# Radiation astronomy/First astronomical X-ray source/Quiz

X-ray emission from Hyakutake is seen by the ROSAT satellite. Credit: NASA.

First astronomical X-ray source is a lecture for the advanced course on X-ray astronomy. You are free to take this quiz based on the lecture at any time. Once you’ve read and studied the lecture itself, the links contained within the lecture, listed under See also, External links and in the {{principles of radiation astronomy}} template, you should have adequate background to achieve 100 %.

Suggestion: Have the lecture available in a separate window.

Enjoy learning by doing!

## Quiz

1 Object identification:

 What "mystery object" made a sudden appearance on February 21, 2006, and was observed to have an X-ray glow around it by the X-ray observatory satellite XMM Newton in early August 2006?

2 Yes or No, An X-ray may have a wavelength as long as 10 nm.

 Yes No

3 The first astronomical X-ray source in the constellation Dorado is likely to be which of the following?

 the Sun the Small Magellanic Cloud Scorpius X-1 the Large Magellanic Cloud the Crab Nebula

4 Which of the following may be a type of X-ray binary?

 a dwarf planet a member of the Oort belt a soft X-ray transient the polar regions (North and South) of Jupiter an X-ray burster Hercules X-1 an X-ray emitting Be star

5 Complete the text:

 publication in print contains the identification of all of the first X-ray sources discovered for each of the 88 (or 89) constellations.

6 True or False, The Sun is an X-ray source in the constellation Lupus.

 TRUE FALSE

7 A natural X-ray source has been detected by an X-ray counter at a site on the ground (Earth) from what astronomical X-ray source?

 the Sun the ionosphere the diffuse X-ray background Serpens X-1 the Moon lightning

8 Which of the following is associated with the diffuse X-ray background?

 the Sun rather consistently observed over a wide range of energies an Aitoff-Hammer equal-area map in galactic coordinates an isotropic X-ray background flux was obtained in 1956 an early high-energy end was obtained by instruments on board Ranger 3 super soft X-rays are absorbed by galactic neutral hydrogen

9 True or False, A professional astronomer holding an X-ray detector in their hands while working on the International Space Station is a primary astronomical X-ray source.

 TRUE FALSE

10 The Sun is a natural X-ray source because X-rays originate from what astronomical X-ray source?

 a coronal cloud about the Sun the diffuse X-ray background sunspots the photosphere nucleosynthesis in the center of the Sun lightning

11 Which of the following is associated with the Sun as a possible first X-ray source?

 lofting an X-ray detector with a V-2 rocket from White Sands Proving Grounds on August 5, 1948 in the late 1930s, "the presence of a very hot, tenuous gas surrounding the Sun ... was inferred indirectly from optical coronal lines of highly ionized species" early theoretical estimates of black body radiation from the solar corona “extensive 1/4 keV emission in the Galactic halo” its overall redness has decreased ionizing radiation that may originate deep within the Sun does not reach the bottom of a sunspot

12 True or False, The bottom of a sunspot ~400 km deep is cooler than the bottom of the photosphere.

 TRUE FALSE

13 Which of the following is not an astronomical X-ray source?

 the planet Mercury traces of the element gold in the Sun’s photosphere the solar wind Cepheus X-1 nucleosynthesis near the surface of the Sun lightning on Jupiter

14 A first X-ray source located roughly 9000 light years away in the constellation Scorpius is

15 True or False, Alpha Apodis is a known (SIMBAD) X-ray source.

 TRUE FALSE

16 Complete the text:

 A well-known black hole (or black hole candidate) and galactic X-ray source in the constellation Cygnus is .

17 Which of the following is not an astronomical X-ray source?

 Io Comet Lulin the Moon Carina X-1 Centaurus X-2 EZ Aquarii

18 True or False, Cassiopeia X-1 was first detected during a June 16, 1964, Aerobee sounding rocket flight.

 TRUE FALSE

19 Of the discovery of the first extrasolar X-ray source, the instrumentation had been designed for an attempt to observe X-rays from the

20 Complete the text:

 A non-SI unit of spectral X-ray flux density is called the .

21 True or False, A high-mass X-ray binary designation indicates that the X-ray source is a high-mass neutron star.

 TRUE FALSE

22 Complete the text:

 An X-ray binary star exhibiting periodic and rapid increases in luminosity (typically a factor of 10 or greater) peaked in the X-ray regime is called an .

23 True or False, The flux density or monochromatic flux, ${\displaystyle S}$, of a source is the integral of the spectral radiance, ${\displaystyle B}$, over the source solid angle:

${\displaystyle S=\iint _{\mathrm {source} }B(\Omega )\mathrm {d} \Omega =\iint _{\mathrm {source} }B(\theta ,\phi )\sin \theta \,d\theta \,d\varphi }$.

 TRUE FALSE

## Hypotheses

1. The first astronomical X-ray source may have been the Earth.