## Introduction to the HQ and MQ samples

Including:
1. A catalog of 7,681 cool stars which simultaneously have the HQ measurements of the DIBs λ5780, λ5797 and λ6614.

2. Three catalogs of the HQ samples of the DIBs λ5780, λ5797 and λ6614. The number of measurements of three DIBs are listed as follows:
   - 5780: 176,831
   - 5797: 13,473
   - 6614: 110,152

3. Three catalogs of the MQ samples of the DIBs λ5780, λ5797 and λ6614. The number of measurements of three DIBs are listed as follows:
   - 5780: 27,598
   - 5797: 42,735
   - 6614: 21,635

## Note on using the catalogs

- The infomation and units of each column are listed in the header of each FITS catalog.

- The central wavelength of the DIBs (e.g., `mu_5780`) by MCMC is **NOT** the real one because the fitting is carried out for the ISM residual spectra in the stellar rest frame. In other words, we have to add the radial velocity (RV) of the corresponding star to the central wavelength to get the real one. The RV is listed in the column `rv` of the catalog. Here we provide a Python code demo to transform the central wavelength to the real one:

```python
import os
import numpy as np
from astropy.table import Table


def get_real_mu(mu, rv):
    c = 299792.458  # speed of light in km/s
    doppler_factor = np.sqrt((1 + rv / c) / (1 - rv / c))
    return mu * doppler_factor


df = Table.read(path + 'HQ_DIB5780.fits').to_pandas()
rv = df['rv'].values  # read the RV of the stars
mu = df['mu_5780'].values  # read the central wavelength of the DIBs 5780
real_mu = get_real_mu(mu, rv)  # get the real central wavelength of the DIBs 5780
```