diff options
Diffstat (limited to 'fg21sim/extragalactic')
| -rw-r--r-- | fg21sim/extragalactic/__init__.py | 4 | ||||
| -rw-r--r-- | fg21sim/extragalactic/clusters.py | 650 |
2 files changed, 654 insertions, 0 deletions
diff --git a/fg21sim/extragalactic/__init__.py b/fg21sim/extragalactic/__init__.py new file mode 100644 index 0000000..af976ca --- /dev/null +++ b/fg21sim/extragalactic/__init__.py @@ -0,0 +1,4 @@ +# Copyright (c) 2016 Weitian LI <liweitianux@live.com> +# MIT license + +from .clusters import GalaxyClusters diff --git a/fg21sim/extragalactic/clusters.py b/fg21sim/extragalactic/clusters.py new file mode 100644 index 0000000..b20d261 --- /dev/null +++ b/fg21sim/extragalactic/clusters.py @@ -0,0 +1,650 @@ +# Copyright (c) 2016 Weitian LI <liweitianux@live.com> +# MIT license + +""" +Simulation of the radio emissions from clusters of galaxies. + +NOTE +---- +Currently, only radio *halos* are considered with many simplifications. +Radio *relics* simulations need more investigations ... +""" + +import os +import logging +from datetime import datetime, timezone + +import numpy as np +import astropy.units as au +from astropy.io import fits +from astropy.cosmology import FlatLambdaCDM +import healpy as hp +import pandas as pd + +from ..utils import write_fits_healpix +from ..utils.random import spherical_uniform +from ..utils.convert import Fnu_to_Tb +from ..utils.grid import make_grid_ellipse, map_grid_to_healpix + + +logger = logging.getLogger(__name__) + + +class GalaxyClusters: + """ + Simulate the radio emissions from the clusters of galaxies, which + host radio halos and relics (currently not considered). + + The simulation follows the method adopted by [Jelic2008]_, which uses + the *ΛCDM deep wedge cluster catalog* derived from the *Hubble Volume + Project* [HVP]_, [Evard2002]_. + + Every radio cluster is simulated as an *ellipse* of *uniform brightness* + on a local coordinate grid with relatively higher resolution compared + to the output HEALPix map, which is then mapped to the output HEALPix + map by down-sampling, i.e., in a similar way as the simulations of SNRs. + + TODO: ??? + + Parameters + ---------- + configs : `ConfigManager` + A `ConfigManager` instance containing default and user configurations. + For more details, see the example configuration specifications. + + Attributes + ---------- + TODO: ??? + + NOTE + ---- + Currently, only radio *halos* are considered with many simplifications. + Radio *relics* simulations need more investigations ... + + References + ---------- + .. [Jelic2008] + Jelić, V. et al., + "Foreground simulations for the LOFAR-epoch of reionization experiment", + 2008, MNRAS, 389, 1319-1335, + http://adsabs.harvard.edu/abs/2008MNRAS.389.1319J + + .. [Evard2002] + Evard, A. E. et al., + "Galaxy Clusters in Hubble Volume Simulations: Cosmological Constraints + from Sky Survey Populations", + 2002, ApJ, 573, 7-36, + http://adsabs.harvard.edu/abs/2002ApJ...573....7E + + .. [EnBlin2002] + Enßlin, T. A. & Röttgering, H., + "The radio luminosity function of cluster radio halos", + 2002, A&A, 396, 83-89, + http://adsabs.harvard.edu/abs/2002A%26A...396...83E + + .. [Reiprich2002] + Reiprich, Thomas H. & Böhringer, Hans, + "The Mass Function of an X-Ray Flux-limited Sample of Galaxy Clusters", + 2002, ApJ, 567, 716-740, + http://adsabs.harvard.edu/abs/2002ApJ...567..716R + """ + # Component name + name = "clusters of galaxies" + + def __init__(self, configs): + self.configs = configs + self._set_configs() + + def _set_configs(self): + """Load the configs and set the corresponding class attributes.""" + comp = "extragalactic/clusters" + self.catalog_path = self.configs.get_path(comp+"/catalog") + self.catalog_outfile = self.configs.get_path(comp+"/catalog_outfile") + self.halo_fraction = self.configs.getn(comp+"/halo_fraction") + self.resolution = self.configs.getn(comp+"/resolution") * au.arcmin + self.prefix = self.configs.getn(comp+"/prefix") + self.save = self.configs.getn(comp+"/save") + self.output_dir = self.configs.get_path(comp+"/output_dir") + # + self.filename_pattern = self.configs.getn("output/filename_pattern") + self.use_float = self.configs.getn("output/use_float") + self.clobber = self.configs.getn("output/clobber") + self.nside = self.configs.getn("common/nside") + self.freq_unit = au.Unit(self.configs.getn("frequency/unit")) + # Cosmology model + self.H0 = self.configs.getn("cosmology/H0") + self.OmegaM0 = self.configs.getn("cosmology/OmegaM0") + self.cosmo = FlatLambdaCDM(H0=self.H0, Om0=self.OmegaM0) + # + logger.info("Loaded and set up configurations") + + def _load_catalog(self): + """Load the cluster catalog data and set up its properties.""" + self.catalog = pd.read_csv(self.catalog_path) + nrow, ncol = self.catalog.shape + logger.info("Loaded clusters catalog data from: {0}".format( + self.catalog_path)) + logger.info("Clusters catalog data: {0} objects, {1} columns".format( + nrow, ncol)) + # Set the properties for this catalog + self.catalog_prop = { + "omega_m": 0.3, + "omega_lambda": 0.7, + # Dimensionless Hubble constant + "h": 0.7, + "sigma8": 0.9, + # Number of particles + "n_particle": 1e9, + # Particle mass of the simulation [ h^-1 ] + "m_particle": 2.25e12 * au.solMass, + # Cube side length [ h^-1 ] + "l_side": 3000.0 * au.Mpc, + # Overdensity adopted to derive the clusters + "overdensity": 200, + # Sky coverage + "coverage": 10*au.deg * 10*au.deg + } + # Units for the catalog columns (also be populated by other methods) + self.units = {} + + def _save_catalog_inuse(self): + """Save the effective/inuse clusters catalog data to a CSV file.""" + if self.catalog_outfile is None: + logger.warning("Catalog output file not set, so do NOT save.") + return + # Create directory if necessary + dirname = os.path.dirname(self.catalog_outfile) + if not os.path.exists(dirname): + os.mkdir(dirname) + logger.info("Created directory: {0}".format(dirname)) + # Save catalog data + if os.path.exists(self.catalog_outfile): + if self.clobber: + os.remove(self.catalog_outfile) + else: + raise OSError("Output file already exists: {0}".format( + self.catalog_outfile)) + self.catalog.to_csv(self.catalog_outfile, header=True, index=False) + logger.info("Save clusters catalog in use to: {0}".format( + self.catalog_outfile)) + + def _process_catalog(self): + """Process the catalog to prepare for the simulation.""" + # Dimensionless Hubble parameter adopted in THIS simulation + h = self.H0 / 100 + logger.info("Adopted dimensionless Hubble parameter: {0}".format(h)) + # Cluster masses, unit: solMass (NOTE: h dependence) + self.catalog["mass"] = (self.catalog["m"] * + self.catalog_prop["m_particles"].value / h) + self.units["mass"] = au.solMass + logger.info("Catalog: calculated cluster masses") + # Cluster distances from the observer, unit: Mpc + dist = ((self.catalog["x"]**2 + self.catalog["y"]**2 + + self.catalog["z"]**2) ** 0.5 * + self.catalog_prop["l_side"].value / h) + self.catalog["distance"] = dist + self.units["distance"] = au.Mpc + logger.info("Catalog: calculated cluster distances") + # Drop unnecessary columns to save memory + columns_drop = ["m", "sigma", "ip", "x", "y", "z", "vx", "vy", "vz"] + self.catalog.drop(columns_drop, axis=1, inplace=True) + logger.info("Catalog: dropped unnecessary columns: {0}".format( + ", ".join(columns_drop))) + + def _expand_catalog_fullsky(self): + """Expand the catalog to be full sky, by assuming that clusters are + uniformly distributed. Also, the radio halo fraction is also + considered to determine the final number of clusters on the full sky. + """ + fullsky = 4*np.pi * au.sr + factor = float(fullsky / self.catalog_prop["coverage"]) + n0_cluster = len(self.catalog) + logger.info("Halo fraction in clusters: %f" % self.halo_fraction) + # Total number of clusters on the full sky + N_cluster = int(n0_cluster * factor * self.halo_fraction) + logger.info("Total number of clusters on the full sky: {0:,}".format( + N_cluster)) + logger.info("Expanding the catalog to be full sky ...") + idx = np.round(np.random.uniform(low=0, high=n0_cluster-1, + size=N_cluster)).astype(np.int) + self.catalog = self.catalog.iloc[idx, :] + self.catalog.reset_index(inplace=True) + logger.info("Done expand the catalog to be full sky") + + def _add_random_position(self): + """Add random positions for each cluster as columns "glon" and + "glat" to the catalog data. + + Column "glon" is the Galactic longitudes, [0, 360) (degree). + Column "glat" is the Galactic latitudes, [-90, 90] (degree). + + The positions are uniformly distributed on the spherical surface. + """ + logger.info("Randomly generating positions for each cluster ...") + num = len(self.catalog) + theta, phi = spherical_uniform(num) + glon = np.degrees(phi) + glat = 90.0 - np.degrees(theta) + self.catalog["glon"] = glon + self.catalog["glat"] = glat + self.units["coord"] = au.deg + logger.info("Done add random positions for each cluster") + + def _add_random_eccentricity(self): + """Add random eccentricities for each cluster as column + "eccentricity" to the catalog data. + + The eccentricity of a ellipse is defined as: + e = sqrt((a^2 - b^2) / a^2) = f / a + where f is the distance from the center to either focus: + f = sqrt(a^2 - b^2) + + NOTE + ---- + The eccentricities are randomly generated from a *squared* + standard normalization distribution, and with an upper limit + at 0.9, i.e., the eccentricities are [0, 0.9]. + """ + logger.info("Adding random eccentricities for each cluster ...") + num = len(self.catalog) + eccentricity = np.random.normal(size=num) ** 2 + # Replace values beyond the upper limit by sampling from valid values + ulimit = 0.9 + idx_invalid = (eccentricity > ulimit) + num_invalid = idx_invalid.sum() + eccentricity[idx_invalid] = np.random.choice( + eccentricity[~idx_invalid], size=num_invalid) + self.catalog["eccentricity"] = eccentricity + logger.info("Done add random eccentricities to catalog") + + def _add_random_rotation(self): + """Add random rotation angles for each cluster as column "rotation" + to the catalog data. + + The rotation angles are uniformly distributed within [0, 360). + + The rotation happens on the spherical surface, i.e., not with respect + to the line of sight, but to the Galactic frame coordinate axes. + """ + logger.info("Adding random rotation angles for each cluster ...") + num = len(self.catalog) + rotation = np.random.uniform(low=0.0, high=360.0, size=num) + self.catalog["rotation"] = rotation + self.units["rotation"] = au.deg + logger.info("Done add random rotation angles to catalog") + + def _calc_sizes(self): + """Calculate the virial radii for each cluster from the masses, + and then calculate the elliptical angular sizes by considering + the added random eccentricities. + + Attributes + ---------- + catalog["r_vir"] : 1D `~numpy.ndarray` + The virial radii (unit: Mpc) calculated from the cluster masses + catalog["size_major"], catalog["size_minor] : 1D `~numpy.ndarray` + The major and minor axes (unit: degree) of the clusters calculated + from the above virial radii and the random eccentricities. + + NOTE + ---- + The elliptical major and minor axes are calculated by assuming + the equal area between the ellipse and corresponding circle. + theta2 = r_vir / distance + pi * a * b = pi * (theta2)^2 + e = sqrt((a^2 - b^2) / a^2) + thus, + a = theta2 / (1-e^2)^(1/4) + b = theta2 * (1-e^2)^(1/4) + """ + logger.info("Calculating the virial radii ...") + overdensity = self.catalog_prop["overdensity"] + rho_crit = self.cosmo.critical_density(self.catalog["redshift"]) + mass = self.catalog["mass"].data * self.units["mass"] + r_vir = (3 * mass / (4*np.pi * overdensity * rho_crit)) ** (1.0/3.0) + self.catalog["r_vir"] = r_vir.to(au.Mpc).value + self.units["r_vir"] = au.Mpc + logger.info("Done calculate the virial radii") + # Calculate (elliptical) angular sizes, i.e., major and minor axes + logger.info("Calculating the elliptical angular sizes ...") + distance = self.catalog["distance"].data * self.units["distance"] + theta2 = float(2 * r_vir / distance) # [ rad ] + size_major = theta2 / (1 - self.catalog["eccentricity"]**2) ** 0.25 + size_minor = theta2 * (1 - self.catalog["eccentricity"]**2) ** 0.25 + self.catalog["size_major"] = size_major * au.rad.to(au.deg) + self.catalog["size_minor"] = size_minor * au.rad.to(au.deg) + self.units["size"] = au.deg + logger.info("Done calculate the elliptical angular sizes") + + def _calc_luminosity(self): + """Calculate the radio luminosity (at 1.4 GHz) using empirical + scaling relations. + + First, calculate the X-ray luminosity L_X using the empirical + scaling relation between mass and X-ray luminosity. + Then, derive the radio luminosity by employing the scaling + relation between X-ray and radio luminosity. + + XXX/TODO + -------- + The scaling relations used here may be outdated, and some of the + quantities need trick conversions, which cause much confusion. + + Investigate for *more up-to-date scaling relations*, derived with + new observation constraints. + + NOTE + ---- + - The mass in the mass-X-ray luminosity scaling relation is NOT the + cluster real mass, since [Reiprich2002]_ refer to the + *critical density* ρ_c, while the scaling relation from + Jenkins et al. (2001) requires mass refer to the + *cosmic mean mass density ρ_m = Ω_m * ρ_c, + therefore, the mass needs following conversion (which is an + approximation): + M_{R&B} ~= M * sqrt(OmegaM0) + - The derived X-ray luminosity is for the 0.1-2.4 keV energy band. + - The X-ray-radio luminosity scaling relation adopted here is + derived at 1.4 GHz. + - [EnBlin2002]_ assumes H0 = 50 h50 km/s/Mpc, so h50 = 1. + + References + ---------- + - [Jelic2008], Eq.(13,14) + - [EnBlin2002], Eq.(1,3) + """ + # Dimensionless Hubble parameter adopted here and in the literature + h_our = self.H0 / 100 + h_others = 50.0 / 100 + # + logger.info("Calculating the radio luminosity (at 1.4 GHz) ...") + # Calculate the X-ray luminosity from mass + # XXX: why the mass conversion ?? + mass_RB = (self.catalog["mass"].data * self.units["mass"] * + self.catalog_prop["omega_m"]**0.5) + a_X = 0.449 + b_X = 1.9 + # Hubble parameter conversion factor + h_conv1 = (h_our / h_others) ** (b_X-2) + # X-ray luminosity (0.1-2.4 keV) [ erg/s ] + L_X = (a_X * 1e45 * float(mass_RB / (1e15*au.solMass))**b_X) * h_conv1 + # Calculate the radio luminosity from X-ray luminosity + a_r = 2.78 + b_r = 1.94 + # Hubble parameter conversion factor + h_conv2 = (h_our / h_others) ** (2*b_r-2) + # Radio luminosity density (at 1.4 GHz) [ W/Hz ] + L_r = (a_r * 1e24 * (L_X / 1e45)**b_r) * h_conv2 + self.catalog["luminosity"] = L_r + self.catalog_prop["luminosity_freq"] = 1.4 * au.GHz + self.units["luminosity"] = au.W / au.Hz + logger.info("Done Calculate the radio luminosity") + + def _calc_Tb(self, luminosity, distance, specindex, frequency, size): + """Calculate the brightness temperature at requested frequency + by assuming a power-law spectral shape. + + Parameters + ---------- + luminosity : float + The luminosity density (unit: `self.units["luminosity"]`) at + the reference frequency (i.e., + `self.catalog_prop["luminosity_freq"]`). + distance : float + The luminosity distance (unit: `self.units["distance"]`) to the + object + specindex : float + The spectral index of the power-law spectrum. + Note the *negative* sign in the formula. + frequency : float + The frequency (unit: `self.freq_unit`) where the brightness + temperature requested. + size : 2-float tuple + The (major, minor) axes (unit: `self.units["size"]`). + The order of major and minor can be arbitrary. + + Returns + ------- + Tb : float + Brightness temperature at the requested frequency, unit [ K ] + + NOTE + ---- + The power-law spectral shape is assumed for *flux density* other + than the *brightness temperature*. + Therefore, the flux density at the requested frequency should first + be calculated by extrapolating the spectrum, then convert the flux + density to derive the brightness temperature. + """ + freq = frequency * self.freq_unit + freq_ref = self.catalog_prop["luminosity_freq"] + luminosity = luminosity * self.units["luminosity"] + Lnu = luminosity * float(freq / freq_ref) ** (-specindex) + Fnu = Lnu / (4*np.pi * (distance*self.units["distance"])**2) + omega = size[0]*self.units["size"] * size[1]*self.units["size"] + Tb = Fnu_to_Tb(Fnu, omega, freq) + return Tb.value + + def _simulate_templates(self): + """Simulate the template (HEALPix) images for each cluster, and + cache these templates within the class. + + The template images/maps have values of (or approximate) ones for + these effective pixels, excluding the pixels corresponding to the + edges of original rotated ellipse, which may have values of + significantly less than 1 due to the rotation. + + Therefore, simulating the HEALPix map of one cluster at a requested + frequency is simply multiplying the cached template image by the + calculated brightness temperature (Tb) at that frequency. + + Furthermore, the total HEALPix map of all clusters are straightforward + additions of all the maps of each cluster. + + Attributes + ---------- + templates : list + A List containing the simulated templates for each cluster. + Each element is a `(hpidx, hpval)` tuple with `hpidx` the + indexes of effective HEALPix pixels (RING ordering) and `hpval` + the values of the corresponding pixels. + e.g., ``[ (hpidx1, hpval1), (hpidx2, hpval2), ... ]`` + """ + logger.info("Simulating HEALPix templates for each cluster ...") + templates = [] + resolution = self.resolution.to(au.deg).value + # XXX/TODO: be parallel + for row in self.catalog.itertuples(): + # TODO: progress bar + center = (row.glon, row.glat) + size = (row.size_major, row.size_minor) # already [ degree ] + rotation = row.rotation # already [ degree ] + grid = make_grid_ellipse(center, size, resolution, rotation) + hpidx, hpval = map_grid_to_healpix(grid, self.nside) + templates.append((hpidx, hpval)) + logger.info("Done simulate %d cluster templates" % len(templates)) + self.templates = templates + + def _simulate_single(self, data, frequency): + """Simulate one single cluster at the specified frequency, based + on the cached template image. + + Parameters + ---------- + data : namedtuple + The data of the SNR to be simulated, given in a ``namedtuple`` + object, from which can get the required properties by + ``data.key``. + e.g., elements of `self.catalog.itertuples()` + frequency : float + The simulation frequency (unit: `self.freq_unit`). + + Returns + ------- + hpidx : 1D `~numpy.ndarray` + The indexes (in RING ordering) of the effective HEALPix + pixels for the SNR. + hpval : 1D `~numpy.ndarray` + The values (i.e., brightness temperature) of each HEALPix + pixel with respect the above indexes. + + See Also + -------- + `self._simulate_template()` for more detailed description. + """ + name = data.name + hpidx, hpval = self.templates[name] + # Calculate the brightness temperature + luminosity = data.luminosity + distance = data.distance + specindex = data.specindex + size = (data.size_major, data.size_minor) + Tb = self._calc_Tb(luminosity, distance, specindex, frequency, size) + hpval = hpval * Tb + return (hpidx, hpval) + + def _make_filepath(self, **kwargs): + """Make the path of output file according to the filename pattern + and output directory loaded from configurations. + """ + data = { + "prefix": self.prefix, + } + data.update(kwargs) + filename = self.filename_pattern.format(**data) + filetype = self.configs.getn("output/filetype") + if filetype == "fits": + filename += ".fits" + else: + raise NotImplementedError("unsupported filetype: %s" % filetype) + filepath = os.path.join(self.output_dir, filename) + return filepath + + def _make_header(self): + """Make the header with detail information (e.g., parameters and + history) for the simulated products. + """ + header = fits.Header() + header["COMP"] = ("extragalactic clusters of galaxies (radio halos)", + "Emission component") + header["UNIT"] = ("Kelvin", "Map unit") + header["CREATOR"] = (__name__, "File creator") + # TODO: + history = [] + comments = [] + for hist in history: + header.add_history(hist) + for cmt in comments: + header.add_comment(cmt) + self.header = header + logger.info("Created FITS header") + + def output(self, hpmap, frequency): + """Write the simulated free-free map to disk with proper header + keywords and history. + """ + if not os.path.exists(self.output_dir): + os.mkdir(self.output_dir) + logger.info("Created output dir: {0}".format(self.output_dir)) + # + filepath = self._make_filepath(frequency=frequency) + if not hasattr(self, "header"): + self._make_header() + header = self.header.copy() + header["FREQ"] = (frequency, "Frequency [ MHz ]") + header["DATE"] = ( + datetime.now(timezone.utc).astimezone().isoformat(), + "File creation date" + ) + if self.use_float: + hpmap = hpmap.astype(np.float32) + write_fits_healpix(filepath, hpmap, header=header, + clobber=self.clobber) + logger.info("Write simulated map to file: {0}".format(filepath)) + + def preprocess(self): + """Perform the preparation procedures for the final simulations. + + Attributes + ---------- + _preprocessed : bool + This attribute presents and is ``True`` after the preparation + procedures are performed, which indicates that it is ready to + do the final simulations. + """ + if hasattr(self, "_preprocessed") and self._preprocessed: + return + # + logger.info("{name}: preprocessing ...".format(name=self.name)) + self._load_catalog() + self._process_catalog() + # + self._expand_catalog_fullsky() + self._add_random_position() + self._add_random_eccentricity() + self._add_random_rotation() + # + self._calc_sizes() + self._calc_luminosity() + # + self._simulate_templates() + # + self._preprocessed = True + + def simulate_frequency(self, frequency): + """Simulate the emission (HEALPix) map of all Galactic SNRs at + the specified frequency. + + Parameters + ---------- + frequency : float + The simulation frequency (unit: `self.freq_unit`). + + Returns + ------- + hpmap_f : 1D `~numpy.ndarray` + HEALPix map data in RING ordering + + See Also + -------- + `self._simulate_template()` for more detailed description. + """ + self.preprocess() + # + logger.info("Simulating {name} map at {freq} ({unit}) ...".format( + name=self.name, freq=frequency, unit=self.freq_unit)) + hpmap_f = np.zeros(hp.nside2npix(self.nside)) + for row in self.catalog.itertuples(): + hpidx, hpval = self._simulate_single(row, frequency) + hpmap_f[hpidx] += hpval + # + if self.save: + self.output(hpmap_f, frequency) + return hpmap_f + + def simulate(self, frequencies): + """Simulate the emission (HEALPix) maps of all Galactic SNRs for + every specified frequency. + + Parameters + ---------- + frequency : list[float] + List of frequencies (unit: `self.freq_unit`) where the + simulation performed. + + Returns + ------- + hpmaps : list[1D `~numpy.ndarray`] + List of HEALPix maps (in RING ordering) at each frequency. + """ + hpmaps = [] + for f in np.array(frequencies, ndmin=1): + hpmap_f = self.simulate_frequency(f) + hpmaps.append(hpmap_f) + return hpmaps + + def postprocess(self): + """Perform the post-simulation operations before the end.""" + logger.info("{name}: postprocessing ...".format(name=self.name)) + # Save the catalog actually used in the simulation + self._save_catalog_inuse() |