Disentangling the Galactic Faraday sky

Sky maps of Hutschenreuter et al. (2023)

See https://arxiv.org/abs/2304.12350.

This data set contains the statistical results for 5 different sky models, namely: 

The integrated LoS component of the Galactic magnetic field, weighted by electron density 

The LoS-integrated electron density of the Milky Way, i.e. the Galactic dispersion measure 

The integrated squared electron density of the Milky Way, i.e. the Galactic emission measure

Conversion factor between squared DM and EM, can be interpreted as the length of the LoS in ideal conditions

Conversion factor between EM and DM, can be interpreted as the LoS-averaged electron density of the Milky Way in ideal conditions

The results for these models are provided by reporting sky maps of the posterior mean and the corresponding standard deviation.Note that the uncertainties of individual pixels and the different sky maps are correlated, for a detailed analysis using the posterior samples is recommended.These are provided for the integrated LoS component of the Galactic magnetic field, the logartihmic DM and the logarithmic L_DM2EM. From those, the uncertainties of all other sky maps can be estimated using the equations in the paper.

Mean and uncertainties are also provided in fits file format, for convenience.

All results are provided under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0). 

The hdf5 files are organised as follows:

<name>_mean_std.hdf5 

  Attributes:   - reference: https://arxiv.org/abs/2304.12350   - license: Provided under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0).    - description: Sampled posterior mean and variance of the <model description>    - name: <name>   - unit: <physical unit of the sky maps> 

  Contains:    - mean:      Contains the posterior mean as a one-dimensional array of float64 with 786432 entries.       This conforms to a HealPix map with nside parameter 256 and in RING ordering.

      Attributes:        - information: contains the above paragraph as a string.        - unit: <physical unit of the sky maps>         - size: 786432        - nside: 256        - ordering: RING        - dtype: float64        - coordinate system: G        - std:      Contains the posterior one sigma uncertainty estimates of the <name> sky model as a one-dimensional array of float64 with 786432 entries.       This conforms to a HealPix map with nside parameter 256 and in RING ordering.      Note that the uncertainties of individual pixels are correlated, for a detailed analysis using the posterior samples is recommended, which are provided.)            Attributes:        - information: contains the above paragraph as a string.        - unit: <physical unit of the sky maps>         - size: 786432        - nside: 256        - ordering: RING        - dtype: float64        - coordinate system: G    

<name>_sample.hdf5

  Attributes:   - reference: https://arxiv.org/abs/2304.12350   - license: Provided under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0).    - description: Sampled posterior mean and variance of the <model description>    - name: <name>   - unit: <physical unit of the sky maps>    - coordinate

  Contains for each sample i :         - sample_i:      Contains sample i as a one-dimensional array of float64 with 786432 entries.       This conforms to a HealPix map with nside parameter 256 and in RING ordering.

      Attributes:        - information: contains the above paragraph as a string.        - unit: <physical unit of the sky maps>         - size: 786432        - nside: 256        - ordering: RING        - dtype: float64        - coordinate system: G

Hutschenreuter等人(2023)的天图数据集

详见论文链接 https://arxiv.org/abs/2304.12350。

本数据集包含5种不同天区模型的统计结果，具体如下：
1. 以电子密度加权的银河系磁场沿视线方向（Line of Sight, LoS）的积分分量
2. 银河系视线方向积分电子密度，即银河色散量（Dispersion Measure, DM）
3. 银河系电子密度平方的积分值，即银河发射量（Emission Measure, EM）
4. 色散量平方与发射量之间的转换因子，可理解为理想条件下视线方向的长度
5. 发射量与色散量之间的转换因子，可理解为理想条件下银河系视线平均电子密度

上述模型的结果以天图的后验均值及其对应标准差的形式提供。请注意，单个像素的不确定度与不同天图之间存在相关性，建议使用后验样本开展详细分析。针对银河系磁场沿视线方向的积分分量、对数色散量以及对数L_DM2EM，我们已提供后验样本，其余所有天图的不确定度均可通过论文中的公式进行估算。

为方便使用，均值与不确定度也以FITS文件（Flexible Image Transport System, FITS）格式提供。

所有结果均采用知识共享署名4.0国际许可协议（Creative Commons Attribution 4.0 International License, CC BY 4.0）发布。

HDF5文件的组织形式如下：

<name>_mean_std.hdf5
属性：
- reference: https://arxiv.org/abs/2304.12350
- license: 本数据集采用知识共享署名4.0国际许可协议（CC BY 4.0）发布
- description: "<模型描述>"的后验均值与方差采样结果
- name: "<名称>"
- unit: "<天图的物理单位>"
包含内容：
- mean：以786432个float64类型一维数组形式存储的后验均值。该数据符合nside参数为256、采用RING排序的HealPix天图格式。
属性：
- information: 包含上述说明段落的字符串
- unit: "<天图的物理单位>"
- size: 786432
- nside: 256
- ordering: RING
- dtype: float64
- coordinate system: G
- std：以786432个float64类型一维数组形式存储的"<名称>"天区模型的后验1σ不确定度估计值。该数据符合nside参数为256、采用RING排序的HealPix天图格式。请注意，单个像素的不确定度存在相关性，建议使用提供的后验样本进行详细分析。
属性：
- information: 包含上述说明段落的字符串
- unit: "<天图的物理单位>"
- size: 786432
- nside: 256
- ordering: RING
- dtype: float64
- coordinate system: G

<name>_sample.hdf5
属性：
- reference: https://arxiv.org/abs/2304.12350
- license: 本数据集采用知识共享署名4.0国际许可协议（CC BY 4.0）发布
- description: "<模型描述>"的后验均值与方差采样结果
- name: "<名称>"
- unit: "<天图的物理单位>"
- coordinate system: G
包含内容：针对每个样本i：
- sample_i：以786432个float64类型一维数组形式存储的样本i。该数据符合nside参数为256、采用RING排序的HealPix天图格式。
属性：
- information: 包含上述说明段落的字符串
- unit: "<天图的物理单位>"
- size: 786432
- nside: 256
- ordering: RING
- dtype: float64
- coordinate system: G