J/A+A/639/A138 3D dust extinction map (Leike+, 2020)
Resolving nearby dust clouds.
Leike R.H., Glatzle M., Ensslin T.A.
<Astron. Astrophys. 639, A138 (2020)>
=2020A&A...639A.138L 2020A&A...639A.138L (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Extinction ; Interstellar medium ; Optical ; Infrared
Keywords: methods: data analysis - dust, extinction - ISM: structure -
local interstellar matter
Abstract:
Mapping the interstellar medium in 3D provides a wealth of insights
into its inner working. The Milky Way is the only galaxy,
for which a detailed 3D mapping can be achieved in principle. In this
paper, we reconstruct the dust density in and around the local
super-bubble.
The combined data from surveys such as Gaia, 2MASS, PANSTARRS, and
ALLWISE provide the necessary information to make detailed maps of the
interstellar medium in our surrounding. To this end, we use
variational inference and Gaussian processes to model the dust
extinction density, exploiting its intrinsic correlations.
We reconstruct a highly resolved dust map, showing the nearest dust
clouds at a distance of up to 400pc with a resolution of 1pc.
Our reconstruction provides insights into the structure of the
interstellar medium.We compute summary statistics of the spectral
index and the 1-point function of the logarithmic dust extinction
density, which may constrain simulations of the interstellar medium
that achieve similar resolution.
Description:
There are 4 files in the data set.
The file 'samples.h5' contains 12 contains approximate posterior
samples of the dust density, the other files contain summary
statistics thereof and can be computed from the file 'samples.h5', but
are a lot smaller.
Provided under the terms of the Creative Commons Attribution 4.0
International License (CC BY 4.0).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
samples.h5 512 27722256 Approximate posterior samples of the dust density
mean_std.h5 512 4620383 Sample mean and variance of the file
power.h5 512 1136254 The power spectra computed from samples.h5
histogram.h5 512 35 The histogram computed from samples.h5
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
Description of file:
samples.h5:
Attributes:
- information: contains information about the origin, content, and license
of this file as a string.
Contains:
- samples:
A (12,740,740,540) data array of float32
The data cube has four dimensions.
The ijkl-th data value contains the extinction per parsec in the region
where the x coordinate reaches from (j-370)pc to (j-369)pc , analogously
for (k,y).
The z-coordinate in the ijkl-th data value ranges from (l-270)pc to
(l-269)pc.
The galactic center lies in positive x direction, z is the coordinate
axis perpendicular to the galactic disk.
The index i counts through the posterior samples.
Note that the extinction is not in magnitudes but in natural logarithmic
units, i.e. a value of 1 corresponds to an intensity reduction of e^{-1}
for G-Band photons traveling one parsec through that dust.
Attributes:
- information: contains the above paragraph as a string.
mean_std.h5: Sample mean and variance of the file 'samples.h5'
Attributes:
- information: contains information about the origin, content, and license of
this file as a string.
Contains:
- mean:
A (740,740,540) array of float32
The data cube has three dimensions.
The jkl-th data value contains the extinction per parsec in the region
where the x coordinate reaches from (j-370)pc to (j-369)pc , analogously
for (k,y).
The z-coordinate in the jkl-th data value ranges from (l-270)pc to
(l-269)pc.
The galactic center lies in positive x direction, z is the coordinate axis
perpendicular to the galactic disk.
Note that the extinction is not in magnitudes but in natural logarithmic
units, i.e. a value of 1 corresponds to an intensity reduction of e^{-1}
for G-Band photons traveling one parsec through that dust.
Attributes:
- information: contains the above paragraph as a string.
- std:
A (740,740,540) array of float32
One sigma uncertainty estimates on the extinction values. Note that the
uncertainties of individual voxels are correlated, for a detailed analysis
using the posterior samples is recommended.
Attributes:
- information: contains the above paragraph as a string.
power.h5: The power spectra computed from samples.h5
Attributes:
- information: contains information about the origin, content, and license of
this file as a string.
Contains:
- power:
An array of shape (12, 11187652)
The ij-th data value contains the i-th sample of the j-th k-mode of the
Power spectrum of the logarithmic G-band dust extinction cross section
density.
The power spectra were computed by Pk= |F(s)|2/V where F is the Fourier
transform, s is the dust extinction density in the G-band in e-folds per
parsec, and V is the volume of the map, i.e. 7402*540pc3.
To obtain Pk, values with the same k were averaged.
The power is given in units of pc.
The dataset 'power_coordinates' contains the corresponding Fourier
coordinates to this dataset in units of pc-1
Attributes:
- information: contains the above paragraph as a string.
- power_coordinates:
An array of shape (11187652)
Coordinates for the power spectrum.
Note that we follow the Fourier-convention where the minimal non-zero
k-coordinate is 1/L (without 2 Pi), where L is the Length of the box
(740pc).
Coordinates are given in units of 1/pc.
Attributes:
- information: contains the above paragraph as a string.
histogram.h5: The histogram computed from samples.h5
Attributes:
- information: contains information about the origin, content, and license of
this file as a string
Contains:
- histogram:
An array of shape (12, 256)
The ij-th data value corresponds to the number of voxels in the i-th
posterior sample with dust extinction density in e-folds per parsec
between bin_edges[j] and bin_edges[j+1].
Attributes:
- information: contains the above paragraph as a string.
- bin_edges:
An array of shape (257)
Edges of the bins of the histogram. Units are in e-folds per parsec.")
Attributes:
- information: contains the above paragraph as a string.
Acknowledgements:
Reimar Leike, reimar(at)MPA-Garching.MPG.DE
(End) Patricia Vannier [CDS] 29-May-2020