这是在天文学中,但我认为我的问题可能非常初级——我不是很有经验,我很抱歉。
我正在绘制恒星形成星系的颜色(y 轴)与红移(x 轴)之间的关系。该图是一条从大约 0 上升到大约 9 的线,然后再次衰减到大约 -2。就红移而言,峰值(~9 颜色)约为 4,我想更准确地找到峰值。红移是由一个相当令人困惑的函数给出的,我不知道如何区分它,否则我只会这样做。
我可以区分复杂的红移(z)函数吗?如果是这样,怎么做?
如果不是,我如何以图形/数字方式估计峰值?
很抱歉这个非常基本的问题,并提前非常感谢您。我的代码如下。
import numpy as np
import matplotlib.pyplot as plt
import IGM
import scipy.integrate as integrate
SF = np.load('StarForming.npy')
lam = SF[0]
SED = SF[1]
filters = ['f435w','f606w','f814w','f105w','f125w','f140w','f160w']
filters_wl = {'f435w':0.435,'f606w':0.606,'f814w':0.814,'f105w':1.05,'f125w':1.25,'f140w':1.40,'f160w':1.60} # filter dictionary to give wavelengths of filters in microns
fT = {} # this is a dictionary
for f in filters:
data = np.loadtxt(f+'.txt').T
fT[f]= data
fluxes = {}
for f in filters: fluxes[f] = [] # make empty list for each
redshifts = np.arange(0.0,10.0,0.1) # redshifts going from 0 to 10
for z in redshifts:
lamz = lam * (1. + z)
obsSED = SED * IGM.madau(lamz, z)
for f in filters:
newT = np.interp(lamz,fT[f][0],fT[f][1]) # for each filter, refer back
bb_flux = integrate.trapz((1./lamz)*obsSED*newT,x=lamz)/integrate.trapz((1./lamz)*newT,x=lamz)
# 1st bit integrates, 2nd bit divides by area under filter to normalise filter
# loops over all z, for all z it creates a new SED, redshift wl grid
fluxes[f].append(bb_flux)
for f in filters: fluxes[f] = np.array(fluxes[f])
colour = -2.5*np.log10(fluxes['f435w']/fluxes['f606w'])
plt.plot(redshifts,colour)
plt.xlabel('Redshift')
plt.ylabel('Colour')
plt.show