Съдържание

Условие 14.1.14.2.Решение

IAO 2022, Практически тур — Задача 14. Hubble parameter

Оригинал на условието (PDF)Съобщи за грешка

Всички материали от IAO 2022

II International Remote Astronomy Olympiad — Practical round · 15 октомври 2022 г.

Practical round. Problems to solve

II International Remote Astronomy Olympiad. Matera, Italy, 15–24 October 2022.

Note: problems for Group α — 13, 14, for Group β — 14, 15, for Group γ — 13, 14, 15.

Source notes and availability

The file contains three independent tasks and all tabulated data, theoretical curves and a blank plotting grid. Its fourth page repeats tasks14 and15; this does not create new tasks. The sunspot dates are printed as October2018 and retained. The star table uses labels A–I,L,M as printed. The isochrone diagram numbers its curves but provides no numerical age key, although task15 asks for an age. No matching official solutions or additional reference files were found in the complete same-year archive catalogue.

Условие

Estimate the Hubble parameter with type Ia Supernovae (SN Ia).

The most accurate measurements of the Hubble parameter $H_0$ are based on observations of type Ia Supernovae in addition to information of the distances to nearby galaxies using Cepheid stars. Although this study initially started from the optical bands, it was found that the use of near infrared (in the J band) involves considering far fewer corrections. Nine neighbouring galaxies are used as near infrared calibrators whose distances, as distance modulus, are known through the cepheids and in addition in that galaxies SN Ia have been observed:

The data is presented in the Table 14.1 (neighbouring galaxies, columns: supernova Ia, host galaxy, $m_J$ (J magnitude), distance modulus by cepheids) and Table 14.2 (more distant galaxies, columns: supernova Ia, $m_J$ (J magnitude), host galaxy, redshift $z$ ).

14.1 Using Table 14.1, draw the graph "distance module vs magnitude J".

14.2 Apparent magnitude, absolute magnitude, Hubble parameter $H_0$ , and redshift $z$ , are connected by a formula of the following form:

m_J-M_J=A\cdot\log(H_0)+B\cdot\log(z)+C;

Calculate the values of coefficients A, B and C.

14.3 Using the data in Table 14.2 (galaxies with a large distance), draw the necessary graph and, using this graph ...

14.4 ... get the average value obtained for $H_0$ , calculating it for 4 supernovae using the formula obtained above.

14.1.

SN Ia	HG	$m_J$	DM
SN2001el	NGC1448	12.837	31.311
SN2002fk	NGC1309	13.749	32.523
SN2003du	UGC9391	14.325	32.919
SN2005cf	NGC5917	13.791	32.263
SN2007af	NGC5584	13.446	31.786
SN2011by	NGC3972	13.218	31.587
SN2011fe	M101	10.464	29.135
SN2012cg	NGC4424	12.285	31.08
SN2015F	NGC2442	13.081	31.511

14.2.

SN Ia	$m_J$	HG	$z$
SN2004eo	15.5	NGC6928	0.015
SN2007bd	17.1	UGC4455	0.032
SN2009ad	16.9	UGC3236	0.029
SN2001ao	14.9	IC2973	0.012

Решение

Внимание: Непълно решение

В архива няма официално решение на тази задача.

Теми и трудност

Трудност: неоценена.

Галактики и космология · Светлина и астрономически измервания · Разширение на Вселената · Определяне на разстояния

Предпоставки: Разширена олимпиадна подготовка

Оригинал в Архива: prac-IRAO2022.pdf