{
  "name": "X-ray Source Classification Tree",
  "description": "A decision tree for classifying X-ray sources based on morphology, photon statistics, and spectral hardness.",
  "version": "1.0",
  "parameters": {
    "Confidence": "Source detection confidence from DBCSCAN & Bootstrap",
    "Photon_Count": "Total number of detected photons in the source",
    "Adaptive_Radius_pix": "Adaptive radius in pixels used for source extraction",
    "Hardness_Ratio": "Ratio of hard to soft band counts (HR)",
    "Concentration_C": "Concentration index (C), measures central compactness",
    "Radial_Excess": "Radial excess (RE), measures extended emission",
    "Center_X": "X-coordinate of source center",
    "Center_Y": "Y-coordinate of source center"
  },
  "decision_tree": [
    {
      "step": 1,
      "condition": "Confidence < 0.50",
      "description": "Low confidence source detection",
      "if_true": "Classification: Noise / 噪声",
      "if_false": "Go to step 2"
    },
    {
      "step": 2,
      "condition": "Confidence > 0.8 AND Photon_Count > 8?",
      "description": "Check if source has sufficient photons and is not too faint",
      "if_true": "Go to step 3",
      "if_false": "Classification: Point Candidate / 可能点源"
    },
    {
      "step": 3,
      "condition": "Concentration_C == 0",
      "description": "Check if initial C is 0 (Hollow)",
      "if_true": "Refine Center: 定位最近光子 → Compute C, HR, Excess → Go to step 4",
      "if_false": "Compute C, HR, Excess → Go to step 4"
    },
    {
      "step": 4,
      "condition": "Hardness_Ratio (HR) > -0.20",
      "description": "High HR indicates harder spectrum",
      "if_true": "Go to step 5",
      "if_false": "Go to step 6"
    },
    {
      "step": 5,
      "condition": "Radial_Excess > 0.05",
      "description": "Extended emission detected",
      "if_true": "Classification: AGN + Halo",
      "if_false": "Classification: AGN / Hard Point"
    },
    {
      "step": 6,
      "condition": "Radial_Excess > 0.02",
      "description": "Mild extension",
      "if_true": "Go to step 7",
      "if_false": "Classification: Star / Soft Point"
    },
    {
      "step": 7,
      "condition": "Concentration_C < 0.80",
      "description": "Check if core is weak or diffuse",
      "if_true": "Classification: GALAXY HALO",
      "if_false": "Classification: Ambiguous"
    }
  ],
  "classification_mapping": {
    "Noise / 噪声": "低置信度，可能为背景噪声",
    "Point Candidate / 可能点源": "光子数不足或未达阈值，需进一步验证",
    "AGN + Halo": "活动星系核伴晕，具有硬谱和扩展结构",
    "AGN / Hard Point": "硬谱点源，可能是类星体或黑洞候选体",
    "Star / Soft Point": "软谱点源，可能是恒星或白矮星",
    "GALAXY HALO": "星系晕，扩散结构但核心较弱",
    "Ambiguous": "无法明确分类，特征不典型"
  },
   "references": [
  {
    "id": "ref1",
    "citation": "Evans, I. N., et al. 2024, ApJS, 274, 22",
    "description": "Establishes the industry standard for X-ray source parameter extraction, specifically defining the canonical bands for Hardness Ratio calculations and the PSF-based methodology for quantifying source extent, serving as the methodological foundation for our data pipeline.Establishes the industry standard for X-ray source parameter extraction, specifically defining the canonical bands for Hardness Ratio calculations and the PSF-based methodology for quantifying source extent, serving as the methodological foundation for our data pipeline."
  } ,  
  {
    "id": "ref2",
    "citation": "Kovács, O. E., Werner, N., Bogdán, Á., & de Plaa, J. 2025, A&A, 704, A196",
    "description": "Validates the physical basis of identifying extended thermal halos via Radial Excess and Hardness Ratio, supported by the observed dominance of hard point sources in massive compact galaxies."
  } ]
}