ASTRA-DESI EDR Release v0.6

ASTRA-DESI Early Data Release (EDR) This record bundles the ASTRA-DESI early data products for the 20 DESI rosettes (zones 00–19). Every catalogue is delivered as a compressed FITS binary table (.fits.gz) whose first extension (HDU 1) contains the data. File headers store the keywords RELEASE=EDR and the corresponding ZONE label for quick checks. Tracer Number of objects BGS 241,746 LRG 112,649 ELG 267,345 QSO 35,566 Directory layout The archive preserves the NERSC production tree. Top-level folders contain: raw/ – merged real and random catalogues per zone. classification/ – neighbour count summaries per tracer and random iteration. probabilities/ – web-type membership probabilities derived from the classification counts. pairs/ – sparse list of target pairs used when counting neighbours. groups/ – FoF group catalogues for objects classified as filaments and voids. Naming conventions raw/zone_XX.fits.gz – zone index XX is zero-padded (00–19). classification/zone_XX_classified.fits.gz – combined tracer summary for the zone. probabilities/zone_XX_probability.fits.gz – per-object web-type probabilities. pairs/zone_XX_pairs.fits.gz – neighbour pairs for the zone. groups/zone_XX_groups_fof_filament.fits.gz – filament FoF groups restricted to data targets for all iterations per zone. groups/zone_XX_groups_fof_void.fits.gz – void FoF groups for all random iterations per zone. Column reference Raw catalogues (raw/*.fits.gz) Column Type Description TARGETID int64 DESI target identifier. RA float64 Right ascension in degrees. DEC float64 Declination in degrees. Z float64 Spectroscopic redshift. XCART, YCART, ZCART float64 Comoving Cartesian coordinates (Mpc) computed with the Planck18 cosmology. TRACERTYPE string Base tracer with suffix _DATA or _RAND (BGS_ANY, ELG, LRG, QSO). RANDITER int32 -1 for real objects, otherwise the random iteration index (0–99). Each raw file merges all tracers for its zone. Random catalogues mirror the data counts for every tracer and random iteration. Classification catalogues (classification/*.fits.gz) Column Type Description TARGETID int64 Identifier of the central object. RANDITER int32 -1 for data rows, otherwise the random catalogue index. ISDATA bool True for data rows; False for random iterations. NDATA int32 Number of neighbour pairs built from data tracers for this target. NRAND int32 Number of neighbour pairs contributed by random tracers. TRACERTYPE string Tracer family (BGS_ANY, ELG, LRG, QSO). Probability catalogues (probabilities/*.fits.gz) Column Type Description TARGETID int64 Identifier of the object. TRACERTYPE string Tracer family. PVOID float32 Probability of the object being a void class. PSHEET float32 Probability of the sheet class. PFILAMENT float32 Probability of the filament class. PKNOT float32 Probability of the knot class. Pair catalogues (pairs/*.fits.gz) Column Type Description TARGETID1 int64 Central object in the neighbour pair. TARGETID2 int64 Neighbour contributing to the count. RANDITER int32 -1 for data pairs, otherwise random catalogue index. Group catalogues (groups/*.fits.gz) Column Type Description TRACERTYPE string Tracer family. TARGETID int64 Member identifier. RANDITER int32 Random iteration index. WEBTYPE string Cosmic web class. GROUPID int32 FoF group label unique within each (zone, tracer). NPTS int32 Number of members in the group. XCM, YCM, ZCM float64 Group barycentre in comoving Cartesian coordinates (Mpc). A, B, C float64 Semi-axis lengths of the inertia ellipsoid (Mpc) ordered A≥B≥C. LINKLEN float64 FoF linking length. ISDATA bool True for data rows; False for random iterations. The group finder is executed separately for each tracer. The linking length is computed per tracer and iteration using the analytic comoving volume of the region. Using the catalogues All FITS tables are compressed with gzip. Random catalogues use RANDITER values 0–99; filtering on RANDITER >= 0 isolates the random iterations. The Cartesian coordinates assume the Planck18 cosmology provided by astropy.cosmology.Planck18.ASTRA-DESI 早期数据发布（Early Data Release, EDR） 本数据集整合了针对20个DESI巡天区域（区域00至19）的ASTRA-DESI早期数据产品。所有目录均以压缩的FITS二进制表格（.fits.gz）格式交付，其第一个扩展区（HDU 1）存储数据。文件头中存储有RELEASE=EDR关键字与对应区域标签，便于快速校验。 ### 示踪物 天体数量 BGS 241,746 LRG 112,649 ELG 267,345 QSO 35,566 ### 目录结构 本归档保留了NERSC的生产目录树结构，顶层文件夹包含： raw/ – 各区域的实测目录与随机模拟目录合并文件 classification/ – 每个示踪物与随机迭代的邻域计数汇总文件 probabilities/ – 基于分类计数得到的宇宙网类型归属概率文件 pairs/ – 邻域计数时使用的稀疏目标对列表文件 groups/ – 被分类为纤维结构与空洞结构天体的FoF群目录文件 ### 命名规范 raw/zone_XX.fits.gz – 区域索引XX为补零格式（00至19） classification/zone_XX_classified.fits.gz – 对应区域的合并示踪物汇总文件 probabilities/zone_XX_probability.fits.gz – 单天体宇宙网类型概率文件 pairs/zone_XX_pairs.fits.gz – 对应区域的邻域对文件 groups/zone_XX_groups_fof_filament.fits.gz – 各区域所有迭代中仅包含实测目标的纤维结构FoF群文件 groups/zone_XX_groups_fof_void.fits.gz – 各区域所有随机迭代的空洞结构FoF群文件 ### 列参考表 #### 原始目录（raw/*.fits.gz） | 列名 | 数据类型 | 描述 | |------|----------|------| | TARGETID | int64 | DESI目标标识符 | | RA | float64 | 以度为单位的赤经 | | DEC | float64 | 以度为单位的赤纬 | | Z | float64 | 光谱红移 | | XCART, YCART, ZCART | float64 | 基于Planck18宇宙学模型计算得到的共动直角坐标（单位：Mpc） | | TRACERTYPE | string | 基础示踪物，后缀为_DATA或_RAND（BGS_ANY、ELG、LRG、QSO） | | RANDITER | int32 | 实测天体取值为-1，否则为随机迭代索引（0至99） | 每个原始目录文件会合并对应区域的所有示踪物。随机目录与每个示踪物及随机迭代的数据计数保持一致。 #### 分类目录（classification/*.fits.gz） | 列名 | 数据类型 | 描述 | |------|----------|------| | TARGETID | int64 | 中心天体的标识符 | | RANDITER | int32 | 实测天体取值为-1，否则为随机目录索引 | | ISDATA | bool | 实测行取值为True，随机迭代取值为False | | NDATA | int32 | 该目标基于实测示踪物生成的邻域对数量 | | NRAND | int32 | 随机示踪物贡献的邻域对数量 | | TRACERTYPE | string | 示踪物类别（BGS_ANY、ELG、LRG、QSO） | #### 概率目录（probabilities/*.fits.gz） | 列名 | 数据类型 | 描述 | |------|----------|------| | TARGETID | int64 | 天体标识符 | | TRACERTYPE | string | 示踪物类别 | | PVOID | float32 | 天体属于空洞类别的概率 | | PSHEET | float32 | 天体属于片层类别的概率 | | PFILAMENT | float32 | 天体属于纤维结构类别的概率 | | PKNOT | float32 | 天体属于结点类别的概率 | #### 邻域对目录（pairs/*.fits.gz） | 列名 | 数据类型 | 描述 | |------|----------|------| | TARGETID1 | int64 | 邻域对中的中心天体 | | TARGETID2 | int64 | 参与计数的邻域天体 | | RANDITER | int32 | 实测对取值为-1，否则为随机目录索引 | #### 群目录（groups/*.fits.gz） | 列名 | 数据类型 | 描述 | |------|----------|------| | TRACERTYPE | string | 示踪物类别 | | TARGETID | int64 | 成员天体标识符 | | RANDITER | int32 | 随机迭代索引 | | WEBTYPE | string | 宇宙网类别 | | GROUPID | int32 | 每个（区域、示踪物）组合内唯一的FoF群标签 | | NPTS | int32 | 群内成员数量 | | XCM, YCM, ZCM | float64 | 群的共动直角坐标下的质心（单位：Mpc） | | A, B, C | float64 | 惯性椭球的半长轴长度（单位：Mpc），排序为A≥B≥C | | LINKLEN | float64 | FoF连接长度 | | ISDATA | bool | 实测行取值为True，随机迭代取值为False | FoF群查找器会针对每个示踪物独立运行。连接长度会基于区域的解析共动体积，按每个示踪物和迭代单独计算。 ### 目录使用说明 所有FITS表格均采用gzip压缩。 随机目录的RANDITER取值范围为0至99；通过筛选`RANDITER >= 0`可分离出随机迭代目录。 直角坐标基于`astropy.cosmology.Planck18`提供的Planck18宇宙学模型。