inv_RV_dependence.py

# This script calculates and fits the R(V) dependent relationship

import numpy as np
import pandas as pd

from matplotlib import pyplot as plt
from collections import Counter
from scipy import stats, interpolate
from astropy.modeling import models, fitting
from astropy.table import Table
from matplotlib.lines import Line2D
from synphot import SpectralElement, SourceSpectrum, Observation
from synphot.models import Empirical1D

import astropy.units as u

from measure_extinction.extdata import ExtData
from dust_extinction.parameter_averages import CCM89, F19


def get_data(inpath, starpair_list_diff, starpair_list_dense, norm="V"):
    """
    Obtain the required data for all stars in the star pair lists:
        - A(lambda)/A(V)
        - 1/R(V)
        - A(V)

    Parameters
    ----------
    inpath : string
        Path to the input data files

    starpair_list_diffuse : list of strings
        List of diffuse star pairs to include in the fitting, in the format "reddenedstarname_comparisonstarname" (no spaces)

    starpair_list_dense : list of strings
        List of dense star pairs to include in the fitting, in the format "reddenedstarname_comparisonstarname" (no spaces)

    norm : string [default="V"]
        Band or wavelength for the normalization

    Returns
    -------
    1/R(V) with uncertainties, A(V) with uncertainties, A(lambda)/A(V) with uncertainties, wavelengths, boolean for dense/diffuse
    """
    starpair_list = starpair_list_diff + starpair_list_dense
    inv_RVs = np.zeros((len(starpair_list), 3))
    AVs = np.zeros((len(starpair_list), 3))

    # determine the wavelengths at which to retrieve the extinction data
    extdata_model = ExtData("%s%s_ext.fits" % (inpath, starpair_list[0].lower()))
    waves = np.sort(
        np.concatenate(
            (
                extdata_model.waves["SpeX_SXD"].value,
                extdata_model.waves["SpeX_LXD"].value,
            )
        )
    )
    alavs = np.full((len(waves), len(starpair_list)), np.nan)
    alav_uncs = np.full((len(waves), len(starpair_list)), np.nan)
    dense_bool = np.full(len(starpair_list), False)

    # retrieve the information for all stars
    for i, starpair in enumerate(starpair_list):
        # retrieve 1/R(V) and A(V) (with uncertainties)
        extdata = ExtData("%s%s_ext.fits" % (inpath, starpair.lower()))
        inv_RVs[i] = np.array(extdata.columns["IRV"])
        AVs[i] = np.array(extdata.columns["AV"])

        # transform the curve from E(lambda-V) to A(lambda)/A(V)
        extdata.trans_elv_alav()

        # get the good data in flat arrays
        (flat_waves, flat_exts, flat_exts_unc) = extdata.get_fitdata(
            ["SpeX_SXD", "SpeX_LXD"]
        )

        # convert extinction from A(lambda)/A(V) to A(lambda)/A(norm) if norm is not "V"
        if norm != "V":
            ind1 = np.abs(flat_waves.value - norm).argmin()
            flat_exts = flat_exts / flat_exts[ind1]
            flat_exts_unc = flat_exts_unc / flat_exts[ind1]

        # retrieve A(lambda)/A(V) at all wavelengths
        for j, wave in enumerate(waves):
            if wave in flat_waves.value:
                alavs[j][i] = flat_exts[flat_waves.value == wave]
                alav_uncs[j][i] = flat_exts_unc[flat_waves.value == wave]

        # flag the dense sightlines
        if starpair in dense:
            dense_bool[i] = True

    return inv_RVs, AVs, alavs, alav_uncs, waves, dense_bool


def get_phot(waves, exts, bands):
    """
    Compute the extinction in the requested bands

    Parameters
    ----------
    waves : numpy.ndarray
        The wavelengths

    exts : numpy.ndarray
        The extinction values at wavelengths "waves"

    bands: list of strings
        Bands requested

    Outputs
    -------
    band extinctions : numpy array
        Calculated band extinctions
    """
    # create a SourceSpectrum object from the extinction curve
    spectrum = SourceSpectrum(
        Empirical1D,
        points=waves * 1e4,
        lookup_table=exts,
    )

    # path for band response curves
    band_path = (
        "/Users/mdecleir/measure_extinction/measure_extinction/data/Band_RespCurves/"
    )

    # dictionary linking the bands to their response curves
    bandnames = {
        "J": "2MASSJ",
        "H": "2MASSH",
        "K": "2MASSKs",
        "IRAC1": "IRAC1",
        "IRAC2": "IRAC2",
        "WISE1": "WISE1",
        "WISE2": "WISE2",
        "L": "AAOL",
        "M": "AAOM",
    }

    # compute the extinction value in each band
    band_ext = np.zeros(len(bands))
    for k, band in enumerate(bands):
        # create the bandpass (as a SpectralElement object)
        bp = SpectralElement.from_file(
            "%s%s.dat" % (band_path, bandnames[band])
        )  # assumes wavelengths are in Angstrom!!
        # integrate the extinction curve over the bandpass, only if the bandpass fully overlaps with the extinction curve (this actually excludes WISE2)
        if bp.check_overlap(spectrum) == "full":
            obs = Observation(spectrum, bp)
            band_ext[k] = obs.effstim().value
        else:
            band_ext[k] = np.nan
    return band_ext


def calc_corr(f, f_unc, g, g_unc, fac, fac_unc):
    """
    Function to calculate the correlation coefficients between two (arrays of) quantities (functions) f and g that have a common denominator fac with uncertainty fac_unc

    Parameters
    ----------
    f : np.ndarray
        Numpy array with values of the first quantity

    f_unc : np.ndarray
        Numpy array with uncertainties of the first quantity

    g : np.ndarray
        Numpy array with values of the second quantity

    g_unc : np.ndarray
        Numpy array with uncertainties of the second quantity

    fac : np.ndarray
        Numpy array with values of the common factor

    fac_unc : np.ndarray
        Numpy array with uncertainties of the common factor

    Returns
    -------
    The correlation coefficients between two quantities f and g
    """
    # calculate the covariance between f and g
    # cov(f,g) = (df/dfac) * (dg/dfac) * fac_unc**2
    # in this case f=x/fac, g=y/fac
    # so cov(f,g) = f * g * fac_unc**2 / fac**2
    cov = f * g * fac_unc ** 2 / fac ** 2

    # calculate and return the correlation coefficient between f and g
    # corr = cov(f,g) / (f_unc * g_unc)
    return cov / (f_unc * g_unc)


def plot_inv_rv_dep(
    outpath,
    inv_RVs,
    alavs,
    alav_uncs,
    waves,
    plot_waves,
    slopes,
    intercepts,
    dense,
    norm="V",
):
    """
    Plot the relationship between A(lambda)/A(V) and 1/R(V)-1/3.1 at wavelengths "plot_waves"

    Parameters
    ----------
    outpath : string
        Path to save the plot

    inv_RVs : np.ndarray
        Numpy array with 1/R(V) values and uncertainties

    alavs : np.ndarray
        Numpy array with A(lambda)/A(V) values

    alav_uncs : np.ndarray
        Numpy array with A(lambda)/A(V) uncertainties

    waves : np.ndarray
        Numpy array with all wavelengths for which A(lambda)/A(V) is given

    plot_waves : list
        List with wavelengths for which to plot the relationship

    slopes : np.ndarray
        Numpy array with the slopes of the linear relationship

    intercepts : np.ndarray
        Numpy array with the intercepts of the linear relationship

    dense : list of booleans
        Whether or not the sightline is dense

    norm : string [default="V"]
        Band or wavelength for the normalization

    Returns
    -------
    Plot of A(lambda)/A(V) vs. 1/R(V)-1/3.1 at wavelengths "plot_waves"
    """
    fig, ax = plt.subplots(
        len(plot_waves), figsize=(7, len(plot_waves) * 4), sharex=True
    )
    if norm != "V":
        norm = str(norm) + r"\mu m"

    for j, wave in enumerate(plot_waves):
        indx = np.abs(waves - wave).argmin()
        # plot the data and the fitted line, give the dense sightlines a different color and marker
        handle1 = ax[j].errorbar(
            inv_RVs[dense][:, 0] - 1 / 3.1,
            alavs[indx][dense],
            xerr=(
                inv_RVs[dense][:, 1],
                inv_RVs[dense][:, 2],
            ),
            yerr=alav_uncs[indx][dense],
            ms=5,
            fmt="s",
            color="magenta",
            elinewidth=0.5,
        )
        handle2 = ax[j].errorbar(
            inv_RVs[~dense][:, 0] - 1 / 3.1,
            alavs[indx][~dense],
            xerr=(
                inv_RVs[~dense][:, 1],
                inv_RVs[~dense][:, 2],
            ),
            yerr=alav_uncs[indx][~dense],
            ms=5,
            fmt="ok",
            elinewidth=0.5,
        )
        xs = np.arange(-0.155, 0.12, 0.01)
        ax[j].plot(
            xs,
            slopes[indx] * xs + intercepts[indx],
            color="forestgreen",
            ls="-",
            label=r"$%5.3f\, %+5.3f\, [1/R(V)-1/3.1]$"
            % (intercepts[indx], slopes[indx]),
        )
        ax[j].set_ylabel(r"$A(" + "{:1.2f}".format(wave) + "\mu m)/A(" + norm + ")$")
        ax[j].legend(loc="lower left", fontsize=fs * 0.8)

        # add literature curves, only if normalized to A(V)
        if norm == "V":
            styles = ["--", ":"]
            for i, cmodel in enumerate([CCM89, F19]):
                if wave > 3.3:
                    continue
                yvals = []
                for xval in xs:
                    ext_model = cmodel(Rv=1 / (xval + 1 / 3.1))
                    yvals.append(ext_model(wave * u.micron))
                ax[j].plot(
                    xs,
                    yvals,
                    lw=1.5,
                    ls=styles[i],
                    alpha=0.8,
                )
            line_handles = [
                Line2D([0], [0], color="tab:blue", lw=1.5, ls="--"),
                Line2D([0], [0], color="tab:orange", lw=1.5, ls=":"),
            ]
            line_labels = [
                "Cardelli et al. (1989)",
                "Fitzpatrick et al. (2019)",
            ]

    # finalize the plot
    plt.xlabel(r"$\frac{1}{R(V)} - \frac{1}{3.1}$", fontsize=fs * 1.3)
    plt.subplots_adjust(hspace=0)
    handles = [handle1, handle2]
    labels = ("dense", "diffuse")
    fig.legend(handles, labels, bbox_to_anchor=(0.4, 0.19), fontsize=fs * 0.8)
    if norm == "V":
        fig.legend(
            line_handles, line_labels, bbox_to_anchor=(0.65, 0.8), fontsize=fs * 0.8
        )
    plt.savefig(
        outpath + "inv_RV_dep" + norm.split("\\")[0] + ".pdf", bbox_inches="tight"
    )


def table_inv_rv_dep(
    outpath, table_waves, fit_slopes, fit_intercepts, fit_stds, norm="V"
):
    """
    Create tables with the slopes, intercepts and standard deviations at wavelengths "table_waves", and the measured and fitted average extinction curve

    Parameters
    ----------
    outpath : string
        Path to save the table

    table_waves : list
        List with wavelengths to be included in the table

    fit_slopes : tuple
        The interpolated spline for the slopes

    fit_intercepts : astropy model
        The fitted model for the intercepts

    fit_stds : tuple
        The interpolated spline for the standard deviations

    norm : string [default="V"]
        Band or wavelength for the normalization

    Returns
    -------
    Tables of the R(V)-dependent relationship at wavelengths "table_waves":
        - in aaxtex format for the paper
        - in ascii format
    """
    # obtain the slopes, intercepts and standard deviations at the table wavelengths
    table_slopes = interpolate.splev(table_waves, fit_slopes)
    table_intercepts = fit_intercepts(table_waves)
    table_stds = interpolate.splev(table_waves, fit_stds)

    # obtain the measured average extinction curve
    average = ExtData(inpath + "average_ext.fits")
    (ave_waves, exts, exts_unc) = average.get_fitdata(["SpeX_SXD", "SpeX_LXD"])
    indx = np.argsort(ave_waves)
    ave_waves = ave_waves[indx].value
    exts = exts[indx]
    exts_unc = exts_unc[indx]

    # create wavelength bins and calculate the binned median extinction and uncertainty
    bin_edges = np.insert(table_waves + 0.025, 0, table_waves[0] - 0.025)
    meds, edges, indices = stats.binned_statistic(
        ave_waves,
        (exts, exts_unc),
        statistic="median",
        bins=bin_edges,
    )

    # obtain the fitted average extinction curve
    ave_fit = average.model["params"][0] * table_waves ** (-average.model["params"][2])

    # obtain the measured average extinction in a few photometric bands
    bands = ["J", "H", "K", "WISE1", "L", "IRAC1"]
    band_waves = [1.22, 1.63, 2.19, 3.35, 3.45, 3.52]
    band_ave = get_phot(ave_waves, exts, bands)
    band_ave_unc = get_phot(ave_waves, exts_unc, bands)

    # obtain the fitted average extinction in a few photometric bands
    all_waves = np.arange(0.8, 4.05, 0.001)

    ave_fit_all = average.model["params"][0] * all_waves ** (
        -average.model["params"][2]
    )
    band_ave_fit = get_phot(all_waves, ave_fit_all, bands)

    # obtain the slopes, intercepts and standard deviations in a few photometric bands
    band_slopes = get_phot(all_waves, -interpolate.splev(all_waves, fit_slopes), bands)
    band_intercepts = get_phot(all_waves, fit_intercepts(all_waves), bands)
    band_stds = get_phot(all_waves, interpolate.splev(all_waves, fit_stds), bands)

    # create the table
    table = Table(
        [
            np.concatenate((band_waves, table_waves)),
            np.concatenate((band_ave, meds[0])),
            np.concatenate((band_ave_unc, meds[1])),
            np.concatenate((band_ave_fit, ave_fit)),
            np.concatenate((band_intercepts, table_intercepts)),
            np.concatenate((-band_slopes, table_slopes)),
            np.concatenate((band_stds, table_stds)),
        ],
        names=(
            "wavelength[micron]",
            "ave",
            "ave_unc",
            "ave_fit",
            "intercept",
            "slope",
            "std",
        ),
    )

    # save it in ascii format
    table.write(
        outpath + "inv_RV_dep" + str(norm) + ".txt",
        format="ascii.commented_header",
        overwrite=True,
    )

    # save it in aastex format
    table.write(
        outpath + "inv_RV_dep" + str(norm) + ".tex",
        format="aastex",
        names=(
            r"$\lambda\ [\micron]$",
            r"$\frac{A(\lambda)}{A(V)}$",
            "unc",
            "fit",
            r"$a(\lambda$)",
            r"$b(\lambda$)",
            r"$\sigma(\lambda)$",
        ),
        formats={
            r"$\lambda\ [\micron]$": "{:.2f}",
            r"$\frac{A(\lambda)}{A(V)}$": "{:.3f}",
            "unc": "{:.3f}",
            "fit": "{:.3f}",
            r"$a(\lambda$)": "{:.3f}",
            r"$b(\lambda$)": "{:.3f}",
            r"$\sigma(\lambda)$": "{:.3f}",
        },
        latexdict={
            "col_align": "c|ccc|ccc",
            "tabletype": "deluxetable",
            "caption": r"Average diffuse Milky Way extinction curve and parameters of the linear relationship between extinction $A(\lambda)/A(V)$ and $1/R(V)$. \label{tab:RV_dep}",
        },
        fill_values=[("nan", r"\nodata")],
        overwrite=True,
    )


def table_spline(outpath, waves, slopes, stds, norm):
    """
    Create a table with the achor points of the spline interpolation

    Parameters
    ----------
    outpath : string
        Path to save the table

    waves : np.ndarray
        Numpy array with anchor wavelengths

    slopes : np.ndarray
        Numpy array with anchor slopes

    stds : np.ndarray
        Numpy array with anchor standard deviations

    norm : string [default="V"]
        Band or wavelength for the normalization

    Returns
    -------
    Table with the anchor points of the spline interpolation (in ascii format)
    """
    # create the table
    table = Table(
        [waves, slopes, stds],
        names=(
            "wavelength[micron]",
            "slope",
            "std",
        ),
    )

    # save it in ascii format
    table.write(
        outpath + "inv_RV_anchors" + str(norm) + ".txt",
        format="ascii.commented_header",
        overwrite=True,
    )


def fit_slopes_intercepts(slopes, intercepts, stds, waves, norm):
    """
    Fit the slopes, intercepts and standard deviations vs. wavelength

    Parameters
    ----------
    slopes : np.ndarray
        Numpy array with the slopes of the linear relationship

    intercepts : np.ndarray
        Numpy array with the intercepts of the linear relationship

    stds : np.ndarray
        Numpy array with the standard deviations about the linear fit

    waves : np.ndarray
        Numpy array with all wavelengths

    norm : string [default="V"]
        Band or wavelength for the normalization

    Returns
    -------
    spline_wave : np.ndarray
        Numpy array with the anchor wavelengths

    spline_slope : np.ndarray
        Numpy array with the anchor slopes

    spline_std : np.ndarray
        Numpy array with the anchor standard deviations

    fit_slopes : tuple
        The interpolated spline for the slopes

    fit_intercepts : astropy model
        The fitted model for the intercepts

    fit_stds : tuple
        The interpolated spline for the standard deviations
    """
    # define a mask for the good data
    mask = ~np.isnan(slopes)
    short_wave_mask = waves < 4.1

    # fit the intercepts with a power law
    fit_lev = fitting.LevMarLSQFitter()
    powerlaw = models.PowerLaw1D(fixed={"x_0": True})
    fit_intercepts = fit_lev(powerlaw, waves[mask], intercepts[mask])

    # define the anchor points for the spline interpolation
    # divide the data into 25 bins with the same number of data points in every bin
    alloc, bin_edges = pd.qcut(waves[mask * short_wave_mask], q=25, retbins=True)
    # calculate the median wavelength, slope and standard deviation in every bin
    meds, edges, indices = stats.binned_statistic(
        waves[mask * short_wave_mask],
        (
            waves[mask * short_wave_mask],
            slopes[mask * short_wave_mask],
            stds[mask * short_wave_mask],
        ),
        statistic="median",
        bins=bin_edges,
    )

    # use the median values as the anchor points for the spline interpolation
    spline_wave = meds[0][~np.isnan(meds[0])]
    spline_slope = meds[1][~np.isnan(meds[1])]
    spline_std = meds[2][~np.isnan(meds[2])]

    # interpolate the slopes with a spline function
    fit_slopes = interpolate.splrep(spline_wave, spline_slope)

    # interpolate the standard deviations with a spline function
    fit_stds = interpolate.splrep(spline_wave, spline_std)

    # create tables with the fitting results at certain wavelengths
    table_waves = np.arange(0.8, 4.05, 0.05)
    table_inv_rv_dep(
        table_path, table_waves, fit_slopes, fit_intercepts, fit_stds, norm
    )

    # create a table with the anchor points of the spline interpolation
    table_spline(table_path, spline_wave, spline_slope, spline_std, norm)

    return spline_wave, spline_slope, spline_std, fit_slopes, fit_intercepts, fit_stds


def plot_inv_RV_lit(outpath, fit_slopes, fit_intercepts, fit_stds):
    """
    Plot the R(V)-dependent extinction curve for different R(V) values, together with R(V)-dependent curves from the literature

    Parameters
    ----------
    outpath : string
        Path to save the plot

    fit_slopes : tuple
        The interpolated spline for the slopes

    fit_intercepts : astropy model
        The fitted model for the intercepts

    Returns
    -------
    Plot with the R(V)-dependent extinction curve for different R(V) values
    """
    waves = np.arange(0.8, 4.01, 0.001)
    fig, ax = plt.subplots(figsize=(10, 9))

    for i, RV in enumerate([2.5, 3.1, 5.5]):
        # plot the extinction curve from this work
        offset = 0.1 * i
        slopes = interpolate.splev(waves, fit_slopes)
        alav = fit_intercepts(waves) + slopes * (1 / RV - 1 / 3.1)
        (line,) = ax.plot(waves, alav + offset, lw=1.5, label=r"$R(V) = $" + str(RV))
        stddev = interpolate.splev(waves, fit_stds)
        color = line.get_color()
        ax.fill_between(
            waves,
            alav + offset - stddev,
            alav + offset + stddev,
            color=color,
            alpha=0.2,
            edgecolor=None,
        )

        # plot the literature curves
        styles = ["--", ":"]
        for i, cmodel in enumerate([CCM89, F19]):
            ext_model = cmodel(Rv=RV)
            (indxs,) = np.where(
                np.logical_and(
                    1 / waves >= ext_model.x_range[0], 1 / waves <= ext_model.x_range[1]
                )
            )
            yvals = ext_model(waves[indxs] * u.micron)
            ax.plot(
                waves[indxs],
                yvals + offset,
                lw=1.5,
                color=color,
                ls=styles[i],
                alpha=0.8,
            )

    # add text
    ax.text(3.45, 0.03, r"$R(V) = 2.5$", fontsize=0.8 * fs, color="tab:blue")
    ax.text(3.45, 0.15, r"$R(V) = 3.1$", fontsize=0.8 * fs, color="tab:orange")
    ax.text(3.45, 0.305, r"$R(V) = 5.5$", fontsize=0.8 * fs, color="tab:green")

    # finalize and save the plot
    ax.set_xlabel(r"$\lambda\ [\mu m$]", fontsize=1.2 * fs)
    ax.set_ylabel(r"$A(\lambda)/A(V)$ + offset", fontsize=1.2 * fs)
    ax.set_xlim(0.75, 4.05)
    ax.set_ylim(-0.03, 0.98)
    handles = [
        Line2D([0], [0], color="k", lw=1.5),
        Line2D([0], [0], color="k", lw=1.5, ls="--"),
        Line2D([0], [0], color="k", lw=1.5, ls=":"),
    ]
    labels = [
        "this work",
        "Cardelli et al. (1989)",
        "Fitzpatrick et al. (2019)",
    ]
    plt.legend(handles, labels, fontsize=fs)
    plt.savefig(outpath + "inv_RV_lit.pdf", bbox_inches="tight")

    # also save the plot in log scale
    plt.ylim(0.01, 1)
    plt.yscale("log")
    plt.tight_layout()
    plt.savefig(outpath + "inv_RV_lit_log.pdf")


def fit_plot_inv_rv_dep(
    inpath, plot_path, table_path, starpair_list_diff, starpair_list_dense, norm="V"
):
    """
    Fit and plot the relationship between A(lambda)/A(V) and 1/R(V)

    Parameters
    ----------
    inpath : string
        Path to the input data files

    plot_path : string
        Path to save the plots

    table_path : string
        Path to save the table

    starpair_list_diffuse : list of strings
        List of diffuse star pairs to include in the fitting, in the format "reddenedstarname_comparisonstarname" (no spaces)

    starpair_list_dense : list of strings
        List of dense star pairs to include in the fitting, in the format "reddenedstarname_comparisonstarname" (no spaces)

    norm : string [default="V"]
        Band or wavelength for the normalization

    Returns
    -------
    Several plots related to the R(V)-dependence
    """
    # collect the data to be fitted
    inv_RVs, AVs, alavs, alav_uncs, waves, dense_bool = get_data(
        inpath, starpair_list_diff, starpair_list_dense, norm
    )
    inv_RV_vals = inv_RVs[:, 0]
    inv_RV_uncs = (inv_RVs[:, 1] + inv_RVs[:, 2]) / 2
    AV_vals = AVs[:, 0]
    AV_uncs = (AVs[:, 1] + AVs[:, 2]) / 2

    # for every wavelength, fit a straight line through the A(lambda)/A(V) vs. 1/R(V)-1/3.1 data
    fit = fitting.LinearLSQFitter()
    line_func = models.Linear1D()
    slopes, intercepts, stds = np.full((3, len(waves)), np.nan)
    corr_list = []

    for j, wave in enumerate(waves):
        mask = ~np.isnan(alavs[j])
        npts = np.sum(mask)
        # require at least 5 data points for the fitting
        if npts < 5:
            continue
        fitted_line = fit(
            line_func,
            (inv_RV_vals[mask] - 1 / 3.1),
            alavs[j][mask],
            weights=1 / alav_uncs[j][mask],
        )
        # calculate the standard deviation about the fit
        # the "residuals" in the fit_info is the sum of the squared residuals
        # std = np.sqrt(fit.fit_info["residuals"] / (npts - 2))
        # this does not work when using weights in the fitting
        # dividing by npts-2 is needed, because there are npts-2 degrees of freedom (subtract 1 for the slope and 1 for the intercept)
        std = np.sqrt(
            np.sum((fitted_line(inv_RV_vals[mask] - 1 / 3.1) - alavs[j][mask]) ** 2)
            / (npts - 2)
        )
        slopes[j] = fitted_line.slope.value
        intercepts[j] = fitted_line.intercept.value
        stds[j] = std

        # calculate the correlation coefficient between A(lambda)/A(V) and 1/R(V) for every sightline, and find out the range in correlation coefficients and the median value over all sightlines and all wavelengths
        corr = calc_corr(
            alavs[j][mask],
            alav_uncs[j][mask],
            inv_RV_vals[mask],
            inv_RV_uncs[mask],
            AV_vals[mask],
            AV_uncs[mask],
        )
        for value in corr:
            corr_list.append(value)

    # print information about the correlation coefficients
    print(
        "Minimum, median and maximum correlation coefficients: ",
        np.min(corr_list),
        np.median(corr_list),
        np.max(corr_list),
    )

    # plot A(lambda)/A(V) vs. 1/R(V) at certain wavelengths
    plot_waves = [0.89864296, 1.6499686, 2.4527225, 3.5002365, 4.697073]
    plot_inv_rv_dep(
        plot_path,
        inv_RVs,
        alavs,
        alav_uncs,
        waves,
        plot_waves,
        slopes,
        intercepts,
        dense_bool,
        norm=norm,
    )

    # plot the slopes, intercepts and standard deviations vs. wavelength
    # color the data points at wavelengths > 4.03 gray
    fig, ax = plt.subplots(3, figsize=(9, 9), sharex=True)
    short_waves = (waves > 0.809) & (waves < 4.02)
    ms = 0.8
    ax[0].scatter(waves, intercepts, color="k", s=ms)
    ax[1].scatter(waves[short_waves], slopes[short_waves], color="k", s=ms)
    ax[1].scatter(waves[~short_waves], slopes[~short_waves], color="gray", s=ms)
    ax[2].scatter(waves[short_waves], stds[short_waves], color="k", s=ms)
    ax[2].scatter(waves[~short_waves], stds[~short_waves], color="gray", s=ms)
    for wave in plot_waves:
        indx = np.abs(waves - wave).argmin()
        ax[0].scatter(wave, intercepts[indx], color="lime", s=50, marker="x", zorder=3)
        ax[1].scatter(wave, slopes[indx], color="lime", s=50, marker="x", zorder=3)
        ax[2].scatter(wave, stds[indx], color="lime", s=50, marker="x", zorder=3)

    # fit the slopes, intercepts and standard deviations vs. wavelength, and add the fit to the plot
    (
        spline_wave,
        spline_slope,
        spline_std,
        fit_slopes,
        fit_intercepts,
        fit_stds,
    ) = fit_slopes_intercepts(slopes, intercepts, stds, waves, norm)

    ax[0].plot(
        waves,
        fit_intercepts(waves),
        color="crimson",
        ls="--",
        alpha=0.9,
        label=r"$%5.3f \ \lambda ^{-%5.2f}$"
        % (fit_intercepts.amplitude.value, fit_intercepts.alpha.value),
    )

    slope_spline = interpolate.splev(waves[short_waves], fit_slopes)
    ax[1].scatter(spline_wave, spline_slope, color="r", marker="d", s=15)
    ax[1].plot(
        waves[short_waves],
        slope_spline,
        color="crimson",
        ls="--",
        alpha=0.9,
    )

    std_spline = interpolate.splev(waves[short_waves], fit_stds)
    ax[2].scatter(spline_wave, spline_std, color="r", marker="d", s=10)
    ax[2].plot(
        waves[short_waves],
        std_spline,
        color="crimson",
        ls="--",
        alpha=0.9,
    )

    # finalize and save the plot
    ax[0].legend(fontsize=fs)
    plt.xlabel(r"$\lambda\ [\mu m$]", fontsize=1.2 * fs)
    plt.xlim(0.75, 5.2)
    ax[0].set_ylim(-0.03, 0.6)
    ax[1].set_ylim(-1.1, 0.2)
    ax[2].set_ylim(0.005, 0.075)
    ax[0].set_ylabel(r"$a$", fontsize=1.2 * fs)
    ax[1].set_ylabel(r"$b$", fontsize=1.2 * fs)
    ax[2].set_ylabel(r"$\sigma$", fontsize=1.2 * fs)
    ax[0].axhline(ls="--", color="k", lw=1, alpha=0.6)
    ax[1].axhline(ls="--", color="k", lw=1, alpha=0.6)
    plt.subplots_adjust(hspace=0)
    plt.savefig(
        plot_path + "inv_RV_slope_inter" + str(norm) + ".pdf", bbox_inches="tight"
    )

    # plot the residuals of the intercepts and add the residuals from the average extinction curve fitting
    res_inter = intercepts - fit_intercepts(waves)
    average = ExtData(inpath + "average_ext.fits")
    wave_ave = average.model["waves"]
    res_ave = average.model["residuals"]
    fig, ax = plt.subplots(figsize=(10, 7))
    ax.scatter(waves, res_inter, s=1.5, color="k", alpha=0.8, label="intercepts")
    ax.scatter(wave_ave, res_ave, s=1.5, color="r", alpha=0.8, label="average")
    ax.axhline()
    plt.xlabel(r"$\lambda\ [\mu m$]")
    plt.ylabel(r"residual extinction")
    plt.ylim(-0.026, 0.026)
    plt.legend()
    plt.savefig(plot_path + "inv_inter_res" + str(norm) + ".pdf", bbox_inches="tight")

    # compare R(V)-dependent extinction curves to literature curves
    # only useful for extinction curves that are normalized to A(V)
    if norm == "V":
        plot_inv_RV_lit(plot_path, fit_slopes, fit_intercepts, fit_stds)


if __name__ == "__main__":
    # define the input and output path and the names of the star pairs in the format "reddenedstarname_comparisonstarname"
    inpath = "/Users/mdecleir/Documents/NIR_ext/Data/"
    plot_path = "/Users/mdecleir/spex_nir_extinction/Figures/"
    table_path = "/Users/mdecleir/spex_nir_extinction/Tables/"
    diffuse = [
        "BD+56d524_HD034816",
        "HD013338_HD031726",
        "HD014250_HD031726",
        "HD014422_HD214680",
        "HD014956_HD214680",
        "HD017505_HD214680",
        "HD029309_HD042560",
        "HD034921_HD214680",
        "HD037020_HD034816",
        "HD037022_HD034816",
        "HD037023_HD036512",
        "HD037061_HD034816",
        "HD038087_HD051283",
        "HD052721_HD091316",
        "HD156247_HD042560",
        "HD166734_HD031726",
        "HD183143_HD188209",
        "HD185418_HD034816",
        "HD192660_HD214680",
        "HD204827_HD003360",
        "HD206773_HD047839",
        "HD229238_HD214680",
        "HD294264_HD051283",
    ]

    dense = ["HD029647_HD034759", "HD283809_HD003360"]

    # list the problematic star pairs
    flagged = [
        "HD014250_HD031726",
        "HD014422_HD214680",
        "HD034921_HD214680",
        "HD037020_HD034816",
        "HD037022_HD034816",
        "HD037023_HD036512",
        "HD052721_HD091316",
        "HD166734_HD031726",
        "HD206773_HD047839",
        "HD294264_HD051283",
    ]

    # settings for the plotting
    fs = 20
    plt.rc("font", size=fs)
    plt.rc("xtick.major", width=1, size=10)
    plt.rc("ytick.major", width=1, size=10)
    plt.rc("xtick", top=True, direction="in", labelsize=fs * 0.8)
    plt.rc("ytick", right=True, direction="in", labelsize=fs * 0.8)

    # subtract the flagged stars from the star pair lists
    good_diffuse = list((Counter(diffuse) - Counter(flagged)).elements())
    good_dense = list((Counter(dense) - Counter(flagged)).elements())

    # fit and plot the RV dependence
    fit_plot_inv_rv_dep(inpath, plot_path, table_path, good_diffuse, good_dense)

    # fit and plot the RV dependence when normalizing to 1 micron instead of to the V-band
    # fit_plot_inv_rv_dep(inpath, plot_path, table_path, good_diffuse, good_dense, norm=1)

    # ------------------------------------------------------------------
    # EXTRA (eventually not used in the paper)

    # add CCM89 1/RV dependent relation (can only be used with 1/RV)
    # waves_CCM89 = [0.7, 0.9, 1.25, 1.6, 2.2, 3.4]
    # slopes_CCM89 = [-0.366, -0.6239, -0.3679, -0.2473, -0.1483, -0.0734]
    # intercepts_CCM89 = [0.8686, 0.68, 0.4008, 0.2693, 0.1615, 0.08]
    # ax[0].scatter(waves_CCM89, slopes_CCM89, s=5)
    # ax[1].scatter(waves_CCM89, intercepts_CCM89, s=5)