrodynamical simulation. EAGLE’s galaxy formation parameters were calibrated to reproduce the redshift z = 0.1 galaxy stellar mass function, and the simulation also reproduces galaxy colours well. The simulation volume is too small to correctly sample large-scale fluctuations and we therefore concentrate on scales smaller than a few mega parsecs. We find very good agreement with observed clustering measurements from the Galaxy And Mass Assembly (GAMA) survey, when galaxies are binned by stellar mass, colour or luminosity. However, low-mass red galaxies are clustered too strongly, which is at least partly due to limited numerical resolution. Apart from this limitation, we conclude that EAGLE galaxies inhabit similar dark matter haloes as observed GAMA galaxies, and that the radial distribution of satellite galaxies, as a function of stellar mass and colour, is similar to that observed as well
It's not easy being green: The evolution of galaxy colour in the EAGLE simulation
We examine the evolution of intrinsic u-r colours of galaxies in the EAGLE cosmological hydrodynamical simulations, which has been shown to reproduce the observed redshift z=0.1 colour-magnitude distribution well. The median u-r of star-forming ('blue cloud') galaxies reddens by 1 mag from z=2 to 0 at fixed stellar mass, as their specific star formation rates decrease with time. A red sequence starts to build-up around z=1, due to the quenching of low-mass satellite galaxies at the faint end, and due to the quenching of more massive central galaxies by their active galactic nuclei (AGN) at the bright end. This leaves a dearth of intermediate-mass red sequence galaxies at z=1, which is mostly filled in by z=0. We quantify the time-scales of colour transition due to satellite and AGN quenching, finding that most galaxies spend less than 2 Gyr in the 'green valley'. On examining the trajectories of galaxies in a colour-stellar mass diagram, we identify three characteristic tracks that galaxies follow (quiescently star-forming, quenching and rejuvenating galaxies) and quantify the fraction of galaxies that follow each track