Editing X-ray astronomy (section)

==Astrophysical sources of X-rays==
{{main|Astrophysical X-ray source}}
[[File:PIA20061 - Andromeda in High-Energy X-rays, Figure 1.jpg|thumb|center|500px|[[Andromeda Galaxy]] – in high-energy X-ray and [[Ultraviolet astronomy|ultraviolet]] light (released 5 January 2016).]]
[[File:Herx1 lc.gif|200px|thumb|This light curve of Her X-1 shows long term and medium term variability. Each pair of vertical lines delineate the eclipse of the compact object behind its companion star. In this case, the companion is a two solar-mass star with a radius of nearly four times that of the Sun. This eclipse shows us the orbital period of the system, 1.7 days.]]
Several types of astrophysical objects emit, fluoresce, or reflect X-rays, from [[galaxy cluster]]s, through black holes in [[active galactic nucleus|active galactic nuclei]] (AGN) to galactic objects such as [[supernova remnant]]s, stars, and [[binary star]]s containing a [[white dwarf]] ([[cataclysmic variable star]]s and [[super soft X-ray source]]s), neutron star or black hole ([[X-ray binaries]]). Some [[Solar System]] bodies emit X-rays, the most notable being the [[Moon]], although most of the X-ray brightness of the Moon arises from reflected solar X-rays. A combination of many unresolved X-ray sources is thought to produce the observed [[X-ray background]]. The X-ray continuum can arise from [[bremsstrahlung]], [[Thermal radiation|black-body radiation]], [[synchrotron radiation]], or what is called [[Compton scattering#Inverse Compton scattering|inverse Compton scattering]] of lower-energy photons by relativistic electrons, knock-on collisions of fast protons with atomic electrons, and atomic recombination, with or without additional electron transitions.<ref name=Morrison>{{Cite journal|author=Morrison P |title=Extrasolar X-ray Sources |journal=Annual Review of Astronomy and Astrophysics|date=1967 |volume=5 |issue=1 |page=325 |doi=10.1146/annurev.aa.05.090167.001545 |bibcode=1967ARA&A...5..325M}}</ref>

An [[intermediate-mass X-ray binary]] (IMXB) is a binary star system where one of the components is a neutron star or a black hole. The other component is an intermediate mass star.<ref name=Podsiadlowski>{{cite journal |author=Podsiadlowski P |author2=Rappaport S |author3=Pfahl E |title=Evolutionary Binary Sequences for Low- and Intermediate-Mass X-ray Binaries |date=2001 |doi=10.1086/324686 |journal=The Astrophysical Journal |volume=565 |issue=2 |pages=1107 |arxiv=astro-ph/0107261|bibcode = 2002ApJ...565.1107P |s2cid=16381236 }}</ref>

[[Hercules X-1]] is composed of a neutron star accreting matter from a normal star (HZ Herculis) probably due to Roche lobe overflow. X-1 is the prototype for the massive X-ray binaries although it falls on the borderline, {{Solar mass|~2|link=y}}, between high- and low-mass X-ray binaries.<ref name=Priedhorsky>{{Cite journal|author=Priedhorsky WC|author2= Holt SS |title=Long-term cycles in cosmic X-ray sources |journal=Space Science Reviews|volume=45|date=1987|issue=3–4 |page=291|doi=10.1007/BF00171997 |bibcode=1987SSRv...45..291P|s2cid= 120443194 }}</ref>

In July 2020, astronomers reported the observation of a "[[Tidal disruption event|hard tidal disruption event candidate]]" associated with ASASSN-20hx, located near the nucleus of galaxy NGC 6297, and noted that the observation represented one of the "very few tidal disruption events with [[X-ray#Soft and hard X-rays|hard powerlaw X-ray spectra]]".<ref name="AT-20200725">{{cite news |last=Lin |first=Dacheng |title=ATel #13895: ASASSN-20hx is a Hard Tidal Disruption Event Candidate |url=http://www.astronomerstelegram.org/?read=13895 |date=25 July 2020 |work=[[The Astronomer's Telegram]] |access-date=25 July 2020 }}</ref><ref name="AT-20200724">{{cite news |author=Hinkle, J.T. |display-authors=et al. |title=Atel #13893: Classification of ASASSN-20hx as a Tidal Disruption Event Candidate |url=http://www.astronomerstelegram.org/?read=13893 |date=24 July 2020 |work=[[The Astronomer's Telegram]] |access-date=24 July 2020 }}</ref>