Astronomy 275 Lecture Notes, Spring 2009 - download pdf or read online

By Edward L. Wright, Phd, UCLA

Show description

Read or Download Astronomy 275 Lecture Notes, Spring 2009 PDF

Similar astronomy books

Read e-book online All About Space, Issue 43 PDF

Each factor All approximately house offers interesting articles and contours on all points of house and area trip with extraordinary images and full-colour illustrations that convey the superb universe round us to lifestyles.

Read e-book online Galileo (A Brief Insight) PDF

In a startling reinterpretation of the proof, Stillman Drake advances the speculation that Galileo’s condemnation by means of the Inquisition was once prompted now not by means of his defiance of the Church, yet by means of the hostility of latest philosophers. Galileo’s personal fantastically lucid arguments are used to teach how his clinical method—based on a seek no longer for explanations yet for laws—was completely divorced from the Aristotelian method of physics.

Origins: How the Planets, Stars, Galaxies, and the Universe - download pdf or read online

This publication appears to be like at solutions to the most important questions in astronomy – the questions of ways the planets, stars, galaxies and the universe have been shaped. over the past decade, a revolution in observational astronomy has produced attainable solutions to 3 of those questions. This publication describes this revolution.

Additional info for Astronomy 275 Lecture Notes, Spring 2009

Example text

This is normally defined for the case where hν << kTe << me c2 . Since the x variable is defined 60 µ Residual [kJy/sr] 100 y 0 -100 0 5 10 ν [/cm] 15 20 Fig. 5 × 10−5 and µ = 9 × 10−5 . as hν/kTe , these assumptions make dx very small, and thus the only term that contributes significantly to ∂n/∂y is the ∂n/∂x term: the n and n2 terms are unimportant in this limit. For a blackbody n = 1/(ex − 1) we get ∂n ∂ ∂n = x−2 x4 ∂y ∂x ∂x ∂ x4 ex = −x−2 ∂x (ex − 1)2 2x4 e2x − (ex − 1)(4x3 ex + x4 ex ) = x−2 (ex − 1)3 x2 e2x − 4xe2x + 4xex + x2 ex = (ex − 1)3 2 x x x x (e + 1) − 4x(e − 1) = e (ex − 1)3 61 = xex (ex − 1)2 x ex + 1 −4 ex − 1 (193) Thus the change in intensity due to y is (to first order) 2hν 3 ∂Iν xex = 2 ∂y c (ex − 1)2 x ex + 1 −4 ex − 1 with x = hν/kT◦ (194) The derivative of the Planck function with respect to T is given by T so ∂Iν ∂y 2hν 3 xex ∂Bν (T ) = 2 ∂T c (ex − 1)2 (195) can be described as a changed Planck brightness temperature: Tν = T◦ 1 + y x ex + 1 − 4 + ...

And a(to + ∆to ) = a(to )(1 + H(to )∆to + . ). But we also know that ∆te = ∆to /(1 + z). Combining gives a(to + ∆to ) a(te + ∆te ) a(to )(1 + H(to )∆to + . . = a(te )(1 + H(te )∆to /(1 + z) + . . a(to ) (1 + [H◦ − H(z)/(1 + z)]∆to + . ) = a(te ) = (1 + z)(to ) + [(1 + z)H◦ − H(z)]∆to (1 + z)(to + ∆to ) = (80) Thus the rate of change of the redshift of a comoving object is d(1 + z) = (1 + z)H◦ − H(te ) dto = H◦ (1 + z) 1 − (81) [1 − Ωtot,◦ ] + Ωv◦ /(1 + z)2 + Ωm◦ (1 + z) + Ωr◦ (1 + z)2 For example, consider a source with z = 3 in a Universe with Ωm◦ = 1.

1 Redshift z 1 Fig. — Distance modulus vs. redshift for high redshift Type Ia supernovae. Data are taken from the Union catalog published by Kowalski et al. (2008, ApJ, 686, 749). The distance modulus is DM = 5 log(DL (z)/D◦ ), normalized to D◦ = 10 pc for this plot. 27; green for Ωv◦ = 0, Ωm◦ = 0; black for Ωv◦ = 0, Ωm◦ = 1; and red for Ωv◦ = 0, Ωm◦ = 2. The large number of objects, and the large errorbars for individual objects, make it difficult to see the goodness of fits for these models. 2 Ned Wright - 13 May 2008 Fig.

Download PDF sample

Astronomy 275 Lecture Notes, Spring 2009 by Edward L. Wright, Phd, UCLA


by George
4.2

Rated 4.37 of 5 – based on 9 votes