The python package to deal with infrared LDR and Teff.

# ir_ldr

The package `ir_ldr` is for measuring the spectral line depth of the APOGEE and WINERED spectra, calculating the line depth ratio (LDR) and finally deriving the effective temperature (T_LDR).

The LDR-Teff relations inside this package are from Jian+19, Taniguchi+18 and Jian+20a (in prep.). Please also refer to Fukue+15.

This package relys on `numpy`, `pandas`, `matplotlib` and `scipy`; it is based on python 3.

# Installation

`pip install ir_ldr`

# Tutorial

The synthetic spectra of a dwarf star (Teff=5000 K, logg=4.5 dex and feh=0 dex; generated from MOOG) in `ir_ldr/file/dwarf` for an example of T_LDR calculation.

```# Load the linelist.

# Here we use all the orders of synthetic spectra.
for order in [43, 44, 45, 46, 47, 48, 52, 53, 54, 55, 56, 57]:
sep=' +', skiprows=2, engine='python', names=['wav', 'residual'])
wav = spec['wav'].values
residual = spec['residual'].values

# Select the line pairs for a specific order
linelist_sub = linelist[linelist['order'] == order]
if len(linelist_sub) == 0:
continue
linelist_sub.reset_index(drop=True, inplace=True)

# Measure the line depth of low(1)- and high(2)-EP line.
# Here the signal to noise ratio for the target star and telluric standard are
# manually set as 300, but the S_N of synthetic spectra is much higher than that.
d1 = ir_ldr.depth_measure(wav, residual, linelist_sub['linewav1'], suffix=1, S_N=[300, 300])
d2 = ir_ldr.depth_measure(wav, residual, linelist_sub['linewav2'], suffix=2, S_N=[300, 300])

# Calculate the logLDR value.
lgLDR = ir_ldr.cal_ldr(d1, d2, type='lgLDR')
# Combine the Dataframes of one order.
record = ir_ldr.combine_df([linelist_sub, d1, d2, lgLDR])

if order == 43:
record_all = record
else:
record_all = pd.concat([record_all, record], sort=False)

# Calculate T_LDR
LDR = ir_ldr.ldr2tldr_winered_solar(record_all, df_output=True)
```

And the result `(T_LDR, T_LDR_err)` is:

```LDR[0:2]
>>> (5009.857201559249, 22.35966233607925)
# Note the T_LDR_err is not an accurate estimation here since the S_N is manually set.
```

# Author

Mingjie Jian (ssaajianmingjie@gmail.com)

PhD student, Department of Astronomy, the University of Tokyo

## Project details

This version 0.1.4

Uploaded `py3`