Multimessenger Transients in the X-Ray Light
A special issue of Galaxies (ISSN 2075-4434).
Deadline for manuscript submissions: 10 June 2026 | Viewed by 19
Special Issue Editor
Interests: stellar astrophysics; compact objects; multi-wavelength observations
Special Issues, Collections and Topics in MDPI journals
Special Issue Information
Dear Colleagues,
Galactic X-ray sources (mostly X-ray binaries) with a compact object (neutron star or black hole) and a donor star are characterised by marked X-ray variability, which reflects variability in the accretion process. In addition, a more erratic variability is observed, such as X-ray bursts or flares caused by thermonuclear burning events on the neutron star's surface. Recently, a few X-ray binaries have been found to change from an accretion-powered state to a rotation-powered state, where accretion stops, and the neutron star becomes an active radio pulsar, albeit with a lower X-ray luminosity. This can be powered by the pulsar itself or by intra-binary shocks between the pulsar wind and that of the companion. Not to forget, the mysterious Tidal Disruption Events, where the donor star is completely disrupted by the gravitational pull of the compact object, producing strong X-ray flashes. On the other side of the time scale, microvariability is observed, apart from x-ray pulsations and quasi-periodic variability in the accretion disk. In many cases, all the aforementioned variability is accompanied by variability at other wavelengths, notably in the optical and infrared. The recent discovery of gamma-ray emission from X-ray binaries has allowed us to connect variability in the low and very high energy regimes. These are only a few examples of multiwavelength variability in Galactic X-ray sources. Whether gravitational wave (GW) emission can be observed in these systems is debatable. With two objects spiralling in, this must exist, but it is probably quenched by the accretion flow. Therefore, these sources alternate between low- and high-emission states, resulting in a clear transient behaviour.
In this Special Issue, we aim to set the state of the art in multiwavelength studies of Galactic X-ray sources and make the case for possible GW emission from such sources.
Prof. Dr. Roberto Mignani
Guest Editor
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Galaxies is an international peer-reviewed open access semimonthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.
Keywords
- X-ray
- galactic sources
- emission characteristics
- variability
- multi-wavelength counterparts
- gravitational wave detection
Benefits of Publishing in a Special Issue
- Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
- Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
- Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
- External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
- Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.
Further information on MDPI's Special Issue policies can be found here.
